1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * atmel-pcm-dma.c  --  ALSA PCM DMA support for the Atmel SoC.
4  *
5  *  Copyright (C) 2012 Atmel
6  *
7  * Author: Bo Shen <voice.shen@atmel.com>
8  *
9  * Based on atmel-pcm by:
10  * Sedji Gaouaou <sedji.gaouaou@atmel.com>
11  * Copyright 2008 Atmel
12  */
13 
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 
22 #include <sound/core.h>
23 #include <sound/pcm.h>
24 #include <sound/pcm_params.h>
25 #include <sound/soc.h>
26 #include <sound/dmaengine_pcm.h>
27 
28 #include "atmel-pcm.h"
29 
30 /*--------------------------------------------------------------------------*\
31  * Hardware definition
32 \*--------------------------------------------------------------------------*/
33 static const struct snd_pcm_hardware atmel_pcm_dma_hardware = {
34 	.info			= SNDRV_PCM_INFO_MMAP |
35 				  SNDRV_PCM_INFO_MMAP_VALID |
36 				  SNDRV_PCM_INFO_INTERLEAVED |
37 				  SNDRV_PCM_INFO_RESUME |
38 				  SNDRV_PCM_INFO_PAUSE,
39 	.period_bytes_min	= 256,		/* lighting DMA overhead */
40 	.period_bytes_max	= 2 * 0xffff,	/* if 2 bytes format */
41 	.periods_min		= 8,
42 	.periods_max		= 1024,		/* no limit */
43 	.buffer_bytes_max	= 512 * 1024,
44 };
45 
46 /*
47  * atmel_pcm_dma_irq: SSC interrupt handler for DMAENGINE enabled SSC
48  *
49  * We use DMAENGINE to send/receive data to/from SSC so this ISR is only to
50  * check if any overrun occured.
51  */
atmel_pcm_dma_irq(u32 ssc_sr,struct snd_pcm_substream * substream)52 static void atmel_pcm_dma_irq(u32 ssc_sr,
53 	struct snd_pcm_substream *substream)
54 {
55 	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
56 	struct atmel_pcm_dma_params *prtd;
57 
58 	prtd = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
59 
60 	if (ssc_sr & prtd->mask->ssc_error) {
61 		if (snd_pcm_running(substream))
62 			pr_warn("atmel-pcm: buffer %s on %s (SSC_SR=%#x)\n",
63 				substream->stream == SNDRV_PCM_STREAM_PLAYBACK
64 				? "underrun" : "overrun", prtd->name,
65 				ssc_sr);
66 
67 		/* stop RX and capture: will be enabled again at restart */
68 		ssc_writex(prtd->ssc->regs, SSC_CR, prtd->mask->ssc_disable);
69 		snd_pcm_stop_xrun(substream);
70 
71 		/* now drain RHR and read status to remove xrun condition */
72 		ssc_readx(prtd->ssc->regs, SSC_RHR);
73 		ssc_readx(prtd->ssc->regs, SSC_SR);
74 	}
75 }
76 
atmel_pcm_configure_dma(struct snd_pcm_substream * substream,struct snd_pcm_hw_params * params,struct dma_slave_config * slave_config)77 static int atmel_pcm_configure_dma(struct snd_pcm_substream *substream,
78 	struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
79 {
80 	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
81 	struct atmel_pcm_dma_params *prtd;
82 	struct ssc_device *ssc;
83 	int ret;
84 
85 	prtd = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
86 	ssc = prtd->ssc;
87 
88 	ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
89 	if (ret) {
90 		pr_err("atmel-pcm: hwparams to dma slave configure failed\n");
91 		return ret;
92 	}
93 
94 	slave_config->dst_addr = ssc->phybase + SSC_THR;
95 	slave_config->dst_maxburst = 1;
96 
97 	slave_config->src_addr = ssc->phybase + SSC_RHR;
98 	slave_config->src_maxburst = 1;
99 
100 	prtd->dma_intr_handler = atmel_pcm_dma_irq;
101 
102 	return 0;
103 }
104 
105 static const struct snd_dmaengine_pcm_config atmel_dmaengine_pcm_config = {
106 	.prepare_slave_config = atmel_pcm_configure_dma,
107 	.pcm_hardware = &atmel_pcm_dma_hardware,
108 	.prealloc_buffer_size = 64 * 1024,
109 };
110 
atmel_pcm_dma_platform_register(struct device * dev)111 int atmel_pcm_dma_platform_register(struct device *dev)
112 {
113 	return devm_snd_dmaengine_pcm_register(dev,
114 					&atmel_dmaengine_pcm_config, 0);
115 }
116 EXPORT_SYMBOL(atmel_pcm_dma_platform_register);
117 
118 MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>");
119 MODULE_DESCRIPTION("Atmel DMA based PCM module");
120 MODULE_LICENSE("GPL");
121