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