Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1247 insertions, 0 deletions

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
new file mode 100644
index 000000000..2415a3c3a
--- /dev/null
+++ b/sound/core/pcm.c
@@ -0,0 +1,1247 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Digital Audio (PCM) abstract layer
+ *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/time.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <linux/nospec.h>
+#include <sound/core.h>
+#include <sound/minors.h>
+#include <sound/pcm.h>
+#include <sound/timer.h>
+#include <sound/control.h>
+#include <sound/info.h>
+
+#include "pcm_local.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 DEFINE_MUTEX(register_mutex);
+#if IS_ENABLED(CONFIG_SND_PCM_OSS)
+static LIST_HEAD(snd_pcm_notify_list);
+#endif
+
+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_get(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_next(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->device;
+		else if (pcm->card->number > card->number)
+			return -1;
+	}
+	return -1;
+}
+
+static int snd_pcm_add(struct snd_pcm *newpcm)
+{
+	struct snd_pcm *pcm;
+
+	if (newpcm->internal)
+		return 0;
+
+	list_for_each_entry(pcm, &snd_pcm_devices, list) {
+		if (pcm->card == newpcm->card && pcm->device == newpcm->device)
+			return -EBUSY;
+		if (pcm->card->number > newpcm->card->number ||
+				(pcm->card == newpcm->card &&
+				pcm->device > newpcm->device)) {
+			list_add(&newpcm->list, pcm->list.prev);
+			return 0;
+		}
+	}
+	list_add_tail(&newpcm->list, &snd_pcm_devices);
+	return 0;
+}
+
+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 = snd_pcm_next(card, device);
+			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;
+			stream = array_index_nospec(stream, 2);
+			if (get_user(subdevice, &info->subdevice))
+				return -EFAULT;
+			mutex_lock(&register_mutex);
+			pcm = snd_pcm_get(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;
+			}
+			mutex_lock(&pcm->open_mutex);
+			err = snd_pcm_info_user(substream, info);
+			mutex_unlock(&pcm->open_mutex);
+		_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->preferred_subdevice[SND_CTL_SUBDEV_PCM] = val;
+			return 0;
+		}
+	}
+	return -ENOIOCTLCMD;
+}
+
+#define FORMAT(v) [SNDRV_PCM_FORMAT_##v] = #v
+
+static const char * const 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),
+	FORMAT(G723_24),
+	FORMAT(G723_24_1B),
+	FORMAT(G723_40),
+	FORMAT(G723_40_1B),
+	FORMAT(DSD_U8),
+	FORMAT(DSD_U16_LE),
+	FORMAT(DSD_U32_LE),
+	FORMAT(DSD_U16_BE),
+	FORMAT(DSD_U32_BE),
+};
+
+/**
+ * snd_pcm_format_name - Return a name string for the given PCM format
+ * @format: PCM format
+ *
+ * Return: the format name string
+ */
+const char *snd_pcm_format_name(snd_pcm_format_t format)
+{
+	if ((__force unsigned int)format >= ARRAY_SIZE(snd_pcm_format_names))
+		return "Unknown";
+	return snd_pcm_format_names[(__force unsigned int)format];
+}
+EXPORT_SYMBOL_GPL(snd_pcm_format_name);
+
+#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 SUBFORMAT(v) [SNDRV_PCM_SUBFORMAT_##v] = #v 
+
+static const char * const snd_pcm_stream_names[] = {
+	STREAM(PLAYBACK),
+	STREAM(CAPTURE),
+};
+
+static const char * const snd_pcm_state_names[] = {
+	STATE(OPEN),
+	STATE(SETUP),
+	STATE(PREPARED),
+	STATE(RUNNING),
+	STATE(XRUN),
+	STATE(DRAINING),
+	STATE(PAUSED),
+	STATE(SUSPENDED),
+	STATE(DISCONNECTED),
+};
+
+static const char * const snd_pcm_access_names[] = {
+	ACCESS(MMAP_INTERLEAVED), 
+	ACCESS(MMAP_NONINTERLEAVED),
+	ACCESS(MMAP_COMPLEX),
+	ACCESS(RW_INTERLEAVED),
+	ACCESS(RW_NONINTERLEAVED),
+};
+
+static const char * const snd_pcm_subformat_names[] = {
+	SUBFORMAT(STD), 
+};
+
+static const char * const snd_pcm_tstamp_mode_names[] = {
+	TSTAMP(NONE),
+	TSTAMP(ENABLE),
+};
+
+static const char *snd_pcm_stream_name(int stream)
+{
+	return snd_pcm_stream_names[stream];
+}
+
+static const char *snd_pcm_access_name(snd_pcm_access_t access)
+{
+	return snd_pcm_access_names[(__force int)access];
+}
+
+static const char *snd_pcm_subformat_name(snd_pcm_subformat_t subformat)
+{
+	return snd_pcm_subformat_names[(__force int)subformat];
+}
+
+static const char *snd_pcm_tstamp_mode_name(int mode)
+{
+	return snd_pcm_tstamp_mode_names[mode];
+}
+
+static const char *snd_pcm_state_name(snd_pcm_state_t state)
+{
+	return snd_pcm_state_names[(__force int)state];
+}
+
+#if IS_ENABLED(CONFIG_SND_PCM_OSS)
+#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)
+		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(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;
+
+	mutex_lock(&substream->pcm->open_mutex);
+	runtime = substream->runtime;
+	if (!runtime) {
+		snd_iprintf(buffer, "closed\n");
+		goto unlock;
+	}
+	if (runtime->state == SNDRV_PCM_STATE_OPEN) {
+		snd_iprintf(buffer, "no setup\n");
+		goto unlock;
+	}
+	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);	
+#if IS_ENABLED(CONFIG_SND_PCM_OSS)
+	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
+ unlock:
+	mutex_unlock(&substream->pcm->open_mutex);
+}
+
+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;
+
+	mutex_lock(&substream->pcm->open_mutex);
+	runtime = substream->runtime;
+	if (!runtime) {
+		snd_iprintf(buffer, "closed\n");
+		goto unlock;
+	}
+	if (runtime->state == SNDRV_PCM_STATE_OPEN) {
+		snd_iprintf(buffer, "no setup\n");
+		goto unlock;
+	}
+	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, "avail_min: %lu\n", runtime->control->avail_min);
+	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);
+ unlock:
+	mutex_unlock(&substream->pcm->open_mutex);
+}
+
+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;
+	struct snd_pcm_status64 status;
+	int err;
+
+	mutex_lock(&substream->pcm->open_mutex);
+	runtime = substream->runtime;
+	if (!runtime) {
+		snd_iprintf(buffer, "closed\n");
+		goto unlock;
+	}
+	memset(&status, 0, sizeof(status));
+	err = snd_pcm_status64(substream, &status);
+	if (err < 0) {
+		snd_iprintf(buffer, "error %d\n", err);
+		goto unlock;
+	}
+	snd_iprintf(buffer, "state: %s\n", snd_pcm_state_name(status.state));
+	snd_iprintf(buffer, "owner_pid   : %d\n", pid_vnr(substream->pid));
+	snd_iprintf(buffer, "trigger_time: %lld.%09lld\n",
+		status.trigger_tstamp_sec, status.trigger_tstamp_nsec);
+	snd_iprintf(buffer, "tstamp      : %lld.%09lld\n",
+		status.tstamp_sec, status.tstamp_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);
+ unlock:
+	mutex_unlock(&substream->pcm->open_mutex);
+}
+
+#ifdef CONFIG_SND_PCM_XRUN_DEBUG
+static void snd_pcm_xrun_injection_write(struct snd_info_entry *entry,
+					 struct snd_info_buffer *buffer)
+{
+	struct snd_pcm_substream *substream = entry->private_data;
+
+	snd_pcm_stop_xrun(substream);
+}
+
+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');
+	entry = snd_info_create_card_entry(pcm->card, name,
+					   pcm->card->proc_root);
+	if (!entry)
+		return -ENOMEM;
+	entry->mode = S_IFDIR | 0555;
+	pstr->proc_root = entry;
+	entry = snd_info_create_card_entry(pcm->card, "info", pstr->proc_root);
+	if (entry)
+		snd_info_set_text_ops(entry, pstr, snd_pcm_stream_proc_info_read);
+#ifdef CONFIG_SND_PCM_XRUN_DEBUG
+	entry = snd_info_create_card_entry(pcm->card, "xrun_debug",
+					   pstr->proc_root);
+	if (entry) {
+		snd_info_set_text_ops(entry, pstr, snd_pcm_xrun_debug_read);
+		entry->c.text.write = snd_pcm_xrun_debug_write;
+		entry->mode |= 0200;
+	}
+#endif
+	return 0;
+}
+
+static int snd_pcm_stream_proc_done(struct snd_pcm_str *pstr)
+{
+	snd_info_free_entry(pstr->proc_root);
+	pstr->proc_root = NULL;
+	return 0;
+}
+
+static struct snd_info_entry *
+create_substream_info_entry(struct snd_pcm_substream *substream,
+			    const char *name,
+			    void (*read)(struct snd_info_entry *,
+					 struct snd_info_buffer *))
+{
+	struct snd_info_entry *entry;
+
+	entry = snd_info_create_card_entry(substream->pcm->card, name,
+					   substream->proc_root);
+	if (entry)
+		snd_info_set_text_ops(entry, substream, read);
+	return entry;
+}
+
+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);
+	entry = snd_info_create_card_entry(card, name,
+					   substream->pstr->proc_root);
+	if (!entry)
+		return -ENOMEM;
+	entry->mode = S_IFDIR | 0555;
+	substream->proc_root = entry;
+
+	create_substream_info_entry(substream, "info",
+				    snd_pcm_substream_proc_info_read);
+	create_substream_info_entry(substream, "hw_params",
+				    snd_pcm_substream_proc_hw_params_read);
+	create_substream_info_entry(substream, "sw_params",
+				    snd_pcm_substream_proc_sw_params_read);
+	create_substream_info_entry(substream, "status",
+				    snd_pcm_substream_proc_status_read);
+
+#ifdef CONFIG_SND_PCM_XRUN_DEBUG
+	entry = create_substream_info_entry(substream, "xrun_injection", NULL);
+	if (entry) {
+		entry->c.text.write = snd_pcm_xrun_injection_write;
+		entry->mode = S_IFREG | 0200;
+	}
+#endif /* CONFIG_SND_PCM_XRUN_DEBUG */
+
+	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; }
+#endif /* CONFIG_SND_VERBOSE_PROCFS */
+
+static const struct attribute_group *pcm_dev_attr_groups[];
+
+/*
+ * PM callbacks: we need to deal only with suspend here, as the resume is
+ * triggered either from user-space or the driver's resume callback
+ */
+#ifdef CONFIG_PM_SLEEP
+static int do_pcm_suspend(struct device *dev)
+{
+	struct snd_pcm_str *pstr = container_of(dev, struct snd_pcm_str, dev);
+
+	if (!pstr->pcm->no_device_suspend)
+		snd_pcm_suspend_all(pstr->pcm);
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops pcm_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(do_pcm_suspend, NULL)
+};
+
+/* device type for PCM -- basically only for passing PM callbacks */
+static const struct device_type pcm_dev_type = {
+	.name = "pcm",
+	.pm = &pcm_dev_pm_ops,
+};
+
+/**
+ * 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().
+ *
+ * Return: 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 IS_ENABLED(CONFIG_SND_PCM_OSS)
+	mutex_init(&pstr->oss.setup_mutex);
+#endif
+	pstr->stream = stream;
+	pstr->pcm = pcm;
+	pstr->substream_count = substream_count;
+	if (!substream_count)
+		return 0;
+
+	snd_device_initialize(&pstr->dev, pcm->card);
+	pstr->dev.groups = pcm_dev_attr_groups;
+	pstr->dev.type = &pcm_dev_type;
+	dev_set_name(&pstr->dev, "pcmC%iD%i%c", pcm->card->number, pcm->device,
+		     stream == SNDRV_PCM_STREAM_PLAYBACK ? 'p' : 'c');
+
+	if (!pcm->internal) {
+		err = snd_pcm_stream_proc_init(pstr);
+		if (err < 0) {
+			pcm_err(pcm, "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)
+			return -ENOMEM;
+		substream->pcm = pcm;
+		substream->pstr = pstr;
+		substream->number = idx;
+		substream->stream = stream;
+		sprintf(substream->name, "subdevice #%i", idx);
+		substream->buffer_bytes_max = UINT_MAX;
+		if (prev == NULL)
+			pstr->substream = substream;
+		else
+			prev->next = substream;
+
+		if (!pcm->internal) {
+			err = snd_pcm_substream_proc_init(substream);
+			if (err < 0) {
+				pcm_err(pcm,
+					"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;
+		snd_pcm_group_init(&substream->self_group);
+		list_add_tail(&substream->link_list, &substream->self_group.substreams);
+		atomic_set(&substream->mmap_count, 0);
+		prev = substream;
+	}
+	return 0;
+}				
+EXPORT_SYMBOL(snd_pcm_new_stream);
+
+static int _snd_pcm_new(struct snd_card *card, const char *id, int device,
+		int playback_count, int capture_count, bool internal,
+		struct snd_pcm **rpcm)
+{
+	struct snd_pcm *pcm;
+	int err;
+	static const struct snd_device_ops ops = {
+		.dev_free = snd_pcm_dev_free,
+		.dev_register =	snd_pcm_dev_register,
+		.dev_disconnect = snd_pcm_dev_disconnect,
+	};
+	static const struct snd_device_ops internal_ops = {
+		.dev_free = snd_pcm_dev_free,
+	};
+
+	if (snd_BUG_ON(!card))
+		return -ENXIO;
+	if (rpcm)
+		*rpcm = NULL;
+	pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
+	if (!pcm)
+		return -ENOMEM;
+	pcm->card = card;
+	pcm->device = device;
+	pcm->internal = internal;
+	mutex_init(&pcm->open_mutex);
+	init_waitqueue_head(&pcm->open_wait);
+	INIT_LIST_HEAD(&pcm->list);
+	if (id)
+		strscpy(pcm->id, id, sizeof(pcm->id));
+
+	err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_PLAYBACK,
+				 playback_count);
+	if (err < 0)
+		goto free_pcm;
+
+	err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_CAPTURE, capture_count);
+	if (err < 0)
+		goto free_pcm;
+
+	err = snd_device_new(card, SNDRV_DEV_PCM, pcm,
+			     internal ? &internal_ops : &ops);
+	if (err < 0)
+		goto free_pcm;
+
+	if (rpcm)
+		*rpcm = pcm;
+	return 0;
+
+free_pcm:
+	snd_pcm_free(pcm);
+	return err;
+}
+
+/**
+ * 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().
+ *
+ * Return: Zero if successful, or a negative error code on failure.
+ */
+int snd_pcm_new(struct snd_card *card, const char *id, int device,
+		int playback_count, int capture_count, struct snd_pcm **rpcm)
+{
+	return _snd_pcm_new(card, id, device, playback_count, capture_count,
+			false, rpcm);
+}
+EXPORT_SYMBOL(snd_pcm_new);
+
+/**
+ * snd_pcm_new_internal - create a new internal PCM instance
+ * @card: the card instance
+ * @id: the id string
+ * @device: the device index (zero based - shared with normal PCMs)
+ * @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 internal PCM instance with no userspace device or procfs
+ * entries. This is used by ASoC Back End PCMs in order to create a PCM that
+ * will only be used internally by kernel drivers. i.e. it cannot be opened
+ * by userspace. It provides existing ASoC components drivers with a substream
+ * and access to any private data.
+ *
+ * The pcm operators have to be set afterwards to the new instance
+ * via snd_pcm_set_ops().
+ *
+ * Return: Zero if successful, or a negative error code on failure.
+ */
+int snd_pcm_new_internal(struct snd_card *card, const char *id, int device,
+	int playback_count, int capture_count,
+	struct snd_pcm **rpcm)
+{
+	return _snd_pcm_new(card, id, device, playback_count, capture_count,
+			true, rpcm);
+}
+EXPORT_SYMBOL(snd_pcm_new_internal);
+
+static void free_chmap(struct snd_pcm_str *pstr)
+{
+	if (pstr->chmap_kctl) {
+		struct snd_card *card = pstr->pcm->card;
+
+		down_write(&card->controls_rwsem);
+		snd_ctl_remove(card, pstr->chmap_kctl);
+		up_write(&card->controls_rwsem);
+		pstr->chmap_kctl = NULL;
+	}
+}
+
+static void snd_pcm_free_stream(struct snd_pcm_str * pstr)
+{
+	struct snd_pcm_substream *substream, *substream_next;
+#if IS_ENABLED(CONFIG_SND_PCM_OSS)
+	struct snd_pcm_oss_setup *setup, *setupn;
+#endif
+
+	/* free all proc files under the stream */
+	snd_pcm_stream_proc_done(pstr);
+
+	substream = pstr->substream;
+	while (substream) {
+		substream_next = substream->next;
+		snd_pcm_timer_done(substream);
+		kfree(substream);
+		substream = substream_next;
+	}
+#if IS_ENABLED(CONFIG_SND_PCM_OSS)
+	for (setup = pstr->oss.setup_list; setup; setup = setupn) {
+		setupn = setup->next;
+		kfree(setup->task_name);
+		kfree(setup);
+	}
+#endif
+	free_chmap(pstr);
+	if (pstr->substream_count)
+		put_device(&pstr->dev);
+}
+
+#if IS_ENABLED(CONFIG_SND_PCM_OSS)
+#define pcm_call_notify(pcm, call)					\
+	do {								\
+		struct snd_pcm_notify *_notify;				\
+		list_for_each_entry(_notify, &snd_pcm_notify_list, list) \
+			_notify->call(pcm);				\
+	} while (0)
+#else
+#define pcm_call_notify(pcm, call) do {} while (0)
+#endif
+
+static int snd_pcm_free(struct snd_pcm *pcm)
+{
+	if (!pcm)
+		return 0;
+	if (!pcm->internal)
+		pcm_call_notify(pcm, n_unregister);
+	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);
+}
+
+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_card *card;
+	int prefer_subdevice;
+	size_t size;
+
+	if (snd_BUG_ON(!pcm || !rsubstream))
+		return -ENXIO;
+	if (snd_BUG_ON(stream != SNDRV_PCM_STREAM_PLAYBACK &&
+		       stream != SNDRV_PCM_STREAM_CAPTURE))
+		return -EINVAL;
+	*rsubstream = NULL;
+	pstr = &pcm->streams[stream];
+	if (pstr->substream == NULL || pstr->substream_count == 0)
+		return -ENODEV;
+
+	card = pcm->card;
+	prefer_subdevice = snd_ctl_get_preferred_subdevice(card, SND_CTL_SUBDEV_PCM);
+
+	if (pcm->info_flags & SNDRV_PCM_INFO_HALF_DUPLEX) {
+		int opposite = !stream;
+
+		for (substream = pcm->streams[opposite].substream; substream;
+		     substream = substream->next) {
+			if (SUBSTREAM_BUSY(substream))
+				return -EAGAIN;
+		}
+	}
+
+	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;
+	}
+
+	for (substream = pstr->substream; substream; substream = substream->next) {
+		if (!SUBSTREAM_BUSY(substream) &&
+		    (prefer_subdevice == -1 ||
+		     substream->number == prefer_subdevice))
+			break;
+	}
+	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 = alloc_pages_exact(size, GFP_KERNEL);
+	if (runtime->status == NULL) {
+		kfree(runtime);
+		return -ENOMEM;
+	}
+	memset(runtime->status, 0, size);
+
+	size = PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control));
+	runtime->control = alloc_pages_exact(size, GFP_KERNEL);
+	if (runtime->control == NULL) {
+		free_pages_exact(runtime->status,
+			       PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
+		kfree(runtime);
+		return -ENOMEM;
+	}
+	memset(runtime->control, 0, size);
+
+	init_waitqueue_head(&runtime->sleep);
+	init_waitqueue_head(&runtime->tsleep);
+
+	__snd_pcm_set_state(runtime, SNDRV_PCM_STATE_OPEN);
+	mutex_init(&runtime->buffer_mutex);
+	atomic_set(&runtime->buffer_accessing, 0);
+
+	substream->runtime = runtime;
+	substream->private_data = pcm->private_data;
+	substream->ref_count = 1;
+	substream->f_flags = file->f_flags;
+	substream->pid = get_pid(task_pid(current));
+	pstr->substream_opened++;
+	*rsubstream = substream;
+	return 0;
+}
+
+void snd_pcm_detach_substream(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime;
+
+	if (PCM_RUNTIME_CHECK(substream))
+		return;
+	runtime = substream->runtime;
+	if (runtime->private_free != NULL)
+		runtime->private_free(runtime);
+	free_pages_exact(runtime->status,
+		       PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)));
+	free_pages_exact(runtime->control,
+		       PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control)));
+	kfree(runtime->hw_constraints.rules);
+	/* Avoid concurrent access to runtime via PCM timer interface */
+	if (substream->timer) {
+		spin_lock_irq(&substream->timer->lock);
+		substream->runtime = NULL;
+		spin_unlock_irq(&substream->timer->lock);
+	} else {
+		substream->runtime = NULL;
+	}
+	mutex_destroy(&runtime->buffer_mutex);
+	snd_fasync_free(runtime->fasync);
+	kfree(runtime);
+	put_pid(substream->pid);
+	substream->pid = NULL;
+	substream->pstr->substream_opened--;
+}
+
+static ssize_t pcm_class_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct snd_pcm_str *pstr = container_of(dev, struct snd_pcm_str, dev);
+	struct snd_pcm *pcm = pstr->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_class > SNDRV_PCM_CLASS_LAST)
+		str = "none";
+	else
+		str = strs[pcm->dev_class];
+	return sysfs_emit(buf, "%s\n", str);
+}
+
+static DEVICE_ATTR_RO(pcm_class);
+static struct attribute *pcm_dev_attrs[] = {
+	&dev_attr_pcm_class.attr,
+	NULL
+};
+
+static const struct attribute_group pcm_dev_attr_group = {
+	.attrs	= pcm_dev_attrs,
+};
+
+static const struct attribute_group *pcm_dev_attr_groups[] = {
+	&pcm_dev_attr_group,
+	NULL
+};
+
+static int snd_pcm_dev_register(struct snd_device *device)
+{
+	int cidx, err;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm *pcm;
+
+	if (snd_BUG_ON(!device || !device->device_data))
+		return -ENXIO;
+	pcm = device->device_data;
+
+	mutex_lock(&register_mutex);
+	err = snd_pcm_add(pcm);
+	if (err)
+		goto unlock;
+	for (cidx = 0; cidx < 2; cidx++) {
+		int devtype = -1;
+		if (pcm->streams[cidx].substream == NULL)
+			continue;
+		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;
+		}
+		/* register pcm */
+		err = snd_register_device(devtype, pcm->card, pcm->device,
+					  &snd_pcm_f_ops[cidx], pcm,
+					  &pcm->streams[cidx].dev);
+		if (err < 0) {
+			list_del_init(&pcm->list);
+			goto unlock;
+		}
+
+		for (substream = pcm->streams[cidx].substream; substream; substream = substream->next)
+			snd_pcm_timer_init(substream);
+	}
+
+	pcm_call_notify(pcm, n_register);
+
+ unlock:
+	mutex_unlock(&register_mutex);
+	return err;
+}
+
+static int snd_pcm_dev_disconnect(struct snd_device *device)
+{
+	struct snd_pcm *pcm = device->device_data;
+	struct snd_pcm_substream *substream;
+	int cidx;
+
+	mutex_lock(&register_mutex);
+	mutex_lock(&pcm->open_mutex);
+	wake_up(&pcm->open_wait);
+	list_del_init(&pcm->list);
+
+	for_each_pcm_substream(pcm, cidx, substream) {
+		snd_pcm_stream_lock_irq(substream);
+		if (substream->runtime) {
+			if (snd_pcm_running(substream))
+				snd_pcm_stop(substream, SNDRV_PCM_STATE_DISCONNECTED);
+			/* to be sure, set the state unconditionally */
+			__snd_pcm_set_state(substream->runtime,
+					    SNDRV_PCM_STATE_DISCONNECTED);
+			wake_up(&substream->runtime->sleep);
+			wake_up(&substream->runtime->tsleep);
+		}
+		snd_pcm_stream_unlock_irq(substream);
+	}
+
+	for_each_pcm_substream(pcm, cidx, substream)
+		snd_pcm_sync_stop(substream, false);
+
+	pcm_call_notify(pcm, n_disconnect);
+	for (cidx = 0; cidx < 2; cidx++) {
+		snd_unregister_device(&pcm->streams[cidx].dev);
+		free_chmap(&pcm->streams[cidx]);
+	}
+	mutex_unlock(&pcm->open_mutex);
+	mutex_unlock(&register_mutex);
+	return 0;
+}
+
+#if IS_ENABLED(CONFIG_SND_PCM_OSS)
+/**
+ * snd_pcm_notify - Add/remove the notify list
+ * @notify: PCM notify list
+ * @nfree: 0 = register, 1 = unregister
+ *
+ * This adds the given notifier to the global list so that the callback is
+ * called for each registered PCM devices.  This exists only for PCM OSS
+ * emulation, so far.
+ *
+ * Return: zero if successful, or a negative error code
+ */
+int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree)
+{
+	struct snd_pcm *pcm;
+
+	if (snd_BUG_ON(!notify ||
+		       !notify->n_register ||
+		       !notify->n_unregister ||
+		       !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);
+#endif /* CONFIG_SND_PCM_OSS */
+
+#ifdef CONFIG_SND_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;
+
+	entry = snd_info_create_module_entry(THIS_MODULE, "pcm", NULL);
+	if (entry) {
+		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_SND_PROC_FS */
+#define snd_pcm_proc_init()
+#define snd_pcm_proc_done()
+#endif /* CONFIG_SND_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)