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The ASoC core assumes that the PCM component of the ASoC card transparently moves data around and does not impose any restrictions on the memory layout or the transfer speed. It ignores all fields from the snd_pcm_hardware struct for the PCM driver that are related to this. Setting these fields in the PCM driver might suggest otherwise though, so rather not set them. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Bo Shen <voice.shen@atmel.com> Signed-off-by: Mark Brown <broonie@linaro.org>
145 lines
4.5 KiB
C
145 lines
4.5 KiB
C
/*
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* atmel-pcm-dma.c -- ALSA PCM DMA support for the Atmel SoC.
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*
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* Copyright (C) 2012 Atmel
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*
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* Author: Bo Shen <voice.shen@atmel.com>
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*
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* Based on atmel-pcm by:
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* Sedji Gaouaou <sedji.gaouaou@atmel.com>
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* Copyright 2008 Atmel
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/dma-mapping.h>
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#include <linux/dmaengine.h>
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#include <linux/atmel-ssc.h>
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#include <linux/platform_data/dma-atmel.h>
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#include <sound/core.h>
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#include <sound/pcm.h>
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#include <sound/pcm_params.h>
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#include <sound/soc.h>
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#include <sound/dmaengine_pcm.h>
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#include "atmel-pcm.h"
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/*--------------------------------------------------------------------------*\
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* Hardware definition
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\*--------------------------------------------------------------------------*/
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static const struct snd_pcm_hardware atmel_pcm_dma_hardware = {
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.info = SNDRV_PCM_INFO_MMAP |
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SNDRV_PCM_INFO_MMAP_VALID |
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SNDRV_PCM_INFO_INTERLEAVED |
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SNDRV_PCM_INFO_RESUME |
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SNDRV_PCM_INFO_PAUSE,
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.period_bytes_min = 256, /* lighting DMA overhead */
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.period_bytes_max = 2 * 0xffff, /* if 2 bytes format */
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.periods_min = 8,
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.periods_max = 1024, /* no limit */
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.buffer_bytes_max = ATMEL_SSC_DMABUF_SIZE,
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};
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/**
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* atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
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*
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* We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
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* check if any overrun occured.
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*/
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static void atmel_pcm_dma_irq(u32 ssc_sr,
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struct snd_pcm_substream *substream)
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{
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struct snd_soc_pcm_runtime *rtd = substream->private_data;
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struct atmel_pcm_dma_params *prtd;
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prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
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if (ssc_sr & prtd->mask->ssc_error) {
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if (snd_pcm_running(substream))
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pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",
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substream->stream == SNDRV_PCM_STREAM_PLAYBACK
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? "underrun" : "overrun", prtd->name,
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ssc_sr);
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/* stop RX and capture: will be enabled again at restart */
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ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);
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snd_pcm_stream_lock(substream);
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snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
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snd_pcm_stream_unlock(substream);
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/* now drain RHR and read status to remove xrun condition */
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ssc_readx(prtd->ssc->regs, SSC_RHR);
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ssc_readx(prtd->ssc->regs, SSC_SR);
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}
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}
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static int atmel_pcm_configure_dma(struct snd_pcm_substream *substream,
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struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
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{
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struct snd_soc_pcm_runtime *rtd = substream->private_data;
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struct atmel_pcm_dma_params *prtd;
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struct ssc_device *ssc;
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int ret;
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prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
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ssc = prtd->ssc;
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ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
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if (ret) {
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pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
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return ret;
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}
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if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
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slave_config->dst_addr = ssc->phybase + SSC_THR;
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slave_config->dst_maxburst = 1;
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} else {
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slave_config->src_addr = ssc->phybase + SSC_RHR;
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slave_config->src_maxburst = 1;
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}
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prtd->dma_intr_handler = atmel_pcm_dma_irq;
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return 0;
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}
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static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {
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.prepare_slave_config = atmel_pcm_configure_dma,
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.pcm_hardware = &atmel_pcm_dma_hardware,
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.prealloc_buffer_size = ATMEL_SSC_DMABUF_SIZE,
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};
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int atmel_pcm_dma_platform_register(struct device *dev)
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{
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return snd_dmaengine_pcm_register(dev, &atmel_dmaengine_pcm_config,
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SND_DMAENGINE_PCM_FLAG_NO_RESIDUE);
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}
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EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
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void atmel_pcm_dma_platform_unregister(struct device *dev)
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{
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snd_dmaengine_pcm_unregister(dev);
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}
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EXPORT_SYMBOL(atmel_pcm_dma_platform_unregister);
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MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
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MODULE_DESCRIPTION("Atmel DMA based PCM module");
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MODULE_LICENSE("GPL");
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