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 * release the preallocated buffer if not yet done.
95 static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
97 do_free_pages(substream->pcm->card, &substream->dma_buffer);
101 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
102 * @substream: the pcm substream instance
104 * Releases the pre-allocated buffer of the given substream.
106 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
108 snd_pcm_lib_preallocate_dma_free(substream);
112 * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
113 * @pcm: the pcm instance
115 * Releases all the pre-allocated buffers on the given pcm.
117 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
119 struct snd_pcm_substream *substream;
122 for (stream = 0; stream < 2; stream++)
123 for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
124 snd_pcm_lib_preallocate_free(substream);
126 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
128 #ifdef CONFIG_SND_VERBOSE_PROCFS
130 * read callback for prealloc proc file
132 * prints the current allocated size in kB.
134 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
135 struct snd_info_buffer *buffer)
137 struct snd_pcm_substream *substream = entry->private_data;
138 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
142 * read callback for prealloc_max proc file
144 * prints the maximum allowed size in kB.
146 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
147 struct snd_info_buffer *buffer)
149 struct snd_pcm_substream *substream = entry->private_data;
150 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
154 * write callback for prealloc proc file
156 * accepts the preallocation size in kB.
158 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
159 struct snd_info_buffer *buffer)
161 struct snd_pcm_substream *substream = entry->private_data;
162 struct snd_card *card = substream->pcm->card;
163 char line[64], str[64];
165 struct snd_dma_buffer new_dmab;
167 if (substream->runtime) {
168 buffer->error = -EBUSY;
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;
178 if (substream->dma_buffer.bytes == size)
180 memset(&new_dmab, 0, sizeof(new_dmab));
181 new_dmab.dev = substream->dma_buffer.dev;
183 if (do_alloc_pages(card,
184 substream->dma_buffer.dev.type,
185 substream->dma_buffer.dev.dev,
186 size, &new_dmab) < 0) {
187 buffer->error = -ENOMEM;
190 substream->buffer_bytes_max = size;
192 substream->buffer_bytes_max = UINT_MAX;
194 if (substream->dma_buffer.area)
195 do_free_pages(card, &substream->dma_buffer);
196 substream->dma_buffer = new_dmab;
198 buffer->error = -EINVAL;
202 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
204 struct snd_info_entry *entry;
206 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
207 substream->proc_root);
209 snd_info_set_text_ops(entry, substream,
210 snd_pcm_lib_preallocate_proc_read);
211 entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
214 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
215 substream->proc_root);
217 snd_info_set_text_ops(entry, substream,
218 snd_pcm_lib_preallocate_max_proc_read);
221 #else /* !CONFIG_SND_VERBOSE_PROCFS */
222 #define preallocate_info_init(s)
223 #endif /* CONFIG_SND_VERBOSE_PROCFS */
226 * pre-allocate the buffer and create a proc file for the substream
228 static void preallocate_pages(struct snd_pcm_substream *substream,
229 int type, struct device *data,
230 size_t size, size_t max, bool managed)
232 if (snd_BUG_ON(substream->dma_buffer.dev.type))
235 substream->dma_buffer.dev.type = type;
236 substream->dma_buffer.dev.dev = data;
238 if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
239 preallocate_pcm_pages(substream, size);
241 if (substream->dma_buffer.bytes > 0)
242 substream->buffer_bytes_max = substream->dma_buffer.bytes;
243 substream->dma_max = max;
245 preallocate_info_init(substream);
247 substream->managed_buffer_alloc = 1;
250 static void preallocate_pages_for_all(struct snd_pcm *pcm, int type,
251 void *data, size_t size, size_t max,
254 struct snd_pcm_substream *substream;
257 for (stream = 0; stream < 2; stream++)
258 for (substream = pcm->streams[stream].substream; substream;
259 substream = substream->next)
260 preallocate_pages(substream, type, data, size, max,
265 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
266 * @substream: the pcm substream instance
267 * @type: DMA type (SNDRV_DMA_TYPE_*)
268 * @data: DMA type dependent data
269 * @size: the requested pre-allocation size in bytes
270 * @max: the max. allowed pre-allocation size
272 * Do pre-allocation for the given DMA buffer type.
274 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
275 int type, struct device *data,
276 size_t size, size_t max)
278 preallocate_pages(substream, type, data, size, max, false);
280 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
283 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
284 * @pcm: the pcm 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 to all substreams of the given pcm for the
291 * specified DMA type.
293 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
294 int type, void *data,
295 size_t size, size_t max)
297 preallocate_pages_for_all(pcm, type, data, size, max, false);
299 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
302 * snd_pcm_set_managed_buffer - set up buffer management for a substream
303 * @substream: the pcm substream instance
304 * @type: DMA type (SNDRV_DMA_TYPE_*)
305 * @data: DMA type dependent data
306 * @size: the requested pre-allocation size in bytes
307 * @max: the max. allowed pre-allocation size
309 * Do pre-allocation for the given DMA buffer type, and set the managed
310 * buffer allocation mode to the given substream.
311 * In this mode, PCM core will allocate a buffer automatically before PCM
312 * hw_params ops call, and release the buffer after PCM hw_free ops call
313 * as well, so that the driver doesn't need to invoke the allocation and
314 * the release explicitly in its callback.
315 * When a buffer is actually allocated before the PCM hw_params call, it
316 * turns on the runtime buffer_changed flag for drivers changing their h/w
317 * parameters accordingly.
319 void snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
320 struct device *data, size_t size, size_t max)
322 preallocate_pages(substream, type, data, size, max, true);
324 EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
327 * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
329 * @pcm: the pcm instance
330 * @type: DMA type (SNDRV_DMA_TYPE_*)
331 * @data: DMA type dependent data
332 * @size: the requested pre-allocation size in bytes
333 * @max: the max. allowed pre-allocation size
335 * Do pre-allocation to all substreams of the given pcm for the specified DMA
336 * type and size, and set the managed_buffer_alloc flag to each substream.
338 void snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
340 size_t size, size_t max)
342 preallocate_pages_for_all(pcm, type, data, size, max, true);
344 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
346 #ifdef CONFIG_SND_DMA_SGBUF
348 * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
349 * @substream: the pcm substream instance
350 * @offset: the buffer offset
352 * Used as the page callback of PCM ops.
354 * Return: The page struct at the given buffer offset. %NULL on failure.
356 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
358 struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
360 unsigned int idx = offset >> PAGE_SHIFT;
361 if (idx >= (unsigned int)sgbuf->pages)
363 return sgbuf->page_table[idx];
365 #endif /* CONFIG_SND_DMA_SGBUF */
368 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
369 * @substream: the substream to allocate the DMA buffer to
370 * @size: the requested buffer size in bytes
372 * Allocates the DMA buffer on the BUS type given earlier to
373 * snd_pcm_lib_preallocate_xxx_pages().
375 * Return: 1 if the buffer is changed, 0 if not changed, or a negative
378 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
380 struct snd_card *card;
381 struct snd_pcm_runtime *runtime;
382 struct snd_dma_buffer *dmab = NULL;
384 if (PCM_RUNTIME_CHECK(substream))
386 if (snd_BUG_ON(substream->dma_buffer.dev.type ==
387 SNDRV_DMA_TYPE_UNKNOWN))
389 runtime = substream->runtime;
390 card = substream->pcm->card;
392 if (runtime->dma_buffer_p) {
393 /* perphaps, we might free the large DMA memory region
394 to save some space here, but the actual solution
395 costs us less time */
396 if (runtime->dma_buffer_p->bytes >= size) {
397 runtime->dma_bytes = size;
398 return 0; /* ok, do not change */
400 snd_pcm_lib_free_pages(substream);
402 if (substream->dma_buffer.area != NULL &&
403 substream->dma_buffer.bytes >= size) {
404 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
406 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
409 dmab->dev = substream->dma_buffer.dev;
410 if (do_alloc_pages(card,
411 substream->dma_buffer.dev.type,
412 substream->dma_buffer.dev.dev,
418 snd_pcm_set_runtime_buffer(substream, dmab);
419 runtime->dma_bytes = size;
420 return 1; /* area was changed */
422 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
425 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
426 * @substream: the substream to release the DMA buffer
428 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
430 * Return: Zero if successful, or a negative error code on failure.
432 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
434 struct snd_card *card = substream->pcm->card;
435 struct snd_pcm_runtime *runtime;
437 if (PCM_RUNTIME_CHECK(substream))
439 runtime = substream->runtime;
440 if (runtime->dma_area == NULL)
442 if (runtime->dma_buffer_p != &substream->dma_buffer) {
443 /* it's a newly allocated buffer. release it now. */
444 do_free_pages(card, runtime->dma_buffer_p);
445 kfree(runtime->dma_buffer_p);
447 snd_pcm_set_runtime_buffer(substream, NULL);
450 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
452 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
453 size_t size, gfp_t gfp_flags)
455 struct snd_pcm_runtime *runtime;
457 if (PCM_RUNTIME_CHECK(substream))
459 runtime = substream->runtime;
460 if (runtime->dma_area) {
461 if (runtime->dma_bytes >= size)
462 return 0; /* already large enough */
463 vfree(runtime->dma_area);
465 runtime->dma_area = __vmalloc(size, gfp_flags);
466 if (!runtime->dma_area)
468 runtime->dma_bytes = size;
471 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
474 * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
475 * @substream: the substream with a buffer allocated by
476 * snd_pcm_lib_alloc_vmalloc_buffer()
478 * Return: Zero if successful, or a negative error code on failure.
480 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
482 struct snd_pcm_runtime *runtime;
484 if (PCM_RUNTIME_CHECK(substream))
486 runtime = substream->runtime;
487 vfree(runtime->dma_area);
488 runtime->dma_area = NULL;
491 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
494 * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
495 * @substream: the substream with a buffer allocated by
496 * snd_pcm_lib_alloc_vmalloc_buffer()
497 * @offset: offset in the buffer
499 * This function is to be used as the page callback in the PCM ops.
501 * Return: The page struct, or %NULL on failure.
503 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
504 unsigned long offset)
506 return vmalloc_to_page(substream->runtime->dma_area + offset);
508 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);