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pcm.c

/*
 *  Digital Audio (PCM) abstract layer
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <sound/driver.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/mutex.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/pcm.h>
#include <sound/control.h>
#include <sound/info.h>

MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Abramo Bagnara <abramo@alsa-project.org>");
MODULE_DESCRIPTION("Midlevel PCM code for ALSA.");
MODULE_LICENSE("GPL");

static LIST_HEAD(snd_pcm_devices);
static LIST_HEAD(snd_pcm_notify_list);
static DEFINE_MUTEX(register_mutex);

static int snd_pcm_free(struct snd_pcm *pcm);
static int snd_pcm_dev_free(struct snd_device *device);
static int snd_pcm_dev_register(struct snd_device *device);
static int snd_pcm_dev_disconnect(struct snd_device *device);

static struct snd_pcm *snd_pcm_search(struct snd_card *card, int device)
{
      struct snd_pcm *pcm;

      list_for_each_entry(pcm, &snd_pcm_devices, list) {
            if (pcm->card == card && pcm->device == device)
                  return pcm;
      }
      return NULL;
}

static int snd_pcm_control_ioctl(struct snd_card *card,
                         struct snd_ctl_file *control,
                         unsigned int cmd, unsigned long arg)
{
      switch (cmd) {
      case SNDRV_CTL_IOCTL_PCM_NEXT_DEVICE:
            {
                  int device;

                  if (get_user(device, (int __user *)arg))
                        return -EFAULT;
                  mutex_lock(&register_mutex);
                  device = device < 0 ? 0 : device + 1;
                  while (device < SNDRV_PCM_DEVICES) {
                        if (snd_pcm_search(card, device))
                              break;
                        device++;
                  }
                  if (device == SNDRV_PCM_DEVICES)
                        device = -1;
                  mutex_unlock(&register_mutex);
                  if (put_user(device, (int __user *)arg))
                        return -EFAULT;
                  return 0;
            }
      case SNDRV_CTL_IOCTL_PCM_INFO:
            {
                  struct snd_pcm_info __user *info;
                  unsigned int device, subdevice;
                  int stream;
                  struct snd_pcm *pcm;
                  struct snd_pcm_str *pstr;
                  struct snd_pcm_substream *substream;
                  int err;

                  info = (struct snd_pcm_info __user *)arg;
                  if (get_user(device, &info->device))
                        return -EFAULT;
                  if (get_user(stream, &info->stream))
                        return -EFAULT;
                  if (stream < 0 || stream > 1)
                        return -EINVAL;
                  if (get_user(subdevice, &info->subdevice))
                        return -EFAULT;
                  mutex_lock(&register_mutex);
                  pcm = snd_pcm_search(card, device);
                  if (pcm == NULL) {
                        err = -ENXIO;
                        goto _error;
                  }
                  pstr = &pcm->streams[stream];
                  if (pstr->substream_count == 0) {
                        err = -ENOENT;
                        goto _error;
                  }
                  if (subdevice >= pstr->substream_count) {
                        err = -ENXIO;
                        goto _error;
                  }
                  for (substream = pstr->substream; substream;
                       substream = substream->next)
                        if (substream->number == (int)subdevice)
                              break;
                  if (substream == NULL) {
                        err = -ENXIO;
                        goto _error;
                  }
                  err = snd_pcm_info_user(substream, info);
            _error:
                  mutex_unlock(&register_mutex);
                  return err;
            }
      case SNDRV_CTL_IOCTL_PCM_PREFER_SUBDEVICE:
            {
                  int val;
                  
                  if (get_user(val, (int __user *)arg))
                        return -EFAULT;
                  control->prefer_pcm_subdevice = val;
                  return 0;
            }
      }
      return -ENOIOCTLCMD;
}

#ifdef CONFIG_SND_VERBOSE_PROCFS

#define STATE(v) [SNDRV_PCM_STATE_##v] = #v
#define STREAM(v) [SNDRV_PCM_STREAM_##v] = #v
#define READY(v) [SNDRV_PCM_READY_##v] = #v
#define XRUN(v) [SNDRV_PCM_XRUN_##v] = #v
#define SILENCE(v) [SNDRV_PCM_SILENCE_##v] = #v
#define TSTAMP(v) [SNDRV_PCM_TSTAMP_##v] = #v
#define ACCESS(v) [SNDRV_PCM_ACCESS_##v] = #v
#define START(v) [SNDRV_PCM_START_##v] = #v
#define FORMAT(v) [SNDRV_PCM_FORMAT_##v] = #v
#define SUBFORMAT(v) [SNDRV_PCM_SUBFORMAT_##v] = #v 

static char *snd_pcm_format_names[] = {
      FORMAT(S8),
      FORMAT(U8),
      FORMAT(S16_LE),
      FORMAT(S16_BE),
      FORMAT(U16_LE),
      FORMAT(U16_BE),
      FORMAT(S24_LE),
      FORMAT(S24_BE),
      FORMAT(U24_LE),
      FORMAT(U24_BE),
      FORMAT(S32_LE),
      FORMAT(S32_BE),
      FORMAT(U32_LE),
      FORMAT(U32_BE),
      FORMAT(FLOAT_LE),
      FORMAT(FLOAT_BE),
      FORMAT(FLOAT64_LE),
      FORMAT(FLOAT64_BE),
      FORMAT(IEC958_SUBFRAME_LE),
      FORMAT(IEC958_SUBFRAME_BE),
      FORMAT(MU_LAW),
      FORMAT(A_LAW),
      FORMAT(IMA_ADPCM),
      FORMAT(MPEG),
      FORMAT(GSM),
      FORMAT(SPECIAL),
      FORMAT(S24_3LE),
      FORMAT(S24_3BE),
      FORMAT(U24_3LE),
      FORMAT(U24_3BE),
      FORMAT(S20_3LE),
      FORMAT(S20_3BE),
      FORMAT(U20_3LE),
      FORMAT(U20_3BE),
      FORMAT(S18_3LE),
      FORMAT(S18_3BE),
      FORMAT(U18_3LE),
      FORMAT(U18_3BE),
};

static const char *snd_pcm_format_name(snd_pcm_format_t format)
{
      return snd_pcm_format_names[format];
}

static char *snd_pcm_stream_names[] = {
      STREAM(PLAYBACK),
      STREAM(CAPTURE),
};

static char *snd_pcm_state_names[] = {
      STATE(OPEN),
      STATE(SETUP),
      STATE(PREPARED),
      STATE(RUNNING),
      STATE(XRUN),
      STATE(DRAINING),
      STATE(PAUSED),
      STATE(SUSPENDED),
};

static char *snd_pcm_access_names[] = {
      ACCESS(MMAP_INTERLEAVED), 
      ACCESS(MMAP_NONINTERLEAVED),
      ACCESS(MMAP_COMPLEX),
      ACCESS(RW_INTERLEAVED),
      ACCESS(RW_NONINTERLEAVED),
};

static char *snd_pcm_subformat_names[] = {
      SUBFORMAT(STD), 
};

static char *snd_pcm_tstamp_mode_names[] = {
      TSTAMP(NONE),
      TSTAMP(MMAP),
};

static const char *snd_pcm_stream_name(int stream)
{
      snd_assert(stream <= SNDRV_PCM_STREAM_LAST, return NULL);
      return snd_pcm_stream_names[stream];
}

static const char *snd_pcm_access_name(snd_pcm_access_t access)
{
      return snd_pcm_access_names[access];
}

static const char *snd_pcm_subformat_name(snd_pcm_subformat_t subformat)
{
      return snd_pcm_subformat_names[subformat];
}

static const char *snd_pcm_tstamp_mode_name(int mode)
{
      snd_assert(mode <= SNDRV_PCM_TSTAMP_LAST, return NULL);
      return snd_pcm_tstamp_mode_names[mode];
}

static const char *snd_pcm_state_name(snd_pcm_state_t state)
{
      return snd_pcm_state_names[state];
}

#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
#include <linux/soundcard.h>

static const char *snd_pcm_oss_format_name(int format)
{
      switch (format) {
      case AFMT_MU_LAW:
            return "MU_LAW";
      case AFMT_A_LAW:
            return "A_LAW";
      case AFMT_IMA_ADPCM:
            return "IMA_ADPCM";
      case AFMT_U8:
            return "U8";
      case AFMT_S16_LE:
            return "S16_LE";
      case AFMT_S16_BE:
            return "S16_BE";
      case AFMT_S8:
            return "S8";
      case AFMT_U16_LE:
            return "U16_LE";
      case AFMT_U16_BE:
            return "U16_BE";
      case AFMT_MPEG:
            return "MPEG";
      default:
            return "unknown";
      }
}
#endif

static void snd_pcm_proc_info_read(struct snd_pcm_substream *substream,
                           struct snd_info_buffer *buffer)
{
      struct snd_pcm_info *info;
      int err;

      if (! substream)
            return;

      info = kmalloc(sizeof(*info), GFP_KERNEL);
      if (! info) {
            printk(KERN_DEBUG "snd_pcm_proc_info_read: cannot malloc\n");
            return;
      }

      err = snd_pcm_info(substream, info);
      if (err < 0) {
            snd_iprintf(buffer, "error %d\n", err);
            kfree(info);
            return;
      }
      snd_iprintf(buffer, "card: %d\n", info->card);
      snd_iprintf(buffer, "device: %d\n", info->device);
      snd_iprintf(buffer, "subdevice: %d\n", info->subdevice);
      snd_iprintf(buffer, "stream: %s\n", snd_pcm_stream_name(info->stream));
      snd_iprintf(buffer, "id: %s\n", info->id);
      snd_iprintf(buffer, "name: %s\n", info->name);
      snd_iprintf(buffer, "subname: %s\n", info->subname);
      snd_iprintf(buffer, "class: %d\n", info->dev_class);
      snd_iprintf(buffer, "subclass: %d\n", info->dev_subclass);
      snd_iprintf(buffer, "subdevices_count: %d\n", info->subdevices_count);
      snd_iprintf(buffer, "subdevices_avail: %d\n", info->subdevices_avail);
      kfree(info);
}

static void snd_pcm_stream_proc_info_read(struct snd_info_entry *entry,
                                struct snd_info_buffer *buffer)
{
      snd_pcm_proc_info_read(((struct snd_pcm_str *)entry->private_data)->substream,
                         buffer);
}

static void snd_pcm_substream_proc_info_read(struct snd_info_entry *entry,
                                   struct snd_info_buffer *buffer)
{
      snd_pcm_proc_info_read((struct snd_pcm_substream *)entry->private_data,
                         buffer);
}

static void snd_pcm_substream_proc_hw_params_read(struct snd_info_entry *entry,
                                      struct snd_info_buffer *buffer)
{
      struct snd_pcm_substream *substream = entry->private_data;
      struct snd_pcm_runtime *runtime = substream->runtime;
      if (!runtime) {
            snd_iprintf(buffer, "closed\n");
            return;
      }
      if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
            snd_iprintf(buffer, "no setup\n");
            return;
      }
      snd_iprintf(buffer, "access: %s\n", snd_pcm_access_name(runtime->access));
      snd_iprintf(buffer, "format: %s\n", snd_pcm_format_name(runtime->format));
      snd_iprintf(buffer, "subformat: %s\n", snd_pcm_subformat_name(runtime->subformat));
      snd_iprintf(buffer, "channels: %u\n", runtime->channels);   
      snd_iprintf(buffer, "rate: %u (%u/%u)\n", runtime->rate, runtime->rate_num, runtime->rate_den); 
      snd_iprintf(buffer, "period_size: %lu\n", runtime->period_size);  
      snd_iprintf(buffer, "buffer_size: %lu\n", runtime->buffer_size);  
      snd_iprintf(buffer, "tick_time: %u\n", runtime->tick_time);
#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
      if (substream->oss.oss) {
            snd_iprintf(buffer, "OSS format: %s\n", snd_pcm_oss_format_name(runtime->oss.format));
            snd_iprintf(buffer, "OSS channels: %u\n", runtime->oss.channels); 
            snd_iprintf(buffer, "OSS rate: %u\n", runtime->oss.rate);
            snd_iprintf(buffer, "OSS period bytes: %lu\n", (unsigned long)runtime->oss.period_bytes);
            snd_iprintf(buffer, "OSS periods: %u\n", runtime->oss.periods);
            snd_iprintf(buffer, "OSS period frames: %lu\n", (unsigned long)runtime->oss.period_frames);
      }
#endif
}

static void snd_pcm_substream_proc_sw_params_read(struct snd_info_entry *entry,
                                      struct snd_info_buffer *buffer)
{
      struct snd_pcm_substream *substream = entry->private_data;
      struct snd_pcm_runtime *runtime = substream->runtime;
      if (!runtime) {
            snd_iprintf(buffer, "closed\n");
            return;
      }
      if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
            snd_iprintf(buffer, "no setup\n");
            return;
      }
      snd_iprintf(buffer, "tstamp_mode: %s\n", snd_pcm_tstamp_mode_name(runtime->tstamp_mode));
      snd_iprintf(buffer, "period_step: %u\n", runtime->period_step);
      snd_iprintf(buffer, "sleep_min: %u\n", runtime->sleep_min);
      snd_iprintf(buffer, "avail_min: %lu\n", runtime->control->avail_min);
      snd_iprintf(buffer, "xfer_align: %lu\n", runtime->xfer_align);
      snd_iprintf(buffer, "start_threshold: %lu\n", runtime->start_threshold);
      snd_iprintf(buffer, "stop_threshold: %lu\n", runtime->stop_threshold);
      snd_iprintf(buffer, "silence_threshold: %lu\n", runtime->silence_threshold);
      snd_iprintf(buffer, "silence_size: %lu\n", runtime->silence_size);
      snd_iprintf(buffer, "boundary: %lu\n", runtime->boundary);
}

static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry,
                                     struct snd_info_buffer *buffer)
{
      struct snd_pcm_substream *substream = entry->private_data;
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct snd_pcm_status status;
      int err;
      if (!runtime) {
            snd_iprintf(buffer, "closed\n");
            return;
      }
      memset(&status, 0, sizeof(status));
      err = snd_pcm_status(substream, &status);
      if (err < 0) {
            snd_iprintf(buffer, "error %d\n", err);
            return;
      }
      snd_iprintf(buffer, "state: %s\n", snd_pcm_state_name(status.state));
      snd_iprintf(buffer, "trigger_time: %ld.%09ld\n",
            status.trigger_tstamp.tv_sec, status.trigger_tstamp.tv_nsec);
      snd_iprintf(buffer, "tstamp      : %ld.%09ld\n",
            status.tstamp.tv_sec, status.tstamp.tv_nsec);
      snd_iprintf(buffer, "delay       : %ld\n", status.delay);
      snd_iprintf(buffer, "avail       : %ld\n", status.avail);
      snd_iprintf(buffer, "avail_max   : %ld\n", status.avail_max);
      snd_iprintf(buffer, "-----\n");
      snd_iprintf(buffer, "hw_ptr      : %ld\n", runtime->status->hw_ptr);
      snd_iprintf(buffer, "appl_ptr    : %ld\n", runtime->control->appl_ptr);
}

#ifdef CONFIG_SND_PCM_XRUN_DEBUG
static void snd_pcm_xrun_debug_read(struct snd_info_entry *entry,
                            struct snd_info_buffer *buffer)
{
      struct snd_pcm_str *pstr = entry->private_data;
      snd_iprintf(buffer, "%d\n", pstr->xrun_debug);
}

static void snd_pcm_xrun_debug_write(struct snd_info_entry *entry,
                             struct snd_info_buffer *buffer)
{
      struct snd_pcm_str *pstr = entry->private_data;
      char line[64];
      if (!snd_info_get_line(buffer, line, sizeof(line)))
            pstr->xrun_debug = simple_strtoul(line, NULL, 10);
}
#endif

static int snd_pcm_stream_proc_init(struct snd_pcm_str *pstr)
{
      struct snd_pcm *pcm = pstr->pcm;
      struct snd_info_entry *entry;
      char name[16];

      sprintf(name, "pcm%i%c", pcm->device, 
            pstr->stream == SNDRV_PCM_STREAM_PLAYBACK ? 'p' : 'c');
      if ((entry = snd_info_create_card_entry(pcm->card, name, pcm->card->proc_root)) == NULL)
            return -ENOMEM;
      entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
      if (snd_info_register(entry) < 0) {
            snd_info_free_entry(entry);
            return -ENOMEM;
      }
      pstr->proc_root = entry;

      if ((entry = snd_info_create_card_entry(pcm->card, "info", pstr->proc_root)) != NULL) {
            snd_info_set_text_ops(entry, pstr, snd_pcm_stream_proc_info_read);
            if (snd_info_register(entry) < 0) {
                  snd_info_free_entry(entry);
                  entry = NULL;
            }
      }
      pstr->proc_info_entry = entry;

#ifdef CONFIG_SND_PCM_XRUN_DEBUG
      if ((entry = snd_info_create_card_entry(pcm->card, "xrun_debug",
                                    pstr->proc_root)) != NULL) {
            entry->c.text.read = snd_pcm_xrun_debug_read;
            entry->c.text.write = snd_pcm_xrun_debug_write;
            entry->mode |= S_IWUSR;
            entry->private_data = pstr;
            if (snd_info_register(entry) < 0) {
                  snd_info_free_entry(entry);
                  entry = NULL;
            }
      }
      pstr->proc_xrun_debug_entry = entry;
#endif
      return 0;
}

static int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr)
{
#ifdef CONFIG_SND_PCM_XRUN_DEBUG
      snd_info_free_entry(pstr->proc_xrun_debug_entry);
      pstr->proc_xrun_debug_entry = NULL;
#endif
      snd_info_free_entry(pstr->proc_info_entry);
      pstr->proc_info_entry = NULL;
      snd_info_free_entry(pstr->proc_root);
      pstr->proc_root = NULL;
      return 0;
}

static int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream)
{
      struct snd_info_entry *entry;
      struct snd_card *card;
      char name[16];

      card = substream->pcm->card;

      sprintf(name, "sub%i", substream->number);
      if ((entry = snd_info_create_card_entry(card, name, substream->pstr->proc_root)) == NULL)
            return -ENOMEM;
      entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
      if (snd_info_register(entry) < 0) {
            snd_info_free_entry(entry);
            return -ENOMEM;
      }
      substream->proc_root = entry;

      if ((entry = snd_info_create_card_entry(card, "info", substream->proc_root)) != NULL) {
            snd_info_set_text_ops(entry, substream,
                              snd_pcm_substream_proc_info_read);
            if (snd_info_register(entry) < 0) {
                  snd_info_free_entry(entry);
                  entry = NULL;
            }
      }
      substream->proc_info_entry = entry;

      if ((entry = snd_info_create_card_entry(card, "hw_params", substream->proc_root)) != NULL) {
            snd_info_set_text_ops(entry, substream,
                              snd_pcm_substream_proc_hw_params_read);
            if (snd_info_register(entry) < 0) {
                  snd_info_free_entry(entry);
                  entry = NULL;
            }
      }
      substream->proc_hw_params_entry = entry;

      if ((entry = snd_info_create_card_entry(card, "sw_params", substream->proc_root)) != NULL) {
            snd_info_set_text_ops(entry, substream,
                              snd_pcm_substream_proc_sw_params_read);
            if (snd_info_register(entry) < 0) {
                  snd_info_free_entry(entry);
                  entry = NULL;
            }
      }
      substream->proc_sw_params_entry = entry;

      if ((entry = snd_info_create_card_entry(card, "status", substream->proc_root)) != NULL) {
            snd_info_set_text_ops(entry, substream,
                              snd_pcm_substream_proc_status_read);
            if (snd_info_register(entry) < 0) {
                  snd_info_free_entry(entry);
                  entry = NULL;
            }
      }
      substream->proc_status_entry = entry;

      return 0;
}

static int snd_pcm_substream_proc_done(struct snd_pcm_substream *substream)
{
      snd_info_free_entry(substream->proc_info_entry);
      substream->proc_info_entry = NULL;
      snd_info_free_entry(substream->proc_hw_params_entry);
      substream->proc_hw_params_entry = NULL;
      snd_info_free_entry(substream->proc_sw_params_entry);
      substream->proc_sw_params_entry = NULL;
      snd_info_free_entry(substream->proc_status_entry);
      substream->proc_status_entry = NULL;
      snd_info_free_entry(substream->proc_root);
      substream->proc_root = NULL;
      return 0;
}
#else /* !CONFIG_SND_VERBOSE_PROCFS */
static inline int snd_pcm_stream_proc_init(struct snd_pcm_str *pstr) { return 0; }
static inline int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr) { return 0; }
static inline int snd_pcm_substream_proc_init(struct snd_pcm_substream *substream) { return 0; }
static inline int snd_pcm_substream_proc_done(struct snd_pcm_substream *substream) { return 0; }
#endif /* CONFIG_SND_VERBOSE_PROCFS */

/**
 * snd_pcm_new_stream - create a new PCM stream
 * @pcm: the pcm instance
 * @stream: the stream direction, SNDRV_PCM_STREAM_XXX
 * @substream_count: the number of substreams
 *
 * Creates a new stream for the pcm.
 * The corresponding stream on the pcm must have been empty before
 * calling this, i.e. zero must be given to the argument of
 * snd_pcm_new().
 *
 * Returns zero if successful, or a negative error code on failure.
 */
int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count)
{
      int idx, err;
      struct snd_pcm_str *pstr = &pcm->streams[stream];
      struct snd_pcm_substream *substream, *prev;

#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
      mutex_init(&pstr->oss.setup_mutex);
#endif
      pstr->stream = stream;
      pstr->pcm = pcm;
      pstr->substream_count = substream_count;
      if (substream_count > 0) {
            err = snd_pcm_stream_proc_init(pstr);
            if (err < 0) {
                  snd_printk(KERN_ERR "Error in snd_pcm_stream_proc_init\n");
                  return err;
            }
      }
      prev = NULL;
      for (idx = 0, prev = NULL; idx < substream_count; idx++) {
            substream = kzalloc(sizeof(*substream), GFP_KERNEL);
            if (substream == NULL) {
                  snd_printk(KERN_ERR "Cannot allocate PCM substream\n");
                  return -ENOMEM;
            }
            substream->pcm = pcm;
            substream->pstr = pstr;
            substream->number = idx;
            substream->stream = stream;
            sprintf(substream->name, "subdevice #%i", idx);
            snprintf(substream->latency_id, sizeof(substream->latency_id),
                   "ALSA-PCM%d-%d%c%d", pcm->card->number, pcm->device,
                   (stream ? 'c' : 'p'), idx);
            substream->buffer_bytes_max = UINT_MAX;
            if (prev == NULL)
                  pstr->substream = substream;
            else
                  prev->next = substream;
            err = snd_pcm_substream_proc_init(substream);
            if (err < 0) {
                  snd_printk(KERN_ERR "Error in snd_pcm_stream_proc_init\n");
                  if (prev == NULL)
                        pstr->substream = NULL;
                  else
                        prev->next = NULL;
                  kfree(substream);
                  return err;
            }
            substream->group = &substream->self_group;
            spin_lock_init(&substream->self_group.lock);
            INIT_LIST_HEAD(&substream->self_group.substreams);
            list_add_tail(&substream->link_list, &substream->self_group.substreams);
            spin_lock_init(&substream->timer_lock);
            atomic_set(&substream->mmap_count, 0);
            prev = substream;
      }
      return 0;
}                       

EXPORT_SYMBOL(snd_pcm_new_stream);

/**
 * snd_pcm_new - create a new PCM instance
 * @card: the card instance
 * @id: the id string
 * @device: the device index (zero based)
 * @playback_count: the number of substreams for playback
 * @capture_count: the number of substreams for capture
 * @rpcm: the pointer to store the new pcm instance
 *
 * Creates a new PCM instance.
 *
 * The pcm operators have to be set afterwards to the new instance
 * via snd_pcm_set_ops().
 *
 * Returns zero if successful, or a negative error code on failure.
 */
int snd_pcm_new(struct snd_card *card, char *id, int device,
            int playback_count, int capture_count,
              struct snd_pcm ** rpcm)
{
      struct snd_pcm *pcm;
      int err;
      static struct snd_device_ops ops = {
            .dev_free = snd_pcm_dev_free,
            .dev_register =   snd_pcm_dev_register,
            .dev_disconnect = snd_pcm_dev_disconnect,
      };

      snd_assert(rpcm != NULL, return -EINVAL);
      *rpcm = NULL;
      snd_assert(card != NULL, return -ENXIO);
      pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
      if (pcm == NULL) {
            snd_printk(KERN_ERR "Cannot allocate PCM\n");
            return -ENOMEM;
      }
      pcm->card = card;
      pcm->device = device;
      if (id)
            strlcpy(pcm->id, id, sizeof(pcm->id));
      if ((err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_PLAYBACK, playback_count)) < 0) {
            snd_pcm_free(pcm);
            return err;
      }
      if ((err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_CAPTURE, capture_count)) < 0) {
            snd_pcm_free(pcm);
            return err;
      }
      mutex_init(&pcm->open_mutex);
      init_waitqueue_head(&pcm->open_wait);
      if ((err = snd_device_new(card, SNDRV_DEV_PCM, pcm, &ops)) < 0) {
            snd_pcm_free(pcm);
            return err;
      }
      *rpcm = pcm;
      return 0;
}

EXPORT_SYMBOL(snd_pcm_new);

static void snd_pcm_free_stream(struct snd_pcm_str * pstr)
{
      struct snd_pcm_substream *substream, *substream_next;
#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
      struct snd_pcm_oss_setup *setup, *setupn;
#endif
      substream = pstr->substream;
      while (substream) {
            substream_next = substream->next;
            snd_pcm_timer_done(substream);
            snd_pcm_substream_proc_done(substream);
            kfree(substream);
            substream = substream_next;
      }
      snd_pcm_stream_proc_done(pstr);
#if defined(CONFIG_SND_PCM_OSS) || defined(CONFIG_SND_PCM_OSS_MODULE)
      for (setup = pstr->oss.setup_list; setup; setup = setupn) {
            setupn = setup->next;
            kfree(setup->task_name);
            kfree(setup);
      }
#endif
}

static int snd_pcm_free(struct snd_pcm *pcm)
{
      struct snd_pcm_notify *notify;

      snd_assert(pcm != NULL, return -ENXIO);
      list_for_each_entry(notify, &snd_pcm_notify_list, list) {
            notify->n_unregister(pcm);
      }
      if (pcm->private_free)
            pcm->private_free(pcm);
      snd_pcm_lib_preallocate_free_for_all(pcm);
      snd_pcm_free_stream(&pcm->streams[SNDRV_PCM_STREAM_PLAYBACK]);
      snd_pcm_free_stream(&pcm->streams[SNDRV_PCM_STREAM_CAPTURE]);
      kfree(pcm);
      return 0;
}

static int snd_pcm_dev_free(struct snd_device *device)
{
      struct snd_pcm *pcm = device->device_data;
      return snd_pcm_free(pcm);
}

static void snd_pcm_tick_timer_func(unsigned long data)
{
      struct snd_pcm_substream *substream = (struct snd_pcm_substream *) data;
      snd_pcm_tick_elapsed(substream);
}

int snd_pcm_attach_substream(struct snd_pcm *pcm, int stream,
                       struct file *file,
                       struct snd_pcm_substream **rsubstream)
{
      struct snd_pcm_str * pstr;
      struct snd_pcm_substream *substream;
      struct snd_pcm_runtime *runtime;
      struct snd_ctl_file *kctl;
      struct snd_card *card;
      int prefer_subdevice = -1;
      size_t size;

      snd_assert(rsubstream != NULL, return -EINVAL);
      *rsubstream = NULL;
      snd_assert(pcm != NULL, return -ENXIO);
      pstr = &pcm->streams[stream];
      if (pstr->substream == NULL || pstr->substream_count == 0)
            return -ENODEV;

      card = pcm->card;
      down_read(&card->controls_rwsem);
      list_for_each_entry(kctl, &card->ctl_files, list) {
            if (kctl->pid == current->pid) {
                  prefer_subdevice = kctl->prefer_pcm_subdevice;
                  if (prefer_subdevice != -1)
                        break;
            }
      }
      up_read(&card->controls_rwsem);

      switch (stream) {
      case SNDRV_PCM_STREAM_PLAYBACK:
            if (pcm->info_flags & SNDRV_PCM_INFO_HALF_DUPLEX) {
                  for (substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream; substream; substream = substream->next) {
                        if (SUBSTREAM_BUSY(substream))
                              return -EAGAIN;
                  }
            }
            break;
      case SNDRV_PCM_STREAM_CAPTURE:
            if (pcm->info_flags & SNDRV_PCM_INFO_HALF_DUPLEX) {
                  for (substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream; substream; substream = substream->next) {
                        if (SUBSTREAM_BUSY(substream))
                              return -EAGAIN;
                  }
            }
            break;
      default:
            return -EINVAL;
      }

      if (file->f_flags & O_APPEND) {
            if (prefer_subdevice < 0) {
                  if (pstr->substream_count > 1)
                        return -EINVAL; /* must be unique */
                  substream = pstr->substream;
            } else {
                  for (substream = pstr->substream; substream;
                       substream = substream->next)
                        if (substream->number == prefer_subdevice)
                              break;
            }
            if (! substream)
                  return -ENODEV;
            if (! SUBSTREAM_BUSY(substream))
                  return -EBADFD;
            substream->ref_count++;
            *rsubstream = substream;
            return 0;
      }

      if (prefer_subdevice >= 0) {
            for (substream = pstr->substream; substream; substream = substream->next)
                  if (!SUBSTREAM_BUSY(substream) && substream->number == prefer_subdevice)
                        goto __ok;
      }
      for (substream = pstr->substream; substream; substream = substream->next)
            if (!SUBSTREAM_BUSY(substream))
                  break;
      __ok:
      if (substream == NULL)
            return -EAGAIN;

      runtime = kzalloc(sizeof(*runtime), GFP_KERNEL);
      if (runtime == NULL)
            return -ENOMEM;

      size = PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status));
      runtime->status = snd_malloc_pages(size, GFP_KERNEL);
      if (runtime->status == NULL) {
            kfree(runtime);
            return -ENOMEM;
      }
      memset((void*)runtime->status, 0, size);

      size = PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control));
      runtime->control = snd_malloc_pages(size, GFP_KERNEL);
      if (runtime->control == NULL) {
            snd_free_pages((void*)runtime->status,
                         PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
            kfree(runtime);
            return -ENOMEM;
      }
      memset((void*)runtime->control, 0, size);

      init_waitqueue_head(&runtime->sleep);
      init_timer(&runtime->tick_timer);
      runtime->tick_timer.function = snd_pcm_tick_timer_func;
      runtime->tick_timer.data = (unsigned long) substream;

      runtime->status->state = SNDRV_PCM_STATE_OPEN;

      substream->runtime = runtime;
      substream->private_data = pcm->private_data;
      substream->ref_count = 1;
      substream->f_flags = file->f_flags;
      pstr->substream_opened++;
      *rsubstream = substream;
      return 0;
}

void snd_pcm_detach_substream(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime;

      runtime = substream->runtime;
      snd_assert(runtime != NULL, return);
      if (runtime->private_free != NULL)
            runtime->private_free(runtime);
      snd_free_pages((void*)runtime->status,
                   PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
      snd_free_pages((void*)runtime->control,
                   PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control)));
      kfree(runtime->hw_constraints.rules);
      kfree(runtime);
      substream->runtime = NULL;
      substream->pstr->substream_opened--;
}

static ssize_t show_pcm_class(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
      struct snd_pcm *pcm;
      const char *str;
      static const char *strs[SNDRV_PCM_CLASS_LAST + 1] = {
            [SNDRV_PCM_CLASS_GENERIC] = "generic",
            [SNDRV_PCM_CLASS_MULTI] = "multi",
            [SNDRV_PCM_CLASS_MODEM] = "modem",
            [SNDRV_PCM_CLASS_DIGITIZER] = "digitizer",
      };

      if (! (pcm = dev_get_drvdata(dev)) ||
          pcm->dev_class > SNDRV_PCM_CLASS_LAST)
            str = "none";
      else
            str = strs[pcm->dev_class];
        return snprintf(buf, PAGE_SIZE, "%s\n", str);
}

static struct device_attribute pcm_attrs =
      __ATTR(pcm_class, S_IRUGO, show_pcm_class, NULL);

static int snd_pcm_dev_register(struct snd_device *device)
{
      int cidx, err;
      struct snd_pcm_substream *substream;
      struct snd_pcm_notify *notify;
      char str[16];
      struct snd_pcm *pcm = device->device_data;
      struct device *dev;

      snd_assert(pcm != NULL && device != NULL, return -ENXIO);
      mutex_lock(&register_mutex);
      if (snd_pcm_search(pcm->card, pcm->device)) {
            mutex_unlock(&register_mutex);
            return -EBUSY;
      }
      list_add_tail(&pcm->list, &snd_pcm_devices);
      for (cidx = 0; cidx < 2; cidx++) {
            int devtype = -1;
            if (pcm->streams[cidx].substream == NULL)
                  continue;
            switch (cidx) {
            case SNDRV_PCM_STREAM_PLAYBACK:
                  sprintf(str, "pcmC%iD%ip", pcm->card->number, pcm->device);
                  devtype = SNDRV_DEVICE_TYPE_PCM_PLAYBACK;
                  break;
            case SNDRV_PCM_STREAM_CAPTURE:
                  sprintf(str, "pcmC%iD%ic", pcm->card->number, pcm->device);
                  devtype = SNDRV_DEVICE_TYPE_PCM_CAPTURE;
                  break;
            }
            /* device pointer to use, pcm->dev takes precedence if
             * it is assigned, otherwise fall back to card's device
             * if possible */
            dev = pcm->dev;
            if (!dev)
                  dev = snd_card_get_device_link(pcm->card);
            /* register pcm */
            err = snd_register_device_for_dev(devtype, pcm->card,
                                      pcm->device,
                                      &snd_pcm_f_ops[cidx],
                                      pcm, str, dev);
            if (err < 0) {
                  list_del(&pcm->list);
                  mutex_unlock(&register_mutex);
                  return err;
            }
            snd_add_device_sysfs_file(devtype, pcm->card, pcm->device,
                                &pcm_attrs);
            for (substream = pcm->streams[cidx].substream; substream; substream = substream->next)
                  snd_pcm_timer_init(substream);
      }

      list_for_each_entry(notify, &snd_pcm_notify_list, list)
            notify->n_register(pcm);

      mutex_unlock(&register_mutex);
      return 0;
}

static int snd_pcm_dev_disconnect(struct snd_device *device)
{
      struct snd_pcm *pcm = device->device_data;
      struct snd_pcm_notify *notify;
      struct snd_pcm_substream *substream;
      int cidx, devtype;

      mutex_lock(&register_mutex);
      if (list_empty(&pcm->list))
            goto unlock;

      list_del_init(&pcm->list);
      for (cidx = 0; cidx < 2; cidx++)
            for (substream = pcm->streams[cidx].substream; substream; substream = substream->next)
                  if (substream->runtime)
                        substream->runtime->status->state = SNDRV_PCM_STATE_DISCONNECTED;
      list_for_each_entry(notify, &snd_pcm_notify_list, list) {
            notify->n_disconnect(pcm);
      }
      for (cidx = 0; cidx < 2; cidx++) {
            devtype = -1;
            switch (cidx) {
            case SNDRV_PCM_STREAM_PLAYBACK:
                  devtype = SNDRV_DEVICE_TYPE_PCM_PLAYBACK;
                  break;
            case SNDRV_PCM_STREAM_CAPTURE:
                  devtype = SNDRV_DEVICE_TYPE_PCM_CAPTURE;
                  break;
            }
            snd_unregister_device(devtype, pcm->card, pcm->device);
      }
 unlock:
      mutex_unlock(&register_mutex);
      return 0;
}

int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree)
{
      struct snd_pcm *pcm;

      snd_assert(notify != NULL &&
               notify->n_register != NULL &&
               notify->n_unregister != NULL &&
               notify->n_disconnect, return -EINVAL);
      mutex_lock(&register_mutex);
      if (nfree) {
            list_del(&notify->list);
            list_for_each_entry(pcm, &snd_pcm_devices, list)
                  notify->n_unregister(pcm);
      } else {
            list_add_tail(&notify->list, &snd_pcm_notify_list);
            list_for_each_entry(pcm, &snd_pcm_devices, list)
                  notify->n_register(pcm);
      }
      mutex_unlock(&register_mutex);
      return 0;
}

EXPORT_SYMBOL(snd_pcm_notify);

#ifdef CONFIG_PROC_FS
/*
 *  Info interface
 */

static void snd_pcm_proc_read(struct snd_info_entry *entry,
                        struct snd_info_buffer *buffer)
{
      struct snd_pcm *pcm;

      mutex_lock(&register_mutex);
      list_for_each_entry(pcm, &snd_pcm_devices, list) {
            snd_iprintf(buffer, "%02i-%02i: %s : %s",
                      pcm->card->number, pcm->device, pcm->id, pcm->name);
            if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream)
                  snd_iprintf(buffer, " : playback %i",
                            pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream_count);
            if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream)
                  snd_iprintf(buffer, " : capture %i",
                            pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count);
            snd_iprintf(buffer, "\n");
      }
      mutex_unlock(&register_mutex);
}

static struct snd_info_entry *snd_pcm_proc_entry;

static void snd_pcm_proc_init(void)
{
      struct snd_info_entry *entry;

      if ((entry = snd_info_create_module_entry(THIS_MODULE, "pcm", NULL)) != NULL) {
            snd_info_set_text_ops(entry, NULL, snd_pcm_proc_read);
            if (snd_info_register(entry) < 0) {
                  snd_info_free_entry(entry);
                  entry = NULL;
            }
      }
      snd_pcm_proc_entry = entry;
}

static void snd_pcm_proc_done(void)
{
      snd_info_free_entry(snd_pcm_proc_entry);
}

#else /* !CONFIG_PROC_FS */
#define snd_pcm_proc_init()
#define snd_pcm_proc_done()
#endif /* CONFIG_PROC_FS */


/*
 *  ENTRY functions
 */

static int __init alsa_pcm_init(void)
{
      snd_ctl_register_ioctl(snd_pcm_control_ioctl);
      snd_ctl_register_ioctl_compat(snd_pcm_control_ioctl);
      snd_pcm_proc_init();
      return 0;
}

static void __exit alsa_pcm_exit(void)
{
      snd_ctl_unregister_ioctl(snd_pcm_control_ioctl);
      snd_ctl_unregister_ioctl_compat(snd_pcm_control_ioctl);
      snd_pcm_proc_done();
}

module_init(alsa_pcm_init)
module_exit(alsa_pcm_exit)

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