1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * atmel-pcm-dma.c -- ALSA PCM DMA support for the Atmel SoC.
5 * Copyright (C) 2012 Atmel
7 * Author: Bo Shen <voice.shen@atmel.com>
9 * Based on atmel-pcm by:
10 * Sedji Gaouaou <sedji.gaouaou@atmel.com>
11 * Copyright 2008 Atmel
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>
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>
29 #include "atmel-pcm.h"
31 /*--------------------------------------------------------------------------*\
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 |
40 .period_bytes_min = 256, /* lighting DMA overhead */
41 .period_bytes_max = 2 * 0xffff, /* if 2 bytes format */
43 .periods_max = 1024, /* no limit */
44 .buffer_bytes_max = 512 * 1024,
48 * atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
50 * We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
51 * check if any overrun occured.
53 static void atmel_pcm_dma_irq(u32 ssc_sr,
54 struct snd_pcm_substream *substream)
56 struct snd_soc_pcm_runtime *rtd = substream->private_data;
57 struct atmel_pcm_dma_params *prtd;
59 prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
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,
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);
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);
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)
81 struct snd_soc_pcm_runtime *rtd = substream->private_data;
82 struct atmel_pcm_dma_params *prtd;
83 struct ssc_device *ssc;
86 prtd = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
89 ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
91 pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
95 slave_config->dst_addr = ssc->phybase + SSC_THR;
96 slave_config->dst_maxburst = 1;
98 slave_config->src_addr = ssc->phybase + SSC_RHR;
99 slave_config->src_maxburst = 1;
101 prtd->dma_intr_handler = atmel_pcm_dma_irq;
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,
112 int atmel_pcm_dma_platform_register(struct device *dev)
114 return devm_snd_dmaengine_pcm_register(dev,
115 &atmel_dmaengine_pcm_config, 0);
117 EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
119 MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
120 MODULE_DESCRIPTION("Atmel DMA based PCM module");
121 MODULE_LICENSE("GPL");