1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Digital Audio (PCM) abstract layer
4 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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"
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.");
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.");
28 static const size_t snd_minimum_buffer = 16384;
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.");
34 static void __update_allocated_size(struct snd_card *card, ssize_t bytes)
36 card->total_pcm_alloc_bytes += bytes;
39 static void update_allocated_size(struct snd_card *card, ssize_t bytes)
41 guard(mutex)(&card->memory_mutex);
42 __update_allocated_size(card, bytes);
45 static void decrease_allocated_size(struct snd_card *card, size_t bytes)
47 guard(mutex)(&card->memory_mutex);
48 WARN_ON(card->total_pcm_alloc_bytes < bytes);
49 __update_allocated_size(card, -(ssize_t)bytes);
52 static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
53 int str, size_t size, struct snd_dma_buffer *dmab)
55 enum dma_data_direction dir;
58 /* check and reserve the requested size */
59 scoped_guard(mutex, &card->memory_mutex) {
60 if (max_alloc_per_card &&
61 card->total_pcm_alloc_bytes + size > max_alloc_per_card)
63 __update_allocated_size(card, size);
66 if (str == SNDRV_PCM_STREAM_PLAYBACK)
69 dir = DMA_FROM_DEVICE;
70 err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab);
72 /* the actual allocation size might be bigger than requested,
73 * and we need to correct the account
75 if (dmab->bytes != size)
76 update_allocated_size(card, dmab->bytes - size);
78 /* take back on allocation failure */
79 decrease_allocated_size(card, size);
84 static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
88 decrease_allocated_size(card, dmab->bytes);
89 snd_dma_free_pages(dmab);
94 * try to allocate as the large pages as possible.
95 * stores the resultant memory size in *res_size.
97 * the minimum size is snd_minimum_buffer. it should be power of 2.
99 static int preallocate_pcm_pages(struct snd_pcm_substream *substream,
100 size_t size, bool no_fallback)
102 struct snd_dma_buffer *dmab = &substream->dma_buffer;
103 struct snd_card *card = substream->pcm->card;
104 size_t orig_size = size;
108 err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
109 substream->stream, size, dmab);
115 } while (size >= snd_minimum_buffer);
116 dmab->bytes = 0; /* tell error */
117 pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
118 substream->pcm->card->number, substream->pcm->device,
119 substream->stream ? 'c' : 'p', substream->number,
120 substream->pcm->name, orig_size);
125 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
126 * @substream: the pcm substream instance
128 * Releases the pre-allocated buffer of the given substream.
130 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
132 do_free_pages(substream->pcm->card, &substream->dma_buffer);
136 * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
137 * @pcm: the pcm instance
139 * Releases all the pre-allocated buffers on the given pcm.
141 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
143 struct snd_pcm_substream *substream;
146 for_each_pcm_substream(pcm, stream, substream)
147 snd_pcm_lib_preallocate_free(substream);
149 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
151 #ifdef CONFIG_SND_VERBOSE_PROCFS
153 * read callback for prealloc proc file
155 * prints the current allocated size in kB.
157 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
158 struct snd_info_buffer *buffer)
160 struct snd_pcm_substream *substream = entry->private_data;
161 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
165 * read callback for prealloc_max proc file
167 * prints the maximum allowed size in kB.
169 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
170 struct snd_info_buffer *buffer)
172 struct snd_pcm_substream *substream = entry->private_data;
173 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
177 * write callback for prealloc proc file
179 * accepts the preallocation size in kB.
181 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
182 struct snd_info_buffer *buffer)
184 struct snd_pcm_substream *substream = entry->private_data;
185 struct snd_card *card = substream->pcm->card;
186 char line[64], str[64];
188 struct snd_dma_buffer new_dmab;
190 guard(mutex)(&substream->pcm->open_mutex);
191 if (substream->runtime) {
192 buffer->error = -EBUSY;
195 if (!snd_info_get_line(buffer, line, sizeof(line))) {
196 snd_info_get_str(str, line, sizeof(str));
197 size = simple_strtoul(str, NULL, 10) * 1024;
198 if ((size != 0 && size < 8192) || size > substream->dma_max) {
199 buffer->error = -EINVAL;
202 if (substream->dma_buffer.bytes == size)
204 memset(&new_dmab, 0, sizeof(new_dmab));
205 new_dmab.dev = substream->dma_buffer.dev;
207 if (do_alloc_pages(card,
208 substream->dma_buffer.dev.type,
209 substream->dma_buffer.dev.dev,
211 size, &new_dmab) < 0) {
212 buffer->error = -ENOMEM;
213 pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
214 substream->pcm->card->number, substream->pcm->device,
215 substream->stream ? 'c' : 'p', substream->number,
216 substream->pcm->name, size);
219 substream->buffer_bytes_max = size;
221 substream->buffer_bytes_max = UINT_MAX;
223 if (substream->dma_buffer.area)
224 do_free_pages(card, &substream->dma_buffer);
225 substream->dma_buffer = new_dmab;
227 buffer->error = -EINVAL;
231 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
233 struct snd_info_entry *entry;
235 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
236 substream->proc_root);
238 snd_info_set_text_ops(entry, substream,
239 snd_pcm_lib_preallocate_proc_read);
240 entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
243 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
244 substream->proc_root);
246 snd_info_set_text_ops(entry, substream,
247 snd_pcm_lib_preallocate_max_proc_read);
250 #else /* !CONFIG_SND_VERBOSE_PROCFS */
251 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
254 #endif /* CONFIG_SND_VERBOSE_PROCFS */
257 * pre-allocate the buffer and create a proc file for the substream
259 static int preallocate_pages(struct snd_pcm_substream *substream,
260 int type, struct device *data,
261 size_t size, size_t max, bool managed)
265 if (snd_BUG_ON(substream->dma_buffer.dev.type))
268 substream->dma_buffer.dev.type = type;
269 substream->dma_buffer.dev.dev = data;
273 /* no fallback, only also inform -ENOMEM */
274 err = preallocate_pcm_pages(substream, size, true);
277 } else if (preallocate_dma &&
278 substream->number < maximum_substreams) {
279 err = preallocate_pcm_pages(substream, size, false);
280 if (err < 0 && err != -ENOMEM)
285 if (substream->dma_buffer.bytes > 0)
286 substream->buffer_bytes_max = substream->dma_buffer.bytes;
287 substream->dma_max = max;
289 preallocate_info_init(substream);
291 substream->managed_buffer_alloc = 1;
295 static int preallocate_pages_for_all(struct snd_pcm *pcm, int type,
296 void *data, size_t size, size_t max,
299 struct snd_pcm_substream *substream;
302 for_each_pcm_substream(pcm, stream, substream) {
303 err = preallocate_pages(substream, type, data, size, max, managed);
311 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
312 * @substream: the pcm substream instance
313 * @type: DMA type (SNDRV_DMA_TYPE_*)
314 * @data: DMA type dependent data
315 * @size: the requested pre-allocation size in bytes
316 * @max: the max. allowed pre-allocation size
318 * Do pre-allocation for the given DMA buffer type.
320 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
321 int type, struct device *data,
322 size_t size, size_t max)
324 preallocate_pages(substream, type, data, size, max, false);
326 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
329 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
330 * @pcm: the pcm instance
331 * @type: DMA type (SNDRV_DMA_TYPE_*)
332 * @data: DMA type dependent data
333 * @size: the requested pre-allocation size in bytes
334 * @max: the max. allowed pre-allocation size
336 * Do pre-allocation to all substreams of the given pcm for the
337 * specified DMA type.
339 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
340 int type, void *data,
341 size_t size, size_t max)
343 preallocate_pages_for_all(pcm, type, data, size, max, false);
345 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
348 * snd_pcm_set_managed_buffer - set up buffer management for a substream
349 * @substream: the pcm substream instance
350 * @type: DMA type (SNDRV_DMA_TYPE_*)
351 * @data: DMA type dependent data
352 * @size: the requested pre-allocation size in bytes
353 * @max: the max. allowed pre-allocation size
355 * Do pre-allocation for the given DMA buffer type, and set the managed
356 * buffer allocation mode to the given substream.
357 * In this mode, PCM core will allocate a buffer automatically before PCM
358 * hw_params ops call, and release the buffer after PCM hw_free ops call
359 * as well, so that the driver doesn't need to invoke the allocation and
360 * the release explicitly in its callback.
361 * When a buffer is actually allocated before the PCM hw_params call, it
362 * turns on the runtime buffer_changed flag for drivers changing their h/w
363 * parameters accordingly.
365 * When @size is non-zero and @max is zero, this tries to allocate for only
366 * the exact buffer size without fallback, and may return -ENOMEM.
367 * Otherwise, the function tries to allocate smaller chunks if the allocation
368 * fails. This is the behavior of snd_pcm_set_fixed_buffer().
370 * When both @size and @max are zero, the function only sets up the buffer
371 * for later dynamic allocations. It's used typically for buffers with
372 * SNDRV_DMA_TYPE_VMALLOC type.
374 * Upon successful buffer allocation and setup, the function returns 0.
376 * Return: zero if successful, or a negative error code
378 int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
379 struct device *data, size_t size, size_t max)
381 return preallocate_pages(substream, type, data, size, max, true);
383 EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
386 * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
388 * @pcm: the pcm instance
389 * @type: DMA type (SNDRV_DMA_TYPE_*)
390 * @data: DMA type dependent data
391 * @size: the requested pre-allocation size in bytes
392 * @max: the max. allowed pre-allocation size
394 * Do pre-allocation to all substreams of the given pcm for the specified DMA
395 * type and size, and set the managed_buffer_alloc flag to each substream.
397 * Return: zero if successful, or a negative error code
399 int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
401 size_t size, size_t max)
403 return preallocate_pages_for_all(pcm, type, data, size, max, true);
405 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
408 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
409 * @substream: the substream to allocate the DMA buffer to
410 * @size: the requested buffer size in bytes
412 * Allocates the DMA buffer on the BUS type given earlier to
413 * snd_pcm_lib_preallocate_xxx_pages().
415 * Return: 1 if the buffer is changed, 0 if not changed, or a negative
418 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
420 struct snd_card *card;
421 struct snd_pcm_runtime *runtime;
422 struct snd_dma_buffer *dmab = NULL;
424 if (PCM_RUNTIME_CHECK(substream))
426 if (snd_BUG_ON(substream->dma_buffer.dev.type ==
427 SNDRV_DMA_TYPE_UNKNOWN))
429 runtime = substream->runtime;
430 card = substream->pcm->card;
432 if (runtime->dma_buffer_p) {
433 /* perphaps, we might free the large DMA memory region
434 to save some space here, but the actual solution
435 costs us less time */
436 if (runtime->dma_buffer_p->bytes >= size) {
437 runtime->dma_bytes = size;
438 return 0; /* ok, do not change */
440 snd_pcm_lib_free_pages(substream);
442 if (substream->dma_buffer.area != NULL &&
443 substream->dma_buffer.bytes >= size) {
444 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
446 /* dma_max=0 means the fixed size preallocation */
447 if (substream->dma_buffer.area && !substream->dma_max)
449 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
452 dmab->dev = substream->dma_buffer.dev;
453 if (do_alloc_pages(card,
454 substream->dma_buffer.dev.type,
455 substream->dma_buffer.dev.dev,
459 pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
460 substream->pcm->card->number, substream->pcm->device,
461 substream->stream ? 'c' : 'p', substream->number,
462 substream->pcm->name, size);
466 snd_pcm_set_runtime_buffer(substream, dmab);
467 runtime->dma_bytes = size;
468 return 1; /* area was changed */
470 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
473 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
474 * @substream: the substream to release the DMA buffer
476 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
478 * Return: Zero if successful, or a negative error code on failure.
480 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
482 struct snd_pcm_runtime *runtime;
484 if (PCM_RUNTIME_CHECK(substream))
486 runtime = substream->runtime;
487 if (runtime->dma_area == NULL)
489 if (runtime->dma_buffer_p != &substream->dma_buffer) {
490 struct snd_card *card = substream->pcm->card;
492 /* it's a newly allocated buffer. release it now. */
493 do_free_pages(card, runtime->dma_buffer_p);
494 kfree(runtime->dma_buffer_p);
496 snd_pcm_set_runtime_buffer(substream, NULL);
499 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
501 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
502 size_t size, gfp_t gfp_flags)
504 struct snd_pcm_runtime *runtime;
506 if (PCM_RUNTIME_CHECK(substream))
508 runtime = substream->runtime;
509 if (runtime->dma_area) {
510 if (runtime->dma_bytes >= size)
511 return 0; /* already large enough */
512 vfree(runtime->dma_area);
514 runtime->dma_area = __vmalloc(size, gfp_flags);
515 if (!runtime->dma_area)
517 runtime->dma_bytes = size;
520 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
523 * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
524 * @substream: the substream with a buffer allocated by
525 * snd_pcm_lib_alloc_vmalloc_buffer()
527 * Return: Zero if successful, or a negative error code on failure.
529 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
531 struct snd_pcm_runtime *runtime;
533 if (PCM_RUNTIME_CHECK(substream))
535 runtime = substream->runtime;
536 vfree(runtime->dma_area);
537 runtime->dma_area = NULL;
540 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
543 * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
544 * @substream: the substream with a buffer allocated by
545 * snd_pcm_lib_alloc_vmalloc_buffer()
546 * @offset: offset in the buffer
548 * This function is to be used as the page callback in the PCM ops.
550 * Return: The page struct, or %NULL on failure.
552 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
553 unsigned long offset)
555 return vmalloc_to_page(substream->runtime->dma_area + offset);
557 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);