/*
 *  Copyright (C) 2012, Analog Devices Inc.
 *      Author: Lars-Peter Clausen <lars@metafoo.de>
 *
 *  Based on:
 *      imx-pcm-dma-mx2.c, Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
 *      mxs-pcm.c, Copyright (C) 2011 Freescale Semiconductor, Inc.
 *      ep93xx-pcm.c, Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
 *                    Copyright (C) 2006 Applied Data Systems
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under  the terms of the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the License, or (at your
 *  option) any later version.
 *
 *  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.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/dmaengine.h>
#include <linux/slab.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <sound/dmaengine_pcm.h>

struct dmaengine_pcm_runtime_data {
        struct dma_chan *dma_chan;
        dma_cookie_t cookie;

        unsigned int pos;
};

static inline struct dmaengine_pcm_runtime_data *substream_to_prtd(
        const struct snd_pcm_substream *substream)
{
        return substream->runtime->private_data;
}

struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream)
{
        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

        return prtd->dma_chan;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_chan);

/**
 * snd_hwparams_to_dma_slave_config - Convert hw_params to dma_slave_config
 * @substream: PCM substream
 * @params: hw_params
 * @slave_config: DMA slave config
 *
 * This function can be used to initialize a dma_slave_config from a substream
 * and hw_params in a dmaengine based PCM driver implementation.
 */
int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
        const struct snd_pcm_hw_params *params,
        struct dma_slave_config *slave_config)
{
        enum dma_slave_buswidth buswidth;
        int bits;

        bits = params_physical_width(params);
        if (bits < 8 || bits > 64)
                return -EINVAL;
        else if (bits == 8)
                buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
        else if (bits == 16)
                buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
        else if (bits == 24)
                buswidth = DMA_SLAVE_BUSWIDTH_3_BYTES;
        else if (bits <= 32)
                buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
        else
                buswidth = DMA_SLAVE_BUSWIDTH_8_BYTES;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                slave_config->direction = DMA_MEM_TO_DEV;
                slave_config->dst_addr_width = buswidth;
        } else {
                slave_config->direction = DMA_DEV_TO_MEM;
                slave_config->src_addr_width = buswidth;
        }

        slave_config->device_fc = false;

        return 0;
}
EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);

/**
 * snd_dmaengine_pcm_set_config_from_dai_data() - Initializes a dma slave config
 *  using DAI DMA data.
 * @substream: PCM substream
 * @dma_data: DAI DMA data
 * @slave_config: DMA slave configuration
 *
 * Initializes the {dst,src}_addr, {dst,src}_maxburst, {dst,src}_addr_width and
 * slave_id fields of the DMA slave config from the same fields of the DAI DMA
 * data struct. The src and dst fields will be initialized depending on the
 * direction of the substream. If the substream is a playback stream the dst
 * fields will be initialized, if it is a capture stream the src fields will be
 * initialized. The {dst,src}_addr_width field will only be initialized if the
 * addr_width field of the DAI DMA data struct is not equal to
 * DMA_SLAVE_BUSWIDTH_UNDEFINED.
 */
void snd_dmaengine_pcm_set_config_from_dai_data(
        const struct snd_pcm_substream *substream,
        const struct snd_dmaengine_dai_dma_data *dma_data,
        struct dma_slave_config *slave_config)
{
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                slave_config->dst_addr = dma_data->addr;
                slave_config->dst_maxburst = dma_data->maxburst;
                if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
                        slave_config->dst_addr_width = dma_data->addr_width;
        } else {
                slave_config->src_addr = dma_data->addr;
                slave_config->src_maxburst = dma_data->maxburst;
                if (dma_data->addr_width != DMA_SLAVE_BUSWIDTH_UNDEFINED)
                        slave_config->src_addr_width = dma_data->addr_width;
        }

        slave_config->slave_id = dma_data->slave_id;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_config_from_dai_data);

static void dmaengine_pcm_dma_complete(void *arg)
{
        struct snd_pcm_substream *substream = arg;
        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

        prtd->pos += snd_pcm_lib_period_bytes(substream);
        if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream))
                prtd->pos = 0;

        snd_pcm_period_elapsed(substream);
}

static int dmaengine_pcm_prepare_and_submit(struct snd_pcm_substream *substream)
{
        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
        struct dma_chan *chan = prtd->dma_chan;
        struct dma_async_tx_descriptor *desc;
        enum dma_transfer_direction direction;
        unsigned long flags = DMA_CTRL_ACK;

        direction = snd_pcm_substream_to_dma_direction(substream);

        if (!substream->runtime->no_period_wakeup)
                flags |= DMA_PREP_INTERRUPT;

        prtd->pos = 0;
        desc = dmaengine_prep_dma_cyclic(chan,
                substream->runtime->dma_addr,
                snd_pcm_lib_buffer_bytes(substream),
                snd_pcm_lib_period_bytes(substream), direction, flags);

        if (!desc)
                return -ENOMEM;

        desc->callback = dmaengine_pcm_dma_complete;
        desc->callback_param = substream;
        prtd->cookie = dmaengine_submit(desc);

        return 0;
}

/**
 * snd_dmaengine_pcm_trigger - dmaengine based PCM trigger implementation
 * @substream: PCM substream
 * @cmd: Trigger command
 *
 * Returns 0 on success, a negative error code otherwise.
 *
 * This function can be used as the PCM trigger callback for dmaengine based PCM
 * driver implementations.
 */
int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        int ret;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                ret = dmaengine_pcm_prepare_and_submit(substream);
                if (ret)
                        return ret;
                dma_async_issue_pending(prtd->dma_chan);
                break;
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                dmaengine_resume(prtd->dma_chan);
                break;
        case SNDRV_PCM_TRIGGER_SUSPEND:
                if (runtime->info & SNDRV_PCM_INFO_PAUSE)
                        dmaengine_pause(prtd->dma_chan);
                else
                        dmaengine_terminate_all(prtd->dma_chan);
                break;
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                dmaengine_pause(prtd->dma_chan);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
                dmaengine_terminate_all(prtd->dma_chan);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_trigger);

/**
 * snd_dmaengine_pcm_pointer_no_residue - dmaengine based PCM pointer implementation
 * @substream: PCM substream
 *
 * This function is deprecated and should not be used by new drivers, as its
 * results may be unreliable.
 */
snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream *substream)
{
        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
        return bytes_to_frames(substream->runtime, prtd->pos);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer_no_residue);

/**
 * snd_dmaengine_pcm_pointer - dmaengine based PCM pointer implementation
 * @substream: PCM substream
 *
 * This function can be used as the PCM pointer callback for dmaengine based PCM
 * driver implementations.
 */
snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
{
        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
        struct dma_tx_state state;
        enum dma_status status;
        unsigned int buf_size;
        unsigned int pos = 0;

        status = dmaengine_tx_status(prtd->dma_chan, prtd->cookie, &state);
        if (status == DMA_IN_PROGRESS || status == DMA_PAUSED) {
                buf_size = snd_pcm_lib_buffer_bytes(substream);
                if (state.residue > 0 && state.residue <= buf_size)
                        pos = buf_size - state.residue;
        }

        return bytes_to_frames(substream->runtime, pos);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);

/**
 * snd_dmaengine_pcm_request_channel - Request channel for the dmaengine PCM
 * @filter_fn: Filter function used to request the DMA channel
 * @filter_data: Data passed to the DMA filter function
 *
 * Returns NULL or the requested DMA channel.
 *
 * This function request a DMA channel for usage with dmaengine PCM.
 */
struct dma_chan *snd_dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
        void *filter_data)
{
        dma_cap_mask_t mask;

        dma_cap_zero(mask);
        dma_cap_set(DMA_SLAVE, mask);
        dma_cap_set(DMA_CYCLIC, mask);

        return dma_request_channel(mask, filter_fn, filter_data);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_request_channel);

/**
 * snd_dmaengine_pcm_open - Open a dmaengine based PCM substream
 * @substream: PCM substream
 * @chan: DMA channel to use for data transfers
 *
 * Returns 0 on success, a negative error code otherwise.
 *
 * The function should usually be called from the pcm open callback. Note that
 * this function will use private_data field of the substream's runtime. So it
 * is not available to your pcm driver implementation.
 */
int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
        struct dma_chan *chan)
{
        struct dmaengine_pcm_runtime_data *prtd;
        int ret;

        if (!chan)
                return -ENXIO;

        ret = snd_pcm_hw_constraint_integer(substream->runtime,
                                            SNDRV_PCM_HW_PARAM_PERIODS);
        if (ret < 0)
                return ret;

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

        prtd->dma_chan = chan;

        substream->runtime->private_data = prtd;

        return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);

/**
 * snd_dmaengine_pcm_open_request_chan - Open a dmaengine based PCM substream and request channel
 * @substream: PCM substream
 * @filter_fn: Filter function used to request the DMA channel
 * @filter_data: Data passed to the DMA filter function
 *
 * Returns 0 on success, a negative error code otherwise.
 *
 * This function will request a DMA channel using the passed filter function and
 * data. The function should usually be called from the pcm open callback. Note
 * that this function will use private_data field of the substream's runtime. So
 * it is not available to your pcm driver implementation.
 */
int snd_dmaengine_pcm_open_request_chan(struct snd_pcm_substream *substream,
        dma_filter_fn filter_fn, void *filter_data)
{
        return snd_dmaengine_pcm_open(substream,
                    snd_dmaengine_pcm_request_channel(filter_fn, filter_data));
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open_request_chan);

/**
 * snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
 * @substream: PCM substream
 */
int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
{
        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

        kfree(prtd);

        return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close);

/**
 * snd_dmaengine_pcm_release_chan_close - Close a dmaengine based PCM substream and release channel
 * @substream: PCM substream
 *
 * Releases the DMA channel associated with the PCM substream.
 */
int snd_dmaengine_pcm_close_release_chan(struct snd_pcm_substream *substream)
{
        struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

        dma_release_channel(prtd->dma_chan);

        return snd_dmaengine_pcm_close(substream);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close_release_chan);

MODULE_LICENSE("GPL");