1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * virtio-snd: Virtio sound device
4 * Copyright (C) 2021 OpenSynergy GmbH
5 */
6 #include <sound/pcm_params.h>
7
8 #include "virtio_card.h"
9
10 /*
11 * I/O messages lifetime
12 * ---------------------
13 *
14 * Allocation:
15 * Messages are initially allocated in the ops->hw_params() after the size and
16 * number of periods have been successfully negotiated.
17 *
18 * Freeing:
19 * Messages can be safely freed after the queue has been successfully flushed
20 * (RELEASE command in the ops->sync_stop()) and the ops->hw_free() has been
21 * called.
22 *
23 * When the substream stops, the ops->sync_stop() waits until the device has
24 * completed all pending messages. This wait can be interrupted either by a
25 * signal or due to a timeout. In this case, the device can still access
26 * messages even after calling ops->hw_free(). It can also issue an interrupt,
27 * and the interrupt handler will also try to access message structures.
28 *
29 * Therefore, freeing of already allocated messages occurs:
30 *
31 * - in ops->hw_params(), if this operator was called several times in a row,
32 * or if ops->hw_free() failed to free messages previously;
33 *
34 * - in ops->hw_free(), if the queue has been successfully flushed;
35 *
36 * - in dev->release().
37 */
38
39 /* Map for converting ALSA format to VirtIO format. */
40 struct virtsnd_a2v_format {
41 snd_pcm_format_t alsa_bit;
42 unsigned int vio_bit;
43 };
44
45 static const struct virtsnd_a2v_format g_a2v_format_map[] = {
46 { SNDRV_PCM_FORMAT_IMA_ADPCM, VIRTIO_SND_PCM_FMT_IMA_ADPCM },
47 { SNDRV_PCM_FORMAT_MU_LAW, VIRTIO_SND_PCM_FMT_MU_LAW },
48 { SNDRV_PCM_FORMAT_A_LAW, VIRTIO_SND_PCM_FMT_A_LAW },
49 { SNDRV_PCM_FORMAT_S8, VIRTIO_SND_PCM_FMT_S8 },
50 { SNDRV_PCM_FORMAT_U8, VIRTIO_SND_PCM_FMT_U8 },
51 { SNDRV_PCM_FORMAT_S16_LE, VIRTIO_SND_PCM_FMT_S16 },
52 { SNDRV_PCM_FORMAT_U16_LE, VIRTIO_SND_PCM_FMT_U16 },
53 { SNDRV_PCM_FORMAT_S18_3LE, VIRTIO_SND_PCM_FMT_S18_3 },
54 { SNDRV_PCM_FORMAT_U18_3LE, VIRTIO_SND_PCM_FMT_U18_3 },
55 { SNDRV_PCM_FORMAT_S20_3LE, VIRTIO_SND_PCM_FMT_S20_3 },
56 { SNDRV_PCM_FORMAT_U20_3LE, VIRTIO_SND_PCM_FMT_U20_3 },
57 { SNDRV_PCM_FORMAT_S24_3LE, VIRTIO_SND_PCM_FMT_S24_3 },
58 { SNDRV_PCM_FORMAT_U24_3LE, VIRTIO_SND_PCM_FMT_U24_3 },
59 { SNDRV_PCM_FORMAT_S20_LE, VIRTIO_SND_PCM_FMT_S20 },
60 { SNDRV_PCM_FORMAT_U20_LE, VIRTIO_SND_PCM_FMT_U20 },
61 { SNDRV_PCM_FORMAT_S24_LE, VIRTIO_SND_PCM_FMT_S24 },
62 { SNDRV_PCM_FORMAT_U24_LE, VIRTIO_SND_PCM_FMT_U24 },
63 { SNDRV_PCM_FORMAT_S32_LE, VIRTIO_SND_PCM_FMT_S32 },
64 { SNDRV_PCM_FORMAT_U32_LE, VIRTIO_SND_PCM_FMT_U32 },
65 { SNDRV_PCM_FORMAT_FLOAT_LE, VIRTIO_SND_PCM_FMT_FLOAT },
66 { SNDRV_PCM_FORMAT_FLOAT64_LE, VIRTIO_SND_PCM_FMT_FLOAT64 },
67 { SNDRV_PCM_FORMAT_DSD_U8, VIRTIO_SND_PCM_FMT_DSD_U8 },
68 { SNDRV_PCM_FORMAT_DSD_U16_LE, VIRTIO_SND_PCM_FMT_DSD_U16 },
69 { SNDRV_PCM_FORMAT_DSD_U32_LE, VIRTIO_SND_PCM_FMT_DSD_U32 },
70 { SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE,
71 VIRTIO_SND_PCM_FMT_IEC958_SUBFRAME }
72 };
73
74 /* Map for converting ALSA frame rate to VirtIO frame rate. */
75 struct virtsnd_a2v_rate {
76 unsigned int rate;
77 unsigned int vio_bit;
78 };
79
80 static const struct virtsnd_a2v_rate g_a2v_rate_map[] = {
81 { 5512, VIRTIO_SND_PCM_RATE_5512 },
82 { 8000, VIRTIO_SND_PCM_RATE_8000 },
83 { 11025, VIRTIO_SND_PCM_RATE_11025 },
84 { 16000, VIRTIO_SND_PCM_RATE_16000 },
85 { 22050, VIRTIO_SND_PCM_RATE_22050 },
86 { 32000, VIRTIO_SND_PCM_RATE_32000 },
87 { 44100, VIRTIO_SND_PCM_RATE_44100 },
88 { 48000, VIRTIO_SND_PCM_RATE_48000 },
89 { 64000, VIRTIO_SND_PCM_RATE_64000 },
90 { 88200, VIRTIO_SND_PCM_RATE_88200 },
91 { 96000, VIRTIO_SND_PCM_RATE_96000 },
92 { 176400, VIRTIO_SND_PCM_RATE_176400 },
93 { 192000, VIRTIO_SND_PCM_RATE_192000 }
94 };
95
96 static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream);
97
98 /**
99 * virtsnd_pcm_open() - Open the PCM substream.
100 * @substream: Kernel ALSA substream.
101 *
102 * Context: Process context.
103 * Return: 0 on success, -errno on failure.
104 */
virtsnd_pcm_open(struct snd_pcm_substream * substream)105 static int virtsnd_pcm_open(struct snd_pcm_substream *substream)
106 {
107 struct virtio_pcm *vpcm = snd_pcm_substream_chip(substream);
108 struct virtio_pcm_stream *vs = &vpcm->streams[substream->stream];
109 struct virtio_pcm_substream *vss = vs->substreams[substream->number];
110
111 substream->runtime->hw = vss->hw;
112 substream->private_data = vss;
113
114 snd_pcm_hw_constraint_integer(substream->runtime,
115 SNDRV_PCM_HW_PARAM_PERIODS);
116
117 vss->stopped = !!virtsnd_pcm_msg_pending_num(vss);
118 vss->suspended = false;
119
120 /*
121 * If the substream has already been used, then the I/O queue may be in
122 * an invalid state. Just in case, we do a check and try to return the
123 * queue to its original state, if necessary.
124 */
125 return virtsnd_pcm_sync_stop(substream);
126 }
127
128 /**
129 * virtsnd_pcm_close() - Close the PCM substream.
130 * @substream: Kernel ALSA substream.
131 *
132 * Context: Process context.
133 * Return: 0.
134 */
virtsnd_pcm_close(struct snd_pcm_substream * substream)135 static int virtsnd_pcm_close(struct snd_pcm_substream *substream)
136 {
137 return 0;
138 }
139
140 /**
141 * virtsnd_pcm_dev_set_params() - Set the parameters of the PCM substream on
142 * the device side.
143 * @vss: VirtIO PCM substream.
144 * @buffer_bytes: Size of the hardware buffer.
145 * @period_bytes: Size of the hardware period.
146 * @channels: Selected number of channels.
147 * @format: Selected sample format (SNDRV_PCM_FORMAT_XXX).
148 * @rate: Selected frame rate.
149 *
150 * Context: Any context that permits to sleep.
151 * Return: 0 on success, -errno on failure.
152 */
virtsnd_pcm_dev_set_params(struct virtio_pcm_substream * vss,unsigned int buffer_bytes,unsigned int period_bytes,unsigned int channels,snd_pcm_format_t format,unsigned int rate)153 static int virtsnd_pcm_dev_set_params(struct virtio_pcm_substream *vss,
154 unsigned int buffer_bytes,
155 unsigned int period_bytes,
156 unsigned int channels,
157 snd_pcm_format_t format,
158 unsigned int rate)
159 {
160 struct virtio_snd_msg *msg;
161 struct virtio_snd_pcm_set_params *request;
162 unsigned int i;
163 int vformat = -1;
164 int vrate = -1;
165
166 for (i = 0; i < ARRAY_SIZE(g_a2v_format_map); ++i)
167 if (g_a2v_format_map[i].alsa_bit == format) {
168 vformat = g_a2v_format_map[i].vio_bit;
169
170 break;
171 }
172
173 for (i = 0; i < ARRAY_SIZE(g_a2v_rate_map); ++i)
174 if (g_a2v_rate_map[i].rate == rate) {
175 vrate = g_a2v_rate_map[i].vio_bit;
176
177 break;
178 }
179
180 if (vformat == -1 || vrate == -1)
181 return -EINVAL;
182
183 msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_SET_PARAMS,
184 GFP_KERNEL);
185 if (!msg)
186 return -ENOMEM;
187
188 request = virtsnd_ctl_msg_request(msg);
189 request->buffer_bytes = cpu_to_le32(buffer_bytes);
190 request->period_bytes = cpu_to_le32(period_bytes);
191 request->channels = channels;
192 request->format = vformat;
193 request->rate = vrate;
194
195 if (vss->features & (1U << VIRTIO_SND_PCM_F_MSG_POLLING))
196 request->features |=
197 cpu_to_le32(1U << VIRTIO_SND_PCM_F_MSG_POLLING);
198
199 if (vss->features & (1U << VIRTIO_SND_PCM_F_EVT_XRUNS))
200 request->features |=
201 cpu_to_le32(1U << VIRTIO_SND_PCM_F_EVT_XRUNS);
202
203 return virtsnd_ctl_msg_send_sync(vss->snd, msg);
204 }
205
206 /**
207 * virtsnd_pcm_hw_params() - Set the parameters of the PCM substream.
208 * @substream: Kernel ALSA substream.
209 * @hw_params: Hardware parameters.
210 *
211 * Context: Process context.
212 * Return: 0 on success, -errno on failure.
213 */
virtsnd_pcm_hw_params(struct snd_pcm_substream * substream,struct snd_pcm_hw_params * hw_params)214 static int virtsnd_pcm_hw_params(struct snd_pcm_substream *substream,
215 struct snd_pcm_hw_params *hw_params)
216 {
217 struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
218 struct virtio_device *vdev = vss->snd->vdev;
219 int rc;
220
221 if (virtsnd_pcm_msg_pending_num(vss)) {
222 dev_err(&vdev->dev, "SID %u: invalid I/O queue state\n",
223 vss->sid);
224 return -EBADFD;
225 }
226
227 rc = virtsnd_pcm_dev_set_params(vss, params_buffer_bytes(hw_params),
228 params_period_bytes(hw_params),
229 params_channels(hw_params),
230 params_format(hw_params),
231 params_rate(hw_params));
232 if (rc)
233 return rc;
234
235 /*
236 * Free previously allocated messages if ops->hw_params() is called
237 * several times in a row, or if ops->hw_free() failed to free messages.
238 */
239 virtsnd_pcm_msg_free(vss);
240
241 return virtsnd_pcm_msg_alloc(vss, params_periods(hw_params),
242 params_period_bytes(hw_params));
243 }
244
245 /**
246 * virtsnd_pcm_hw_free() - Reset the parameters of the PCM substream.
247 * @substream: Kernel ALSA substream.
248 *
249 * Context: Process context.
250 * Return: 0
251 */
virtsnd_pcm_hw_free(struct snd_pcm_substream * substream)252 static int virtsnd_pcm_hw_free(struct snd_pcm_substream *substream)
253 {
254 struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
255
256 /* If the queue is flushed, we can safely free the messages here. */
257 if (!virtsnd_pcm_msg_pending_num(vss))
258 virtsnd_pcm_msg_free(vss);
259
260 return 0;
261 }
262
263 /**
264 * virtsnd_pcm_prepare() - Prepare the PCM substream.
265 * @substream: Kernel ALSA substream.
266 *
267 * Context: Process context.
268 * Return: 0 on success, -errno on failure.
269 */
virtsnd_pcm_prepare(struct snd_pcm_substream * substream)270 static int virtsnd_pcm_prepare(struct snd_pcm_substream *substream)
271 {
272 struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
273 struct virtio_device *vdev = vss->snd->vdev;
274 struct virtio_snd_msg *msg;
275
276 if (!vss->suspended) {
277 if (virtsnd_pcm_msg_pending_num(vss)) {
278 dev_err(&vdev->dev, "SID %u: invalid I/O queue state\n",
279 vss->sid);
280 return -EBADFD;
281 }
282
283 vss->buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
284 vss->hw_ptr = 0;
285 vss->msg_last_enqueued = -1;
286 } else {
287 struct snd_pcm_runtime *runtime = substream->runtime;
288 unsigned int buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
289 unsigned int period_bytes = snd_pcm_lib_period_bytes(substream);
290 int rc;
291
292 rc = virtsnd_pcm_dev_set_params(vss, buffer_bytes, period_bytes,
293 runtime->channels,
294 runtime->format, runtime->rate);
295 if (rc)
296 return rc;
297 }
298
299 vss->xfer_xrun = false;
300 vss->suspended = false;
301 vss->msg_count = 0;
302
303 msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_PREPARE,
304 GFP_KERNEL);
305 if (!msg)
306 return -ENOMEM;
307
308 return virtsnd_ctl_msg_send_sync(vss->snd, msg);
309 }
310
311 /**
312 * virtsnd_pcm_trigger() - Process command for the PCM substream.
313 * @substream: Kernel ALSA substream.
314 * @command: Substream command (SNDRV_PCM_TRIGGER_XXX).
315 *
316 * Context: Any context. Takes and releases the VirtIO substream spinlock.
317 * May take and release the tx/rx queue spinlock.
318 * Return: 0 on success, -errno on failure.
319 */
virtsnd_pcm_trigger(struct snd_pcm_substream * substream,int command)320 static int virtsnd_pcm_trigger(struct snd_pcm_substream *substream, int command)
321 {
322 struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
323 struct virtio_snd *snd = vss->snd;
324 struct virtio_snd_queue *queue;
325 struct virtio_snd_msg *msg;
326 unsigned long flags;
327 int rc;
328
329 switch (command) {
330 case SNDRV_PCM_TRIGGER_START:
331 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
332 queue = virtsnd_pcm_queue(vss);
333
334 spin_lock_irqsave(&queue->lock, flags);
335 spin_lock(&vss->lock);
336 rc = virtsnd_pcm_msg_send(vss);
337 if (!rc)
338 vss->xfer_enabled = true;
339 spin_unlock(&vss->lock);
340 spin_unlock_irqrestore(&queue->lock, flags);
341 if (rc)
342 return rc;
343
344 msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_START,
345 GFP_KERNEL);
346 if (!msg) {
347 spin_lock_irqsave(&vss->lock, flags);
348 vss->xfer_enabled = false;
349 spin_unlock_irqrestore(&vss->lock, flags);
350
351 return -ENOMEM;
352 }
353
354 return virtsnd_ctl_msg_send_sync(snd, msg);
355 case SNDRV_PCM_TRIGGER_SUSPEND:
356 vss->suspended = true;
357 fallthrough;
358 case SNDRV_PCM_TRIGGER_STOP:
359 vss->stopped = true;
360 fallthrough;
361 case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
362 spin_lock_irqsave(&vss->lock, flags);
363 vss->xfer_enabled = false;
364 spin_unlock_irqrestore(&vss->lock, flags);
365
366 msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_STOP,
367 GFP_KERNEL);
368 if (!msg)
369 return -ENOMEM;
370
371 return virtsnd_ctl_msg_send_sync(snd, msg);
372 default:
373 return -EINVAL;
374 }
375 }
376
377 /**
378 * virtsnd_pcm_sync_stop() - Synchronous PCM substream stop.
379 * @substream: Kernel ALSA substream.
380 *
381 * The function can be called both from the upper level or from the driver
382 * itself.
383 *
384 * Context: Process context. Takes and releases the VirtIO substream spinlock.
385 * Return: 0 on success, -errno on failure.
386 */
virtsnd_pcm_sync_stop(struct snd_pcm_substream * substream)387 static int virtsnd_pcm_sync_stop(struct snd_pcm_substream *substream)
388 {
389 struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
390 struct virtio_snd *snd = vss->snd;
391 struct virtio_snd_msg *msg;
392 unsigned int js = msecs_to_jiffies(virtsnd_msg_timeout_ms);
393 int rc;
394
395 cancel_work_sync(&vss->elapsed_period);
396
397 if (!vss->stopped)
398 return 0;
399
400 msg = virtsnd_pcm_ctl_msg_alloc(vss, VIRTIO_SND_R_PCM_RELEASE,
401 GFP_KERNEL);
402 if (!msg)
403 return -ENOMEM;
404
405 rc = virtsnd_ctl_msg_send_sync(snd, msg);
406 if (rc)
407 return rc;
408
409 /*
410 * The spec states that upon receipt of the RELEASE command "the device
411 * MUST complete all pending I/O messages for the specified stream ID".
412 * Thus, we consider the absence of I/O messages in the queue as an
413 * indication that the substream has been released.
414 */
415 rc = wait_event_interruptible_timeout(vss->msg_empty,
416 !virtsnd_pcm_msg_pending_num(vss),
417 js);
418 if (rc <= 0) {
419 dev_warn(&snd->vdev->dev, "SID %u: failed to flush I/O queue\n",
420 vss->sid);
421
422 return !rc ? -ETIMEDOUT : rc;
423 }
424
425 vss->stopped = false;
426
427 return 0;
428 }
429
430 /**
431 * virtsnd_pcm_pointer() - Get the current hardware position for the PCM
432 * substream.
433 * @substream: Kernel ALSA substream.
434 *
435 * Context: Any context. Takes and releases the VirtIO substream spinlock.
436 * Return: Hardware position in frames inside [0 ... buffer_size) range.
437 */
438 static snd_pcm_uframes_t
virtsnd_pcm_pointer(struct snd_pcm_substream * substream)439 virtsnd_pcm_pointer(struct snd_pcm_substream *substream)
440 {
441 struct virtio_pcm_substream *vss = snd_pcm_substream_chip(substream);
442 snd_pcm_uframes_t hw_ptr = SNDRV_PCM_POS_XRUN;
443 unsigned long flags;
444
445 spin_lock_irqsave(&vss->lock, flags);
446 if (!vss->xfer_xrun)
447 hw_ptr = bytes_to_frames(substream->runtime, vss->hw_ptr);
448 spin_unlock_irqrestore(&vss->lock, flags);
449
450 return hw_ptr;
451 }
452
453 /* PCM substream operators map. */
454 const struct snd_pcm_ops virtsnd_pcm_ops = {
455 .open = virtsnd_pcm_open,
456 .close = virtsnd_pcm_close,
457 .ioctl = snd_pcm_lib_ioctl,
458 .hw_params = virtsnd_pcm_hw_params,
459 .hw_free = virtsnd_pcm_hw_free,
460 .prepare = virtsnd_pcm_prepare,
461 .trigger = virtsnd_pcm_trigger,
462 .sync_stop = virtsnd_pcm_sync_stop,
463 .pointer = virtsnd_pcm_pointer,
464 };
465