1 /*
2  * Copyright © 2014 Red Hat
3  *
4  * Permission to use, copy, modify, distribute, and sell this software and its
5  * documentation for any purpose is hereby granted without fee, provided that
6  * the above copyright notice appear in all copies and that both that copyright
7  * notice and this permission notice appear in supporting documentation, and
8  * that the name of the copyright holders not be used in advertising or
9  * publicity pertaining to distribution of the software without specific,
10  * written prior permission.  The copyright holders make no representations
11  * about the suitability of this software for any purpose.  It is provided "as
12  * is" without express or implied warranty.
13  *
14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
20  * OF THIS SOFTWARE.
21  */
22 
23 #include <linux/bitfield.h>
24 #include <linux/delay.h>
25 #include <linux/errno.h>
26 #include <linux/i2c.h>
27 #include <linux/init.h>
28 #include <linux/kernel.h>
29 #include <linux/random.h>
30 #include <linux/sched.h>
31 #include <linux/seq_file.h>
32 #include <linux/iopoll.h>
33 
34 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
35 #include <linux/stacktrace.h>
36 #include <linux/sort.h>
37 #include <linux/timekeeping.h>
38 #include <linux/math64.h>
39 #endif
40 
41 #include <drm/drm_atomic.h>
42 #include <drm/drm_atomic_helper.h>
43 #include <drm/drm_dp_mst_helper.h>
44 #include <drm/drm_drv.h>
45 #include <drm/drm_print.h>
46 #include <drm/drm_probe_helper.h>
47 
48 #include "drm_crtc_helper_internal.h"
49 #include "drm_dp_mst_topology_internal.h"
50 
51 /**
52  * DOC: dp mst helper
53  *
54  * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
55  * protocol. The helpers contain a topology manager and bandwidth manager.
56  * The helpers encapsulate the sending and received of sideband msgs.
57  */
58 struct drm_dp_pending_up_req {
59 	struct drm_dp_sideband_msg_hdr hdr;
60 	struct drm_dp_sideband_msg_req_body msg;
61 	struct list_head next;
62 };
63 
64 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
65 				  char *buf);
66 
67 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
68 
69 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
70 				     int id,
71 				     struct drm_dp_payload *payload);
72 
73 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
74 				 struct drm_dp_mst_port *port,
75 				 int offset, int size, u8 *bytes);
76 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
77 				  struct drm_dp_mst_port *port,
78 				  int offset, int size, u8 *bytes);
79 
80 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
81 				    struct drm_dp_mst_branch *mstb);
82 
83 static void
84 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
85 				   struct drm_dp_mst_branch *mstb);
86 
87 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
88 					   struct drm_dp_mst_branch *mstb,
89 					   struct drm_dp_mst_port *port);
90 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
91 				 u8 *guid);
92 
93 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
94 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
95 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
96 
97 #define DBG_PREFIX "[dp_mst]"
98 
99 #define DP_STR(x) [DP_ ## x] = #x
100 
drm_dp_mst_req_type_str(u8 req_type)101 static const char *drm_dp_mst_req_type_str(u8 req_type)
102 {
103 	static const char * const req_type_str[] = {
104 		DP_STR(GET_MSG_TRANSACTION_VERSION),
105 		DP_STR(LINK_ADDRESS),
106 		DP_STR(CONNECTION_STATUS_NOTIFY),
107 		DP_STR(ENUM_PATH_RESOURCES),
108 		DP_STR(ALLOCATE_PAYLOAD),
109 		DP_STR(QUERY_PAYLOAD),
110 		DP_STR(RESOURCE_STATUS_NOTIFY),
111 		DP_STR(CLEAR_PAYLOAD_ID_TABLE),
112 		DP_STR(REMOTE_DPCD_READ),
113 		DP_STR(REMOTE_DPCD_WRITE),
114 		DP_STR(REMOTE_I2C_READ),
115 		DP_STR(REMOTE_I2C_WRITE),
116 		DP_STR(POWER_UP_PHY),
117 		DP_STR(POWER_DOWN_PHY),
118 		DP_STR(SINK_EVENT_NOTIFY),
119 		DP_STR(QUERY_STREAM_ENC_STATUS),
120 	};
121 
122 	if (req_type >= ARRAY_SIZE(req_type_str) ||
123 	    !req_type_str[req_type])
124 		return "unknown";
125 
126 	return req_type_str[req_type];
127 }
128 
129 #undef DP_STR
130 #define DP_STR(x) [DP_NAK_ ## x] = #x
131 
drm_dp_mst_nak_reason_str(u8 nak_reason)132 static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
133 {
134 	static const char * const nak_reason_str[] = {
135 		DP_STR(WRITE_FAILURE),
136 		DP_STR(INVALID_READ),
137 		DP_STR(CRC_FAILURE),
138 		DP_STR(BAD_PARAM),
139 		DP_STR(DEFER),
140 		DP_STR(LINK_FAILURE),
141 		DP_STR(NO_RESOURCES),
142 		DP_STR(DPCD_FAIL),
143 		DP_STR(I2C_NAK),
144 		DP_STR(ALLOCATE_FAIL),
145 	};
146 
147 	if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
148 	    !nak_reason_str[nak_reason])
149 		return "unknown";
150 
151 	return nak_reason_str[nak_reason];
152 }
153 
154 #undef DP_STR
155 #define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
156 
drm_dp_mst_sideband_tx_state_str(int state)157 static const char *drm_dp_mst_sideband_tx_state_str(int state)
158 {
159 	static const char * const sideband_reason_str[] = {
160 		DP_STR(QUEUED),
161 		DP_STR(START_SEND),
162 		DP_STR(SENT),
163 		DP_STR(RX),
164 		DP_STR(TIMEOUT),
165 	};
166 
167 	if (state >= ARRAY_SIZE(sideband_reason_str) ||
168 	    !sideband_reason_str[state])
169 		return "unknown";
170 
171 	return sideband_reason_str[state];
172 }
173 
174 static int
drm_dp_mst_rad_to_str(const u8 rad[8],u8 lct,char * out,size_t len)175 drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
176 {
177 	int i;
178 	u8 unpacked_rad[16];
179 
180 	for (i = 0; i < lct; i++) {
181 		if (i % 2)
182 			unpacked_rad[i] = rad[i / 2] >> 4;
183 		else
184 			unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
185 	}
186 
187 	/* TODO: Eventually add something to printk so we can format the rad
188 	 * like this: 1.2.3
189 	 */
190 	return snprintf(out, len, "%*phC", lct, unpacked_rad);
191 }
192 
193 /* sideband msg handling */
drm_dp_msg_header_crc4(const uint8_t * data,size_t num_nibbles)194 static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
195 {
196 	u8 bitmask = 0x80;
197 	u8 bitshift = 7;
198 	u8 array_index = 0;
199 	int number_of_bits = num_nibbles * 4;
200 	u8 remainder = 0;
201 
202 	while (number_of_bits != 0) {
203 		number_of_bits--;
204 		remainder <<= 1;
205 		remainder |= (data[array_index] & bitmask) >> bitshift;
206 		bitmask >>= 1;
207 		bitshift--;
208 		if (bitmask == 0) {
209 			bitmask = 0x80;
210 			bitshift = 7;
211 			array_index++;
212 		}
213 		if ((remainder & 0x10) == 0x10)
214 			remainder ^= 0x13;
215 	}
216 
217 	number_of_bits = 4;
218 	while (number_of_bits != 0) {
219 		number_of_bits--;
220 		remainder <<= 1;
221 		if ((remainder & 0x10) != 0)
222 			remainder ^= 0x13;
223 	}
224 
225 	return remainder;
226 }
227 
drm_dp_msg_data_crc4(const uint8_t * data,u8 number_of_bytes)228 static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
229 {
230 	u8 bitmask = 0x80;
231 	u8 bitshift = 7;
232 	u8 array_index = 0;
233 	int number_of_bits = number_of_bytes * 8;
234 	u16 remainder = 0;
235 
236 	while (number_of_bits != 0) {
237 		number_of_bits--;
238 		remainder <<= 1;
239 		remainder |= (data[array_index] & bitmask) >> bitshift;
240 		bitmask >>= 1;
241 		bitshift--;
242 		if (bitmask == 0) {
243 			bitmask = 0x80;
244 			bitshift = 7;
245 			array_index++;
246 		}
247 		if ((remainder & 0x100) == 0x100)
248 			remainder ^= 0xd5;
249 	}
250 
251 	number_of_bits = 8;
252 	while (number_of_bits != 0) {
253 		number_of_bits--;
254 		remainder <<= 1;
255 		if ((remainder & 0x100) != 0)
256 			remainder ^= 0xd5;
257 	}
258 
259 	return remainder & 0xff;
260 }
drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr * hdr)261 static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
262 {
263 	u8 size = 3;
264 
265 	size += (hdr->lct / 2);
266 	return size;
267 }
268 
drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr * hdr,u8 * buf,int * len)269 static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
270 					   u8 *buf, int *len)
271 {
272 	int idx = 0;
273 	int i;
274 	u8 crc4;
275 
276 	buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
277 	for (i = 0; i < (hdr->lct / 2); i++)
278 		buf[idx++] = hdr->rad[i];
279 	buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
280 		(hdr->msg_len & 0x3f);
281 	buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
282 
283 	crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
284 	buf[idx - 1] |= (crc4 & 0xf);
285 
286 	*len = idx;
287 }
288 
drm_dp_decode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr * hdr,u8 * buf,int buflen,u8 * hdrlen)289 static bool drm_dp_decode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
290 					   u8 *buf, int buflen, u8 *hdrlen)
291 {
292 	u8 crc4;
293 	u8 len;
294 	int i;
295 	u8 idx;
296 
297 	if (buf[0] == 0)
298 		return false;
299 	len = 3;
300 	len += ((buf[0] & 0xf0) >> 4) / 2;
301 	if (len > buflen)
302 		return false;
303 	crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
304 
305 	if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
306 		DRM_DEBUG_KMS("crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
307 		return false;
308 	}
309 
310 	hdr->lct = (buf[0] & 0xf0) >> 4;
311 	hdr->lcr = (buf[0] & 0xf);
312 	idx = 1;
313 	for (i = 0; i < (hdr->lct / 2); i++)
314 		hdr->rad[i] = buf[idx++];
315 	hdr->broadcast = (buf[idx] >> 7) & 0x1;
316 	hdr->path_msg = (buf[idx] >> 6) & 0x1;
317 	hdr->msg_len = buf[idx] & 0x3f;
318 	idx++;
319 	hdr->somt = (buf[idx] >> 7) & 0x1;
320 	hdr->eomt = (buf[idx] >> 6) & 0x1;
321 	hdr->seqno = (buf[idx] >> 4) & 0x1;
322 	idx++;
323 	*hdrlen = idx;
324 	return true;
325 }
326 
327 void
drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body * req,struct drm_dp_sideband_msg_tx * raw)328 drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
329 			   struct drm_dp_sideband_msg_tx *raw)
330 {
331 	int idx = 0;
332 	int i;
333 	u8 *buf = raw->msg;
334 
335 	buf[idx++] = req->req_type & 0x7f;
336 
337 	switch (req->req_type) {
338 	case DP_ENUM_PATH_RESOURCES:
339 	case DP_POWER_DOWN_PHY:
340 	case DP_POWER_UP_PHY:
341 		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
342 		idx++;
343 		break;
344 	case DP_ALLOCATE_PAYLOAD:
345 		buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
346 			(req->u.allocate_payload.number_sdp_streams & 0xf);
347 		idx++;
348 		buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
349 		idx++;
350 		buf[idx] = (req->u.allocate_payload.pbn >> 8);
351 		idx++;
352 		buf[idx] = (req->u.allocate_payload.pbn & 0xff);
353 		idx++;
354 		for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
355 			buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
356 				(req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
357 			idx++;
358 		}
359 		if (req->u.allocate_payload.number_sdp_streams & 1) {
360 			i = req->u.allocate_payload.number_sdp_streams - 1;
361 			buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
362 			idx++;
363 		}
364 		break;
365 	case DP_QUERY_PAYLOAD:
366 		buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
367 		idx++;
368 		buf[idx] = (req->u.query_payload.vcpi & 0x7f);
369 		idx++;
370 		break;
371 	case DP_REMOTE_DPCD_READ:
372 		buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
373 		buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
374 		idx++;
375 		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
376 		idx++;
377 		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
378 		idx++;
379 		buf[idx] = (req->u.dpcd_read.num_bytes);
380 		idx++;
381 		break;
382 
383 	case DP_REMOTE_DPCD_WRITE:
384 		buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
385 		buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
386 		idx++;
387 		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
388 		idx++;
389 		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
390 		idx++;
391 		buf[idx] = (req->u.dpcd_write.num_bytes);
392 		idx++;
393 		memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
394 		idx += req->u.dpcd_write.num_bytes;
395 		break;
396 	case DP_REMOTE_I2C_READ:
397 		buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
398 		buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
399 		idx++;
400 		for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
401 			buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
402 			idx++;
403 			buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
404 			idx++;
405 			memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
406 			idx += req->u.i2c_read.transactions[i].num_bytes;
407 
408 			buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
409 			buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
410 			idx++;
411 		}
412 		buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
413 		idx++;
414 		buf[idx] = (req->u.i2c_read.num_bytes_read);
415 		idx++;
416 		break;
417 
418 	case DP_REMOTE_I2C_WRITE:
419 		buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
420 		idx++;
421 		buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
422 		idx++;
423 		buf[idx] = (req->u.i2c_write.num_bytes);
424 		idx++;
425 		memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
426 		idx += req->u.i2c_write.num_bytes;
427 		break;
428 	case DP_QUERY_STREAM_ENC_STATUS: {
429 		const struct drm_dp_query_stream_enc_status *msg;
430 
431 		msg = &req->u.enc_status;
432 		buf[idx] = msg->stream_id;
433 		idx++;
434 		memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
435 		idx += sizeof(msg->client_id);
436 		buf[idx] = 0;
437 		buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
438 		buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
439 		buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
440 		buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
441 		idx++;
442 		}
443 		break;
444 	}
445 	raw->cur_len = idx;
446 }
447 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
448 
449 /* Decode a sideband request we've encoded, mainly used for debugging */
450 int
drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx * raw,struct drm_dp_sideband_msg_req_body * req)451 drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
452 			   struct drm_dp_sideband_msg_req_body *req)
453 {
454 	const u8 *buf = raw->msg;
455 	int i, idx = 0;
456 
457 	req->req_type = buf[idx++] & 0x7f;
458 	switch (req->req_type) {
459 	case DP_ENUM_PATH_RESOURCES:
460 	case DP_POWER_DOWN_PHY:
461 	case DP_POWER_UP_PHY:
462 		req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
463 		break;
464 	case DP_ALLOCATE_PAYLOAD:
465 		{
466 			struct drm_dp_allocate_payload *a =
467 				&req->u.allocate_payload;
468 
469 			a->number_sdp_streams = buf[idx] & 0xf;
470 			a->port_number = (buf[idx] >> 4) & 0xf;
471 
472 			WARN_ON(buf[++idx] & 0x80);
473 			a->vcpi = buf[idx] & 0x7f;
474 
475 			a->pbn = buf[++idx] << 8;
476 			a->pbn |= buf[++idx];
477 
478 			idx++;
479 			for (i = 0; i < a->number_sdp_streams; i++) {
480 				a->sdp_stream_sink[i] =
481 					(buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
482 			}
483 		}
484 		break;
485 	case DP_QUERY_PAYLOAD:
486 		req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
487 		WARN_ON(buf[++idx] & 0x80);
488 		req->u.query_payload.vcpi = buf[idx] & 0x7f;
489 		break;
490 	case DP_REMOTE_DPCD_READ:
491 		{
492 			struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
493 
494 			r->port_number = (buf[idx] >> 4) & 0xf;
495 
496 			r->dpcd_address = (buf[idx] << 16) & 0xf0000;
497 			r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
498 			r->dpcd_address |= buf[++idx] & 0xff;
499 
500 			r->num_bytes = buf[++idx];
501 		}
502 		break;
503 	case DP_REMOTE_DPCD_WRITE:
504 		{
505 			struct drm_dp_remote_dpcd_write *w =
506 				&req->u.dpcd_write;
507 
508 			w->port_number = (buf[idx] >> 4) & 0xf;
509 
510 			w->dpcd_address = (buf[idx] << 16) & 0xf0000;
511 			w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
512 			w->dpcd_address |= buf[++idx] & 0xff;
513 
514 			w->num_bytes = buf[++idx];
515 
516 			w->bytes = kmemdup(&buf[++idx], w->num_bytes,
517 					   GFP_KERNEL);
518 			if (!w->bytes)
519 				return -ENOMEM;
520 		}
521 		break;
522 	case DP_REMOTE_I2C_READ:
523 		{
524 			struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
525 			struct drm_dp_remote_i2c_read_tx *tx;
526 			bool failed = false;
527 
528 			r->num_transactions = buf[idx] & 0x3;
529 			r->port_number = (buf[idx] >> 4) & 0xf;
530 			for (i = 0; i < r->num_transactions; i++) {
531 				tx = &r->transactions[i];
532 
533 				tx->i2c_dev_id = buf[++idx] & 0x7f;
534 				tx->num_bytes = buf[++idx];
535 				tx->bytes = kmemdup(&buf[++idx],
536 						    tx->num_bytes,
537 						    GFP_KERNEL);
538 				if (!tx->bytes) {
539 					failed = true;
540 					break;
541 				}
542 				idx += tx->num_bytes;
543 				tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
544 				tx->i2c_transaction_delay = buf[idx] & 0xf;
545 			}
546 
547 			if (failed) {
548 				for (i = 0; i < r->num_transactions; i++) {
549 					tx = &r->transactions[i];
550 					kfree(tx->bytes);
551 				}
552 				return -ENOMEM;
553 			}
554 
555 			r->read_i2c_device_id = buf[++idx] & 0x7f;
556 			r->num_bytes_read = buf[++idx];
557 		}
558 		break;
559 	case DP_REMOTE_I2C_WRITE:
560 		{
561 			struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
562 
563 			w->port_number = (buf[idx] >> 4) & 0xf;
564 			w->write_i2c_device_id = buf[++idx] & 0x7f;
565 			w->num_bytes = buf[++idx];
566 			w->bytes = kmemdup(&buf[++idx], w->num_bytes,
567 					   GFP_KERNEL);
568 			if (!w->bytes)
569 				return -ENOMEM;
570 		}
571 		break;
572 	case DP_QUERY_STREAM_ENC_STATUS:
573 		req->u.enc_status.stream_id = buf[idx++];
574 		for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
575 			req->u.enc_status.client_id[i] = buf[idx++];
576 
577 		req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
578 							   buf[idx]);
579 		req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
580 								 buf[idx]);
581 		req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
582 							      buf[idx]);
583 		req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
584 								    buf[idx]);
585 		break;
586 	}
587 
588 	return 0;
589 }
590 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
591 
592 void
drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body * req,int indent,struct drm_printer * printer)593 drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
594 				  int indent, struct drm_printer *printer)
595 {
596 	int i;
597 
598 #define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
599 	if (req->req_type == DP_LINK_ADDRESS) {
600 		/* No contents to print */
601 		P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
602 		return;
603 	}
604 
605 	P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
606 	indent++;
607 
608 	switch (req->req_type) {
609 	case DP_ENUM_PATH_RESOURCES:
610 	case DP_POWER_DOWN_PHY:
611 	case DP_POWER_UP_PHY:
612 		P("port=%d\n", req->u.port_num.port_number);
613 		break;
614 	case DP_ALLOCATE_PAYLOAD:
615 		P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
616 		  req->u.allocate_payload.port_number,
617 		  req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
618 		  req->u.allocate_payload.number_sdp_streams,
619 		  req->u.allocate_payload.number_sdp_streams,
620 		  req->u.allocate_payload.sdp_stream_sink);
621 		break;
622 	case DP_QUERY_PAYLOAD:
623 		P("port=%d vcpi=%d\n",
624 		  req->u.query_payload.port_number,
625 		  req->u.query_payload.vcpi);
626 		break;
627 	case DP_REMOTE_DPCD_READ:
628 		P("port=%d dpcd_addr=%05x len=%d\n",
629 		  req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
630 		  req->u.dpcd_read.num_bytes);
631 		break;
632 	case DP_REMOTE_DPCD_WRITE:
633 		P("port=%d addr=%05x len=%d: %*ph\n",
634 		  req->u.dpcd_write.port_number,
635 		  req->u.dpcd_write.dpcd_address,
636 		  req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
637 		  req->u.dpcd_write.bytes);
638 		break;
639 	case DP_REMOTE_I2C_READ:
640 		P("port=%d num_tx=%d id=%d size=%d:\n",
641 		  req->u.i2c_read.port_number,
642 		  req->u.i2c_read.num_transactions,
643 		  req->u.i2c_read.read_i2c_device_id,
644 		  req->u.i2c_read.num_bytes_read);
645 
646 		indent++;
647 		for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
648 			const struct drm_dp_remote_i2c_read_tx *rtx =
649 				&req->u.i2c_read.transactions[i];
650 
651 			P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
652 			  i, rtx->i2c_dev_id, rtx->num_bytes,
653 			  rtx->no_stop_bit, rtx->i2c_transaction_delay,
654 			  rtx->num_bytes, rtx->bytes);
655 		}
656 		break;
657 	case DP_REMOTE_I2C_WRITE:
658 		P("port=%d id=%d size=%d: %*ph\n",
659 		  req->u.i2c_write.port_number,
660 		  req->u.i2c_write.write_i2c_device_id,
661 		  req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
662 		  req->u.i2c_write.bytes);
663 		break;
664 	case DP_QUERY_STREAM_ENC_STATUS:
665 		P("stream_id=%u client_id=%*ph stream_event=%x "
666 		  "valid_event=%d stream_behavior=%x valid_behavior=%d",
667 		  req->u.enc_status.stream_id,
668 		  (int)ARRAY_SIZE(req->u.enc_status.client_id),
669 		  req->u.enc_status.client_id, req->u.enc_status.stream_event,
670 		  req->u.enc_status.valid_stream_event,
671 		  req->u.enc_status.stream_behavior,
672 		  req->u.enc_status.valid_stream_behavior);
673 		break;
674 	default:
675 		P("???\n");
676 		break;
677 	}
678 #undef P
679 }
680 EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
681 
682 static inline void
drm_dp_mst_dump_sideband_msg_tx(struct drm_printer * p,const struct drm_dp_sideband_msg_tx * txmsg)683 drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
684 				const struct drm_dp_sideband_msg_tx *txmsg)
685 {
686 	struct drm_dp_sideband_msg_req_body req;
687 	char buf[64];
688 	int ret;
689 	int i;
690 
691 	drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
692 			      sizeof(buf));
693 	drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
694 		   txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
695 		   drm_dp_mst_sideband_tx_state_str(txmsg->state),
696 		   txmsg->path_msg, buf);
697 
698 	ret = drm_dp_decode_sideband_req(txmsg, &req);
699 	if (ret) {
700 		drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
701 		return;
702 	}
703 	drm_dp_dump_sideband_msg_req_body(&req, 1, p);
704 
705 	switch (req.req_type) {
706 	case DP_REMOTE_DPCD_WRITE:
707 		kfree(req.u.dpcd_write.bytes);
708 		break;
709 	case DP_REMOTE_I2C_READ:
710 		for (i = 0; i < req.u.i2c_read.num_transactions; i++)
711 			kfree(req.u.i2c_read.transactions[i].bytes);
712 		break;
713 	case DP_REMOTE_I2C_WRITE:
714 		kfree(req.u.i2c_write.bytes);
715 		break;
716 	}
717 }
718 
drm_dp_crc_sideband_chunk_req(u8 * msg,u8 len)719 static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
720 {
721 	u8 crc4;
722 
723 	crc4 = drm_dp_msg_data_crc4(msg, len);
724 	msg[len] = crc4;
725 }
726 
drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body * rep,struct drm_dp_sideband_msg_tx * raw)727 static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
728 					 struct drm_dp_sideband_msg_tx *raw)
729 {
730 	int idx = 0;
731 	u8 *buf = raw->msg;
732 
733 	buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
734 
735 	raw->cur_len = idx;
736 }
737 
drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx * msg,struct drm_dp_sideband_msg_hdr * hdr,u8 hdrlen)738 static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
739 					  struct drm_dp_sideband_msg_hdr *hdr,
740 					  u8 hdrlen)
741 {
742 	/*
743 	 * ignore out-of-order messages or messages that are part of a
744 	 * failed transaction
745 	 */
746 	if (!hdr->somt && !msg->have_somt)
747 		return false;
748 
749 	/* get length contained in this portion */
750 	msg->curchunk_idx = 0;
751 	msg->curchunk_len = hdr->msg_len;
752 	msg->curchunk_hdrlen = hdrlen;
753 
754 	/* we have already gotten an somt - don't bother parsing */
755 	if (hdr->somt && msg->have_somt)
756 		return false;
757 
758 	if (hdr->somt) {
759 		memcpy(&msg->initial_hdr, hdr,
760 		       sizeof(struct drm_dp_sideband_msg_hdr));
761 		msg->have_somt = true;
762 	}
763 	if (hdr->eomt)
764 		msg->have_eomt = true;
765 
766 	return true;
767 }
768 
769 /* this adds a chunk of msg to the builder to get the final msg */
drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx * msg,u8 * replybuf,u8 replybuflen)770 static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
771 					   u8 *replybuf, u8 replybuflen)
772 {
773 	u8 crc4;
774 
775 	memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
776 	msg->curchunk_idx += replybuflen;
777 
778 	if (msg->curchunk_idx >= msg->curchunk_len) {
779 		/* do CRC */
780 		crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
781 		if (crc4 != msg->chunk[msg->curchunk_len - 1])
782 			print_hex_dump(KERN_DEBUG, "wrong crc",
783 				       DUMP_PREFIX_NONE, 16, 1,
784 				       msg->chunk,  msg->curchunk_len, false);
785 		/* copy chunk into bigger msg */
786 		memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
787 		msg->curlen += msg->curchunk_len - 1;
788 	}
789 	return true;
790 }
791 
drm_dp_sideband_parse_link_address(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)792 static bool drm_dp_sideband_parse_link_address(struct drm_dp_sideband_msg_rx *raw,
793 					       struct drm_dp_sideband_msg_reply_body *repmsg)
794 {
795 	int idx = 1;
796 	int i;
797 
798 	memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
799 	idx += 16;
800 	repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
801 	idx++;
802 	if (idx > raw->curlen)
803 		goto fail_len;
804 	for (i = 0; i < repmsg->u.link_addr.nports; i++) {
805 		if (raw->msg[idx] & 0x80)
806 			repmsg->u.link_addr.ports[i].input_port = 1;
807 
808 		repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
809 		repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
810 
811 		idx++;
812 		if (idx > raw->curlen)
813 			goto fail_len;
814 		repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
815 		repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
816 		if (repmsg->u.link_addr.ports[i].input_port == 0)
817 			repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
818 		idx++;
819 		if (idx > raw->curlen)
820 			goto fail_len;
821 		if (repmsg->u.link_addr.ports[i].input_port == 0) {
822 			repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
823 			idx++;
824 			if (idx > raw->curlen)
825 				goto fail_len;
826 			memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
827 			idx += 16;
828 			if (idx > raw->curlen)
829 				goto fail_len;
830 			repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
831 			repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
832 			idx++;
833 
834 		}
835 		if (idx > raw->curlen)
836 			goto fail_len;
837 	}
838 
839 	return true;
840 fail_len:
841 	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
842 	return false;
843 }
844 
drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)845 static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
846 						   struct drm_dp_sideband_msg_reply_body *repmsg)
847 {
848 	int idx = 1;
849 
850 	repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
851 	idx++;
852 	if (idx > raw->curlen)
853 		goto fail_len;
854 	repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
855 	idx++;
856 	if (idx > raw->curlen)
857 		goto fail_len;
858 
859 	memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
860 	return true;
861 fail_len:
862 	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
863 	return false;
864 }
865 
drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)866 static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
867 						      struct drm_dp_sideband_msg_reply_body *repmsg)
868 {
869 	int idx = 1;
870 
871 	repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
872 	idx++;
873 	if (idx > raw->curlen)
874 		goto fail_len;
875 	return true;
876 fail_len:
877 	DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
878 	return false;
879 }
880 
drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)881 static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
882 						      struct drm_dp_sideband_msg_reply_body *repmsg)
883 {
884 	int idx = 1;
885 
886 	repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
887 	idx++;
888 	if (idx > raw->curlen)
889 		goto fail_len;
890 	repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
891 	idx++;
892 	/* TODO check */
893 	memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
894 	return true;
895 fail_len:
896 	DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
897 	return false;
898 }
899 
drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)900 static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
901 							  struct drm_dp_sideband_msg_reply_body *repmsg)
902 {
903 	int idx = 1;
904 
905 	repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
906 	repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
907 	idx++;
908 	if (idx > raw->curlen)
909 		goto fail_len;
910 	repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
911 	idx += 2;
912 	if (idx > raw->curlen)
913 		goto fail_len;
914 	repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
915 	idx += 2;
916 	if (idx > raw->curlen)
917 		goto fail_len;
918 	return true;
919 fail_len:
920 	DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
921 	return false;
922 }
923 
drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)924 static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
925 							  struct drm_dp_sideband_msg_reply_body *repmsg)
926 {
927 	int idx = 1;
928 
929 	repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
930 	idx++;
931 	if (idx > raw->curlen)
932 		goto fail_len;
933 	repmsg->u.allocate_payload.vcpi = raw->msg[idx];
934 	idx++;
935 	if (idx > raw->curlen)
936 		goto fail_len;
937 	repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
938 	idx += 2;
939 	if (idx > raw->curlen)
940 		goto fail_len;
941 	return true;
942 fail_len:
943 	DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
944 	return false;
945 }
946 
drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)947 static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
948 						    struct drm_dp_sideband_msg_reply_body *repmsg)
949 {
950 	int idx = 1;
951 
952 	repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
953 	idx++;
954 	if (idx > raw->curlen)
955 		goto fail_len;
956 	repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
957 	idx += 2;
958 	if (idx > raw->curlen)
959 		goto fail_len;
960 	return true;
961 fail_len:
962 	DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
963 	return false;
964 }
965 
drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)966 static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
967 						       struct drm_dp_sideband_msg_reply_body *repmsg)
968 {
969 	int idx = 1;
970 
971 	repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
972 	idx++;
973 	if (idx > raw->curlen) {
974 		DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
975 			      idx, raw->curlen);
976 		return false;
977 	}
978 	return true;
979 }
980 
981 static bool
drm_dp_sideband_parse_query_stream_enc_status(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * repmsg)982 drm_dp_sideband_parse_query_stream_enc_status(
983 				struct drm_dp_sideband_msg_rx *raw,
984 				struct drm_dp_sideband_msg_reply_body *repmsg)
985 {
986 	struct drm_dp_query_stream_enc_status_ack_reply *reply;
987 
988 	reply = &repmsg->u.enc_status;
989 
990 	reply->stream_id = raw->msg[3];
991 
992 	reply->reply_signed = raw->msg[2] & BIT(0);
993 
994 	/*
995 	 * NOTE: It's my impression from reading the spec that the below parsing
996 	 * is correct. However I noticed while testing with an HDCP 1.4 display
997 	 * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
998 	 * would expect both bits to be set. So keep the parsing following the
999 	 * spec, but beware reality might not match the spec (at least for some
1000 	 * configurations).
1001 	 */
1002 	reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1003 	reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1004 
1005 	reply->query_capable_device_present = raw->msg[2] & BIT(5);
1006 	reply->legacy_device_present = raw->msg[2] & BIT(6);
1007 	reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1008 
1009 	reply->auth_completed = !!(raw->msg[1] & BIT(3));
1010 	reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1011 	reply->repeater_present = !!(raw->msg[1] & BIT(5));
1012 	reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1013 
1014 	return true;
1015 }
1016 
drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_reply_body * msg)1017 static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
1018 					struct drm_dp_sideband_msg_reply_body *msg)
1019 {
1020 	memset(msg, 0, sizeof(*msg));
1021 	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1022 	msg->req_type = (raw->msg[0] & 0x7f);
1023 
1024 	if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1025 		memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1026 		msg->u.nak.reason = raw->msg[17];
1027 		msg->u.nak.nak_data = raw->msg[18];
1028 		return false;
1029 	}
1030 
1031 	switch (msg->req_type) {
1032 	case DP_LINK_ADDRESS:
1033 		return drm_dp_sideband_parse_link_address(raw, msg);
1034 	case DP_QUERY_PAYLOAD:
1035 		return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1036 	case DP_REMOTE_DPCD_READ:
1037 		return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1038 	case DP_REMOTE_DPCD_WRITE:
1039 		return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1040 	case DP_REMOTE_I2C_READ:
1041 		return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1042 	case DP_REMOTE_I2C_WRITE:
1043 		return true; /* since there's nothing to parse */
1044 	case DP_ENUM_PATH_RESOURCES:
1045 		return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1046 	case DP_ALLOCATE_PAYLOAD:
1047 		return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1048 	case DP_POWER_DOWN_PHY:
1049 	case DP_POWER_UP_PHY:
1050 		return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1051 	case DP_CLEAR_PAYLOAD_ID_TABLE:
1052 		return true; /* since there's nothing to parse */
1053 	case DP_QUERY_STREAM_ENC_STATUS:
1054 		return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1055 	default:
1056 		DRM_ERROR("Got unknown reply 0x%02x (%s)\n", msg->req_type,
1057 			  drm_dp_mst_req_type_str(msg->req_type));
1058 		return false;
1059 	}
1060 }
1061 
drm_dp_sideband_parse_connection_status_notify(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_req_body * msg)1062 static bool drm_dp_sideband_parse_connection_status_notify(struct drm_dp_sideband_msg_rx *raw,
1063 							   struct drm_dp_sideband_msg_req_body *msg)
1064 {
1065 	int idx = 1;
1066 
1067 	msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1068 	idx++;
1069 	if (idx > raw->curlen)
1070 		goto fail_len;
1071 
1072 	memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1073 	idx += 16;
1074 	if (idx > raw->curlen)
1075 		goto fail_len;
1076 
1077 	msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1078 	msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1079 	msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1080 	msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1081 	msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1082 	idx++;
1083 	return true;
1084 fail_len:
1085 	DRM_DEBUG_KMS("connection status reply parse length fail %d %d\n", idx, raw->curlen);
1086 	return false;
1087 }
1088 
drm_dp_sideband_parse_resource_status_notify(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_req_body * msg)1089 static bool drm_dp_sideband_parse_resource_status_notify(struct drm_dp_sideband_msg_rx *raw,
1090 							   struct drm_dp_sideband_msg_req_body *msg)
1091 {
1092 	int idx = 1;
1093 
1094 	msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1095 	idx++;
1096 	if (idx > raw->curlen)
1097 		goto fail_len;
1098 
1099 	memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1100 	idx += 16;
1101 	if (idx > raw->curlen)
1102 		goto fail_len;
1103 
1104 	msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1105 	idx++;
1106 	return true;
1107 fail_len:
1108 	DRM_DEBUG_KMS("resource status reply parse length fail %d %d\n", idx, raw->curlen);
1109 	return false;
1110 }
1111 
drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx * raw,struct drm_dp_sideband_msg_req_body * msg)1112 static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
1113 				      struct drm_dp_sideband_msg_req_body *msg)
1114 {
1115 	memset(msg, 0, sizeof(*msg));
1116 	msg->req_type = (raw->msg[0] & 0x7f);
1117 
1118 	switch (msg->req_type) {
1119 	case DP_CONNECTION_STATUS_NOTIFY:
1120 		return drm_dp_sideband_parse_connection_status_notify(raw, msg);
1121 	case DP_RESOURCE_STATUS_NOTIFY:
1122 		return drm_dp_sideband_parse_resource_status_notify(raw, msg);
1123 	default:
1124 		DRM_ERROR("Got unknown request 0x%02x (%s)\n", msg->req_type,
1125 			  drm_dp_mst_req_type_str(msg->req_type));
1126 		return false;
1127 	}
1128 }
1129 
build_dpcd_write(struct drm_dp_sideband_msg_tx * msg,u8 port_num,u32 offset,u8 num_bytes,u8 * bytes)1130 static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1131 			     u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1132 {
1133 	struct drm_dp_sideband_msg_req_body req;
1134 
1135 	req.req_type = DP_REMOTE_DPCD_WRITE;
1136 	req.u.dpcd_write.port_number = port_num;
1137 	req.u.dpcd_write.dpcd_address = offset;
1138 	req.u.dpcd_write.num_bytes = num_bytes;
1139 	req.u.dpcd_write.bytes = bytes;
1140 	drm_dp_encode_sideband_req(&req, msg);
1141 }
1142 
build_link_address(struct drm_dp_sideband_msg_tx * msg)1143 static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1144 {
1145 	struct drm_dp_sideband_msg_req_body req;
1146 
1147 	req.req_type = DP_LINK_ADDRESS;
1148 	drm_dp_encode_sideband_req(&req, msg);
1149 }
1150 
build_clear_payload_id_table(struct drm_dp_sideband_msg_tx * msg)1151 static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1152 {
1153 	struct drm_dp_sideband_msg_req_body req;
1154 
1155 	req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1156 	drm_dp_encode_sideband_req(&req, msg);
1157 }
1158 
build_enum_path_resources(struct drm_dp_sideband_msg_tx * msg,int port_num)1159 static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1160 				     int port_num)
1161 {
1162 	struct drm_dp_sideband_msg_req_body req;
1163 
1164 	req.req_type = DP_ENUM_PATH_RESOURCES;
1165 	req.u.port_num.port_number = port_num;
1166 	drm_dp_encode_sideband_req(&req, msg);
1167 	msg->path_msg = true;
1168 	return 0;
1169 }
1170 
build_allocate_payload(struct drm_dp_sideband_msg_tx * msg,int port_num,u8 vcpi,uint16_t pbn,u8 number_sdp_streams,u8 * sdp_stream_sink)1171 static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1172 				   int port_num,
1173 				   u8 vcpi, uint16_t pbn,
1174 				   u8 number_sdp_streams,
1175 				   u8 *sdp_stream_sink)
1176 {
1177 	struct drm_dp_sideband_msg_req_body req;
1178 
1179 	memset(&req, 0, sizeof(req));
1180 	req.req_type = DP_ALLOCATE_PAYLOAD;
1181 	req.u.allocate_payload.port_number = port_num;
1182 	req.u.allocate_payload.vcpi = vcpi;
1183 	req.u.allocate_payload.pbn = pbn;
1184 	req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1185 	memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1186 		   number_sdp_streams);
1187 	drm_dp_encode_sideband_req(&req, msg);
1188 	msg->path_msg = true;
1189 }
1190 
build_power_updown_phy(struct drm_dp_sideband_msg_tx * msg,int port_num,bool power_up)1191 static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1192 				   int port_num, bool power_up)
1193 {
1194 	struct drm_dp_sideband_msg_req_body req;
1195 
1196 	if (power_up)
1197 		req.req_type = DP_POWER_UP_PHY;
1198 	else
1199 		req.req_type = DP_POWER_DOWN_PHY;
1200 
1201 	req.u.port_num.port_number = port_num;
1202 	drm_dp_encode_sideband_req(&req, msg);
1203 	msg->path_msg = true;
1204 }
1205 
1206 static int
build_query_stream_enc_status(struct drm_dp_sideband_msg_tx * msg,u8 stream_id,u8 * q_id)1207 build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1208 			      u8 *q_id)
1209 {
1210 	struct drm_dp_sideband_msg_req_body req;
1211 
1212 	req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1213 	req.u.enc_status.stream_id = stream_id;
1214 	memcpy(req.u.enc_status.client_id, q_id,
1215 	       sizeof(req.u.enc_status.client_id));
1216 	req.u.enc_status.stream_event = 0;
1217 	req.u.enc_status.valid_stream_event = false;
1218 	req.u.enc_status.stream_behavior = 0;
1219 	req.u.enc_status.valid_stream_behavior = false;
1220 
1221 	drm_dp_encode_sideband_req(&req, msg);
1222 	return 0;
1223 }
1224 
drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_vcpi * vcpi)1225 static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1226 					struct drm_dp_vcpi *vcpi)
1227 {
1228 	int ret, vcpi_ret;
1229 
1230 	mutex_lock(&mgr->payload_lock);
1231 	ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
1232 	if (ret > mgr->max_payloads) {
1233 		ret = -EINVAL;
1234 		DRM_DEBUG_KMS("out of payload ids %d\n", ret);
1235 		goto out_unlock;
1236 	}
1237 
1238 	vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
1239 	if (vcpi_ret > mgr->max_payloads) {
1240 		ret = -EINVAL;
1241 		DRM_DEBUG_KMS("out of vcpi ids %d\n", ret);
1242 		goto out_unlock;
1243 	}
1244 
1245 	set_bit(ret, &mgr->payload_mask);
1246 	set_bit(vcpi_ret, &mgr->vcpi_mask);
1247 	vcpi->vcpi = vcpi_ret + 1;
1248 	mgr->proposed_vcpis[ret - 1] = vcpi;
1249 out_unlock:
1250 	mutex_unlock(&mgr->payload_lock);
1251 	return ret;
1252 }
1253 
drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr * mgr,int vcpi)1254 static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1255 				      int vcpi)
1256 {
1257 	int i;
1258 
1259 	if (vcpi == 0)
1260 		return;
1261 
1262 	mutex_lock(&mgr->payload_lock);
1263 	DRM_DEBUG_KMS("putting payload %d\n", vcpi);
1264 	clear_bit(vcpi - 1, &mgr->vcpi_mask);
1265 
1266 	for (i = 0; i < mgr->max_payloads; i++) {
1267 		if (mgr->proposed_vcpis[i] &&
1268 		    mgr->proposed_vcpis[i]->vcpi == vcpi) {
1269 			mgr->proposed_vcpis[i] = NULL;
1270 			clear_bit(i + 1, &mgr->payload_mask);
1271 		}
1272 	}
1273 	mutex_unlock(&mgr->payload_lock);
1274 }
1275 
check_txmsg_state(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_tx * txmsg)1276 static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1277 			      struct drm_dp_sideband_msg_tx *txmsg)
1278 {
1279 	unsigned int state;
1280 
1281 	/*
1282 	 * All updates to txmsg->state are protected by mgr->qlock, and the two
1283 	 * cases we check here are terminal states. For those the barriers
1284 	 * provided by the wake_up/wait_event pair are enough.
1285 	 */
1286 	state = READ_ONCE(txmsg->state);
1287 	return (state == DRM_DP_SIDEBAND_TX_RX ||
1288 		state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1289 }
1290 
drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch * mstb,struct drm_dp_sideband_msg_tx * txmsg)1291 static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1292 				    struct drm_dp_sideband_msg_tx *txmsg)
1293 {
1294 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1295 	unsigned long wait_timeout = msecs_to_jiffies(4000);
1296 	unsigned long wait_expires = jiffies + wait_timeout;
1297 	int ret;
1298 
1299 	for (;;) {
1300 		/*
1301 		 * If the driver provides a way for this, change to
1302 		 * poll-waiting for the MST reply interrupt if we didn't receive
1303 		 * it for 50 msec. This would cater for cases where the HPD
1304 		 * pulse signal got lost somewhere, even though the sink raised
1305 		 * the corresponding MST interrupt correctly. One example is the
1306 		 * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1307 		 * filters out short pulses with a duration less than ~540 usec.
1308 		 *
1309 		 * The poll period is 50 msec to avoid missing an interrupt
1310 		 * after the sink has cleared it (after a 110msec timeout
1311 		 * since it raised the interrupt).
1312 		 */
1313 		ret = wait_event_timeout(mgr->tx_waitq,
1314 					 check_txmsg_state(mgr, txmsg),
1315 					 mgr->cbs->poll_hpd_irq ?
1316 						msecs_to_jiffies(50) :
1317 						wait_timeout);
1318 
1319 		if (ret || !mgr->cbs->poll_hpd_irq ||
1320 		    time_after(jiffies, wait_expires))
1321 			break;
1322 
1323 		mgr->cbs->poll_hpd_irq(mgr);
1324 	}
1325 
1326 	mutex_lock(&mgr->qlock);
1327 	if (ret > 0) {
1328 		if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1329 			ret = -EIO;
1330 			goto out;
1331 		}
1332 	} else {
1333 		DRM_DEBUG_KMS("timedout msg send %p %d %d\n", txmsg, txmsg->state, txmsg->seqno);
1334 
1335 		/* dump some state */
1336 		ret = -EIO;
1337 
1338 		/* remove from q */
1339 		if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1340 		    txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1341 		    txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1342 			list_del(&txmsg->next);
1343 	}
1344 out:
1345 	if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1346 		struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1347 
1348 		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1349 	}
1350 	mutex_unlock(&mgr->qlock);
1351 
1352 	drm_dp_mst_kick_tx(mgr);
1353 	return ret;
1354 }
1355 
drm_dp_add_mst_branch_device(u8 lct,u8 * rad)1356 static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1357 {
1358 	struct drm_dp_mst_branch *mstb;
1359 
1360 	mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1361 	if (!mstb)
1362 		return NULL;
1363 
1364 	mstb->lct = lct;
1365 	if (lct > 1)
1366 		memcpy(mstb->rad, rad, lct / 2);
1367 	INIT_LIST_HEAD(&mstb->ports);
1368 	kref_init(&mstb->topology_kref);
1369 	kref_init(&mstb->malloc_kref);
1370 	return mstb;
1371 }
1372 
drm_dp_free_mst_branch_device(struct kref * kref)1373 static void drm_dp_free_mst_branch_device(struct kref *kref)
1374 {
1375 	struct drm_dp_mst_branch *mstb =
1376 		container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1377 
1378 	if (mstb->port_parent)
1379 		drm_dp_mst_put_port_malloc(mstb->port_parent);
1380 
1381 	kfree(mstb);
1382 }
1383 
1384 /**
1385  * DOC: Branch device and port refcounting
1386  *
1387  * Topology refcount overview
1388  * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1389  *
1390  * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1391  * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1392  * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1393  *
1394  * Topology refcounts are not exposed to drivers, and are handled internally
1395  * by the DP MST helpers. The helpers use them in order to prevent the
1396  * in-memory topology state from being changed in the middle of critical
1397  * operations like changing the internal state of payload allocations. This
1398  * means each branch and port will be considered to be connected to the rest
1399  * of the topology until its topology refcount reaches zero. Additionally,
1400  * for ports this means that their associated &struct drm_connector will stay
1401  * registered with userspace until the port's refcount reaches 0.
1402  *
1403  * Malloc refcount overview
1404  * ~~~~~~~~~~~~~~~~~~~~~~~~
1405  *
1406  * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1407  * drm_dp_mst_branch allocated even after all of its topology references have
1408  * been dropped, so that the driver or MST helpers can safely access each
1409  * branch's last known state before it was disconnected from the topology.
1410  * When the malloc refcount of a port or branch reaches 0, the memory
1411  * allocation containing the &struct drm_dp_mst_branch or &struct
1412  * drm_dp_mst_port respectively will be freed.
1413  *
1414  * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1415  * to drivers. As of writing this documentation, there are no drivers that
1416  * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1417  * helpers. Exposing this API to drivers in a race-free manner would take more
1418  * tweaking of the refcounting scheme, however patches are welcome provided
1419  * there is a legitimate driver usecase for this.
1420  *
1421  * Refcount relationships in a topology
1422  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1423  *
1424  * Let's take a look at why the relationship between topology and malloc
1425  * refcounts is designed the way it is.
1426  *
1427  * .. kernel-figure:: dp-mst/topology-figure-1.dot
1428  *
1429  *    An example of topology and malloc refs in a DP MST topology with two
1430  *    active payloads. Topology refcount increments are indicated by solid
1431  *    lines, and malloc refcount increments are indicated by dashed lines.
1432  *    Each starts from the branch which incremented the refcount, and ends at
1433  *    the branch to which the refcount belongs to, i.e. the arrow points the
1434  *    same way as the C pointers used to reference a structure.
1435  *
1436  * As you can see in the above figure, every branch increments the topology
1437  * refcount of its children, and increments the malloc refcount of its
1438  * parent. Additionally, every payload increments the malloc refcount of its
1439  * assigned port by 1.
1440  *
1441  * So, what would happen if MSTB #3 from the above figure was unplugged from
1442  * the system, but the driver hadn't yet removed payload #2 from port #3? The
1443  * topology would start to look like the figure below.
1444  *
1445  * .. kernel-figure:: dp-mst/topology-figure-2.dot
1446  *
1447  *    Ports and branch devices which have been released from memory are
1448  *    colored grey, and references which have been removed are colored red.
1449  *
1450  * Whenever a port or branch device's topology refcount reaches zero, it will
1451  * decrement the topology refcounts of all its children, the malloc refcount
1452  * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1453  * #4, this means they both have been disconnected from the topology and freed
1454  * from memory. But, because payload #2 is still holding a reference to port
1455  * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1456  * is still accessible from memory. This also means port #3 has not yet
1457  * decremented the malloc refcount of MSTB #3, so its &struct
1458  * drm_dp_mst_branch will also stay allocated in memory until port #3's
1459  * malloc refcount reaches 0.
1460  *
1461  * This relationship is necessary because in order to release payload #2, we
1462  * need to be able to figure out the last relative of port #3 that's still
1463  * connected to the topology. In this case, we would travel up the topology as
1464  * shown below.
1465  *
1466  * .. kernel-figure:: dp-mst/topology-figure-3.dot
1467  *
1468  * And finally, remove payload #2 by communicating with port #2 through
1469  * sideband transactions.
1470  */
1471 
1472 /**
1473  * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1474  * device
1475  * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1476  *
1477  * Increments &drm_dp_mst_branch.malloc_kref. When
1478  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1479  * will be released and @mstb may no longer be used.
1480  *
1481  * See also: drm_dp_mst_put_mstb_malloc()
1482  */
1483 static void
drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch * mstb)1484 drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1485 {
1486 	kref_get(&mstb->malloc_kref);
1487 	DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1488 }
1489 
1490 /**
1491  * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1492  * device
1493  * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1494  *
1495  * Decrements &drm_dp_mst_branch.malloc_kref. When
1496  * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1497  * will be released and @mstb may no longer be used.
1498  *
1499  * See also: drm_dp_mst_get_mstb_malloc()
1500  */
1501 static void
drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch * mstb)1502 drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1503 {
1504 	DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1505 	kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1506 }
1507 
drm_dp_free_mst_port(struct kref * kref)1508 static void drm_dp_free_mst_port(struct kref *kref)
1509 {
1510 	struct drm_dp_mst_port *port =
1511 		container_of(kref, struct drm_dp_mst_port, malloc_kref);
1512 
1513 	drm_dp_mst_put_mstb_malloc(port->parent);
1514 	kfree(port);
1515 }
1516 
1517 /**
1518  * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1519  * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1520  *
1521  * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1522  * reaches 0, the memory allocation for @port will be released and @port may
1523  * no longer be used.
1524  *
1525  * Because @port could potentially be freed at any time by the DP MST helpers
1526  * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1527  * function, drivers that which to make use of &struct drm_dp_mst_port should
1528  * ensure that they grab at least one main malloc reference to their MST ports
1529  * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1530  * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1531  *
1532  * See also: drm_dp_mst_put_port_malloc()
1533  */
1534 void
drm_dp_mst_get_port_malloc(struct drm_dp_mst_port * port)1535 drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1536 {
1537 	kref_get(&port->malloc_kref);
1538 	DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref));
1539 }
1540 EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1541 
1542 /**
1543  * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1544  * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1545  *
1546  * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1547  * reaches 0, the memory allocation for @port will be released and @port may
1548  * no longer be used.
1549  *
1550  * See also: drm_dp_mst_get_port_malloc()
1551  */
1552 void
drm_dp_mst_put_port_malloc(struct drm_dp_mst_port * port)1553 drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1554 {
1555 	DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1556 	kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1557 }
1558 EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1559 
1560 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1561 
1562 #define STACK_DEPTH 8
1563 
1564 static noinline void
__topology_ref_save(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_ref_history * history,enum drm_dp_mst_topology_ref_type type)1565 __topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1566 		    struct drm_dp_mst_topology_ref_history *history,
1567 		    enum drm_dp_mst_topology_ref_type type)
1568 {
1569 	struct drm_dp_mst_topology_ref_entry *entry = NULL;
1570 	depot_stack_handle_t backtrace;
1571 	ulong stack_entries[STACK_DEPTH];
1572 	uint n;
1573 	int i;
1574 
1575 	n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1576 	backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1577 	if (!backtrace)
1578 		return;
1579 
1580 	/* Try to find an existing entry for this backtrace */
1581 	for (i = 0; i < history->len; i++) {
1582 		if (history->entries[i].backtrace == backtrace) {
1583 			entry = &history->entries[i];
1584 			break;
1585 		}
1586 	}
1587 
1588 	/* Otherwise add one */
1589 	if (!entry) {
1590 		struct drm_dp_mst_topology_ref_entry *new;
1591 		int new_len = history->len + 1;
1592 
1593 		new = krealloc(history->entries, sizeof(*new) * new_len,
1594 			       GFP_KERNEL);
1595 		if (!new)
1596 			return;
1597 
1598 		entry = &new[history->len];
1599 		history->len = new_len;
1600 		history->entries = new;
1601 
1602 		entry->backtrace = backtrace;
1603 		entry->type = type;
1604 		entry->count = 0;
1605 	}
1606 	entry->count++;
1607 	entry->ts_nsec = ktime_get_ns();
1608 }
1609 
1610 static int
topology_ref_history_cmp(const void * a,const void * b)1611 topology_ref_history_cmp(const void *a, const void *b)
1612 {
1613 	const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1614 
1615 	if (entry_a->ts_nsec > entry_b->ts_nsec)
1616 		return 1;
1617 	else if (entry_a->ts_nsec < entry_b->ts_nsec)
1618 		return -1;
1619 	else
1620 		return 0;
1621 }
1622 
1623 static inline const char *
topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)1624 topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1625 {
1626 	if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1627 		return "get";
1628 	else
1629 		return "put";
1630 }
1631 
1632 static void
__dump_topology_ref_history(struct drm_dp_mst_topology_ref_history * history,void * ptr,const char * type_str)1633 __dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1634 			    void *ptr, const char *type_str)
1635 {
1636 	struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1637 	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1638 	int i;
1639 
1640 	if (!buf)
1641 		return;
1642 
1643 	if (!history->len)
1644 		goto out;
1645 
1646 	/* First, sort the list so that it goes from oldest to newest
1647 	 * reference entry
1648 	 */
1649 	sort(history->entries, history->len, sizeof(*history->entries),
1650 	     topology_ref_history_cmp, NULL);
1651 
1652 	drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1653 		   type_str, ptr);
1654 
1655 	for (i = 0; i < history->len; i++) {
1656 		const struct drm_dp_mst_topology_ref_entry *entry =
1657 			&history->entries[i];
1658 		ulong *entries;
1659 		uint nr_entries;
1660 		u64 ts_nsec = entry->ts_nsec;
1661 		u32 rem_nsec = do_div(ts_nsec, 1000000000);
1662 
1663 		nr_entries = stack_depot_fetch(entry->backtrace, &entries);
1664 		stack_trace_snprint(buf, PAGE_SIZE, entries, nr_entries, 4);
1665 
1666 		drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1667 			   entry->count,
1668 			   topology_ref_type_to_str(entry->type),
1669 			   ts_nsec, rem_nsec / 1000, buf);
1670 	}
1671 
1672 	/* Now free the history, since this is the only time we expose it */
1673 	kfree(history->entries);
1674 out:
1675 	kfree(buf);
1676 }
1677 
1678 static __always_inline void
drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch * mstb)1679 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1680 {
1681 	__dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1682 				    "MSTB");
1683 }
1684 
1685 static __always_inline void
drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port * port)1686 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1687 {
1688 	__dump_topology_ref_history(&port->topology_ref_history, port,
1689 				    "Port");
1690 }
1691 
1692 static __always_inline void
save_mstb_topology_ref(struct drm_dp_mst_branch * mstb,enum drm_dp_mst_topology_ref_type type)1693 save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1694 		       enum drm_dp_mst_topology_ref_type type)
1695 {
1696 	__topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1697 }
1698 
1699 static __always_inline void
save_port_topology_ref(struct drm_dp_mst_port * port,enum drm_dp_mst_topology_ref_type type)1700 save_port_topology_ref(struct drm_dp_mst_port *port,
1701 		       enum drm_dp_mst_topology_ref_type type)
1702 {
1703 	__topology_ref_save(port->mgr, &port->topology_ref_history, type);
1704 }
1705 
1706 static inline void
topology_ref_history_lock(struct drm_dp_mst_topology_mgr * mgr)1707 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1708 {
1709 	mutex_lock(&mgr->topology_ref_history_lock);
1710 }
1711 
1712 static inline void
topology_ref_history_unlock(struct drm_dp_mst_topology_mgr * mgr)1713 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1714 {
1715 	mutex_unlock(&mgr->topology_ref_history_lock);
1716 }
1717 #else
1718 static inline void
topology_ref_history_lock(struct drm_dp_mst_topology_mgr * mgr)1719 topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1720 static inline void
topology_ref_history_unlock(struct drm_dp_mst_topology_mgr * mgr)1721 topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1722 static inline void
drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch * mstb)1723 drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1724 static inline void
drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port * port)1725 drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1726 #define save_mstb_topology_ref(mstb, type)
1727 #define save_port_topology_ref(port, type)
1728 #endif
1729 
drm_dp_destroy_mst_branch_device(struct kref * kref)1730 static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1731 {
1732 	struct drm_dp_mst_branch *mstb =
1733 		container_of(kref, struct drm_dp_mst_branch, topology_kref);
1734 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1735 
1736 	drm_dp_mst_dump_mstb_topology_history(mstb);
1737 
1738 	INIT_LIST_HEAD(&mstb->destroy_next);
1739 
1740 	/*
1741 	 * This can get called under mgr->mutex, so we need to perform the
1742 	 * actual destruction of the mstb in another worker
1743 	 */
1744 	mutex_lock(&mgr->delayed_destroy_lock);
1745 	list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1746 	mutex_unlock(&mgr->delayed_destroy_lock);
1747 	queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1748 }
1749 
1750 /**
1751  * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1752  * branch device unless it's zero
1753  * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1754  *
1755  * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1756  * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1757  * reached 0). Holding a topology reference implies that a malloc reference
1758  * will be held to @mstb as long as the user holds the topology reference.
1759  *
1760  * Care should be taken to ensure that the user has at least one malloc
1761  * reference to @mstb. If you already have a topology reference to @mstb, you
1762  * should use drm_dp_mst_topology_get_mstb() instead.
1763  *
1764  * See also:
1765  * drm_dp_mst_topology_get_mstb()
1766  * drm_dp_mst_topology_put_mstb()
1767  *
1768  * Returns:
1769  * * 1: A topology reference was grabbed successfully
1770  * * 0: @port is no longer in the topology, no reference was grabbed
1771  */
1772 static int __must_check
drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch * mstb)1773 drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1774 {
1775 	int ret;
1776 
1777 	topology_ref_history_lock(mstb->mgr);
1778 	ret = kref_get_unless_zero(&mstb->topology_kref);
1779 	if (ret) {
1780 		DRM_DEBUG("mstb %p (%d)\n",
1781 			  mstb, kref_read(&mstb->topology_kref));
1782 		save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1783 	}
1784 
1785 	topology_ref_history_unlock(mstb->mgr);
1786 
1787 	return ret;
1788 }
1789 
1790 /**
1791  * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1792  * branch device
1793  * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1794  *
1795  * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1796  * not it's already reached 0. This is only valid to use in scenarios where
1797  * you are already guaranteed to have at least one active topology reference
1798  * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1799  *
1800  * See also:
1801  * drm_dp_mst_topology_try_get_mstb()
1802  * drm_dp_mst_topology_put_mstb()
1803  */
drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch * mstb)1804 static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1805 {
1806 	topology_ref_history_lock(mstb->mgr);
1807 
1808 	save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1809 	WARN_ON(kref_read(&mstb->topology_kref) == 0);
1810 	kref_get(&mstb->topology_kref);
1811 	DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1812 
1813 	topology_ref_history_unlock(mstb->mgr);
1814 }
1815 
1816 /**
1817  * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1818  * device
1819  * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1820  *
1821  * Releases a topology reference from @mstb by decrementing
1822  * &drm_dp_mst_branch.topology_kref.
1823  *
1824  * See also:
1825  * drm_dp_mst_topology_try_get_mstb()
1826  * drm_dp_mst_topology_get_mstb()
1827  */
1828 static void
drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch * mstb)1829 drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1830 {
1831 	topology_ref_history_lock(mstb->mgr);
1832 
1833 	DRM_DEBUG("mstb %p (%d)\n",
1834 		  mstb, kref_read(&mstb->topology_kref) - 1);
1835 	save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1836 
1837 	topology_ref_history_unlock(mstb->mgr);
1838 	kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1839 }
1840 
drm_dp_destroy_port(struct kref * kref)1841 static void drm_dp_destroy_port(struct kref *kref)
1842 {
1843 	struct drm_dp_mst_port *port =
1844 		container_of(kref, struct drm_dp_mst_port, topology_kref);
1845 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1846 
1847 	drm_dp_mst_dump_port_topology_history(port);
1848 
1849 	/* There's nothing that needs locking to destroy an input port yet */
1850 	if (port->input) {
1851 		drm_dp_mst_put_port_malloc(port);
1852 		return;
1853 	}
1854 
1855 	kfree(port->cached_edid);
1856 
1857 	/*
1858 	 * we can't destroy the connector here, as we might be holding the
1859 	 * mode_config.mutex from an EDID retrieval
1860 	 */
1861 	mutex_lock(&mgr->delayed_destroy_lock);
1862 	list_add(&port->next, &mgr->destroy_port_list);
1863 	mutex_unlock(&mgr->delayed_destroy_lock);
1864 	queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1865 }
1866 
1867 /**
1868  * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1869  * port unless it's zero
1870  * @port: &struct drm_dp_mst_port to increment the topology refcount of
1871  *
1872  * Attempts to grab a topology reference to @port, if it hasn't yet been
1873  * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1874  * 0). Holding a topology reference implies that a malloc reference will be
1875  * held to @port as long as the user holds the topology reference.
1876  *
1877  * Care should be taken to ensure that the user has at least one malloc
1878  * reference to @port. If you already have a topology reference to @port, you
1879  * should use drm_dp_mst_topology_get_port() instead.
1880  *
1881  * See also:
1882  * drm_dp_mst_topology_get_port()
1883  * drm_dp_mst_topology_put_port()
1884  *
1885  * Returns:
1886  * * 1: A topology reference was grabbed successfully
1887  * * 0: @port is no longer in the topology, no reference was grabbed
1888  */
1889 static int __must_check
drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port * port)1890 drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1891 {
1892 	int ret;
1893 
1894 	topology_ref_history_lock(port->mgr);
1895 	ret = kref_get_unless_zero(&port->topology_kref);
1896 	if (ret) {
1897 		DRM_DEBUG("port %p (%d)\n",
1898 			  port, kref_read(&port->topology_kref));
1899 		save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1900 	}
1901 
1902 	topology_ref_history_unlock(port->mgr);
1903 	return ret;
1904 }
1905 
1906 /**
1907  * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1908  * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1909  *
1910  * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1911  * not it's already reached 0. This is only valid to use in scenarios where
1912  * you are already guaranteed to have at least one active topology reference
1913  * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1914  *
1915  * See also:
1916  * drm_dp_mst_topology_try_get_port()
1917  * drm_dp_mst_topology_put_port()
1918  */
drm_dp_mst_topology_get_port(struct drm_dp_mst_port * port)1919 static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1920 {
1921 	topology_ref_history_lock(port->mgr);
1922 
1923 	WARN_ON(kref_read(&port->topology_kref) == 0);
1924 	kref_get(&port->topology_kref);
1925 	DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->topology_kref));
1926 	save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1927 
1928 	topology_ref_history_unlock(port->mgr);
1929 }
1930 
1931 /**
1932  * drm_dp_mst_topology_put_port() - release a topology reference to a port
1933  * @port: The &struct drm_dp_mst_port to release the topology reference from
1934  *
1935  * Releases a topology reference from @port by decrementing
1936  * &drm_dp_mst_port.topology_kref.
1937  *
1938  * See also:
1939  * drm_dp_mst_topology_try_get_port()
1940  * drm_dp_mst_topology_get_port()
1941  */
drm_dp_mst_topology_put_port(struct drm_dp_mst_port * port)1942 static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1943 {
1944 	topology_ref_history_lock(port->mgr);
1945 
1946 	DRM_DEBUG("port %p (%d)\n",
1947 		  port, kref_read(&port->topology_kref) - 1);
1948 	save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1949 
1950 	topology_ref_history_unlock(port->mgr);
1951 	kref_put(&port->topology_kref, drm_dp_destroy_port);
1952 }
1953 
1954 static struct drm_dp_mst_branch *
drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_branch * to_find)1955 drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1956 					      struct drm_dp_mst_branch *to_find)
1957 {
1958 	struct drm_dp_mst_port *port;
1959 	struct drm_dp_mst_branch *rmstb;
1960 
1961 	if (to_find == mstb)
1962 		return mstb;
1963 
1964 	list_for_each_entry(port, &mstb->ports, next) {
1965 		if (port->mstb) {
1966 			rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1967 			    port->mstb, to_find);
1968 			if (rmstb)
1969 				return rmstb;
1970 		}
1971 	}
1972 	return NULL;
1973 }
1974 
1975 static struct drm_dp_mst_branch *
drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)1976 drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1977 				       struct drm_dp_mst_branch *mstb)
1978 {
1979 	struct drm_dp_mst_branch *rmstb = NULL;
1980 
1981 	mutex_lock(&mgr->lock);
1982 	if (mgr->mst_primary) {
1983 		rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1984 		    mgr->mst_primary, mstb);
1985 
1986 		if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1987 			rmstb = NULL;
1988 	}
1989 	mutex_unlock(&mgr->lock);
1990 	return rmstb;
1991 }
1992 
1993 static struct drm_dp_mst_port *
drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * to_find)1994 drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
1995 					      struct drm_dp_mst_port *to_find)
1996 {
1997 	struct drm_dp_mst_port *port, *mport;
1998 
1999 	list_for_each_entry(port, &mstb->ports, next) {
2000 		if (port == to_find)
2001 			return port;
2002 
2003 		if (port->mstb) {
2004 			mport = drm_dp_mst_topology_get_port_validated_locked(
2005 			    port->mstb, to_find);
2006 			if (mport)
2007 				return mport;
2008 		}
2009 	}
2010 	return NULL;
2011 }
2012 
2013 static struct drm_dp_mst_port *
drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)2014 drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
2015 				       struct drm_dp_mst_port *port)
2016 {
2017 	struct drm_dp_mst_port *rport = NULL;
2018 
2019 	mutex_lock(&mgr->lock);
2020 	if (mgr->mst_primary) {
2021 		rport = drm_dp_mst_topology_get_port_validated_locked(
2022 		    mgr->mst_primary, port);
2023 
2024 		if (rport && !drm_dp_mst_topology_try_get_port(rport))
2025 			rport = NULL;
2026 	}
2027 	mutex_unlock(&mgr->lock);
2028 	return rport;
2029 }
2030 
drm_dp_get_port(struct drm_dp_mst_branch * mstb,u8 port_num)2031 static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2032 {
2033 	struct drm_dp_mst_port *port;
2034 	int ret;
2035 
2036 	list_for_each_entry(port, &mstb->ports, next) {
2037 		if (port->port_num == port_num) {
2038 			ret = drm_dp_mst_topology_try_get_port(port);
2039 			return ret ? port : NULL;
2040 		}
2041 	}
2042 
2043 	return NULL;
2044 }
2045 
2046 /*
2047  * calculate a new RAD for this MST branch device
2048  * if parent has an LCT of 2 then it has 1 nibble of RAD,
2049  * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2050  */
drm_dp_calculate_rad(struct drm_dp_mst_port * port,u8 * rad)2051 static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2052 				 u8 *rad)
2053 {
2054 	int parent_lct = port->parent->lct;
2055 	int shift = 4;
2056 	int idx = (parent_lct - 1) / 2;
2057 
2058 	if (parent_lct > 1) {
2059 		memcpy(rad, port->parent->rad, idx + 1);
2060 		shift = (parent_lct % 2) ? 4 : 0;
2061 	} else
2062 		rad[0] = 0;
2063 
2064 	rad[idx] |= port->port_num << shift;
2065 	return parent_lct + 1;
2066 }
2067 
drm_dp_mst_is_end_device(u8 pdt,bool mcs)2068 static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2069 {
2070 	switch (pdt) {
2071 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
2072 	case DP_PEER_DEVICE_SST_SINK:
2073 		return true;
2074 	case DP_PEER_DEVICE_MST_BRANCHING:
2075 		/* For sst branch device */
2076 		if (!mcs)
2077 			return true;
2078 
2079 		return false;
2080 	}
2081 	return true;
2082 }
2083 
2084 static int
drm_dp_port_set_pdt(struct drm_dp_mst_port * port,u8 new_pdt,bool new_mcs)2085 drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2086 		    bool new_mcs)
2087 {
2088 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2089 	struct drm_dp_mst_branch *mstb;
2090 	u8 rad[8], lct;
2091 	int ret = 0;
2092 
2093 	if (port->pdt == new_pdt && port->mcs == new_mcs)
2094 		return 0;
2095 
2096 	/* Teardown the old pdt, if there is one */
2097 	if (port->pdt != DP_PEER_DEVICE_NONE) {
2098 		if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2099 			/*
2100 			 * If the new PDT would also have an i2c bus,
2101 			 * don't bother with reregistering it
2102 			 */
2103 			if (new_pdt != DP_PEER_DEVICE_NONE &&
2104 			    drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2105 				port->pdt = new_pdt;
2106 				port->mcs = new_mcs;
2107 				return 0;
2108 			}
2109 
2110 			/* remove i2c over sideband */
2111 			drm_dp_mst_unregister_i2c_bus(port);
2112 		} else {
2113 			mutex_lock(&mgr->lock);
2114 			drm_dp_mst_topology_put_mstb(port->mstb);
2115 			port->mstb = NULL;
2116 			mutex_unlock(&mgr->lock);
2117 		}
2118 	}
2119 
2120 	port->pdt = new_pdt;
2121 	port->mcs = new_mcs;
2122 
2123 	if (port->pdt != DP_PEER_DEVICE_NONE) {
2124 		if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2125 			/* add i2c over sideband */
2126 			ret = drm_dp_mst_register_i2c_bus(port);
2127 		} else {
2128 			lct = drm_dp_calculate_rad(port, rad);
2129 			mstb = drm_dp_add_mst_branch_device(lct, rad);
2130 			if (!mstb) {
2131 				ret = -ENOMEM;
2132 				DRM_ERROR("Failed to create MSTB for port %p",
2133 					  port);
2134 				goto out;
2135 			}
2136 
2137 			mutex_lock(&mgr->lock);
2138 			port->mstb = mstb;
2139 			mstb->mgr = port->mgr;
2140 			mstb->port_parent = port;
2141 
2142 			/*
2143 			 * Make sure this port's memory allocation stays
2144 			 * around until its child MSTB releases it
2145 			 */
2146 			drm_dp_mst_get_port_malloc(port);
2147 			mutex_unlock(&mgr->lock);
2148 
2149 			/* And make sure we send a link address for this */
2150 			ret = 1;
2151 		}
2152 	}
2153 
2154 out:
2155 	if (ret < 0)
2156 		port->pdt = DP_PEER_DEVICE_NONE;
2157 	return ret;
2158 }
2159 
2160 /**
2161  * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2162  * @aux: Fake sideband AUX CH
2163  * @offset: address of the (first) register to read
2164  * @buffer: buffer to store the register values
2165  * @size: number of bytes in @buffer
2166  *
2167  * Performs the same functionality for remote devices via
2168  * sideband messaging as drm_dp_dpcd_read() does for local
2169  * devices via actual AUX CH.
2170  *
2171  * Return: Number of bytes read, or negative error code on failure.
2172  */
drm_dp_mst_dpcd_read(struct drm_dp_aux * aux,unsigned int offset,void * buffer,size_t size)2173 ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2174 			     unsigned int offset, void *buffer, size_t size)
2175 {
2176 	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2177 						    aux);
2178 
2179 	return drm_dp_send_dpcd_read(port->mgr, port,
2180 				     offset, size, buffer);
2181 }
2182 
2183 /**
2184  * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2185  * @aux: Fake sideband AUX CH
2186  * @offset: address of the (first) register to write
2187  * @buffer: buffer containing the values to write
2188  * @size: number of bytes in @buffer
2189  *
2190  * Performs the same functionality for remote devices via
2191  * sideband messaging as drm_dp_dpcd_write() does for local
2192  * devices via actual AUX CH.
2193  *
2194  * Return: number of bytes written on success, negative error code on failure.
2195  */
drm_dp_mst_dpcd_write(struct drm_dp_aux * aux,unsigned int offset,void * buffer,size_t size)2196 ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2197 			      unsigned int offset, void *buffer, size_t size)
2198 {
2199 	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2200 						    aux);
2201 
2202 	return drm_dp_send_dpcd_write(port->mgr, port,
2203 				      offset, size, buffer);
2204 }
2205 
drm_dp_check_mstb_guid(struct drm_dp_mst_branch * mstb,u8 * guid)2206 static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2207 {
2208 	int ret = 0;
2209 
2210 	memcpy(mstb->guid, guid, 16);
2211 
2212 	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2213 		if (mstb->port_parent) {
2214 			ret = drm_dp_send_dpcd_write(mstb->mgr,
2215 						     mstb->port_parent,
2216 						     DP_GUID, 16, mstb->guid);
2217 		} else {
2218 			ret = drm_dp_dpcd_write(mstb->mgr->aux,
2219 						DP_GUID, mstb->guid, 16);
2220 		}
2221 	}
2222 
2223 	if (ret < 16 && ret > 0)
2224 		return -EPROTO;
2225 
2226 	return ret == 16 ? 0 : ret;
2227 }
2228 
build_mst_prop_path(const struct drm_dp_mst_branch * mstb,int pnum,char * proppath,size_t proppath_size)2229 static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2230 				int pnum,
2231 				char *proppath,
2232 				size_t proppath_size)
2233 {
2234 	int i;
2235 	char temp[8];
2236 
2237 	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2238 	for (i = 0; i < (mstb->lct - 1); i++) {
2239 		int shift = (i % 2) ? 0 : 4;
2240 		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2241 
2242 		snprintf(temp, sizeof(temp), "-%d", port_num);
2243 		strlcat(proppath, temp, proppath_size);
2244 	}
2245 	snprintf(temp, sizeof(temp), "-%d", pnum);
2246 	strlcat(proppath, temp, proppath_size);
2247 }
2248 
2249 /**
2250  * drm_dp_mst_connector_late_register() - Late MST connector registration
2251  * @connector: The MST connector
2252  * @port: The MST port for this connector
2253  *
2254  * Helper to register the remote aux device for this MST port. Drivers should
2255  * call this from their mst connector's late_register hook to enable MST aux
2256  * devices.
2257  *
2258  * Return: 0 on success, negative error code on failure.
2259  */
drm_dp_mst_connector_late_register(struct drm_connector * connector,struct drm_dp_mst_port * port)2260 int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2261 				       struct drm_dp_mst_port *port)
2262 {
2263 	DRM_DEBUG_KMS("registering %s remote bus for %s\n",
2264 		      port->aux.name, connector->kdev->kobj.name);
2265 
2266 	port->aux.dev = connector->kdev;
2267 	return drm_dp_aux_register_devnode(&port->aux);
2268 }
2269 EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2270 
2271 /**
2272  * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2273  * @connector: The MST connector
2274  * @port: The MST port for this connector
2275  *
2276  * Helper to unregister the remote aux device for this MST port, registered by
2277  * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2278  * connector's early_unregister hook.
2279  */
drm_dp_mst_connector_early_unregister(struct drm_connector * connector,struct drm_dp_mst_port * port)2280 void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2281 					   struct drm_dp_mst_port *port)
2282 {
2283 	DRM_DEBUG_KMS("unregistering %s remote bus for %s\n",
2284 		      port->aux.name, connector->kdev->kobj.name);
2285 	drm_dp_aux_unregister_devnode(&port->aux);
2286 }
2287 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2288 
2289 static void
drm_dp_mst_port_add_connector(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port)2290 drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2291 			      struct drm_dp_mst_port *port)
2292 {
2293 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2294 	char proppath[255];
2295 	int ret;
2296 
2297 	build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2298 	port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2299 	if (!port->connector) {
2300 		ret = -ENOMEM;
2301 		goto error;
2302 	}
2303 
2304 	if (port->pdt != DP_PEER_DEVICE_NONE &&
2305 	    drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2306 		port->cached_edid = drm_get_edid(port->connector,
2307 						 &port->aux.ddc);
2308 		drm_connector_set_tile_property(port->connector);
2309 	}
2310 
2311 	drm_connector_register(port->connector);
2312 	return;
2313 
2314 error:
2315 	DRM_ERROR("Failed to create connector for port %p: %d\n", port, ret);
2316 }
2317 
2318 /*
2319  * Drop a topology reference, and unlink the port from the in-memory topology
2320  * layout
2321  */
2322 static void
drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)2323 drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2324 				struct drm_dp_mst_port *port)
2325 {
2326 	mutex_lock(&mgr->lock);
2327 	port->parent->num_ports--;
2328 	list_del(&port->next);
2329 	mutex_unlock(&mgr->lock);
2330 	drm_dp_mst_topology_put_port(port);
2331 }
2332 
2333 static struct drm_dp_mst_port *
drm_dp_mst_add_port(struct drm_device * dev,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,u8 port_number)2334 drm_dp_mst_add_port(struct drm_device *dev,
2335 		    struct drm_dp_mst_topology_mgr *mgr,
2336 		    struct drm_dp_mst_branch *mstb, u8 port_number)
2337 {
2338 	struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2339 
2340 	if (!port)
2341 		return NULL;
2342 
2343 	kref_init(&port->topology_kref);
2344 	kref_init(&port->malloc_kref);
2345 	port->parent = mstb;
2346 	port->port_num = port_number;
2347 	port->mgr = mgr;
2348 	port->aux.name = "DPMST";
2349 	port->aux.dev = dev->dev;
2350 	port->aux.is_remote = true;
2351 
2352 	/* initialize the MST downstream port's AUX crc work queue */
2353 	drm_dp_remote_aux_init(&port->aux);
2354 
2355 	/*
2356 	 * Make sure the memory allocation for our parent branch stays
2357 	 * around until our own memory allocation is released
2358 	 */
2359 	drm_dp_mst_get_mstb_malloc(mstb);
2360 
2361 	return port;
2362 }
2363 
2364 static int
drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch * mstb,struct drm_device * dev,struct drm_dp_link_addr_reply_port * port_msg)2365 drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2366 				    struct drm_device *dev,
2367 				    struct drm_dp_link_addr_reply_port *port_msg)
2368 {
2369 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2370 	struct drm_dp_mst_port *port;
2371 	int old_ddps = 0, ret;
2372 	u8 new_pdt = DP_PEER_DEVICE_NONE;
2373 	bool new_mcs = 0;
2374 	bool created = false, send_link_addr = false, changed = false;
2375 
2376 	port = drm_dp_get_port(mstb, port_msg->port_number);
2377 	if (!port) {
2378 		port = drm_dp_mst_add_port(dev, mgr, mstb,
2379 					   port_msg->port_number);
2380 		if (!port)
2381 			return -ENOMEM;
2382 		created = true;
2383 		changed = true;
2384 	} else if (!port->input && port_msg->input_port && port->connector) {
2385 		/* Since port->connector can't be changed here, we create a
2386 		 * new port if input_port changes from 0 to 1
2387 		 */
2388 		drm_dp_mst_topology_unlink_port(mgr, port);
2389 		drm_dp_mst_topology_put_port(port);
2390 		port = drm_dp_mst_add_port(dev, mgr, mstb,
2391 					   port_msg->port_number);
2392 		if (!port)
2393 			return -ENOMEM;
2394 		changed = true;
2395 		created = true;
2396 	} else if (port->input && !port_msg->input_port) {
2397 		changed = true;
2398 	} else if (port->connector) {
2399 		/* We're updating a port that's exposed to userspace, so do it
2400 		 * under lock
2401 		 */
2402 		drm_modeset_lock(&mgr->base.lock, NULL);
2403 
2404 		old_ddps = port->ddps;
2405 		changed = port->ddps != port_msg->ddps ||
2406 			(port->ddps &&
2407 			 (port->ldps != port_msg->legacy_device_plug_status ||
2408 			  port->dpcd_rev != port_msg->dpcd_revision ||
2409 			  port->mcs != port_msg->mcs ||
2410 			  port->pdt != port_msg->peer_device_type ||
2411 			  port->num_sdp_stream_sinks !=
2412 			  port_msg->num_sdp_stream_sinks));
2413 	}
2414 
2415 	port->input = port_msg->input_port;
2416 	if (!port->input)
2417 		new_pdt = port_msg->peer_device_type;
2418 	new_mcs = port_msg->mcs;
2419 	port->ddps = port_msg->ddps;
2420 	port->ldps = port_msg->legacy_device_plug_status;
2421 	port->dpcd_rev = port_msg->dpcd_revision;
2422 	port->num_sdp_streams = port_msg->num_sdp_streams;
2423 	port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2424 
2425 	/* manage mstb port lists with mgr lock - take a reference
2426 	   for this list */
2427 	if (created) {
2428 		mutex_lock(&mgr->lock);
2429 		drm_dp_mst_topology_get_port(port);
2430 		list_add(&port->next, &mstb->ports);
2431 		mstb->num_ports++;
2432 		mutex_unlock(&mgr->lock);
2433 	}
2434 
2435 	/*
2436 	 * Reprobe PBN caps on both hotplug, and when re-probing the link
2437 	 * for our parent mstb
2438 	 */
2439 	if (old_ddps != port->ddps || !created) {
2440 		if (port->ddps && !port->input) {
2441 			ret = drm_dp_send_enum_path_resources(mgr, mstb,
2442 							      port);
2443 			if (ret == 1)
2444 				changed = true;
2445 		} else {
2446 			port->full_pbn = 0;
2447 		}
2448 	}
2449 
2450 	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2451 	if (ret == 1) {
2452 		send_link_addr = true;
2453 	} else if (ret < 0) {
2454 		DRM_ERROR("Failed to change PDT on port %p: %d\n",
2455 			  port, ret);
2456 		goto fail;
2457 	}
2458 
2459 	/*
2460 	 * If this port wasn't just created, then we're reprobing because
2461 	 * we're coming out of suspend. In this case, always resend the link
2462 	 * address if there's an MSTB on this port
2463 	 */
2464 	if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2465 	    port->mcs)
2466 		send_link_addr = true;
2467 
2468 	if (port->connector)
2469 		drm_modeset_unlock(&mgr->base.lock);
2470 	else if (!port->input)
2471 		drm_dp_mst_port_add_connector(mstb, port);
2472 
2473 	if (send_link_addr && port->mstb) {
2474 		ret = drm_dp_send_link_address(mgr, port->mstb);
2475 		if (ret == 1) /* MSTB below us changed */
2476 			changed = true;
2477 		else if (ret < 0)
2478 			goto fail_put;
2479 	}
2480 
2481 	/* put reference to this port */
2482 	drm_dp_mst_topology_put_port(port);
2483 	return changed;
2484 
2485 fail:
2486 	drm_dp_mst_topology_unlink_port(mgr, port);
2487 	if (port->connector)
2488 		drm_modeset_unlock(&mgr->base.lock);
2489 fail_put:
2490 	drm_dp_mst_topology_put_port(port);
2491 	return ret;
2492 }
2493 
2494 static void
drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch * mstb,struct drm_dp_connection_status_notify * conn_stat)2495 drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2496 			    struct drm_dp_connection_status_notify *conn_stat)
2497 {
2498 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2499 	struct drm_dp_mst_port *port;
2500 	int old_ddps, old_input, ret, i;
2501 	u8 new_pdt;
2502 	bool new_mcs;
2503 	bool dowork = false, create_connector = false;
2504 
2505 	port = drm_dp_get_port(mstb, conn_stat->port_number);
2506 	if (!port)
2507 		return;
2508 
2509 	if (port->connector) {
2510 		if (!port->input && conn_stat->input_port) {
2511 			/*
2512 			 * We can't remove a connector from an already exposed
2513 			 * port, so just throw the port out and make sure we
2514 			 * reprobe the link address of it's parent MSTB
2515 			 */
2516 			drm_dp_mst_topology_unlink_port(mgr, port);
2517 			mstb->link_address_sent = false;
2518 			dowork = true;
2519 			goto out;
2520 		}
2521 
2522 		/* Locking is only needed if the port's exposed to userspace */
2523 		drm_modeset_lock(&mgr->base.lock, NULL);
2524 	} else if (port->input && !conn_stat->input_port) {
2525 		create_connector = true;
2526 		/* Reprobe link address so we get num_sdp_streams */
2527 		mstb->link_address_sent = false;
2528 		dowork = true;
2529 	}
2530 
2531 	old_ddps = port->ddps;
2532 	old_input = port->input;
2533 	port->input = conn_stat->input_port;
2534 	port->ldps = conn_stat->legacy_device_plug_status;
2535 	port->ddps = conn_stat->displayport_device_plug_status;
2536 
2537 	if (old_ddps != port->ddps) {
2538 		if (port->ddps && !port->input)
2539 			drm_dp_send_enum_path_resources(mgr, mstb, port);
2540 		else
2541 			port->full_pbn = 0;
2542 	}
2543 
2544 	new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2545 	new_mcs = conn_stat->message_capability_status;
2546 	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2547 	if (ret == 1) {
2548 		dowork = true;
2549 	} else if (ret < 0) {
2550 		DRM_ERROR("Failed to change PDT for port %p: %d\n",
2551 			  port, ret);
2552 		dowork = false;
2553 	}
2554 
2555 	if (!old_input && old_ddps != port->ddps && !port->ddps) {
2556 		for (i = 0; i < mgr->max_payloads; i++) {
2557 			struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
2558 			struct drm_dp_mst_port *port_validated;
2559 
2560 			if (!vcpi)
2561 				continue;
2562 
2563 			port_validated =
2564 				container_of(vcpi, struct drm_dp_mst_port, vcpi);
2565 			port_validated =
2566 				drm_dp_mst_topology_get_port_validated(mgr, port_validated);
2567 			if (!port_validated) {
2568 				mutex_lock(&mgr->payload_lock);
2569 				vcpi->num_slots = 0;
2570 				mutex_unlock(&mgr->payload_lock);
2571 			} else {
2572 				drm_dp_mst_topology_put_port(port_validated);
2573 			}
2574 		}
2575 	}
2576 
2577 	if (port->connector)
2578 		drm_modeset_unlock(&mgr->base.lock);
2579 	else if (create_connector)
2580 		drm_dp_mst_port_add_connector(mstb, port);
2581 
2582 out:
2583 	drm_dp_mst_topology_put_port(port);
2584 	if (dowork)
2585 		queue_work(system_long_wq, &mstb->mgr->work);
2586 }
2587 
drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr * mgr,u8 lct,u8 * rad)2588 static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2589 							       u8 lct, u8 *rad)
2590 {
2591 	struct drm_dp_mst_branch *mstb;
2592 	struct drm_dp_mst_port *port;
2593 	int i, ret;
2594 	/* find the port by iterating down */
2595 
2596 	mutex_lock(&mgr->lock);
2597 	mstb = mgr->mst_primary;
2598 
2599 	if (!mstb)
2600 		goto out;
2601 
2602 	for (i = 0; i < lct - 1; i++) {
2603 		int shift = (i % 2) ? 0 : 4;
2604 		int port_num = (rad[i / 2] >> shift) & 0xf;
2605 
2606 		list_for_each_entry(port, &mstb->ports, next) {
2607 			if (port->port_num == port_num) {
2608 				mstb = port->mstb;
2609 				if (!mstb) {
2610 					DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
2611 					goto out;
2612 				}
2613 
2614 				break;
2615 			}
2616 		}
2617 	}
2618 	ret = drm_dp_mst_topology_try_get_mstb(mstb);
2619 	if (!ret)
2620 		mstb = NULL;
2621 out:
2622 	mutex_unlock(&mgr->lock);
2623 	return mstb;
2624 }
2625 
get_mst_branch_device_by_guid_helper(struct drm_dp_mst_branch * mstb,const uint8_t * guid)2626 static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2627 	struct drm_dp_mst_branch *mstb,
2628 	const uint8_t *guid)
2629 {
2630 	struct drm_dp_mst_branch *found_mstb;
2631 	struct drm_dp_mst_port *port;
2632 
2633 	if (memcmp(mstb->guid, guid, 16) == 0)
2634 		return mstb;
2635 
2636 
2637 	list_for_each_entry(port, &mstb->ports, next) {
2638 		if (!port->mstb)
2639 			continue;
2640 
2641 		found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2642 
2643 		if (found_mstb)
2644 			return found_mstb;
2645 	}
2646 
2647 	return NULL;
2648 }
2649 
2650 static struct drm_dp_mst_branch *
drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr * mgr,const uint8_t * guid)2651 drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2652 				     const uint8_t *guid)
2653 {
2654 	struct drm_dp_mst_branch *mstb;
2655 	int ret;
2656 
2657 	/* find the port by iterating down */
2658 	mutex_lock(&mgr->lock);
2659 
2660 	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2661 	if (mstb) {
2662 		ret = drm_dp_mst_topology_try_get_mstb(mstb);
2663 		if (!ret)
2664 			mstb = NULL;
2665 	}
2666 
2667 	mutex_unlock(&mgr->lock);
2668 	return mstb;
2669 }
2670 
drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)2671 static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2672 					       struct drm_dp_mst_branch *mstb)
2673 {
2674 	struct drm_dp_mst_port *port;
2675 	int ret;
2676 	bool changed = false;
2677 
2678 	if (!mstb->link_address_sent) {
2679 		ret = drm_dp_send_link_address(mgr, mstb);
2680 		if (ret == 1)
2681 			changed = true;
2682 		else if (ret < 0)
2683 			return ret;
2684 	}
2685 
2686 	list_for_each_entry(port, &mstb->ports, next) {
2687 		struct drm_dp_mst_branch *mstb_child = NULL;
2688 
2689 		if (port->input || !port->ddps)
2690 			continue;
2691 
2692 		if (port->mstb)
2693 			mstb_child = drm_dp_mst_topology_get_mstb_validated(
2694 			    mgr, port->mstb);
2695 
2696 		if (mstb_child) {
2697 			ret = drm_dp_check_and_send_link_address(mgr,
2698 								 mstb_child);
2699 			drm_dp_mst_topology_put_mstb(mstb_child);
2700 			if (ret == 1)
2701 				changed = true;
2702 			else if (ret < 0)
2703 				return ret;
2704 		}
2705 	}
2706 
2707 	return changed;
2708 }
2709 
drm_dp_mst_link_probe_work(struct work_struct * work)2710 static void drm_dp_mst_link_probe_work(struct work_struct *work)
2711 {
2712 	struct drm_dp_mst_topology_mgr *mgr =
2713 		container_of(work, struct drm_dp_mst_topology_mgr, work);
2714 	struct drm_device *dev = mgr->dev;
2715 	struct drm_dp_mst_branch *mstb;
2716 	int ret;
2717 	bool clear_payload_id_table;
2718 
2719 	mutex_lock(&mgr->probe_lock);
2720 
2721 	mutex_lock(&mgr->lock);
2722 	clear_payload_id_table = !mgr->payload_id_table_cleared;
2723 	mgr->payload_id_table_cleared = true;
2724 
2725 	mstb = mgr->mst_primary;
2726 	if (mstb) {
2727 		ret = drm_dp_mst_topology_try_get_mstb(mstb);
2728 		if (!ret)
2729 			mstb = NULL;
2730 	}
2731 	mutex_unlock(&mgr->lock);
2732 	if (!mstb) {
2733 		mutex_unlock(&mgr->probe_lock);
2734 		return;
2735 	}
2736 
2737 	/*
2738 	 * Certain branch devices seem to incorrectly report an available_pbn
2739 	 * of 0 on downstream sinks, even after clearing the
2740 	 * DP_PAYLOAD_ALLOCATE_* registers in
2741 	 * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2742 	 * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2743 	 * things work again.
2744 	 */
2745 	if (clear_payload_id_table) {
2746 		DRM_DEBUG_KMS("Clearing payload ID table\n");
2747 		drm_dp_send_clear_payload_id_table(mgr, mstb);
2748 	}
2749 
2750 	ret = drm_dp_check_and_send_link_address(mgr, mstb);
2751 	drm_dp_mst_topology_put_mstb(mstb);
2752 
2753 	mutex_unlock(&mgr->probe_lock);
2754 	if (ret)
2755 		drm_kms_helper_hotplug_event(dev);
2756 }
2757 
drm_dp_validate_guid(struct drm_dp_mst_topology_mgr * mgr,u8 * guid)2758 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2759 				 u8 *guid)
2760 {
2761 	u64 salt;
2762 
2763 	if (memchr_inv(guid, 0, 16))
2764 		return true;
2765 
2766 	salt = get_jiffies_64();
2767 
2768 	memcpy(&guid[0], &salt, sizeof(u64));
2769 	memcpy(&guid[8], &salt, sizeof(u64));
2770 
2771 	return false;
2772 }
2773 
build_dpcd_read(struct drm_dp_sideband_msg_tx * msg,u8 port_num,u32 offset,u8 num_bytes)2774 static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2775 			    u8 port_num, u32 offset, u8 num_bytes)
2776 {
2777 	struct drm_dp_sideband_msg_req_body req;
2778 
2779 	req.req_type = DP_REMOTE_DPCD_READ;
2780 	req.u.dpcd_read.port_number = port_num;
2781 	req.u.dpcd_read.dpcd_address = offset;
2782 	req.u.dpcd_read.num_bytes = num_bytes;
2783 	drm_dp_encode_sideband_req(&req, msg);
2784 }
2785 
drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr * mgr,bool up,u8 * msg,int len)2786 static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2787 				    bool up, u8 *msg, int len)
2788 {
2789 	int ret;
2790 	int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2791 	int tosend, total, offset;
2792 	int retries = 0;
2793 
2794 retry:
2795 	total = len;
2796 	offset = 0;
2797 	do {
2798 		tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2799 
2800 		ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2801 					&msg[offset],
2802 					tosend);
2803 		if (ret != tosend) {
2804 			if (ret == -EIO && retries < 5) {
2805 				retries++;
2806 				goto retry;
2807 			}
2808 			DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
2809 
2810 			return -EIO;
2811 		}
2812 		offset += tosend;
2813 		total -= tosend;
2814 	} while (total > 0);
2815 	return 0;
2816 }
2817 
set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr * hdr,struct drm_dp_sideband_msg_tx * txmsg)2818 static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2819 				  struct drm_dp_sideband_msg_tx *txmsg)
2820 {
2821 	struct drm_dp_mst_branch *mstb = txmsg->dst;
2822 	u8 req_type;
2823 
2824 	req_type = txmsg->msg[0] & 0x7f;
2825 	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2826 		req_type == DP_RESOURCE_STATUS_NOTIFY)
2827 		hdr->broadcast = 1;
2828 	else
2829 		hdr->broadcast = 0;
2830 	hdr->path_msg = txmsg->path_msg;
2831 	hdr->lct = mstb->lct;
2832 	hdr->lcr = mstb->lct - 1;
2833 	if (mstb->lct > 1)
2834 		memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
2835 
2836 	return 0;
2837 }
2838 /*
2839  * process a single block of the next message in the sideband queue
2840  */
process_single_tx_qlock(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_tx * txmsg,bool up)2841 static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2842 				   struct drm_dp_sideband_msg_tx *txmsg,
2843 				   bool up)
2844 {
2845 	u8 chunk[48];
2846 	struct drm_dp_sideband_msg_hdr hdr;
2847 	int len, space, idx, tosend;
2848 	int ret;
2849 
2850 	if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2851 		return 0;
2852 
2853 	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2854 
2855 	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2856 		txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2857 
2858 	/* make hdr from dst mst */
2859 	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2860 	if (ret < 0)
2861 		return ret;
2862 
2863 	/* amount left to send in this message */
2864 	len = txmsg->cur_len - txmsg->cur_offset;
2865 
2866 	/* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2867 	space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2868 
2869 	tosend = min(len, space);
2870 	if (len == txmsg->cur_len)
2871 		hdr.somt = 1;
2872 	if (space >= len)
2873 		hdr.eomt = 1;
2874 
2875 
2876 	hdr.msg_len = tosend + 1;
2877 	drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2878 	memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2879 	/* add crc at end */
2880 	drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2881 	idx += tosend + 1;
2882 
2883 	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2884 	if (unlikely(ret) && drm_debug_enabled(DRM_UT_DP)) {
2885 		struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2886 
2887 		drm_printf(&p, "sideband msg failed to send\n");
2888 		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2889 		return ret;
2890 	}
2891 
2892 	txmsg->cur_offset += tosend;
2893 	if (txmsg->cur_offset == txmsg->cur_len) {
2894 		txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2895 		return 1;
2896 	}
2897 	return 0;
2898 }
2899 
process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr * mgr)2900 static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2901 {
2902 	struct drm_dp_sideband_msg_tx *txmsg;
2903 	int ret;
2904 
2905 	WARN_ON(!mutex_is_locked(&mgr->qlock));
2906 
2907 	/* construct a chunk from the first msg in the tx_msg queue */
2908 	if (list_empty(&mgr->tx_msg_downq))
2909 		return;
2910 
2911 	txmsg = list_first_entry(&mgr->tx_msg_downq,
2912 				 struct drm_dp_sideband_msg_tx, next);
2913 	ret = process_single_tx_qlock(mgr, txmsg, false);
2914 	if (ret < 0) {
2915 		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
2916 		list_del(&txmsg->next);
2917 		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2918 		wake_up_all(&mgr->tx_waitq);
2919 	}
2920 }
2921 
drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_sideband_msg_tx * txmsg)2922 static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2923 				 struct drm_dp_sideband_msg_tx *txmsg)
2924 {
2925 	mutex_lock(&mgr->qlock);
2926 	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2927 
2928 	if (drm_debug_enabled(DRM_UT_DP)) {
2929 		struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2930 
2931 		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2932 	}
2933 
2934 	if (list_is_singular(&mgr->tx_msg_downq))
2935 		process_single_down_tx_qlock(mgr);
2936 	mutex_unlock(&mgr->qlock);
2937 }
2938 
2939 static void
drm_dp_dump_link_address(struct drm_dp_link_address_ack_reply * reply)2940 drm_dp_dump_link_address(struct drm_dp_link_address_ack_reply *reply)
2941 {
2942 	struct drm_dp_link_addr_reply_port *port_reply;
2943 	int i;
2944 
2945 	for (i = 0; i < reply->nports; i++) {
2946 		port_reply = &reply->ports[i];
2947 		DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2948 			      i,
2949 			      port_reply->input_port,
2950 			      port_reply->peer_device_type,
2951 			      port_reply->port_number,
2952 			      port_reply->dpcd_revision,
2953 			      port_reply->mcs,
2954 			      port_reply->ddps,
2955 			      port_reply->legacy_device_plug_status,
2956 			      port_reply->num_sdp_streams,
2957 			      port_reply->num_sdp_stream_sinks);
2958 	}
2959 }
2960 
drm_dp_send_link_address(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)2961 static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2962 				     struct drm_dp_mst_branch *mstb)
2963 {
2964 	struct drm_dp_sideband_msg_tx *txmsg;
2965 	struct drm_dp_link_address_ack_reply *reply;
2966 	struct drm_dp_mst_port *port, *tmp;
2967 	int i, ret, port_mask = 0;
2968 	bool changed = false;
2969 
2970 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2971 	if (!txmsg)
2972 		return -ENOMEM;
2973 
2974 	txmsg->dst = mstb;
2975 	build_link_address(txmsg);
2976 
2977 	mstb->link_address_sent = true;
2978 	drm_dp_queue_down_tx(mgr, txmsg);
2979 
2980 	/* FIXME: Actually do some real error handling here */
2981 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2982 	if (ret <= 0) {
2983 		DRM_ERROR("Sending link address failed with %d\n", ret);
2984 		goto out;
2985 	}
2986 	if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2987 		DRM_ERROR("link address NAK received\n");
2988 		ret = -EIO;
2989 		goto out;
2990 	}
2991 
2992 	reply = &txmsg->reply.u.link_addr;
2993 	DRM_DEBUG_KMS("link address reply: %d\n", reply->nports);
2994 	drm_dp_dump_link_address(reply);
2995 
2996 	ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2997 	if (ret) {
2998 		char buf[64];
2999 
3000 		drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
3001 		DRM_ERROR("GUID check on %s failed: %d\n",
3002 			  buf, ret);
3003 		goto out;
3004 	}
3005 
3006 	for (i = 0; i < reply->nports; i++) {
3007 		port_mask |= BIT(reply->ports[i].port_number);
3008 		ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
3009 							  &reply->ports[i]);
3010 		if (ret == 1)
3011 			changed = true;
3012 		else if (ret < 0)
3013 			goto out;
3014 	}
3015 
3016 	/* Prune any ports that are currently a part of mstb in our in-memory
3017 	 * topology, but were not seen in this link address. Usually this
3018 	 * means that they were removed while the topology was out of sync,
3019 	 * e.g. during suspend/resume
3020 	 */
3021 	mutex_lock(&mgr->lock);
3022 	list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
3023 		if (port_mask & BIT(port->port_num))
3024 			continue;
3025 
3026 		DRM_DEBUG_KMS("port %d was not in link address, removing\n",
3027 			      port->port_num);
3028 		list_del(&port->next);
3029 		drm_dp_mst_topology_put_port(port);
3030 		changed = true;
3031 	}
3032 	mutex_unlock(&mgr->lock);
3033 
3034 out:
3035 	if (ret <= 0)
3036 		mstb->link_address_sent = false;
3037 	kfree(txmsg);
3038 	return ret < 0 ? ret : changed;
3039 }
3040 
3041 static void
drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb)3042 drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
3043 				   struct drm_dp_mst_branch *mstb)
3044 {
3045 	struct drm_dp_sideband_msg_tx *txmsg;
3046 	int ret;
3047 
3048 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3049 	if (!txmsg)
3050 		return;
3051 
3052 	txmsg->dst = mstb;
3053 	build_clear_payload_id_table(txmsg);
3054 
3055 	drm_dp_queue_down_tx(mgr, txmsg);
3056 
3057 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3058 	if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3059 		DRM_DEBUG_KMS("clear payload table id nak received\n");
3060 
3061 	kfree(txmsg);
3062 }
3063 
3064 static int
drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port)3065 drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3066 				struct drm_dp_mst_branch *mstb,
3067 				struct drm_dp_mst_port *port)
3068 {
3069 	struct drm_dp_enum_path_resources_ack_reply *path_res;
3070 	struct drm_dp_sideband_msg_tx *txmsg;
3071 	int ret;
3072 
3073 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3074 	if (!txmsg)
3075 		return -ENOMEM;
3076 
3077 	txmsg->dst = mstb;
3078 	build_enum_path_resources(txmsg, port->port_num);
3079 
3080 	drm_dp_queue_down_tx(mgr, txmsg);
3081 
3082 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3083 	if (ret > 0) {
3084 		ret = 0;
3085 		path_res = &txmsg->reply.u.path_resources;
3086 
3087 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3088 			DRM_DEBUG_KMS("enum path resources nak received\n");
3089 		} else {
3090 			if (port->port_num != path_res->port_number)
3091 				DRM_ERROR("got incorrect port in response\n");
3092 
3093 			DRM_DEBUG_KMS("enum path resources %d: %d %d\n",
3094 				      path_res->port_number,
3095 				      path_res->full_payload_bw_number,
3096 				      path_res->avail_payload_bw_number);
3097 
3098 			/*
3099 			 * If something changed, make sure we send a
3100 			 * hotplug
3101 			 */
3102 			if (port->full_pbn != path_res->full_payload_bw_number ||
3103 			    port->fec_capable != path_res->fec_capable)
3104 				ret = 1;
3105 
3106 			port->full_pbn = path_res->full_payload_bw_number;
3107 			port->fec_capable = path_res->fec_capable;
3108 		}
3109 	}
3110 
3111 	kfree(txmsg);
3112 	return ret;
3113 }
3114 
drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch * mstb)3115 static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3116 {
3117 	if (!mstb->port_parent)
3118 		return NULL;
3119 
3120 	if (mstb->port_parent->mstb != mstb)
3121 		return mstb->port_parent;
3122 
3123 	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3124 }
3125 
3126 /*
3127  * Searches upwards in the topology starting from mstb to try to find the
3128  * closest available parent of mstb that's still connected to the rest of the
3129  * topology. This can be used in order to perform operations like releasing
3130  * payloads, where the branch device which owned the payload may no longer be
3131  * around and thus would require that the payload on the last living relative
3132  * be freed instead.
3133  */
3134 static struct drm_dp_mst_branch *
drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,int * port_num)3135 drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3136 					struct drm_dp_mst_branch *mstb,
3137 					int *port_num)
3138 {
3139 	struct drm_dp_mst_branch *rmstb = NULL;
3140 	struct drm_dp_mst_port *found_port;
3141 
3142 	mutex_lock(&mgr->lock);
3143 	if (!mgr->mst_primary)
3144 		goto out;
3145 
3146 	do {
3147 		found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3148 		if (!found_port)
3149 			break;
3150 
3151 		if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3152 			rmstb = found_port->parent;
3153 			*port_num = found_port->port_num;
3154 		} else {
3155 			/* Search again, starting from this parent */
3156 			mstb = found_port->parent;
3157 		}
3158 	} while (!rmstb);
3159 out:
3160 	mutex_unlock(&mgr->lock);
3161 	return rmstb;
3162 }
3163 
drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int id,int pbn)3164 static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3165 				   struct drm_dp_mst_port *port,
3166 				   int id,
3167 				   int pbn)
3168 {
3169 	struct drm_dp_sideband_msg_tx *txmsg;
3170 	struct drm_dp_mst_branch *mstb;
3171 	int ret, port_num;
3172 	u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3173 	int i;
3174 
3175 	port_num = port->port_num;
3176 	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3177 	if (!mstb) {
3178 		mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3179 							       port->parent,
3180 							       &port_num);
3181 
3182 		if (!mstb)
3183 			return -EINVAL;
3184 	}
3185 
3186 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3187 	if (!txmsg) {
3188 		ret = -ENOMEM;
3189 		goto fail_put;
3190 	}
3191 
3192 	for (i = 0; i < port->num_sdp_streams; i++)
3193 		sinks[i] = i;
3194 
3195 	txmsg->dst = mstb;
3196 	build_allocate_payload(txmsg, port_num,
3197 			       id,
3198 			       pbn, port->num_sdp_streams, sinks);
3199 
3200 	drm_dp_queue_down_tx(mgr, txmsg);
3201 
3202 	/*
3203 	 * FIXME: there is a small chance that between getting the last
3204 	 * connected mstb and sending the payload message, the last connected
3205 	 * mstb could also be removed from the topology. In the future, this
3206 	 * needs to be fixed by restarting the
3207 	 * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3208 	 * timeout if the topology is still connected to the system.
3209 	 */
3210 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3211 	if (ret > 0) {
3212 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3213 			ret = -EINVAL;
3214 		else
3215 			ret = 0;
3216 	}
3217 	kfree(txmsg);
3218 fail_put:
3219 	drm_dp_mst_topology_put_mstb(mstb);
3220 	return ret;
3221 }
3222 
drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,bool power_up)3223 int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3224 				 struct drm_dp_mst_port *port, bool power_up)
3225 {
3226 	struct drm_dp_sideband_msg_tx *txmsg;
3227 	int ret;
3228 
3229 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3230 	if (!port)
3231 		return -EINVAL;
3232 
3233 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3234 	if (!txmsg) {
3235 		drm_dp_mst_topology_put_port(port);
3236 		return -ENOMEM;
3237 	}
3238 
3239 	txmsg->dst = port->parent;
3240 	build_power_updown_phy(txmsg, port->port_num, power_up);
3241 	drm_dp_queue_down_tx(mgr, txmsg);
3242 
3243 	ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3244 	if (ret > 0) {
3245 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3246 			ret = -EINVAL;
3247 		else
3248 			ret = 0;
3249 	}
3250 	kfree(txmsg);
3251 	drm_dp_mst_topology_put_port(port);
3252 
3253 	return ret;
3254 }
3255 EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3256 
drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,struct drm_dp_query_stream_enc_status_ack_reply * status)3257 int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3258 		struct drm_dp_mst_port *port,
3259 		struct drm_dp_query_stream_enc_status_ack_reply *status)
3260 {
3261 	struct drm_dp_sideband_msg_tx *txmsg;
3262 	u8 nonce[7];
3263 	int len, ret;
3264 
3265 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3266 	if (!txmsg)
3267 		return -ENOMEM;
3268 
3269 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3270 	if (!port) {
3271 		ret = -EINVAL;
3272 		goto out_get_port;
3273 	}
3274 
3275 	get_random_bytes(nonce, sizeof(nonce));
3276 
3277 	/*
3278 	 * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3279 	 *  transaction at the MST Branch device directly connected to the
3280 	 *  Source"
3281 	 */
3282 	txmsg->dst = mgr->mst_primary;
3283 
3284 	len = build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
3285 
3286 	drm_dp_queue_down_tx(mgr, txmsg);
3287 
3288 	ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3289 	if (ret < 0) {
3290 		goto out;
3291 	} else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3292 		drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3293 		ret = -ENXIO;
3294 		goto out;
3295 	}
3296 
3297 	ret = 0;
3298 	memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3299 
3300 out:
3301 	drm_dp_mst_topology_put_port(port);
3302 out_get_port:
3303 	kfree(txmsg);
3304 	return ret;
3305 }
3306 EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3307 
drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr * mgr,int id,struct drm_dp_payload * payload)3308 static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3309 				       int id,
3310 				       struct drm_dp_payload *payload)
3311 {
3312 	int ret;
3313 
3314 	ret = drm_dp_dpcd_write_payload(mgr, id, payload);
3315 	if (ret < 0) {
3316 		payload->payload_state = 0;
3317 		return ret;
3318 	}
3319 	payload->payload_state = DP_PAYLOAD_LOCAL;
3320 	return 0;
3321 }
3322 
drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int id,struct drm_dp_payload * payload)3323 static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3324 				       struct drm_dp_mst_port *port,
3325 				       int id,
3326 				       struct drm_dp_payload *payload)
3327 {
3328 	int ret;
3329 
3330 	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
3331 	if (ret < 0)
3332 		return ret;
3333 	payload->payload_state = DP_PAYLOAD_REMOTE;
3334 	return ret;
3335 }
3336 
drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int id,struct drm_dp_payload * payload)3337 static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3338 					struct drm_dp_mst_port *port,
3339 					int id,
3340 					struct drm_dp_payload *payload)
3341 {
3342 	DRM_DEBUG_KMS("\n");
3343 	/* it's okay for these to fail */
3344 	if (port) {
3345 		drm_dp_payload_send_msg(mgr, port, id, 0);
3346 	}
3347 
3348 	drm_dp_dpcd_write_payload(mgr, id, payload);
3349 	payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
3350 	return 0;
3351 }
3352 
drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr * mgr,int id,struct drm_dp_payload * payload)3353 static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3354 					int id,
3355 					struct drm_dp_payload *payload)
3356 {
3357 	payload->payload_state = 0;
3358 	return 0;
3359 }
3360 
3361 /**
3362  * drm_dp_update_payload_part1() - Execute payload update part 1
3363  * @mgr: manager to use.
3364  *
3365  * This iterates over all proposed virtual channels, and tries to
3366  * allocate space in the link for them. For 0->slots transitions,
3367  * this step just writes the VCPI to the MST device. For slots->0
3368  * transitions, this writes the updated VCPIs and removes the
3369  * remote VC payloads.
3370  *
3371  * after calling this the driver should generate ACT and payload
3372  * packets.
3373  */
drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr * mgr)3374 int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
3375 {
3376 	struct drm_dp_payload req_payload;
3377 	struct drm_dp_mst_port *port;
3378 	int i, j;
3379 	int cur_slots = 1;
3380 
3381 	mutex_lock(&mgr->payload_lock);
3382 	for (i = 0; i < mgr->max_payloads; i++) {
3383 		struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
3384 		struct drm_dp_payload *payload = &mgr->payloads[i];
3385 		bool put_port = false;
3386 
3387 		/* solve the current payloads - compare to the hw ones
3388 		   - update the hw view */
3389 		req_payload.start_slot = cur_slots;
3390 		if (vcpi) {
3391 			port = container_of(vcpi, struct drm_dp_mst_port,
3392 					    vcpi);
3393 
3394 			/* Validated ports don't matter if we're releasing
3395 			 * VCPI
3396 			 */
3397 			if (vcpi->num_slots) {
3398 				port = drm_dp_mst_topology_get_port_validated(
3399 				    mgr, port);
3400 				if (!port) {
3401 					mutex_unlock(&mgr->payload_lock);
3402 					return -EINVAL;
3403 				}
3404 				put_port = true;
3405 			}
3406 
3407 			req_payload.num_slots = vcpi->num_slots;
3408 			req_payload.vcpi = vcpi->vcpi;
3409 		} else {
3410 			port = NULL;
3411 			req_payload.num_slots = 0;
3412 		}
3413 
3414 		payload->start_slot = req_payload.start_slot;
3415 		/* work out what is required to happen with this payload */
3416 		if (payload->num_slots != req_payload.num_slots) {
3417 
3418 			/* need to push an update for this payload */
3419 			if (req_payload.num_slots) {
3420 				drm_dp_create_payload_step1(mgr, vcpi->vcpi,
3421 							    &req_payload);
3422 				payload->num_slots = req_payload.num_slots;
3423 				payload->vcpi = req_payload.vcpi;
3424 
3425 			} else if (payload->num_slots) {
3426 				payload->num_slots = 0;
3427 				drm_dp_destroy_payload_step1(mgr, port,
3428 							     payload->vcpi,
3429 							     payload);
3430 				req_payload.payload_state =
3431 					payload->payload_state;
3432 				payload->start_slot = 0;
3433 			}
3434 			payload->payload_state = req_payload.payload_state;
3435 		}
3436 		cur_slots += req_payload.num_slots;
3437 
3438 		if (put_port)
3439 			drm_dp_mst_topology_put_port(port);
3440 	}
3441 
3442 	for (i = 0; i < mgr->max_payloads; /* do nothing */) {
3443 		if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
3444 			i++;
3445 			continue;
3446 		}
3447 
3448 		DRM_DEBUG_KMS("removing payload %d\n", i);
3449 		for (j = i; j < mgr->max_payloads - 1; j++) {
3450 			mgr->payloads[j] = mgr->payloads[j + 1];
3451 			mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
3452 
3453 			if (mgr->proposed_vcpis[j] &&
3454 			    mgr->proposed_vcpis[j]->num_slots) {
3455 				set_bit(j + 1, &mgr->payload_mask);
3456 			} else {
3457 				clear_bit(j + 1, &mgr->payload_mask);
3458 			}
3459 		}
3460 
3461 		memset(&mgr->payloads[mgr->max_payloads - 1], 0,
3462 		       sizeof(struct drm_dp_payload));
3463 		mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
3464 		clear_bit(mgr->max_payloads, &mgr->payload_mask);
3465 	}
3466 	mutex_unlock(&mgr->payload_lock);
3467 
3468 	return 0;
3469 }
3470 EXPORT_SYMBOL(drm_dp_update_payload_part1);
3471 
3472 /**
3473  * drm_dp_update_payload_part2() - Execute payload update part 2
3474  * @mgr: manager to use.
3475  *
3476  * This iterates over all proposed virtual channels, and tries to
3477  * allocate space in the link for them. For 0->slots transitions,
3478  * this step writes the remote VC payload commands. For slots->0
3479  * this just resets some internal state.
3480  */
drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr * mgr)3481 int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
3482 {
3483 	struct drm_dp_mst_port *port;
3484 	int i;
3485 	int ret = 0;
3486 
3487 	mutex_lock(&mgr->payload_lock);
3488 	for (i = 0; i < mgr->max_payloads; i++) {
3489 
3490 		if (!mgr->proposed_vcpis[i])
3491 			continue;
3492 
3493 		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
3494 
3495 		DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
3496 		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
3497 			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3498 		} else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
3499 			ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3500 		}
3501 		if (ret) {
3502 			mutex_unlock(&mgr->payload_lock);
3503 			return ret;
3504 		}
3505 	}
3506 	mutex_unlock(&mgr->payload_lock);
3507 	return 0;
3508 }
3509 EXPORT_SYMBOL(drm_dp_update_payload_part2);
3510 
drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int offset,int size,u8 * bytes)3511 static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3512 				 struct drm_dp_mst_port *port,
3513 				 int offset, int size, u8 *bytes)
3514 {
3515 	int ret = 0;
3516 	struct drm_dp_sideband_msg_tx *txmsg;
3517 	struct drm_dp_mst_branch *mstb;
3518 
3519 	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3520 	if (!mstb)
3521 		return -EINVAL;
3522 
3523 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3524 	if (!txmsg) {
3525 		ret = -ENOMEM;
3526 		goto fail_put;
3527 	}
3528 
3529 	build_dpcd_read(txmsg, port->port_num, offset, size);
3530 	txmsg->dst = port->parent;
3531 
3532 	drm_dp_queue_down_tx(mgr, txmsg);
3533 
3534 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3535 	if (ret < 0)
3536 		goto fail_free;
3537 
3538 	/* DPCD read should never be NACKed */
3539 	if (txmsg->reply.reply_type == 1) {
3540 		DRM_ERROR("mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3541 			  mstb, port->port_num, offset, size);
3542 		ret = -EIO;
3543 		goto fail_free;
3544 	}
3545 
3546 	if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3547 		ret = -EPROTO;
3548 		goto fail_free;
3549 	}
3550 
3551 	ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3552 		    size);
3553 	memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3554 
3555 fail_free:
3556 	kfree(txmsg);
3557 fail_put:
3558 	drm_dp_mst_topology_put_mstb(mstb);
3559 
3560 	return ret;
3561 }
3562 
drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int offset,int size,u8 * bytes)3563 static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3564 				  struct drm_dp_mst_port *port,
3565 				  int offset, int size, u8 *bytes)
3566 {
3567 	int ret;
3568 	struct drm_dp_sideband_msg_tx *txmsg;
3569 	struct drm_dp_mst_branch *mstb;
3570 
3571 	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3572 	if (!mstb)
3573 		return -EINVAL;
3574 
3575 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3576 	if (!txmsg) {
3577 		ret = -ENOMEM;
3578 		goto fail_put;
3579 	}
3580 
3581 	build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3582 	txmsg->dst = mstb;
3583 
3584 	drm_dp_queue_down_tx(mgr, txmsg);
3585 
3586 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3587 	if (ret > 0) {
3588 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3589 			ret = -EIO;
3590 		else
3591 			ret = size;
3592 	}
3593 
3594 	kfree(txmsg);
3595 fail_put:
3596 	drm_dp_mst_topology_put_mstb(mstb);
3597 	return ret;
3598 }
3599 
drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx * msg,u8 req_type)3600 static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3601 {
3602 	struct drm_dp_sideband_msg_reply_body reply;
3603 
3604 	reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3605 	reply.req_type = req_type;
3606 	drm_dp_encode_sideband_reply(&reply, msg);
3607 	return 0;
3608 }
3609 
drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_branch * mstb,int req_type,bool broadcast)3610 static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3611 				    struct drm_dp_mst_branch *mstb,
3612 				    int req_type, bool broadcast)
3613 {
3614 	struct drm_dp_sideband_msg_tx *txmsg;
3615 
3616 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3617 	if (!txmsg)
3618 		return -ENOMEM;
3619 
3620 	txmsg->dst = mstb;
3621 	drm_dp_encode_up_ack_reply(txmsg, req_type);
3622 
3623 	mutex_lock(&mgr->qlock);
3624 	/* construct a chunk from the first msg in the tx_msg queue */
3625 	process_single_tx_qlock(mgr, txmsg, true);
3626 	mutex_unlock(&mgr->qlock);
3627 
3628 	kfree(txmsg);
3629 	return 0;
3630 }
3631 
drm_dp_get_vc_payload_bw(u8 dp_link_bw,u8 dp_link_count)3632 static int drm_dp_get_vc_payload_bw(u8 dp_link_bw, u8  dp_link_count)
3633 {
3634 	if (dp_link_bw == 0 || dp_link_count == 0)
3635 		DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
3636 			      dp_link_bw, dp_link_count);
3637 
3638 	return dp_link_bw * dp_link_count / 2;
3639 }
3640 
3641 /**
3642  * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3643  * @aux: The DP AUX channel to use
3644  * @dpcd: A cached copy of the DPCD capabilities for this sink
3645  *
3646  * Returns: %True if the sink supports MST, %false otherwise
3647  */
drm_dp_read_mst_cap(struct drm_dp_aux * aux,const u8 dpcd[DP_RECEIVER_CAP_SIZE])3648 bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3649 			 const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3650 {
3651 	u8 mstm_cap;
3652 
3653 	if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3654 		return false;
3655 
3656 	if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3657 		return false;
3658 
3659 	return mstm_cap & DP_MST_CAP;
3660 }
3661 EXPORT_SYMBOL(drm_dp_read_mst_cap);
3662 
3663 /**
3664  * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3665  * @mgr: manager to set state for
3666  * @mst_state: true to enable MST on this connector - false to disable.
3667  *
3668  * This is called by the driver when it detects an MST capable device plugged
3669  * into a DP MST capable port, or when a DP MST capable device is unplugged.
3670  */
drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr * mgr,bool mst_state)3671 int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3672 {
3673 	int ret = 0;
3674 	struct drm_dp_mst_branch *mstb = NULL;
3675 
3676 	mutex_lock(&mgr->payload_lock);
3677 	mutex_lock(&mgr->lock);
3678 	if (mst_state == mgr->mst_state)
3679 		goto out_unlock;
3680 
3681 	mgr->mst_state = mst_state;
3682 	/* set the device into MST mode */
3683 	if (mst_state) {
3684 		struct drm_dp_payload reset_pay;
3685 
3686 		WARN_ON(mgr->mst_primary);
3687 
3688 		/* get dpcd info */
3689 		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
3690 		if (ret != DP_RECEIVER_CAP_SIZE) {
3691 			DRM_DEBUG_KMS("failed to read DPCD\n");
3692 			goto out_unlock;
3693 		}
3694 
3695 		mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr->dpcd[1],
3696 							mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK);
3697 		if (mgr->pbn_div == 0) {
3698 			ret = -EINVAL;
3699 			goto out_unlock;
3700 		}
3701 
3702 		/* add initial branch device at LCT 1 */
3703 		mstb = drm_dp_add_mst_branch_device(1, NULL);
3704 		if (mstb == NULL) {
3705 			ret = -ENOMEM;
3706 			goto out_unlock;
3707 		}
3708 		mstb->mgr = mgr;
3709 
3710 		/* give this the main reference */
3711 		mgr->mst_primary = mstb;
3712 		drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3713 
3714 		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3715 					 DP_MST_EN |
3716 					 DP_UP_REQ_EN |
3717 					 DP_UPSTREAM_IS_SRC);
3718 		if (ret < 0)
3719 			goto out_unlock;
3720 
3721 		reset_pay.start_slot = 0;
3722 		reset_pay.num_slots = 0x3f;
3723 		drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
3724 
3725 		queue_work(system_long_wq, &mgr->work);
3726 
3727 		ret = 0;
3728 	} else {
3729 		/* disable MST on the device */
3730 		mstb = mgr->mst_primary;
3731 		mgr->mst_primary = NULL;
3732 		/* this can fail if the device is gone */
3733 		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3734 		ret = 0;
3735 		memset(mgr->payloads, 0,
3736 		       mgr->max_payloads * sizeof(mgr->payloads[0]));
3737 		memset(mgr->proposed_vcpis, 0,
3738 		       mgr->max_payloads * sizeof(mgr->proposed_vcpis[0]));
3739 		mgr->payload_mask = 0;
3740 		set_bit(0, &mgr->payload_mask);
3741 		mgr->vcpi_mask = 0;
3742 		mgr->payload_id_table_cleared = false;
3743 	}
3744 
3745 out_unlock:
3746 	mutex_unlock(&mgr->lock);
3747 	mutex_unlock(&mgr->payload_lock);
3748 	if (mstb)
3749 		drm_dp_mst_topology_put_mstb(mstb);
3750 	return ret;
3751 
3752 }
3753 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3754 
3755 static void
drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch * mstb)3756 drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3757 {
3758 	struct drm_dp_mst_port *port;
3759 
3760 	/* The link address will need to be re-sent on resume */
3761 	mstb->link_address_sent = false;
3762 
3763 	list_for_each_entry(port, &mstb->ports, next)
3764 		if (port->mstb)
3765 			drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3766 }
3767 
3768 /**
3769  * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3770  * @mgr: manager to suspend
3771  *
3772  * This function tells the MST device that we can't handle UP messages
3773  * anymore. This should stop it from sending any since we are suspended.
3774  */
drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr * mgr)3775 void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3776 {
3777 	mutex_lock(&mgr->lock);
3778 	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3779 			   DP_MST_EN | DP_UPSTREAM_IS_SRC);
3780 	mutex_unlock(&mgr->lock);
3781 	flush_work(&mgr->up_req_work);
3782 	flush_work(&mgr->work);
3783 	flush_work(&mgr->delayed_destroy_work);
3784 
3785 	mutex_lock(&mgr->lock);
3786 	if (mgr->mst_state && mgr->mst_primary)
3787 		drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3788 	mutex_unlock(&mgr->lock);
3789 }
3790 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3791 
3792 /**
3793  * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3794  * @mgr: manager to resume
3795  * @sync: whether or not to perform topology reprobing synchronously
3796  *
3797  * This will fetch DPCD and see if the device is still there,
3798  * if it is, it will rewrite the MSTM control bits, and return.
3799  *
3800  * If the device fails this returns -1, and the driver should do
3801  * a full MST reprobe, in case we were undocked.
3802  *
3803  * During system resume (where it is assumed that the driver will be calling
3804  * drm_atomic_helper_resume()) this function should be called beforehand with
3805  * @sync set to true. In contexts like runtime resume where the driver is not
3806  * expected to be calling drm_atomic_helper_resume(), this function should be
3807  * called with @sync set to false in order to avoid deadlocking.
3808  *
3809  * Returns: -1 if the MST topology was removed while we were suspended, 0
3810  * otherwise.
3811  */
drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr * mgr,bool sync)3812 int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3813 				   bool sync)
3814 {
3815 	int ret;
3816 	u8 guid[16];
3817 
3818 	mutex_lock(&mgr->lock);
3819 	if (!mgr->mst_primary)
3820 		goto out_fail;
3821 
3822 	ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd,
3823 			       DP_RECEIVER_CAP_SIZE);
3824 	if (ret != DP_RECEIVER_CAP_SIZE) {
3825 		DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
3826 		goto out_fail;
3827 	}
3828 
3829 	ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3830 				 DP_MST_EN |
3831 				 DP_UP_REQ_EN |
3832 				 DP_UPSTREAM_IS_SRC);
3833 	if (ret < 0) {
3834 		DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
3835 		goto out_fail;
3836 	}
3837 
3838 	/* Some hubs forget their guids after they resume */
3839 	ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3840 	if (ret != 16) {
3841 		DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
3842 		goto out_fail;
3843 	}
3844 
3845 	ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3846 	if (ret) {
3847 		DRM_DEBUG_KMS("check mstb failed - undocked during suspend?\n");
3848 		goto out_fail;
3849 	}
3850 
3851 	/*
3852 	 * For the final step of resuming the topology, we need to bring the
3853 	 * state of our in-memory topology back into sync with reality. So,
3854 	 * restart the probing process as if we're probing a new hub
3855 	 */
3856 	queue_work(system_long_wq, &mgr->work);
3857 	mutex_unlock(&mgr->lock);
3858 
3859 	if (sync) {
3860 		DRM_DEBUG_KMS("Waiting for link probe work to finish re-syncing topology...\n");
3861 		flush_work(&mgr->work);
3862 	}
3863 
3864 	return 0;
3865 
3866 out_fail:
3867 	mutex_unlock(&mgr->lock);
3868 	return -1;
3869 }
3870 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3871 
3872 static bool
drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr * mgr,bool up,struct drm_dp_mst_branch ** mstb)3873 drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3874 		      struct drm_dp_mst_branch **mstb)
3875 {
3876 	int len;
3877 	u8 replyblock[32];
3878 	int replylen, curreply;
3879 	int ret;
3880 	u8 hdrlen;
3881 	struct drm_dp_sideband_msg_hdr hdr;
3882 	struct drm_dp_sideband_msg_rx *msg =
3883 		up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3884 	int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3885 			   DP_SIDEBAND_MSG_DOWN_REP_BASE;
3886 
3887 	if (!up)
3888 		*mstb = NULL;
3889 
3890 	len = min(mgr->max_dpcd_transaction_bytes, 16);
3891 	ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3892 	if (ret != len) {
3893 		DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
3894 		return false;
3895 	}
3896 
3897 	ret = drm_dp_decode_sideband_msg_hdr(&hdr, replyblock, len, &hdrlen);
3898 	if (ret == false) {
3899 		print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3900 			       1, replyblock, len, false);
3901 		DRM_DEBUG_KMS("ERROR: failed header\n");
3902 		return false;
3903 	}
3904 
3905 	if (!up) {
3906 		/* Caller is responsible for giving back this reference */
3907 		*mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3908 		if (!*mstb) {
3909 			DRM_DEBUG_KMS("Got MST reply from unknown device %d\n",
3910 				      hdr.lct);
3911 			return false;
3912 		}
3913 	}
3914 
3915 	if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3916 		DRM_DEBUG_KMS("sideband msg set header failed %d\n",
3917 			      replyblock[0]);
3918 		return false;
3919 	}
3920 
3921 	replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3922 	ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3923 	if (!ret) {
3924 		DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
3925 		return false;
3926 	}
3927 
3928 	replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3929 	curreply = len;
3930 	while (replylen > 0) {
3931 		len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3932 		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3933 				    replyblock, len);
3934 		if (ret != len) {
3935 			DRM_DEBUG_KMS("failed to read a chunk (len %d, ret %d)\n",
3936 				      len, ret);
3937 			return false;
3938 		}
3939 
3940 		ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3941 		if (!ret) {
3942 			DRM_DEBUG_KMS("failed to build sideband msg\n");
3943 			return false;
3944 		}
3945 
3946 		curreply += len;
3947 		replylen -= len;
3948 	}
3949 	return true;
3950 }
3951 
drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr * mgr)3952 static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3953 {
3954 	struct drm_dp_sideband_msg_tx *txmsg;
3955 	struct drm_dp_mst_branch *mstb = NULL;
3956 	struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3957 
3958 	if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3959 		goto out;
3960 
3961 	/* Multi-packet message transmission, don't clear the reply */
3962 	if (!msg->have_eomt)
3963 		goto out;
3964 
3965 	/* find the message */
3966 	mutex_lock(&mgr->qlock);
3967 	txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
3968 					 struct drm_dp_sideband_msg_tx, next);
3969 	mutex_unlock(&mgr->qlock);
3970 
3971 	/* Were we actually expecting a response, and from this mstb? */
3972 	if (!txmsg || txmsg->dst != mstb) {
3973 		struct drm_dp_sideband_msg_hdr *hdr;
3974 
3975 		hdr = &msg->initial_hdr;
3976 		DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
3977 			      mstb, hdr->seqno, hdr->lct, hdr->rad[0],
3978 			      msg->msg[0]);
3979 		goto out_clear_reply;
3980 	}
3981 
3982 	drm_dp_sideband_parse_reply(msg, &txmsg->reply);
3983 
3984 	if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3985 		DRM_DEBUG_KMS("Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
3986 			      txmsg->reply.req_type,
3987 			      drm_dp_mst_req_type_str(txmsg->reply.req_type),
3988 			      txmsg->reply.u.nak.reason,
3989 			      drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
3990 			      txmsg->reply.u.nak.nak_data);
3991 	}
3992 
3993 	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3994 	drm_dp_mst_topology_put_mstb(mstb);
3995 
3996 	mutex_lock(&mgr->qlock);
3997 	txmsg->state = DRM_DP_SIDEBAND_TX_RX;
3998 	list_del(&txmsg->next);
3999 	mutex_unlock(&mgr->qlock);
4000 
4001 	wake_up_all(&mgr->tx_waitq);
4002 
4003 	return 0;
4004 
4005 out_clear_reply:
4006 	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4007 out:
4008 	if (mstb)
4009 		drm_dp_mst_topology_put_mstb(mstb);
4010 
4011 	return 0;
4012 }
4013 
4014 static inline bool
drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_pending_up_req * up_req)4015 drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
4016 			  struct drm_dp_pending_up_req *up_req)
4017 {
4018 	struct drm_dp_mst_branch *mstb = NULL;
4019 	struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
4020 	struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
4021 	bool hotplug = false;
4022 
4023 	if (hdr->broadcast) {
4024 		const u8 *guid = NULL;
4025 
4026 		if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
4027 			guid = msg->u.conn_stat.guid;
4028 		else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
4029 			guid = msg->u.resource_stat.guid;
4030 
4031 		if (guid)
4032 			mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
4033 	} else {
4034 		mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
4035 	}
4036 
4037 	if (!mstb) {
4038 		DRM_DEBUG_KMS("Got MST reply from unknown device %d\n",
4039 			      hdr->lct);
4040 		return false;
4041 	}
4042 
4043 	/* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
4044 	if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
4045 		drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
4046 		hotplug = true;
4047 	}
4048 
4049 	drm_dp_mst_topology_put_mstb(mstb);
4050 	return hotplug;
4051 }
4052 
drm_dp_mst_up_req_work(struct work_struct * work)4053 static void drm_dp_mst_up_req_work(struct work_struct *work)
4054 {
4055 	struct drm_dp_mst_topology_mgr *mgr =
4056 		container_of(work, struct drm_dp_mst_topology_mgr,
4057 			     up_req_work);
4058 	struct drm_dp_pending_up_req *up_req;
4059 	bool send_hotplug = false;
4060 
4061 	mutex_lock(&mgr->probe_lock);
4062 	while (true) {
4063 		mutex_lock(&mgr->up_req_lock);
4064 		up_req = list_first_entry_or_null(&mgr->up_req_list,
4065 						  struct drm_dp_pending_up_req,
4066 						  next);
4067 		if (up_req)
4068 			list_del(&up_req->next);
4069 		mutex_unlock(&mgr->up_req_lock);
4070 
4071 		if (!up_req)
4072 			break;
4073 
4074 		send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
4075 		kfree(up_req);
4076 	}
4077 	mutex_unlock(&mgr->probe_lock);
4078 
4079 	if (send_hotplug)
4080 		drm_kms_helper_hotplug_event(mgr->dev);
4081 }
4082 
drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr * mgr)4083 static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
4084 {
4085 	struct drm_dp_pending_up_req *up_req;
4086 
4087 	if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4088 		goto out;
4089 
4090 	if (!mgr->up_req_recv.have_eomt)
4091 		return 0;
4092 
4093 	up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4094 	if (!up_req) {
4095 		DRM_ERROR("Not enough memory to process MST up req\n");
4096 		return -ENOMEM;
4097 	}
4098 	INIT_LIST_HEAD(&up_req->next);
4099 
4100 	drm_dp_sideband_parse_req(&mgr->up_req_recv, &up_req->msg);
4101 
4102 	if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4103 	    up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4104 		DRM_DEBUG_KMS("Received unknown up req type, ignoring: %x\n",
4105 			      up_req->msg.req_type);
4106 		kfree(up_req);
4107 		goto out;
4108 	}
4109 
4110 	drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4111 				 false);
4112 
4113 	if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4114 		const struct drm_dp_connection_status_notify *conn_stat =
4115 			&up_req->msg.u.conn_stat;
4116 
4117 		DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4118 			      conn_stat->port_number,
4119 			      conn_stat->legacy_device_plug_status,
4120 			      conn_stat->displayport_device_plug_status,
4121 			      conn_stat->message_capability_status,
4122 			      conn_stat->input_port,
4123 			      conn_stat->peer_device_type);
4124 	} else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4125 		const struct drm_dp_resource_status_notify *res_stat =
4126 			&up_req->msg.u.resource_stat;
4127 
4128 		DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n",
4129 			      res_stat->port_number,
4130 			      res_stat->available_pbn);
4131 	}
4132 
4133 	up_req->hdr = mgr->up_req_recv.initial_hdr;
4134 	mutex_lock(&mgr->up_req_lock);
4135 	list_add_tail(&up_req->next, &mgr->up_req_list);
4136 	mutex_unlock(&mgr->up_req_lock);
4137 	queue_work(system_long_wq, &mgr->up_req_work);
4138 
4139 out:
4140 	memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4141 	return 0;
4142 }
4143 
4144 /**
4145  * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
4146  * @mgr: manager to notify irq for.
4147  * @esi: 4 bytes from SINK_COUNT_ESI
4148  * @handled: whether the hpd interrupt was consumed or not
4149  *
4150  * This should be called from the driver when it detects a short IRQ,
4151  * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4152  * topology manager will process the sideband messages received as a result
4153  * of this.
4154  */
drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr * mgr,u8 * esi,bool * handled)4155 int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
4156 {
4157 	int ret = 0;
4158 	int sc;
4159 	*handled = false;
4160 	sc = esi[0] & 0x3f;
4161 
4162 	if (sc != mgr->sink_count) {
4163 		mgr->sink_count = sc;
4164 		*handled = true;
4165 	}
4166 
4167 	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4168 		ret = drm_dp_mst_handle_down_rep(mgr);
4169 		*handled = true;
4170 	}
4171 
4172 	if (esi[1] & DP_UP_REQ_MSG_RDY) {
4173 		ret |= drm_dp_mst_handle_up_req(mgr);
4174 		*handled = true;
4175 	}
4176 
4177 	drm_dp_mst_kick_tx(mgr);
4178 	return ret;
4179 }
4180 EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
4181 
4182 /**
4183  * drm_dp_mst_detect_port() - get connection status for an MST port
4184  * @connector: DRM connector for this port
4185  * @ctx: The acquisition context to use for grabbing locks
4186  * @mgr: manager for this port
4187  * @port: pointer to a port
4188  *
4189  * This returns the current connection state for a port.
4190  */
4191 int
drm_dp_mst_detect_port(struct drm_connector * connector,struct drm_modeset_acquire_ctx * ctx,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4192 drm_dp_mst_detect_port(struct drm_connector *connector,
4193 		       struct drm_modeset_acquire_ctx *ctx,
4194 		       struct drm_dp_mst_topology_mgr *mgr,
4195 		       struct drm_dp_mst_port *port)
4196 {
4197 	int ret;
4198 
4199 	/* we need to search for the port in the mgr in case it's gone */
4200 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4201 	if (!port)
4202 		return connector_status_disconnected;
4203 
4204 	ret = drm_modeset_lock(&mgr->base.lock, ctx);
4205 	if (ret)
4206 		goto out;
4207 
4208 	ret = connector_status_disconnected;
4209 
4210 	if (!port->ddps)
4211 		goto out;
4212 
4213 	switch (port->pdt) {
4214 	case DP_PEER_DEVICE_NONE:
4215 	case DP_PEER_DEVICE_MST_BRANCHING:
4216 		if (!port->mcs)
4217 			ret = connector_status_connected;
4218 		break;
4219 
4220 	case DP_PEER_DEVICE_SST_SINK:
4221 		ret = connector_status_connected;
4222 		/* for logical ports - cache the EDID */
4223 		if (port->port_num >= 8 && !port->cached_edid) {
4224 			port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
4225 		}
4226 		break;
4227 	case DP_PEER_DEVICE_DP_LEGACY_CONV:
4228 		if (port->ldps)
4229 			ret = connector_status_connected;
4230 		break;
4231 	}
4232 out:
4233 	drm_dp_mst_topology_put_port(port);
4234 	return ret;
4235 }
4236 EXPORT_SYMBOL(drm_dp_mst_detect_port);
4237 
4238 /**
4239  * drm_dp_mst_get_edid() - get EDID for an MST port
4240  * @connector: toplevel connector to get EDID for
4241  * @mgr: manager for this port
4242  * @port: unverified pointer to a port.
4243  *
4244  * This returns an EDID for the port connected to a connector,
4245  * It validates the pointer still exists so the caller doesn't require a
4246  * reference.
4247  */
drm_dp_mst_get_edid(struct drm_connector * connector,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4248 struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4249 {
4250 	struct edid *edid = NULL;
4251 
4252 	/* we need to search for the port in the mgr in case it's gone */
4253 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4254 	if (!port)
4255 		return NULL;
4256 
4257 	if (port->cached_edid)
4258 		edid = drm_edid_duplicate(port->cached_edid);
4259 	else {
4260 		edid = drm_get_edid(connector, &port->aux.ddc);
4261 	}
4262 	port->has_audio = drm_detect_monitor_audio(edid);
4263 	drm_dp_mst_topology_put_port(port);
4264 	return edid;
4265 }
4266 EXPORT_SYMBOL(drm_dp_mst_get_edid);
4267 
4268 /**
4269  * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
4270  * @mgr: manager to use
4271  * @pbn: payload bandwidth to convert into slots.
4272  *
4273  * Calculate the number of VCPI slots that will be required for the given PBN
4274  * value. This function is deprecated, and should not be used in atomic
4275  * drivers.
4276  *
4277  * RETURNS:
4278  * The total slots required for this port, or error.
4279  */
drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr * mgr,int pbn)4280 int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
4281 			   int pbn)
4282 {
4283 	int num_slots;
4284 
4285 	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
4286 
4287 	/* max. time slots - one slot for MTP header */
4288 	if (num_slots > 63)
4289 		return -ENOSPC;
4290 	return num_slots;
4291 }
4292 EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
4293 
drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_vcpi * vcpi,int pbn,int slots)4294 static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4295 			    struct drm_dp_vcpi *vcpi, int pbn, int slots)
4296 {
4297 	int ret;
4298 
4299 	/* max. time slots - one slot for MTP header */
4300 	if (slots > 63)
4301 		return -ENOSPC;
4302 
4303 	vcpi->pbn = pbn;
4304 	vcpi->aligned_pbn = slots * mgr->pbn_div;
4305 	vcpi->num_slots = slots;
4306 
4307 	ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
4308 	if (ret < 0)
4309 		return ret;
4310 	return 0;
4311 }
4312 
4313 /**
4314  * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
4315  * @state: global atomic state
4316  * @mgr: MST topology manager for the port
4317  * @port: port to find vcpi slots for
4318  * @pbn: bandwidth required for the mode in PBN
4319  * @pbn_div: divider for DSC mode that takes FEC into account
4320  *
4321  * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
4322  * may have had. Any atomic drivers which support MST must call this function
4323  * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
4324  * current VCPI allocation for the new state, but only when
4325  * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
4326  * to ensure compatibility with userspace applications that still use the
4327  * legacy modesetting UAPI.
4328  *
4329  * Allocations set by this function are not checked against the bandwidth
4330  * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4331  *
4332  * Additionally, it is OK to call this function multiple times on the same
4333  * @port as needed. It is not OK however, to call this function and
4334  * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
4335  *
4336  * See also:
4337  * drm_dp_atomic_release_vcpi_slots()
4338  * drm_dp_mst_atomic_check()
4339  *
4340  * Returns:
4341  * Total slots in the atomic state assigned for this port, or a negative error
4342  * code if the port no longer exists
4343  */
drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int pbn,int pbn_div)4344 int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
4345 				  struct drm_dp_mst_topology_mgr *mgr,
4346 				  struct drm_dp_mst_port *port, int pbn,
4347 				  int pbn_div)
4348 {
4349 	struct drm_dp_mst_topology_state *topology_state;
4350 	struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
4351 	int prev_slots, prev_bw, req_slots;
4352 
4353 	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4354 	if (IS_ERR(topology_state))
4355 		return PTR_ERR(topology_state);
4356 
4357 	/* Find the current allocation for this port, if any */
4358 	list_for_each_entry(pos, &topology_state->vcpis, next) {
4359 		if (pos->port == port) {
4360 			vcpi = pos;
4361 			prev_slots = vcpi->vcpi;
4362 			prev_bw = vcpi->pbn;
4363 
4364 			/*
4365 			 * This should never happen, unless the driver tries
4366 			 * releasing and allocating the same VCPI allocation,
4367 			 * which is an error
4368 			 */
4369 			if (WARN_ON(!prev_slots)) {
4370 				DRM_ERROR("cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
4371 					  port);
4372 				return -EINVAL;
4373 			}
4374 
4375 			break;
4376 		}
4377 	}
4378 	if (!vcpi) {
4379 		prev_slots = 0;
4380 		prev_bw = 0;
4381 	}
4382 
4383 	if (pbn_div <= 0)
4384 		pbn_div = mgr->pbn_div;
4385 
4386 	req_slots = DIV_ROUND_UP(pbn, pbn_div);
4387 
4388 	DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
4389 			 port->connector->base.id, port->connector->name,
4390 			 port, prev_slots, req_slots);
4391 	DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4392 			 port->connector->base.id, port->connector->name,
4393 			 port, prev_bw, pbn);
4394 
4395 	/* Add the new allocation to the state */
4396 	if (!vcpi) {
4397 		vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
4398 		if (!vcpi)
4399 			return -ENOMEM;
4400 
4401 		drm_dp_mst_get_port_malloc(port);
4402 		vcpi->port = port;
4403 		list_add(&vcpi->next, &topology_state->vcpis);
4404 	}
4405 	vcpi->vcpi = req_slots;
4406 	vcpi->pbn = pbn;
4407 
4408 	return req_slots;
4409 }
4410 EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
4411 
4412 /**
4413  * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
4414  * @state: global atomic state
4415  * @mgr: MST topology manager for the port
4416  * @port: The port to release the VCPI slots from
4417  *
4418  * Releases any VCPI slots that have been allocated to a port in the atomic
4419  * state. Any atomic drivers which support MST must call this function in
4420  * their &drm_connector_helper_funcs.atomic_check() callback when the
4421  * connector will no longer have VCPI allocated (e.g. because its CRTC was
4422  * removed) when it had VCPI allocated in the previous atomic state.
4423  *
4424  * It is OK to call this even if @port has been removed from the system.
4425  * Additionally, it is OK to call this function multiple times on the same
4426  * @port as needed. It is not OK however, to call this function and
4427  * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
4428  * phase.
4429  *
4430  * See also:
4431  * drm_dp_atomic_find_vcpi_slots()
4432  * drm_dp_mst_atomic_check()
4433  *
4434  * Returns:
4435  * 0 if all slots for this port were added back to
4436  * &drm_dp_mst_topology_state.avail_slots or negative error code
4437  */
drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4438 int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
4439 				     struct drm_dp_mst_topology_mgr *mgr,
4440 				     struct drm_dp_mst_port *port)
4441 {
4442 	struct drm_dp_mst_topology_state *topology_state;
4443 	struct drm_dp_vcpi_allocation *pos;
4444 	bool found = false;
4445 
4446 	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4447 	if (IS_ERR(topology_state))
4448 		return PTR_ERR(topology_state);
4449 
4450 	list_for_each_entry(pos, &topology_state->vcpis, next) {
4451 		if (pos->port == port) {
4452 			found = true;
4453 			break;
4454 		}
4455 	}
4456 	if (WARN_ON(!found)) {
4457 		DRM_ERROR("no VCPI for [MST PORT:%p] found in mst state %p\n",
4458 			  port, &topology_state->base);
4459 		return -EINVAL;
4460 	}
4461 
4462 	DRM_DEBUG_ATOMIC("[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
4463 	if (pos->vcpi) {
4464 		drm_dp_mst_put_port_malloc(port);
4465 		pos->vcpi = 0;
4466 		pos->pbn = 0;
4467 	}
4468 
4469 	return 0;
4470 }
4471 EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
4472 
4473 /**
4474  * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
4475  * @mgr: manager for this port
4476  * @port: port to allocate a virtual channel for.
4477  * @pbn: payload bandwidth number to request
4478  * @slots: returned number of slots for this PBN.
4479  */
drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,int pbn,int slots)4480 bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4481 			      struct drm_dp_mst_port *port, int pbn, int slots)
4482 {
4483 	int ret;
4484 
4485 	if (slots < 0)
4486 		return false;
4487 
4488 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4489 	if (!port)
4490 		return false;
4491 
4492 	if (port->vcpi.vcpi > 0) {
4493 		DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
4494 			      port->vcpi.vcpi, port->vcpi.pbn, pbn);
4495 		if (pbn == port->vcpi.pbn) {
4496 			drm_dp_mst_topology_put_port(port);
4497 			return true;
4498 		}
4499 	}
4500 
4501 	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
4502 	if (ret) {
4503 		DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n",
4504 			      DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
4505 		drm_dp_mst_topology_put_port(port);
4506 		goto out;
4507 	}
4508 	DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n",
4509 		      pbn, port->vcpi.num_slots);
4510 
4511 	/* Keep port allocated until its payload has been removed */
4512 	drm_dp_mst_get_port_malloc(port);
4513 	drm_dp_mst_topology_put_port(port);
4514 	return true;
4515 out:
4516 	return false;
4517 }
4518 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
4519 
drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4520 int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4521 {
4522 	int slots = 0;
4523 
4524 	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4525 	if (!port)
4526 		return slots;
4527 
4528 	slots = port->vcpi.num_slots;
4529 	drm_dp_mst_topology_put_port(port);
4530 	return slots;
4531 }
4532 EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
4533 
4534 /**
4535  * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
4536  * @mgr: manager for this port
4537  * @port: unverified pointer to a port.
4538  *
4539  * This just resets the number of slots for the ports VCPI for later programming.
4540  */
drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4541 void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4542 {
4543 	/*
4544 	 * A port with VCPI will remain allocated until its VCPI is
4545 	 * released, no verified ref needed
4546 	 */
4547 
4548 	port->vcpi.num_slots = 0;
4549 }
4550 EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
4551 
4552 /**
4553  * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
4554  * @mgr: manager for this port
4555  * @port: port to deallocate vcpi for
4556  *
4557  * This can be called unconditionally, regardless of whether
4558  * drm_dp_mst_allocate_vcpi() succeeded or not.
4559  */
drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port)4560 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4561 				struct drm_dp_mst_port *port)
4562 {
4563 	if (!port->vcpi.vcpi)
4564 		return;
4565 
4566 	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
4567 	port->vcpi.num_slots = 0;
4568 	port->vcpi.pbn = 0;
4569 	port->vcpi.aligned_pbn = 0;
4570 	port->vcpi.vcpi = 0;
4571 	drm_dp_mst_put_port_malloc(port);
4572 }
4573 EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
4574 
drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr * mgr,int id,struct drm_dp_payload * payload)4575 static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4576 				     int id, struct drm_dp_payload *payload)
4577 {
4578 	u8 payload_alloc[3], status;
4579 	int ret;
4580 	int retries = 0;
4581 
4582 	drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4583 			   DP_PAYLOAD_TABLE_UPDATED);
4584 
4585 	payload_alloc[0] = id;
4586 	payload_alloc[1] = payload->start_slot;
4587 	payload_alloc[2] = payload->num_slots;
4588 
4589 	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4590 	if (ret != 3) {
4591 		DRM_DEBUG_KMS("failed to write payload allocation %d\n", ret);
4592 		goto fail;
4593 	}
4594 
4595 retry:
4596 	ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4597 	if (ret < 0) {
4598 		DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
4599 		goto fail;
4600 	}
4601 
4602 	if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4603 		retries++;
4604 		if (retries < 20) {
4605 			usleep_range(10000, 20000);
4606 			goto retry;
4607 		}
4608 		DRM_DEBUG_KMS("status not set after read payload table status %d\n", status);
4609 		ret = -EINVAL;
4610 		goto fail;
4611 	}
4612 	ret = 0;
4613 fail:
4614 	return ret;
4615 }
4616 
do_get_act_status(struct drm_dp_aux * aux)4617 static int do_get_act_status(struct drm_dp_aux *aux)
4618 {
4619 	int ret;
4620 	u8 status;
4621 
4622 	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4623 	if (ret < 0)
4624 		return ret;
4625 
4626 	return status;
4627 }
4628 
4629 /**
4630  * drm_dp_check_act_status() - Polls for ACT handled status.
4631  * @mgr: manager to use
4632  *
4633  * Tries waiting for the MST hub to finish updating it's payload table by
4634  * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4635  * take that long).
4636  *
4637  * Returns:
4638  * 0 if the ACT was handled in time, negative error code on failure.
4639  */
drm_dp_check_act_status(struct drm_dp_mst_topology_mgr * mgr)4640 int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4641 {
4642 	/*
4643 	 * There doesn't seem to be any recommended retry count or timeout in
4644 	 * the MST specification. Since some hubs have been observed to take
4645 	 * over 1 second to update their payload allocations under certain
4646 	 * conditions, we use a rather large timeout value.
4647 	 */
4648 	const int timeout_ms = 3000;
4649 	int ret, status;
4650 
4651 	ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4652 				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4653 				 200, timeout_ms * USEC_PER_MSEC);
4654 	if (ret < 0 && status >= 0) {
4655 		DRM_ERROR("Failed to get ACT after %dms, last status: %02x\n",
4656 			  timeout_ms, status);
4657 		return -EINVAL;
4658 	} else if (status < 0) {
4659 		/*
4660 		 * Failure here isn't unexpected - the hub may have
4661 		 * just been unplugged
4662 		 */
4663 		DRM_DEBUG_KMS("Failed to read payload table status: %d\n",
4664 			      status);
4665 		return status;
4666 	}
4667 
4668 	return 0;
4669 }
4670 EXPORT_SYMBOL(drm_dp_check_act_status);
4671 
4672 /**
4673  * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4674  * @clock: dot clock for the mode
4675  * @bpp: bpp for the mode.
4676  * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
4677  *
4678  * This uses the formula in the spec to calculate the PBN value for a mode.
4679  */
drm_dp_calc_pbn_mode(int clock,int bpp,bool dsc)4680 int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
4681 {
4682 	/*
4683 	 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
4684 	 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4685 	 * common multiplier to render an integer PBN for all link rate/lane
4686 	 * counts combinations
4687 	 * calculate
4688 	 * peak_kbps *= (1006/1000)
4689 	 * peak_kbps *= (64/54)
4690 	 * peak_kbps *= 8    convert to bytes
4691 	 *
4692 	 * If the bpp is in units of 1/16, further divide by 16. Put this
4693 	 * factor in the numerator rather than the denominator to avoid
4694 	 * integer overflow
4695 	 */
4696 
4697 	if (dsc)
4698 		return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
4699 					8 * 54 * 1000 * 1000);
4700 
4701 	return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
4702 				8 * 54 * 1000 * 1000);
4703 }
4704 EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4705 
4706 /* we want to kick the TX after we've ack the up/down IRQs. */
drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr * mgr)4707 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4708 {
4709 	queue_work(system_long_wq, &mgr->tx_work);
4710 }
4711 
drm_dp_mst_dump_mstb(struct seq_file * m,struct drm_dp_mst_branch * mstb)4712 static void drm_dp_mst_dump_mstb(struct seq_file *m,
4713 				 struct drm_dp_mst_branch *mstb)
4714 {
4715 	struct drm_dp_mst_port *port;
4716 	int tabs = mstb->lct;
4717 	char prefix[10];
4718 	int i;
4719 
4720 	for (i = 0; i < tabs; i++)
4721 		prefix[i] = '\t';
4722 	prefix[i] = '\0';
4723 
4724 	seq_printf(m, "%smst: %p, %d\n", prefix, mstb, mstb->num_ports);
4725 	list_for_each_entry(port, &mstb->ports, next) {
4726 		seq_printf(m, "%sport: %d: input: %d: pdt: %d, ddps: %d ldps: %d, sdp: %d/%d, %p, conn: %p\n", prefix, port->port_num, port->input, port->pdt, port->ddps, port->ldps, port->num_sdp_streams, port->num_sdp_stream_sinks, port, port->connector);
4727 		if (port->mstb)
4728 			drm_dp_mst_dump_mstb(m, port->mstb);
4729 	}
4730 }
4731 
4732 #define DP_PAYLOAD_TABLE_SIZE		64
4733 
dump_dp_payload_table(struct drm_dp_mst_topology_mgr * mgr,char * buf)4734 static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4735 				  char *buf)
4736 {
4737 	int i;
4738 
4739 	for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4740 		if (drm_dp_dpcd_read(mgr->aux,
4741 				     DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4742 				     &buf[i], 16) != 16)
4743 			return false;
4744 	}
4745 	return true;
4746 }
4747 
fetch_monitor_name(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_port * port,char * name,int namelen)4748 static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4749 			       struct drm_dp_mst_port *port, char *name,
4750 			       int namelen)
4751 {
4752 	struct edid *mst_edid;
4753 
4754 	mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4755 	drm_edid_get_monitor_name(mst_edid, name, namelen);
4756 }
4757 
4758 /**
4759  * drm_dp_mst_dump_topology(): dump topology to seq file.
4760  * @m: seq_file to dump output to
4761  * @mgr: manager to dump current topology for.
4762  *
4763  * helper to dump MST topology to a seq file for debugfs.
4764  */
drm_dp_mst_dump_topology(struct seq_file * m,struct drm_dp_mst_topology_mgr * mgr)4765 void drm_dp_mst_dump_topology(struct seq_file *m,
4766 			      struct drm_dp_mst_topology_mgr *mgr)
4767 {
4768 	int i;
4769 	struct drm_dp_mst_port *port;
4770 
4771 	mutex_lock(&mgr->lock);
4772 	if (mgr->mst_primary)
4773 		drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4774 
4775 	/* dump VCPIs */
4776 	mutex_unlock(&mgr->lock);
4777 
4778 	mutex_lock(&mgr->payload_lock);
4779 	seq_printf(m, "vcpi: %lx %lx %d\n", mgr->payload_mask, mgr->vcpi_mask,
4780 		mgr->max_payloads);
4781 
4782 	for (i = 0; i < mgr->max_payloads; i++) {
4783 		if (mgr->proposed_vcpis[i]) {
4784 			char name[14];
4785 
4786 			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
4787 			fetch_monitor_name(mgr, port, name, sizeof(name));
4788 			seq_printf(m, "vcpi %d: %d %d %d sink name: %s\n", i,
4789 				   port->port_num, port->vcpi.vcpi,
4790 				   port->vcpi.num_slots,
4791 				   (*name != 0) ? name :  "Unknown");
4792 		} else
4793 			seq_printf(m, "vcpi %d:unused\n", i);
4794 	}
4795 	for (i = 0; i < mgr->max_payloads; i++) {
4796 		seq_printf(m, "payload %d: %d, %d, %d\n",
4797 			   i,
4798 			   mgr->payloads[i].payload_state,
4799 			   mgr->payloads[i].start_slot,
4800 			   mgr->payloads[i].num_slots);
4801 
4802 
4803 	}
4804 	mutex_unlock(&mgr->payload_lock);
4805 
4806 	mutex_lock(&mgr->lock);
4807 	if (mgr->mst_primary) {
4808 		u8 buf[DP_PAYLOAD_TABLE_SIZE];
4809 		int ret;
4810 
4811 		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
4812 		if (ret) {
4813 			seq_printf(m, "dpcd read failed\n");
4814 			goto out;
4815 		}
4816 		seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4817 
4818 		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4819 		if (ret) {
4820 			seq_printf(m, "faux/mst read failed\n");
4821 			goto out;
4822 		}
4823 		seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4824 
4825 		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4826 		if (ret) {
4827 			seq_printf(m, "mst ctrl read failed\n");
4828 			goto out;
4829 		}
4830 		seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4831 
4832 		/* dump the standard OUI branch header */
4833 		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4834 		if (ret) {
4835 			seq_printf(m, "branch oui read failed\n");
4836 			goto out;
4837 		}
4838 		seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4839 
4840 		for (i = 0x3; i < 0x8 && buf[i]; i++)
4841 			seq_printf(m, "%c", buf[i]);
4842 		seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4843 			   buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4844 		if (dump_dp_payload_table(mgr, buf))
4845 			seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4846 	}
4847 
4848 out:
4849 	mutex_unlock(&mgr->lock);
4850 
4851 }
4852 EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4853 
drm_dp_tx_work(struct work_struct * work)4854 static void drm_dp_tx_work(struct work_struct *work)
4855 {
4856 	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4857 
4858 	mutex_lock(&mgr->qlock);
4859 	if (!list_empty(&mgr->tx_msg_downq))
4860 		process_single_down_tx_qlock(mgr);
4861 	mutex_unlock(&mgr->qlock);
4862 }
4863 
4864 static inline void
drm_dp_delayed_destroy_port(struct drm_dp_mst_port * port)4865 drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4866 {
4867 	drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4868 
4869 	if (port->connector) {
4870 		drm_connector_unregister(port->connector);
4871 		drm_connector_put(port->connector);
4872 	}
4873 
4874 	drm_dp_mst_put_port_malloc(port);
4875 }
4876 
4877 static inline void
drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch * mstb)4878 drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4879 {
4880 	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4881 	struct drm_dp_mst_port *port, *port_tmp;
4882 	struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4883 	bool wake_tx = false;
4884 
4885 	mutex_lock(&mgr->lock);
4886 	list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4887 		list_del(&port->next);
4888 		drm_dp_mst_topology_put_port(port);
4889 	}
4890 	mutex_unlock(&mgr->lock);
4891 
4892 	/* drop any tx slot msg */
4893 	mutex_lock(&mstb->mgr->qlock);
4894 	list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4895 		if (txmsg->dst != mstb)
4896 			continue;
4897 
4898 		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4899 		list_del(&txmsg->next);
4900 		wake_tx = true;
4901 	}
4902 	mutex_unlock(&mstb->mgr->qlock);
4903 
4904 	if (wake_tx)
4905 		wake_up_all(&mstb->mgr->tx_waitq);
4906 
4907 	drm_dp_mst_put_mstb_malloc(mstb);
4908 }
4909 
drm_dp_delayed_destroy_work(struct work_struct * work)4910 static void drm_dp_delayed_destroy_work(struct work_struct *work)
4911 {
4912 	struct drm_dp_mst_topology_mgr *mgr =
4913 		container_of(work, struct drm_dp_mst_topology_mgr,
4914 			     delayed_destroy_work);
4915 	bool send_hotplug = false, go_again;
4916 
4917 	/*
4918 	 * Not a regular list traverse as we have to drop the destroy
4919 	 * connector lock before destroying the mstb/port, to avoid AB->BA
4920 	 * ordering between this lock and the config mutex.
4921 	 */
4922 	do {
4923 		go_again = false;
4924 
4925 		for (;;) {
4926 			struct drm_dp_mst_branch *mstb;
4927 
4928 			mutex_lock(&mgr->delayed_destroy_lock);
4929 			mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
4930 							struct drm_dp_mst_branch,
4931 							destroy_next);
4932 			if (mstb)
4933 				list_del(&mstb->destroy_next);
4934 			mutex_unlock(&mgr->delayed_destroy_lock);
4935 
4936 			if (!mstb)
4937 				break;
4938 
4939 			drm_dp_delayed_destroy_mstb(mstb);
4940 			go_again = true;
4941 		}
4942 
4943 		for (;;) {
4944 			struct drm_dp_mst_port *port;
4945 
4946 			mutex_lock(&mgr->delayed_destroy_lock);
4947 			port = list_first_entry_or_null(&mgr->destroy_port_list,
4948 							struct drm_dp_mst_port,
4949 							next);
4950 			if (port)
4951 				list_del(&port->next);
4952 			mutex_unlock(&mgr->delayed_destroy_lock);
4953 
4954 			if (!port)
4955 				break;
4956 
4957 			drm_dp_delayed_destroy_port(port);
4958 			send_hotplug = true;
4959 			go_again = true;
4960 		}
4961 	} while (go_again);
4962 
4963 	if (send_hotplug)
4964 		drm_kms_helper_hotplug_event(mgr->dev);
4965 }
4966 
4967 static struct drm_private_state *
drm_dp_mst_duplicate_state(struct drm_private_obj * obj)4968 drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
4969 {
4970 	struct drm_dp_mst_topology_state *state, *old_state =
4971 		to_dp_mst_topology_state(obj->state);
4972 	struct drm_dp_vcpi_allocation *pos, *vcpi;
4973 
4974 	state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
4975 	if (!state)
4976 		return NULL;
4977 
4978 	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
4979 
4980 	INIT_LIST_HEAD(&state->vcpis);
4981 
4982 	list_for_each_entry(pos, &old_state->vcpis, next) {
4983 		/* Prune leftover freed VCPI allocations */
4984 		if (!pos->vcpi)
4985 			continue;
4986 
4987 		vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
4988 		if (!vcpi)
4989 			goto fail;
4990 
4991 		drm_dp_mst_get_port_malloc(vcpi->port);
4992 		list_add(&vcpi->next, &state->vcpis);
4993 	}
4994 
4995 	return &state->base;
4996 
4997 fail:
4998 	list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
4999 		drm_dp_mst_put_port_malloc(pos->port);
5000 		kfree(pos);
5001 	}
5002 	kfree(state);
5003 
5004 	return NULL;
5005 }
5006 
drm_dp_mst_destroy_state(struct drm_private_obj * obj,struct drm_private_state * state)5007 static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5008 				     struct drm_private_state *state)
5009 {
5010 	struct drm_dp_mst_topology_state *mst_state =
5011 		to_dp_mst_topology_state(state);
5012 	struct drm_dp_vcpi_allocation *pos, *tmp;
5013 
5014 	list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
5015 		/* We only keep references to ports with non-zero VCPIs */
5016 		if (pos->vcpi)
5017 			drm_dp_mst_put_port_malloc(pos->port);
5018 		kfree(pos);
5019 	}
5020 
5021 	kfree(mst_state);
5022 }
5023 
drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port * port,struct drm_dp_mst_branch * branch)5024 static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5025 						 struct drm_dp_mst_branch *branch)
5026 {
5027 	while (port->parent) {
5028 		if (port->parent == branch)
5029 			return true;
5030 
5031 		if (port->parent->port_parent)
5032 			port = port->parent->port_parent;
5033 		else
5034 			break;
5035 	}
5036 	return false;
5037 }
5038 
5039 static int
5040 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5041 				      struct drm_dp_mst_topology_state *state);
5042 
5043 static int
drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_topology_state * state)5044 drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5045 				      struct drm_dp_mst_topology_state *state)
5046 {
5047 	struct drm_dp_vcpi_allocation *vcpi;
5048 	struct drm_dp_mst_port *port;
5049 	int pbn_used = 0, ret;
5050 	bool found = false;
5051 
5052 	/* Check that we have at least one port in our state that's downstream
5053 	 * of this branch, otherwise we can skip this branch
5054 	 */
5055 	list_for_each_entry(vcpi, &state->vcpis, next) {
5056 		if (!vcpi->pbn ||
5057 		    !drm_dp_mst_port_downstream_of_branch(vcpi->port, mstb))
5058 			continue;
5059 
5060 		found = true;
5061 		break;
5062 	}
5063 	if (!found)
5064 		return 0;
5065 
5066 	if (mstb->port_parent)
5067 		DRM_DEBUG_ATOMIC("[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5068 				 mstb->port_parent->parent, mstb->port_parent,
5069 				 mstb);
5070 	else
5071 		DRM_DEBUG_ATOMIC("[MSTB:%p] Checking bandwidth limits\n",
5072 				 mstb);
5073 
5074 	list_for_each_entry(port, &mstb->ports, next) {
5075 		ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
5076 		if (ret < 0)
5077 			return ret;
5078 
5079 		pbn_used += ret;
5080 	}
5081 
5082 	return pbn_used;
5083 }
5084 
5085 static int
drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port * port,struct drm_dp_mst_topology_state * state)5086 drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5087 				      struct drm_dp_mst_topology_state *state)
5088 {
5089 	struct drm_dp_vcpi_allocation *vcpi;
5090 	int pbn_used = 0;
5091 
5092 	if (port->pdt == DP_PEER_DEVICE_NONE)
5093 		return 0;
5094 
5095 	if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5096 		bool found = false;
5097 
5098 		list_for_each_entry(vcpi, &state->vcpis, next) {
5099 			if (vcpi->port != port)
5100 				continue;
5101 			if (!vcpi->pbn)
5102 				return 0;
5103 
5104 			found = true;
5105 			break;
5106 		}
5107 		if (!found)
5108 			return 0;
5109 
5110 		/* This should never happen, as it means we tried to
5111 		 * set a mode before querying the full_pbn
5112 		 */
5113 		if (WARN_ON(!port->full_pbn))
5114 			return -EINVAL;
5115 
5116 		pbn_used = vcpi->pbn;
5117 	} else {
5118 		pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5119 								 state);
5120 		if (pbn_used <= 0)
5121 			return pbn_used;
5122 	}
5123 
5124 	if (pbn_used > port->full_pbn) {
5125 		DRM_DEBUG_ATOMIC("[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5126 				 port->parent, port, pbn_used,
5127 				 port->full_pbn);
5128 		return -ENOSPC;
5129 	}
5130 
5131 	DRM_DEBUG_ATOMIC("[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5132 			 port->parent, port, pbn_used, port->full_pbn);
5133 
5134 	return pbn_used;
5135 }
5136 
5137 static inline int
drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr * mgr,struct drm_dp_mst_topology_state * mst_state)5138 drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
5139 					 struct drm_dp_mst_topology_state *mst_state)
5140 {
5141 	struct drm_dp_vcpi_allocation *vcpi;
5142 	int avail_slots = 63, payload_count = 0;
5143 
5144 	list_for_each_entry(vcpi, &mst_state->vcpis, next) {
5145 		/* Releasing VCPI is always OK-even if the port is gone */
5146 		if (!vcpi->vcpi) {
5147 			DRM_DEBUG_ATOMIC("[MST PORT:%p] releases all VCPI slots\n",
5148 					 vcpi->port);
5149 			continue;
5150 		}
5151 
5152 		DRM_DEBUG_ATOMIC("[MST PORT:%p] requires %d vcpi slots\n",
5153 				 vcpi->port, vcpi->vcpi);
5154 
5155 		avail_slots -= vcpi->vcpi;
5156 		if (avail_slots < 0) {
5157 			DRM_DEBUG_ATOMIC("[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
5158 					 vcpi->port, mst_state,
5159 					 avail_slots + vcpi->vcpi);
5160 			return -ENOSPC;
5161 		}
5162 
5163 		if (++payload_count > mgr->max_payloads) {
5164 			DRM_DEBUG_ATOMIC("[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5165 					 mgr, mst_state, mgr->max_payloads);
5166 			return -EINVAL;
5167 		}
5168 	}
5169 	DRM_DEBUG_ATOMIC("[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
5170 			 mgr, mst_state, avail_slots,
5171 			 63 - avail_slots);
5172 
5173 	return 0;
5174 }
5175 
5176 /**
5177  * drm_dp_mst_add_affected_dsc_crtcs
5178  * @state: Pointer to the new struct drm_dp_mst_topology_state
5179  * @mgr: MST topology manager
5180  *
5181  * Whenever there is a change in mst topology
5182  * DSC configuration would have to be recalculated
5183  * therefore we need to trigger modeset on all affected
5184  * CRTCs in that topology
5185  *
5186  * See also:
5187  * drm_dp_mst_atomic_enable_dsc()
5188  */
drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr)5189 int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5190 {
5191 	struct drm_dp_mst_topology_state *mst_state;
5192 	struct drm_dp_vcpi_allocation *pos;
5193 	struct drm_connector *connector;
5194 	struct drm_connector_state *conn_state;
5195 	struct drm_crtc *crtc;
5196 	struct drm_crtc_state *crtc_state;
5197 
5198 	mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5199 
5200 	if (IS_ERR(mst_state))
5201 		return -EINVAL;
5202 
5203 	list_for_each_entry(pos, &mst_state->vcpis, next) {
5204 
5205 		connector = pos->port->connector;
5206 
5207 		if (!connector)
5208 			return -EINVAL;
5209 
5210 		conn_state = drm_atomic_get_connector_state(state, connector);
5211 
5212 		if (IS_ERR(conn_state))
5213 			return PTR_ERR(conn_state);
5214 
5215 		crtc = conn_state->crtc;
5216 
5217 		if (!crtc)
5218 			continue;
5219 
5220 		if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5221 			continue;
5222 
5223 		crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5224 
5225 		if (IS_ERR(crtc_state))
5226 			return PTR_ERR(crtc_state);
5227 
5228 		DRM_DEBUG_ATOMIC("[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5229 				 mgr, crtc);
5230 
5231 		crtc_state->mode_changed = true;
5232 	}
5233 	return 0;
5234 }
5235 EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5236 
5237 /**
5238  * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5239  * @state: Pointer to the new drm_atomic_state
5240  * @port: Pointer to the affected MST Port
5241  * @pbn: Newly recalculated bw required for link with DSC enabled
5242  * @pbn_div: Divider to calculate correct number of pbn per slot
5243  * @enable: Boolean flag to enable or disable DSC on the port
5244  *
5245  * This function enables DSC on the given Port
5246  * by recalculating its vcpi from pbn provided
5247  * and sets dsc_enable flag to keep track of which
5248  * ports have DSC enabled
5249  *
5250  */
drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state * state,struct drm_dp_mst_port * port,int pbn,int pbn_div,bool enable)5251 int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5252 				 struct drm_dp_mst_port *port,
5253 				 int pbn, int pbn_div,
5254 				 bool enable)
5255 {
5256 	struct drm_dp_mst_topology_state *mst_state;
5257 	struct drm_dp_vcpi_allocation *pos;
5258 	bool found = false;
5259 	int vcpi = 0;
5260 
5261 	mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5262 
5263 	if (IS_ERR(mst_state))
5264 		return PTR_ERR(mst_state);
5265 
5266 	list_for_each_entry(pos, &mst_state->vcpis, next) {
5267 		if (pos->port == port) {
5268 			found = true;
5269 			break;
5270 		}
5271 	}
5272 
5273 	if (!found) {
5274 		DRM_DEBUG_ATOMIC("[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
5275 				 port, mst_state);
5276 		return -EINVAL;
5277 	}
5278 
5279 	if (pos->dsc_enabled == enable) {
5280 		DRM_DEBUG_ATOMIC("[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
5281 				 port, enable, pos->vcpi);
5282 		vcpi = pos->vcpi;
5283 	}
5284 
5285 	if (enable) {
5286 		vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
5287 		DRM_DEBUG_ATOMIC("[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
5288 				 port, vcpi);
5289 		if (vcpi < 0)
5290 			return -EINVAL;
5291 	}
5292 
5293 	pos->dsc_enabled = enable;
5294 
5295 	return vcpi;
5296 }
5297 EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5298 /**
5299  * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5300  * atomic update is valid
5301  * @state: Pointer to the new &struct drm_dp_mst_topology_state
5302  *
5303  * Checks the given topology state for an atomic update to ensure that it's
5304  * valid. This includes checking whether there's enough bandwidth to support
5305  * the new VCPI allocations in the atomic update.
5306  *
5307  * Any atomic drivers supporting DP MST must make sure to call this after
5308  * checking the rest of their state in their
5309  * &drm_mode_config_funcs.atomic_check() callback.
5310  *
5311  * See also:
5312  * drm_dp_atomic_find_vcpi_slots()
5313  * drm_dp_atomic_release_vcpi_slots()
5314  *
5315  * Returns:
5316  *
5317  * 0 if the new state is valid, negative error code otherwise.
5318  */
drm_dp_mst_atomic_check(struct drm_atomic_state * state)5319 int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5320 {
5321 	struct drm_dp_mst_topology_mgr *mgr;
5322 	struct drm_dp_mst_topology_state *mst_state;
5323 	int i, ret = 0;
5324 
5325 	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5326 		if (!mgr->mst_state)
5327 			continue;
5328 
5329 		ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state);
5330 		if (ret)
5331 			break;
5332 
5333 		mutex_lock(&mgr->lock);
5334 		ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5335 							    mst_state);
5336 		mutex_unlock(&mgr->lock);
5337 		if (ret < 0)
5338 			break;
5339 		else
5340 			ret = 0;
5341 	}
5342 
5343 	return ret;
5344 }
5345 EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5346 
5347 const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5348 	.atomic_duplicate_state = drm_dp_mst_duplicate_state,
5349 	.atomic_destroy_state = drm_dp_mst_destroy_state,
5350 };
5351 EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5352 
5353 /**
5354  * drm_atomic_get_mst_topology_state: get MST topology state
5355  *
5356  * @state: global atomic state
5357  * @mgr: MST topology manager, also the private object in this case
5358  *
5359  * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5360  * state vtable so that the private object state returned is that of a MST
5361  * topology object. Also, drm_atomic_get_private_obj_state() expects the caller
5362  * to care of the locking, so warn if don't hold the connection_mutex.
5363  *
5364  * RETURNS:
5365  *
5366  * The MST topology state or error pointer.
5367  */
drm_atomic_get_mst_topology_state(struct drm_atomic_state * state,struct drm_dp_mst_topology_mgr * mgr)5368 struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5369 								    struct drm_dp_mst_topology_mgr *mgr)
5370 {
5371 	return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5372 }
5373 EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5374 
5375 /**
5376  * drm_dp_mst_topology_mgr_init - initialise a topology manager
5377  * @mgr: manager struct to initialise
5378  * @dev: device providing this structure - for i2c addition.
5379  * @aux: DP helper aux channel to talk to this device
5380  * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5381  * @max_payloads: maximum number of payloads this GPU can source
5382  * @conn_base_id: the connector object ID the MST device is connected to.
5383  *
5384  * Return 0 for success, or negative error code on failure
5385  */
drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr * mgr,struct drm_device * dev,struct drm_dp_aux * aux,int max_dpcd_transaction_bytes,int max_payloads,int conn_base_id)5386 int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5387 				 struct drm_device *dev, struct drm_dp_aux *aux,
5388 				 int max_dpcd_transaction_bytes,
5389 				 int max_payloads, int conn_base_id)
5390 {
5391 	struct drm_dp_mst_topology_state *mst_state;
5392 
5393 	mutex_init(&mgr->lock);
5394 	mutex_init(&mgr->qlock);
5395 	mutex_init(&mgr->payload_lock);
5396 	mutex_init(&mgr->delayed_destroy_lock);
5397 	mutex_init(&mgr->up_req_lock);
5398 	mutex_init(&mgr->probe_lock);
5399 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5400 	mutex_init(&mgr->topology_ref_history_lock);
5401 #endif
5402 	INIT_LIST_HEAD(&mgr->tx_msg_downq);
5403 	INIT_LIST_HEAD(&mgr->destroy_port_list);
5404 	INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5405 	INIT_LIST_HEAD(&mgr->up_req_list);
5406 
5407 	/*
5408 	 * delayed_destroy_work will be queued on a dedicated WQ, so that any
5409 	 * requeuing will be also flushed when deiniting the topology manager.
5410 	 */
5411 	mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5412 	if (mgr->delayed_destroy_wq == NULL)
5413 		return -ENOMEM;
5414 
5415 	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5416 	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5417 	INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5418 	INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5419 	init_waitqueue_head(&mgr->tx_waitq);
5420 	mgr->dev = dev;
5421 	mgr->aux = aux;
5422 	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5423 	mgr->max_payloads = max_payloads;
5424 	mgr->conn_base_id = conn_base_id;
5425 	if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
5426 	    max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
5427 		return -EINVAL;
5428 	mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
5429 	if (!mgr->payloads)
5430 		return -ENOMEM;
5431 	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
5432 	if (!mgr->proposed_vcpis)
5433 		return -ENOMEM;
5434 	set_bit(0, &mgr->payload_mask);
5435 
5436 	mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5437 	if (mst_state == NULL)
5438 		return -ENOMEM;
5439 
5440 	mst_state->mgr = mgr;
5441 	INIT_LIST_HEAD(&mst_state->vcpis);
5442 
5443 	drm_atomic_private_obj_init(dev, &mgr->base,
5444 				    &mst_state->base,
5445 				    &drm_dp_mst_topology_state_funcs);
5446 
5447 	return 0;
5448 }
5449 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5450 
5451 /**
5452  * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5453  * @mgr: manager to destroy
5454  */
drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr * mgr)5455 void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5456 {
5457 	drm_dp_mst_topology_mgr_set_mst(mgr, false);
5458 	flush_work(&mgr->work);
5459 	/* The following will also drain any requeued work on the WQ. */
5460 	if (mgr->delayed_destroy_wq) {
5461 		destroy_workqueue(mgr->delayed_destroy_wq);
5462 		mgr->delayed_destroy_wq = NULL;
5463 	}
5464 	mutex_lock(&mgr->payload_lock);
5465 	kfree(mgr->payloads);
5466 	mgr->payloads = NULL;
5467 	kfree(mgr->proposed_vcpis);
5468 	mgr->proposed_vcpis = NULL;
5469 	mutex_unlock(&mgr->payload_lock);
5470 	mgr->dev = NULL;
5471 	mgr->aux = NULL;
5472 	drm_atomic_private_obj_fini(&mgr->base);
5473 	mgr->funcs = NULL;
5474 
5475 	mutex_destroy(&mgr->delayed_destroy_lock);
5476 	mutex_destroy(&mgr->payload_lock);
5477 	mutex_destroy(&mgr->qlock);
5478 	mutex_destroy(&mgr->lock);
5479 	mutex_destroy(&mgr->up_req_lock);
5480 	mutex_destroy(&mgr->probe_lock);
5481 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5482 	mutex_destroy(&mgr->topology_ref_history_lock);
5483 #endif
5484 }
5485 EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5486 
remote_i2c_read_ok(const struct i2c_msg msgs[],int num)5487 static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5488 {
5489 	int i;
5490 
5491 	if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5492 		return false;
5493 
5494 	for (i = 0; i < num - 1; i++) {
5495 		if (msgs[i].flags & I2C_M_RD ||
5496 		    msgs[i].len > 0xff)
5497 			return false;
5498 	}
5499 
5500 	return msgs[num - 1].flags & I2C_M_RD &&
5501 		msgs[num - 1].len <= 0xff;
5502 }
5503 
remote_i2c_write_ok(const struct i2c_msg msgs[],int num)5504 static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5505 {
5506 	int i;
5507 
5508 	for (i = 0; i < num - 1; i++) {
5509 		if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5510 		    msgs[i].len > 0xff)
5511 			return false;
5512 	}
5513 
5514 	return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5515 }
5516 
drm_dp_mst_i2c_read(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port,struct i2c_msg * msgs,int num)5517 static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5518 			       struct drm_dp_mst_port *port,
5519 			       struct i2c_msg *msgs, int num)
5520 {
5521 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5522 	unsigned int i;
5523 	struct drm_dp_sideband_msg_req_body msg;
5524 	struct drm_dp_sideband_msg_tx *txmsg = NULL;
5525 	int ret;
5526 
5527 	memset(&msg, 0, sizeof(msg));
5528 	msg.req_type = DP_REMOTE_I2C_READ;
5529 	msg.u.i2c_read.num_transactions = num - 1;
5530 	msg.u.i2c_read.port_number = port->port_num;
5531 	for (i = 0; i < num - 1; i++) {
5532 		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5533 		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5534 		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5535 		msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5536 	}
5537 	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5538 	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5539 
5540 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5541 	if (!txmsg) {
5542 		ret = -ENOMEM;
5543 		goto out;
5544 	}
5545 
5546 	txmsg->dst = mstb;
5547 	drm_dp_encode_sideband_req(&msg, txmsg);
5548 
5549 	drm_dp_queue_down_tx(mgr, txmsg);
5550 
5551 	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5552 	if (ret > 0) {
5553 
5554 		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5555 			ret = -EREMOTEIO;
5556 			goto out;
5557 		}
5558 		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5559 			ret = -EIO;
5560 			goto out;
5561 		}
5562 		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5563 		ret = num;
5564 	}
5565 out:
5566 	kfree(txmsg);
5567 	return ret;
5568 }
5569 
drm_dp_mst_i2c_write(struct drm_dp_mst_branch * mstb,struct drm_dp_mst_port * port,struct i2c_msg * msgs,int num)5570 static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5571 				struct drm_dp_mst_port *port,
5572 				struct i2c_msg *msgs, int num)
5573 {
5574 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5575 	unsigned int i;
5576 	struct drm_dp_sideband_msg_req_body msg;
5577 	struct drm_dp_sideband_msg_tx *txmsg = NULL;
5578 	int ret;
5579 
5580 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5581 	if (!txmsg) {
5582 		ret = -ENOMEM;
5583 		goto out;
5584 	}
5585 	for (i = 0; i < num; i++) {
5586 		memset(&msg, 0, sizeof(msg));
5587 		msg.req_type = DP_REMOTE_I2C_WRITE;
5588 		msg.u.i2c_write.port_number = port->port_num;
5589 		msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5590 		msg.u.i2c_write.num_bytes = msgs[i].len;
5591 		msg.u.i2c_write.bytes = msgs[i].buf;
5592 
5593 		memset(txmsg, 0, sizeof(*txmsg));
5594 		txmsg->dst = mstb;
5595 
5596 		drm_dp_encode_sideband_req(&msg, txmsg);
5597 		drm_dp_queue_down_tx(mgr, txmsg);
5598 
5599 		ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5600 		if (ret > 0) {
5601 			if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5602 				ret = -EREMOTEIO;
5603 				goto out;
5604 			}
5605 		} else {
5606 			goto out;
5607 		}
5608 	}
5609 	ret = num;
5610 out:
5611 	kfree(txmsg);
5612 	return ret;
5613 }
5614 
5615 /* I2C device */
drm_dp_mst_i2c_xfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int num)5616 static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5617 			       struct i2c_msg *msgs, int num)
5618 {
5619 	struct drm_dp_aux *aux = adapter->algo_data;
5620 	struct drm_dp_mst_port *port =
5621 		container_of(aux, struct drm_dp_mst_port, aux);
5622 	struct drm_dp_mst_branch *mstb;
5623 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5624 	int ret;
5625 
5626 	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5627 	if (!mstb)
5628 		return -EREMOTEIO;
5629 
5630 	if (remote_i2c_read_ok(msgs, num)) {
5631 		ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5632 	} else if (remote_i2c_write_ok(msgs, num)) {
5633 		ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5634 	} else {
5635 		DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
5636 		ret = -EIO;
5637 	}
5638 
5639 	drm_dp_mst_topology_put_mstb(mstb);
5640 	return ret;
5641 }
5642 
drm_dp_mst_i2c_functionality(struct i2c_adapter * adapter)5643 static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5644 {
5645 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5646 	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5647 	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5648 	       I2C_FUNC_10BIT_ADDR;
5649 }
5650 
5651 static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5652 	.functionality = drm_dp_mst_i2c_functionality,
5653 	.master_xfer = drm_dp_mst_i2c_xfer,
5654 };
5655 
5656 /**
5657  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5658  * @port: The port to add the I2C bus on
5659  *
5660  * Returns 0 on success or a negative error code on failure.
5661  */
drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port * port)5662 static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5663 {
5664 	struct drm_dp_aux *aux = &port->aux;
5665 	struct device *parent_dev = port->mgr->dev->dev;
5666 
5667 	aux->ddc.algo = &drm_dp_mst_i2c_algo;
5668 	aux->ddc.algo_data = aux;
5669 	aux->ddc.retries = 3;
5670 
5671 	aux->ddc.class = I2C_CLASS_DDC;
5672 	aux->ddc.owner = THIS_MODULE;
5673 	/* FIXME: set the kdev of the port's connector as parent */
5674 	aux->ddc.dev.parent = parent_dev;
5675 	aux->ddc.dev.of_node = parent_dev->of_node;
5676 
5677 	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5678 		sizeof(aux->ddc.name));
5679 
5680 	return i2c_add_adapter(&aux->ddc);
5681 }
5682 
5683 /**
5684  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5685  * @port: The port to remove the I2C bus from
5686  */
drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port * port)5687 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5688 {
5689 	i2c_del_adapter(&port->aux.ddc);
5690 }
5691 
5692 /**
5693  * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5694  * @port: The port to check
5695  *
5696  * A single physical MST hub object can be represented in the topology
5697  * by multiple branches, with virtual ports between those branches.
5698  *
5699  * As of DP1.4, An MST hub with internal (virtual) ports must expose
5700  * certain DPCD registers over those ports. See sections 2.6.1.1.1
5701  * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5702  *
5703  * May acquire mgr->lock
5704  *
5705  * Returns:
5706  * true if the port is a virtual DP peer device, false otherwise
5707  */
drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port * port)5708 static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5709 {
5710 	struct drm_dp_mst_port *downstream_port;
5711 
5712 	if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5713 		return false;
5714 
5715 	/* Virtual DP Sink (Internal Display Panel) */
5716 	if (port->port_num >= 8)
5717 		return true;
5718 
5719 	/* DP-to-HDMI Protocol Converter */
5720 	if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5721 	    !port->mcs &&
5722 	    port->ldps)
5723 		return true;
5724 
5725 	/* DP-to-DP */
5726 	mutex_lock(&port->mgr->lock);
5727 	if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5728 	    port->mstb &&
5729 	    port->mstb->num_ports == 2) {
5730 		list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5731 			if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5732 			    !downstream_port->input) {
5733 				mutex_unlock(&port->mgr->lock);
5734 				return true;
5735 			}
5736 		}
5737 	}
5738 	mutex_unlock(&port->mgr->lock);
5739 
5740 	return false;
5741 }
5742 
5743 /**
5744  * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5745  * @port: The port to check. A leaf of the MST tree with an attached display.
5746  *
5747  * Depending on the situation, DSC may be enabled via the endpoint aux,
5748  * the immediately upstream aux, or the connector's physical aux.
5749  *
5750  * This is both the correct aux to read DSC_CAPABILITY and the
5751  * correct aux to write DSC_ENABLED.
5752  *
5753  * This operation can be expensive (up to four aux reads), so
5754  * the caller should cache the return.
5755  *
5756  * Returns:
5757  * NULL if DSC cannot be enabled on this port, otherwise the aux device
5758  */
drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port * port)5759 struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5760 {
5761 	struct drm_dp_mst_port *immediate_upstream_port;
5762 	struct drm_dp_mst_port *fec_port;
5763 	struct drm_dp_desc desc = {};
5764 	u8 endpoint_fec;
5765 	u8 endpoint_dsc;
5766 
5767 	if (!port)
5768 		return NULL;
5769 
5770 	if (port->parent->port_parent)
5771 		immediate_upstream_port = port->parent->port_parent;
5772 	else
5773 		immediate_upstream_port = NULL;
5774 
5775 	fec_port = immediate_upstream_port;
5776 	while (fec_port) {
5777 		/*
5778 		 * Each physical link (i.e. not a virtual port) between the
5779 		 * output and the primary device must support FEC
5780 		 */
5781 		if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5782 		    !fec_port->fec_capable)
5783 			return NULL;
5784 
5785 		fec_port = fec_port->parent->port_parent;
5786 	}
5787 
5788 	/* DP-to-DP peer device */
5789 	if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5790 		u8 upstream_dsc;
5791 
5792 		if (drm_dp_dpcd_read(&port->aux,
5793 				     DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5794 			return NULL;
5795 		if (drm_dp_dpcd_read(&port->aux,
5796 				     DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5797 			return NULL;
5798 		if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5799 				     DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5800 			return NULL;
5801 
5802 		/* Enpoint decompression with DP-to-DP peer device */
5803 		if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5804 		    (endpoint_fec & DP_FEC_CAPABLE) &&
5805 		    (upstream_dsc & 0x2) /* DSC passthrough */)
5806 			return &port->aux;
5807 
5808 		/* Virtual DPCD decompression with DP-to-DP peer device */
5809 		return &immediate_upstream_port->aux;
5810 	}
5811 
5812 	/* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5813 	if (drm_dp_mst_is_virtual_dpcd(port))
5814 		return &port->aux;
5815 
5816 	/*
5817 	 * Synaptics quirk
5818 	 * Applies to ports for which:
5819 	 * - Physical aux has Synaptics OUI
5820 	 * - DPv1.4 or higher
5821 	 * - Port is on primary branch device
5822 	 * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5823 	 */
5824 	if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5825 		return NULL;
5826 
5827 	if (drm_dp_has_quirk(&desc, 0,
5828 			     DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5829 	    port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5830 	    port->parent == port->mgr->mst_primary) {
5831 		u8 downstreamport;
5832 
5833 		if (drm_dp_dpcd_read(&port->aux, DP_DOWNSTREAMPORT_PRESENT,
5834 				     &downstreamport, 1) < 0)
5835 			return NULL;
5836 
5837 		if ((downstreamport & DP_DWN_STRM_PORT_PRESENT) &&
5838 		   ((downstreamport & DP_DWN_STRM_PORT_TYPE_MASK)
5839 		     != DP_DWN_STRM_PORT_TYPE_ANALOG))
5840 			return port->mgr->aux;
5841 	}
5842 
5843 	/*
5844 	 * The check below verifies if the MST sink
5845 	 * connected to the GPU is capable of DSC -
5846 	 * therefore the endpoint needs to be
5847 	 * both DSC and FEC capable.
5848 	 */
5849 	if (drm_dp_dpcd_read(&port->aux,
5850 	   DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5851 		return NULL;
5852 	if (drm_dp_dpcd_read(&port->aux,
5853 	   DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5854 		return NULL;
5855 	if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5856 	   (endpoint_fec & DP_FEC_CAPABLE))
5857 		return &port->aux;
5858 
5859 	return NULL;
5860 }
5861 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);
5862