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         .formats                = SNDRV_PCM_FMTBIT_S16_LE,
  54         .period_bytes_min       = 256,          /* lighting DMA overhead */
  55         .period_bytes_max       = 2 * 0xffff,   /* if 2 bytes format */
  56         .periods_min            = 8,
  57         .periods_max            = 1024,         /* no limit */
  58         .buffer_bytes_max       = ATMEL_SSC_DMABUF_SIZE,
  59 };
  60
  61 /**
  62  * atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
  63  *
  64  * We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
  65  * check if any overrun occured.
  66  */
  67 static void atmel_pcm_dma_irq(u32 ssc_sr,
  68         struct snd_pcm_substream *substream)
  69 {
  70         struct snd_soc_pcm_runtime *rtd = substream->private_data;
  71         struct atmel_pcm_dma_params *prtd;
  72
  73         prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
  74
  75         if (ssc_sr & prtd->mask->ssc_error) {
  76                 if (snd_pcm_running(substream))
  77                         pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",
  78                                 substream->stream == SNDRV_PCM_STREAM_PLAYBACK
  79                                 ? "underrun" : "overrun", prtd->name,
  80                                 ssc_sr);
  81
  82                 /* stop RX and capture: will be enabled again at restart */
  83                 ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);
  84                 snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
  85
  86                 /* now drain RHR and read status to remove xrun condition */
  87                 ssc_readx(prtd->ssc->regs, SSC_RHR);
  88                 ssc_readx(prtd->ssc->regs, SSC_SR);
  89         }
  90 }
  91
  92 static int atmel_pcm_configure_dma(struct snd_pcm_substream *substream,
  93         struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
  94 {
  95         struct snd_soc_pcm_runtime *rtd = substream->private_data;
  96         struct atmel_pcm_dma_params *prtd;
  97         struct ssc_device *ssc;
  98         int ret;
  99
 100         prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
 101         ssc = prtd->ssc;
 102
 103         ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
 104         if (ret) {
 105                 pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
 106                 return ret;
 107         }
 108
 109         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 110                 slave_config->dst_addr = ssc->phybase + SSC_THR;
 111                 slave_config->dst_maxburst = 1;
 112         } else {
 113                 slave_config->src_addr = ssc->phybase + SSC_RHR;
 114                 slave_config->src_maxburst = 1;
 115         }
 116
 117         prtd->dma_intr_handler = atmel_pcm_dma_irq;
 118
 119         return 0;
 120 }
 121
 122 static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {
 123         .prepare_slave_config = atmel_pcm_configure_dma,
 124         .pcm_hardware = &atmel_pcm_dma_hardware,
 125         .prealloc_buffer_size = ATMEL_SSC_DMABUF_SIZE,
 126 };
 127
 128 int atmel_pcm_dma_platform_register(struct device *dev)
 129 {
 130         return snd_dmaengine_pcm_register(dev, &atmel_dmaengine_pcm_config,
 131                         SND_DMAENGINE_PCM_FLAG_NO_RESIDUE);
 132 }
 133 EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
 134
 135 void atmel_pcm_dma_platform_unregister(struct device *dev)
 136 {
 137         snd_dmaengine_pcm_unregister(dev);
 138 }
 139 EXPORT_SYMBOL(atmel_pcm_dma_platform_unregister);
 140
 141 MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
 142 MODULE_DESCRIPTION("Atmel DMA based PCM module");
 143 MODULE_LICENSE("GPL");