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 | */ |
52 | static void atmel_pcm_dma_irq(u32 ssc_sr, |
53 | struct snd_pcm_substream *substream) |
54 | { |
55 | struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream); |
56 | struct atmel_pcm_dma_params *prtd; |
57 | |
58 | prtd = snd_soc_dai_get_dma_data(snd_soc_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 | |
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 = snd_soc_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(snd_soc_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 | |
111 | int atmel_pcm_dma_platform_register(struct device *dev) |
112 | { |
113 | return devm_snd_dmaengine_pcm_register(dev, |
114 | config: &atmel_dmaengine_pcm_config, flags: 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 | |