1 // SPDX-License-Identifier: GPL-2.0+
2 //
3 //  Copyright (C) 2013, Analog Devices Inc.
4 //	Author: Lars-Peter Clausen <lars@metafoo.de>
5 
6 #include <linux/module.h>
7 #include <linux/init.h>
8 #include <linux/dmaengine.h>
9 #include <linux/slab.h>
10 #include <sound/pcm.h>
11 #include <sound/pcm_params.h>
12 #include <sound/soc.h>
13 #include <linux/dma-mapping.h>
14 #include <linux/of.h>
15 
16 #include <sound/dmaengine_pcm.h>
17 
18 static unsigned int prealloc_buffer_size_kbytes = 512;
19 module_param(prealloc_buffer_size_kbytes, uint, 0444);
20 MODULE_PARM_DESC(prealloc_buffer_size_kbytes, "Preallocate DMA buffer size (KB).");
21 
22 /*
23  * The platforms dmaengine driver does not support reporting the amount of
24  * bytes that are still left to transfer.
25  */
26 #define SND_DMAENGINE_PCM_FLAG_NO_RESIDUE BIT(31)
27 
28 static struct device *dmaengine_dma_dev(struct dmaengine_pcm *pcm,
29 	struct snd_pcm_substream *substream)
30 {
31 	if (!pcm->chan[substream->stream])
32 		return NULL;
33 
34 	return pcm->chan[substream->stream]->device->dev;
35 }
36 
37 /**
38  * snd_dmaengine_pcm_prepare_slave_config() - Generic prepare_slave_config callback
39  * @substream: PCM substream
40  * @params: hw_params
41  * @slave_config: DMA slave config to prepare
42  *
43  * This function can be used as a generic prepare_slave_config callback for
44  * platforms which make use of the snd_dmaengine_dai_dma_data struct for their
45  * DAI DMA data. Internally the function will first call
46  * snd_hwparams_to_dma_slave_config to fill in the slave config based on the
47  * hw_params, followed by snd_dmaengine_set_config_from_dai_data to fill in the
48  * remaining fields based on the DAI DMA data.
49  */
50 int snd_dmaengine_pcm_prepare_slave_config(struct snd_pcm_substream *substream,
51 	struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
52 {
53 	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
54 	struct snd_dmaengine_dai_dma_data *dma_data;
55 	int ret;
56 
57 	if (rtd->dai_link->num_cpus > 1) {
58 		dev_err(rtd->dev,
59 			"%s doesn't support Multi CPU yet\n", __func__);
60 		return -EINVAL;
61 	}
62 
63 	dma_data = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
64 
65 	ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
66 	if (ret)
67 		return ret;
68 
69 	snd_dmaengine_pcm_set_config_from_dai_data(substream, dma_data,
70 		slave_config);
71 
72 	return 0;
73 }
74 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_prepare_slave_config);
75 
76 static int dmaengine_pcm_hw_params(struct snd_soc_component *component,
77 				   struct snd_pcm_substream *substream,
78 				   struct snd_pcm_hw_params *params)
79 {
80 	struct dmaengine_pcm *pcm = soc_component_to_pcm(component);
81 	struct dma_chan *chan = snd_dmaengine_pcm_get_chan(substream);
82 	struct dma_slave_config slave_config;
83 	int ret;
84 
85 	if (!pcm->config->prepare_slave_config)
86 		return 0;
87 
88 	memset(&slave_config, 0, sizeof(slave_config));
89 
90 	ret = pcm->config->prepare_slave_config(substream, params, &slave_config);
91 	if (ret)
92 		return ret;
93 
94 	return dmaengine_slave_config(chan, &slave_config);
95 }
96 
97 static int
98 dmaengine_pcm_set_runtime_hwparams(struct snd_soc_component *component,
99 				   struct snd_pcm_substream *substream)
100 {
101 	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
102 	struct dmaengine_pcm *pcm = soc_component_to_pcm(component);
103 	struct device *dma_dev = dmaengine_dma_dev(pcm, substream);
104 	struct dma_chan *chan = pcm->chan[substream->stream];
105 	struct snd_dmaengine_dai_dma_data *dma_data;
106 	struct snd_pcm_hardware hw;
107 
108 	if (rtd->dai_link->num_cpus > 1) {
109 		dev_err(rtd->dev,
110 			"%s doesn't support Multi CPU yet\n", __func__);
111 		return -EINVAL;
112 	}
113 
114 	if (pcm->config->pcm_hardware)
115 		return snd_soc_set_runtime_hwparams(substream,
116 				pcm->config->pcm_hardware);
117 
118 	dma_data = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
119 
120 	memset(&hw, 0, sizeof(hw));
121 	hw.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
122 			SNDRV_PCM_INFO_INTERLEAVED;
123 	hw.periods_min = 2;
124 	hw.periods_max = UINT_MAX;
125 	hw.period_bytes_min = dma_data->maxburst * DMA_SLAVE_BUSWIDTH_8_BYTES;
126 	if (!hw.period_bytes_min)
127 		hw.period_bytes_min = 256;
128 	hw.period_bytes_max = dma_get_max_seg_size(dma_dev);
129 	hw.buffer_bytes_max = SIZE_MAX;
130 	hw.fifo_size = dma_data->fifo_size;
131 
132 	if (pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
133 		hw.info |= SNDRV_PCM_INFO_BATCH;
134 
135 	/**
136 	 * FIXME: Remove the return value check to align with the code
137 	 * before adding snd_dmaengine_pcm_refine_runtime_hwparams
138 	 * function.
139 	 */
140 	snd_dmaengine_pcm_refine_runtime_hwparams(substream,
141 						  dma_data,
142 						  &hw,
143 						  chan);
144 
145 	return snd_soc_set_runtime_hwparams(substream, &hw);
146 }
147 
148 static int dmaengine_pcm_open(struct snd_soc_component *component,
149 			      struct snd_pcm_substream *substream)
150 {
151 	struct dmaengine_pcm *pcm = soc_component_to_pcm(component);
152 	struct dma_chan *chan = pcm->chan[substream->stream];
153 	int ret;
154 
155 	ret = dmaengine_pcm_set_runtime_hwparams(component, substream);
156 	if (ret)
157 		return ret;
158 
159 	return snd_dmaengine_pcm_open(substream, chan);
160 }
161 
162 static int dmaengine_pcm_close(struct snd_soc_component *component,
163 			       struct snd_pcm_substream *substream)
164 {
165 	return snd_dmaengine_pcm_close(substream);
166 }
167 
168 static int dmaengine_pcm_trigger(struct snd_soc_component *component,
169 				 struct snd_pcm_substream *substream, int cmd)
170 {
171 	return snd_dmaengine_pcm_trigger(substream, cmd);
172 }
173 
174 static struct dma_chan *dmaengine_pcm_compat_request_channel(
175 	struct snd_soc_component *component,
176 	struct snd_soc_pcm_runtime *rtd,
177 	struct snd_pcm_substream *substream)
178 {
179 	struct dmaengine_pcm *pcm = soc_component_to_pcm(component);
180 	struct snd_dmaengine_dai_dma_data *dma_data;
181 
182 	if (rtd->dai_link->num_cpus > 1) {
183 		dev_err(rtd->dev,
184 			"%s doesn't support Multi CPU yet\n", __func__);
185 		return NULL;
186 	}
187 
188 	dma_data = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
189 
190 	if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) && pcm->chan[0])
191 		return pcm->chan[0];
192 
193 	if (pcm->config->compat_request_channel)
194 		return pcm->config->compat_request_channel(rtd, substream);
195 
196 	return snd_dmaengine_pcm_request_channel(pcm->config->compat_filter_fn,
197 						 dma_data->filter_data);
198 }
199 
200 static bool dmaengine_pcm_can_report_residue(struct device *dev,
201 	struct dma_chan *chan)
202 {
203 	struct dma_slave_caps dma_caps;
204 	int ret;
205 
206 	ret = dma_get_slave_caps(chan, &dma_caps);
207 	if (ret != 0) {
208 		dev_warn(dev, "Failed to get DMA channel capabilities, falling back to period counting: %d\n",
209 			 ret);
210 		return false;
211 	}
212 
213 	if (dma_caps.residue_granularity == DMA_RESIDUE_GRANULARITY_DESCRIPTOR)
214 		return false;
215 
216 	return true;
217 }
218 
219 static int dmaengine_pcm_new(struct snd_soc_component *component,
220 			     struct snd_soc_pcm_runtime *rtd)
221 {
222 	struct dmaengine_pcm *pcm = soc_component_to_pcm(component);
223 	const struct snd_dmaengine_pcm_config *config = pcm->config;
224 	struct device *dev = component->dev;
225 	size_t prealloc_buffer_size;
226 	size_t max_buffer_size;
227 	unsigned int i;
228 
229 	if (config->prealloc_buffer_size)
230 		prealloc_buffer_size = config->prealloc_buffer_size;
231 	else
232 		prealloc_buffer_size = prealloc_buffer_size_kbytes * 1024;
233 
234 	if (config->pcm_hardware && config->pcm_hardware->buffer_bytes_max)
235 		max_buffer_size = config->pcm_hardware->buffer_bytes_max;
236 	else
237 		max_buffer_size = SIZE_MAX;
238 
239 	for_each_pcm_streams(i) {
240 		struct snd_pcm_substream *substream = rtd->pcm->streams[i].substream;
241 		if (!substream)
242 			continue;
243 
244 		if (!pcm->chan[i] && config->chan_names[i])
245 			pcm->chan[i] = dma_request_slave_channel(dev,
246 				config->chan_names[i]);
247 
248 		if (!pcm->chan[i] && (pcm->flags & SND_DMAENGINE_PCM_FLAG_COMPAT)) {
249 			pcm->chan[i] = dmaengine_pcm_compat_request_channel(
250 				component, rtd, substream);
251 		}
252 
253 		if (!pcm->chan[i]) {
254 			dev_err(component->dev,
255 				"Missing dma channel for stream: %d\n", i);
256 			return -EINVAL;
257 		}
258 
259 		snd_pcm_set_managed_buffer(substream,
260 				SNDRV_DMA_TYPE_DEV_IRAM,
261 				dmaengine_dma_dev(pcm, substream),
262 				prealloc_buffer_size,
263 				max_buffer_size);
264 
265 		if (!dmaengine_pcm_can_report_residue(dev, pcm->chan[i]))
266 			pcm->flags |= SND_DMAENGINE_PCM_FLAG_NO_RESIDUE;
267 
268 		if (rtd->pcm->streams[i].pcm->name[0] == '\0') {
269 			strscpy_pad(rtd->pcm->streams[i].pcm->name,
270 				    rtd->pcm->streams[i].pcm->id,
271 				    sizeof(rtd->pcm->streams[i].pcm->name));
272 		}
273 	}
274 
275 	return 0;
276 }
277 
278 static snd_pcm_uframes_t dmaengine_pcm_pointer(
279 	struct snd_soc_component *component,
280 	struct snd_pcm_substream *substream)
281 {
282 	struct dmaengine_pcm *pcm = soc_component_to_pcm(component);
283 
284 	if (pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
285 		return snd_dmaengine_pcm_pointer_no_residue(substream);
286 	else
287 		return snd_dmaengine_pcm_pointer(substream);
288 }
289 
290 static int dmaengine_copy_user(struct snd_soc_component *component,
291 			       struct snd_pcm_substream *substream,
292 			       int channel, unsigned long hwoff,
293 			       void __user *buf, unsigned long bytes)
294 {
295 	struct snd_pcm_runtime *runtime = substream->runtime;
296 	struct dmaengine_pcm *pcm = soc_component_to_pcm(component);
297 	int (*process)(struct snd_pcm_substream *substream,
298 		       int channel, unsigned long hwoff,
299 		       void *buf, unsigned long bytes) = pcm->config->process;
300 	bool is_playback = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
301 	void *dma_ptr = runtime->dma_area + hwoff +
302 			channel * (runtime->dma_bytes / runtime->channels);
303 
304 	if (is_playback)
305 		if (copy_from_user(dma_ptr, buf, bytes))
306 			return -EFAULT;
307 
308 	if (process) {
309 		int ret = process(substream, channel, hwoff, (__force void *)buf, bytes);
310 		if (ret < 0)
311 			return ret;
312 	}
313 
314 	if (!is_playback)
315 		if (copy_to_user(buf, dma_ptr, bytes))
316 			return -EFAULT;
317 
318 	return 0;
319 }
320 
321 static const struct snd_soc_component_driver dmaengine_pcm_component = {
322 	.name		= SND_DMAENGINE_PCM_DRV_NAME,
323 	.probe_order	= SND_SOC_COMP_ORDER_LATE,
324 	.open		= dmaengine_pcm_open,
325 	.close		= dmaengine_pcm_close,
326 	.hw_params	= dmaengine_pcm_hw_params,
327 	.trigger	= dmaengine_pcm_trigger,
328 	.pointer	= dmaengine_pcm_pointer,
329 	.pcm_construct	= dmaengine_pcm_new,
330 };
331 
332 static const struct snd_soc_component_driver dmaengine_pcm_component_process = {
333 	.name		= SND_DMAENGINE_PCM_DRV_NAME,
334 	.probe_order	= SND_SOC_COMP_ORDER_LATE,
335 	.open		= dmaengine_pcm_open,
336 	.close		= dmaengine_pcm_close,
337 	.hw_params	= dmaengine_pcm_hw_params,
338 	.trigger	= dmaengine_pcm_trigger,
339 	.pointer	= dmaengine_pcm_pointer,
340 	.copy_user	= dmaengine_copy_user,
341 	.pcm_construct	= dmaengine_pcm_new,
342 };
343 
344 static const char * const dmaengine_pcm_dma_channel_names[] = {
345 	[SNDRV_PCM_STREAM_PLAYBACK] = "tx",
346 	[SNDRV_PCM_STREAM_CAPTURE] = "rx",
347 };
348 
349 static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
350 	struct device *dev, const struct snd_dmaengine_pcm_config *config)
351 {
352 	unsigned int i;
353 	const char *name;
354 	struct dma_chan *chan;
355 
356 	if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_DT) || (!dev->of_node &&
357 	    !(config->dma_dev && config->dma_dev->of_node)))
358 		return 0;
359 
360 	if (config->dma_dev) {
361 		/*
362 		 * If this warning is seen, it probably means that your Linux
363 		 * device structure does not match your HW device structure.
364 		 * It would be best to refactor the Linux device structure to
365 		 * correctly match the HW structure.
366 		 */
367 		dev_warn(dev, "DMA channels sourced from device %s",
368 			 dev_name(config->dma_dev));
369 		dev = config->dma_dev;
370 	}
371 
372 	for_each_pcm_streams(i) {
373 		if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
374 			name = "rx-tx";
375 		else
376 			name = dmaengine_pcm_dma_channel_names[i];
377 		if (config->chan_names[i])
378 			name = config->chan_names[i];
379 		chan = dma_request_chan(dev, name);
380 		if (IS_ERR(chan)) {
381 			/*
382 			 * Only report probe deferral errors, channels
383 			 * might not be present for devices that
384 			 * support only TX or only RX.
385 			 */
386 			if (PTR_ERR(chan) == -EPROBE_DEFER)
387 				return -EPROBE_DEFER;
388 			pcm->chan[i] = NULL;
389 		} else {
390 			pcm->chan[i] = chan;
391 		}
392 		if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
393 			break;
394 	}
395 
396 	if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
397 		pcm->chan[1] = pcm->chan[0];
398 
399 	return 0;
400 }
401 
402 static void dmaengine_pcm_release_chan(struct dmaengine_pcm *pcm)
403 {
404 	unsigned int i;
405 
406 	for_each_pcm_streams(i) {
407 		if (!pcm->chan[i])
408 			continue;
409 		dma_release_channel(pcm->chan[i]);
410 		if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
411 			break;
412 	}
413 }
414 
415 static const struct snd_dmaengine_pcm_config snd_dmaengine_pcm_default_config = {
416 	.prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
417 };
418 
419 /**
420  * snd_dmaengine_pcm_register - Register a dmaengine based PCM device
421  * @dev: The parent device for the PCM device
422  * @config: Platform specific PCM configuration
423  * @flags: Platform specific quirks
424  */
425 int snd_dmaengine_pcm_register(struct device *dev,
426 	const struct snd_dmaengine_pcm_config *config, unsigned int flags)
427 {
428 	const struct snd_soc_component_driver *driver;
429 	struct dmaengine_pcm *pcm;
430 	int ret;
431 
432 	pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
433 	if (!pcm)
434 		return -ENOMEM;
435 
436 #ifdef CONFIG_DEBUG_FS
437 	pcm->component.debugfs_prefix = "dma";
438 #endif
439 	if (!config)
440 		config = &snd_dmaengine_pcm_default_config;
441 	pcm->config = config;
442 	pcm->flags = flags;
443 
444 	ret = dmaengine_pcm_request_chan_of(pcm, dev, config);
445 	if (ret)
446 		goto err_free_dma;
447 
448 	if (config->process)
449 		driver = &dmaengine_pcm_component_process;
450 	else
451 		driver = &dmaengine_pcm_component;
452 
453 	ret = snd_soc_component_initialize(&pcm->component, driver, dev);
454 	if (ret)
455 		goto err_free_dma;
456 
457 	ret = snd_soc_add_component(&pcm->component, NULL, 0);
458 	if (ret)
459 		goto err_free_dma;
460 
461 	return 0;
462 
463 err_free_dma:
464 	dmaengine_pcm_release_chan(pcm);
465 	kfree(pcm);
466 	return ret;
467 }
468 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_register);
469 
470 /**
471  * snd_dmaengine_pcm_unregister - Removes a dmaengine based PCM device
472  * @dev: Parent device the PCM was register with
473  *
474  * Removes a dmaengine based PCM device previously registered with
475  * snd_dmaengine_pcm_register.
476  */
477 void snd_dmaengine_pcm_unregister(struct device *dev)
478 {
479 	struct snd_soc_component *component;
480 	struct dmaengine_pcm *pcm;
481 
482 	component = snd_soc_lookup_component(dev, SND_DMAENGINE_PCM_DRV_NAME);
483 	if (!component)
484 		return;
485 
486 	pcm = soc_component_to_pcm(component);
487 
488 	snd_soc_unregister_component_by_driver(dev, component->driver);
489 	dmaengine_pcm_release_chan(pcm);
490 	kfree(pcm);
491 }
492 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_unregister);
493 
494 MODULE_LICENSE("GPL");
495