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\*--------------------------------------------------------------------------*/
47static 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 */
66static 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
91static 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
119static 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
125int atmel_pcm_dma_platform_register(struct device *dev)
126{
127	return snd_dmaengine_pcm_register(dev, &atmel_dmaengine_pcm_config,
128			SND_DMAENGINE_PCM_FLAG_NO_RESIDUE);
129}
130EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
131
132void atmel_pcm_dma_platform_unregister(struct device *dev)
133{
134	snd_dmaengine_pcm_unregister(dev);
135}
136EXPORT_SYMBOL(atmel_pcm_dma_platform_unregister);
137
138MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
139MODULE_DESCRIPTION("Atmel DMA based PCM module");
140MODULE_LICENSE("GPL");
141