Adding upstream version 4.19.249.upstream/4.19.249upstream

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

1 files changed, 3755 insertions, 0 deletions

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
new file mode 100644
index 000000000..9862b60bf
--- /dev/null
+++ b/sound/core/pcm_native.c
@@ -0,0 +1,3755 @@
+/*
+ *  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 <linux/mm.h>
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+#include <linux/time.h>
+#include <linux/pm_qos.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+#include <sound/core.h>
+#include <sound/control.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/timer.h>
+#include <sound/minors.h>
+#include <linux/uio.h>
+#include <linux/delay.h>
+
+#include "pcm_local.h"
+
+#ifdef CONFIG_SND_DEBUG
+#define CREATE_TRACE_POINTS
+#include "pcm_param_trace.h"
+#else
+#define trace_hw_mask_param_enabled()		0
+#define trace_hw_interval_param_enabled()	0
+#define trace_hw_mask_param(substream, type, index, prev, curr)
+#define trace_hw_interval_param(substream, type, index, prev, curr)
+#endif
+
+/*
+ *  Compatibility
+ */
+
+struct snd_pcm_hw_params_old {
+	unsigned int flags;
+	unsigned int masks[SNDRV_PCM_HW_PARAM_SUBFORMAT -
+			   SNDRV_PCM_HW_PARAM_ACCESS + 1];
+	struct snd_interval intervals[SNDRV_PCM_HW_PARAM_TICK_TIME -
+					SNDRV_PCM_HW_PARAM_SAMPLE_BITS + 1];
+	unsigned int rmask;
+	unsigned int cmask;
+	unsigned int info;
+	unsigned int msbits;
+	unsigned int rate_num;
+	unsigned int rate_den;
+	snd_pcm_uframes_t fifo_size;
+	unsigned char reserved[64];
+};
+
+#ifdef CONFIG_SND_SUPPORT_OLD_API
+#define SNDRV_PCM_IOCTL_HW_REFINE_OLD _IOWR('A', 0x10, struct snd_pcm_hw_params_old)
+#define SNDRV_PCM_IOCTL_HW_PARAMS_OLD _IOWR('A', 0x11, struct snd_pcm_hw_params_old)
+
+static int snd_pcm_hw_refine_old_user(struct snd_pcm_substream *substream,
+				      struct snd_pcm_hw_params_old __user * _oparams);
+static int snd_pcm_hw_params_old_user(struct snd_pcm_substream *substream,
+				      struct snd_pcm_hw_params_old __user * _oparams);
+#endif
+static int snd_pcm_open(struct file *file, struct snd_pcm *pcm, int stream);
+
+/*
+ *
+ */
+
+static DEFINE_RWLOCK(snd_pcm_link_rwlock);
+static DECLARE_RWSEM(snd_pcm_link_rwsem);
+
+/* Writer in rwsem may block readers even during its waiting in queue,
+ * and this may lead to a deadlock when the code path takes read sem
+ * twice (e.g. one in snd_pcm_action_nonatomic() and another in
+ * snd_pcm_stream_lock()).  As a (suboptimal) workaround, let writer to
+ * sleep until all the readers are completed without blocking by writer.
+ */
+static inline void down_write_nonfifo(struct rw_semaphore *lock)
+{
+	while (!down_write_trylock(lock))
+		msleep(1);
+}
+
+#define PCM_LOCK_DEFAULT	0
+#define PCM_LOCK_IRQ	1
+#define PCM_LOCK_IRQSAVE	2
+
+static unsigned long __snd_pcm_stream_lock_mode(struct snd_pcm_substream *substream,
+						unsigned int mode)
+{
+	unsigned long flags = 0;
+	if (substream->pcm->nonatomic) {
+		down_read_nested(&snd_pcm_link_rwsem, SINGLE_DEPTH_NESTING);
+		mutex_lock(&substream->self_group.mutex);
+	} else {
+		switch (mode) {
+		case PCM_LOCK_DEFAULT:
+			read_lock(&snd_pcm_link_rwlock);
+			break;
+		case PCM_LOCK_IRQ:
+			read_lock_irq(&snd_pcm_link_rwlock);
+			break;
+		case PCM_LOCK_IRQSAVE:
+			read_lock_irqsave(&snd_pcm_link_rwlock, flags);
+			break;
+		}
+		spin_lock(&substream->self_group.lock);
+	}
+	return flags;
+}
+
+static void __snd_pcm_stream_unlock_mode(struct snd_pcm_substream *substream,
+					 unsigned int mode, unsigned long flags)
+{
+	if (substream->pcm->nonatomic) {
+		mutex_unlock(&substream->self_group.mutex);
+		up_read(&snd_pcm_link_rwsem);
+	} else {
+		spin_unlock(&substream->self_group.lock);
+
+		switch (mode) {
+		case PCM_LOCK_DEFAULT:
+			read_unlock(&snd_pcm_link_rwlock);
+			break;
+		case PCM_LOCK_IRQ:
+			read_unlock_irq(&snd_pcm_link_rwlock);
+			break;
+		case PCM_LOCK_IRQSAVE:
+			read_unlock_irqrestore(&snd_pcm_link_rwlock, flags);
+			break;
+		}
+	}
+}
+
+/**
+ * snd_pcm_stream_lock - Lock the PCM stream
+ * @substream: PCM substream
+ *
+ * This locks the PCM stream's spinlock or mutex depending on the nonatomic
+ * flag of the given substream.  This also takes the global link rw lock
+ * (or rw sem), too, for avoiding the race with linked streams.
+ */
+void snd_pcm_stream_lock(struct snd_pcm_substream *substream)
+{
+	__snd_pcm_stream_lock_mode(substream, PCM_LOCK_DEFAULT);
+}
+EXPORT_SYMBOL_GPL(snd_pcm_stream_lock);
+
+/**
+ * snd_pcm_stream_lock - Unlock the PCM stream
+ * @substream: PCM substream
+ *
+ * This unlocks the PCM stream that has been locked via snd_pcm_stream_lock().
+ */
+void snd_pcm_stream_unlock(struct snd_pcm_substream *substream)
+{
+	__snd_pcm_stream_unlock_mode(substream, PCM_LOCK_DEFAULT, 0);
+}
+EXPORT_SYMBOL_GPL(snd_pcm_stream_unlock);
+
+/**
+ * snd_pcm_stream_lock_irq - Lock the PCM stream
+ * @substream: PCM substream
+ *
+ * This locks the PCM stream like snd_pcm_stream_lock() and disables the local
+ * IRQ (only when nonatomic is false).  In nonatomic case, this is identical
+ * as snd_pcm_stream_lock().
+ */
+void snd_pcm_stream_lock_irq(struct snd_pcm_substream *substream)
+{
+	__snd_pcm_stream_lock_mode(substream, PCM_LOCK_IRQ);
+}
+EXPORT_SYMBOL_GPL(snd_pcm_stream_lock_irq);
+
+/**
+ * snd_pcm_stream_unlock_irq - Unlock the PCM stream
+ * @substream: PCM substream
+ *
+ * This is a counter-part of snd_pcm_stream_lock_irq().
+ */
+void snd_pcm_stream_unlock_irq(struct snd_pcm_substream *substream)
+{
+	__snd_pcm_stream_unlock_mode(substream, PCM_LOCK_IRQ, 0);
+}
+EXPORT_SYMBOL_GPL(snd_pcm_stream_unlock_irq);
+
+unsigned long _snd_pcm_stream_lock_irqsave(struct snd_pcm_substream *substream)
+{
+	return __snd_pcm_stream_lock_mode(substream, PCM_LOCK_IRQSAVE);
+}
+EXPORT_SYMBOL_GPL(_snd_pcm_stream_lock_irqsave);
+
+/**
+ * snd_pcm_stream_unlock_irqrestore - Unlock the PCM stream
+ * @substream: PCM substream
+ * @flags: irq flags
+ *
+ * This is a counter-part of snd_pcm_stream_lock_irqsave().
+ */
+void snd_pcm_stream_unlock_irqrestore(struct snd_pcm_substream *substream,
+				      unsigned long flags)
+{
+	__snd_pcm_stream_unlock_mode(substream, PCM_LOCK_IRQSAVE, flags);
+}
+EXPORT_SYMBOL_GPL(snd_pcm_stream_unlock_irqrestore);
+
+int snd_pcm_info(struct snd_pcm_substream *substream, struct snd_pcm_info *info)
+{
+	struct snd_pcm *pcm = substream->pcm;
+	struct snd_pcm_str *pstr = substream->pstr;
+
+	memset(info, 0, sizeof(*info));
+	info->card = pcm->card->number;
+	info->device = pcm->device;
+	info->stream = substream->stream;
+	info->subdevice = substream->number;
+	strlcpy(info->id, pcm->id, sizeof(info->id));
+	strlcpy(info->name, pcm->name, sizeof(info->name));
+	info->dev_class = pcm->dev_class;
+	info->dev_subclass = pcm->dev_subclass;
+	info->subdevices_count = pstr->substream_count;
+	info->subdevices_avail = pstr->substream_count - pstr->substream_opened;
+	strlcpy(info->subname, substream->name, sizeof(info->subname));
+
+	return 0;
+}
+
+int snd_pcm_info_user(struct snd_pcm_substream *substream,
+		      struct snd_pcm_info __user * _info)
+{
+	struct snd_pcm_info *info;
+	int err;
+
+	info = kmalloc(sizeof(*info), GFP_KERNEL);
+	if (! info)
+		return -ENOMEM;
+	err = snd_pcm_info(substream, info);
+	if (err >= 0) {
+		if (copy_to_user(_info, info, sizeof(*info)))
+			err = -EFAULT;
+	}
+	kfree(info);
+	return err;
+}
+
+static bool hw_support_mmap(struct snd_pcm_substream *substream)
+{
+	if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_MMAP))
+		return false;
+	/* architecture supports dma_mmap_coherent()? */
+#if defined(CONFIG_ARCH_NO_COHERENT_DMA_MMAP) || !defined(CONFIG_HAS_DMA)
+	if (!substream->ops->mmap &&
+	    substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV)
+		return false;
+#endif
+	return true;
+}
+
+static int constrain_mask_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *params)
+{
+	struct snd_pcm_hw_constraints *constrs =
+					&substream->runtime->hw_constraints;
+	struct snd_mask *m;
+	unsigned int k;
+	struct snd_mask old_mask;
+	int changed;
+
+	for (k = SNDRV_PCM_HW_PARAM_FIRST_MASK; k <= SNDRV_PCM_HW_PARAM_LAST_MASK; k++) {
+		m = hw_param_mask(params, k);
+		if (snd_mask_empty(m))
+			return -EINVAL;
+
+		/* This parameter is not requested to change by a caller. */
+		if (!(params->rmask & (1 << k)))
+			continue;
+
+		if (trace_hw_mask_param_enabled())
+			old_mask = *m;
+
+		changed = snd_mask_refine(m, constrs_mask(constrs, k));
+		if (changed < 0)
+			return changed;
+		if (changed == 0)
+			continue;
+
+		/* Set corresponding flag so that the caller gets it. */
+		trace_hw_mask_param(substream, k, 0, &old_mask, m);
+		params->cmask |= 1 << k;
+	}
+
+	return 0;
+}
+
+static int constrain_interval_params(struct snd_pcm_substream *substream,
+				     struct snd_pcm_hw_params *params)
+{
+	struct snd_pcm_hw_constraints *constrs =
+					&substream->runtime->hw_constraints;
+	struct snd_interval *i;
+	unsigned int k;
+	struct snd_interval old_interval;
+	int changed;
+
+	for (k = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++) {
+		i = hw_param_interval(params, k);
+		if (snd_interval_empty(i))
+			return -EINVAL;
+
+		/* This parameter is not requested to change by a caller. */
+		if (!(params->rmask & (1 << k)))
+			continue;
+
+		if (trace_hw_interval_param_enabled())
+			old_interval = *i;
+
+		changed = snd_interval_refine(i, constrs_interval(constrs, k));
+		if (changed < 0)
+			return changed;
+		if (changed == 0)
+			continue;
+
+		/* Set corresponding flag so that the caller gets it. */
+		trace_hw_interval_param(substream, k, 0, &old_interval, i);
+		params->cmask |= 1 << k;
+	}
+
+	return 0;
+}
+
+static int constrain_params_by_rules(struct snd_pcm_substream *substream,
+				     struct snd_pcm_hw_params *params)
+{
+	struct snd_pcm_hw_constraints *constrs =
+					&substream->runtime->hw_constraints;
+	unsigned int k;
+	unsigned int *rstamps;
+	unsigned int vstamps[SNDRV_PCM_HW_PARAM_LAST_INTERVAL + 1];
+	unsigned int stamp;
+	struct snd_pcm_hw_rule *r;
+	unsigned int d;
+	struct snd_mask old_mask;
+	struct snd_interval old_interval;
+	bool again;
+	int changed, err = 0;
+
+	/*
+	 * Each application of rule has own sequence number.
+	 *
+	 * Each member of 'rstamps' array represents the sequence number of
+	 * recent application of corresponding rule.
+	 */
+	rstamps = kcalloc(constrs->rules_num, sizeof(unsigned int), GFP_KERNEL);
+	if (!rstamps)
+		return -ENOMEM;
+
+	/*
+	 * Each member of 'vstamps' array represents the sequence number of
+	 * recent application of rule in which corresponding parameters were
+	 * changed.
+	 *
+	 * In initial state, elements corresponding to parameters requested by
+	 * a caller is 1. For unrequested parameters, corresponding members
+	 * have 0 so that the parameters are never changed anymore.
+	 */
+	for (k = 0; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++)
+		vstamps[k] = (params->rmask & (1 << k)) ? 1 : 0;
+
+	/* Due to the above design, actual sequence number starts at 2. */
+	stamp = 2;
+retry:
+	/* Apply all rules in order. */
+	again = false;
+	for (k = 0; k < constrs->rules_num; k++) {
+		r = &constrs->rules[k];
+
+		/*
+		 * Check condition bits of this rule. When the rule has
+		 * some condition bits, parameter without the bits is
+		 * never processed. SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP
+		 * is an example of the condition bits.
+		 */
+		if (r->cond && !(r->cond & params->flags))
+			continue;
+
+		/*
+		 * The 'deps' array includes maximum three dependencies
+		 * to SNDRV_PCM_HW_PARAM_XXXs for this rule. The fourth
+		 * member of this array is a sentinel and should be
+		 * negative value.
+		 *
+		 * This rule should be processed in this time when dependent
+		 * parameters were changed at former applications of the other
+		 * rules.
+		 */
+		for (d = 0; r->deps[d] >= 0; d++) {
+			if (vstamps[r->deps[d]] > rstamps[k])
+				break;
+		}
+		if (r->deps[d] < 0)
+			continue;
+
+		if (trace_hw_mask_param_enabled()) {
+			if (hw_is_mask(r->var))
+				old_mask = *hw_param_mask(params, r->var);
+		}
+		if (trace_hw_interval_param_enabled()) {
+			if (hw_is_interval(r->var))
+				old_interval = *hw_param_interval(params, r->var);
+		}
+
+		changed = r->func(params, r);
+		if (changed < 0) {
+			err = changed;
+			goto out;
+		}
+
+		/*
+		 * When the parameter is changed, notify it to the caller
+		 * by corresponding returned bit, then preparing for next
+		 * iteration.
+		 */
+		if (changed && r->var >= 0) {
+			if (hw_is_mask(r->var)) {
+				trace_hw_mask_param(substream, r->var,
+					k + 1, &old_mask,
+					hw_param_mask(params, r->var));
+			}
+			if (hw_is_interval(r->var)) {
+				trace_hw_interval_param(substream, r->var,
+					k + 1, &old_interval,
+					hw_param_interval(params, r->var));
+			}
+
+			params->cmask |= (1 << r->var);
+			vstamps[r->var] = stamp;
+			again = true;
+		}
+
+		rstamps[k] = stamp++;
+	}
+
+	/* Iterate to evaluate all rules till no parameters are changed. */
+	if (again)
+		goto retry;
+
+ out:
+	kfree(rstamps);
+	return err;
+}
+
+static int fixup_unreferenced_params(struct snd_pcm_substream *substream,
+				     struct snd_pcm_hw_params *params)
+{
+	const struct snd_interval *i;
+	const struct snd_mask *m;
+	int err;
+
+	if (!params->msbits) {
+		i = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS);
+		if (snd_interval_single(i))
+			params->msbits = snd_interval_value(i);
+	}
+
+	if (!params->rate_den) {
+		i = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_RATE);
+		if (snd_interval_single(i)) {
+			params->rate_num = snd_interval_value(i);
+			params->rate_den = 1;
+		}
+	}
+
+	if (!params->fifo_size) {
+		m = hw_param_mask_c(params, SNDRV_PCM_HW_PARAM_FORMAT);
+		i = hw_param_interval_c(params, SNDRV_PCM_HW_PARAM_CHANNELS);
+		if (snd_mask_single(m) && snd_interval_single(i)) {
+			err = substream->ops->ioctl(substream,
+					SNDRV_PCM_IOCTL1_FIFO_SIZE, params);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	if (!params->info) {
+		params->info = substream->runtime->hw.info;
+		params->info &= ~(SNDRV_PCM_INFO_FIFO_IN_FRAMES |
+				  SNDRV_PCM_INFO_DRAIN_TRIGGER);
+		if (!hw_support_mmap(substream))
+			params->info &= ~(SNDRV_PCM_INFO_MMAP |
+					  SNDRV_PCM_INFO_MMAP_VALID);
+	}
+
+	return 0;
+}
+
+int snd_pcm_hw_refine(struct snd_pcm_substream *substream,
+		      struct snd_pcm_hw_params *params)
+{
+	int err;
+
+	params->info = 0;
+	params->fifo_size = 0;
+	if (params->rmask & (1 << SNDRV_PCM_HW_PARAM_SAMPLE_BITS))
+		params->msbits = 0;
+	if (params->rmask & (1 << SNDRV_PCM_HW_PARAM_RATE)) {
+		params->rate_num = 0;
+		params->rate_den = 0;
+	}
+
+	err = constrain_mask_params(substream, params);
+	if (err < 0)
+		return err;
+
+	err = constrain_interval_params(substream, params);
+	if (err < 0)
+		return err;
+
+	err = constrain_params_by_rules(substream, params);
+	if (err < 0)
+		return err;
+
+	params->rmask = 0;
+
+	return 0;
+}
+EXPORT_SYMBOL(snd_pcm_hw_refine);
+
+static int snd_pcm_hw_refine_user(struct snd_pcm_substream *substream,
+				  struct snd_pcm_hw_params __user * _params)
+{
+	struct snd_pcm_hw_params *params;
+	int err;
+
+	params = memdup_user(_params, sizeof(*params));
+	if (IS_ERR(params))
+		return PTR_ERR(params);
+
+	err = snd_pcm_hw_refine(substream, params);
+	if (err < 0)
+		goto end;
+
+	err = fixup_unreferenced_params(substream, params);
+	if (err < 0)
+		goto end;
+
+	if (copy_to_user(_params, params, sizeof(*params)))
+		err = -EFAULT;
+end:
+	kfree(params);
+	return err;
+}
+
+static int period_to_usecs(struct snd_pcm_runtime *runtime)
+{
+	int usecs;
+
+	if (! runtime->rate)
+		return -1; /* invalid */
+
+	/* take 75% of period time as the deadline */
+	usecs = (750000 / runtime->rate) * runtime->period_size;
+	usecs += ((750000 % runtime->rate) * runtime->period_size) /
+		runtime->rate;
+
+	return usecs;
+}
+
+static void snd_pcm_set_state(struct snd_pcm_substream *substream, int state)
+{
+	snd_pcm_stream_lock_irq(substream);
+	if (substream->runtime->status->state != SNDRV_PCM_STATE_DISCONNECTED)
+		substream->runtime->status->state = state;
+	snd_pcm_stream_unlock_irq(substream);
+}
+
+static inline void snd_pcm_timer_notify(struct snd_pcm_substream *substream,
+					int event)
+{
+#ifdef CONFIG_SND_PCM_TIMER
+	if (substream->timer)
+		snd_timer_notify(substream->timer, event,
+					&substream->runtime->trigger_tstamp);
+#endif
+}
+
+/**
+ * snd_pcm_hw_param_choose - choose a configuration defined by @params
+ * @pcm: PCM instance
+ * @params: the hw_params instance
+ *
+ * Choose one configuration from configuration space defined by @params.
+ * The configuration chosen is that obtained fixing in this order:
+ * first access, first format, first subformat, min channels,
+ * min rate, min period time, max buffer size, min tick time
+ *
+ * Return: Zero if successful, or a negative error code on failure.
+ */
+static int snd_pcm_hw_params_choose(struct snd_pcm_substream *pcm,
+				    struct snd_pcm_hw_params *params)
+{
+	static const int vars[] = {
+		SNDRV_PCM_HW_PARAM_ACCESS,
+		SNDRV_PCM_HW_PARAM_FORMAT,
+		SNDRV_PCM_HW_PARAM_SUBFORMAT,
+		SNDRV_PCM_HW_PARAM_CHANNELS,
+		SNDRV_PCM_HW_PARAM_RATE,
+		SNDRV_PCM_HW_PARAM_PERIOD_TIME,
+		SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
+		SNDRV_PCM_HW_PARAM_TICK_TIME,
+		-1
+	};
+	const int *v;
+	struct snd_mask old_mask;
+	struct snd_interval old_interval;
+	int changed;
+
+	for (v = vars; *v != -1; v++) {
+		/* Keep old parameter to trace. */
+		if (trace_hw_mask_param_enabled()) {
+			if (hw_is_mask(*v))
+				old_mask = *hw_param_mask(params, *v);
+		}
+		if (trace_hw_interval_param_enabled()) {
+			if (hw_is_interval(*v))
+				old_interval = *hw_param_interval(params, *v);
+		}
+		if (*v != SNDRV_PCM_HW_PARAM_BUFFER_SIZE)
+			changed = snd_pcm_hw_param_first(pcm, params, *v, NULL);
+		else
+			changed = snd_pcm_hw_param_last(pcm, params, *v, NULL);
+		if (changed < 0)
+			return changed;
+		if (changed == 0)
+			continue;
+
+		/* Trace the changed parameter. */
+		if (hw_is_mask(*v)) {
+			trace_hw_mask_param(pcm, *v, 0, &old_mask,
+					    hw_param_mask(params, *v));
+		}
+		if (hw_is_interval(*v)) {
+			trace_hw_interval_param(pcm, *v, 0, &old_interval,
+						hw_param_interval(params, *v));
+		}
+	}
+
+	return 0;
+}
+
+/* acquire buffer_mutex; if it's in r/w operation, return -EBUSY, otherwise
+ * block the further r/w operations
+ */
+static int snd_pcm_buffer_access_lock(struct snd_pcm_runtime *runtime)
+{
+	if (!atomic_dec_unless_positive(&runtime->buffer_accessing))
+		return -EBUSY;
+	mutex_lock(&runtime->buffer_mutex);
+	return 0; /* keep buffer_mutex, unlocked by below */
+}
+
+/* release buffer_mutex and clear r/w access flag */
+static void snd_pcm_buffer_access_unlock(struct snd_pcm_runtime *runtime)
+{
+	mutex_unlock(&runtime->buffer_mutex);
+	atomic_inc(&runtime->buffer_accessing);
+}
+
+#if IS_ENABLED(CONFIG_SND_PCM_OSS)
+#define is_oss_stream(substream)	((substream)->oss.oss)
+#else
+#define is_oss_stream(substream)	false
+#endif
+
+static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
+			     struct snd_pcm_hw_params *params)
+{
+	struct snd_pcm_runtime *runtime;
+	int err, usecs;
+	unsigned int bits;
+	snd_pcm_uframes_t frames;
+
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+	runtime = substream->runtime;
+	err = snd_pcm_buffer_access_lock(runtime);
+	if (err < 0)
+		return err;
+	snd_pcm_stream_lock_irq(substream);
+	switch (runtime->status->state) {
+	case SNDRV_PCM_STATE_OPEN:
+	case SNDRV_PCM_STATE_SETUP:
+	case SNDRV_PCM_STATE_PREPARED:
+		if (!is_oss_stream(substream) &&
+		    atomic_read(&substream->mmap_count))
+			err = -EBADFD;
+		break;
+	default:
+		err = -EBADFD;
+		break;
+	}
+	snd_pcm_stream_unlock_irq(substream);
+	if (err)
+		goto unlock;
+
+	params->rmask = ~0U;
+	err = snd_pcm_hw_refine(substream, params);
+	if (err < 0)
+		goto _error;
+
+	err = snd_pcm_hw_params_choose(substream, params);
+	if (err < 0)
+		goto _error;
+
+	err = fixup_unreferenced_params(substream, params);
+	if (err < 0)
+		goto _error;
+
+	if (substream->ops->hw_params != NULL) {
+		err = substream->ops->hw_params(substream, params);
+		if (err < 0)
+			goto _error;
+	}
+
+	runtime->access = params_access(params);
+	runtime->format = params_format(params);
+	runtime->subformat = params_subformat(params);
+	runtime->channels = params_channels(params);
+	runtime->rate = params_rate(params);
+	runtime->period_size = params_period_size(params);
+	runtime->periods = params_periods(params);
+	runtime->buffer_size = params_buffer_size(params);
+	runtime->info = params->info;
+	runtime->rate_num = params->rate_num;
+	runtime->rate_den = params->rate_den;
+	runtime->no_period_wakeup =
+			(params->info & SNDRV_PCM_INFO_NO_PERIOD_WAKEUP) &&
+			(params->flags & SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP);
+
+	bits = snd_pcm_format_physical_width(runtime->format);
+	runtime->sample_bits = bits;
+	bits *= runtime->channels;
+	runtime->frame_bits = bits;
+	frames = 1;
+	while (bits % 8 != 0) {
+		bits *= 2;
+		frames *= 2;
+	}
+	runtime->byte_align = bits / 8;
+	runtime->min_align = frames;
+
+	/* Default sw params */
+	runtime->tstamp_mode = SNDRV_PCM_TSTAMP_NONE;
+	runtime->period_step = 1;
+	runtime->control->avail_min = runtime->period_size;
+	runtime->start_threshold = 1;
+	runtime->stop_threshold = runtime->buffer_size;
+	runtime->silence_threshold = 0;
+	runtime->silence_size = 0;
+	runtime->boundary = runtime->buffer_size;
+	while (runtime->boundary * 2 <= LONG_MAX - runtime->buffer_size)
+		runtime->boundary *= 2;
+
+	/* clear the buffer for avoiding possible kernel info leaks */
+	if (runtime->dma_area && !substream->ops->copy_user) {
+		size_t size = runtime->dma_bytes;
+
+		if (runtime->info & SNDRV_PCM_INFO_MMAP)
+			size = PAGE_ALIGN(size);
+		memset(runtime->dma_area, 0, size);
+	}
+
+	snd_pcm_timer_resolution_change(substream);
+	snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP);
+
+	if (pm_qos_request_active(&substream->latency_pm_qos_req))
+		pm_qos_remove_request(&substream->latency_pm_qos_req);
+	if ((usecs = period_to_usecs(runtime)) >= 0)
+		pm_qos_add_request(&substream->latency_pm_qos_req,
+				   PM_QOS_CPU_DMA_LATENCY, usecs);
+	err = 0;
+ _error:
+	if (err) {
+		/* hardware might be unusable from this time,
+		 * so we force application to retry to set
+		 * the correct hardware parameter settings
+		 */
+		snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);
+		if (substream->ops->hw_free != NULL)
+			substream->ops->hw_free(substream);
+	}
+ unlock:
+	snd_pcm_buffer_access_unlock(runtime);
+	return err;
+}
+
+static int snd_pcm_hw_params_user(struct snd_pcm_substream *substream,
+				  struct snd_pcm_hw_params __user * _params)
+{
+	struct snd_pcm_hw_params *params;
+	int err;
+
+	params = memdup_user(_params, sizeof(*params));
+	if (IS_ERR(params))
+		return PTR_ERR(params);
+
+	err = snd_pcm_hw_params(substream, params);
+	if (err < 0)
+		goto end;
+
+	if (copy_to_user(_params, params, sizeof(*params)))
+		err = -EFAULT;
+end:
+	kfree(params);
+	return err;
+}
+
+static int snd_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime;
+	int result = 0;
+
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+	runtime = substream->runtime;
+	result = snd_pcm_buffer_access_lock(runtime);
+	if (result < 0)
+		return result;
+	snd_pcm_stream_lock_irq(substream);
+	switch (runtime->status->state) {
+	case SNDRV_PCM_STATE_SETUP:
+	case SNDRV_PCM_STATE_PREPARED:
+		if (atomic_read(&substream->mmap_count))
+			result = -EBADFD;
+		break;
+	default:
+		result = -EBADFD;
+		break;
+	}
+	snd_pcm_stream_unlock_irq(substream);
+	if (result)
+		goto unlock;
+	if (substream->ops->hw_free)
+		result = substream->ops->hw_free(substream);
+	snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);
+	pm_qos_remove_request(&substream->latency_pm_qos_req);
+ unlock:
+	snd_pcm_buffer_access_unlock(runtime);
+	return result;
+}
+
+static int snd_pcm_sw_params(struct snd_pcm_substream *substream,
+			     struct snd_pcm_sw_params *params)
+{
+	struct snd_pcm_runtime *runtime;
+	int err;
+
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+	runtime = substream->runtime;
+	snd_pcm_stream_lock_irq(substream);
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
+		snd_pcm_stream_unlock_irq(substream);
+		return -EBADFD;
+	}
+	snd_pcm_stream_unlock_irq(substream);
+
+	if (params->tstamp_mode < 0 ||
+	    params->tstamp_mode > SNDRV_PCM_TSTAMP_LAST)
+		return -EINVAL;
+	if (params->proto >= SNDRV_PROTOCOL_VERSION(2, 0, 12) &&
+	    params->tstamp_type > SNDRV_PCM_TSTAMP_TYPE_LAST)
+		return -EINVAL;
+	if (params->avail_min == 0)
+		return -EINVAL;
+	if (params->silence_size >= runtime->boundary) {
+		if (params->silence_threshold != 0)
+			return -EINVAL;
+	} else {
+		if (params->silence_size > params->silence_threshold)
+			return -EINVAL;
+		if (params->silence_threshold > runtime->buffer_size)
+			return -EINVAL;
+	}
+	err = 0;
+	snd_pcm_stream_lock_irq(substream);
+	runtime->tstamp_mode = params->tstamp_mode;
+	if (params->proto >= SNDRV_PROTOCOL_VERSION(2, 0, 12))
+		runtime->tstamp_type = params->tstamp_type;
+	runtime->period_step = params->period_step;
+	runtime->control->avail_min = params->avail_min;
+	runtime->start_threshold = params->start_threshold;
+	runtime->stop_threshold = params->stop_threshold;
+	runtime->silence_threshold = params->silence_threshold;
+	runtime->silence_size = params->silence_size;
+        params->boundary = runtime->boundary;
+	if (snd_pcm_running(substream)) {
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
+		    runtime->silence_size > 0)
+			snd_pcm_playback_silence(substream, ULONG_MAX);
+		err = snd_pcm_update_state(substream, runtime);
+	}
+	snd_pcm_stream_unlock_irq(substream);
+	return err;
+}
+
+static int snd_pcm_sw_params_user(struct snd_pcm_substream *substream,
+				  struct snd_pcm_sw_params __user * _params)
+{
+	struct snd_pcm_sw_params params;
+	int err;
+	if (copy_from_user(&params, _params, sizeof(params)))
+		return -EFAULT;
+	err = snd_pcm_sw_params(substream, &params);
+	if (copy_to_user(_params, &params, sizeof(params)))
+		return -EFAULT;
+	return err;
+}
+
+static inline snd_pcm_uframes_t
+snd_pcm_calc_delay(struct snd_pcm_substream *substream)
+{
+	snd_pcm_uframes_t delay;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		delay = snd_pcm_playback_hw_avail(substream->runtime);
+	else
+		delay = snd_pcm_capture_avail(substream->runtime);
+	return delay + substream->runtime->delay;
+}
+
+int snd_pcm_status(struct snd_pcm_substream *substream,
+		   struct snd_pcm_status *status)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	snd_pcm_stream_lock_irq(substream);
+
+	snd_pcm_unpack_audio_tstamp_config(status->audio_tstamp_data,
+					&runtime->audio_tstamp_config);
+
+	/* backwards compatible behavior */
+	if (runtime->audio_tstamp_config.type_requested ==
+		SNDRV_PCM_AUDIO_TSTAMP_TYPE_COMPAT) {
+		if (runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK)
+			runtime->audio_tstamp_config.type_requested =
+				SNDRV_PCM_AUDIO_TSTAMP_TYPE_LINK;
+		else
+			runtime->audio_tstamp_config.type_requested =
+				SNDRV_PCM_AUDIO_TSTAMP_TYPE_DEFAULT;
+		runtime->audio_tstamp_report.valid = 0;
+	} else
+		runtime->audio_tstamp_report.valid = 1;
+
+	status->state = runtime->status->state;
+	status->suspended_state = runtime->status->suspended_state;
+	if (status->state == SNDRV_PCM_STATE_OPEN)
+		goto _end;
+	status->trigger_tstamp = runtime->trigger_tstamp;
+	if (snd_pcm_running(substream)) {
+		snd_pcm_update_hw_ptr(substream);
+		if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) {
+			status->tstamp = runtime->status->tstamp;
+			status->driver_tstamp = runtime->driver_tstamp;
+			status->audio_tstamp =
+				runtime->status->audio_tstamp;
+			if (runtime->audio_tstamp_report.valid == 1)
+				/* backwards compatibility, no report provided in COMPAT mode */
+				snd_pcm_pack_audio_tstamp_report(&status->audio_tstamp_data,
+								&status->audio_tstamp_accuracy,
+								&runtime->audio_tstamp_report);
+
+			goto _tstamp_end;
+		}
+	} else {
+		/* get tstamp only in fallback mode and only if enabled */
+		if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE)
+			snd_pcm_gettime(runtime, &status->tstamp);
+	}
+ _tstamp_end:
+	status->appl_ptr = runtime->control->appl_ptr;
+	status->hw_ptr = runtime->status->hw_ptr;
+	status->avail = snd_pcm_avail(substream);
+	status->delay = snd_pcm_running(substream) ?
+		snd_pcm_calc_delay(substream) : 0;
+	status->avail_max = runtime->avail_max;
+	status->overrange = runtime->overrange;
+	runtime->avail_max = 0;
+	runtime->overrange = 0;
+ _end:
+ 	snd_pcm_stream_unlock_irq(substream);
+	return 0;
+}
+
+static int snd_pcm_status_user(struct snd_pcm_substream *substream,
+			       struct snd_pcm_status __user * _status,
+			       bool ext)
+{
+	struct snd_pcm_status status;
+	int res;
+
+	memset(&status, 0, sizeof(status));
+	/*
+	 * with extension, parameters are read/write,
+	 * get audio_tstamp_data from user,
+	 * ignore rest of status structure
+	 */
+	if (ext && get_user(status.audio_tstamp_data,
+				(u32 __user *)(&_status->audio_tstamp_data)))
+		return -EFAULT;
+	res = snd_pcm_status(substream, &status);
+	if (res < 0)
+		return res;
+	if (copy_to_user(_status, &status, sizeof(status)))
+		return -EFAULT;
+	return 0;
+}
+
+static int snd_pcm_channel_info(struct snd_pcm_substream *substream,
+				struct snd_pcm_channel_info * info)
+{
+	struct snd_pcm_runtime *runtime;
+	unsigned int channel;
+	
+	channel = info->channel;
+	runtime = substream->runtime;
+	snd_pcm_stream_lock_irq(substream);
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN) {
+		snd_pcm_stream_unlock_irq(substream);
+		return -EBADFD;
+	}
+	snd_pcm_stream_unlock_irq(substream);
+	if (channel >= runtime->channels)
+		return -EINVAL;
+	memset(info, 0, sizeof(*info));
+	info->channel = channel;
+	return substream->ops->ioctl(substream, SNDRV_PCM_IOCTL1_CHANNEL_INFO, info);
+}
+
+static int snd_pcm_channel_info_user(struct snd_pcm_substream *substream,
+				     struct snd_pcm_channel_info __user * _info)
+{
+	struct snd_pcm_channel_info info;
+	int res;
+	
+	if (copy_from_user(&info, _info, sizeof(info)))
+		return -EFAULT;
+	res = snd_pcm_channel_info(substream, &info);
+	if (res < 0)
+		return res;
+	if (copy_to_user(_info, &info, sizeof(info)))
+		return -EFAULT;
+	return 0;
+}
+
+static void snd_pcm_trigger_tstamp(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (runtime->trigger_master == NULL)
+		return;
+	if (runtime->trigger_master == substream) {
+		if (!runtime->trigger_tstamp_latched)
+			snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
+	} else {
+		snd_pcm_trigger_tstamp(runtime->trigger_master);
+		runtime->trigger_tstamp = runtime->trigger_master->runtime->trigger_tstamp;
+	}
+	runtime->trigger_master = NULL;
+}
+
+struct action_ops {
+	int (*pre_action)(struct snd_pcm_substream *substream, int state);
+	int (*do_action)(struct snd_pcm_substream *substream, int state);
+	void (*undo_action)(struct snd_pcm_substream *substream, int state);
+	void (*post_action)(struct snd_pcm_substream *substream, int state);
+};
+
+/*
+ *  this functions is core for handling of linked stream
+ *  Note: the stream state might be changed also on failure
+ *  Note2: call with calling stream lock + link lock
+ */
+static int snd_pcm_action_group(const struct action_ops *ops,
+				struct snd_pcm_substream *substream,
+				int state, int stream_lock)
+{
+	struct snd_pcm_substream *s = NULL;
+	struct snd_pcm_substream *s1;
+	int res = 0, depth = 1;
+
+	snd_pcm_group_for_each_entry(s, substream) {
+		if (s != substream) {
+			if (!stream_lock)
+				mutex_lock_nested(&s->runtime->buffer_mutex, depth);
+			else if (s->pcm->nonatomic)
+				mutex_lock_nested(&s->self_group.mutex, depth);
+			else
+				spin_lock_nested(&s->self_group.lock, depth);
+			depth++;
+		}
+		res = ops->pre_action(s, state);
+		if (res < 0)
+			goto _unlock;
+	}
+	snd_pcm_group_for_each_entry(s, substream) {
+		res = ops->do_action(s, state);
+		if (res < 0) {
+			if (ops->undo_action) {
+				snd_pcm_group_for_each_entry(s1, substream) {
+					if (s1 == s) /* failed stream */
+						break;
+					ops->undo_action(s1, state);
+				}
+			}
+			s = NULL; /* unlock all */
+			goto _unlock;
+		}
+	}
+	snd_pcm_group_for_each_entry(s, substream) {
+		ops->post_action(s, state);
+	}
+ _unlock:
+	/* unlock streams */
+	snd_pcm_group_for_each_entry(s1, substream) {
+		if (s1 != substream) {
+			if (!stream_lock)
+				mutex_unlock(&s1->runtime->buffer_mutex);
+			else if (s1->pcm->nonatomic)
+				mutex_unlock(&s1->self_group.mutex);
+			else
+				spin_unlock(&s1->self_group.lock);
+		}
+		if (s1 == s)	/* end */
+			break;
+	}
+	return res;
+}
+
+/*
+ *  Note: call with stream lock
+ */
+static int snd_pcm_action_single(const struct action_ops *ops,
+				 struct snd_pcm_substream *substream,
+				 int state)
+{
+	int res;
+	
+	res = ops->pre_action(substream, state);
+	if (res < 0)
+		return res;
+	res = ops->do_action(substream, state);
+	if (res == 0)
+		ops->post_action(substream, state);
+	else if (ops->undo_action)
+		ops->undo_action(substream, state);
+	return res;
+}
+
+/*
+ *  Note: call with stream lock
+ */
+static int snd_pcm_action(const struct action_ops *ops,
+			  struct snd_pcm_substream *substream,
+			  int state)
+{
+	int res;
+
+	if (!snd_pcm_stream_linked(substream))
+		return snd_pcm_action_single(ops, substream, state);
+
+	if (substream->pcm->nonatomic) {
+		if (!mutex_trylock(&substream->group->mutex)) {
+			mutex_unlock(&substream->self_group.mutex);
+			mutex_lock(&substream->group->mutex);
+			mutex_lock(&substream->self_group.mutex);
+		}
+		res = snd_pcm_action_group(ops, substream, state, 1);
+		mutex_unlock(&substream->group->mutex);
+	} else {
+		if (!spin_trylock(&substream->group->lock)) {
+			spin_unlock(&substream->self_group.lock);
+			spin_lock(&substream->group->lock);
+			spin_lock(&substream->self_group.lock);
+		}
+		res = snd_pcm_action_group(ops, substream, state, 1);
+		spin_unlock(&substream->group->lock);
+	}
+	return res;
+}
+
+/*
+ *  Note: don't use any locks before
+ */
+static int snd_pcm_action_lock_irq(const struct action_ops *ops,
+				   struct snd_pcm_substream *substream,
+				   int state)
+{
+	int res;
+
+	snd_pcm_stream_lock_irq(substream);
+	res = snd_pcm_action(ops, substream, state);
+	snd_pcm_stream_unlock_irq(substream);
+	return res;
+}
+
+/*
+ */
+static int snd_pcm_action_nonatomic(const struct action_ops *ops,
+				    struct snd_pcm_substream *substream,
+				    int state)
+{
+	int res;
+
+	down_read(&snd_pcm_link_rwsem);
+	res = snd_pcm_buffer_access_lock(substream->runtime);
+	if (res < 0)
+		goto unlock;
+	if (snd_pcm_stream_linked(substream))
+		res = snd_pcm_action_group(ops, substream, state, 0);
+	else
+		res = snd_pcm_action_single(ops, substream, state);
+	snd_pcm_buffer_access_unlock(substream->runtime);
+ unlock:
+	up_read(&snd_pcm_link_rwsem);
+	return res;
+}
+
+/*
+ * start callbacks
+ */
+static int snd_pcm_pre_start(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (runtime->status->state != SNDRV_PCM_STATE_PREPARED)
+		return -EBADFD;
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
+	    !snd_pcm_playback_data(substream))
+		return -EPIPE;
+	runtime->trigger_tstamp_latched = false;
+	runtime->trigger_master = substream;
+	return 0;
+}
+
+static int snd_pcm_do_start(struct snd_pcm_substream *substream, int state)
+{
+	if (substream->runtime->trigger_master != substream)
+		return 0;
+	return substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_START);
+}
+
+static void snd_pcm_undo_start(struct snd_pcm_substream *substream, int state)
+{
+	if (substream->runtime->trigger_master == substream)
+		substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_STOP);
+}
+
+static void snd_pcm_post_start(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_trigger_tstamp(substream);
+	runtime->hw_ptr_jiffies = jiffies;
+	runtime->hw_ptr_buffer_jiffies = (runtime->buffer_size * HZ) / 
+							    runtime->rate;
+	runtime->status->state = state;
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
+	    runtime->silence_size > 0)
+		snd_pcm_playback_silence(substream, ULONG_MAX);
+	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSTART);
+}
+
+static const struct action_ops snd_pcm_action_start = {
+	.pre_action = snd_pcm_pre_start,
+	.do_action = snd_pcm_do_start,
+	.undo_action = snd_pcm_undo_start,
+	.post_action = snd_pcm_post_start
+};
+
+/**
+ * snd_pcm_start - start all linked streams
+ * @substream: the PCM substream instance
+ *
+ * Return: Zero if successful, or a negative error code.
+ * The stream lock must be acquired before calling this function.
+ */
+int snd_pcm_start(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_action(&snd_pcm_action_start, substream,
+			      SNDRV_PCM_STATE_RUNNING);
+}
+
+/* take the stream lock and start the streams */
+static int snd_pcm_start_lock_irq(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_action_lock_irq(&snd_pcm_action_start, substream,
+				       SNDRV_PCM_STATE_RUNNING);
+}
+
+/*
+ * stop callbacks
+ */
+static int snd_pcm_pre_stop(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+		return -EBADFD;
+	runtime->trigger_master = substream;
+	return 0;
+}
+
+static int snd_pcm_do_stop(struct snd_pcm_substream *substream, int state)
+{
+	if (substream->runtime->trigger_master == substream &&
+	    snd_pcm_running(substream))
+		substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_STOP);
+	return 0; /* unconditonally stop all substreams */
+}
+
+static void snd_pcm_post_stop(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (runtime->status->state != state) {
+		snd_pcm_trigger_tstamp(substream);
+		runtime->status->state = state;
+		snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSTOP);
+	}
+	wake_up(&runtime->sleep);
+	wake_up(&runtime->tsleep);
+}
+
+static const struct action_ops snd_pcm_action_stop = {
+	.pre_action = snd_pcm_pre_stop,
+	.do_action = snd_pcm_do_stop,
+	.post_action = snd_pcm_post_stop
+};
+
+/**
+ * snd_pcm_stop - try to stop all running streams in the substream group
+ * @substream: the PCM substream instance
+ * @state: PCM state after stopping the stream
+ *
+ * The state of each stream is then changed to the given state unconditionally.
+ *
+ * Return: Zero if successful, or a negative error code.
+ */
+int snd_pcm_stop(struct snd_pcm_substream *substream, snd_pcm_state_t state)
+{
+	return snd_pcm_action(&snd_pcm_action_stop, substream, state);
+}
+EXPORT_SYMBOL(snd_pcm_stop);
+
+/**
+ * snd_pcm_drain_done - stop the DMA only when the given stream is playback
+ * @substream: the PCM substream
+ *
+ * After stopping, the state is changed to SETUP.
+ * Unlike snd_pcm_stop(), this affects only the given stream.
+ *
+ * Return: Zero if succesful, or a negative error code.
+ */
+int snd_pcm_drain_done(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_action_single(&snd_pcm_action_stop, substream,
+				     SNDRV_PCM_STATE_SETUP);
+}
+
+/**
+ * snd_pcm_stop_xrun - stop the running streams as XRUN
+ * @substream: the PCM substream instance
+ *
+ * This stops the given running substream (and all linked substreams) as XRUN.
+ * Unlike snd_pcm_stop(), this function takes the substream lock by itself.
+ *
+ * Return: Zero if successful, or a negative error code.
+ */
+int snd_pcm_stop_xrun(struct snd_pcm_substream *substream)
+{
+	unsigned long flags;
+
+	snd_pcm_stream_lock_irqsave(substream, flags);
+	if (substream->runtime && snd_pcm_running(substream))
+		__snd_pcm_xrun(substream);
+	snd_pcm_stream_unlock_irqrestore(substream, flags);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_pcm_stop_xrun);
+
+/*
+ * pause callbacks
+ */
+static int snd_pcm_pre_pause(struct snd_pcm_substream *substream, int push)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (!(runtime->info & SNDRV_PCM_INFO_PAUSE))
+		return -ENOSYS;
+	if (push) {
+		if (runtime->status->state != SNDRV_PCM_STATE_RUNNING)
+			return -EBADFD;
+	} else if (runtime->status->state != SNDRV_PCM_STATE_PAUSED)
+		return -EBADFD;
+	runtime->trigger_master = substream;
+	return 0;
+}
+
+static int snd_pcm_do_pause(struct snd_pcm_substream *substream, int push)
+{
+	if (substream->runtime->trigger_master != substream)
+		return 0;
+	/* some drivers might use hw_ptr to recover from the pause -
+	   update the hw_ptr now */
+	if (push)
+		snd_pcm_update_hw_ptr(substream);
+	/* The jiffies check in snd_pcm_update_hw_ptr*() is done by
+	 * a delta between the current jiffies, this gives a large enough
+	 * delta, effectively to skip the check once.
+	 */
+	substream->runtime->hw_ptr_jiffies = jiffies - HZ * 1000;
+	return substream->ops->trigger(substream,
+				       push ? SNDRV_PCM_TRIGGER_PAUSE_PUSH :
+					      SNDRV_PCM_TRIGGER_PAUSE_RELEASE);
+}
+
+static void snd_pcm_undo_pause(struct snd_pcm_substream *substream, int push)
+{
+	if (substream->runtime->trigger_master == substream)
+		substream->ops->trigger(substream,
+					push ? SNDRV_PCM_TRIGGER_PAUSE_RELEASE :
+					SNDRV_PCM_TRIGGER_PAUSE_PUSH);
+}
+
+static void snd_pcm_post_pause(struct snd_pcm_substream *substream, int push)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_trigger_tstamp(substream);
+	if (push) {
+		runtime->status->state = SNDRV_PCM_STATE_PAUSED;
+		snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MPAUSE);
+		wake_up(&runtime->sleep);
+		wake_up(&runtime->tsleep);
+	} else {
+		runtime->status->state = SNDRV_PCM_STATE_RUNNING;
+		snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MCONTINUE);
+	}
+}
+
+static const struct action_ops snd_pcm_action_pause = {
+	.pre_action = snd_pcm_pre_pause,
+	.do_action = snd_pcm_do_pause,
+	.undo_action = snd_pcm_undo_pause,
+	.post_action = snd_pcm_post_pause
+};
+
+/*
+ * Push/release the pause for all linked streams.
+ */
+static int snd_pcm_pause(struct snd_pcm_substream *substream, int push)
+{
+	return snd_pcm_action(&snd_pcm_action_pause, substream, push);
+}
+
+#ifdef CONFIG_PM
+/* suspend */
+
+static int snd_pcm_pre_suspend(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	switch (runtime->status->state) {
+	case SNDRV_PCM_STATE_SUSPENDED:
+		return -EBUSY;
+	/* unresumable PCM state; return -EBUSY for skipping suspend */
+	case SNDRV_PCM_STATE_OPEN:
+	case SNDRV_PCM_STATE_SETUP:
+	case SNDRV_PCM_STATE_DISCONNECTED:
+		return -EBUSY;
+	}
+	runtime->trigger_master = substream;
+	return 0;
+}
+
+static int snd_pcm_do_suspend(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (runtime->trigger_master != substream)
+		return 0;
+	if (! snd_pcm_running(substream))
+		return 0;
+	substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_SUSPEND);
+	return 0; /* suspend unconditionally */
+}
+
+static void snd_pcm_post_suspend(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_trigger_tstamp(substream);
+	runtime->status->suspended_state = runtime->status->state;
+	runtime->status->state = SNDRV_PCM_STATE_SUSPENDED;
+	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSUSPEND);
+	wake_up(&runtime->sleep);
+	wake_up(&runtime->tsleep);
+}
+
+static const struct action_ops snd_pcm_action_suspend = {
+	.pre_action = snd_pcm_pre_suspend,
+	.do_action = snd_pcm_do_suspend,
+	.post_action = snd_pcm_post_suspend
+};
+
+/**
+ * snd_pcm_suspend - trigger SUSPEND to all linked streams
+ * @substream: the PCM substream
+ *
+ * After this call, all streams are changed to SUSPENDED state.
+ *
+ * Return: Zero if successful (or @substream is %NULL), or a negative error
+ * code.
+ */
+int snd_pcm_suspend(struct snd_pcm_substream *substream)
+{
+	int err;
+	unsigned long flags;
+
+	if (! substream)
+		return 0;
+
+	snd_pcm_stream_lock_irqsave(substream, flags);
+	err = snd_pcm_action(&snd_pcm_action_suspend, substream, 0);
+	snd_pcm_stream_unlock_irqrestore(substream, flags);
+	return err;
+}
+EXPORT_SYMBOL(snd_pcm_suspend);
+
+/**
+ * snd_pcm_suspend_all - trigger SUSPEND to all substreams in the given pcm
+ * @pcm: the PCM instance
+ *
+ * After this call, all streams are changed to SUSPENDED state.
+ *
+ * Return: Zero if successful (or @pcm is %NULL), or a negative error code.
+ */
+int snd_pcm_suspend_all(struct snd_pcm *pcm)
+{
+	struct snd_pcm_substream *substream;
+	int stream, err = 0;
+
+	if (! pcm)
+		return 0;
+
+	for (stream = 0; stream < 2; stream++) {
+		for (substream = pcm->streams[stream].substream;
+		     substream; substream = substream->next) {
+			/* FIXME: the open/close code should lock this as well */
+			if (substream->runtime == NULL)
+				continue;
+
+			/*
+			 * Skip BE dai link PCM's that are internal and may
+			 * not have their substream ops set.
+			 */
+			if (!substream->ops)
+				continue;
+
+			err = snd_pcm_suspend(substream);
+			if (err < 0 && err != -EBUSY)
+				return err;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(snd_pcm_suspend_all);
+
+/* resume */
+
+static int snd_pcm_pre_resume(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (!(runtime->info & SNDRV_PCM_INFO_RESUME))
+		return -ENOSYS;
+	runtime->trigger_master = substream;
+	return 0;
+}
+
+static int snd_pcm_do_resume(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (runtime->trigger_master != substream)
+		return 0;
+	/* DMA not running previously? */
+	if (runtime->status->suspended_state != SNDRV_PCM_STATE_RUNNING &&
+	    (runtime->status->suspended_state != SNDRV_PCM_STATE_DRAINING ||
+	     substream->stream != SNDRV_PCM_STREAM_PLAYBACK))
+		return 0;
+	return substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_RESUME);
+}
+
+static void snd_pcm_undo_resume(struct snd_pcm_substream *substream, int state)
+{
+	if (substream->runtime->trigger_master == substream &&
+	    snd_pcm_running(substream))
+		substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_SUSPEND);
+}
+
+static void snd_pcm_post_resume(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_trigger_tstamp(substream);
+	runtime->status->state = runtime->status->suspended_state;
+	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MRESUME);
+}
+
+static const struct action_ops snd_pcm_action_resume = {
+	.pre_action = snd_pcm_pre_resume,
+	.do_action = snd_pcm_do_resume,
+	.undo_action = snd_pcm_undo_resume,
+	.post_action = snd_pcm_post_resume
+};
+
+static int snd_pcm_resume(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_action_lock_irq(&snd_pcm_action_resume, substream, 0);
+}
+
+#else
+
+static int snd_pcm_resume(struct snd_pcm_substream *substream)
+{
+	return -ENOSYS;
+}
+
+#endif /* CONFIG_PM */
+
+/*
+ * xrun ioctl
+ *
+ * Change the RUNNING stream(s) to XRUN state.
+ */
+static int snd_pcm_xrun(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	int result;
+
+	snd_pcm_stream_lock_irq(substream);
+	switch (runtime->status->state) {
+	case SNDRV_PCM_STATE_XRUN:
+		result = 0;	/* already there */
+		break;
+	case SNDRV_PCM_STATE_RUNNING:
+		__snd_pcm_xrun(substream);
+		result = 0;
+		break;
+	default:
+		result = -EBADFD;
+	}
+	snd_pcm_stream_unlock_irq(substream);
+	return result;
+}
+
+/*
+ * reset ioctl
+ */
+static int snd_pcm_pre_reset(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	switch (runtime->status->state) {
+	case SNDRV_PCM_STATE_RUNNING:
+	case SNDRV_PCM_STATE_PREPARED:
+	case SNDRV_PCM_STATE_PAUSED:
+	case SNDRV_PCM_STATE_SUSPENDED:
+		return 0;
+	default:
+		return -EBADFD;
+	}
+}
+
+static int snd_pcm_do_reset(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	int err = substream->ops->ioctl(substream, SNDRV_PCM_IOCTL1_RESET, NULL);
+	if (err < 0)
+		return err;
+	snd_pcm_stream_lock_irq(substream);
+	runtime->hw_ptr_base = 0;
+	runtime->hw_ptr_interrupt = runtime->status->hw_ptr -
+		runtime->status->hw_ptr % runtime->period_size;
+	runtime->silence_start = runtime->status->hw_ptr;
+	runtime->silence_filled = 0;
+	snd_pcm_stream_unlock_irq(substream);
+	return 0;
+}
+
+static void snd_pcm_post_reset(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_stream_lock_irq(substream);
+	runtime->control->appl_ptr = runtime->status->hw_ptr;
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
+	    runtime->silence_size > 0)
+		snd_pcm_playback_silence(substream, ULONG_MAX);
+	snd_pcm_stream_unlock_irq(substream);
+}
+
+static const struct action_ops snd_pcm_action_reset = {
+	.pre_action = snd_pcm_pre_reset,
+	.do_action = snd_pcm_do_reset,
+	.post_action = snd_pcm_post_reset
+};
+
+static int snd_pcm_reset(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_action_nonatomic(&snd_pcm_action_reset, substream, 0);
+}
+
+/*
+ * prepare ioctl
+ */
+/* we use the second argument for updating f_flags */
+static int snd_pcm_pre_prepare(struct snd_pcm_substream *substream,
+			       int f_flags)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
+	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
+		return -EBADFD;
+	if (snd_pcm_running(substream))
+		return -EBUSY;
+	substream->f_flags = f_flags;
+	return 0;
+}
+
+static int snd_pcm_do_prepare(struct snd_pcm_substream *substream, int state)
+{
+	int err;
+	err = substream->ops->prepare(substream);
+	if (err < 0)
+		return err;
+	return snd_pcm_do_reset(substream, 0);
+}
+
+static void snd_pcm_post_prepare(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	runtime->control->appl_ptr = runtime->status->hw_ptr;
+	snd_pcm_set_state(substream, SNDRV_PCM_STATE_PREPARED);
+}
+
+static const struct action_ops snd_pcm_action_prepare = {
+	.pre_action = snd_pcm_pre_prepare,
+	.do_action = snd_pcm_do_prepare,
+	.post_action = snd_pcm_post_prepare
+};
+
+/**
+ * snd_pcm_prepare - prepare the PCM substream to be triggerable
+ * @substream: the PCM substream instance
+ * @file: file to refer f_flags
+ *
+ * Return: Zero if successful, or a negative error code.
+ */
+static int snd_pcm_prepare(struct snd_pcm_substream *substream,
+			   struct file *file)
+{
+	int f_flags;
+
+	if (file)
+		f_flags = file->f_flags;
+	else
+		f_flags = substream->f_flags;
+
+	snd_pcm_stream_lock_irq(substream);
+	switch (substream->runtime->status->state) {
+	case SNDRV_PCM_STATE_PAUSED:
+		snd_pcm_pause(substream, 0);
+		/* fallthru */
+	case SNDRV_PCM_STATE_SUSPENDED:
+		snd_pcm_stop(substream, SNDRV_PCM_STATE_SETUP);
+		break;
+	}
+	snd_pcm_stream_unlock_irq(substream);
+
+	return snd_pcm_action_nonatomic(&snd_pcm_action_prepare,
+					substream, f_flags);
+}
+
+/*
+ * drain ioctl
+ */
+
+static int snd_pcm_pre_drain_init(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	switch (runtime->status->state) {
+	case SNDRV_PCM_STATE_OPEN:
+	case SNDRV_PCM_STATE_DISCONNECTED:
+	case SNDRV_PCM_STATE_SUSPENDED:
+		return -EBADFD;
+	}
+	runtime->trigger_master = substream;
+	return 0;
+}
+
+static int snd_pcm_do_drain_init(struct snd_pcm_substream *substream, int state)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		switch (runtime->status->state) {
+		case SNDRV_PCM_STATE_PREPARED:
+			/* start playback stream if possible */
+			if (! snd_pcm_playback_empty(substream)) {
+				snd_pcm_do_start(substream, SNDRV_PCM_STATE_DRAINING);
+				snd_pcm_post_start(substream, SNDRV_PCM_STATE_DRAINING);
+			} else {
+				runtime->status->state = SNDRV_PCM_STATE_SETUP;
+			}
+			break;
+		case SNDRV_PCM_STATE_RUNNING:
+			runtime->status->state = SNDRV_PCM_STATE_DRAINING;
+			break;
+		case SNDRV_PCM_STATE_XRUN:
+			runtime->status->state = SNDRV_PCM_STATE_SETUP;
+			break;
+		default:
+			break;
+		}
+	} else {
+		/* stop running stream */
+		if (runtime->status->state == SNDRV_PCM_STATE_RUNNING) {
+			int new_state = snd_pcm_capture_avail(runtime) > 0 ?
+				SNDRV_PCM_STATE_DRAINING : SNDRV_PCM_STATE_SETUP;
+			snd_pcm_do_stop(substream, new_state);
+			snd_pcm_post_stop(substream, new_state);
+		}
+	}
+
+	if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
+	    runtime->trigger_master == substream &&
+	    (runtime->hw.info & SNDRV_PCM_INFO_DRAIN_TRIGGER))
+		return substream->ops->trigger(substream,
+					       SNDRV_PCM_TRIGGER_DRAIN);
+
+	return 0;
+}
+
+static void snd_pcm_post_drain_init(struct snd_pcm_substream *substream, int state)
+{
+}
+
+static const struct action_ops snd_pcm_action_drain_init = {
+	.pre_action = snd_pcm_pre_drain_init,
+	.do_action = snd_pcm_do_drain_init,
+	.post_action = snd_pcm_post_drain_init
+};
+
+static int snd_pcm_drop(struct snd_pcm_substream *substream);
+
+/*
+ * Drain the stream(s).
+ * When the substream is linked, sync until the draining of all playback streams
+ * is finished.
+ * After this call, all streams are supposed to be either SETUP or DRAINING
+ * (capture only) state.
+ */
+static int snd_pcm_drain(struct snd_pcm_substream *substream,
+			 struct file *file)
+{
+	struct snd_card *card;
+	struct snd_pcm_runtime *runtime;
+	struct snd_pcm_substream *s;
+	wait_queue_entry_t wait;
+	int result = 0;
+	int nonblock = 0;
+
+	card = substream->pcm->card;
+	runtime = substream->runtime;
+
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+		return -EBADFD;
+
+	if (file) {
+		if (file->f_flags & O_NONBLOCK)
+			nonblock = 1;
+	} else if (substream->f_flags & O_NONBLOCK)
+		nonblock = 1;
+
+	down_read(&snd_pcm_link_rwsem);
+	snd_pcm_stream_lock_irq(substream);
+	/* resume pause */
+	if (runtime->status->state == SNDRV_PCM_STATE_PAUSED)
+		snd_pcm_pause(substream, 0);
+
+	/* pre-start/stop - all running streams are changed to DRAINING state */
+	result = snd_pcm_action(&snd_pcm_action_drain_init, substream, 0);
+	if (result < 0)
+		goto unlock;
+	/* in non-blocking, we don't wait in ioctl but let caller poll */
+	if (nonblock) {
+		result = -EAGAIN;
+		goto unlock;
+	}
+
+	for (;;) {
+		long tout;
+		struct snd_pcm_runtime *to_check;
+		if (signal_pending(current)) {
+			result = -ERESTARTSYS;
+			break;
+		}
+		/* find a substream to drain */
+		to_check = NULL;
+		snd_pcm_group_for_each_entry(s, substream) {
+			if (s->stream != SNDRV_PCM_STREAM_PLAYBACK)
+				continue;
+			runtime = s->runtime;
+			if (runtime->status->state == SNDRV_PCM_STATE_DRAINING) {
+				to_check = runtime;
+				break;
+			}
+		}
+		if (!to_check)
+			break; /* all drained */
+		init_waitqueue_entry(&wait, current);
+		add_wait_queue(&to_check->sleep, &wait);
+		snd_pcm_stream_unlock_irq(substream);
+		up_read(&snd_pcm_link_rwsem);
+		if (runtime->no_period_wakeup)
+			tout = MAX_SCHEDULE_TIMEOUT;
+		else {
+			tout = 10;
+			if (runtime->rate) {
+				long t = runtime->period_size * 2 / runtime->rate;
+				tout = max(t, tout);
+			}
+			tout = msecs_to_jiffies(tout * 1000);
+		}
+		tout = schedule_timeout_interruptible(tout);
+		down_read(&snd_pcm_link_rwsem);
+		snd_pcm_stream_lock_irq(substream);
+		remove_wait_queue(&to_check->sleep, &wait);
+		if (card->shutdown) {
+			result = -ENODEV;
+			break;
+		}
+		if (tout == 0) {
+			if (substream->runtime->status->state == SNDRV_PCM_STATE_SUSPENDED)
+				result = -ESTRPIPE;
+			else {
+				dev_dbg(substream->pcm->card->dev,
+					"playback drain error (DMA or IRQ trouble?)\n");
+				snd_pcm_stop(substream, SNDRV_PCM_STATE_SETUP);
+				result = -EIO;
+			}
+			break;
+		}
+	}
+
+ unlock:
+	snd_pcm_stream_unlock_irq(substream);
+	up_read(&snd_pcm_link_rwsem);
+
+	return result;
+}
+
+/*
+ * drop ioctl
+ *
+ * Immediately put all linked substreams into SETUP state.
+ */
+static int snd_pcm_drop(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime;
+	int result = 0;
+	
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+	runtime = substream->runtime;
+
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
+	    runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
+		return -EBADFD;
+
+	snd_pcm_stream_lock_irq(substream);
+	/* resume pause */
+	if (runtime->status->state == SNDRV_PCM_STATE_PAUSED)
+		snd_pcm_pause(substream, 0);
+
+	snd_pcm_stop(substream, SNDRV_PCM_STATE_SETUP);
+	/* runtime->control->appl_ptr = runtime->status->hw_ptr; */
+	snd_pcm_stream_unlock_irq(substream);
+
+	return result;
+}
+
+
+static bool is_pcm_file(struct file *file)
+{
+	struct inode *inode = file_inode(file);
+	unsigned int minor;
+
+	if (!S_ISCHR(inode->i_mode) || imajor(inode) != snd_major)
+		return false;
+	minor = iminor(inode);
+	return snd_lookup_minor_data(minor, SNDRV_DEVICE_TYPE_PCM_PLAYBACK) ||
+		snd_lookup_minor_data(minor, SNDRV_DEVICE_TYPE_PCM_CAPTURE);
+}
+
+/*
+ * PCM link handling
+ */
+static int snd_pcm_link(struct snd_pcm_substream *substream, int fd)
+{
+	int res = 0;
+	struct snd_pcm_file *pcm_file;
+	struct snd_pcm_substream *substream1;
+	struct snd_pcm_group *group;
+	struct fd f = fdget(fd);
+
+	if (!f.file)
+		return -EBADFD;
+	if (!is_pcm_file(f.file)) {
+		res = -EBADFD;
+		goto _badf;
+	}
+	pcm_file = f.file->private_data;
+	substream1 = pcm_file->substream;
+	if (substream == substream1) {
+		res = -EINVAL;
+		goto _badf;
+	}
+
+	group = kmalloc(sizeof(*group), GFP_KERNEL);
+	if (!group) {
+		res = -ENOMEM;
+		goto _nolock;
+	}
+	down_write_nonfifo(&snd_pcm_link_rwsem);
+	write_lock_irq(&snd_pcm_link_rwlock);
+	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN ||
+	    substream->runtime->status->state != substream1->runtime->status->state ||
+	    substream->pcm->nonatomic != substream1->pcm->nonatomic) {
+		res = -EBADFD;
+		goto _end;
+	}
+	if (snd_pcm_stream_linked(substream1)) {
+		res = -EALREADY;
+		goto _end;
+	}
+	if (!snd_pcm_stream_linked(substream)) {
+		substream->group = group;
+		group = NULL;
+		spin_lock_init(&substream->group->lock);
+		mutex_init(&substream->group->mutex);
+		INIT_LIST_HEAD(&substream->group->substreams);
+		list_add_tail(&substream->link_list, &substream->group->substreams);
+		substream->group->count = 1;
+	}
+	list_add_tail(&substream1->link_list, &substream->group->substreams);
+	substream->group->count++;
+	substream1->group = substream->group;
+ _end:
+	write_unlock_irq(&snd_pcm_link_rwlock);
+	up_write(&snd_pcm_link_rwsem);
+ _nolock:
+	snd_card_unref(substream1->pcm->card);
+	kfree(group);
+ _badf:
+	fdput(f);
+	return res;
+}
+
+static void relink_to_local(struct snd_pcm_substream *substream)
+{
+	substream->group = &substream->self_group;
+	INIT_LIST_HEAD(&substream->self_group.substreams);
+	list_add_tail(&substream->link_list, &substream->self_group.substreams);
+}
+
+static int snd_pcm_unlink(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_substream *s;
+	int res = 0;
+
+	down_write_nonfifo(&snd_pcm_link_rwsem);
+	write_lock_irq(&snd_pcm_link_rwlock);
+	if (!snd_pcm_stream_linked(substream)) {
+		res = -EALREADY;
+		goto _end;
+	}
+	list_del(&substream->link_list);
+	substream->group->count--;
+	if (substream->group->count == 1) {	/* detach the last stream, too */
+		snd_pcm_group_for_each_entry(s, substream) {
+			relink_to_local(s);
+			break;
+		}
+		kfree(substream->group);
+	}
+	relink_to_local(substream);
+       _end:
+	write_unlock_irq(&snd_pcm_link_rwlock);
+	up_write(&snd_pcm_link_rwsem);
+	return res;
+}
+
+/*
+ * hw configurator
+ */
+static int snd_pcm_hw_rule_mul(struct snd_pcm_hw_params *params,
+			       struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval t;
+	snd_interval_mul(hw_param_interval_c(params, rule->deps[0]),
+		     hw_param_interval_c(params, rule->deps[1]), &t);
+	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
+}
+
+static int snd_pcm_hw_rule_div(struct snd_pcm_hw_params *params,
+			       struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval t;
+	snd_interval_div(hw_param_interval_c(params, rule->deps[0]),
+		     hw_param_interval_c(params, rule->deps[1]), &t);
+	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
+}
+
+static int snd_pcm_hw_rule_muldivk(struct snd_pcm_hw_params *params,
+				   struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval t;
+	snd_interval_muldivk(hw_param_interval_c(params, rule->deps[0]),
+			 hw_param_interval_c(params, rule->deps[1]),
+			 (unsigned long) rule->private, &t);
+	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
+}
+
+static int snd_pcm_hw_rule_mulkdiv(struct snd_pcm_hw_params *params,
+				   struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval t;
+	snd_interval_mulkdiv(hw_param_interval_c(params, rule->deps[0]),
+			 (unsigned long) rule->private,
+			 hw_param_interval_c(params, rule->deps[1]), &t);
+	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
+}
+
+static int snd_pcm_hw_rule_format(struct snd_pcm_hw_params *params,
+				  struct snd_pcm_hw_rule *rule)
+{
+	unsigned int k;
+	const struct snd_interval *i =
+				hw_param_interval_c(params, rule->deps[0]);
+	struct snd_mask m;
+	struct snd_mask *mask = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
+	snd_mask_any(&m);
+	for (k = 0; k <= SNDRV_PCM_FORMAT_LAST; ++k) {
+		int bits;
+		if (! snd_mask_test(mask, k))
+			continue;
+		bits = snd_pcm_format_physical_width(k);
+		if (bits <= 0)
+			continue; /* ignore invalid formats */
+		if ((unsigned)bits < i->min || (unsigned)bits > i->max)
+			snd_mask_reset(&m, k);
+	}
+	return snd_mask_refine(mask, &m);
+}
+
+static int snd_pcm_hw_rule_sample_bits(struct snd_pcm_hw_params *params,
+				       struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval t;
+	unsigned int k;
+	t.min = UINT_MAX;
+	t.max = 0;
+	t.openmin = 0;
+	t.openmax = 0;
+	for (k = 0; k <= SNDRV_PCM_FORMAT_LAST; ++k) {
+		int bits;
+		if (! snd_mask_test(hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT), k))
+			continue;
+		bits = snd_pcm_format_physical_width(k);
+		if (bits <= 0)
+			continue; /* ignore invalid formats */
+		if (t.min > (unsigned)bits)
+			t.min = bits;
+		if (t.max < (unsigned)bits)
+			t.max = bits;
+	}
+	t.integer = 1;
+	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
+}
+
+#if SNDRV_PCM_RATE_5512 != 1 << 0 || SNDRV_PCM_RATE_192000 != 1 << 12
+#error "Change this table"
+#endif
+
+static const unsigned int rates[] = {
+	5512, 8000, 11025, 16000, 22050, 32000, 44100,
+	48000, 64000, 88200, 96000, 176400, 192000
+};
+
+const struct snd_pcm_hw_constraint_list snd_pcm_known_rates = {
+	.count = ARRAY_SIZE(rates),
+	.list = rates,
+};
+
+static int snd_pcm_hw_rule_rate(struct snd_pcm_hw_params *params,
+				struct snd_pcm_hw_rule *rule)
+{
+	struct snd_pcm_hardware *hw = rule->private;
+	return snd_interval_list(hw_param_interval(params, rule->var),
+				 snd_pcm_known_rates.count,
+				 snd_pcm_known_rates.list, hw->rates);
+}		
+
+static int snd_pcm_hw_rule_buffer_bytes_max(struct snd_pcm_hw_params *params,
+					    struct snd_pcm_hw_rule *rule)
+{
+	struct snd_interval t;
+	struct snd_pcm_substream *substream = rule->private;
+	t.min = 0;
+	t.max = substream->buffer_bytes_max;
+	t.openmin = 0;
+	t.openmax = 0;
+	t.integer = 1;
+	return snd_interval_refine(hw_param_interval(params, rule->var), &t);
+}		
+
+int snd_pcm_hw_constraints_init(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
+	int k, err;
+
+	for (k = SNDRV_PCM_HW_PARAM_FIRST_MASK; k <= SNDRV_PCM_HW_PARAM_LAST_MASK; k++) {
+		snd_mask_any(constrs_mask(constrs, k));
+	}
+
+	for (k = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++) {
+		snd_interval_any(constrs_interval(constrs, k));
+	}
+
+	snd_interval_setinteger(constrs_interval(constrs, SNDRV_PCM_HW_PARAM_CHANNELS));
+	snd_interval_setinteger(constrs_interval(constrs, SNDRV_PCM_HW_PARAM_BUFFER_SIZE));
+	snd_interval_setinteger(constrs_interval(constrs, SNDRV_PCM_HW_PARAM_BUFFER_BYTES));
+	snd_interval_setinteger(constrs_interval(constrs, SNDRV_PCM_HW_PARAM_SAMPLE_BITS));
+	snd_interval_setinteger(constrs_interval(constrs, SNDRV_PCM_HW_PARAM_FRAME_BITS));
+
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
+				   snd_pcm_hw_rule_format, NULL,
+				   SNDRV_PCM_HW_PARAM_SAMPLE_BITS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_SAMPLE_BITS, 
+				  snd_pcm_hw_rule_sample_bits, NULL,
+				  SNDRV_PCM_HW_PARAM_FORMAT, 
+				  SNDRV_PCM_HW_PARAM_SAMPLE_BITS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_SAMPLE_BITS, 
+				  snd_pcm_hw_rule_div, NULL,
+				  SNDRV_PCM_HW_PARAM_FRAME_BITS, SNDRV_PCM_HW_PARAM_CHANNELS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FRAME_BITS, 
+				  snd_pcm_hw_rule_mul, NULL,
+				  SNDRV_PCM_HW_PARAM_SAMPLE_BITS, SNDRV_PCM_HW_PARAM_CHANNELS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FRAME_BITS, 
+				  snd_pcm_hw_rule_mulkdiv, (void*) 8,
+				  SNDRV_PCM_HW_PARAM_PERIOD_BYTES, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FRAME_BITS, 
+				  snd_pcm_hw_rule_mulkdiv, (void*) 8,
+				  SNDRV_PCM_HW_PARAM_BUFFER_BYTES, SNDRV_PCM_HW_PARAM_BUFFER_SIZE, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS, 
+				  snd_pcm_hw_rule_div, NULL,
+				  SNDRV_PCM_HW_PARAM_FRAME_BITS, SNDRV_PCM_HW_PARAM_SAMPLE_BITS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE, 
+				  snd_pcm_hw_rule_mulkdiv, (void*) 1000000,
+				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, SNDRV_PCM_HW_PARAM_PERIOD_TIME, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE, 
+				  snd_pcm_hw_rule_mulkdiv, (void*) 1000000,
+				  SNDRV_PCM_HW_PARAM_BUFFER_SIZE, SNDRV_PCM_HW_PARAM_BUFFER_TIME, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIODS, 
+				  snd_pcm_hw_rule_div, NULL,
+				  SNDRV_PCM_HW_PARAM_BUFFER_SIZE, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 
+				  snd_pcm_hw_rule_div, NULL,
+				  SNDRV_PCM_HW_PARAM_BUFFER_SIZE, SNDRV_PCM_HW_PARAM_PERIODS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 
+				  snd_pcm_hw_rule_mulkdiv, (void*) 8,
+				  SNDRV_PCM_HW_PARAM_PERIOD_BYTES, SNDRV_PCM_HW_PARAM_FRAME_BITS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 
+				  snd_pcm_hw_rule_muldivk, (void*) 1000000,
+				  SNDRV_PCM_HW_PARAM_PERIOD_TIME, SNDRV_PCM_HW_PARAM_RATE, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 
+				  snd_pcm_hw_rule_mul, NULL,
+				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, SNDRV_PCM_HW_PARAM_PERIODS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 
+				  snd_pcm_hw_rule_mulkdiv, (void*) 8,
+				  SNDRV_PCM_HW_PARAM_BUFFER_BYTES, SNDRV_PCM_HW_PARAM_FRAME_BITS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 
+				  snd_pcm_hw_rule_muldivk, (void*) 1000000,
+				  SNDRV_PCM_HW_PARAM_BUFFER_TIME, SNDRV_PCM_HW_PARAM_RATE, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 
+				  snd_pcm_hw_rule_muldivk, (void*) 8,
+				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, SNDRV_PCM_HW_PARAM_FRAME_BITS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 
+				  snd_pcm_hw_rule_muldivk, (void*) 8,
+				  SNDRV_PCM_HW_PARAM_BUFFER_SIZE, SNDRV_PCM_HW_PARAM_FRAME_BITS, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_TIME, 
+				  snd_pcm_hw_rule_mulkdiv, (void*) 1000000,
+				  SNDRV_PCM_HW_PARAM_PERIOD_SIZE, SNDRV_PCM_HW_PARAM_RATE, -1);
+	if (err < 0)
+		return err;
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_TIME, 
+				  snd_pcm_hw_rule_mulkdiv, (void*) 1000000,
+				  SNDRV_PCM_HW_PARAM_BUFFER_SIZE, SNDRV_PCM_HW_PARAM_RATE, -1);
+	if (err < 0)
+		return err;
+	return 0;
+}
+
+int snd_pcm_hw_constraints_complete(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_pcm_hardware *hw = &runtime->hw;
+	int err;
+	unsigned int mask = 0;
+
+        if (hw->info & SNDRV_PCM_INFO_INTERLEAVED)
+		mask |= 1 << SNDRV_PCM_ACCESS_RW_INTERLEAVED;
+        if (hw->info & SNDRV_PCM_INFO_NONINTERLEAVED)
+		mask |= 1 << SNDRV_PCM_ACCESS_RW_NONINTERLEAVED;
+	if (hw_support_mmap(substream)) {
+		if (hw->info & SNDRV_PCM_INFO_INTERLEAVED)
+			mask |= 1 << SNDRV_PCM_ACCESS_MMAP_INTERLEAVED;
+		if (hw->info & SNDRV_PCM_INFO_NONINTERLEAVED)
+			mask |= 1 << SNDRV_PCM_ACCESS_MMAP_NONINTERLEAVED;
+		if (hw->info & SNDRV_PCM_INFO_COMPLEX)
+			mask |= 1 << SNDRV_PCM_ACCESS_MMAP_COMPLEX;
+	}
+	err = snd_pcm_hw_constraint_mask(runtime, SNDRV_PCM_HW_PARAM_ACCESS, mask);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_constraint_mask64(runtime, SNDRV_PCM_HW_PARAM_FORMAT, hw->formats);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_constraint_mask(runtime, SNDRV_PCM_HW_PARAM_SUBFORMAT, 1 << SNDRV_PCM_SUBFORMAT_STD);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_CHANNELS,
+					   hw->channels_min, hw->channels_max);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_RATE,
+					   hw->rate_min, hw->rate_max);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
+					   hw->period_bytes_min, hw->period_bytes_max);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIODS,
+					   hw->periods_min, hw->periods_max);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
+					   hw->period_bytes_min, hw->buffer_bytes_max);
+	if (err < 0)
+		return err;
+
+	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 
+				  snd_pcm_hw_rule_buffer_bytes_max, substream,
+				  SNDRV_PCM_HW_PARAM_BUFFER_BYTES, -1);
+	if (err < 0)
+		return err;
+
+	/* FIXME: remove */
+	if (runtime->dma_bytes) {
+		err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 0, runtime->dma_bytes);
+		if (err < 0)
+			return err;
+	}
+
+	if (!(hw->rates & (SNDRV_PCM_RATE_KNOT | SNDRV_PCM_RATE_CONTINUOUS))) {
+		err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE, 
+					  snd_pcm_hw_rule_rate, hw,
+					  SNDRV_PCM_HW_PARAM_RATE, -1);
+		if (err < 0)
+			return err;
+	}
+
+	/* FIXME: this belong to lowlevel */
+	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
+
+	return 0;
+}
+
+static void pcm_release_private(struct snd_pcm_substream *substream)
+{
+	if (snd_pcm_stream_linked(substream))
+		snd_pcm_unlink(substream);
+}
+
+void snd_pcm_release_substream(struct snd_pcm_substream *substream)
+{
+	substream->ref_count--;
+	if (substream->ref_count > 0)
+		return;
+
+	snd_pcm_drop(substream);
+	if (substream->hw_opened) {
+		if (substream->ops->hw_free &&
+		    substream->runtime->status->state != SNDRV_PCM_STATE_OPEN)
+			substream->ops->hw_free(substream);
+		substream->ops->close(substream);
+		substream->hw_opened = 0;
+	}
+	if (pm_qos_request_active(&substream->latency_pm_qos_req))
+		pm_qos_remove_request(&substream->latency_pm_qos_req);
+	if (substream->pcm_release) {
+		substream->pcm_release(substream);
+		substream->pcm_release = NULL;
+	}
+	snd_pcm_detach_substream(substream);
+}
+EXPORT_SYMBOL(snd_pcm_release_substream);
+
+int snd_pcm_open_substream(struct snd_pcm *pcm, int stream,
+			   struct file *file,
+			   struct snd_pcm_substream **rsubstream)
+{
+	struct snd_pcm_substream *substream;
+	int err;
+
+	err = snd_pcm_attach_substream(pcm, stream, file, &substream);
+	if (err < 0)
+		return err;
+	if (substream->ref_count > 1) {
+		*rsubstream = substream;
+		return 0;
+	}
+
+	err = snd_pcm_hw_constraints_init(substream);
+	if (err < 0) {
+		pcm_dbg(pcm, "snd_pcm_hw_constraints_init failed\n");
+		goto error;
+	}
+
+	if ((err = substream->ops->open(substream)) < 0)
+		goto error;
+
+	substream->hw_opened = 1;
+
+	err = snd_pcm_hw_constraints_complete(substream);
+	if (err < 0) {
+		pcm_dbg(pcm, "snd_pcm_hw_constraints_complete failed\n");
+		goto error;
+	}
+
+	*rsubstream = substream;
+	return 0;
+
+ error:
+	snd_pcm_release_substream(substream);
+	return err;
+}
+EXPORT_SYMBOL(snd_pcm_open_substream);
+
+static int snd_pcm_open_file(struct file *file,
+			     struct snd_pcm *pcm,
+			     int stream)
+{
+	struct snd_pcm_file *pcm_file;
+	struct snd_pcm_substream *substream;
+	int err;
+
+	err = snd_pcm_open_substream(pcm, stream, file, &substream);
+	if (err < 0)
+		return err;
+
+	pcm_file = kzalloc(sizeof(*pcm_file), GFP_KERNEL);
+	if (pcm_file == NULL) {
+		snd_pcm_release_substream(substream);
+		return -ENOMEM;
+	}
+	pcm_file->substream = substream;
+	if (substream->ref_count == 1) {
+		substream->file = pcm_file;
+		substream->pcm_release = pcm_release_private;
+	}
+	file->private_data = pcm_file;
+
+	return 0;
+}
+
+static int snd_pcm_playback_open(struct inode *inode, struct file *file)
+{
+	struct snd_pcm *pcm;
+	int err = nonseekable_open(inode, file);
+	if (err < 0)
+		return err;
+	pcm = snd_lookup_minor_data(iminor(inode),
+				    SNDRV_DEVICE_TYPE_PCM_PLAYBACK);
+	err = snd_pcm_open(file, pcm, SNDRV_PCM_STREAM_PLAYBACK);
+	if (pcm)
+		snd_card_unref(pcm->card);
+	return err;
+}
+
+static int snd_pcm_capture_open(struct inode *inode, struct file *file)
+{
+	struct snd_pcm *pcm;
+	int err = nonseekable_open(inode, file);
+	if (err < 0)
+		return err;
+	pcm = snd_lookup_minor_data(iminor(inode),
+				    SNDRV_DEVICE_TYPE_PCM_CAPTURE);
+	err = snd_pcm_open(file, pcm, SNDRV_PCM_STREAM_CAPTURE);
+	if (pcm)
+		snd_card_unref(pcm->card);
+	return err;
+}
+
+static int snd_pcm_open(struct file *file, struct snd_pcm *pcm, int stream)
+{
+	int err;
+	wait_queue_entry_t wait;
+
+	if (pcm == NULL) {
+		err = -ENODEV;
+		goto __error1;
+	}
+	err = snd_card_file_add(pcm->card, file);
+	if (err < 0)
+		goto __error1;
+	if (!try_module_get(pcm->card->module)) {
+		err = -EFAULT;
+		goto __error2;
+	}
+	init_waitqueue_entry(&wait, current);
+	add_wait_queue(&pcm->open_wait, &wait);
+	mutex_lock(&pcm->open_mutex);
+	while (1) {
+		err = snd_pcm_open_file(file, pcm, stream);
+		if (err >= 0)
+			break;
+		if (err == -EAGAIN) {
+			if (file->f_flags & O_NONBLOCK) {
+				err = -EBUSY;
+				break;
+			}
+		} else
+			break;
+		set_current_state(TASK_INTERRUPTIBLE);
+		mutex_unlock(&pcm->open_mutex);
+		schedule();
+		mutex_lock(&pcm->open_mutex);
+		if (pcm->card->shutdown) {
+			err = -ENODEV;
+			break;
+		}
+		if (signal_pending(current)) {
+			err = -ERESTARTSYS;
+			break;
+		}
+	}
+	remove_wait_queue(&pcm->open_wait, &wait);
+	mutex_unlock(&pcm->open_mutex);
+	if (err < 0)
+		goto __error;
+	return err;
+
+      __error:
+	module_put(pcm->card->module);
+      __error2:
+      	snd_card_file_remove(pcm->card, file);
+      __error1:
+      	return err;
+}
+
+static int snd_pcm_release(struct inode *inode, struct file *file)
+{
+	struct snd_pcm *pcm;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_file *pcm_file;
+
+	pcm_file = file->private_data;
+	substream = pcm_file->substream;
+	if (snd_BUG_ON(!substream))
+		return -ENXIO;
+	pcm = substream->pcm;
+	mutex_lock(&pcm->open_mutex);
+	snd_pcm_release_substream(substream);
+	kfree(pcm_file);
+	mutex_unlock(&pcm->open_mutex);
+	wake_up(&pcm->open_wait);
+	module_put(pcm->card->module);
+	snd_card_file_remove(pcm->card, file);
+	return 0;
+}
+
+/* check and update PCM state; return 0 or a negative error
+ * call this inside PCM lock
+ */
+static int do_pcm_hwsync(struct snd_pcm_substream *substream)
+{
+	switch (substream->runtime->status->state) {
+	case SNDRV_PCM_STATE_DRAINING:
+		if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
+			return -EBADFD;
+		/* Fall through */
+	case SNDRV_PCM_STATE_RUNNING:
+		return snd_pcm_update_hw_ptr(substream);
+	case SNDRV_PCM_STATE_PREPARED:
+	case SNDRV_PCM_STATE_PAUSED:
+		return 0;
+	case SNDRV_PCM_STATE_SUSPENDED:
+		return -ESTRPIPE;
+	case SNDRV_PCM_STATE_XRUN:
+		return -EPIPE;
+	default:
+		return -EBADFD;
+	}
+}
+
+/* increase the appl_ptr; returns the processed frames or a negative error */
+static snd_pcm_sframes_t forward_appl_ptr(struct snd_pcm_substream *substream,
+					  snd_pcm_uframes_t frames,
+					   snd_pcm_sframes_t avail)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_sframes_t appl_ptr;
+	int ret;
+
+	if (avail <= 0)
+		return 0;
+	if (frames > (snd_pcm_uframes_t)avail)
+		frames = avail;
+	appl_ptr = runtime->control->appl_ptr + frames;
+	if (appl_ptr >= (snd_pcm_sframes_t)runtime->boundary)
+		appl_ptr -= runtime->boundary;
+	ret = pcm_lib_apply_appl_ptr(substream, appl_ptr);
+	return ret < 0 ? ret : frames;
+}
+
+/* decrease the appl_ptr; returns the processed frames or zero for error */
+static snd_pcm_sframes_t rewind_appl_ptr(struct snd_pcm_substream *substream,
+					 snd_pcm_uframes_t frames,
+					 snd_pcm_sframes_t avail)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_sframes_t appl_ptr;
+	int ret;
+
+	if (avail <= 0)
+		return 0;
+	if (frames > (snd_pcm_uframes_t)avail)
+		frames = avail;
+	appl_ptr = runtime->control->appl_ptr - frames;
+	if (appl_ptr < 0)
+		appl_ptr += runtime->boundary;
+	ret = pcm_lib_apply_appl_ptr(substream, appl_ptr);
+	/* NOTE: we return zero for errors because PulseAudio gets depressed
+	 * upon receiving an error from rewind ioctl and stops processing
+	 * any longer.  Returning zero means that no rewind is done, so
+	 * it's not absolutely wrong to answer like that.
+	 */
+	return ret < 0 ? 0 : frames;
+}
+
+static snd_pcm_sframes_t snd_pcm_rewind(struct snd_pcm_substream *substream,
+					snd_pcm_uframes_t frames)
+{
+	snd_pcm_sframes_t ret;
+
+	if (frames == 0)
+		return 0;
+
+	snd_pcm_stream_lock_irq(substream);
+	ret = do_pcm_hwsync(substream);
+	if (!ret)
+		ret = rewind_appl_ptr(substream, frames,
+				      snd_pcm_hw_avail(substream));
+	snd_pcm_stream_unlock_irq(substream);
+	return ret;
+}
+
+static snd_pcm_sframes_t snd_pcm_forward(struct snd_pcm_substream *substream,
+					 snd_pcm_uframes_t frames)
+{
+	snd_pcm_sframes_t ret;
+
+	if (frames == 0)
+		return 0;
+
+	snd_pcm_stream_lock_irq(substream);
+	ret = do_pcm_hwsync(substream);
+	if (!ret)
+		ret = forward_appl_ptr(substream, frames,
+				       snd_pcm_avail(substream));
+	snd_pcm_stream_unlock_irq(substream);
+	return ret;
+}
+
+static int snd_pcm_hwsync(struct snd_pcm_substream *substream)
+{
+	int err;
+
+	snd_pcm_stream_lock_irq(substream);
+	err = do_pcm_hwsync(substream);
+	snd_pcm_stream_unlock_irq(substream);
+	return err;
+}
+		
+static int snd_pcm_delay(struct snd_pcm_substream *substream,
+			 snd_pcm_sframes_t *delay)
+{
+	int err;
+	snd_pcm_sframes_t n = 0;
+
+	snd_pcm_stream_lock_irq(substream);
+	err = do_pcm_hwsync(substream);
+	if (!err)
+		n = snd_pcm_calc_delay(substream);
+	snd_pcm_stream_unlock_irq(substream);
+	if (!err)
+		*delay = n;
+	return err;
+}
+		
+static int snd_pcm_sync_ptr(struct snd_pcm_substream *substream,
+			    struct snd_pcm_sync_ptr __user *_sync_ptr)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_pcm_sync_ptr sync_ptr;
+	volatile struct snd_pcm_mmap_status *status;
+	volatile struct snd_pcm_mmap_control *control;
+	int err;
+
+	memset(&sync_ptr, 0, sizeof(sync_ptr));
+	if (get_user(sync_ptr.flags, (unsigned __user *)&(_sync_ptr->flags)))
+		return -EFAULT;
+	if (copy_from_user(&sync_ptr.c.control, &(_sync_ptr->c.control), sizeof(struct snd_pcm_mmap_control)))
+		return -EFAULT;	
+	status = runtime->status;
+	control = runtime->control;
+	if (sync_ptr.flags & SNDRV_PCM_SYNC_PTR_HWSYNC) {
+		err = snd_pcm_hwsync(substream);
+		if (err < 0)
+			return err;
+	}
+	snd_pcm_stream_lock_irq(substream);
+	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL)) {
+		err = pcm_lib_apply_appl_ptr(substream,
+					     sync_ptr.c.control.appl_ptr);
+		if (err < 0) {
+			snd_pcm_stream_unlock_irq(substream);
+			return err;
+		}
+	} else {
+		sync_ptr.c.control.appl_ptr = control->appl_ptr;
+	}
+	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
+		control->avail_min = sync_ptr.c.control.avail_min;
+	else
+		sync_ptr.c.control.avail_min = control->avail_min;
+	sync_ptr.s.status.state = status->state;
+	sync_ptr.s.status.hw_ptr = status->hw_ptr;
+	sync_ptr.s.status.tstamp = status->tstamp;
+	sync_ptr.s.status.suspended_state = status->suspended_state;
+	sync_ptr.s.status.audio_tstamp = status->audio_tstamp;
+	snd_pcm_stream_unlock_irq(substream);
+	if (copy_to_user(_sync_ptr, &sync_ptr, sizeof(sync_ptr)))
+		return -EFAULT;
+	return 0;
+}
+
+static int snd_pcm_tstamp(struct snd_pcm_substream *substream, int __user *_arg)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	int arg;
+	
+	if (get_user(arg, _arg))
+		return -EFAULT;
+	if (arg < 0 || arg > SNDRV_PCM_TSTAMP_TYPE_LAST)
+		return -EINVAL;
+	runtime->tstamp_type = arg;
+	return 0;
+}
+
+static int snd_pcm_xferi_frames_ioctl(struct snd_pcm_substream *substream,
+				      struct snd_xferi __user *_xferi)
+{
+	struct snd_xferi xferi;
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_sframes_t result;
+
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+		return -EBADFD;
+	if (put_user(0, &_xferi->result))
+		return -EFAULT;
+	if (copy_from_user(&xferi, _xferi, sizeof(xferi)))
+		return -EFAULT;
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		result = snd_pcm_lib_write(substream, xferi.buf, xferi.frames);
+	else
+		result = snd_pcm_lib_read(substream, xferi.buf, xferi.frames);
+	__put_user(result, &_xferi->result);
+	return result < 0 ? result : 0;
+}
+
+static int snd_pcm_xfern_frames_ioctl(struct snd_pcm_substream *substream,
+				      struct snd_xfern __user *_xfern)
+{
+	struct snd_xfern xfern;
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	void *bufs;
+	snd_pcm_sframes_t result;
+
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+		return -EBADFD;
+	if (runtime->channels > 128)
+		return -EINVAL;
+	if (put_user(0, &_xfern->result))
+		return -EFAULT;
+	if (copy_from_user(&xfern, _xfern, sizeof(xfern)))
+		return -EFAULT;
+
+	bufs = memdup_user(xfern.bufs, sizeof(void *) * runtime->channels);
+	if (IS_ERR(bufs))
+		return PTR_ERR(bufs);
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		result = snd_pcm_lib_writev(substream, bufs, xfern.frames);
+	else
+		result = snd_pcm_lib_readv(substream, bufs, xfern.frames);
+	kfree(bufs);
+	__put_user(result, &_xfern->result);
+	return result < 0 ? result : 0;
+}
+
+static int snd_pcm_rewind_ioctl(struct snd_pcm_substream *substream,
+				snd_pcm_uframes_t __user *_frames)
+{
+	snd_pcm_uframes_t frames;
+	snd_pcm_sframes_t result;
+
+	if (get_user(frames, _frames))
+		return -EFAULT;
+	if (put_user(0, _frames))
+		return -EFAULT;
+	result = snd_pcm_rewind(substream, frames);
+	__put_user(result, _frames);
+	return result < 0 ? result : 0;
+}
+
+static int snd_pcm_forward_ioctl(struct snd_pcm_substream *substream,
+				 snd_pcm_uframes_t __user *_frames)
+{
+	snd_pcm_uframes_t frames;
+	snd_pcm_sframes_t result;
+
+	if (get_user(frames, _frames))
+		return -EFAULT;
+	if (put_user(0, _frames))
+		return -EFAULT;
+	result = snd_pcm_forward(substream, frames);
+	__put_user(result, _frames);
+	return result < 0 ? result : 0;
+}
+
+static int snd_pcm_common_ioctl(struct file *file,
+				 struct snd_pcm_substream *substream,
+				 unsigned int cmd, void __user *arg)
+{
+	struct snd_pcm_file *pcm_file = file->private_data;
+	int res;
+
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+
+	res = snd_power_wait(substream->pcm->card, SNDRV_CTL_POWER_D0);
+	if (res < 0)
+		return res;
+
+	switch (cmd) {
+	case SNDRV_PCM_IOCTL_PVERSION:
+		return put_user(SNDRV_PCM_VERSION, (int __user *)arg) ? -EFAULT : 0;
+	case SNDRV_PCM_IOCTL_INFO:
+		return snd_pcm_info_user(substream, arg);
+	case SNDRV_PCM_IOCTL_TSTAMP:	/* just for compatibility */
+		return 0;
+	case SNDRV_PCM_IOCTL_TTSTAMP:
+		return snd_pcm_tstamp(substream, arg);
+	case SNDRV_PCM_IOCTL_USER_PVERSION:
+		if (get_user(pcm_file->user_pversion,
+			     (unsigned int __user *)arg))
+			return -EFAULT;
+		return 0;
+	case SNDRV_PCM_IOCTL_HW_REFINE:
+		return snd_pcm_hw_refine_user(substream, arg);
+	case SNDRV_PCM_IOCTL_HW_PARAMS:
+		return snd_pcm_hw_params_user(substream, arg);
+	case SNDRV_PCM_IOCTL_HW_FREE:
+		return snd_pcm_hw_free(substream);
+	case SNDRV_PCM_IOCTL_SW_PARAMS:
+		return snd_pcm_sw_params_user(substream, arg);
+	case SNDRV_PCM_IOCTL_STATUS:
+		return snd_pcm_status_user(substream, arg, false);
+	case SNDRV_PCM_IOCTL_STATUS_EXT:
+		return snd_pcm_status_user(substream, arg, true);
+	case SNDRV_PCM_IOCTL_CHANNEL_INFO:
+		return snd_pcm_channel_info_user(substream, arg);
+	case SNDRV_PCM_IOCTL_PREPARE:
+		return snd_pcm_prepare(substream, file);
+	case SNDRV_PCM_IOCTL_RESET:
+		return snd_pcm_reset(substream);
+	case SNDRV_PCM_IOCTL_START:
+		return snd_pcm_start_lock_irq(substream);
+	case SNDRV_PCM_IOCTL_LINK:
+		return snd_pcm_link(substream, (int)(unsigned long) arg);
+	case SNDRV_PCM_IOCTL_UNLINK:
+		return snd_pcm_unlink(substream);
+	case SNDRV_PCM_IOCTL_RESUME:
+		return snd_pcm_resume(substream);
+	case SNDRV_PCM_IOCTL_XRUN:
+		return snd_pcm_xrun(substream);
+	case SNDRV_PCM_IOCTL_HWSYNC:
+		return snd_pcm_hwsync(substream);
+	case SNDRV_PCM_IOCTL_DELAY:
+	{
+		snd_pcm_sframes_t delay;
+		snd_pcm_sframes_t __user *res = arg;
+		int err;
+
+		err = snd_pcm_delay(substream, &delay);
+		if (err)
+			return err;
+		if (put_user(delay, res))
+			return -EFAULT;
+		return 0;
+	}
+	case SNDRV_PCM_IOCTL_SYNC_PTR:
+		return snd_pcm_sync_ptr(substream, arg);
+#ifdef CONFIG_SND_SUPPORT_OLD_API
+	case SNDRV_PCM_IOCTL_HW_REFINE_OLD:
+		return snd_pcm_hw_refine_old_user(substream, arg);
+	case SNDRV_PCM_IOCTL_HW_PARAMS_OLD:
+		return snd_pcm_hw_params_old_user(substream, arg);
+#endif
+	case SNDRV_PCM_IOCTL_DRAIN:
+		return snd_pcm_drain(substream, file);
+	case SNDRV_PCM_IOCTL_DROP:
+		return snd_pcm_drop(substream);
+	case SNDRV_PCM_IOCTL_PAUSE:
+		return snd_pcm_action_lock_irq(&snd_pcm_action_pause,
+					       substream,
+					       (int)(unsigned long)arg);
+	case SNDRV_PCM_IOCTL_WRITEI_FRAMES:
+	case SNDRV_PCM_IOCTL_READI_FRAMES:
+		return snd_pcm_xferi_frames_ioctl(substream, arg);
+	case SNDRV_PCM_IOCTL_WRITEN_FRAMES:
+	case SNDRV_PCM_IOCTL_READN_FRAMES:
+		return snd_pcm_xfern_frames_ioctl(substream, arg);
+	case SNDRV_PCM_IOCTL_REWIND:
+		return snd_pcm_rewind_ioctl(substream, arg);
+	case SNDRV_PCM_IOCTL_FORWARD:
+		return snd_pcm_forward_ioctl(substream, arg);
+	}
+	pcm_dbg(substream->pcm, "unknown ioctl = 0x%x\n", cmd);
+	return -ENOTTY;
+}
+
+static long snd_pcm_ioctl(struct file *file, unsigned int cmd,
+			  unsigned long arg)
+{
+	struct snd_pcm_file *pcm_file;
+
+	pcm_file = file->private_data;
+
+	if (((cmd >> 8) & 0xff) != 'A')
+		return -ENOTTY;
+
+	return snd_pcm_common_ioctl(file, pcm_file->substream, cmd,
+				     (void __user *)arg);
+}
+
+/**
+ * snd_pcm_kernel_ioctl - Execute PCM ioctl in the kernel-space
+ * @substream: PCM substream
+ * @cmd: IOCTL cmd
+ * @arg: IOCTL argument
+ *
+ * The function is provided primarily for OSS layer and USB gadget drivers,
+ * and it allows only the limited set of ioctls (hw_params, sw_params,
+ * prepare, start, drain, drop, forward).
+ */
+int snd_pcm_kernel_ioctl(struct snd_pcm_substream *substream,
+			 unsigned int cmd, void *arg)
+{
+	snd_pcm_uframes_t *frames = arg;
+	snd_pcm_sframes_t result;
+	
+	switch (cmd) {
+	case SNDRV_PCM_IOCTL_FORWARD:
+	{
+		/* provided only for OSS; capture-only and no value returned */
+		if (substream->stream != SNDRV_PCM_STREAM_CAPTURE)
+			return -EINVAL;
+		result = snd_pcm_forward(substream, *frames);
+		return result < 0 ? result : 0;
+	}
+	case SNDRV_PCM_IOCTL_HW_PARAMS:
+		return snd_pcm_hw_params(substream, arg);
+	case SNDRV_PCM_IOCTL_SW_PARAMS:
+		return snd_pcm_sw_params(substream, arg);
+	case SNDRV_PCM_IOCTL_PREPARE:
+		return snd_pcm_prepare(substream, NULL);
+	case SNDRV_PCM_IOCTL_START:
+		return snd_pcm_start_lock_irq(substream);
+	case SNDRV_PCM_IOCTL_DRAIN:
+		return snd_pcm_drain(substream, NULL);
+	case SNDRV_PCM_IOCTL_DROP:
+		return snd_pcm_drop(substream);
+	case SNDRV_PCM_IOCTL_DELAY:
+		return snd_pcm_delay(substream, frames);
+	default:
+		return -EINVAL;
+	}
+}
+EXPORT_SYMBOL(snd_pcm_kernel_ioctl);
+
+static ssize_t snd_pcm_read(struct file *file, char __user *buf, size_t count,
+			    loff_t * offset)
+{
+	struct snd_pcm_file *pcm_file;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	snd_pcm_sframes_t result;
+
+	pcm_file = file->private_data;
+	substream = pcm_file->substream;
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+	runtime = substream->runtime;
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+		return -EBADFD;
+	if (!frame_aligned(runtime, count))
+		return -EINVAL;
+	count = bytes_to_frames(runtime, count);
+	result = snd_pcm_lib_read(substream, buf, count);
+	if (result > 0)
+		result = frames_to_bytes(runtime, result);
+	return result;
+}
+
+static ssize_t snd_pcm_write(struct file *file, const char __user *buf,
+			     size_t count, loff_t * offset)
+{
+	struct snd_pcm_file *pcm_file;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	snd_pcm_sframes_t result;
+
+	pcm_file = file->private_data;
+	substream = pcm_file->substream;
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+	runtime = substream->runtime;
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+		return -EBADFD;
+	if (!frame_aligned(runtime, count))
+		return -EINVAL;
+	count = bytes_to_frames(runtime, count);
+	result = snd_pcm_lib_write(substream, buf, count);
+	if (result > 0)
+		result = frames_to_bytes(runtime, result);
+	return result;
+}
+
+static ssize_t snd_pcm_readv(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct snd_pcm_file *pcm_file;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	snd_pcm_sframes_t result;
+	unsigned long i;
+	void __user **bufs;
+	snd_pcm_uframes_t frames;
+
+	pcm_file = iocb->ki_filp->private_data;
+	substream = pcm_file->substream;
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+	runtime = substream->runtime;
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+		return -EBADFD;
+	if (!iter_is_iovec(to))
+		return -EINVAL;
+	if (to->nr_segs > 1024 || to->nr_segs != runtime->channels)
+		return -EINVAL;
+	if (!frame_aligned(runtime, to->iov->iov_len))
+		return -EINVAL;
+	frames = bytes_to_samples(runtime, to->iov->iov_len);
+	bufs = kmalloc_array(to->nr_segs, sizeof(void *), GFP_KERNEL);
+	if (bufs == NULL)
+		return -ENOMEM;
+	for (i = 0; i < to->nr_segs; ++i)
+		bufs[i] = to->iov[i].iov_base;
+	result = snd_pcm_lib_readv(substream, bufs, frames);
+	if (result > 0)
+		result = frames_to_bytes(runtime, result);
+	kfree(bufs);
+	return result;
+}
+
+static ssize_t snd_pcm_writev(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct snd_pcm_file *pcm_file;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	snd_pcm_sframes_t result;
+	unsigned long i;
+	void __user **bufs;
+	snd_pcm_uframes_t frames;
+
+	pcm_file = iocb->ki_filp->private_data;
+	substream = pcm_file->substream;
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+	runtime = substream->runtime;
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+		return -EBADFD;
+	if (!iter_is_iovec(from))
+		return -EINVAL;
+	if (from->nr_segs > 128 || from->nr_segs != runtime->channels ||
+	    !frame_aligned(runtime, from->iov->iov_len))
+		return -EINVAL;
+	frames = bytes_to_samples(runtime, from->iov->iov_len);
+	bufs = kmalloc_array(from->nr_segs, sizeof(void *), GFP_KERNEL);
+	if (bufs == NULL)
+		return -ENOMEM;
+	for (i = 0; i < from->nr_segs; ++i)
+		bufs[i] = from->iov[i].iov_base;
+	result = snd_pcm_lib_writev(substream, bufs, frames);
+	if (result > 0)
+		result = frames_to_bytes(runtime, result);
+	kfree(bufs);
+	return result;
+}
+
+static __poll_t snd_pcm_poll(struct file *file, poll_table *wait)
+{
+	struct snd_pcm_file *pcm_file;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	__poll_t mask, ok;
+	snd_pcm_uframes_t avail;
+
+	pcm_file = file->private_data;
+
+	substream = pcm_file->substream;
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		ok = EPOLLOUT | EPOLLWRNORM;
+	else
+		ok = EPOLLIN | EPOLLRDNORM;
+	if (PCM_RUNTIME_CHECK(substream))
+		return ok | EPOLLERR;
+
+	runtime = substream->runtime;
+	poll_wait(file, &runtime->sleep, wait);
+
+	mask = 0;
+	snd_pcm_stream_lock_irq(substream);
+	avail = snd_pcm_avail(substream);
+	switch (runtime->status->state) {
+	case SNDRV_PCM_STATE_RUNNING:
+	case SNDRV_PCM_STATE_PREPARED:
+	case SNDRV_PCM_STATE_PAUSED:
+		if (avail >= runtime->control->avail_min)
+			mask = ok;
+		break;
+	case SNDRV_PCM_STATE_DRAINING:
+		if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
+			mask = ok;
+			if (!avail)
+				mask |= EPOLLERR;
+		}
+		break;
+	default:
+		mask = ok | EPOLLERR;
+		break;
+	}
+	snd_pcm_stream_unlock_irq(substream);
+	return mask;
+}
+
+/*
+ * mmap support
+ */
+
+/*
+ * Only on coherent architectures, we can mmap the status and the control records
+ * for effcient data transfer.  On others, we have to use HWSYNC ioctl...
+ */
+#if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_ALPHA)
+/*
+ * mmap status record
+ */
+static vm_fault_t snd_pcm_mmap_status_fault(struct vm_fault *vmf)
+{
+	struct snd_pcm_substream *substream = vmf->vma->vm_private_data;
+	struct snd_pcm_runtime *runtime;
+	
+	if (substream == NULL)
+		return VM_FAULT_SIGBUS;
+	runtime = substream->runtime;
+	vmf->page = virt_to_page(runtime->status);
+	get_page(vmf->page);
+	return 0;
+}
+
+static const struct vm_operations_struct snd_pcm_vm_ops_status =
+{
+	.fault =	snd_pcm_mmap_status_fault,
+};
+
+static int snd_pcm_mmap_status(struct snd_pcm_substream *substream, struct file *file,
+			       struct vm_area_struct *area)
+{
+	long size;
+	if (!(area->vm_flags & VM_READ))
+		return -EINVAL;
+	size = area->vm_end - area->vm_start;
+	if (size != PAGE_ALIGN(sizeof(struct snd_pcm_mmap_status)))
+		return -EINVAL;
+	area->vm_ops = &snd_pcm_vm_ops_status;
+	area->vm_private_data = substream;
+	area->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
+	return 0;
+}
+
+/*
+ * mmap control record
+ */
+static vm_fault_t snd_pcm_mmap_control_fault(struct vm_fault *vmf)
+{
+	struct snd_pcm_substream *substream = vmf->vma->vm_private_data;
+	struct snd_pcm_runtime *runtime;
+	
+	if (substream == NULL)
+		return VM_FAULT_SIGBUS;
+	runtime = substream->runtime;
+	vmf->page = virt_to_page(runtime->control);
+	get_page(vmf->page);
+	return 0;
+}
+
+static const struct vm_operations_struct snd_pcm_vm_ops_control =
+{
+	.fault =	snd_pcm_mmap_control_fault,
+};
+
+static int snd_pcm_mmap_control(struct snd_pcm_substream *substream, struct file *file,
+				struct vm_area_struct *area)
+{
+	long size;
+	if (!(area->vm_flags & VM_READ))
+		return -EINVAL;
+	size = area->vm_end - area->vm_start;
+	if (size != PAGE_ALIGN(sizeof(struct snd_pcm_mmap_control)))
+		return -EINVAL;
+	area->vm_ops = &snd_pcm_vm_ops_control;
+	area->vm_private_data = substream;
+	area->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
+	return 0;
+}
+
+static bool pcm_status_mmap_allowed(struct snd_pcm_file *pcm_file)
+{
+	if (pcm_file->no_compat_mmap)
+		return false;
+	/* See pcm_control_mmap_allowed() below.
+	 * Since older alsa-lib requires both status and control mmaps to be
+	 * coupled, we have to disable the status mmap for old alsa-lib, too.
+	 */
+	if (pcm_file->user_pversion < SNDRV_PROTOCOL_VERSION(2, 0, 14) &&
+	    (pcm_file->substream->runtime->hw.info & SNDRV_PCM_INFO_SYNC_APPLPTR))
+		return false;
+	return true;
+}
+
+static bool pcm_control_mmap_allowed(struct snd_pcm_file *pcm_file)
+{
+	if (pcm_file->no_compat_mmap)
+		return false;
+	/* Disallow the control mmap when SYNC_APPLPTR flag is set;
+	 * it enforces the user-space to fall back to snd_pcm_sync_ptr(),
+	 * thus it effectively assures the manual update of appl_ptr.
+	 */
+	if (pcm_file->substream->runtime->hw.info & SNDRV_PCM_INFO_SYNC_APPLPTR)
+		return false;
+	return true;
+}
+
+#else /* ! coherent mmap */
+/*
+ * don't support mmap for status and control records.
+ */
+#define pcm_status_mmap_allowed(pcm_file)	false
+#define pcm_control_mmap_allowed(pcm_file)	false
+
+static int snd_pcm_mmap_status(struct snd_pcm_substream *substream, struct file *file,
+			       struct vm_area_struct *area)
+{
+	return -ENXIO;
+}
+static int snd_pcm_mmap_control(struct snd_pcm_substream *substream, struct file *file,
+				struct vm_area_struct *area)
+{
+	return -ENXIO;
+}
+#endif /* coherent mmap */
+
+static inline struct page *
+snd_pcm_default_page_ops(struct snd_pcm_substream *substream, unsigned long ofs)
+{
+	void *vaddr = substream->runtime->dma_area + ofs;
+	return virt_to_page(vaddr);
+}
+
+/*
+ * fault callback for mmapping a RAM page
+ */
+static vm_fault_t snd_pcm_mmap_data_fault(struct vm_fault *vmf)
+{
+	struct snd_pcm_substream *substream = vmf->vma->vm_private_data;
+	struct snd_pcm_runtime *runtime;
+	unsigned long offset;
+	struct page * page;
+	size_t dma_bytes;
+	
+	if (substream == NULL)
+		return VM_FAULT_SIGBUS;
+	runtime = substream->runtime;
+	offset = vmf->pgoff << PAGE_SHIFT;
+	dma_bytes = PAGE_ALIGN(runtime->dma_bytes);
+	if (offset > dma_bytes - PAGE_SIZE)
+		return VM_FAULT_SIGBUS;
+	if (substream->ops->page)
+		page = substream->ops->page(substream, offset);
+	else
+		page = snd_pcm_default_page_ops(substream, offset);
+	if (!page)
+		return VM_FAULT_SIGBUS;
+	get_page(page);
+	vmf->page = page;
+	return 0;
+}
+
+static const struct vm_operations_struct snd_pcm_vm_ops_data = {
+	.open =		snd_pcm_mmap_data_open,
+	.close =	snd_pcm_mmap_data_close,
+};
+
+static const struct vm_operations_struct snd_pcm_vm_ops_data_fault = {
+	.open =		snd_pcm_mmap_data_open,
+	.close =	snd_pcm_mmap_data_close,
+	.fault =	snd_pcm_mmap_data_fault,
+};
+
+/*
+ * mmap the DMA buffer on RAM
+ */
+
+/**
+ * snd_pcm_lib_default_mmap - Default PCM data mmap function
+ * @substream: PCM substream
+ * @area: VMA
+ *
+ * This is the default mmap handler for PCM data.  When mmap pcm_ops is NULL,
+ * this function is invoked implicitly.
+ */
+int snd_pcm_lib_default_mmap(struct snd_pcm_substream *substream,
+			     struct vm_area_struct *area)
+{
+	area->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
+#ifdef CONFIG_GENERIC_ALLOCATOR
+	if (substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV_IRAM) {
+		area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
+		return remap_pfn_range(area, area->vm_start,
+				substream->dma_buffer.addr >> PAGE_SHIFT,
+				area->vm_end - area->vm_start, area->vm_page_prot);
+	}
+#endif /* CONFIG_GENERIC_ALLOCATOR */
+#ifndef CONFIG_X86 /* for avoiding warnings arch/x86/mm/pat.c */
+	if (IS_ENABLED(CONFIG_HAS_DMA) && !substream->ops->page &&
+	    substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV)
+		return dma_mmap_coherent(substream->dma_buffer.dev.dev,
+					 area,
+					 substream->runtime->dma_area,
+					 substream->runtime->dma_addr,
+					 substream->runtime->dma_bytes);
+#endif /* CONFIG_X86 */
+	/* mmap with fault handler */
+	area->vm_ops = &snd_pcm_vm_ops_data_fault;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_pcm_lib_default_mmap);
+
+/*
+ * mmap the DMA buffer on I/O memory area
+ */
+#if SNDRV_PCM_INFO_MMAP_IOMEM
+/**
+ * snd_pcm_lib_mmap_iomem - Default PCM data mmap function for I/O mem
+ * @substream: PCM substream
+ * @area: VMA
+ *
+ * When your hardware uses the iomapped pages as the hardware buffer and
+ * wants to mmap it, pass this function as mmap pcm_ops.  Note that this
+ * is supposed to work only on limited architectures.
+ */
+int snd_pcm_lib_mmap_iomem(struct snd_pcm_substream *substream,
+			   struct vm_area_struct *area)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	area->vm_page_prot = pgprot_noncached(area->vm_page_prot);
+	return vm_iomap_memory(area, runtime->dma_addr, runtime->dma_bytes);
+}
+EXPORT_SYMBOL(snd_pcm_lib_mmap_iomem);
+#endif /* SNDRV_PCM_INFO_MMAP */
+
+/*
+ * mmap DMA buffer
+ */
+int snd_pcm_mmap_data(struct snd_pcm_substream *substream, struct file *file,
+		      struct vm_area_struct *area)
+{
+	struct snd_pcm_runtime *runtime;
+	long size;
+	unsigned long offset;
+	size_t dma_bytes;
+	int err;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		if (!(area->vm_flags & (VM_WRITE|VM_READ)))
+			return -EINVAL;
+	} else {
+		if (!(area->vm_flags & VM_READ))
+			return -EINVAL;
+	}
+	runtime = substream->runtime;
+	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+		return -EBADFD;
+	if (!(runtime->info & SNDRV_PCM_INFO_MMAP))
+		return -ENXIO;
+	if (runtime->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED ||
+	    runtime->access == SNDRV_PCM_ACCESS_RW_NONINTERLEAVED)
+		return -EINVAL;
+	size = area->vm_end - area->vm_start;
+	offset = area->vm_pgoff << PAGE_SHIFT;
+	dma_bytes = PAGE_ALIGN(runtime->dma_bytes);
+	if ((size_t)size > dma_bytes)
+		return -EINVAL;
+	if (offset > dma_bytes - size)
+		return -EINVAL;
+
+	area->vm_ops = &snd_pcm_vm_ops_data;
+	area->vm_private_data = substream;
+	if (substream->ops->mmap)
+		err = substream->ops->mmap(substream, area);
+	else
+		err = snd_pcm_lib_default_mmap(substream, area);
+	if (!err)
+		atomic_inc(&substream->mmap_count);
+	return err;
+}
+EXPORT_SYMBOL(snd_pcm_mmap_data);
+
+static int snd_pcm_mmap(struct file *file, struct vm_area_struct *area)
+{
+	struct snd_pcm_file * pcm_file;
+	struct snd_pcm_substream *substream;	
+	unsigned long offset;
+	
+	pcm_file = file->private_data;
+	substream = pcm_file->substream;
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+
+	offset = area->vm_pgoff << PAGE_SHIFT;
+	switch (offset) {
+	case SNDRV_PCM_MMAP_OFFSET_STATUS:
+		if (!pcm_status_mmap_allowed(pcm_file))
+			return -ENXIO;
+		return snd_pcm_mmap_status(substream, file, area);
+	case SNDRV_PCM_MMAP_OFFSET_CONTROL:
+		if (!pcm_control_mmap_allowed(pcm_file))
+			return -ENXIO;
+		return snd_pcm_mmap_control(substream, file, area);
+	default:
+		return snd_pcm_mmap_data(substream, file, area);
+	}
+	return 0;
+}
+
+static int snd_pcm_fasync(int fd, struct file * file, int on)
+{
+	struct snd_pcm_file * pcm_file;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+
+	pcm_file = file->private_data;
+	substream = pcm_file->substream;
+	if (PCM_RUNTIME_CHECK(substream))
+		return -ENXIO;
+	runtime = substream->runtime;
+	return fasync_helper(fd, file, on, &runtime->fasync);
+}
+
+/*
+ * ioctl32 compat
+ */
+#ifdef CONFIG_COMPAT
+#include "pcm_compat.c"
+#else
+#define snd_pcm_ioctl_compat	NULL
+#endif
+
+/*
+ *  To be removed helpers to keep binary compatibility
+ */
+
+#ifdef CONFIG_SND_SUPPORT_OLD_API
+#define __OLD_TO_NEW_MASK(x) ((x&7)|((x&0x07fffff8)<<5))
+#define __NEW_TO_OLD_MASK(x) ((x&7)|((x&0xffffff00)>>5))
+
+static void snd_pcm_hw_convert_from_old_params(struct snd_pcm_hw_params *params,
+					       struct snd_pcm_hw_params_old *oparams)
+{
+	unsigned int i;
+
+	memset(params, 0, sizeof(*params));
+	params->flags = oparams->flags;
+	for (i = 0; i < ARRAY_SIZE(oparams->masks); i++)
+		params->masks[i].bits[0] = oparams->masks[i];
+	memcpy(params->intervals, oparams->intervals, sizeof(oparams->intervals));
+	params->rmask = __OLD_TO_NEW_MASK(oparams->rmask);
+	params->cmask = __OLD_TO_NEW_MASK(oparams->cmask);
+	params->info = oparams->info;
+	params->msbits = oparams->msbits;
+	params->rate_num = oparams->rate_num;
+	params->rate_den = oparams->rate_den;
+	params->fifo_size = oparams->fifo_size;
+}
+
+static void snd_pcm_hw_convert_to_old_params(struct snd_pcm_hw_params_old *oparams,
+					     struct snd_pcm_hw_params *params)
+{
+	unsigned int i;
+
+	memset(oparams, 0, sizeof(*oparams));
+	oparams->flags = params->flags;
+	for (i = 0; i < ARRAY_SIZE(oparams->masks); i++)
+		oparams->masks[i] = params->masks[i].bits[0];
+	memcpy(oparams->intervals, params->intervals, sizeof(oparams->intervals));
+	oparams->rmask = __NEW_TO_OLD_MASK(params->rmask);
+	oparams->cmask = __NEW_TO_OLD_MASK(params->cmask);
+	oparams->info = params->info;
+	oparams->msbits = params->msbits;
+	oparams->rate_num = params->rate_num;
+	oparams->rate_den = params->rate_den;
+	oparams->fifo_size = params->fifo_size;
+}
+
+static int snd_pcm_hw_refine_old_user(struct snd_pcm_substream *substream,
+				      struct snd_pcm_hw_params_old __user * _oparams)
+{
+	struct snd_pcm_hw_params *params;
+	struct snd_pcm_hw_params_old *oparams = NULL;
+	int err;
+
+	params = kmalloc(sizeof(*params), GFP_KERNEL);
+	if (!params)
+		return -ENOMEM;
+
+	oparams = memdup_user(_oparams, sizeof(*oparams));
+	if (IS_ERR(oparams)) {
+		err = PTR_ERR(oparams);
+		goto out;
+	}
+	snd_pcm_hw_convert_from_old_params(params, oparams);
+	err = snd_pcm_hw_refine(substream, params);
+	if (err < 0)
+		goto out_old;
+
+	err = fixup_unreferenced_params(substream, params);
+	if (err < 0)
+		goto out_old;
+
+	snd_pcm_hw_convert_to_old_params(oparams, params);
+	if (copy_to_user(_oparams, oparams, sizeof(*oparams)))
+		err = -EFAULT;
+out_old:
+	kfree(oparams);
+out:
+	kfree(params);
+	return err;
+}
+
+static int snd_pcm_hw_params_old_user(struct snd_pcm_substream *substream,
+				      struct snd_pcm_hw_params_old __user * _oparams)
+{
+	struct snd_pcm_hw_params *params;
+	struct snd_pcm_hw_params_old *oparams = NULL;
+	int err;
+
+	params = kmalloc(sizeof(*params), GFP_KERNEL);
+	if (!params)
+		return -ENOMEM;
+
+	oparams = memdup_user(_oparams, sizeof(*oparams));
+	if (IS_ERR(oparams)) {
+		err = PTR_ERR(oparams);
+		goto out;
+	}
+
+	snd_pcm_hw_convert_from_old_params(params, oparams);
+	err = snd_pcm_hw_params(substream, params);
+	if (err < 0)
+		goto out_old;
+
+	snd_pcm_hw_convert_to_old_params(oparams, params);
+	if (copy_to_user(_oparams, oparams, sizeof(*oparams)))
+		err = -EFAULT;
+out_old:
+	kfree(oparams);
+out:
+	kfree(params);
+	return err;
+}
+#endif /* CONFIG_SND_SUPPORT_OLD_API */
+
+#ifndef CONFIG_MMU
+static unsigned long snd_pcm_get_unmapped_area(struct file *file,
+					       unsigned long addr,
+					       unsigned long len,
+					       unsigned long pgoff,
+					       unsigned long flags)
+{
+	struct snd_pcm_file *pcm_file = file->private_data;
+	struct snd_pcm_substream *substream = pcm_file->substream;
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	unsigned long offset = pgoff << PAGE_SHIFT;
+
+	switch (offset) {
+	case SNDRV_PCM_MMAP_OFFSET_STATUS:
+		return (unsigned long)runtime->status;
+	case SNDRV_PCM_MMAP_OFFSET_CONTROL:
+		return (unsigned long)runtime->control;
+	default:
+		return (unsigned long)runtime->dma_area + offset;
+	}
+}
+#else
+# define snd_pcm_get_unmapped_area NULL
+#endif
+
+/*
+ *  Register section
+ */
+
+const struct file_operations snd_pcm_f_ops[2] = {
+	{
+		.owner =		THIS_MODULE,
+		.write =		snd_pcm_write,
+		.write_iter =		snd_pcm_writev,
+		.open =			snd_pcm_playback_open,
+		.release =		snd_pcm_release,
+		.llseek =		no_llseek,
+		.poll =			snd_pcm_poll,
+		.unlocked_ioctl =	snd_pcm_ioctl,
+		.compat_ioctl = 	snd_pcm_ioctl_compat,
+		.mmap =			snd_pcm_mmap,
+		.fasync =		snd_pcm_fasync,
+		.get_unmapped_area =	snd_pcm_get_unmapped_area,
+	},
+	{
+		.owner =		THIS_MODULE,
+		.read =			snd_pcm_read,
+		.read_iter =		snd_pcm_readv,
+		.open =			snd_pcm_capture_open,
+		.release =		snd_pcm_release,
+		.llseek =		no_llseek,
+		.poll =			snd_pcm_poll,
+		.unlocked_ioctl =	snd_pcm_ioctl,
+		.compat_ioctl = 	snd_pcm_ioctl_compat,
+		.mmap =			snd_pcm_mmap,
+		.fasync =		snd_pcm_fasync,
+		.get_unmapped_area =	snd_pcm_get_unmapped_area,
+	}
+};