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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * atmel-pcm-dma.c -- ALSA PCM DMA support for the Atmel SoC.4 *5 * Copyright (C) 2012 Atmel6 *7 * Author: Bo Shen <voice.shen@atmel.com>8 *9 * Based on atmel-pcm by:10 * Sedji Gaouaou <sedji.gaouaou@atmel.com>11 * Copyright 2008 Atmel12 */13 14#include <linux/module.h>15#include <linux/init.h>16#include <linux/platform_device.h>17#include <linux/slab.h>18#include <linux/dma-mapping.h>19#include <linux/dmaengine.h>20#include <linux/atmel-ssc.h>21 22#include <sound/core.h>23#include <sound/pcm.h>24#include <sound/pcm_params.h>25#include <sound/soc.h>26#include <sound/dmaengine_pcm.h>27 28#include "atmel-pcm.h"29 30/*--------------------------------------------------------------------------*\31 * Hardware definition32\*--------------------------------------------------------------------------*/33static const struct snd_pcm_hardware atmel_pcm_dma_hardware = {34 .info = SNDRV_PCM_INFO_MMAP |35 SNDRV_PCM_INFO_MMAP_VALID |36 SNDRV_PCM_INFO_INTERLEAVED |37 SNDRV_PCM_INFO_RESUME |38 SNDRV_PCM_INFO_PAUSE,39 .period_bytes_min = 256, /* lighting DMA overhead */40 .period_bytes_max = 2 * 0xffff, /* if 2 bytes format */41 .periods_min = 8,42 .periods_max = 1024, /* no limit */43 .buffer_bytes_max = 512 * 1024,44};45 46/*47 * atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC48 *49 * We use DMAENGINE to send/receive data to/from SSC so this ISR is only to50 * check if any overrun occured.51 */52static void atmel_pcm_dma_irq(u32 ssc_sr,53 struct snd_pcm_substream *substream)54{55 struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);56 struct atmel_pcm_dma_params *prtd;57 58 prtd = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);59 60 if (ssc_sr & prtd->mask->ssc_error) {61 if (snd_pcm_running(substream))62 pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",63 substream->stream == SNDRV_PCM_STREAM_PLAYBACK64 ? "underrun" : "overrun", prtd->name,65 ssc_sr);66 67 /* stop RX and capture: will be enabled again at restart */68 ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);69 snd_pcm_stop_xrun(substream);70 71 /* now drain RHR and read status to remove xrun condition */72 ssc_readx(prtd->ssc->regs, SSC_RHR);73 ssc_readx(prtd->ssc->regs, SSC_SR);74 }75}76 77static int atmel_pcm_configure_dma(struct snd_pcm_substream *substream,78 struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)79{80 struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);81 struct atmel_pcm_dma_params *prtd;82 struct ssc_device *ssc;83 int ret;84 85 prtd = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);86 ssc = prtd->ssc;87 88 ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);89 if (ret) {90 pr_err("atmel-pcm: hwparams to dma slave configure failed\n");91 return ret;92 }93 94 slave_config->dst_addr = ssc->phybase + SSC_THR;95 slave_config->dst_maxburst = 1;96 97 slave_config->src_addr = ssc->phybase + SSC_RHR;98 slave_config->src_maxburst = 1;99 100 prtd->dma_intr_handler = atmel_pcm_dma_irq;101 102 return 0;103}104 105static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {106 .prepare_slave_config = atmel_pcm_configure_dma,107 .pcm_hardware = &atmel_pcm_dma_hardware,108 .prealloc_buffer_size = 64 * 1024,109};110 111int atmel_pcm_dma_platform_register(struct device *dev)112{113 return devm_snd_dmaengine_pcm_register(dev,114 &atmel_dmaengine_pcm_config, 0);115}116EXPORT_SYMBOL(atmel_pcm_dma_platform_register);117 118MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");119MODULE_DESCRIPTION("Atmel DMA based PCM module");120MODULE_LICENSE("GPL");121