text: /*
   *  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 "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
   * spin until it gets the lock.
   */
  static inline void down_write_nonblock(struct rw_semaphore *lock)
  {
  	while (!down_write_trylock(lock))
  		cond_resched();
  }
  
  #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;
  }
  
  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;
  	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:
  		break;
  	default:
  		snd_pcm_stream_unlock_irq(substream);
  		return -EBADFD;
  	}
  	snd_pcm_stream_unlock_irq(substream);
  #if IS_ENABLED(CONFIG_SND_PCM_OSS)
  	if (!substream->oss.oss)
  #endif
  		if (atomic_read(&substream->mmap_count))
  			return -EBADFD;
  
  	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;
  
  	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);
  	return 0;
   _error:
  	/* 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);
  	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;
  	snd_pcm_stream_lock_irq(substream);
  	switch (runtime->status->state) {
  	case SNDRV_PCM_STATE_SETUP:
  	case SNDRV_PCM_STATE_PREPARED:
  		break;
  	default:
  		snd_pcm_stream_unlock_irq(substream);
  		return -EBADFD;
  	}
  	snd_pcm_stream_unlock_irq(substream);
  	if (atomic_read(&substream->mmap_count))
  		return -EBADFD;
  	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);
  	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 do_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 (do_lock && s != substream) {
  			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:
  	if (do_lock) {
  		/* unlock streams */
  		snd_pcm_group_for_each_entry(s1, substream) {
  			if (s1 != substream) {
  				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);
  	if (snd_pcm_stream_linked(substream))
  		res = snd_pcm_action_group(ops, substream, state, 0);
  	else
  		res = snd_pcm_action_single(ops, substream, state);
  	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;
  	if (runtime->status->state == SNDRV_PCM_STATE_SUSPENDED)
  		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;
  			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;
  	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;
  	return 0;
  }
  
  static void snd_pcm_post_reset(struct snd_pcm_substream *substream, int state)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	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);
  }
  
  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;
  	group = kmalloc(sizeof(*group), GFP_KERNEL);
  	if (!group) {
  		res = -ENOMEM;
  		goto _nolock;
  	}
  	down_write_nonblock(&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_nonblock(&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)
  {
  	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,
  	}
  };
  