sound/virtio/virtio_pcm_ops.c

   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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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
 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 };