/*
   *  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;
  
  	switch (params_format(params)) {
  	case SNDRV_PCM_FORMAT_S8:
  		buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
  		break;
  	case SNDRV_PCM_FORMAT_S16_LE:
  		buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
  		break;
  	case SNDRV_PCM_FORMAT_S18_3LE:
  	case SNDRV_PCM_FORMAT_S20_3LE:
  	case SNDRV_PCM_FORMAT_S24_LE:
  	case SNDRV_PCM_FORMAT_S32_LE:
  		buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	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);
  	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:
  	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 availabe 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 availabe 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");