/*
 *  compress_core.c - compress offload core
 *
 *  Copyright (C) 2011 Intel Corporation
 *  Authors:    Vinod Koul <vinod.koul@linux.intel.com>
 *              Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 */
#define FORMAT(fmt) "%s: %d: " fmt, __func__, __LINE__
#define pr_fmt(fmt) KBUILD_MODNAME ": " FORMAT(fmt)

#include <linux/file.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/math64.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/uio.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/compat.h>
#include <sound/core.h>
#include <sound/initval.h>
#include <sound/info.h>
#include <sound/compress_params.h>
#include <sound/compress_offload.h>
#include <sound/compress_driver.h>

/* struct snd_compr_codec_caps overflows the ioctl bit size for some
 * architectures, so we need to disable the relevant ioctls.
 */
#if _IOC_SIZEBITS < 14
#define COMPR_CODEC_CAPS_OVERFLOW
#endif

/* TODO:
 * - add substream support for multiple devices in case of
 *      SND_DYNAMIC_MINORS is not used
 * - Multiple node representation
 *      driver should be able to register multiple nodes
 */

static DEFINE_MUTEX(device_mutex);

struct snd_compr_file {
        unsigned long caps;
        struct snd_compr_stream stream;
};

static void error_delayed_work(struct work_struct *work);

/*
 * a note on stream states used:
 * we use following states in the compressed core
 * SNDRV_PCM_STATE_OPEN: When stream has been opened.
 * SNDRV_PCM_STATE_SETUP: When stream has been initialized. This is done by
 *      calling SNDRV_COMPRESS_SET_PARAMS. Running streams will come to this
 *      state at stop by calling SNDRV_COMPRESS_STOP, or at end of drain.
 * SNDRV_PCM_STATE_PREPARED: When a stream has been written to (for
 *      playback only). User after setting up stream writes the data buffer
 *      before starting the stream.
 * SNDRV_PCM_STATE_RUNNING: When stream has been started and is
 *      decoding/encoding and rendering/capturing data.
 * SNDRV_PCM_STATE_DRAINING: When stream is draining current data. This is done
 *      by calling SNDRV_COMPRESS_DRAIN.
 * SNDRV_PCM_STATE_PAUSED: When stream is paused. This is done by calling
 *      SNDRV_COMPRESS_PAUSE. It can be stopped or resumed by calling
 *      SNDRV_COMPRESS_STOP or SNDRV_COMPRESS_RESUME respectively.
 */
static int snd_compr_open(struct inode *inode, struct file *f)
{
        struct snd_compr *compr;
        struct snd_compr_file *data;
        struct snd_compr_runtime *runtime;
        enum snd_compr_direction dirn;
        int maj = imajor(inode);
        int ret;

        if ((f->f_flags & O_ACCMODE) == O_WRONLY)
                dirn = SND_COMPRESS_PLAYBACK;
        else if ((f->f_flags & O_ACCMODE) == O_RDONLY)
                dirn = SND_COMPRESS_CAPTURE;
        else
                return -EINVAL;

        if (maj == snd_major)
                compr = snd_lookup_minor_data(iminor(inode),
                                        SNDRV_DEVICE_TYPE_COMPRESS);
        else
                return -EBADFD;

        if (compr == NULL) {
                pr_err("no device data!!!\n");
                return -ENODEV;
        }

        if (dirn != compr->direction) {
                pr_err("this device doesn't support this direction\n");
                snd_card_unref(compr->card);
                return -EINVAL;
        }

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (!data) {
                snd_card_unref(compr->card);
                return -ENOMEM;
        }

        INIT_DELAYED_WORK(&data->stream.error_work, error_delayed_work);

        data->stream.ops = compr->ops;
        data->stream.direction = dirn;
        data->stream.private_data = compr->private_data;
        data->stream.device = compr;
        runtime = kzalloc(sizeof(*runtime), GFP_KERNEL);
        if (!runtime) {
                kfree(data);
                snd_card_unref(compr->card);
                return -ENOMEM;
        }
        runtime->state = SNDRV_PCM_STATE_OPEN;
        init_waitqueue_head(&runtime->sleep);
        data->stream.runtime = runtime;
        f->private_data = (void *)data;
        mutex_lock(&compr->lock);
        ret = compr->ops->open(&data->stream);
        mutex_unlock(&compr->lock);
        if (ret) {
                kfree(runtime);
                kfree(data);
        }
        snd_card_unref(compr->card);
        return ret;
}

static int snd_compr_free(struct inode *inode, struct file *f)
{
        struct snd_compr_file *data = f->private_data;
        struct snd_compr_runtime *runtime = data->stream.runtime;

        cancel_delayed_work_sync(&data->stream.error_work);

        switch (runtime->state) {
        case SNDRV_PCM_STATE_RUNNING:
        case SNDRV_PCM_STATE_DRAINING:
        case SNDRV_PCM_STATE_PAUSED:
                data->stream.ops->trigger(&data->stream, SNDRV_PCM_TRIGGER_STOP);
                break;
        default:
                break;
        }

        data->stream.ops->free(&data->stream);
        if (!data->stream.runtime->dma_buffer_p)
                kfree(data->stream.runtime->buffer);
        kfree(data->stream.runtime);
        kfree(data);
        return 0;
}

static int snd_compr_update_tstamp(struct snd_compr_stream *stream,
                struct snd_compr_tstamp *tstamp)
{
        if (!stream->ops->pointer)
                return -ENOTSUPP;
        stream->ops->pointer(stream, tstamp);
        pr_debug("dsp consumed till %d total %d bytes\n",
                tstamp->byte_offset, tstamp->copied_total);
        if (stream->direction == SND_COMPRESS_PLAYBACK)
                stream->runtime->total_bytes_transferred = tstamp->copied_total;
        else
                stream->runtime->total_bytes_available = tstamp->copied_total;
        return 0;
}

static size_t snd_compr_calc_avail(struct snd_compr_stream *stream,
                struct snd_compr_avail *avail)
{
        memset(avail, 0, sizeof(*avail));
        snd_compr_update_tstamp(stream, &avail->tstamp);
        /* Still need to return avail even if tstamp can't be filled in */

        if (stream->runtime->total_bytes_available == 0 &&
                        stream->runtime->state == SNDRV_PCM_STATE_SETUP &&
                        stream->direction == SND_COMPRESS_PLAYBACK) {
                pr_debug("detected init and someone forgot to do a write\n");
                return stream->runtime->buffer_size;
        }
        pr_debug("app wrote %lld, DSP consumed %lld\n",
                        stream->runtime->total_bytes_available,
                        stream->runtime->total_bytes_transferred);
        if (stream->runtime->total_bytes_available ==
                                stream->runtime->total_bytes_transferred) {
                if (stream->direction == SND_COMPRESS_PLAYBACK) {
                        pr_debug("both pointers are same, returning full avail\n");
                        return stream->runtime->buffer_size;
                } else {
                        pr_debug("both pointers are same, returning no avail\n");
                        return 0;
                }
        }

        avail->avail = stream->runtime->total_bytes_available -
                        stream->runtime->total_bytes_transferred;
        if (stream->direction == SND_COMPRESS_PLAYBACK)
                avail->avail = stream->runtime->buffer_size - avail->avail;

        pr_debug("ret avail as %lld\n", avail->avail);
        return avail->avail;
}

static inline size_t snd_compr_get_avail(struct snd_compr_stream *stream)
{
        struct snd_compr_avail avail;

        return snd_compr_calc_avail(stream, &avail);
}

static int
snd_compr_ioctl_avail(struct snd_compr_stream *stream, unsigned long arg)
{
        struct snd_compr_avail ioctl_avail;
        size_t avail;

        avail = snd_compr_calc_avail(stream, &ioctl_avail);
        ioctl_avail.avail = avail;

        switch (stream->runtime->state) {
        case SNDRV_PCM_STATE_OPEN:
                return -EBADFD;
        case SNDRV_PCM_STATE_XRUN:
                return -EPIPE;
        default:
                break;
        }

        if (copy_to_user((__u64 __user *)arg,
                                &ioctl_avail, sizeof(ioctl_avail)))
                return -EFAULT;
        return 0;
}

static int snd_compr_write_data(struct snd_compr_stream *stream,
               const char __user *buf, size_t count)
{
        void *dstn;
        size_t copy;
        struct snd_compr_runtime *runtime = stream->runtime;
        /* 64-bit Modulus */
        u64 app_pointer = div64_u64(runtime->total_bytes_available,
                                    runtime->buffer_size);
        app_pointer = runtime->total_bytes_available -
                      (app_pointer * runtime->buffer_size);

        dstn = runtime->buffer + app_pointer;
        pr_debug("copying %ld at %lld\n",
                        (unsigned long)count, app_pointer);
        if (count < runtime->buffer_size - app_pointer) {
                if (copy_from_user(dstn, buf, count))
                        return -EFAULT;
        } else {
                copy = runtime->buffer_size - app_pointer;
                if (copy_from_user(dstn, buf, copy))
                        return -EFAULT;
                if (copy_from_user(runtime->buffer, buf + copy, count - copy))
                        return -EFAULT;
        }
        /* if DSP cares, let it know data has been written */
        if (stream->ops->ack)
                stream->ops->ack(stream, count);
        return count;
}

static ssize_t snd_compr_write(struct file *f, const char __user *buf,
                size_t count, loff_t *offset)
{
        struct snd_compr_file *data = f->private_data;
        struct snd_compr_stream *stream;
        size_t avail;
        int retval;

        if (snd_BUG_ON(!data))
                return -EFAULT;

        stream = &data->stream;
        mutex_lock(&stream->device->lock);
        /* write is allowed when stream is running or has been steup */
        switch (stream->runtime->state) {
        case SNDRV_PCM_STATE_SETUP:
        case SNDRV_PCM_STATE_PREPARED:
        case SNDRV_PCM_STATE_RUNNING:
                break;
        default:
                mutex_unlock(&stream->device->lock);
                return -EBADFD;
        }

        avail = snd_compr_get_avail(stream);
        pr_debug("avail returned %ld\n", (unsigned long)avail);
        /* calculate how much we can write to buffer */
        if (avail > count)
                avail = count;

        if (stream->ops->copy) {
                char __user* cbuf = (char __user*)buf;
                retval = stream->ops->copy(stream, cbuf, avail);
        } else {
                retval = snd_compr_write_data(stream, buf, avail);
        }
        if (retval > 0)
                stream->runtime->total_bytes_available += retval;

        /* while initiating the stream, write should be called before START
         * call, so in setup move state */
        if (stream->runtime->state == SNDRV_PCM_STATE_SETUP) {
                stream->runtime->state = SNDRV_PCM_STATE_PREPARED;
                pr_debug("stream prepared, Houston we are good to go\n");
        }

        mutex_unlock(&stream->device->lock);
        return retval;
}


static ssize_t snd_compr_read(struct file *f, char __user *buf,
                size_t count, loff_t *offset)
{
        struct snd_compr_file *data = f->private_data;
        struct snd_compr_stream *stream;
        size_t avail;
        int retval;

        if (snd_BUG_ON(!data))
                return -EFAULT;

        stream = &data->stream;
        mutex_lock(&stream->device->lock);

        /* read is allowed when stream is running, paused, draining and setup
         * (yes setup is state which we transition to after stop, so if user
         * wants to read data after stop we allow that)
         */
        switch (stream->runtime->state) {
        case SNDRV_PCM_STATE_OPEN:
        case SNDRV_PCM_STATE_PREPARED:
        case SNDRV_PCM_STATE_SUSPENDED:
        case SNDRV_PCM_STATE_DISCONNECTED:
                retval = -EBADFD;
                goto out;
        case SNDRV_PCM_STATE_XRUN:
                retval = -EPIPE;
                goto out;
        }

        avail = snd_compr_get_avail(stream);
        pr_debug("avail returned %ld\n", (unsigned long)avail);
        /* calculate how much we can read from buffer */
        if (avail > count)
                avail = count;

        if (stream->ops->copy) {
                retval = stream->ops->copy(stream, buf, avail);
        } else {
                retval = -ENXIO;
                goto out;
        }
        if (retval > 0)
                stream->runtime->total_bytes_transferred += retval;

out:
        mutex_unlock(&stream->device->lock);
        return retval;
}

static int snd_compr_mmap(struct file *f, struct vm_area_struct *vma)
{
        return -ENXIO;
}

static __poll_t snd_compr_get_poll(struct snd_compr_stream *stream)
{
        if (stream->direction == SND_COMPRESS_PLAYBACK)
                return EPOLLOUT | EPOLLWRNORM;
        else
                return EPOLLIN | EPOLLRDNORM;
}

static __poll_t snd_compr_poll(struct file *f, poll_table *wait)
{
        struct snd_compr_file *data = f->private_data;
        struct snd_compr_stream *stream;
        size_t avail;
        __poll_t retval = 0;

        if (snd_BUG_ON(!data))
                return EPOLLERR;

        stream = &data->stream;

        mutex_lock(&stream->device->lock);

        switch (stream->runtime->state) {
        case SNDRV_PCM_STATE_OPEN:
        case SNDRV_PCM_STATE_XRUN:
                retval = snd_compr_get_poll(stream) | EPOLLERR;
                goto out;
        default:
                break;
        }

        poll_wait(f, &stream->runtime->sleep, wait);

        avail = snd_compr_get_avail(stream);
        pr_debug("avail is %ld\n", (unsigned long)avail);
        /* check if we have at least one fragment to fill */
        switch (stream->runtime->state) {
        case SNDRV_PCM_STATE_DRAINING:
                /* stream has been woken up after drain is complete
                 * draining done so set stream state to stopped
                 */
                retval = snd_compr_get_poll(stream);
                stream->runtime->state = SNDRV_PCM_STATE_SETUP;
                break;
        case SNDRV_PCM_STATE_RUNNING:
        case SNDRV_PCM_STATE_PREPARED:
        case SNDRV_PCM_STATE_PAUSED:
                if (avail >= stream->runtime->fragment_size)
                        retval = snd_compr_get_poll(stream);
                break;
        default:
                retval = snd_compr_get_poll(stream) | EPOLLERR;
                break;
        }
out:
        mutex_unlock(&stream->device->lock);
        return retval;
}

static int
snd_compr_get_caps(struct snd_compr_stream *stream, unsigned long arg)
{
        int retval;
        struct snd_compr_caps caps;

        if (!stream->ops->get_caps)
                return -ENXIO;

        memset(&caps, 0, sizeof(caps));
        retval = stream->ops->get_caps(stream, &caps);
        if (retval)
                goto out;
        if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
                retval = -EFAULT;
out:
        return retval;
}

#ifndef COMPR_CODEC_CAPS_OVERFLOW
static int
snd_compr_get_codec_caps(struct snd_compr_stream *stream, unsigned long arg)
{
        int retval;
        struct snd_compr_codec_caps *caps;

        if (!stream->ops->get_codec_caps)
                return -ENXIO;

        caps = kzalloc(sizeof(*caps), GFP_KERNEL);
        if (!caps)
                return -ENOMEM;

        retval = stream->ops->get_codec_caps(stream, caps);
        if (retval)
                goto out;
        if (copy_to_user((void __user *)arg, caps, sizeof(*caps)))
                retval = -EFAULT;

out:
        kfree(caps);
        return retval;
}
#endif /* !COMPR_CODEC_CAPS_OVERFLOW */

/* revisit this with snd_pcm_preallocate_xxx */
static int snd_compr_allocate_buffer(struct snd_compr_stream *stream,
                struct snd_compr_params *params)
{
        unsigned int buffer_size;
        void *buffer = NULL;

        buffer_size = params->buffer.fragment_size * params->buffer.fragments;
        if (stream->ops->copy) {
                buffer = NULL;
                /* if copy is defined the driver will be required to copy
                 * the data from core
                 */
        } else {
                if (stream->runtime->dma_buffer_p) {

                        if (buffer_size > stream->runtime->dma_buffer_p->bytes)
                                dev_err(&stream->device->dev,
                                                "Not enough DMA buffer");
                        else
                                buffer = stream->runtime->dma_buffer_p->area;

                } else {
                        buffer = kmalloc(buffer_size, GFP_KERNEL);
                }

                if (!buffer)
                        return -ENOMEM;
        }
        stream->runtime->fragment_size = params->buffer.fragment_size;
        stream->runtime->fragments = params->buffer.fragments;
        stream->runtime->buffer = buffer;
        stream->runtime->buffer_size = buffer_size;
        return 0;
}

static int snd_compress_check_input(struct snd_compr_params *params)
{
        /* first let's check the buffer parameter's */
        if (params->buffer.fragment_size == 0 ||
            params->buffer.fragments > INT_MAX / params->buffer.fragment_size ||
            params->buffer.fragments == 0)
                return -EINVAL;

        /* now codec parameters */
        if (params->codec.id == 0 || params->codec.id > SND_AUDIOCODEC_MAX)
                return -EINVAL;

        if (params->codec.ch_in == 0 || params->codec.ch_out == 0)
                return -EINVAL;

        return 0;
}

static int
snd_compr_set_params(struct snd_compr_stream *stream, unsigned long arg)
{
        struct snd_compr_params *params;
        int retval;

        if (stream->runtime->state == SNDRV_PCM_STATE_OPEN) {
                /*
                 * we should allow parameter change only when stream has been
                 * opened not in other cases
                 */
                params = memdup_user((void __user *)arg, sizeof(*params));
                if (IS_ERR(params))
                        return PTR_ERR(params);

                retval = snd_compress_check_input(params);
                if (retval)
                        goto out;

                retval = snd_compr_allocate_buffer(stream, params);
                if (retval) {
                        retval = -ENOMEM;
                        goto out;
                }

                retval = stream->ops->set_params(stream, params);
                if (retval)
                        goto out;

                stream->metadata_set = false;
                stream->next_track = false;

                if (stream->direction == SND_COMPRESS_PLAYBACK)
                        stream->runtime->state = SNDRV_PCM_STATE_SETUP;
                else
                        stream->runtime->state = SNDRV_PCM_STATE_PREPARED;
        } else {
                return -EPERM;
        }
out:
        kfree(params);
        return retval;
}

static int
snd_compr_get_params(struct snd_compr_stream *stream, unsigned long arg)
{
        struct snd_codec *params;
        int retval;

        if (!stream->ops->get_params)
                return -EBADFD;

        params = kzalloc(sizeof(*params), GFP_KERNEL);
        if (!params)
                return -ENOMEM;
        retval = stream->ops->get_params(stream, params);
        if (retval)
                goto out;
        if (copy_to_user((char __user *)arg, params, sizeof(*params)))
                retval = -EFAULT;

out:
        kfree(params);
        return retval;
}

static int
snd_compr_get_metadata(struct snd_compr_stream *stream, unsigned long arg)
{
        struct snd_compr_metadata metadata;
        int retval;

        if (!stream->ops->get_metadata)
                return -ENXIO;

        if (copy_from_user(&metadata, (void __user *)arg, sizeof(metadata)))
                return -EFAULT;

        retval = stream->ops->get_metadata(stream, &metadata);
        if (retval != 0)
                return retval;

        if (copy_to_user((void __user *)arg, &metadata, sizeof(metadata)))
                return -EFAULT;

        return 0;
}

static int
snd_compr_set_metadata(struct snd_compr_stream *stream, unsigned long arg)
{
        struct snd_compr_metadata metadata;
        int retval;

        if (!stream->ops->set_metadata)
                return -ENXIO;
        /*
        * we should allow parameter change only when stream has been
        * opened not in other cases
        */
        if (copy_from_user(&metadata, (void __user *)arg, sizeof(metadata)))
                return -EFAULT;

        retval = stream->ops->set_metadata(stream, &metadata);
        stream->metadata_set = true;

        return retval;
}

static inline int
snd_compr_tstamp(struct snd_compr_stream *stream, unsigned long arg)
{
        struct snd_compr_tstamp tstamp = {0};
        int ret;

        ret = snd_compr_update_tstamp(stream, &tstamp);
        if (ret == 0)
                ret = copy_to_user((struct snd_compr_tstamp __user *)arg,
                        &tstamp, sizeof(tstamp)) ? -EFAULT : 0;
        return ret;
}

static int snd_compr_pause(struct snd_compr_stream *stream)
{
        int retval;

        if (stream->runtime->state != SNDRV_PCM_STATE_RUNNING)
                return -EPERM;
        retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_PAUSE_PUSH);
        if (!retval)
                stream->runtime->state = SNDRV_PCM_STATE_PAUSED;
        return retval;
}

static int snd_compr_resume(struct snd_compr_stream *stream)
{
        int retval;

        if (stream->runtime->state != SNDRV_PCM_STATE_PAUSED)
                return -EPERM;
        retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_PAUSE_RELEASE);
        if (!retval)
                stream->runtime->state = SNDRV_PCM_STATE_RUNNING;
        return retval;
}

static int snd_compr_start(struct snd_compr_stream *stream)
{
        int retval;

        if (stream->runtime->state != SNDRV_PCM_STATE_PREPARED)
                return -EPERM;
        retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_START);
        if (!retval)
                stream->runtime->state = SNDRV_PCM_STATE_RUNNING;
        return retval;
}

static int snd_compr_stop(struct snd_compr_stream *stream)
{
        int retval;

        if (stream->runtime->state == SNDRV_PCM_STATE_PREPARED ||
                        stream->runtime->state == SNDRV_PCM_STATE_SETUP)
                return -EPERM;
        retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_STOP);
        if (!retval) {
                snd_compr_drain_notify(stream);
                stream->runtime->total_bytes_available = 0;
                stream->runtime->total_bytes_transferred = 0;
        }
        return retval;
}

static void error_delayed_work(struct work_struct *work)
{
        struct snd_compr_stream *stream;

        stream = container_of(work, struct snd_compr_stream, error_work.work);

        mutex_lock(&stream->device->lock);

        stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_STOP);
        wake_up(&stream->runtime->sleep);

        mutex_unlock(&stream->device->lock);
}

/*
 * snd_compr_stop_error: Report a fatal error on a stream
 * @stream: pointer to stream
 * @state: state to transition the stream to
 *
 * Stop the stream and set its state.
 *
 * Should be called with compressed device lock held.
 */
int snd_compr_stop_error(struct snd_compr_stream *stream,
                         snd_pcm_state_t state)
{
        if (stream->runtime->state == state)
                return 0;

        stream->runtime->state = state;

        pr_debug("Changing state to: %d\n", state);

        queue_delayed_work(system_power_efficient_wq, &stream->error_work, 0);

        return 0;
}
EXPORT_SYMBOL_GPL(snd_compr_stop_error);

static int snd_compress_wait_for_drain(struct snd_compr_stream *stream)
{
        int ret;

        /*
         * We are called with lock held. So drop the lock while we wait for
         * drain complete notification from the driver
         *
         * It is expected that driver will notify the drain completion and then
         * stream will be moved to SETUP state, even if draining resulted in an
         * error. We can trigger next track after this.
         */
        stream->runtime->state = SNDRV_PCM_STATE_DRAINING;
        mutex_unlock(&stream->device->lock);

        /* we wait for drain to complete here, drain can return when
         * interruption occurred, wait returned error or success.
         * For the first two cases we don't do anything different here and
         * return after waking up
         */

        ret = wait_event_interruptible(stream->runtime->sleep,
                        (stream->runtime->state != SNDRV_PCM_STATE_DRAINING));
        if (ret == -ERESTARTSYS)
                pr_debug("wait aborted by a signal\n");
        else if (ret)
                pr_debug("wait for drain failed with %d\n", ret);


        wake_up(&stream->runtime->sleep);
        mutex_lock(&stream->device->lock);

        return ret;
}

static int snd_compr_drain(struct snd_compr_stream *stream)
{
        int retval;

        if (stream->runtime->state == SNDRV_PCM_STATE_PREPARED ||
                        stream->runtime->state == SNDRV_PCM_STATE_SETUP)
                return -EPERM;

        retval = stream->ops->trigger(stream, SND_COMPR_TRIGGER_DRAIN);
        if (retval) {
                pr_debug("SND_COMPR_TRIGGER_DRAIN failed %d\n", retval);
                wake_up(&stream->runtime->sleep);
                return retval;
        }

        return snd_compress_wait_for_drain(stream);
}

static int snd_compr_next_track(struct snd_compr_stream *stream)
{
        int retval;

        /* only a running stream can transition to next track */
        if (stream->runtime->state != SNDRV_PCM_STATE_RUNNING)
                return -EPERM;

        /* you can signal next track if this is intended to be a gapless stream
         * and current track metadata is set
         */
        if (stream->metadata_set == false)
                return -EPERM;

        retval = stream->ops->trigger(stream, SND_COMPR_TRIGGER_NEXT_TRACK);
        if (retval != 0)
                return retval;
        stream->metadata_set = false;
        stream->next_track = true;
        return 0;
}

static int snd_compr_partial_drain(struct snd_compr_stream *stream)
{
        int retval;
        if (stream->runtime->state == SNDRV_PCM_STATE_PREPARED ||
                        stream->runtime->state == SNDRV_PCM_STATE_SETUP)
                return -EPERM;
        /* stream can be drained only when next track has been signalled */
        if (stream->next_track == false)
                return -EPERM;

        retval = stream->ops->trigger(stream, SND_COMPR_TRIGGER_PARTIAL_DRAIN);
        if (retval) {
                pr_debug("Partial drain returned failure\n");
                wake_up(&stream->runtime->sleep);
                return retval;
        }

        stream->next_track = false;
        return snd_compress_wait_for_drain(stream);
}

static long snd_compr_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
{
        struct snd_compr_file *data = f->private_data;
        struct snd_compr_stream *stream;
        int retval = -ENOTTY;

        if (snd_BUG_ON(!data))
                return -EFAULT;

        stream = &data->stream;

        mutex_lock(&stream->device->lock);
        switch (_IOC_NR(cmd)) {
        case _IOC_NR(SNDRV_COMPRESS_IOCTL_VERSION):
                retval = put_user(SNDRV_COMPRESS_VERSION,
                                (int __user *)arg) ? -EFAULT : 0;
                break;
        case _IOC_NR(SNDRV_COMPRESS_GET_CAPS):
                retval = snd_compr_get_caps(stream, arg);
                break;
#ifndef COMPR_CODEC_CAPS_OVERFLOW
        case _IOC_NR(SNDRV_COMPRESS_GET_CODEC_CAPS):
                retval = snd_compr_get_codec_caps(stream, arg);
                break;
#endif
        case _IOC_NR(SNDRV_COMPRESS_SET_PARAMS):
                retval = snd_compr_set_params(stream, arg);
                break;
        case _IOC_NR(SNDRV_COMPRESS_GET_PARAMS):
                retval = snd_compr_get_params(stream, arg);
                break;
        case _IOC_NR(SNDRV_COMPRESS_SET_METADATA):
                retval = snd_compr_set_metadata(stream, arg);
                break;
        case _IOC_NR(SNDRV_COMPRESS_GET_METADATA):
                retval = snd_compr_get_metadata(stream, arg);
                break;
        case _IOC_NR(SNDRV_COMPRESS_TSTAMP):
                retval = snd_compr_tstamp(stream, arg);
                break;
        case _IOC_NR(SNDRV_COMPRESS_AVAIL):
                retval = snd_compr_ioctl_avail(stream, arg);
                break;
        case _IOC_NR(SNDRV_COMPRESS_PAUSE):
                retval = snd_compr_pause(stream);
                break;
        case _IOC_NR(SNDRV_COMPRESS_RESUME):
                retval = snd_compr_resume(stream);
                break;
        case _IOC_NR(SNDRV_COMPRESS_START):
                retval = snd_compr_start(stream);
                break;
        case _IOC_NR(SNDRV_COMPRESS_STOP):
                retval = snd_compr_stop(stream);
                break;
        case _IOC_NR(SNDRV_COMPRESS_DRAIN):
                retval = snd_compr_drain(stream);
                break;
        case _IOC_NR(SNDRV_COMPRESS_PARTIAL_DRAIN):
                retval = snd_compr_partial_drain(stream);
                break;
        case _IOC_NR(SNDRV_COMPRESS_NEXT_TRACK):
                retval = snd_compr_next_track(stream);
                break;

        }
        mutex_unlock(&stream->device->lock);
        return retval;
}

/* support of 32bit userspace on 64bit platforms */
#ifdef CONFIG_COMPAT
static long snd_compr_ioctl_compat(struct file *file, unsigned int cmd,
                                                unsigned long arg)
{
        return snd_compr_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static const struct file_operations snd_compr_file_ops = {
                .owner =        THIS_MODULE,
                .open =         snd_compr_open,
                .release =      snd_compr_free,
                .write =        snd_compr_write,
                .read =         snd_compr_read,
                .unlocked_ioctl = snd_compr_ioctl,
#ifdef CONFIG_COMPAT
                .compat_ioctl = snd_compr_ioctl_compat,
#endif
                .mmap =         snd_compr_mmap,
                .poll =         snd_compr_poll,
};

static int snd_compress_dev_register(struct snd_device *device)
{
        int ret = -EINVAL;
        struct snd_compr *compr;

        if (snd_BUG_ON(!device || !device->device_data))
                return -EBADFD;
        compr = device->device_data;

        pr_debug("reg device %s, direction %d\n", compr->name,
                        compr->direction);
        /* register compressed device */
        ret = snd_register_device(SNDRV_DEVICE_TYPE_COMPRESS,
                                  compr->card, compr->device,
                                  &snd_compr_file_ops, compr, &compr->dev);
        if (ret < 0) {
                pr_err("snd_register_device failed %d\n", ret);
                return ret;
        }
        return ret;

}

static int snd_compress_dev_disconnect(struct snd_device *device)
{
        struct snd_compr *compr;

        compr = device->device_data;
        snd_unregister_device(&compr->dev);
        return 0;
}

#ifdef CONFIG_SND_VERBOSE_PROCFS
static void snd_compress_proc_info_read(struct snd_info_entry *entry,
                                        struct snd_info_buffer *buffer)
{
        struct snd_compr *compr = (struct snd_compr *)entry->private_data;

        snd_iprintf(buffer, "card: %d\n", compr->card->number);
        snd_iprintf(buffer, "device: %d\n", compr->device);

        snd_iprintf(buffer, "stream: %s\n",
                        compr->direction == SND_COMPRESS_PLAYBACK
                                ? "PLAYBACK" : "CAPTURE");
        snd_iprintf(buffer, "id: %s\n", compr->id);
}

static int snd_compress_proc_init(struct snd_compr *compr)
{
        struct snd_info_entry *entry;
        char name[16];

        sprintf(name, "compr%i", compr->device);
        entry = snd_info_create_card_entry(compr->card, name,
                                           compr->card->proc_root);
        if (!entry)
                return -ENOMEM;
        entry->mode = S_IFDIR | 0555;
        compr->proc_root = entry;

        entry = snd_info_create_card_entry(compr->card, "info",
                                           compr->proc_root);
        if (entry)
                snd_info_set_text_ops(entry, compr,
                                      snd_compress_proc_info_read);
        compr->proc_info_entry = entry;

        return 0;
}

static void snd_compress_proc_done(struct snd_compr *compr)
{
        snd_info_free_entry(compr->proc_info_entry);
        compr->proc_info_entry = NULL;
        snd_info_free_entry(compr->proc_root);
        compr->proc_root = NULL;
}

static inline void snd_compress_set_id(struct snd_compr *compr, const char *id)
{
        strlcpy(compr->id, id, sizeof(compr->id));
}
#else
static inline int snd_compress_proc_init(struct snd_compr *compr)
{
        return 0;
}

static inline void snd_compress_proc_done(struct snd_compr *compr)
{
}

static inline void snd_compress_set_id(struct snd_compr *compr, const char *id)
{
}
#endif

static int snd_compress_dev_free(struct snd_device *device)
{
        struct snd_compr *compr;

        compr = device->device_data;
        snd_compress_proc_done(compr);
        put_device(&compr->dev);
        return 0;
}

/*
 * snd_compress_new: create new compress device
 * @card: sound card pointer
 * @device: device number
 * @dirn: device direction, should be of type enum snd_compr_direction
 * @compr: compress device pointer
 */
int snd_compress_new(struct snd_card *card, int device,
                        int dirn, const char *id, struct snd_compr *compr)
{
        static struct snd_device_ops ops = {
                .dev_free = snd_compress_dev_free,
                .dev_register = snd_compress_dev_register,
                .dev_disconnect = snd_compress_dev_disconnect,
        };
        int ret;

        compr->card = card;
        compr->device = device;
        compr->direction = dirn;

        snd_compress_set_id(compr, id);

        snd_device_initialize(&compr->dev, card);
        dev_set_name(&compr->dev, "comprC%iD%i", card->number, device);

        ret = snd_device_new(card, SNDRV_DEV_COMPRESS, compr, &ops);
        if (ret == 0)
                snd_compress_proc_init(compr);

        return ret;
}
EXPORT_SYMBOL_GPL(snd_compress_new);

static int snd_compress_add_device(struct snd_compr *device)
{
        int ret;

        if (!device->card)
                return -EINVAL;

        /* register the card */
        ret = snd_card_register(device->card);
        if (ret)
                goto out;
        return 0;

out:
        pr_err("failed with %d\n", ret);
        return ret;

}

static int snd_compress_remove_device(struct snd_compr *device)
{
        return snd_card_free(device->card);
}

/**
 * snd_compress_register - register compressed device
 *
 * @device: compressed device to register
 */
int snd_compress_register(struct snd_compr *device)
{
        int retval;

        if (device->name == NULL || device->ops == NULL)
                return -EINVAL;

        pr_debug("Registering compressed device %s\n", device->name);
        if (snd_BUG_ON(!device->ops->open))
                return -EINVAL;
        if (snd_BUG_ON(!device->ops->free))
                return -EINVAL;
        if (snd_BUG_ON(!device->ops->set_params))
                return -EINVAL;
        if (snd_BUG_ON(!device->ops->trigger))
                return -EINVAL;

        mutex_init(&device->lock);

        /* register a compressed card */
        mutex_lock(&device_mutex);
        retval = snd_compress_add_device(device);
        mutex_unlock(&device_mutex);
        return retval;
}
EXPORT_SYMBOL_GPL(snd_compress_register);

int snd_compress_deregister(struct snd_compr *device)
{
        pr_debug("Removing compressed device %s\n", device->name);
        mutex_lock(&device_mutex);
        snd_compress_remove_device(device);
        mutex_unlock(&device_mutex);
        return 0;
}
EXPORT_SYMBOL_GPL(snd_compress_deregister);

MODULE_DESCRIPTION("ALSA Compressed offload framework");
MODULE_AUTHOR("Vinod Koul <vinod.koul@linux.intel.com>");
MODULE_LICENSE("GPL v2");