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"); 140