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 int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
35 size_t size, struct snd_dma_buffer *dmab)
39 if (max_alloc_per_card &&
40 card->total_pcm_alloc_bytes + size > max_alloc_per_card)
43 err = snd_dma_alloc_pages(type, dev, size, dmab);
45 mutex_lock(&card->memory_mutex);
46 card->total_pcm_alloc_bytes += dmab->bytes;
47 mutex_unlock(&card->memory_mutex);
52 static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
56 mutex_lock(&card->memory_mutex);
57 WARN_ON(card->total_pcm_alloc_bytes < dmab->bytes);
58 card->total_pcm_alloc_bytes -= dmab->bytes;
59 mutex_unlock(&card->memory_mutex);
60 snd_dma_free_pages(dmab);
65 * try to allocate as the large pages as possible.
66 * stores the resultant memory size in *res_size.
68 * the minimum size is snd_minimum_buffer. it should be power of 2.
70 static int preallocate_pcm_pages(struct snd_pcm_substream *substream,
71 size_t size, bool no_fallback)
73 struct snd_dma_buffer *dmab = &substream->dma_buffer;
74 struct snd_card *card = substream->pcm->card;
75 size_t orig_size = size;
79 err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
86 } while (size >= snd_minimum_buffer);
87 dmab->bytes = 0; /* tell error */
88 pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
89 substream->pcm->card->number, substream->pcm->device,
90 substream->stream ? 'c' : 'p', substream->number,
91 substream->pcm->name, orig_size);
96 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
97 * @substream: the pcm substream instance
99 * Releases the pre-allocated buffer of the given substream.
101 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
103 do_free_pages(substream->pcm->card, &substream->dma_buffer);
107 * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
108 * @pcm: the pcm instance
110 * Releases all the pre-allocated buffers on the given pcm.
112 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
114 struct snd_pcm_substream *substream;
117 for_each_pcm_substream(pcm, stream, substream)
118 snd_pcm_lib_preallocate_free(substream);
120 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
122 #ifdef CONFIG_SND_VERBOSE_PROCFS
124 * read callback for prealloc proc file
126 * prints the current allocated size in kB.
128 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
129 struct snd_info_buffer *buffer)
131 struct snd_pcm_substream *substream = entry->private_data;
132 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
136 * read callback for prealloc_max proc file
138 * prints the maximum allowed size in kB.
140 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
141 struct snd_info_buffer *buffer)
143 struct snd_pcm_substream *substream = entry->private_data;
144 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
148 * write callback for prealloc proc file
150 * accepts the preallocation size in kB.
152 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
153 struct snd_info_buffer *buffer)
155 struct snd_pcm_substream *substream = entry->private_data;
156 struct snd_card *card = substream->pcm->card;
157 char line[64], str[64];
159 struct snd_dma_buffer new_dmab;
161 mutex_lock(&substream->pcm->open_mutex);
162 if (substream->runtime) {
163 buffer->error = -EBUSY;
166 if (!snd_info_get_line(buffer, line, sizeof(line))) {
167 snd_info_get_str(str, line, sizeof(str));
168 size = simple_strtoul(str, NULL, 10) * 1024;
169 if ((size != 0 && size < 8192) || size > substream->dma_max) {
170 buffer->error = -EINVAL;
173 if (substream->dma_buffer.bytes == size)
175 memset(&new_dmab, 0, sizeof(new_dmab));
176 new_dmab.dev = substream->dma_buffer.dev;
178 if (do_alloc_pages(card,
179 substream->dma_buffer.dev.type,
180 substream->dma_buffer.dev.dev,
181 size, &new_dmab) < 0) {
182 buffer->error = -ENOMEM;
183 pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
184 substream->pcm->card->number, substream->pcm->device,
185 substream->stream ? 'c' : 'p', substream->number,
186 substream->pcm->name, size);
189 substream->buffer_bytes_max = size;
191 substream->buffer_bytes_max = UINT_MAX;
193 if (substream->dma_buffer.area)
194 do_free_pages(card, &substream->dma_buffer);
195 substream->dma_buffer = new_dmab;
197 buffer->error = -EINVAL;
200 mutex_unlock(&substream->pcm->open_mutex);
203 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
205 struct snd_info_entry *entry;
207 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
208 substream->proc_root);
210 snd_info_set_text_ops(entry, substream,
211 snd_pcm_lib_preallocate_proc_read);
212 entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
215 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
216 substream->proc_root);
218 snd_info_set_text_ops(entry, substream,
219 snd_pcm_lib_preallocate_max_proc_read);
222 #else /* !CONFIG_SND_VERBOSE_PROCFS */
223 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
226 #endif /* CONFIG_SND_VERBOSE_PROCFS */
229 * pre-allocate the buffer and create a proc file for the substream
231 static int preallocate_pages(struct snd_pcm_substream *substream,
232 int type, struct device *data,
233 size_t size, size_t max, bool managed)
237 if (snd_BUG_ON(substream->dma_buffer.dev.type))
240 substream->dma_buffer.dev.type = type;
241 substream->dma_buffer.dev.dev = data;
245 /* no fallback, only also inform -ENOMEM */
246 err = preallocate_pcm_pages(substream, size, true);
249 } else if (preallocate_dma &&
250 substream->number < maximum_substreams) {
251 err = preallocate_pcm_pages(substream, size, false);
252 if (err < 0 && err != -ENOMEM)
257 if (substream->dma_buffer.bytes > 0)
258 substream->buffer_bytes_max = substream->dma_buffer.bytes;
259 substream->dma_max = max;
261 preallocate_info_init(substream);
263 substream->managed_buffer_alloc = 1;
267 static int preallocate_pages_for_all(struct snd_pcm *pcm, int type,
268 void *data, size_t size, size_t max,
271 struct snd_pcm_substream *substream;
274 for_each_pcm_substream(pcm, stream, substream) {
275 err = preallocate_pages(substream, type, data, size, max, managed);
283 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
284 * @substream: the pcm substream instance
285 * @type: DMA type (SNDRV_DMA_TYPE_*)
286 * @data: DMA type dependent data
287 * @size: the requested pre-allocation size in bytes
288 * @max: the max. allowed pre-allocation size
290 * Do pre-allocation for the given DMA buffer type.
292 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
293 int type, struct device *data,
294 size_t size, size_t max)
296 preallocate_pages(substream, type, data, size, max, false);
298 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
301 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
302 * @pcm: the pcm instance
303 * @type: DMA type (SNDRV_DMA_TYPE_*)
304 * @data: DMA type dependent data
305 * @size: the requested pre-allocation size in bytes
306 * @max: the max. allowed pre-allocation size
308 * Do pre-allocation to all substreams of the given pcm for the
309 * specified DMA type.
311 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
312 int type, void *data,
313 size_t size, size_t max)
315 preallocate_pages_for_all(pcm, type, data, size, max, false);
317 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
320 * snd_pcm_set_managed_buffer - set up buffer management for a substream
321 * @substream: the pcm substream instance
322 * @type: DMA type (SNDRV_DMA_TYPE_*)
323 * @data: DMA type dependent data
324 * @size: the requested pre-allocation size in bytes
325 * @max: the max. allowed pre-allocation size
327 * Do pre-allocation for the given DMA buffer type, and set the managed
328 * buffer allocation mode to the given substream.
329 * In this mode, PCM core will allocate a buffer automatically before PCM
330 * hw_params ops call, and release the buffer after PCM hw_free ops call
331 * as well, so that the driver doesn't need to invoke the allocation and
332 * the release explicitly in its callback.
333 * When a buffer is actually allocated before the PCM hw_params call, it
334 * turns on the runtime buffer_changed flag for drivers changing their h/w
335 * parameters accordingly.
337 * When @size is non-zero and @max is zero, this tries to allocate for only
338 * the exact buffer size without fallback, and may return -ENOMEM.
339 * Otherwise, the function tries to allocate smaller chunks if the allocation
340 * fails. This is the behavior of snd_pcm_set_fixed_buffer().
342 * When both @size and @max are zero, the function only sets up the buffer
343 * for later dynamic allocations. It's used typically for buffers with
344 * SNDRV_DMA_TYPE_VMALLOC type.
346 * Upon successful buffer allocation and setup, the function returns 0.
348 int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
349 struct device *data, size_t size, size_t max)
351 return preallocate_pages(substream, type, data, size, max, true);
353 EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
356 * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
358 * @pcm: the pcm instance
359 * @type: DMA type (SNDRV_DMA_TYPE_*)
360 * @data: DMA type dependent data
361 * @size: the requested pre-allocation size in bytes
362 * @max: the max. allowed pre-allocation size
364 * Do pre-allocation to all substreams of the given pcm for the specified DMA
365 * type and size, and set the managed_buffer_alloc flag to each substream.
367 int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
369 size_t size, size_t max)
371 return preallocate_pages_for_all(pcm, type, data, size, max, true);
373 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
376 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
377 * @substream: the substream to allocate the DMA buffer to
378 * @size: the requested buffer size in bytes
380 * Allocates the DMA buffer on the BUS type given earlier to
381 * snd_pcm_lib_preallocate_xxx_pages().
383 * Return: 1 if the buffer is changed, 0 if not changed, or a negative
386 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
388 struct snd_card *card;
389 struct snd_pcm_runtime *runtime;
390 struct snd_dma_buffer *dmab = NULL;
392 if (PCM_RUNTIME_CHECK(substream))
394 if (snd_BUG_ON(substream->dma_buffer.dev.type ==
395 SNDRV_DMA_TYPE_UNKNOWN))
397 runtime = substream->runtime;
398 card = substream->pcm->card;
400 if (runtime->dma_buffer_p) {
401 /* perphaps, we might free the large DMA memory region
402 to save some space here, but the actual solution
403 costs us less time */
404 if (runtime->dma_buffer_p->bytes >= size) {
405 runtime->dma_bytes = size;
406 return 0; /* ok, do not change */
408 snd_pcm_lib_free_pages(substream);
410 if (substream->dma_buffer.area != NULL &&
411 substream->dma_buffer.bytes >= size) {
412 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
414 /* dma_max=0 means the fixed size preallocation */
415 if (substream->dma_buffer.area && !substream->dma_max)
417 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
420 dmab->dev = substream->dma_buffer.dev;
421 if (do_alloc_pages(card,
422 substream->dma_buffer.dev.type,
423 substream->dma_buffer.dev.dev,
426 pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
427 substream->pcm->card->number, substream->pcm->device,
428 substream->stream ? 'c' : 'p', substream->number,
429 substream->pcm->name, size);
433 snd_pcm_set_runtime_buffer(substream, dmab);
434 runtime->dma_bytes = size;
435 return 1; /* area was changed */
437 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
440 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
441 * @substream: the substream to release the DMA buffer
443 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
445 * Return: Zero if successful, or a negative error code on failure.
447 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
449 struct snd_pcm_runtime *runtime;
451 if (PCM_RUNTIME_CHECK(substream))
453 runtime = substream->runtime;
454 if (runtime->dma_area == NULL)
456 if (runtime->dma_buffer_p != &substream->dma_buffer) {
457 struct snd_card *card = substream->pcm->card;
459 /* it's a newly allocated buffer. release it now. */
460 do_free_pages(card, runtime->dma_buffer_p);
461 kfree(runtime->dma_buffer_p);
463 snd_pcm_set_runtime_buffer(substream, NULL);
466 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
468 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
469 size_t size, gfp_t gfp_flags)
471 struct snd_pcm_runtime *runtime;
473 if (PCM_RUNTIME_CHECK(substream))
475 runtime = substream->runtime;
476 if (runtime->dma_area) {
477 if (runtime->dma_bytes >= size)
478 return 0; /* already large enough */
479 vfree(runtime->dma_area);
481 runtime->dma_area = __vmalloc(size, gfp_flags);
482 if (!runtime->dma_area)
484 runtime->dma_bytes = size;
487 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
490 * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
491 * @substream: the substream with a buffer allocated by
492 * snd_pcm_lib_alloc_vmalloc_buffer()
494 * Return: Zero if successful, or a negative error code on failure.
496 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
498 struct snd_pcm_runtime *runtime;
500 if (PCM_RUNTIME_CHECK(substream))
502 runtime = substream->runtime;
503 vfree(runtime->dma_area);
504 runtime->dma_area = NULL;
507 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
510 * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
511 * @substream: the substream with a buffer allocated by
512 * snd_pcm_lib_alloc_vmalloc_buffer()
513 * @offset: offset in the buffer
515 * This function is to be used as the page callback in the PCM ops.
517 * Return: The page struct, or %NULL on failure.
519 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
520 unsigned long offset)
522 return vmalloc_to_page(substream->runtime->dma_area + offset);
524 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);