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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