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
27struct dmaengine_pcm {
28	struct dma_chan *chan[SNDRV_PCM_STREAM_LAST + 1];
29	const struct snd_dmaengine_pcm_config *config;
30	struct snd_soc_platform platform;
31	unsigned int flags;
32};
33
34static struct dmaengine_pcm *soc_platform_to_pcm(struct snd_soc_platform *p)
35{
36	return container_of(p, struct dmaengine_pcm, platform);
37}
38
39static struct device *dmaengine_dma_dev(struct dmaengine_pcm *pcm,
40	struct snd_pcm_substream *substream)
41{
42	if (!pcm->chan[substream->stream])
43		return NULL;
44
45	return pcm->chan[substream->stream]->device->dev;
46}
47
48/**
49 * snd_dmaengine_pcm_prepare_slave_config() - Generic prepare_slave_config callback
50 * @substream: PCM substream
51 * @params: hw_params
52 * @slave_config: DMA slave config to prepare
53 *
54 * This function can be used as a generic prepare_slave_config callback for
55 * platforms which make use of the snd_dmaengine_dai_dma_data struct for their
56 * DAI DMA data. Internally the function will first call
57 * snd_hwparams_to_dma_slave_config to fill in the slave config based on the
58 * hw_params, followed by snd_dmaengine_set_config_from_dai_data to fill in the
59 * remaining fields based on the DAI DMA data.
60 */
61int snd_dmaengine_pcm_prepare_slave_config(struct snd_pcm_substream *substream,
62	struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
63{
64	struct snd_soc_pcm_runtime *rtd = substream->private_data;
65	struct snd_dmaengine_dai_dma_data *dma_data;
66	int ret;
67
68	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
69
70	ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
71	if (ret)
72		return ret;
73
74	snd_dmaengine_pcm_set_config_from_dai_data(substream, dma_data,
75		slave_config);
76
77	return 0;
78}
79EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_prepare_slave_config);
80
81static int dmaengine_pcm_hw_params(struct snd_pcm_substream *substream,
82	struct snd_pcm_hw_params *params)
83{
84	struct snd_soc_pcm_runtime *rtd = substream->private_data;
85	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
86	struct dma_chan *chan = snd_dmaengine_pcm_get_chan(substream);
87	int (*prepare_slave_config)(struct snd_pcm_substream *substream,
88			struct snd_pcm_hw_params *params,
89			struct dma_slave_config *slave_config);
90	struct dma_slave_config slave_config;
91	int ret;
92
93	memset(&slave_config, 0, sizeof(slave_config));
94
95	if (!pcm->config)
96		prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config;
97	else
98		prepare_slave_config = pcm->config->prepare_slave_config;
99
100	if (prepare_slave_config) {
101		ret = prepare_slave_config(substream, params, &slave_config);
102		if (ret)
103			return ret;
104
105		ret = dmaengine_slave_config(chan, &slave_config);
106		if (ret)
107			return ret;
108	}
109
110	return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
111}
112
113static int dmaengine_pcm_set_runtime_hwparams(struct snd_pcm_substream *substream)
114{
115	struct snd_soc_pcm_runtime *rtd = substream->private_data;
116	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
117	struct device *dma_dev = dmaengine_dma_dev(pcm, substream);
118	struct dma_chan *chan = pcm->chan[substream->stream];
119	struct snd_dmaengine_dai_dma_data *dma_data;
120	struct dma_slave_caps dma_caps;
121	struct snd_pcm_hardware hw;
122	u32 addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
123			  BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
124			  BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
125	int i, ret;
126
127	if (pcm->config && pcm->config->pcm_hardware)
128		return snd_soc_set_runtime_hwparams(substream,
129				pcm->config->pcm_hardware);
130
131	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
132
133	memset(&hw, 0, sizeof(hw));
134	hw.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
135			SNDRV_PCM_INFO_INTERLEAVED;
136	hw.periods_min = 2;
137	hw.periods_max = UINT_MAX;
138	hw.period_bytes_min = 256;
139	hw.period_bytes_max = dma_get_max_seg_size(dma_dev);
140	hw.buffer_bytes_max = SIZE_MAX;
141	hw.fifo_size = dma_data->fifo_size;
142
143	if (pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
144		hw.info |= SNDRV_PCM_INFO_BATCH;
145
146	ret = dma_get_slave_caps(chan, &dma_caps);
147	if (ret == 0) {
148		if (dma_caps.cmd_pause)
149			hw.info |= SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME;
150		if (dma_caps.residue_granularity <= DMA_RESIDUE_GRANULARITY_SEGMENT)
151			hw.info |= SNDRV_PCM_INFO_BATCH;
152
153		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
154			addr_widths = dma_caps.dst_addr_widths;
155		else
156			addr_widths = dma_caps.src_addr_widths;
157	}
158
159	/*
160	 * Prepare formats mask for valid/allowed sample types. If the dma does
161	 * not have support for the given physical word size, it needs to be
162	 * masked out so user space can not use the format which produces
163	 * corrupted audio.
164	 * In case the dma driver does not implement the slave_caps the default
165	 * assumption is that it supports 1, 2 and 4 bytes widths.
166	 */
167	for (i = 0; i <= SNDRV_PCM_FORMAT_LAST; i++) {
168		int bits = snd_pcm_format_physical_width(i);
169
170		/* Enable only samples with DMA supported physical widths */
171		switch (bits) {
172		case 8:
173		case 16:
174		case 24:
175		case 32:
176		case 64:
177			if (addr_widths & (1 << (bits / 8)))
178				hw.formats |= (1LL << i);
179			break;
180		default:
181			/* Unsupported types */
182			break;
183		}
184	}
185
186	return snd_soc_set_runtime_hwparams(substream, &hw);
187}
188
189static int dmaengine_pcm_open(struct snd_pcm_substream *substream)
190{
191	struct snd_soc_pcm_runtime *rtd = substream->private_data;
192	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
193	struct dma_chan *chan = pcm->chan[substream->stream];
194	int ret;
195
196	ret = dmaengine_pcm_set_runtime_hwparams(substream);
197	if (ret)
198		return ret;
199
200	return snd_dmaengine_pcm_open(substream, chan);
201}
202
203static struct dma_chan *dmaengine_pcm_compat_request_channel(
204	struct snd_soc_pcm_runtime *rtd,
205	struct snd_pcm_substream *substream)
206{
207	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
208	struct snd_dmaengine_dai_dma_data *dma_data;
209	dma_filter_fn fn = NULL;
210
211	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
212
213	if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) && pcm->chan[0])
214		return pcm->chan[0];
215
216	if (pcm->config && pcm->config->compat_request_channel)
217		return pcm->config->compat_request_channel(rtd, substream);
218
219	if (pcm->config)
220		fn = pcm->config->compat_filter_fn;
221
222	return snd_dmaengine_pcm_request_channel(fn, dma_data->filter_data);
223}
224
225static bool dmaengine_pcm_can_report_residue(struct dma_chan *chan)
226{
227	struct dma_slave_caps dma_caps;
228	int ret;
229
230	ret = dma_get_slave_caps(chan, &dma_caps);
231	if (ret != 0)
232		return true;
233
234	if (dma_caps.residue_granularity == DMA_RESIDUE_GRANULARITY_DESCRIPTOR)
235		return false;
236
237	return true;
238}
239
240static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
241{
242	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
243	const struct snd_dmaengine_pcm_config *config = pcm->config;
244	struct device *dev = rtd->platform->dev;
245	struct snd_dmaengine_dai_dma_data *dma_data;
246	struct snd_pcm_substream *substream;
247	size_t prealloc_buffer_size;
248	size_t max_buffer_size;
249	unsigned int i;
250	int ret;
251
252	if (config && config->prealloc_buffer_size) {
253		prealloc_buffer_size = config->prealloc_buffer_size;
254		max_buffer_size = config->pcm_hardware->buffer_bytes_max;
255	} else {
256		prealloc_buffer_size = 512 * 1024;
257		max_buffer_size = SIZE_MAX;
258	}
259
260
261	for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
262		substream = rtd->pcm->streams[i].substream;
263		if (!substream)
264			continue;
265
266		dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
267
268		if (!pcm->chan[i] &&
269		    (pcm->flags & SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME))
270			pcm->chan[i] = dma_request_slave_channel(dev,
271				dma_data->chan_name);
272
273		if (!pcm->chan[i] && (pcm->flags & SND_DMAENGINE_PCM_FLAG_COMPAT)) {
274			pcm->chan[i] = dmaengine_pcm_compat_request_channel(rtd,
275				substream);
276		}
277
278		if (!pcm->chan[i]) {
279			dev_err(rtd->platform->dev,
280				"Missing dma channel for stream: %d\n", i);
281			return -EINVAL;
282		}
283
284		ret = snd_pcm_lib_preallocate_pages(substream,
285				SNDRV_DMA_TYPE_DEV_IRAM,
286				dmaengine_dma_dev(pcm, substream),
287				prealloc_buffer_size,
288				max_buffer_size);
289		if (ret)
290			return ret;
291
292		/*
293		 * This will only return false if we know for sure that at least
294		 * one channel does not support residue reporting. If the DMA
295		 * driver does not implement the slave_caps API we rely having
296		 * the NO_RESIDUE flag set manually in case residue reporting is
297		 * not supported.
298		 */
299		if (!dmaengine_pcm_can_report_residue(pcm->chan[i]))
300			pcm->flags |= SND_DMAENGINE_PCM_FLAG_NO_RESIDUE;
301	}
302
303	return 0;
304}
305
306static snd_pcm_uframes_t dmaengine_pcm_pointer(
307	struct snd_pcm_substream *substream)
308{
309	struct snd_soc_pcm_runtime *rtd = substream->private_data;
310	struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
311
312	if (pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
313		return snd_dmaengine_pcm_pointer_no_residue(substream);
314	else
315		return snd_dmaengine_pcm_pointer(substream);
316}
317
318static const struct snd_pcm_ops dmaengine_pcm_ops = {
319	.open		= dmaengine_pcm_open,
320	.close		= snd_dmaengine_pcm_close,
321	.ioctl		= snd_pcm_lib_ioctl,
322	.hw_params	= dmaengine_pcm_hw_params,
323	.hw_free	= snd_pcm_lib_free_pages,
324	.trigger	= snd_dmaengine_pcm_trigger,
325	.pointer	= dmaengine_pcm_pointer,
326};
327
328static const struct snd_soc_platform_driver dmaengine_pcm_platform = {
329	.component_driver = {
330		.probe_order = SND_SOC_COMP_ORDER_LATE,
331	},
332	.ops		= &dmaengine_pcm_ops,
333	.pcm_new	= dmaengine_pcm_new,
334};
335
336static const char * const dmaengine_pcm_dma_channel_names[] = {
337	[SNDRV_PCM_STREAM_PLAYBACK] = "tx",
338	[SNDRV_PCM_STREAM_CAPTURE] = "rx",
339};
340
341static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
342	struct device *dev, const struct snd_dmaengine_pcm_config *config)
343{
344	unsigned int i;
345	const char *name;
346	struct dma_chan *chan;
347
348	if ((pcm->flags & (SND_DMAENGINE_PCM_FLAG_NO_DT |
349			   SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME)) ||
350	    !dev->of_node)
351		return 0;
352
353	if (config && config->dma_dev) {
354		/*
355		 * If this warning is seen, it probably means that your Linux
356		 * device structure does not match your HW device structure.
357		 * It would be best to refactor the Linux device structure to
358		 * correctly match the HW structure.
359		 */
360		dev_warn(dev, "DMA channels sourced from device %s",
361			 dev_name(config->dma_dev));
362		dev = config->dma_dev;
363	}
364
365	for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE;
366	     i++) {
367		if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
368			name = "rx-tx";
369		else
370			name = dmaengine_pcm_dma_channel_names[i];
371		if (config && config->chan_names[i])
372			name = config->chan_names[i];
373		chan = dma_request_slave_channel_reason(dev, name);
374		if (IS_ERR(chan)) {
375			if (PTR_ERR(chan) == -EPROBE_DEFER)
376				return -EPROBE_DEFER;
377			pcm->chan[i] = NULL;
378		} else {
379			pcm->chan[i] = chan;
380		}
381		if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
382			break;
383	}
384
385	if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
386		pcm->chan[1] = pcm->chan[0];
387
388	return 0;
389}
390
391static void dmaengine_pcm_release_chan(struct dmaengine_pcm *pcm)
392{
393	unsigned int i;
394
395	for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE;
396	     i++) {
397		if (!pcm->chan[i])
398			continue;
399		dma_release_channel(pcm->chan[i]);
400		if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
401			break;
402	}
403}
404
405/**
406 * snd_dmaengine_pcm_register - Register a dmaengine based PCM device
407 * @dev: The parent device for the PCM device
408 * @config: Platform specific PCM configuration
409 * @flags: Platform specific quirks
410 */
411int snd_dmaengine_pcm_register(struct device *dev,
412	const struct snd_dmaengine_pcm_config *config, unsigned int flags)
413{
414	struct dmaengine_pcm *pcm;
415	int ret;
416
417	pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
418	if (!pcm)
419		return -ENOMEM;
420
421	pcm->config = config;
422	pcm->flags = flags;
423
424	ret = dmaengine_pcm_request_chan_of(pcm, dev, config);
425	if (ret)
426		goto err_free_dma;
427
428	ret = snd_soc_add_platform(dev, &pcm->platform,
429		&dmaengine_pcm_platform);
430	if (ret)
431		goto err_free_dma;
432
433	return 0;
434
435err_free_dma:
436	dmaengine_pcm_release_chan(pcm);
437	kfree(pcm);
438	return ret;
439}
440EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_register);
441
442/**
443 * snd_dmaengine_pcm_unregister - Removes a dmaengine based PCM device
444 * @dev: Parent device the PCM was register with
445 *
446 * Removes a dmaengine based PCM device previously registered with
447 * snd_dmaengine_pcm_register.
448 */
449void snd_dmaengine_pcm_unregister(struct device *dev)
450{
451	struct snd_soc_platform *platform;
452	struct dmaengine_pcm *pcm;
453
454	platform = snd_soc_lookup_platform(dev);
455	if (!platform)
456		return;
457
458	pcm = soc_platform_to_pcm(platform);
459
460	snd_soc_remove_platform(platform);
461	dmaengine_pcm_release_chan(pcm);
462	kfree(pcm);
463}
464EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_unregister);
465
466MODULE_LICENSE("GPL");
467