xref: /openbmc/linux/sound/core/pcm_memory.c (revision 21bb8af5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Digital Audio (PCM) abstract layer
4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5  */
6 
7 #include <linux/io.h>
8 #include <linux/time.h>
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/moduleparam.h>
12 #include <linux/vmalloc.h>
13 #include <linux/export.h>
14 #include <sound/core.h>
15 #include <sound/pcm.h>
16 #include <sound/info.h>
17 #include <sound/initval.h>
18 #include "pcm_local.h"
19 
20 static int preallocate_dma = 1;
21 module_param(preallocate_dma, int, 0444);
22 MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
23 
24 static int maximum_substreams = 4;
25 module_param(maximum_substreams, int, 0444);
26 MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
27 
28 static const size_t snd_minimum_buffer = 16384;
29 
30 static unsigned long max_alloc_per_card = 32UL * 1024UL * 1024UL;
31 module_param(max_alloc_per_card, ulong, 0644);
32 MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card.");
33 
34 static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
35 			  int str, size_t size, struct snd_dma_buffer *dmab)
36 {
37 	enum dma_data_direction dir;
38 	int err;
39 
40 	if (max_alloc_per_card &&
41 	    card->total_pcm_alloc_bytes + size > max_alloc_per_card)
42 		return -ENOMEM;
43 
44 	if (str == SNDRV_PCM_STREAM_PLAYBACK)
45 		dir = DMA_TO_DEVICE;
46 	else
47 		dir = DMA_FROM_DEVICE;
48 	err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab);
49 	if (!err) {
50 		mutex_lock(&card->memory_mutex);
51 		card->total_pcm_alloc_bytes += dmab->bytes;
52 		mutex_unlock(&card->memory_mutex);
53 	}
54 	return err;
55 }
56 
57 static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
58 {
59 	if (!dmab->area)
60 		return;
61 	mutex_lock(&card->memory_mutex);
62 	WARN_ON(card->total_pcm_alloc_bytes < dmab->bytes);
63 	card->total_pcm_alloc_bytes -= dmab->bytes;
64 	mutex_unlock(&card->memory_mutex);
65 	snd_dma_free_pages(dmab);
66 	dmab->area = NULL;
67 }
68 
69 /*
70  * try to allocate as the large pages as possible.
71  * stores the resultant memory size in *res_size.
72  *
73  * the minimum size is snd_minimum_buffer.  it should be power of 2.
74  */
75 static int preallocate_pcm_pages(struct snd_pcm_substream *substream,
76 				 size_t size, bool no_fallback)
77 {
78 	struct snd_dma_buffer *dmab = &substream->dma_buffer;
79 	struct snd_card *card = substream->pcm->card;
80 	size_t orig_size = size;
81 	int err;
82 
83 	do {
84 		err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
85 				     substream->stream, size, dmab);
86 		if (err != -ENOMEM)
87 			return err;
88 		if (no_fallback)
89 			break;
90 		size >>= 1;
91 	} while (size >= snd_minimum_buffer);
92 	dmab->bytes = 0; /* tell error */
93 	pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
94 		substream->pcm->card->number, substream->pcm->device,
95 		substream->stream ? 'c' : 'p', substream->number,
96 		substream->pcm->name, orig_size);
97 	return -ENOMEM;
98 }
99 
100 /**
101  * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
102  * @substream: the pcm substream instance
103  *
104  * Releases the pre-allocated buffer of the given substream.
105  */
106 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
107 {
108 	do_free_pages(substream->pcm->card, &substream->dma_buffer);
109 }
110 
111 /**
112  * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
113  * @pcm: the pcm instance
114  *
115  * Releases all the pre-allocated buffers on the given pcm.
116  */
117 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
118 {
119 	struct snd_pcm_substream *substream;
120 	int stream;
121 
122 	for_each_pcm_substream(pcm, stream, substream)
123 		snd_pcm_lib_preallocate_free(substream);
124 }
125 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
126 
127 #ifdef CONFIG_SND_VERBOSE_PROCFS
128 /*
129  * read callback for prealloc proc file
130  *
131  * prints the current allocated size in kB.
132  */
133 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
134 					      struct snd_info_buffer *buffer)
135 {
136 	struct snd_pcm_substream *substream = entry->private_data;
137 	snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
138 }
139 
140 /*
141  * read callback for prealloc_max proc file
142  *
143  * prints the maximum allowed size in kB.
144  */
145 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
146 						  struct snd_info_buffer *buffer)
147 {
148 	struct snd_pcm_substream *substream = entry->private_data;
149 	snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
150 }
151 
152 /*
153  * write callback for prealloc proc file
154  *
155  * accepts the preallocation size in kB.
156  */
157 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
158 					       struct snd_info_buffer *buffer)
159 {
160 	struct snd_pcm_substream *substream = entry->private_data;
161 	struct snd_card *card = substream->pcm->card;
162 	char line[64], str[64];
163 	size_t size;
164 	struct snd_dma_buffer new_dmab;
165 
166 	mutex_lock(&substream->pcm->open_mutex);
167 	if (substream->runtime) {
168 		buffer->error = -EBUSY;
169 		goto unlock;
170 	}
171 	if (!snd_info_get_line(buffer, line, sizeof(line))) {
172 		snd_info_get_str(str, line, sizeof(str));
173 		size = simple_strtoul(str, NULL, 10) * 1024;
174 		if ((size != 0 && size < 8192) || size > substream->dma_max) {
175 			buffer->error = -EINVAL;
176 			goto unlock;
177 		}
178 		if (substream->dma_buffer.bytes == size)
179 			goto unlock;
180 		memset(&new_dmab, 0, sizeof(new_dmab));
181 		new_dmab.dev = substream->dma_buffer.dev;
182 		if (size > 0) {
183 			if (do_alloc_pages(card,
184 					   substream->dma_buffer.dev.type,
185 					   substream->dma_buffer.dev.dev,
186 					   substream->stream,
187 					   size, &new_dmab) < 0) {
188 				buffer->error = -ENOMEM;
189 				pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
190 					 substream->pcm->card->number, substream->pcm->device,
191 					 substream->stream ? 'c' : 'p', substream->number,
192 					 substream->pcm->name, size);
193 				goto unlock;
194 			}
195 			substream->buffer_bytes_max = size;
196 		} else {
197 			substream->buffer_bytes_max = UINT_MAX;
198 		}
199 		if (substream->dma_buffer.area)
200 			do_free_pages(card, &substream->dma_buffer);
201 		substream->dma_buffer = new_dmab;
202 	} else {
203 		buffer->error = -EINVAL;
204 	}
205  unlock:
206 	mutex_unlock(&substream->pcm->open_mutex);
207 }
208 
209 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
210 {
211 	struct snd_info_entry *entry;
212 
213 	entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
214 					   substream->proc_root);
215 	if (entry) {
216 		snd_info_set_text_ops(entry, substream,
217 				      snd_pcm_lib_preallocate_proc_read);
218 		entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
219 		entry->mode |= 0200;
220 	}
221 	entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
222 					   substream->proc_root);
223 	if (entry)
224 		snd_info_set_text_ops(entry, substream,
225 				      snd_pcm_lib_preallocate_max_proc_read);
226 }
227 
228 #else /* !CONFIG_SND_VERBOSE_PROCFS */
229 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
230 {
231 }
232 #endif /* CONFIG_SND_VERBOSE_PROCFS */
233 
234 /*
235  * pre-allocate the buffer and create a proc file for the substream
236  */
237 static int preallocate_pages(struct snd_pcm_substream *substream,
238 			      int type, struct device *data,
239 			      size_t size, size_t max, bool managed)
240 {
241 	int err;
242 
243 	if (snd_BUG_ON(substream->dma_buffer.dev.type))
244 		return -EINVAL;
245 
246 	substream->dma_buffer.dev.type = type;
247 	substream->dma_buffer.dev.dev = data;
248 
249 	if (size > 0) {
250 		if (!max) {
251 			/* no fallback, only also inform -ENOMEM */
252 			err = preallocate_pcm_pages(substream, size, true);
253 			if (err < 0)
254 				return err;
255 		} else if (preallocate_dma &&
256 			   substream->number < maximum_substreams) {
257 			err = preallocate_pcm_pages(substream, size, false);
258 			if (err < 0 && err != -ENOMEM)
259 				return err;
260 		}
261 	}
262 
263 	if (substream->dma_buffer.bytes > 0)
264 		substream->buffer_bytes_max = substream->dma_buffer.bytes;
265 	substream->dma_max = max;
266 	if (max > 0)
267 		preallocate_info_init(substream);
268 	if (managed)
269 		substream->managed_buffer_alloc = 1;
270 	return 0;
271 }
272 
273 static int preallocate_pages_for_all(struct snd_pcm *pcm, int type,
274 				      void *data, size_t size, size_t max,
275 				      bool managed)
276 {
277 	struct snd_pcm_substream *substream;
278 	int stream, err;
279 
280 	for_each_pcm_substream(pcm, stream, substream) {
281 		err = preallocate_pages(substream, type, data, size, max, managed);
282 		if (err < 0)
283 			return err;
284 	}
285 	return 0;
286 }
287 
288 /**
289  * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
290  * @substream: the pcm substream instance
291  * @type: DMA type (SNDRV_DMA_TYPE_*)
292  * @data: DMA type dependent data
293  * @size: the requested pre-allocation size in bytes
294  * @max: the max. allowed pre-allocation size
295  *
296  * Do pre-allocation for the given DMA buffer type.
297  */
298 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
299 				  int type, struct device *data,
300 				  size_t size, size_t max)
301 {
302 	preallocate_pages(substream, type, data, size, max, false);
303 }
304 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
305 
306 /**
307  * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
308  * @pcm: the pcm instance
309  * @type: DMA type (SNDRV_DMA_TYPE_*)
310  * @data: DMA type dependent data
311  * @size: the requested pre-allocation size in bytes
312  * @max: the max. allowed pre-allocation size
313  *
314  * Do pre-allocation to all substreams of the given pcm for the
315  * specified DMA type.
316  */
317 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
318 					  int type, void *data,
319 					  size_t size, size_t max)
320 {
321 	preallocate_pages_for_all(pcm, type, data, size, max, false);
322 }
323 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
324 
325 /**
326  * snd_pcm_set_managed_buffer - set up buffer management for a substream
327  * @substream: the pcm substream instance
328  * @type: DMA type (SNDRV_DMA_TYPE_*)
329  * @data: DMA type dependent data
330  * @size: the requested pre-allocation size in bytes
331  * @max: the max. allowed pre-allocation size
332  *
333  * Do pre-allocation for the given DMA buffer type, and set the managed
334  * buffer allocation mode to the given substream.
335  * In this mode, PCM core will allocate a buffer automatically before PCM
336  * hw_params ops call, and release the buffer after PCM hw_free ops call
337  * as well, so that the driver doesn't need to invoke the allocation and
338  * the release explicitly in its callback.
339  * When a buffer is actually allocated before the PCM hw_params call, it
340  * turns on the runtime buffer_changed flag for drivers changing their h/w
341  * parameters accordingly.
342  *
343  * When @size is non-zero and @max is zero, this tries to allocate for only
344  * the exact buffer size without fallback, and may return -ENOMEM.
345  * Otherwise, the function tries to allocate smaller chunks if the allocation
346  * fails.  This is the behavior of snd_pcm_set_fixed_buffer().
347  *
348  * When both @size and @max are zero, the function only sets up the buffer
349  * for later dynamic allocations. It's used typically for buffers with
350  * SNDRV_DMA_TYPE_VMALLOC type.
351  *
352  * Upon successful buffer allocation and setup, the function returns 0.
353  */
354 int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
355 				struct device *data, size_t size, size_t max)
356 {
357 	return preallocate_pages(substream, type, data, size, max, true);
358 }
359 EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
360 
361 /**
362  * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
363  *	for all substreams
364  * @pcm: the pcm instance
365  * @type: DMA type (SNDRV_DMA_TYPE_*)
366  * @data: DMA type dependent data
367  * @size: the requested pre-allocation size in bytes
368  * @max: the max. allowed pre-allocation size
369  *
370  * Do pre-allocation to all substreams of the given pcm for the specified DMA
371  * type and size, and set the managed_buffer_alloc flag to each substream.
372  */
373 int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
374 				   struct device *data,
375 				   size_t size, size_t max)
376 {
377 	return preallocate_pages_for_all(pcm, type, data, size, max, true);
378 }
379 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
380 
381 /**
382  * snd_pcm_lib_malloc_pages - allocate the DMA buffer
383  * @substream: the substream to allocate the DMA buffer to
384  * @size: the requested buffer size in bytes
385  *
386  * Allocates the DMA buffer on the BUS type given earlier to
387  * snd_pcm_lib_preallocate_xxx_pages().
388  *
389  * Return: 1 if the buffer is changed, 0 if not changed, or a negative
390  * code on failure.
391  */
392 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
393 {
394 	struct snd_card *card;
395 	struct snd_pcm_runtime *runtime;
396 	struct snd_dma_buffer *dmab = NULL;
397 
398 	if (PCM_RUNTIME_CHECK(substream))
399 		return -EINVAL;
400 	if (snd_BUG_ON(substream->dma_buffer.dev.type ==
401 		       SNDRV_DMA_TYPE_UNKNOWN))
402 		return -EINVAL;
403 	runtime = substream->runtime;
404 	card = substream->pcm->card;
405 
406 	if (runtime->dma_buffer_p) {
407 		/* perphaps, we might free the large DMA memory region
408 		   to save some space here, but the actual solution
409 		   costs us less time */
410 		if (runtime->dma_buffer_p->bytes >= size) {
411 			runtime->dma_bytes = size;
412 			return 0;	/* ok, do not change */
413 		}
414 		snd_pcm_lib_free_pages(substream);
415 	}
416 	if (substream->dma_buffer.area != NULL &&
417 	    substream->dma_buffer.bytes >= size) {
418 		dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
419 	} else {
420 		/* dma_max=0 means the fixed size preallocation */
421 		if (substream->dma_buffer.area && !substream->dma_max)
422 			return -ENOMEM;
423 		dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
424 		if (! dmab)
425 			return -ENOMEM;
426 		dmab->dev = substream->dma_buffer.dev;
427 		if (do_alloc_pages(card,
428 				   substream->dma_buffer.dev.type,
429 				   substream->dma_buffer.dev.dev,
430 				   substream->stream,
431 				   size, dmab) < 0) {
432 			kfree(dmab);
433 			pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
434 				 substream->pcm->card->number, substream->pcm->device,
435 				 substream->stream ? 'c' : 'p', substream->number,
436 				 substream->pcm->name, size);
437 			return -ENOMEM;
438 		}
439 	}
440 	snd_pcm_set_runtime_buffer(substream, dmab);
441 	runtime->dma_bytes = size;
442 	return 1;			/* area was changed */
443 }
444 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
445 
446 /**
447  * snd_pcm_lib_free_pages - release the allocated DMA buffer.
448  * @substream: the substream to release the DMA buffer
449  *
450  * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
451  *
452  * Return: Zero if successful, or a negative error code on failure.
453  */
454 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
455 {
456 	struct snd_pcm_runtime *runtime;
457 
458 	if (PCM_RUNTIME_CHECK(substream))
459 		return -EINVAL;
460 	runtime = substream->runtime;
461 	if (runtime->dma_area == NULL)
462 		return 0;
463 	if (runtime->dma_buffer_p != &substream->dma_buffer) {
464 		struct snd_card *card = substream->pcm->card;
465 
466 		/* it's a newly allocated buffer.  release it now. */
467 		do_free_pages(card, runtime->dma_buffer_p);
468 		kfree(runtime->dma_buffer_p);
469 	}
470 	snd_pcm_set_runtime_buffer(substream, NULL);
471 	return 0;
472 }
473 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
474 
475 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
476 				      size_t size, gfp_t gfp_flags)
477 {
478 	struct snd_pcm_runtime *runtime;
479 
480 	if (PCM_RUNTIME_CHECK(substream))
481 		return -EINVAL;
482 	runtime = substream->runtime;
483 	if (runtime->dma_area) {
484 		if (runtime->dma_bytes >= size)
485 			return 0; /* already large enough */
486 		vfree(runtime->dma_area);
487 	}
488 	runtime->dma_area = __vmalloc(size, gfp_flags);
489 	if (!runtime->dma_area)
490 		return -ENOMEM;
491 	runtime->dma_bytes = size;
492 	return 1;
493 }
494 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
495 
496 /**
497  * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
498  * @substream: the substream with a buffer allocated by
499  *	snd_pcm_lib_alloc_vmalloc_buffer()
500  *
501  * Return: Zero if successful, or a negative error code on failure.
502  */
503 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
504 {
505 	struct snd_pcm_runtime *runtime;
506 
507 	if (PCM_RUNTIME_CHECK(substream))
508 		return -EINVAL;
509 	runtime = substream->runtime;
510 	vfree(runtime->dma_area);
511 	runtime->dma_area = NULL;
512 	return 0;
513 }
514 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
515 
516 /**
517  * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
518  * @substream: the substream with a buffer allocated by
519  *	snd_pcm_lib_alloc_vmalloc_buffer()
520  * @offset: offset in the buffer
521  *
522  * This function is to be used as the page callback in the PCM ops.
523  *
524  * Return: The page struct, or %NULL on failure.
525  */
526 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
527 					  unsigned long offset)
528 {
529 	return vmalloc_to_page(substream->runtime->dma_area + offset);
530 }
531 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);
532