root/sound/soc/atmel/atmel-pcm-dma.c

DEFINITIONS

1. atmel_pcm_dma_irq
2. atmel_pcm_configure_dma
3. atmel_pcm_dma_platform_register

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