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, size_t size)
72 struct snd_dma_buffer *dmab = &substream->dma_buffer;
73 struct snd_card *card = substream->pcm->card;
74 size_t orig_size = size;
78 err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
83 } while (size >= snd_minimum_buffer);
84 dmab->bytes = 0; /* tell error */
85 pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
86 substream->pcm->card->number, substream->pcm->device,
87 substream->stream ? 'c' : 'p', substream->number,
88 substream->pcm->name, orig_size);
93 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
94 * @substream: the pcm substream instance
96 * Releases the pre-allocated buffer of the given substream.
98 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
100 do_free_pages(substream->pcm->card, &substream->dma_buffer);
104 * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
105 * @pcm: the pcm instance
107 * Releases all the pre-allocated buffers on the given pcm.
109 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
111 struct snd_pcm_substream *substream;
114 for_each_pcm_substream(pcm, stream, substream)
115 snd_pcm_lib_preallocate_free(substream);
117 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
119 #ifdef CONFIG_SND_VERBOSE_PROCFS
121 * read callback for prealloc proc file
123 * prints the current allocated size in kB.
125 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
126 struct snd_info_buffer *buffer)
128 struct snd_pcm_substream *substream = entry->private_data;
129 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
133 * read callback for prealloc_max proc file
135 * prints the maximum allowed size in kB.
137 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
138 struct snd_info_buffer *buffer)
140 struct snd_pcm_substream *substream = entry->private_data;
141 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
145 * write callback for prealloc proc file
147 * accepts the preallocation size in kB.
149 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
150 struct snd_info_buffer *buffer)
152 struct snd_pcm_substream *substream = entry->private_data;
153 struct snd_card *card = substream->pcm->card;
154 char line[64], str[64];
156 struct snd_dma_buffer new_dmab;
158 if (substream->runtime) {
159 buffer->error = -EBUSY;
162 if (!snd_info_get_line(buffer, line, sizeof(line))) {
163 snd_info_get_str(str, line, sizeof(str));
164 size = simple_strtoul(str, NULL, 10) * 1024;
165 if ((size != 0 && size < 8192) || size > substream->dma_max) {
166 buffer->error = -EINVAL;
169 if (substream->dma_buffer.bytes == size)
171 memset(&new_dmab, 0, sizeof(new_dmab));
172 new_dmab.dev = substream->dma_buffer.dev;
174 if (do_alloc_pages(card,
175 substream->dma_buffer.dev.type,
176 substream->dma_buffer.dev.dev,
177 size, &new_dmab) < 0) {
178 buffer->error = -ENOMEM;
179 pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
180 substream->pcm->card->number, substream->pcm->device,
181 substream->stream ? 'c' : 'p', substream->number,
182 substream->pcm->name, size);
185 substream->buffer_bytes_max = size;
187 substream->buffer_bytes_max = UINT_MAX;
189 if (substream->dma_buffer.area)
190 do_free_pages(card, &substream->dma_buffer);
191 substream->dma_buffer = new_dmab;
193 buffer->error = -EINVAL;
197 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
199 struct snd_info_entry *entry;
201 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
202 substream->proc_root);
204 snd_info_set_text_ops(entry, substream,
205 snd_pcm_lib_preallocate_proc_read);
206 entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
209 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
210 substream->proc_root);
212 snd_info_set_text_ops(entry, substream,
213 snd_pcm_lib_preallocate_max_proc_read);
216 #else /* !CONFIG_SND_VERBOSE_PROCFS */
217 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
220 #endif /* CONFIG_SND_VERBOSE_PROCFS */
223 * pre-allocate the buffer and create a proc file for the substream
225 static void preallocate_pages(struct snd_pcm_substream *substream,
226 int type, struct device *data,
227 size_t size, size_t max, bool managed)
229 if (snd_BUG_ON(substream->dma_buffer.dev.type))
232 substream->dma_buffer.dev.type = type;
233 substream->dma_buffer.dev.dev = data;
235 if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
236 preallocate_pcm_pages(substream, size);
238 if (substream->dma_buffer.bytes > 0)
239 substream->buffer_bytes_max = substream->dma_buffer.bytes;
240 substream->dma_max = max;
242 preallocate_info_init(substream);
244 substream->managed_buffer_alloc = 1;
247 static void preallocate_pages_for_all(struct snd_pcm *pcm, int type,
248 void *data, size_t size, size_t max,
251 struct snd_pcm_substream *substream;
254 for_each_pcm_substream(pcm, stream, substream)
255 preallocate_pages(substream, type, data, size, max, managed);
259 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
260 * @substream: the pcm substream instance
261 * @type: DMA type (SNDRV_DMA_TYPE_*)
262 * @data: DMA type dependent data
263 * @size: the requested pre-allocation size in bytes
264 * @max: the max. allowed pre-allocation size
266 * Do pre-allocation for the given DMA buffer type.
268 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
269 int type, struct device *data,
270 size_t size, size_t max)
272 preallocate_pages(substream, type, data, size, max, false);
274 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
277 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
278 * @pcm: the pcm instance
279 * @type: DMA type (SNDRV_DMA_TYPE_*)
280 * @data: DMA type dependent data
281 * @size: the requested pre-allocation size in bytes
282 * @max: the max. allowed pre-allocation size
284 * Do pre-allocation to all substreams of the given pcm for the
285 * specified DMA type.
287 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
288 int type, void *data,
289 size_t size, size_t max)
291 preallocate_pages_for_all(pcm, type, data, size, max, false);
293 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
296 * snd_pcm_set_managed_buffer - set up buffer management for a substream
297 * @substream: the pcm substream instance
298 * @type: DMA type (SNDRV_DMA_TYPE_*)
299 * @data: DMA type dependent data
300 * @size: the requested pre-allocation size in bytes
301 * @max: the max. allowed pre-allocation size
303 * Do pre-allocation for the given DMA buffer type, and set the managed
304 * buffer allocation mode to the given substream.
305 * In this mode, PCM core will allocate a buffer automatically before PCM
306 * hw_params ops call, and release the buffer after PCM hw_free ops call
307 * as well, so that the driver doesn't need to invoke the allocation and
308 * the release explicitly in its callback.
309 * When a buffer is actually allocated before the PCM hw_params call, it
310 * turns on the runtime buffer_changed flag for drivers changing their h/w
311 * parameters accordingly.
313 void snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
314 struct device *data, size_t size, size_t max)
316 preallocate_pages(substream, type, data, size, max, true);
318 EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
321 * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
323 * @pcm: the pcm instance
324 * @type: DMA type (SNDRV_DMA_TYPE_*)
325 * @data: DMA type dependent data
326 * @size: the requested pre-allocation size in bytes
327 * @max: the max. allowed pre-allocation size
329 * Do pre-allocation to all substreams of the given pcm for the specified DMA
330 * type and size, and set the managed_buffer_alloc flag to each substream.
332 void snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
334 size_t size, size_t max)
336 preallocate_pages_for_all(pcm, type, data, size, max, true);
338 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
340 #ifdef CONFIG_SND_DMA_SGBUF
342 * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
343 * @substream: the pcm substream instance
344 * @offset: the buffer offset
346 * Used as the page callback of PCM ops.
348 * Return: The page struct at the given buffer offset. %NULL on failure.
350 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
352 struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
354 unsigned int idx = offset >> PAGE_SHIFT;
355 if (idx >= (unsigned int)sgbuf->pages)
357 return sgbuf->page_table[idx];
359 #endif /* CONFIG_SND_DMA_SGBUF */
362 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
363 * @substream: the substream to allocate the DMA buffer to
364 * @size: the requested buffer size in bytes
366 * Allocates the DMA buffer on the BUS type given earlier to
367 * snd_pcm_lib_preallocate_xxx_pages().
369 * Return: 1 if the buffer is changed, 0 if not changed, or a negative
372 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
374 struct snd_card *card;
375 struct snd_pcm_runtime *runtime;
376 struct snd_dma_buffer *dmab = NULL;
378 if (PCM_RUNTIME_CHECK(substream))
380 if (snd_BUG_ON(substream->dma_buffer.dev.type ==
381 SNDRV_DMA_TYPE_UNKNOWN))
383 runtime = substream->runtime;
384 card = substream->pcm->card;
386 if (runtime->dma_buffer_p) {
387 /* perphaps, we might free the large DMA memory region
388 to save some space here, but the actual solution
389 costs us less time */
390 if (runtime->dma_buffer_p->bytes >= size) {
391 runtime->dma_bytes = size;
392 return 0; /* ok, do not change */
394 snd_pcm_lib_free_pages(substream);
396 if (substream->dma_buffer.area != NULL &&
397 substream->dma_buffer.bytes >= size) {
398 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
400 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
403 dmab->dev = substream->dma_buffer.dev;
404 if (do_alloc_pages(card,
405 substream->dma_buffer.dev.type,
406 substream->dma_buffer.dev.dev,
409 pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
410 substream->pcm->card->number, substream->pcm->device,
411 substream->stream ? 'c' : 'p', substream->number,
412 substream->pcm->name, size);
416 snd_pcm_set_runtime_buffer(substream, dmab);
417 runtime->dma_bytes = size;
418 return 1; /* area was changed */
420 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
423 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
424 * @substream: the substream to release the DMA buffer
426 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
428 * Return: Zero if successful, or a negative error code on failure.
430 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
432 struct snd_card *card = substream->pcm->card;
433 struct snd_pcm_runtime *runtime;
435 if (PCM_RUNTIME_CHECK(substream))
437 runtime = substream->runtime;
438 if (runtime->dma_area == NULL)
440 if (runtime->dma_buffer_p != &substream->dma_buffer) {
441 /* it's a newly allocated buffer. release it now. */
442 do_free_pages(card, runtime->dma_buffer_p);
443 kfree(runtime->dma_buffer_p);
445 snd_pcm_set_runtime_buffer(substream, NULL);
448 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
450 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
451 size_t size, gfp_t gfp_flags)
453 struct snd_pcm_runtime *runtime;
455 if (PCM_RUNTIME_CHECK(substream))
457 runtime = substream->runtime;
458 if (runtime->dma_area) {
459 if (runtime->dma_bytes >= size)
460 return 0; /* already large enough */
461 vfree(runtime->dma_area);
463 runtime->dma_area = __vmalloc(size, gfp_flags);
464 if (!runtime->dma_area)
466 runtime->dma_bytes = size;
469 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
472 * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
473 * @substream: the substream with a buffer allocated by
474 * snd_pcm_lib_alloc_vmalloc_buffer()
476 * Return: Zero if successful, or a negative error code on failure.
478 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
480 struct snd_pcm_runtime *runtime;
482 if (PCM_RUNTIME_CHECK(substream))
484 runtime = substream->runtime;
485 vfree(runtime->dma_area);
486 runtime->dma_area = NULL;
489 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
492 * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
493 * @substream: the substream with a buffer allocated by
494 * snd_pcm_lib_alloc_vmalloc_buffer()
495 * @offset: offset in the buffer
497 * This function is to be used as the page callback in the PCM ops.
499 * Return: The page struct, or %NULL on failure.
501 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
502 unsigned long offset)
504 return vmalloc_to_page(substream->runtime->dma_area + offset);
506 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);