1 // SPDX-License-Identifier: GPL-2.0 OR MIT
2
3 /*
4 * Xen para-virtual sound device
5 *
6 * Copyright (C) 2016-2018 EPAM Systems Inc.
7 *
8 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
9 */
10
11 #include <xen/events.h>
12 #include <xen/grant_table.h>
13 #include <xen/xen.h>
14 #include <xen/xenbus.h>
15
16 #include "xen_snd_front.h"
17 #include "xen_snd_front_alsa.h"
18 #include "xen_snd_front_cfg.h"
19 #include "xen_snd_front_evtchnl.h"
20
evtchnl_interrupt_req(int irq,void * dev_id)21 static irqreturn_t evtchnl_interrupt_req(int irq, void *dev_id)
22 {
23 struct xen_snd_front_evtchnl *channel = dev_id;
24 struct xen_snd_front_info *front_info = channel->front_info;
25 struct xensnd_resp *resp;
26 RING_IDX i, rp;
27
28 if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
29 return IRQ_HANDLED;
30
31 mutex_lock(&channel->ring_io_lock);
32
33 again:
34 rp = channel->u.req.ring.sring->rsp_prod;
35 /* Ensure we see queued responses up to rp. */
36 rmb();
37
38 /*
39 * Assume that the backend is trusted to always write sane values
40 * to the ring counters, so no overflow checks on frontend side
41 * are required.
42 */
43 for (i = channel->u.req.ring.rsp_cons; i != rp; i++) {
44 resp = RING_GET_RESPONSE(&channel->u.req.ring, i);
45 if (resp->id != channel->evt_id)
46 continue;
47 switch (resp->operation) {
48 case XENSND_OP_OPEN:
49 /* fall through */
50 case XENSND_OP_CLOSE:
51 /* fall through */
52 case XENSND_OP_READ:
53 /* fall through */
54 case XENSND_OP_WRITE:
55 /* fall through */
56 case XENSND_OP_TRIGGER:
57 channel->u.req.resp_status = resp->status;
58 complete(&channel->u.req.completion);
59 break;
60 case XENSND_OP_HW_PARAM_QUERY:
61 channel->u.req.resp_status = resp->status;
62 channel->u.req.resp.hw_param =
63 resp->resp.hw_param;
64 complete(&channel->u.req.completion);
65 break;
66
67 default:
68 dev_err(&front_info->xb_dev->dev,
69 "Operation %d is not supported\n",
70 resp->operation);
71 break;
72 }
73 }
74
75 channel->u.req.ring.rsp_cons = i;
76 if (i != channel->u.req.ring.req_prod_pvt) {
77 int more_to_do;
78
79 RING_FINAL_CHECK_FOR_RESPONSES(&channel->u.req.ring,
80 more_to_do);
81 if (more_to_do)
82 goto again;
83 } else {
84 channel->u.req.ring.sring->rsp_event = i + 1;
85 }
86
87 mutex_unlock(&channel->ring_io_lock);
88 return IRQ_HANDLED;
89 }
90
evtchnl_interrupt_evt(int irq,void * dev_id)91 static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id)
92 {
93 struct xen_snd_front_evtchnl *channel = dev_id;
94 struct xensnd_event_page *page = channel->u.evt.page;
95 u32 cons, prod;
96
97 if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
98 return IRQ_HANDLED;
99
100 mutex_lock(&channel->ring_io_lock);
101
102 prod = page->in_prod;
103 /* Ensure we see ring contents up to prod. */
104 virt_rmb();
105 if (prod == page->in_cons)
106 goto out;
107
108 /*
109 * Assume that the backend is trusted to always write sane values
110 * to the ring counters, so no overflow checks on frontend side
111 * are required.
112 */
113 for (cons = page->in_cons; cons != prod; cons++) {
114 struct xensnd_evt *event;
115
116 event = &XENSND_IN_RING_REF(page, cons);
117 if (unlikely(event->id != channel->evt_id++))
118 continue;
119
120 switch (event->type) {
121 case XENSND_EVT_CUR_POS:
122 xen_snd_front_alsa_handle_cur_pos(channel,
123 event->op.cur_pos.position);
124 break;
125 }
126 }
127
128 page->in_cons = cons;
129 /* Ensure ring contents. */
130 virt_wmb();
131
132 out:
133 mutex_unlock(&channel->ring_io_lock);
134 return IRQ_HANDLED;
135 }
136
xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl * channel)137 void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *channel)
138 {
139 int notify;
140
141 channel->u.req.ring.req_prod_pvt++;
142 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&channel->u.req.ring, notify);
143 if (notify)
144 notify_remote_via_irq(channel->irq);
145 }
146
evtchnl_free(struct xen_snd_front_info * front_info,struct xen_snd_front_evtchnl * channel)147 static void evtchnl_free(struct xen_snd_front_info *front_info,
148 struct xen_snd_front_evtchnl *channel)
149 {
150 unsigned long page = 0;
151
152 if (channel->type == EVTCHNL_TYPE_REQ)
153 page = (unsigned long)channel->u.req.ring.sring;
154 else if (channel->type == EVTCHNL_TYPE_EVT)
155 page = (unsigned long)channel->u.evt.page;
156
157 if (!page)
158 return;
159
160 channel->state = EVTCHNL_STATE_DISCONNECTED;
161 if (channel->type == EVTCHNL_TYPE_REQ) {
162 /* Release all who still waits for response if any. */
163 channel->u.req.resp_status = -EIO;
164 complete_all(&channel->u.req.completion);
165 }
166
167 if (channel->irq)
168 unbind_from_irqhandler(channel->irq, channel);
169
170 if (channel->port)
171 xenbus_free_evtchn(front_info->xb_dev, channel->port);
172
173 /* End access and free the page. */
174 if (channel->gref != GRANT_INVALID_REF)
175 gnttab_end_foreign_access(channel->gref, 0, page);
176 else
177 free_page(page);
178
179 memset(channel, 0, sizeof(*channel));
180 }
181
xen_snd_front_evtchnl_free_all(struct xen_snd_front_info * front_info)182 void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info)
183 {
184 int i;
185
186 if (!front_info->evt_pairs)
187 return;
188
189 for (i = 0; i < front_info->num_evt_pairs; i++) {
190 evtchnl_free(front_info, &front_info->evt_pairs[i].req);
191 evtchnl_free(front_info, &front_info->evt_pairs[i].evt);
192 }
193
194 kfree(front_info->evt_pairs);
195 front_info->evt_pairs = NULL;
196 }
197
evtchnl_alloc(struct xen_snd_front_info * front_info,int index,struct xen_snd_front_evtchnl * channel,enum xen_snd_front_evtchnl_type type)198 static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
199 struct xen_snd_front_evtchnl *channel,
200 enum xen_snd_front_evtchnl_type type)
201 {
202 struct xenbus_device *xb_dev = front_info->xb_dev;
203 unsigned long page;
204 grant_ref_t gref;
205 irq_handler_t handler;
206 char *handler_name = NULL;
207 int ret;
208
209 memset(channel, 0, sizeof(*channel));
210 channel->type = type;
211 channel->index = index;
212 channel->front_info = front_info;
213 channel->state = EVTCHNL_STATE_DISCONNECTED;
214 channel->gref = GRANT_INVALID_REF;
215 page = get_zeroed_page(GFP_KERNEL);
216 if (!page) {
217 ret = -ENOMEM;
218 goto fail;
219 }
220
221 handler_name = kasprintf(GFP_KERNEL, "%s-%s", XENSND_DRIVER_NAME,
222 type == EVTCHNL_TYPE_REQ ?
223 XENSND_FIELD_RING_REF :
224 XENSND_FIELD_EVT_RING_REF);
225 if (!handler_name) {
226 ret = -ENOMEM;
227 goto fail;
228 }
229
230 mutex_init(&channel->ring_io_lock);
231
232 if (type == EVTCHNL_TYPE_REQ) {
233 struct xen_sndif_sring *sring = (struct xen_sndif_sring *)page;
234
235 init_completion(&channel->u.req.completion);
236 mutex_init(&channel->u.req.req_io_lock);
237 SHARED_RING_INIT(sring);
238 FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE);
239
240 ret = xenbus_grant_ring(xb_dev, sring, 1, &gref);
241 if (ret < 0) {
242 channel->u.req.ring.sring = NULL;
243 goto fail;
244 }
245
246 handler = evtchnl_interrupt_req;
247 } else {
248 ret = gnttab_grant_foreign_access(xb_dev->otherend_id,
249 virt_to_gfn((void *)page), 0);
250 if (ret < 0)
251 goto fail;
252
253 channel->u.evt.page = (struct xensnd_event_page *)page;
254 gref = ret;
255 handler = evtchnl_interrupt_evt;
256 }
257
258 channel->gref = gref;
259
260 ret = xenbus_alloc_evtchn(xb_dev, &channel->port);
261 if (ret < 0)
262 goto fail;
263
264 ret = bind_evtchn_to_irq(channel->port);
265 if (ret < 0) {
266 dev_err(&xb_dev->dev,
267 "Failed to bind IRQ for domid %d port %d: %d\n",
268 front_info->xb_dev->otherend_id, channel->port, ret);
269 goto fail;
270 }
271
272 channel->irq = ret;
273
274 ret = request_threaded_irq(channel->irq, NULL, handler,
275 IRQF_ONESHOT, handler_name, channel);
276 if (ret < 0) {
277 dev_err(&xb_dev->dev, "Failed to request IRQ %d: %d\n",
278 channel->irq, ret);
279 goto fail;
280 }
281
282 kfree(handler_name);
283 return 0;
284
285 fail:
286 if (page)
287 free_page(page);
288 kfree(handler_name);
289 dev_err(&xb_dev->dev, "Failed to allocate ring: %d\n", ret);
290 return ret;
291 }
292
xen_snd_front_evtchnl_create_all(struct xen_snd_front_info * front_info,int num_streams)293 int xen_snd_front_evtchnl_create_all(struct xen_snd_front_info *front_info,
294 int num_streams)
295 {
296 struct xen_front_cfg_card *cfg = &front_info->cfg;
297 struct device *dev = &front_info->xb_dev->dev;
298 int d, ret = 0;
299
300 front_info->evt_pairs =
301 kcalloc(num_streams,
302 sizeof(struct xen_snd_front_evtchnl_pair),
303 GFP_KERNEL);
304 if (!front_info->evt_pairs)
305 return -ENOMEM;
306
307 /* Iterate over devices and their streams and create event channels. */
308 for (d = 0; d < cfg->num_pcm_instances; d++) {
309 struct xen_front_cfg_pcm_instance *pcm_instance;
310 int s, index;
311
312 pcm_instance = &cfg->pcm_instances[d];
313
314 for (s = 0; s < pcm_instance->num_streams_pb; s++) {
315 index = pcm_instance->streams_pb[s].index;
316
317 ret = evtchnl_alloc(front_info, index,
318 &front_info->evt_pairs[index].req,
319 EVTCHNL_TYPE_REQ);
320 if (ret < 0) {
321 dev_err(dev, "Error allocating control channel\n");
322 goto fail;
323 }
324
325 ret = evtchnl_alloc(front_info, index,
326 &front_info->evt_pairs[index].evt,
327 EVTCHNL_TYPE_EVT);
328 if (ret < 0) {
329 dev_err(dev, "Error allocating in-event channel\n");
330 goto fail;
331 }
332 }
333
334 for (s = 0; s < pcm_instance->num_streams_cap; s++) {
335 index = pcm_instance->streams_cap[s].index;
336
337 ret = evtchnl_alloc(front_info, index,
338 &front_info->evt_pairs[index].req,
339 EVTCHNL_TYPE_REQ);
340 if (ret < 0) {
341 dev_err(dev, "Error allocating control channel\n");
342 goto fail;
343 }
344
345 ret = evtchnl_alloc(front_info, index,
346 &front_info->evt_pairs[index].evt,
347 EVTCHNL_TYPE_EVT);
348 if (ret < 0) {
349 dev_err(dev, "Error allocating in-event channel\n");
350 goto fail;
351 }
352 }
353 }
354
355 front_info->num_evt_pairs = num_streams;
356 return 0;
357
358 fail:
359 xen_snd_front_evtchnl_free_all(front_info);
360 return ret;
361 }
362
evtchnl_publish(struct xenbus_transaction xbt,struct xen_snd_front_evtchnl * channel,const char * path,const char * node_ring,const char * node_chnl)363 static int evtchnl_publish(struct xenbus_transaction xbt,
364 struct xen_snd_front_evtchnl *channel,
365 const char *path, const char *node_ring,
366 const char *node_chnl)
367 {
368 struct xenbus_device *xb_dev = channel->front_info->xb_dev;
369 int ret;
370
371 /* Write control channel ring reference. */
372 ret = xenbus_printf(xbt, path, node_ring, "%u", channel->gref);
373 if (ret < 0) {
374 dev_err(&xb_dev->dev, "Error writing ring-ref: %d\n", ret);
375 return ret;
376 }
377
378 /* Write event channel ring reference. */
379 ret = xenbus_printf(xbt, path, node_chnl, "%u", channel->port);
380 if (ret < 0) {
381 dev_err(&xb_dev->dev, "Error writing event channel: %d\n", ret);
382 return ret;
383 }
384
385 return 0;
386 }
387
xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info * front_info)388 int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info)
389 {
390 struct xen_front_cfg_card *cfg = &front_info->cfg;
391 struct xenbus_transaction xbt;
392 int ret, d;
393
394 again:
395 ret = xenbus_transaction_start(&xbt);
396 if (ret < 0) {
397 xenbus_dev_fatal(front_info->xb_dev, ret,
398 "starting transaction");
399 return ret;
400 }
401
402 for (d = 0; d < cfg->num_pcm_instances; d++) {
403 struct xen_front_cfg_pcm_instance *pcm_instance;
404 int s, index;
405
406 pcm_instance = &cfg->pcm_instances[d];
407
408 for (s = 0; s < pcm_instance->num_streams_pb; s++) {
409 index = pcm_instance->streams_pb[s].index;
410
411 ret = evtchnl_publish(xbt,
412 &front_info->evt_pairs[index].req,
413 pcm_instance->streams_pb[s].xenstore_path,
414 XENSND_FIELD_RING_REF,
415 XENSND_FIELD_EVT_CHNL);
416 if (ret < 0)
417 goto fail;
418
419 ret = evtchnl_publish(xbt,
420 &front_info->evt_pairs[index].evt,
421 pcm_instance->streams_pb[s].xenstore_path,
422 XENSND_FIELD_EVT_RING_REF,
423 XENSND_FIELD_EVT_EVT_CHNL);
424 if (ret < 0)
425 goto fail;
426 }
427
428 for (s = 0; s < pcm_instance->num_streams_cap; s++) {
429 index = pcm_instance->streams_cap[s].index;
430
431 ret = evtchnl_publish(xbt,
432 &front_info->evt_pairs[index].req,
433 pcm_instance->streams_cap[s].xenstore_path,
434 XENSND_FIELD_RING_REF,
435 XENSND_FIELD_EVT_CHNL);
436 if (ret < 0)
437 goto fail;
438
439 ret = evtchnl_publish(xbt,
440 &front_info->evt_pairs[index].evt,
441 pcm_instance->streams_cap[s].xenstore_path,
442 XENSND_FIELD_EVT_RING_REF,
443 XENSND_FIELD_EVT_EVT_CHNL);
444 if (ret < 0)
445 goto fail;
446 }
447 }
448 ret = xenbus_transaction_end(xbt, 0);
449 if (ret < 0) {
450 if (ret == -EAGAIN)
451 goto again;
452
453 xenbus_dev_fatal(front_info->xb_dev, ret,
454 "completing transaction");
455 goto fail_to_end;
456 }
457 return 0;
458 fail:
459 xenbus_transaction_end(xbt, 1);
460 fail_to_end:
461 xenbus_dev_fatal(front_info->xb_dev, ret, "writing XenStore");
462 return ret;
463 }
464
xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair * evt_pair,bool is_connected)465 void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair,
466 bool is_connected)
467 {
468 enum xen_snd_front_evtchnl_state state;
469
470 if (is_connected)
471 state = EVTCHNL_STATE_CONNECTED;
472 else
473 state = EVTCHNL_STATE_DISCONNECTED;
474
475 mutex_lock(&evt_pair->req.ring_io_lock);
476 evt_pair->req.state = state;
477 mutex_unlock(&evt_pair->req.ring_io_lock);
478
479 mutex_lock(&evt_pair->evt.ring_io_lock);
480 evt_pair->evt.state = state;
481 mutex_unlock(&evt_pair->evt.ring_io_lock);
482 }
483
xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair * evt_pair)484 void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair)
485 {
486 mutex_lock(&evt_pair->req.ring_io_lock);
487 evt_pair->req.evt_next_id = 0;
488 mutex_unlock(&evt_pair->req.ring_io_lock);
489
490 mutex_lock(&evt_pair->evt.ring_io_lock);
491 evt_pair->evt.evt_next_id = 0;
492 mutex_unlock(&evt_pair->evt.ring_io_lock);
493 }
494
495
