text: // SPDX-License-Identifier: GPL-2.0
  //
  // Freescale ASRC ALSA SoC Platform (DMA) driver
  //
  // Copyright (C) 2014 Freescale Semiconductor, Inc.
  //
  // Author: Nicolin Chen <nicoleotsuka@gmail.com>
  
  #include <linux/dma-mapping.h>
  #include <linux/module.h>
  #include <linux/platform_data/dma-imx.h>
  #include <sound/dmaengine_pcm.h>
  #include <sound/pcm_params.h>
  
  #include "fsl_asrc_common.h"
  
  #define FSL_ASRC_DMABUF_SIZE	(256 * 1024)
  
  static struct snd_pcm_hardware snd_imx_hardware = {
  	.info = SNDRV_PCM_INFO_INTERLEAVED |
  		SNDRV_PCM_INFO_BLOCK_TRANSFER |
  		SNDRV_PCM_INFO_MMAP |
  		SNDRV_PCM_INFO_MMAP_VALID,
  	.buffer_bytes_max = FSL_ASRC_DMABUF_SIZE,
  	.period_bytes_min = 128,
  	.period_bytes_max = 65535, /* Limited by SDMA engine */
  	.periods_min = 2,
  	.periods_max = 255,
  	.fifo_size = 0,
  };
  
  static bool filter(struct dma_chan *chan, void *param)
  {
  	if (!imx_dma_is_general_purpose(chan))
  		return false;
  
  	chan->private = param;
  
  	return true;
  }
  
  static void fsl_asrc_dma_complete(void *arg)
  {
  	struct snd_pcm_substream *substream = arg;
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct fsl_asrc_pair *pair = runtime->private_data;
  
  	pair->pos += snd_pcm_lib_period_bytes(substream);
  	if (pair->pos >= snd_pcm_lib_buffer_bytes(substream))
  		pair->pos = 0;
  
  	snd_pcm_period_elapsed(substream);
  }
  
  static int fsl_asrc_dma_prepare_and_submit(struct snd_pcm_substream *substream,
  					   struct snd_soc_component *component)
  {
  	u8 dir = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? OUT : IN;
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct fsl_asrc_pair *pair = runtime->private_data;
  	struct device *dev = component->dev;
  	unsigned long flags = DMA_CTRL_ACK;
  
  	/* Prepare and submit Front-End DMA channel */
  	if (!substream->runtime->no_period_wakeup)
  		flags |= DMA_PREP_INTERRUPT;
  
  	pair->pos = 0;
  	pair->desc[!dir] = dmaengine_prep_dma_cyclic(
  			pair->dma_chan[!dir], runtime->dma_addr,
  			snd_pcm_lib_buffer_bytes(substream),
  			snd_pcm_lib_period_bytes(substream),
  			dir == OUT ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM, flags);
  	if (!pair->desc[!dir]) {
  		dev_err(dev, "failed to prepare slave DMA for Front-End\n");
  		return -ENOMEM;
  	}
  
  	pair->desc[!dir]->callback = fsl_asrc_dma_complete;
  	pair->desc[!dir]->callback_param = substream;
  
  	dmaengine_submit(pair->desc[!dir]);
  
  	/* Prepare and submit Back-End DMA channel */
  	pair->desc[dir] = dmaengine_prep_dma_cyclic(
  			pair->dma_chan[dir], 0xffff, 64, 64, DMA_DEV_TO_DEV, 0);
  	if (!pair->desc[dir]) {
  		dev_err(dev, "failed to prepare slave DMA for Back-End\n");
  		return -ENOMEM;
  	}
  
  	dmaengine_submit(pair->desc[dir]);
  
  	return 0;
  }
  
  static int fsl_asrc_dma_trigger(struct snd_soc_component *component,
  				struct snd_pcm_substream *substream, int cmd)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct fsl_asrc_pair *pair = runtime->private_data;
  	int ret;
  
  	switch (cmd) {
  	case SNDRV_PCM_TRIGGER_START:
  	case SNDRV_PCM_TRIGGER_RESUME:
  	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
  		ret = fsl_asrc_dma_prepare_and_submit(substream, component);
  		if (ret)
  			return ret;
  		dma_async_issue_pending(pair->dma_chan[IN]);
  		dma_async_issue_pending(pair->dma_chan[OUT]);
  		break;
  	case SNDRV_PCM_TRIGGER_STOP:
  	case SNDRV_PCM_TRIGGER_SUSPEND:
  	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
  		dmaengine_terminate_all(pair->dma_chan[OUT]);
  		dmaengine_terminate_all(pair->dma_chan[IN]);
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static int fsl_asrc_dma_hw_params(struct snd_soc_component *component,
  				  struct snd_pcm_substream *substream,
  				  struct snd_pcm_hw_params *params)
  {
  	enum dma_slave_buswidth buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
  	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
  	bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
  	struct snd_dmaengine_dai_dma_data *dma_params_fe = NULL;
  	struct snd_dmaengine_dai_dma_data *dma_params_be = NULL;
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct fsl_asrc_pair *pair = runtime->private_data;
  	struct dma_chan *tmp_chan = NULL, *be_chan = NULL;
  	struct snd_soc_component *component_be = NULL;
  	struct fsl_asrc *asrc = pair->asrc;
  	struct dma_slave_config config_fe, config_be;
  	enum asrc_pair_index index = pair->index;
  	struct device *dev = component->dev;
  	struct device_node *of_dma_node;
  	int stream = substream->stream;
  	struct imx_dma_data *tmp_data;
  	struct snd_soc_dpcm *dpcm;
  	struct device *dev_be;
  	u8 dir = tx ? OUT : IN;
  	dma_cap_mask_t mask;
  	int ret, width;
  
  	/* Fetch the Back-End dma_data from DPCM */
  	for_each_dpcm_be(rtd, stream, dpcm) {
  		struct snd_soc_pcm_runtime *be = dpcm->be;
  		struct snd_pcm_substream *substream_be;
  		struct snd_soc_dai *dai = asoc_rtd_to_cpu(be, 0);
  
  		if (dpcm->fe != rtd)
  			continue;
  
  		substream_be = snd_soc_dpcm_get_substream(be, stream);
  		dma_params_be = snd_soc_dai_get_dma_data(dai, substream_be);
  		dev_be = dai->dev;
  		break;
  	}
  
  	if (!dma_params_be) {
  		dev_err(dev, "failed to get the substream of Back-End\n");
  		return -EINVAL;
  	}
  
  	/* Override dma_data of the Front-End and config its dmaengine */
  	dma_params_fe = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
  	dma_params_fe->addr = asrc->paddr + asrc->get_fifo_addr(!dir, index);
  	dma_params_fe->maxburst = dma_params_be->maxburst;
  
  	pair->dma_chan[!dir] = asrc->get_dma_channel(pair, !dir);
  	if (!pair->dma_chan[!dir]) {
  		dev_err(dev, "failed to request DMA channel\n");
  		return -EINVAL;
  	}
  
  	memset(&config_fe, 0, sizeof(config_fe));
  	ret = snd_dmaengine_pcm_prepare_slave_config(substream, params, &config_fe);
  	if (ret) {
  		dev_err(dev, "failed to prepare DMA config for Front-End\n");
  		return ret;
  	}
  
  	ret = dmaengine_slave_config(pair->dma_chan[!dir], &config_fe);
  	if (ret) {
  		dev_err(dev, "failed to config DMA channel for Front-End\n");
  		return ret;
  	}
  
  	/* Request and config DMA channel for Back-End */
  	dma_cap_zero(mask);
  	dma_cap_set(DMA_SLAVE, mask);
  	dma_cap_set(DMA_CYCLIC, mask);
  
  	/*
  	 * The Back-End device might have already requested a DMA channel,
  	 * so try to reuse it first, and then request a new one upon NULL.
  	 */
  	component_be = snd_soc_lookup_component_nolocked(dev_be, SND_DMAENGINE_PCM_DRV_NAME);
  	if (component_be) {
  		be_chan = soc_component_to_pcm(component_be)->chan[substream->stream];
  		tmp_chan = be_chan;
  	}
  	if (!tmp_chan)
  		tmp_chan = dma_request_slave_channel(dev_be, tx ? "tx" : "rx");
  
  	/*
  	 * An EDMA DEV_TO_DEV channel is fixed and bound with DMA event of each
  	 * peripheral, unlike SDMA channel that is allocated dynamically. So no
  	 * need to configure dma_request and dma_request2, but get dma_chan of
  	 * Back-End device directly via dma_request_slave_channel.
  	 */
  	if (!asrc->use_edma) {
  		/* Get DMA request of Back-End */
  		tmp_data = tmp_chan->private;
  		pair->dma_data.dma_request = tmp_data->dma_request;
  		if (!be_chan)
  			dma_release_channel(tmp_chan);
  
  		/* Get DMA request of Front-End */
  		tmp_chan = asrc->get_dma_channel(pair, dir);
  		tmp_data = tmp_chan->private;
  		pair->dma_data.dma_request2 = tmp_data->dma_request;
  		pair->dma_data.peripheral_type = tmp_data->peripheral_type;
  		pair->dma_data.priority = tmp_data->priority;
  		dma_release_channel(tmp_chan);
  
  		of_dma_node = pair->dma_chan[!dir]->device->dev->of_node;
  		pair->dma_chan[dir] =
  			__dma_request_channel(&mask, filter, &pair->dma_data,
  					      of_dma_node);
  		pair->req_dma_chan = true;
  	} else {
  		pair->dma_chan[dir] = tmp_chan;
  		/* Do not flag to release if we are reusing the Back-End one */
  		pair->req_dma_chan = !be_chan;
  	}
  
  	if (!pair->dma_chan[dir]) {
  		dev_err(dev, "failed to request DMA channel for Back-End\n");
  		return -EINVAL;
  	}
  
  	width = snd_pcm_format_physical_width(asrc->asrc_format);
  	if (width < 8 || width > 64)
  		return -EINVAL;
  	else if (width == 8)
  		buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
  	else if (width == 16)
  		buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
  	else if (width == 24)
  		buswidth = DMA_SLAVE_BUSWIDTH_3_BYTES;
  	else if (width <= 32)
  		buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
  	else
  		buswidth = DMA_SLAVE_BUSWIDTH_8_BYTES;
  
  	config_be.direction = DMA_DEV_TO_DEV;
  	config_be.src_addr_width = buswidth;
  	config_be.src_maxburst = dma_params_be->maxburst;
  	config_be.dst_addr_width = buswidth;
  	config_be.dst_maxburst = dma_params_be->maxburst;
  
  	if (tx) {
  		config_be.src_addr = asrc->paddr + asrc->get_fifo_addr(OUT, index);
  		config_be.dst_addr = dma_params_be->addr;
  	} else {
  		config_be.dst_addr = asrc->paddr + asrc->get_fifo_addr(IN, index);
  		config_be.src_addr = dma_params_be->addr;
  	}
  
  	ret = dmaengine_slave_config(pair->dma_chan[dir], &config_be);
  	if (ret) {
  		dev_err(dev, "failed to config DMA channel for Back-End\n");
  		if (pair->req_dma_chan)
  			dma_release_channel(pair->dma_chan[dir]);
  		return ret;
  	}
  
  	return 0;
  }
  
  static int fsl_asrc_dma_hw_free(struct snd_soc_component *component,
  				struct snd_pcm_substream *substream)
  {
  	bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct fsl_asrc_pair *pair = runtime->private_data;
  	u8 dir = tx ? OUT : IN;
  
  	if (pair->dma_chan[!dir])
  		dma_release_channel(pair->dma_chan[!dir]);
  
  	/* release dev_to_dev chan if we aren't reusing the Back-End one */
  	if (pair->dma_chan[dir] && pair->req_dma_chan)
  		dma_release_channel(pair->dma_chan[dir]);
  
  	pair->dma_chan[!dir] = NULL;
  	pair->dma_chan[dir] = NULL;
  
  	return 0;
  }
  
  static int fsl_asrc_dma_startup(struct snd_soc_component *component,
  				struct snd_pcm_substream *substream)
  {
  	bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
  	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct snd_dmaengine_dai_dma_data *dma_data;
  	struct device *dev = component->dev;
  	struct fsl_asrc *asrc = dev_get_drvdata(dev);
  	struct fsl_asrc_pair *pair;
  	struct dma_chan *tmp_chan = NULL;
  	u8 dir = tx ? OUT : IN;
  	bool release_pair = true;
  	int ret = 0;
  
  	ret = snd_pcm_hw_constraint_integer(substream->runtime,
  					    SNDRV_PCM_HW_PARAM_PERIODS);
  	if (ret < 0) {
  		dev_err(dev, "failed to set pcm hw params periods\n");
  		return ret;
  	}
  
  	pair = kzalloc(sizeof(*pair) + asrc->pair_priv_size, GFP_KERNEL);
  	if (!pair)
  		return -ENOMEM;
  
  	pair->asrc = asrc;
  	pair->private = (void *)pair + sizeof(struct fsl_asrc_pair);
  
  	runtime->private_data = pair;
  
  	/* Request a dummy pair, which will be released later.
  	 * Request pair function needs channel num as input, for this
  	 * dummy pair, we just request "1" channel temporarily.
  	 */
  	ret = asrc->request_pair(1, pair);
  	if (ret < 0) {
  		dev_err(dev, "failed to request asrc pair\n");
  		goto req_pair_err;
  	}
  
  	/* Request a dummy dma channel, which will be released later. */
  	tmp_chan = asrc->get_dma_channel(pair, dir);
  	if (!tmp_chan) {
  		dev_err(dev, "failed to get dma channel\n");
  		ret = -EINVAL;
  		goto dma_chan_err;
  	}
  
  	dma_data = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
  
  	/* Refine the snd_imx_hardware according to caps of DMA. */
  	ret = snd_dmaengine_pcm_refine_runtime_hwparams(substream,
  							dma_data,
  							&snd_imx_hardware,
  							tmp_chan);
  	if (ret < 0) {
  		dev_err(dev, "failed to refine runtime hwparams\n");
  		goto out;
  	}
  
  	release_pair = false;
  	snd_soc_set_runtime_hwparams(substream, &snd_imx_hardware);
  
  out:
  	dma_release_channel(tmp_chan);
  
  dma_chan_err:
  	asrc->release_pair(pair);
  
  req_pair_err:
  	if (release_pair)
  		kfree(pair);
  
  	return ret;
  }
  
  static int fsl_asrc_dma_shutdown(struct snd_soc_component *component,
  				 struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct fsl_asrc_pair *pair = runtime->private_data;
  	struct fsl_asrc *asrc;
  
  	if (!pair)
  		return 0;
  
  	asrc = pair->asrc;
  
  	if (asrc->pair[pair->index] == pair)
  		asrc->pair[pair->index] = NULL;
  
  	kfree(pair);
  
  	return 0;
  }
  
  static snd_pcm_uframes_t
  fsl_asrc_dma_pcm_pointer(struct snd_soc_component *component,
  			 struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct fsl_asrc_pair *pair = runtime->private_data;
  
  	return bytes_to_frames(substream->runtime, pair->pos);
  }
  
  static int fsl_asrc_dma_pcm_new(struct snd_soc_component *component,
  				struct snd_soc_pcm_runtime *rtd)
  {
  	struct snd_card *card = rtd->card->snd_card;
  	struct snd_pcm *pcm = rtd->pcm;
  	int ret;
  
  	ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
  	if (ret) {
  		dev_err(card->dev, "failed to set DMA mask\n");
  		return ret;
  	}
  
  	return snd_pcm_set_fixed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV,
  					    card->dev, FSL_ASRC_DMABUF_SIZE);
  }
  
  struct snd_soc_component_driver fsl_asrc_component = {
  	.name		= DRV_NAME,
  	.hw_params	= fsl_asrc_dma_hw_params,
  	.hw_free	= fsl_asrc_dma_hw_free,
  	.trigger	= fsl_asrc_dma_trigger,
  	.open		= fsl_asrc_dma_startup,
  	.close		= fsl_asrc_dma_shutdown,
  	.pointer	= fsl_asrc_dma_pcm_pointer,
  	.pcm_construct	= fsl_asrc_dma_pcm_new,
  };
  EXPORT_SYMBOL_GPL(fsl_asrc_component);
  