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 \*--------------------------------------------------------------------------*/
  33 static 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  */
  52 static 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_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
  77 static 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
 105 static 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
 111 int atmel_pcm_dma_platform_register(struct device *dev)
 112 {
 113         return devm_snd_dmaengine_pcm_register(dev,
 114                                         &atmel_dmaengine_pcm_config, 0);
 115 }
 116 EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
 117
 118 MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
 119 MODULE_DESCRIPTION("Atmel DMA based PCM module");
 120 MODULE_LICENSE("GPL");