1 /*
2  *  Copyright (C) 2013, Analog Devices Inc.
3  *	Author: Lars-Peter Clausen <lars@metafoo.de>
4  *
5  *  This program is free software; you can redistribute it and/or modify it
6  *  under  the terms of the GNU General  Public License as published by the
7  *  Free Software Foundation;  either version 2 of the License, or (at your
8  *  option) any later version.
9  *
10  *  You should have received a copy of the GNU General Public License along
11  *  with this program; if not, write to the Free Software Foundation, Inc.,
12  *  675 Mass Ave, Cambridge, MA 02139, USA.
13  *
14  */
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/dmaengine.h>
18 #include <linux/slab.h>
19 #include <sound/pcm.h>
20 #include <sound/pcm_params.h>
21 #include <sound/soc.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/of.h>
24 
25 #include <sound/dmaengine_pcm.h>
26 
27 struct dmaengine_pcm {
28 	struct dma_chan *chan[SNDRV_PCM_STREAM_CAPTURE + 1];
29 	const struct snd_dmaengine_pcm_config *config;
30 	struct snd_soc_platform platform;
31 	unsigned int flags;
32 };
33 
34 static struct dmaengine_pcm *soc_platform_to_pcm(struct snd_soc_platform *p)
35 {
36 	return container_of(p, struct dmaengine_pcm, platform);
37 }
38 
39 /**
40  * snd_dmaengine_pcm_prepare_slave_config() - Generic prepare_slave_config callback
41  * @substream: PCM substream
42  * @params: hw_params
43  * @slave_config: DMA slave config to prepare
44  *
45  * This function can be used as a generic prepare_slave_config callback for
46  * platforms which make use of the snd_dmaengine_dai_dma_data struct for their
47  * DAI DMA data. Internally the function will first call
48  * snd_hwparams_to_dma_slave_config to fill in the slave config based on the
49  * hw_params, followed by snd_dmaengine_set_config_from_dai_data to fill in the
50  * remaining fields based on the DAI DMA data.
51  */
52 int snd_dmaengine_pcm_prepare_slave_config(struct snd_pcm_substream *substream,
53 	struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
54 {
55 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
56 	struct snd_dmaengine_dai_dma_data *dma_data;
57 	int ret;
58 
59 	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
60 
61 	ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
62 	if (ret)
63 		return ret;
64 
65 	snd_dmaengine_pcm_set_config_from_dai_data(substream, dma_data,
66 		slave_config);
67 
68 	return 0;
69 }
70 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_prepare_slave_config);
71 
72 static int dmaengine_pcm_hw_params(struct snd_pcm_substream *substream,
73 	struct snd_pcm_hw_params *params)
74 {
75 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
76 	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
77 	struct dma_chan *chan = snd_dmaengine_pcm_get_chan(substream);
78 	struct dma_slave_config slave_config;
79 	int ret;
80 
81 	if (pcm->config->prepare_slave_config) {
82 		ret = pcm->config->prepare_slave_config(substream, params,
83 				&slave_config);
84 		if (ret)
85 			return ret;
86 
87 		ret = dmaengine_slave_config(chan, &slave_config);
88 		if (ret)
89 			return ret;
90 	}
91 
92 	return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
93 }
94 
95 static int dmaengine_pcm_open(struct snd_pcm_substream *substream)
96 {
97 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
98 	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
99 	struct dma_chan *chan = pcm->chan[substream->stream];
100 	int ret;
101 
102 	ret = snd_soc_set_runtime_hwparams(substream,
103 				pcm->config->pcm_hardware);
104 	if (ret)
105 		return ret;
106 
107 	return snd_dmaengine_pcm_open(substream, chan);
108 }
109 
110 static struct device *dmaengine_dma_dev(struct dmaengine_pcm *pcm,
111 	struct snd_pcm_substream *substream)
112 {
113 	if (!pcm->chan[substream->stream])
114 		return NULL;
115 
116 	return pcm->chan[substream->stream]->device->dev;
117 }
118 
119 static void dmaengine_pcm_free(struct snd_pcm *pcm)
120 {
121 	snd_pcm_lib_preallocate_free_for_all(pcm);
122 }
123 
124 static struct dma_chan *dmaengine_pcm_compat_request_channel(
125 	struct snd_soc_pcm_runtime *rtd,
126 	struct snd_pcm_substream *substream)
127 {
128 	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
129 
130 	if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) && pcm->chan[0])
131 		return pcm->chan[0];
132 
133 	if (pcm->config->compat_request_channel)
134 		return pcm->config->compat_request_channel(rtd, substream);
135 
136 	return snd_dmaengine_pcm_request_channel(pcm->config->compat_filter_fn,
137 		snd_soc_dai_get_dma_data(rtd->cpu_dai, substream));
138 }
139 
140 static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
141 {
142 	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
143 	const struct snd_dmaengine_pcm_config *config = pcm->config;
144 	struct snd_pcm_substream *substream;
145 	unsigned int i;
146 	int ret;
147 
148 	for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
149 		substream = rtd->pcm->streams[i].substream;
150 		if (!substream)
151 			continue;
152 
153 		if (!pcm->chan[i] && (pcm->flags & SND_DMAENGINE_PCM_FLAG_COMPAT)) {
154 			pcm->chan[i] = dmaengine_pcm_compat_request_channel(rtd,
155 				substream);
156 		}
157 
158 		if (!pcm->chan[i]) {
159 			dev_err(rtd->platform->dev,
160 				"Missing dma channel for stream: %d\n", i);
161 			ret = -EINVAL;
162 			goto err_free;
163 		}
164 
165 		ret = snd_pcm_lib_preallocate_pages(substream,
166 				SNDRV_DMA_TYPE_DEV,
167 				dmaengine_dma_dev(pcm, substream),
168 				config->prealloc_buffer_size,
169 				config->pcm_hardware->buffer_bytes_max);
170 		if (ret)
171 			goto err_free;
172 	}
173 
174 	return 0;
175 
176 err_free:
177 	dmaengine_pcm_free(rtd->pcm);
178 	return ret;
179 }
180 
181 static const struct snd_pcm_ops dmaengine_pcm_ops = {
182 	.open		= dmaengine_pcm_open,
183 	.close		= snd_dmaengine_pcm_close,
184 	.ioctl		= snd_pcm_lib_ioctl,
185 	.hw_params	= dmaengine_pcm_hw_params,
186 	.hw_free	= snd_pcm_lib_free_pages,
187 	.trigger	= snd_dmaengine_pcm_trigger,
188 	.pointer	= snd_dmaengine_pcm_pointer,
189 };
190 
191 static const struct snd_soc_platform_driver dmaengine_pcm_platform = {
192 	.ops		= &dmaengine_pcm_ops,
193 	.pcm_new	= dmaengine_pcm_new,
194 	.pcm_free	= dmaengine_pcm_free,
195 	.probe_order	= SND_SOC_COMP_ORDER_LATE,
196 };
197 
198 static const struct snd_pcm_ops dmaengine_no_residue_pcm_ops = {
199 	.open		= dmaengine_pcm_open,
200 	.close		= snd_dmaengine_pcm_close,
201 	.ioctl		= snd_pcm_lib_ioctl,
202 	.hw_params	= dmaengine_pcm_hw_params,
203 	.hw_free	= snd_pcm_lib_free_pages,
204 	.trigger	= snd_dmaengine_pcm_trigger,
205 	.pointer	= snd_dmaengine_pcm_pointer_no_residue,
206 };
207 
208 static const struct snd_soc_platform_driver dmaengine_no_residue_pcm_platform = {
209 	.ops		= &dmaengine_no_residue_pcm_ops,
210 	.pcm_new	= dmaengine_pcm_new,
211 	.pcm_free	= dmaengine_pcm_free,
212 	.probe_order	= SND_SOC_COMP_ORDER_LATE,
213 };
214 
215 static const char * const dmaengine_pcm_dma_channel_names[] = {
216 	[SNDRV_PCM_STREAM_PLAYBACK] = "tx",
217 	[SNDRV_PCM_STREAM_CAPTURE] = "rx",
218 };
219 
220 static void dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
221 	struct device *dev)
222 {
223 	unsigned int i;
224 
225 	if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_DT) || !dev->of_node)
226 		return;
227 
228 	if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) {
229 		pcm->chan[0] = dma_request_slave_channel(dev, "rx-tx");
230 		pcm->chan[1] = pcm->chan[0];
231 	} else {
232 		for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
233 			pcm->chan[i] = dma_request_slave_channel(dev,
234 					dmaengine_pcm_dma_channel_names[i]);
235 		}
236 	}
237 }
238 
239 /**
240  * snd_dmaengine_pcm_register - Register a dmaengine based PCM device
241  * @dev: The parent device for the PCM device
242  * @config: Platform specific PCM configuration
243  * @flags: Platform specific quirks
244  */
245 int snd_dmaengine_pcm_register(struct device *dev,
246 	const struct snd_dmaengine_pcm_config *config, unsigned int flags)
247 {
248 	struct dmaengine_pcm *pcm;
249 
250 	pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
251 	if (!pcm)
252 		return -ENOMEM;
253 
254 	pcm->config = config;
255 	pcm->flags = flags;
256 
257 	dmaengine_pcm_request_chan_of(pcm, dev);
258 
259 	if (flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
260 		return snd_soc_add_platform(dev, &pcm->platform,
261 				&dmaengine_no_residue_pcm_platform);
262 	else
263 		return snd_soc_add_platform(dev, &pcm->platform,
264 				&dmaengine_pcm_platform);
265 }
266 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_register);
267 
268 /**
269  * snd_dmaengine_pcm_unregister - Removes a dmaengine based PCM device
270  * @dev: Parent device the PCM was register with
271  *
272  * Removes a dmaengine based PCM device previously registered with
273  * snd_dmaengine_pcm_register.
274  */
275 void snd_dmaengine_pcm_unregister(struct device *dev)
276 {
277 	struct snd_soc_platform *platform;
278 	struct dmaengine_pcm *pcm;
279 	unsigned int i;
280 
281 	platform = snd_soc_lookup_platform(dev);
282 	if (!platform)
283 		return;
284 
285 	pcm = soc_platform_to_pcm(platform);
286 
287 	for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
288 		if (pcm->chan[i]) {
289 			dma_release_channel(pcm->chan[i]);
290 			if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
291 				break;
292 		}
293 	}
294 
295 	snd_soc_remove_platform(platform);
296 	kfree(pcm);
297 }
298 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_unregister);
299 
300 MODULE_LICENSE("GPL");
301