1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Function Control Protocol (IEC 61883-1) helper functions
4 *
5 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
6 */
7
8 #include <linux/device.h>
9 #include <linux/firewire.h>
10 #include <linux/firewire-constants.h>
11 #include <linux/list.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/sched.h>
15 #include <linux/spinlock.h>
16 #include <linux/wait.h>
17 #include <linux/delay.h>
18 #include "fcp.h"
19 #include "lib.h"
20 #include "amdtp-stream.h"
21
22 #define CTS_AVC 0x00
23
24 #define ERROR_RETRIES 3
25 #define ERROR_DELAY_MS 5
26 #define FCP_TIMEOUT_MS 125
27
avc_general_set_sig_fmt(struct fw_unit * unit,unsigned int rate,enum avc_general_plug_dir dir,unsigned short pid)28 int avc_general_set_sig_fmt(struct fw_unit *unit, unsigned int rate,
29 enum avc_general_plug_dir dir,
30 unsigned short pid)
31 {
32 unsigned int sfc;
33 u8 *buf;
34 bool flag;
35 int err;
36
37 flag = false;
38 for (sfc = 0; sfc < CIP_SFC_COUNT; sfc++) {
39 if (amdtp_rate_table[sfc] == rate) {
40 flag = true;
41 break;
42 }
43 }
44 if (!flag)
45 return -EINVAL;
46
47 buf = kzalloc(8, GFP_KERNEL);
48 if (buf == NULL)
49 return -ENOMEM;
50
51 buf[0] = 0x00; /* AV/C CONTROL */
52 buf[1] = 0xff; /* UNIT */
53 if (dir == AVC_GENERAL_PLUG_DIR_IN)
54 buf[2] = 0x19; /* INPUT PLUG SIGNAL FORMAT */
55 else
56 buf[2] = 0x18; /* OUTPUT PLUG SIGNAL FORMAT */
57 buf[3] = 0xff & pid; /* plug id */
58 buf[4] = 0x90; /* EOH_1, Form_1, FMT. AM824 */
59 buf[5] = 0x07 & sfc; /* FDF-hi. AM824, frequency */
60 buf[6] = 0xff; /* FDF-mid. AM824, SYT hi (not used)*/
61 buf[7] = 0xff; /* FDF-low. AM824, SYT lo (not used) */
62
63 /* do transaction and check buf[1-5] are the same against command */
64 err = fcp_avc_transaction(unit, buf, 8, buf, 8,
65 BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5));
66 if (err < 0)
67 ;
68 else if (err < 8)
69 err = -EIO;
70 else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
71 err = -ENOSYS;
72 else if (buf[0] == 0x0a) /* REJECTED */
73 err = -EINVAL;
74 if (err < 0)
75 goto end;
76
77 err = 0;
78 end:
79 kfree(buf);
80 return err;
81 }
82 EXPORT_SYMBOL(avc_general_set_sig_fmt);
83
avc_general_get_sig_fmt(struct fw_unit * unit,unsigned int * rate,enum avc_general_plug_dir dir,unsigned short pid)84 int avc_general_get_sig_fmt(struct fw_unit *unit, unsigned int *rate,
85 enum avc_general_plug_dir dir,
86 unsigned short pid)
87 {
88 unsigned int sfc;
89 u8 *buf;
90 int err;
91
92 buf = kzalloc(8, GFP_KERNEL);
93 if (buf == NULL)
94 return -ENOMEM;
95
96 buf[0] = 0x01; /* AV/C STATUS */
97 buf[1] = 0xff; /* Unit */
98 if (dir == AVC_GENERAL_PLUG_DIR_IN)
99 buf[2] = 0x19; /* INPUT PLUG SIGNAL FORMAT */
100 else
101 buf[2] = 0x18; /* OUTPUT PLUG SIGNAL FORMAT */
102 buf[3] = 0xff & pid; /* plug id */
103 buf[4] = 0x90; /* EOH_1, Form_1, FMT. AM824 */
104 buf[5] = 0xff; /* FDF-hi. AM824, frequency */
105 buf[6] = 0xff; /* FDF-mid. AM824, SYT hi (not used) */
106 buf[7] = 0xff; /* FDF-low. AM824, SYT lo (not used) */
107
108 /* do transaction and check buf[1-4] are the same against command */
109 err = fcp_avc_transaction(unit, buf, 8, buf, 8,
110 BIT(1) | BIT(2) | BIT(3) | BIT(4));
111 if (err < 0)
112 ;
113 else if (err < 8)
114 err = -EIO;
115 else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
116 err = -ENOSYS;
117 else if (buf[0] == 0x0a) /* REJECTED */
118 err = -EINVAL;
119 else if (buf[0] == 0x0b) /* IN TRANSITION */
120 err = -EAGAIN;
121 if (err < 0)
122 goto end;
123
124 /* check sfc field and pick up rate */
125 sfc = 0x07 & buf[5];
126 if (sfc >= CIP_SFC_COUNT) {
127 err = -EAGAIN; /* also in transition */
128 goto end;
129 }
130
131 *rate = amdtp_rate_table[sfc];
132 err = 0;
133 end:
134 kfree(buf);
135 return err;
136 }
137 EXPORT_SYMBOL(avc_general_get_sig_fmt);
138
avc_general_get_plug_info(struct fw_unit * unit,unsigned int subunit_type,unsigned int subunit_id,unsigned int subfunction,u8 info[AVC_PLUG_INFO_BUF_BYTES])139 int avc_general_get_plug_info(struct fw_unit *unit, unsigned int subunit_type,
140 unsigned int subunit_id, unsigned int subfunction,
141 u8 info[AVC_PLUG_INFO_BUF_BYTES])
142 {
143 u8 *buf;
144 int err;
145
146 /* extended subunit in spec.4.2 is not supported */
147 if ((subunit_type == 0x1E) || (subunit_id == 5))
148 return -EINVAL;
149
150 buf = kzalloc(8, GFP_KERNEL);
151 if (buf == NULL)
152 return -ENOMEM;
153
154 buf[0] = 0x01; /* AV/C STATUS */
155 /* UNIT or Subunit, Functionblock */
156 buf[1] = ((subunit_type & 0x1f) << 3) | (subunit_id & 0x7);
157 buf[2] = 0x02; /* PLUG INFO */
158 buf[3] = 0xff & subfunction;
159
160 err = fcp_avc_transaction(unit, buf, 8, buf, 8, BIT(1) | BIT(2));
161 if (err < 0)
162 ;
163 else if (err < 8)
164 err = -EIO;
165 else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
166 err = -ENOSYS;
167 else if (buf[0] == 0x0a) /* REJECTED */
168 err = -EINVAL;
169 else if (buf[0] == 0x0b) /* IN TRANSITION */
170 err = -EAGAIN;
171 if (err < 0)
172 goto end;
173
174 info[0] = buf[4];
175 info[1] = buf[5];
176 info[2] = buf[6];
177 info[3] = buf[7];
178
179 err = 0;
180 end:
181 kfree(buf);
182 return err;
183 }
184 EXPORT_SYMBOL(avc_general_get_plug_info);
185
186 static DEFINE_SPINLOCK(transactions_lock);
187 static LIST_HEAD(transactions);
188
189 enum fcp_state {
190 STATE_PENDING,
191 STATE_BUS_RESET,
192 STATE_COMPLETE,
193 STATE_DEFERRED,
194 };
195
196 struct fcp_transaction {
197 struct list_head list;
198 struct fw_unit *unit;
199 void *response_buffer;
200 unsigned int response_size;
201 unsigned int response_match_bytes;
202 enum fcp_state state;
203 wait_queue_head_t wait;
204 bool deferrable;
205 };
206
207 /**
208 * fcp_avc_transaction - send an AV/C command and wait for its response
209 * @unit: a unit on the target device
210 * @command: a buffer containing the command frame; must be DMA-able
211 * @command_size: the size of @command
212 * @response: a buffer for the response frame
213 * @response_size: the maximum size of @response
214 * @response_match_bytes: a bitmap specifying the bytes used to detect the
215 * correct response frame
216 *
217 * This function sends a FCP command frame to the target and waits for the
218 * corresponding response frame to be returned.
219 *
220 * Because it is possible for multiple FCP transactions to be active at the
221 * same time, the correct response frame is detected by the value of certain
222 * bytes. These bytes must be set in @response before calling this function,
223 * and the corresponding bits must be set in @response_match_bytes.
224 *
225 * @command and @response can point to the same buffer.
226 *
227 * Returns the actual size of the response frame, or a negative error code.
228 */
fcp_avc_transaction(struct fw_unit * unit,const void * command,unsigned int command_size,void * response,unsigned int response_size,unsigned int response_match_bytes)229 int fcp_avc_transaction(struct fw_unit *unit,
230 const void *command, unsigned int command_size,
231 void *response, unsigned int response_size,
232 unsigned int response_match_bytes)
233 {
234 struct fcp_transaction t;
235 int tcode, ret, tries = 0;
236
237 t.unit = unit;
238 t.response_buffer = response;
239 t.response_size = response_size;
240 t.response_match_bytes = response_match_bytes;
241 t.state = STATE_PENDING;
242 init_waitqueue_head(&t.wait);
243
244 if (*(const u8 *)command == 0x00 || *(const u8 *)command == 0x03)
245 t.deferrable = true;
246
247 spin_lock_irq(&transactions_lock);
248 list_add_tail(&t.list, &transactions);
249 spin_unlock_irq(&transactions_lock);
250
251 for (;;) {
252 tcode = command_size == 4 ? TCODE_WRITE_QUADLET_REQUEST
253 : TCODE_WRITE_BLOCK_REQUEST;
254 ret = snd_fw_transaction(t.unit, tcode,
255 CSR_REGISTER_BASE + CSR_FCP_COMMAND,
256 (void *)command, command_size, 0);
257 if (ret < 0)
258 break;
259 deferred:
260 wait_event_timeout(t.wait, t.state != STATE_PENDING,
261 msecs_to_jiffies(FCP_TIMEOUT_MS));
262
263 if (t.state == STATE_DEFERRED) {
264 /*
265 * 'AV/C General Specification' define no time limit
266 * on command completion once an INTERIM response has
267 * been sent. but we promise to finish this function
268 * for a caller. Here we use FCP_TIMEOUT_MS for next
269 * interval. This is not in the specification.
270 */
271 t.state = STATE_PENDING;
272 goto deferred;
273 } else if (t.state == STATE_COMPLETE) {
274 ret = t.response_size;
275 break;
276 } else if (t.state == STATE_BUS_RESET) {
277 msleep(ERROR_DELAY_MS);
278 } else if (++tries >= ERROR_RETRIES) {
279 dev_err(&t.unit->device, "FCP command timed out\n");
280 ret = -EIO;
281 break;
282 }
283 }
284
285 spin_lock_irq(&transactions_lock);
286 list_del(&t.list);
287 spin_unlock_irq(&transactions_lock);
288
289 return ret;
290 }
291 EXPORT_SYMBOL(fcp_avc_transaction);
292
293 /**
294 * fcp_bus_reset - inform the target handler about a bus reset
295 * @unit: the unit that might be used by fcp_avc_transaction()
296 *
297 * This function must be called from the driver's .update handler to inform
298 * the FCP transaction handler that a bus reset has happened. Any pending FCP
299 * transactions are retried.
300 */
fcp_bus_reset(struct fw_unit * unit)301 void fcp_bus_reset(struct fw_unit *unit)
302 {
303 struct fcp_transaction *t;
304
305 spin_lock_irq(&transactions_lock);
306 list_for_each_entry(t, &transactions, list) {
307 if (t->unit == unit &&
308 (t->state == STATE_PENDING ||
309 t->state == STATE_DEFERRED)) {
310 t->state = STATE_BUS_RESET;
311 wake_up(&t->wait);
312 }
313 }
314 spin_unlock_irq(&transactions_lock);
315 }
316 EXPORT_SYMBOL(fcp_bus_reset);
317
318 /* checks whether the response matches the masked bytes in response_buffer */
is_matching_response(struct fcp_transaction * transaction,const void * response,size_t length)319 static bool is_matching_response(struct fcp_transaction *transaction,
320 const void *response, size_t length)
321 {
322 const u8 *p1, *p2;
323 unsigned int mask, i;
324
325 p1 = response;
326 p2 = transaction->response_buffer;
327 mask = transaction->response_match_bytes;
328
329 for (i = 0; ; ++i) {
330 if ((mask & 1) && p1[i] != p2[i])
331 return false;
332 mask >>= 1;
333 if (!mask)
334 return true;
335 if (--length == 0)
336 return false;
337 }
338 }
339
fcp_response(struct fw_card * card,struct fw_request * request,int tcode,int destination,int source,int generation,unsigned long long offset,void * data,size_t length,void * callback_data)340 static void fcp_response(struct fw_card *card, struct fw_request *request,
341 int tcode, int destination, int source,
342 int generation, unsigned long long offset,
343 void *data, size_t length, void *callback_data)
344 {
345 struct fcp_transaction *t;
346 unsigned long flags;
347
348 if (length < 1 || (*(const u8 *)data & 0xf0) != CTS_AVC)
349 return;
350
351 spin_lock_irqsave(&transactions_lock, flags);
352 list_for_each_entry(t, &transactions, list) {
353 struct fw_device *device = fw_parent_device(t->unit);
354 if (device->card != card ||
355 device->generation != generation)
356 continue;
357 smp_rmb(); /* node_id vs. generation */
358 if (device->node_id != source)
359 continue;
360
361 if (t->state == STATE_PENDING &&
362 is_matching_response(t, data, length)) {
363 if (t->deferrable && *(const u8 *)data == 0x0f) {
364 t->state = STATE_DEFERRED;
365 } else {
366 t->state = STATE_COMPLETE;
367 t->response_size = min_t(unsigned int, length,
368 t->response_size);
369 memcpy(t->response_buffer, data,
370 t->response_size);
371 }
372 wake_up(&t->wait);
373 }
374 }
375 spin_unlock_irqrestore(&transactions_lock, flags);
376 }
377
378 static struct fw_address_handler response_register_handler = {
379 .length = 0x200,
380 .address_callback = fcp_response,
381 };
382
fcp_module_init(void)383 static int __init fcp_module_init(void)
384 {
385 static const struct fw_address_region response_register_region = {
386 .start = CSR_REGISTER_BASE + CSR_FCP_RESPONSE,
387 .end = CSR_REGISTER_BASE + CSR_FCP_END,
388 };
389
390 fw_core_add_address_handler(&response_register_handler,
391 &response_register_region);
392
393 return 0;
394 }
395
fcp_module_exit(void)396 static void __exit fcp_module_exit(void)
397 {
398 WARN_ON(!list_empty(&transactions));
399 fw_core_remove_address_handler(&response_register_handler);
400 }
401
402 module_init(fcp_module_init);
403 module_exit(fcp_module_exit);
404
