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

   1 /*
   2  * atmel-pcm-dma.c  --  ALSA PCM DMA support for the Atmel SoC.
   3  *
   4  *  Copyright (C) 2012 Atmel
   5  *
   6  * Author: Bo Shen <voice.shen@atmel.com>
   7  *
   8  * Based on atmel-pcm by:
   9  * Sedji Gaouaou <sedji.gaouaou@atmel.com>
  10  * Copyright 2008 Atmel
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/platform_device.h>
  30 #include <linux/slab.h>
  31 #include <linux/dma-mapping.h>
  32 #include <linux/dmaengine.h>
  33 #include <linux/atmel-ssc.h>
  34 #include <linux/platform_data/dma-atmel.h>
  35
  36 #include <sound/core.h>
  37 #include <sound/pcm.h>
  38 #include <sound/pcm_params.h>
  39 #include <sound/soc.h>
  40 #include <sound/dmaengine_pcm.h>
  41
  42 #include "atmel-pcm.h"
  43
  44 /*--------------------------------------------------------------------------*\
  45  * Hardware definition
  46 \*--------------------------------------------------------------------------*/
  47 static const struct snd_pcm_hardware atmel_pcm_dma_hardware = {
  48         .info                   = SNDRV_PCM_INFO_MMAP |
  49                                   SNDRV_PCM_INFO_MMAP_VALID |
  50                                   SNDRV_PCM_INFO_INTERLEAVED |
  51                                   SNDRV_PCM_INFO_RESUME |
  52                                   SNDRV_PCM_INFO_PAUSE,
  53         .period_bytes_min       = 256,          /* lighting DMA overhead */
  54         .period_bytes_max       = 2 * 0xffff,   /* if 2 bytes format */
  55         .periods_min            = 8,
  56         .periods_max            = 1024,         /* no limit */
  57         .buffer_bytes_max       = 512 * 1024,
  58 };
  59
  60 /**
  61  * atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
  62  *
  63  * We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
  64  * check if any overrun occured.
  65  */
  66 static void atmel_pcm_dma_irq(u32 ssc_sr,
  67         struct snd_pcm_substream *substream)
  68 {
  69         struct snd_soc_pcm_runtime *rtd = substream->private_data;
  70         struct atmel_pcm_dma_params *prtd;
  71
  72         prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
  73
  74         if (ssc_sr & prtd->mask->ssc_error) {
  75                 if (snd_pcm_running(substream))
  76                         pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",
  77                                 substream->stream == SNDRV_PCM_STREAM_PLAYBACK
  78                                 ? "underrun" : "overrun", prtd->name,
  79                                 ssc_sr);
  80
  81                 /* stop RX and capture: will be enabled again at restart */
  82                 ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);
  83                 snd_pcm_stop_xrun(substream);
  84
  85                 /* now drain RHR and read status to remove xrun condition */
  86                 ssc_readx(prtd->ssc->regs, SSC_RHR);
  87                 ssc_readx(prtd->ssc->regs, SSC_SR);
  88         }
  89 }
  90
  91 static int atmel_pcm_configure_dma(struct snd_pcm_substream *substream,
  92         struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
  93 {
  94         struct snd_soc_pcm_runtime *rtd = substream->private_data;
  95         struct atmel_pcm_dma_params *prtd;
  96         struct ssc_device *ssc;
  97         int ret;
  98
  99         prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
 100         ssc = prtd->ssc;
 101
 102         ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
 103         if (ret) {
 104                 pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
 105                 return ret;
 106         }
 107
 108         slave_config->dst_addr = ssc->phybase + SSC_THR;
 109         slave_config->dst_maxburst = 1;
 110
 111         slave_config->src_addr = ssc->phybase + SSC_RHR;
 112         slave_config->src_maxburst = 1;
 113
 114         prtd->dma_intr_handler = atmel_pcm_dma_irq;
 115
 116         return 0;
 117 }
 118
 119 static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {
 120         .prepare_slave_config = atmel_pcm_configure_dma,
 121         .pcm_hardware = &atmel_pcm_dma_hardware,
 122         .prealloc_buffer_size = 64 * 1024,
 123 };
 124
 125 int atmel_pcm_dma_platform_register(struct device *dev)
 126 {
 127         return snd_dmaengine_pcm_register(dev, &atmel_dmaengine_pcm_config, 0);
 128 }
 129 EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
 130
 131 void atmel_pcm_dma_platform_unregister(struct device *dev)
 132 {
 133         snd_dmaengine_pcm_unregister(dev);
 134 }
 135 EXPORT_SYMBOL(atmel_pcm_dma_platform_unregister);
 136
 137 MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
 138 MODULE_DESCRIPTION("Atmel DMA based PCM module");
 139 MODULE_LICENSE("GPL");