power: supply: core: Fix parsing of battery chemistry/technology

[linux-2.6-microblaze.git] / sound / core / pcm_native.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Digital Audio (PCM) abstract layer
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 */

#include <linux/compat.h>
#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 <linux/vmalloc.h>
#include <sound/core.h>
#include <sound/control.h>
#include <sound/info.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/timer.h>
#include <sound/minors.h>
#include <linux/uio.h>
#include <linux/delay.h>

#include "pcm_local.h"

#ifdef CONFIG_SND_DEBUG
#define CREATE_TRACE_POINTS
#include "pcm_param_trace.h"
#else
#define trace_hw_mask_param_enabled()           0
#define trace_hw_interval_param_enabled()       0
#define trace_hw_mask_param(substream, type, index, prev, curr)
#define trace_hw_interval_param(substream, type, index, prev, curr)
#endif

/*
 *  Compatibility
 */

struct snd_pcm_hw_params_old {
        unsigned int flags;
        unsigned int masks[SNDRV_PCM_HW_PARAM_SUBFORMAT -
                           SNDRV_PCM_HW_PARAM_ACCESS + 1];
        struct snd_interval intervals[SNDRV_PCM_HW_PARAM_TICK_TIME -
                                        SNDRV_PCM_HW_PARAM_SAMPLE_BITS + 1];
        unsigned int rmask;
        unsigned int cmask;
        unsigned int info;
        unsigned int msbits;
        unsigned int rate_num;
        unsigned int rate_den;
        snd_pcm_uframes_t fifo_size;
        unsigned char reserved[64];
};

#ifdef CONFIG_SND_SUPPORT_OLD_API
#define SNDRV_PCM_IOCTL_HW_REFINE_OLD _IOWR('A', 0x10, struct snd_pcm_hw_params_old)
#define SNDRV_PCM_IOCTL_HW_PARAMS_OLD _IOWR('A', 0x11, struct snd_pcm_hw_params_old)

static int snd_pcm_hw_refine_old_user(struct snd_pcm_substream *substream,
                                      struct snd_pcm_hw_params_old __user * _oparams);
static int snd_pcm_hw_params_old_user(struct snd_pcm_substream *substream,
                                      struct snd_pcm_hw_params_old __user * _oparams);
#endif
static int snd_pcm_open(struct file *file, struct snd_pcm *pcm, int stream);

/*
 *
 */

static DECLARE_RWSEM(snd_pcm_link_rwsem);

void snd_pcm_group_init(struct snd_pcm_group *group)
{
        spin_lock_init(&group->lock);
        mutex_init(&group->mutex);
        INIT_LIST_HEAD(&group->substreams);
        refcount_set(&group->refs, 1);
}

/* define group lock helpers */
#define DEFINE_PCM_GROUP_LOCK(action, mutex_action) \
static void snd_pcm_group_ ## action(struct snd_pcm_group *group, bool nonatomic) \
{ \
        if (nonatomic) \
                mutex_ ## mutex_action(&group->mutex); \
        else \
                spin_ ## action(&group->lock); \
}

DEFINE_PCM_GROUP_LOCK(lock, lock);
DEFINE_PCM_GROUP_LOCK(unlock, unlock);
DEFINE_PCM_GROUP_LOCK(lock_irq, lock);
DEFINE_PCM_GROUP_LOCK(unlock_irq, unlock);

/**
 * 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_group_lock(&substream->self_group, substream->pcm->nonatomic);
}
EXPORT_SYMBOL_GPL(snd_pcm_stream_lock);

/**
 * snd_pcm_stream_unlock - 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_group_unlock(&substream->self_group, substream->pcm->nonatomic);
}
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_group_lock_irq(&substream->self_group,
                               substream->pcm->nonatomic);
}
EXPORT_SYMBOL_GPL(snd_pcm_stream_lock_irq);

static void snd_pcm_stream_lock_nested(struct snd_pcm_substream *substream)
{
        struct snd_pcm_group *group = &substream->self_group;

        if (substream->pcm->nonatomic)
                mutex_lock_nested(&group->mutex, SINGLE_DEPTH_NESTING);
        else
                spin_lock_nested(&group->lock, SINGLE_DEPTH_NESTING);
}

/**
 * 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_group_unlock_irq(&substream->self_group,
                                 substream->pcm->nonatomic);
}
EXPORT_SYMBOL_GPL(snd_pcm_stream_unlock_irq);

unsigned long _snd_pcm_stream_lock_irqsave(struct snd_pcm_substream *substream)
{
        unsigned long flags = 0;
        if (substream->pcm->nonatomic)
                mutex_lock(&substream->self_group.mutex);
        else
                spin_lock_irqsave(&substream->self_group.lock, flags);
        return flags;
}
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)
{
        if (substream->pcm->nonatomic)
                mutex_unlock(&substream->self_group.mutex);
        else
                spin_unlock_irqrestore(&substream->self_group.lock, flags);
}
EXPORT_SYMBOL_GPL(snd_pcm_stream_unlock_irqrestore);

/* Run PCM ioctl ops */
static int snd_pcm_ops_ioctl(struct snd_pcm_substream *substream,
                             unsigned cmd, void *arg)
{
        if (substream->ops->ioctl)
                return substream->ops->ioctl(substream, cmd, arg);
        else
                return snd_pcm_lib_ioctl(substream, cmd, arg);
}

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;
        strscpy(info->id, pcm->id, sizeof(info->id));
        strscpy(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;
        strscpy(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;
}

/* macro for simplified cast */
#define PARAM_MASK_BIT(b)       (1U << (__force int)(b))

static bool hw_support_mmap(struct snd_pcm_substream *substream)
{
        if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_MMAP))
                return false;

        if (substream->ops->mmap ||
            (substream->dma_buffer.dev.type != SNDRV_DMA_TYPE_DEV &&
             substream->dma_buffer.dev.type != SNDRV_DMA_TYPE_DEV_UC))
                return true;

        return dma_can_mmap(substream->dma_buffer.dev.dev);
}

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 & PARAM_MASK_BIT(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 |= PARAM_MASK_BIT(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 & PARAM_MASK_BIT(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 |= PARAM_MASK_BIT(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 & PARAM_MASK_BIT(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 four dependencies
                 * to SNDRV_PCM_HW_PARAM_XXXs for this rule. The fifth
                 * 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 |= PARAM_MASK_BIT(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 = snd_pcm_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 & PARAM_MASK_BIT(SNDRV_PCM_HW_PARAM_SAMPLE_BITS))
                params->msbits = 0;
        if (params->rmask & PARAM_MASK_BIT(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,
                              snd_pcm_state_t 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
}

void snd_pcm_sync_stop(struct snd_pcm_substream *substream, bool sync_irq)
{
        if (substream->runtime && substream->runtime->stop_operating) {
                substream->runtime->stop_operating = false;
                if (substream->ops && substream->ops->sync_stop)
                        substream->ops->sync_stop(substream);
                else if (sync_irq && substream->pcm->card->sync_irq > 0)
                        synchronize_irq(substream->pcm->card->sync_irq);
        }
}

/**
 * snd_pcm_hw_params_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;

        snd_pcm_sync_stop(substream, true);

        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->managed_buffer_alloc) {
                err = snd_pcm_lib_malloc_pages(substream,
                                               params_buffer_bytes(params));
                if (err < 0)
                        goto _error;
                runtime->buffer_changed = err > 0;
        }

        if (substream->ops->hw_params != NULL) {
                err = substream->ops->hw_params(substream, params);
                if (err < 0)
                        goto _error;
        }

        runtime->access = params_access(params);
        runtime->format = params_format(params);
        runtime->subformat = params_subformat(params);
        runtime->channels = params_channels(params);
        runtime->rate = params_rate(params);
        runtime->period_size = params_period_size(params);
        runtime->periods = params_periods(params);
        runtime->buffer_size = params_buffer_size(params);
        runtime->info = params->info;
        runtime->rate_num = params->rate_num;
        runtime->rate_den = params->rate_den;
        runtime->no_period_wakeup =
                        (params->info & SNDRV_PCM_INFO_NO_PERIOD_WAKEUP) &&
                        (params->flags & SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP);

        bits = snd_pcm_format_physical_width(runtime->format);
        runtime->sample_bits = bits;
        bits *= runtime->channels;
        runtime->frame_bits = bits;
        frames = 1;
        while (bits % 8 != 0) {
                bits *= 2;
                frames *= 2;
        }
        runtime->byte_align = bits / 8;
        runtime->min_align = frames;

        /* Default sw params */
        runtime->tstamp_mode = SNDRV_PCM_TSTAMP_NONE;
        runtime->period_step = 1;
        runtime->control->avail_min = runtime->period_size;
        runtime->start_threshold = 1;
        runtime->stop_threshold = runtime->buffer_size;
        runtime->silence_threshold = 0;
        runtime->silence_size = 0;
        runtime->boundary = runtime->buffer_size;
        while (runtime->boundary * 2 <= LONG_MAX - runtime->buffer_size)
                runtime->boundary *= 2;

        /* clear the buffer for avoiding possible kernel info leaks */
        if (runtime->dma_area && !substream->ops->copy_user) {
                size_t size = runtime->dma_bytes;

                if (runtime->info & SNDRV_PCM_INFO_MMAP)
                        size = PAGE_ALIGN(size);
                memset(runtime->dma_area, 0, size);
        }

        snd_pcm_timer_resolution_change(substream);
        snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP);

        if (cpu_latency_qos_request_active(&substream->latency_pm_qos_req))
                cpu_latency_qos_remove_request(&substream->latency_pm_qos_req);
        usecs = period_to_usecs(runtime);
        if (usecs >= 0)
                cpu_latency_qos_add_request(&substream->latency_pm_qos_req,
                                            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);
        if (substream->managed_buffer_alloc)
                snd_pcm_lib_free_pages(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 do_hw_free(struct snd_pcm_substream *substream)
{
        int result = 0;

        snd_pcm_sync_stop(substream, true);
        if (substream->ops->hw_free)
                result = substream->ops->hw_free(substream);
        if (substream->managed_buffer_alloc)
                snd_pcm_lib_free_pages(substream);
        return result;
}

static int snd_pcm_hw_free(struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime;
        int result;

        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;
        result = do_hw_free(substream);
        snd_pcm_set_state(substream, SNDRV_PCM_STATE_OPEN);
        cpu_latency_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_status64(struct snd_pcm_substream *substream,
                     struct snd_pcm_status64 *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_sec = runtime->trigger_tstamp.tv_sec;
        status->trigger_tstamp_nsec = runtime->trigger_tstamp.tv_nsec;
        if (snd_pcm_running(substream)) {
                snd_pcm_update_hw_ptr(substream);
                if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) {
                        status->tstamp_sec = runtime->status->tstamp.tv_sec;
                        status->tstamp_nsec =
                                runtime->status->tstamp.tv_nsec;
                        status->driver_tstamp_sec =
                                runtime->driver_tstamp.tv_sec;
                        status->driver_tstamp_nsec =
                                runtime->driver_tstamp.tv_nsec;
                        status->audio_tstamp_sec =
                                runtime->status->audio_tstamp.tv_sec;
                        status->audio_tstamp_nsec =
                                runtime->status->audio_tstamp.tv_nsec;
                        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) {
                        struct timespec64 tstamp;

                        snd_pcm_gettime(runtime, &tstamp);
                        status->tstamp_sec = tstamp.tv_sec;
                        status->tstamp_nsec = tstamp.tv_nsec;
                }
        }
 _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_user64(struct snd_pcm_substream *substream,
                                 struct snd_pcm_status64 __user * _status,
                                 bool ext)
{
        struct snd_pcm_status64 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_status64(substream, &status);
        if (res < 0)
                return res;
        if (copy_to_user(_status, &status, sizeof(status)))
                return -EFAULT;
        return 0;
}

static int snd_pcm_status_user32(struct snd_pcm_substream *substream,
                                 struct snd_pcm_status32 __user * _status,
                                 bool ext)
{
        struct snd_pcm_status64 status64;
        struct snd_pcm_status32 status32;
        int res;

        memset(&status64, 0, sizeof(status64));
        memset(&status32, 0, sizeof(status32));
        /*
         * with extension, parameters are read/write,
         * get audio_tstamp_data from user,
         * ignore rest of status structure
         */
        if (ext && get_user(status64.audio_tstamp_data,
                            (u32 __user *)(&_status->audio_tstamp_data)))
                return -EFAULT;
        res = snd_pcm_status64(substream, &status64);
        if (res < 0)
                return res;

        status32 = (struct snd_pcm_status32) {
                .state = status64.state,
                .trigger_tstamp_sec = status64.trigger_tstamp_sec,
                .trigger_tstamp_nsec = status64.trigger_tstamp_nsec,
                .tstamp_sec = status64.tstamp_sec,
                .tstamp_nsec = status64.tstamp_nsec,
                .appl_ptr = status64.appl_ptr,
                .hw_ptr = status64.hw_ptr,
                .delay = status64.delay,
                .avail = status64.avail,
                .avail_max = status64.avail_max,
                .overrange = status64.overrange,
                .suspended_state = status64.suspended_state,
                .audio_tstamp_data = status64.audio_tstamp_data,
                .audio_tstamp_sec = status64.audio_tstamp_sec,
                .audio_tstamp_nsec = status64.audio_tstamp_nsec,
                .driver_tstamp_sec = status64.audio_tstamp_sec,
                .driver_tstamp_nsec = status64.audio_tstamp_nsec,
                .audio_tstamp_accuracy = status64.audio_tstamp_accuracy,
        };

        if (copy_to_user(_status, &status32, sizeof(status32)))
                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 snd_pcm_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;
}

#define ACTION_ARG_IGNORE       (__force snd_pcm_state_t)0

struct action_ops {
        int (*pre_action)(struct snd_pcm_substream *substream,
                          snd_pcm_state_t state);
        int (*do_action)(struct snd_pcm_substream *substream,
                         snd_pcm_state_t state);
        void (*undo_action)(struct snd_pcm_substream *substream,
                            snd_pcm_state_t state);
        void (*post_action)(struct snd_pcm_substream *substream,
                            snd_pcm_state_t 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,
                                snd_pcm_state_t state,
                                bool 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,
                                 snd_pcm_state_t 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;
}

static void snd_pcm_group_assign(struct snd_pcm_substream *substream,
                                 struct snd_pcm_group *new_group)
{
        substream->group = new_group;
        list_move(&substream->link_list, &new_group->substreams);
}

/*
 * Unref and unlock the group, but keep the stream lock;
 * when the group becomes empty and no longer referred, destroy itself
 */
static void snd_pcm_group_unref(struct snd_pcm_group *group,
                                struct snd_pcm_substream *substream)
{
        bool do_free;

        if (!group)
                return;
        do_free = refcount_dec_and_test(&group->refs);
        snd_pcm_group_unlock(group, substream->pcm->nonatomic);
        if (do_free)
                kfree(group);
}

/*
 * Lock the group inside a stream lock and reference it;
 * return the locked group object, or NULL if not linked
 */
static struct snd_pcm_group *
snd_pcm_stream_group_ref(struct snd_pcm_substream *substream)
{
        bool nonatomic = substream->pcm->nonatomic;
        struct snd_pcm_group *group;
        bool trylock;

        for (;;) {
                if (!snd_pcm_stream_linked(substream))
                        return NULL;
                group = substream->group;
                /* block freeing the group object */
                refcount_inc(&group->refs);

                trylock = nonatomic ? mutex_trylock(&group->mutex) :
                        spin_trylock(&group->lock);
                if (trylock)
                        break; /* OK */

                /* re-lock for avoiding ABBA deadlock */
                snd_pcm_stream_unlock(substream);
                snd_pcm_group_lock(group, nonatomic);
                snd_pcm_stream_lock(substream);

                /* check the group again; the above opens a small race window */
                if (substream->group == group)
                        break; /* OK */
                /* group changed, try again */
                snd_pcm_group_unref(group, substream);
        }
        return group;
}

/*
 *  Note: call with stream lock
 */
static int snd_pcm_action(const struct action_ops *ops,
                          struct snd_pcm_substream *substream,
                          snd_pcm_state_t state)
{
        struct snd_pcm_group *group;
        int res;

        group = snd_pcm_stream_group_ref(substream);
        if (group)
                res = snd_pcm_action_group(ops, substream, state, true);
        else
                res = snd_pcm_action_single(ops, substream, state);
        snd_pcm_group_unref(group, substream);
        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,
                                   snd_pcm_state_t 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,
                                    snd_pcm_state_t state)
{
        int res;

        /* Guarantee the group members won't change during non-atomic action */
        down_read(&snd_pcm_link_rwsem);
        if (snd_pcm_stream_linked(substream))
                res = snd_pcm_action_group(ops, substream, state, false);
        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,
                             snd_pcm_state_t 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,
                            snd_pcm_state_t 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,
                               snd_pcm_state_t 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,
                               snd_pcm_state_t 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,
                            snd_pcm_state_t 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,
                           snd_pcm_state_t state)
{
        if (substream->runtime->trigger_master == substream &&
            snd_pcm_running(substream)) {
                substream->ops->trigger(substream, SNDRV_PCM_TRIGGER_STOP);
                substream->runtime->stop_operating = true;
        }
        return 0; /* unconditionally stop all substreams */
}

static void snd_pcm_post_stop(struct snd_pcm_substream *substream,
                              snd_pcm_state_t 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 successful, 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: pass boolean (to start pause or resume) as state argument
 */
#define pause_pushed(state)     (__force bool)(state)

static int snd_pcm_pre_pause(struct snd_pcm_substream *substream,
                             snd_pcm_state_t state)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        if (!(runtime->info & SNDRV_PCM_INFO_PAUSE))
                return -ENOSYS;
        if (pause_pushed(state)) {
                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,
                            snd_pcm_state_t state)
{
        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 (pause_pushed(state))
                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,
                                       pause_pushed(state) ?
                                       SNDRV_PCM_TRIGGER_PAUSE_PUSH :
                                       SNDRV_PCM_TRIGGER_PAUSE_RELEASE);
}

static void snd_pcm_undo_pause(struct snd_pcm_substream *substream,
                               snd_pcm_state_t state)
{
        if (substream->runtime->trigger_master == substream)
                substream->ops->trigger(substream,
                                        pause_pushed(state) ?
                                        SNDRV_PCM_TRIGGER_PAUSE_RELEASE :
                                        SNDRV_PCM_TRIGGER_PAUSE_PUSH);
}

static void snd_pcm_post_pause(struct snd_pcm_substream *substream,
                               snd_pcm_state_t state)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        snd_pcm_trigger_tstamp(substream);
        if (pause_pushed(state)) {
                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, bool push)
{
        return snd_pcm_action(&snd_pcm_action_pause, substream,
                              (__force snd_pcm_state_t)push);
}

static int snd_pcm_pause_lock_irq(struct snd_pcm_substream *substream,
                                  bool push)
{
        return snd_pcm_action_lock_irq(&snd_pcm_action_pause, substream,
                                       (__force snd_pcm_state_t)push);
}

#ifdef CONFIG_PM
/* suspend callback: state argument ignored */

static int snd_pcm_pre_suspend(struct snd_pcm_substream *substream,
                               snd_pcm_state_t state)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        switch (runtime->status->state) {
        case SNDRV_PCM_STATE_SUSPENDED:
                return -EBUSY;
        /* unresumable PCM state; return -EBUSY for skipping suspend */
        case SNDRV_PCM_STATE_OPEN:
        case SNDRV_PCM_STATE_SETUP:
        case SNDRV_PCM_STATE_DISCONNECTED:
                return -EBUSY;
        }
        runtime->trigger_master = substream;
        return 0;
}

static int snd_pcm_do_suspend(struct snd_pcm_substream *substream,
                              snd_pcm_state_t 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);
        runtime->stop_operating = true;
        return 0; /* suspend unconditionally */
}

static void snd_pcm_post_suspend(struct snd_pcm_substream *substream,
                                 snd_pcm_state_t 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 a negative error code.
 */
static int snd_pcm_suspend(struct snd_pcm_substream *substream)
{
        int err;
        unsigned long flags;

        snd_pcm_stream_lock_irqsave(substream, flags);
        err = snd_pcm_action(&snd_pcm_action_suspend, substream,
                             ACTION_ARG_IGNORE);
        snd_pcm_stream_unlock_irqrestore(substream, flags);
        return err;
}

/**
 * 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_each_pcm_substream(pcm, stream, substream) {
                /* FIXME: the open/close code should lock this as well */
                if (!substream->runtime)
                        continue;

                /*
                 * Skip BE dai link PCM's that are internal and may
                 * not have their substream ops set.
                 */
                if (!substream->ops)
                        continue;

                err = snd_pcm_suspend(substream);
                if (err < 0 && err != -EBUSY)
                        return err;
        }

        for_each_pcm_substream(pcm, stream, substream)
                snd_pcm_sync_stop(substream, false);

        return 0;
}
EXPORT_SYMBOL(snd_pcm_suspend_all);

/* resume callbacks: state argument ignored */

static int snd_pcm_pre_resume(struct snd_pcm_substream *substream,
                              snd_pcm_state_t 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,
                             snd_pcm_state_t 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,
                                snd_pcm_state_t 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,
                                snd_pcm_state_t 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,
                                       ACTION_ARG_IGNORE);
}

#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
 */
/* reset callbacks:  state argument ignored */
static int snd_pcm_pre_reset(struct snd_pcm_substream *substream,
                             snd_pcm_state_t 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,
                            snd_pcm_state_t state)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        int err = snd_pcm_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,
                               snd_pcm_state_t 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,
                                        ACTION_ARG_IGNORE);
}

/*
 * prepare ioctl
 */
/* pass f_flags as state argument */
static int snd_pcm_pre_prepare(struct snd_pcm_substream *substream,
                               snd_pcm_state_t state)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        int f_flags = (__force int)state;

        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,
                              snd_pcm_state_t state)
{
        int err;
        snd_pcm_sync_stop(substream, true);
        err = substream->ops->prepare(substream);
        if (err < 0)
                return err;
        return snd_pcm_do_reset(substream, state);
}

static void snd_pcm_post_prepare(struct snd_pcm_substream *substream,
                                 snd_pcm_state_t 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, false);
                fallthrough;
        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,
                                        (__force snd_pcm_state_t)f_flags);
}

/*
 * drain ioctl
 */

/* drain init callbacks: state argument ignored */
static int snd_pcm_pre_drain_init(struct snd_pcm_substream *substream,
                                  snd_pcm_state_t 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,
                                 snd_pcm_state_t 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) {
                        snd_pcm_state_t new_state;

                        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,
                                    snd_pcm_state_t 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
};

/*
 * 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;
        struct snd_pcm_group *group;
        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;

        snd_pcm_stream_lock_irq(substream);
        /* resume pause */
        if (runtime->status->state == SNDRV_PCM_STATE_PAUSED)
                snd_pcm_pause(substream, false);

        /* pre-start/stop - all running streams are changed to DRAINING state */
        result = snd_pcm_action(&snd_pcm_action_drain_init, substream,
                                ACTION_ARG_IGNORE);
        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;
                group = snd_pcm_stream_group_ref(substream);
                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;
                        }
                }
                snd_pcm_group_unref(group, substream);
                if (!to_check)
                        break; /* all drained */
                init_waitqueue_entry(&wait, current);
                set_current_state(TASK_INTERRUPTIBLE);
                add_wait_queue(&to_check->sleep, &wait);
                snd_pcm_stream_unlock_irq(substream);
                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(tout);

                snd_pcm_stream_lock_irq(substream);
                group = snd_pcm_stream_group_ref(substream);
                snd_pcm_group_for_each_entry(s, substream) {
                        if (s->runtime == to_check) {
                                remove_wait_queue(&to_check->sleep, &wait);
                                break;
                        }
                }
                snd_pcm_group_unref(group, substream);

                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);

        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, false);

        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);
        struct snd_pcm *pcm;
        unsigned int minor;

        if (!S_ISCHR(inode->i_mode) || imajor(inode) != snd_major)
                return false;
        minor = iminor(inode);
        pcm = snd_lookup_minor_data(minor, SNDRV_DEVICE_TYPE_PCM_PLAYBACK);
        if (!pcm)
                pcm = snd_lookup_minor_data(minor, SNDRV_DEVICE_TYPE_PCM_CAPTURE);
        if (!pcm)
                return false;
        snd_card_unref(pcm->card);
        return true;
}

/*
 * 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, *target_group;
        bool nonatomic = substream->pcm->nonatomic;
        struct fd f = fdget(fd);

        if (!f.file)
                return -EBADFD;
        if (!is_pcm_file(f.file)) {
                res = -EBADFD;
                goto _badf;
        }
        pcm_file = f.file->private_data;
        substream1 = pcm_file->substream;

        if (substream == substream1) {
                res = -EINVAL;
                goto _badf;
        }

        group = kzalloc(sizeof(*group), GFP_KERNEL);
        if (!group) {
                res = -ENOMEM;
                goto _nolock;
        }
        snd_pcm_group_init(group);

        down_write(&snd_pcm_link_rwsem);
        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;
        }

        snd_pcm_stream_lock_irq(substream);
        if (!snd_pcm_stream_linked(substream)) {
                snd_pcm_group_assign(substream, group);
                group = NULL; /* assigned, don't free this one below */
        }
        target_group = substream->group;
        snd_pcm_stream_unlock_irq(substream);

        snd_pcm_group_lock_irq(target_group, nonatomic);
        snd_pcm_stream_lock_nested(substream1);
        snd_pcm_group_assign(substream1, target_group);
        refcount_inc(&target_group->refs);
        snd_pcm_stream_unlock(substream1);
        snd_pcm_group_unlock_irq(target_group, nonatomic);
 _end:
        up_write(&snd_pcm_link_rwsem);
 _nolock:
        kfree(group);
 _badf:
        fdput(f);
        return res;
}

static void relink_to_local(struct snd_pcm_substream *substream)
{
        snd_pcm_stream_lock_nested(substream);
        snd_pcm_group_assign(substream, &substream->self_group);
        snd_pcm_stream_unlock(substream);
}

static int snd_pcm_unlink(struct snd_pcm_substream *substream)
{
        struct snd_pcm_group *group;
        bool nonatomic = substream->pcm->nonatomic;
        bool do_free = false;
        int res = 0;

        down_write(&snd_pcm_link_rwsem);

        if (!snd_pcm_stream_linked(substream)) {
                res = -EALREADY;
                goto _end;
        }

        group = substream->group;
        snd_pcm_group_lock_irq(group, nonatomic);

        relink_to_local(substream);
        refcount_dec(&group->refs);

        /* detach the last stream, too */
        if (list_is_singular(&group->substreams)) {
                relink_to_local(list_first_entry(&group->substreams,
                                                 struct snd_pcm_substream,
                                                 link_list));
                do_free = refcount_dec_and_test(&group->refs);
        }

        snd_pcm_group_unlock_irq(group, nonatomic);
        if (do_free)
                kfree(group);

       _end:
        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)
{
        snd_pcm_format_t 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);
        pcm_for_each_format(k) {
                int bits;
                if (!snd_mask_test_format(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, (__force unsigned)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;
        snd_pcm_format_t k;

        t.min = UINT_MAX;
        t.max = 0;
        t.openmin = 0;
        t.openmax = 0;
        pcm_for_each_format(k) {
                int bits;
                if (!snd_mask_test_format(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, 352800, 384000
};

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);
}               

static 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;
}

static 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 |= PARAM_MASK_BIT(SNDRV_PCM_ACCESS_RW_INTERLEAVED);
        if (hw->info & SNDRV_PCM_INFO_NONINTERLEAVED)
                mask |= PARAM_MASK_BIT(SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
        if (hw_support_mmap(substream)) {
                if (hw->info & SNDRV_PCM_INFO_INTERLEAVED)
                        mask |= PARAM_MASK_BIT(SNDRV_PCM_ACCESS_MMAP_INTERLEAVED);
                if (hw->info & SNDRV_PCM_INFO_NONINTERLEAVED)
                        mask |= PARAM_MASK_BIT(SNDRV_PCM_ACCESS_MMAP_NONINTERLEAVED);
                if (hw->info & SNDRV_PCM_INFO_COMPLEX)
                        mask |= PARAM_MASK_BIT(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,
                                         PARAM_MASK_BIT(SNDRV_PCM_SUBFORMAT_STD));
        if (err < 0)
                return err;

        err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_CHANNELS,
                                           hw->channels_min, hw->channels_max);
        if (err < 0)
                return err;

        err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_RATE,
                                           hw->rate_min, hw->rate_max);
        if (err < 0)
                return err;

        err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
                                           hw->period_bytes_min, hw->period_bytes_max);
        if (err < 0)
                return err;

        err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIODS,
                                           hw->periods_min, hw->periods_max);
        if (err < 0)
                return err;

        err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
                                           hw->period_bytes_min, hw->buffer_bytes_max);
        if (err < 0)
                return err;

        err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 
                                  snd_pcm_hw_rule_buffer_bytes_max, substream,
                                  SNDRV_PCM_HW_PARAM_BUFFER_BYTES, -1);
        if (err < 0)
                return err;

        /* FIXME: remove */
        if (runtime->dma_bytes) {
                err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 0, runtime->dma_bytes);
                if (err < 0)
                        return err;
        }

        if (!(hw->rates & (SNDRV_PCM_RATE_KNOT | SNDRV_PCM_RATE_CONTINUOUS))) {
                err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE, 
                                          snd_pcm_hw_rule_rate, hw,
                                          SNDRV_PCM_HW_PARAM_RATE, -1);
                if (err < 0)
                        return err;
        }

        /* FIXME: this belong to lowlevel */
        snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);

        return 0;
}

static void pcm_release_private(struct snd_pcm_substream *substream)
{
        if (snd_pcm_stream_linked(substream))
                snd_pcm_unlink(substream);
}

void snd_pcm_release_substream(struct snd_pcm_substream *substream)
{
        substream->ref_count--;
        if (substream->ref_count > 0)
                return;

        snd_pcm_drop(substream);
        if (substream->hw_opened) {
                if (substream->runtime->status->state != SNDRV_PCM_STATE_OPEN)
                        do_hw_free(substream);
                substream->ops->close(substream);
                substream->hw_opened = 0;
        }
        if (cpu_latency_qos_request_active(&substream->latency_pm_qos_req))
                cpu_latency_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;
        }

        err = substream->ops->open(substream);
        if (err < 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->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;

        /* block until the device gets woken up as it may touch the hardware */
        snd_power_wait(pcm->card);

        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;
                fallthrough;
        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;
}

struct snd_pcm_mmap_status32 {
        snd_pcm_state_t state;
        s32 pad1;
        u32 hw_ptr;
        s32 tstamp_sec;
        s32 tstamp_nsec;
        snd_pcm_state_t suspended_state;
        s32 audio_tstamp_sec;
        s32 audio_tstamp_nsec;
} __attribute__((packed));

struct snd_pcm_mmap_control32 {
        u32 appl_ptr;
        u32 avail_min;
};

struct snd_pcm_sync_ptr32 {
        u32 flags;
        union {
                struct snd_pcm_mmap_status32 status;
                unsigned char reserved[64];
        } s;
        union {
                struct snd_pcm_mmap_control32 control;
                unsigned char reserved[64];
        } c;
} __attribute__((packed));

/* recalcuate the boundary within 32bit */
static snd_pcm_uframes_t recalculate_boundary(struct snd_pcm_runtime *runtime)
{
        snd_pcm_uframes_t boundary;

        if (! runtime->buffer_size)
                return 0;
        boundary = runtime->buffer_size;
        while (boundary * 2 <= 0x7fffffffUL - runtime->buffer_size)
                boundary *= 2;
        return boundary;
}

static int snd_pcm_ioctl_sync_ptr_compat(struct snd_pcm_substream *substream,
                                         struct snd_pcm_sync_ptr32 __user *src)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        volatile struct snd_pcm_mmap_status *status;
        volatile struct snd_pcm_mmap_control *control;
        u32 sflags;
        struct snd_pcm_mmap_control scontrol;
        struct snd_pcm_mmap_status sstatus;
        snd_pcm_uframes_t boundary;
        int err;

        if (snd_BUG_ON(!runtime))
                return -EINVAL;

        if (get_user(sflags, &src->flags) ||
            get_user(scontrol.appl_ptr, &src->c.control.appl_ptr) ||
            get_user(scontrol.avail_min, &src->c.control.avail_min))
                return -EFAULT;
        if (sflags & SNDRV_PCM_SYNC_PTR_HWSYNC) {
                err = snd_pcm_hwsync(substream);
                if (err < 0)
                        return err;
        }
        status = runtime->status;
        control = runtime->control;
        boundary = recalculate_boundary(runtime);
        if (! boundary)
                boundary = 0x7fffffff;
        snd_pcm_stream_lock_irq(substream);
        /* FIXME: we should consider the boundary for the sync from app */
        if (!(sflags & SNDRV_PCM_SYNC_PTR_APPL))
                control->appl_ptr = scontrol.appl_ptr;
        else
                scontrol.appl_ptr = control->appl_ptr % boundary;
        if (!(sflags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
                control->avail_min = scontrol.avail_min;
        else
                scontrol.avail_min = control->avail_min;
        sstatus.state = status->state;
        sstatus.hw_ptr = status->hw_ptr % boundary;
        sstatus.tstamp = status->tstamp;
        sstatus.suspended_state = status->suspended_state;
        sstatus.audio_tstamp = status->audio_tstamp;
        snd_pcm_stream_unlock_irq(substream);
        if (put_user(sstatus.state, &src->s.status.state) ||
            put_user(sstatus.hw_ptr, &src->s.status.hw_ptr) ||
            put_user(sstatus.tstamp.tv_sec, &src->s.status.tstamp_sec) ||
            put_user(sstatus.tstamp.tv_nsec, &src->s.status.tstamp_nsec) ||
            put_user(sstatus.suspended_state, &src->s.status.suspended_state) ||
            put_user(sstatus.audio_tstamp.tv_sec, &src->s.status.audio_tstamp_sec) ||
            put_user(sstatus.audio_tstamp.tv_nsec, &src->s.status.audio_tstamp_nsec) ||
            put_user(scontrol.appl_ptr, &src->c.control.appl_ptr) ||
            put_user(scontrol.avail_min, &src->c.control.avail_min))
                return -EFAULT;

        return 0;
}
#define __SNDRV_PCM_IOCTL_SYNC_PTR32 _IOWR('A', 0x23, struct snd_pcm_sync_ptr32)

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);
        if (put_user(result, &_xferi->result))
                return -EFAULT;
        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);
        if (put_user(result, &_xfern->result))
                return -EFAULT;
        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);
        if (put_user(result, _frames))
                return -EFAULT;
        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);
        if (put_user(result, _frames))
                return -EFAULT;
        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);
        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_STATUS32:
                return snd_pcm_status_user32(substream, arg, false);
        case SNDRV_PCM_IOCTL_STATUS_EXT32:
                return snd_pcm_status_user32(substream, arg, true);
        case SNDRV_PCM_IOCTL_STATUS64:
                return snd_pcm_status_user64(substream, arg, false);
        case SNDRV_PCM_IOCTL_STATUS_EXT64:
                return snd_pcm_status_user64(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_PTR32:
                return snd_pcm_ioctl_sync_ptr_compat(substream, arg);
        case __SNDRV_PCM_IOCTL_SYNC_PTR64:
                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_pause_lock_irq(substream, (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)
{
        /* 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 */

/*
 * 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_sgbuf_get_page(snd_pcm_get_dma_buf(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;
        if (!substream->ops->page &&
            !snd_dma_buffer_mmap(snd_pcm_get_dma_buf(substream), area))
                return 0;
        /* 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_OLD:
                if (pcm_file->no_compat_mmap || !IS_ENABLED(CONFIG_64BIT))
                        return -ENXIO;
                fallthrough;
        case SNDRV_PCM_MMAP_OFFSET_STATUS_NEW:
                if (!pcm_status_mmap_allowed(pcm_file))
                        return -ENXIO;
                return snd_pcm_mmap_status(substream, file, area);
        case SNDRV_PCM_MMAP_OFFSET_CONTROL_OLD:
                if (pcm_file->no_compat_mmap || !IS_ENABLED(CONFIG_64BIT))
                        return -ENXIO;
                fallthrough;
        case SNDRV_PCM_MMAP_OFFSET_CONTROL_NEW:
                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_NEW:
                return (unsigned long)runtime->status;
        case SNDRV_PCM_MMAP_OFFSET_CONTROL_NEW:
                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,
        }
};