soc/atmel/atmel-pcm-dma.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * atmel-pcm-dma.c  --  ALSA PCM DMA support for the Atmel SoC.
0004  *
0005  *  Copyright (C) 2012 Atmel
0006  *
0007  * Author: Bo Shen <voice.shen@atmel.com>
0008  *
0009  * Based on atmel-pcm by:
0010  * Sedji Gaouaou <sedji.gaouaou@atmel.com>
0011  * Copyright 2008 Atmel
0012  */
0013
0014 #include <linux/module.h>
0015 #include <linux/init.h>
0016 #include <linux/platform_device.h>
0017 #include <linux/slab.h>
0018 #include <linux/dma-mapping.h>
0019 #include <linux/dmaengine.h>
0020 #include <linux/atmel-ssc.h>
0021
0022 #include <sound/core.h>
0023 #include <sound/pcm.h>
0024 #include <sound/pcm_params.h>
0025 #include <sound/soc.h>
0026 #include <sound/dmaengine_pcm.h>
0027
0028 #include "atmel-pcm.h"
0029
0030 /*--------------------------------------------------------------------------*\
0031  * Hardware definition
0032 \*--------------------------------------------------------------------------*/
0033 static const struct snd_pcm_hardware atmel_pcm_dma_hardware = {
0034     .info           = SNDRV_PCM_INFO_MMAP |
0035                   SNDRV_PCM_INFO_MMAP_VALID |
0036                   SNDRV_PCM_INFO_INTERLEAVED |
0037                   SNDRV_PCM_INFO_RESUME |
0038                   SNDRV_PCM_INFO_PAUSE,
0039     .period_bytes_min   = 256,      /* lighting DMA overhead */
0040     .period_bytes_max   = 2 * 0xffff,   /* if 2 bytes format */
0041     .periods_min        = 8,
0042     .periods_max        = 1024,     /* no limit */
0043     .buffer_bytes_max   = 512 * 1024,
0044 };
0045
0046 /*
0047  * atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
0048  *
0049  * We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
0050  * check if any overrun occured.
0051  */
0052 static void atmel_pcm_dma_irq(u32 ssc_sr,
0053     struct snd_pcm_substream *substream)
0054 {
0055     struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
0056     struct atmel_pcm_dma_params *prtd;
0057
0058     prtd = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
0059
0060     if (ssc_sr & prtd->mask->ssc_error) {
0061         if (snd_pcm_running(substream))
0062             pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",
0063                 substream->stream == SNDRV_PCM_STREAM_PLAYBACK
0064                 ? "underrun" : "overrun", prtd->name,
0065                 ssc_sr);
0066
0067         /* stop RX and capture: will be enabled again at restart */
0068         ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);
0069         snd_pcm_stop_xrun(substream);
0070
0071         /* now drain RHR and read status to remove xrun condition */
0072         ssc_readx(prtd->ssc->regs, SSC_RHR);
0073         ssc_readx(prtd->ssc->regs, SSC_SR);
0074     }
0075 }
0076
0077 static int atmel_pcm_configure_dma(struct snd_pcm_substream *substream,
0078     struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
0079 {
0080     struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
0081     struct atmel_pcm_dma_params *prtd;
0082     struct ssc_device *ssc;
0083     int ret;
0084
0085     prtd = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
0086     ssc = prtd->ssc;
0087
0088     ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
0089     if (ret) {
0090         pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
0091         return ret;
0092     }
0093
0094     slave_config->dst_addr = ssc->phybase + SSC_THR;
0095     slave_config->dst_maxburst = 1;
0096
0097     slave_config->src_addr = ssc->phybase + SSC_RHR;
0098     slave_config->src_maxburst = 1;
0099
0100     prtd->dma_intr_handler = atmel_pcm_dma_irq;
0101
0102     return 0;
0103 }
0104
0105 static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {
0106     .prepare_slave_config = atmel_pcm_configure_dma,
0107     .pcm_hardware = &atmel_pcm_dma_hardware,
0108     .prealloc_buffer_size = 64 * 1024,
0109 };
0110
0111 int atmel_pcm_dma_platform_register(struct device *dev)
0112 {
0113     return devm_snd_dmaengine_pcm_register(dev,
0114                     &atmel_dmaengine_pcm_config, 0);
0115 }
0116 EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
0117
0118 MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
0119 MODULE_DESCRIPTION("Atmel DMA based PCM module");
0120 MODULE_LICENSE("GPL");