LXR linux/sound/soc/atmel/atmel-pcm-dma.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * atmel-pcm-dma.c  --  ALSA PCM DMA support for the Atmel SoC.
   4 *
   5 *  Copyright (C) 2012 Atmel
   6 *
   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 Atmel
  12 */
  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 definition
  32\*--------------------------------------------------------------------------*/
  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 SSC
  48 *
  49 * We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
  50 * 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 = asoc_substream_to_rtd(substream);
  56        struct atmel_pcm_dma_params *prtd;
  57
  58        prtd = snd_soc_dai_get_dma_data(asoc_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_PLAYBACK
  64                                ? "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 = asoc_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(asoc_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