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;
181 substream->buffer_bytes_max = size;
183 substream->buffer_bytes_max = UINT_MAX;
185 if (substream->dma_buffer.area)
186 do_free_pages(card, &substream->dma_buffer);
187 substream->dma_buffer = new_dmab;
189 buffer->error = -EINVAL;
193 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
195 struct snd_info_entry *entry;
197 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
198 substream->proc_root);
200 snd_info_set_text_ops(entry, substream,
201 snd_pcm_lib_preallocate_proc_read);
202 entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
205 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
206 substream->proc_root);
208 snd_info_set_text_ops(entry, substream,
209 snd_pcm_lib_preallocate_max_proc_read);
212 #else /* !CONFIG_SND_VERBOSE_PROCFS */
213 #define preallocate_info_init(s)
214 #endif /* CONFIG_SND_VERBOSE_PROCFS */
217 * pre-allocate the buffer and create a proc file for the substream
219 static void preallocate_pages(struct snd_pcm_substream *substream,
220 int type, struct device *data,
221 size_t size, size_t max, bool managed)
223 if (snd_BUG_ON(substream->dma_buffer.dev.type))
226 substream->dma_buffer.dev.type = type;
227 substream->dma_buffer.dev.dev = data;
229 if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
230 preallocate_pcm_pages(substream, size);
232 if (substream->dma_buffer.bytes > 0)
233 substream->buffer_bytes_max = substream->dma_buffer.bytes;
234 substream->dma_max = max;
236 preallocate_info_init(substream);
238 substream->managed_buffer_alloc = 1;
241 static void preallocate_pages_for_all(struct snd_pcm *pcm, int type,
242 void *data, size_t size, size_t max,
245 struct snd_pcm_substream *substream;
248 for_each_pcm_substream(pcm, stream, substream)
249 preallocate_pages(substream, type, data, size, max, managed);
253 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
254 * @substream: the pcm substream instance
255 * @type: DMA type (SNDRV_DMA_TYPE_*)
256 * @data: DMA type dependent data
257 * @size: the requested pre-allocation size in bytes
258 * @max: the max. allowed pre-allocation size
260 * Do pre-allocation for the given DMA buffer type.
262 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
263 int type, struct device *data,
264 size_t size, size_t max)
266 preallocate_pages(substream, type, data, size, max, false);
268 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
271 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
272 * @pcm: the pcm instance
273 * @type: DMA type (SNDRV_DMA_TYPE_*)
274 * @data: DMA type dependent data
275 * @size: the requested pre-allocation size in bytes
276 * @max: the max. allowed pre-allocation size
278 * Do pre-allocation to all substreams of the given pcm for the
279 * specified DMA type.
281 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
282 int type, void *data,
283 size_t size, size_t max)
285 preallocate_pages_for_all(pcm, type, data, size, max, false);
287 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
290 * snd_pcm_set_managed_buffer - set up buffer management for a substream
291 * @substream: the pcm substream instance
292 * @type: DMA type (SNDRV_DMA_TYPE_*)
293 * @data: DMA type dependent data
294 * @size: the requested pre-allocation size in bytes
295 * @max: the max. allowed pre-allocation size
297 * Do pre-allocation for the given DMA buffer type, and set the managed
298 * buffer allocation mode to the given substream.
299 * In this mode, PCM core will allocate a buffer automatically before PCM
300 * hw_params ops call, and release the buffer after PCM hw_free ops call
301 * as well, so that the driver doesn't need to invoke the allocation and
302 * the release explicitly in its callback.
303 * When a buffer is actually allocated before the PCM hw_params call, it
304 * turns on the runtime buffer_changed flag for drivers changing their h/w
305 * parameters accordingly.
307 void snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
308 struct device *data, size_t size, size_t max)
310 preallocate_pages(substream, type, data, size, max, true);
312 EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
315 * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
317 * @pcm: the pcm instance
318 * @type: DMA type (SNDRV_DMA_TYPE_*)
319 * @data: DMA type dependent data
320 * @size: the requested pre-allocation size in bytes
321 * @max: the max. allowed pre-allocation size
323 * Do pre-allocation to all substreams of the given pcm for the specified DMA
324 * type and size, and set the managed_buffer_alloc flag to each substream.
326 void snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
328 size_t size, size_t max)
330 preallocate_pages_for_all(pcm, type, data, size, max, true);
332 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
334 #ifdef CONFIG_SND_DMA_SGBUF
336 * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
337 * @substream: the pcm substream instance
338 * @offset: the buffer offset
340 * Used as the page callback of PCM ops.
342 * Return: The page struct at the given buffer offset. %NULL on failure.
344 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
346 struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
348 unsigned int idx = offset >> PAGE_SHIFT;
349 if (idx >= (unsigned int)sgbuf->pages)
351 return sgbuf->page_table[idx];
353 #endif /* CONFIG_SND_DMA_SGBUF */
356 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
357 * @substream: the substream to allocate the DMA buffer to
358 * @size: the requested buffer size in bytes
360 * Allocates the DMA buffer on the BUS type given earlier to
361 * snd_pcm_lib_preallocate_xxx_pages().
363 * Return: 1 if the buffer is changed, 0 if not changed, or a negative
366 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
368 struct snd_card *card;
369 struct snd_pcm_runtime *runtime;
370 struct snd_dma_buffer *dmab = NULL;
372 if (PCM_RUNTIME_CHECK(substream))
374 if (snd_BUG_ON(substream->dma_buffer.dev.type ==
375 SNDRV_DMA_TYPE_UNKNOWN))
377 runtime = substream->runtime;
378 card = substream->pcm->card;
380 if (runtime->dma_buffer_p) {
381 /* perphaps, we might free the large DMA memory region
382 to save some space here, but the actual solution
383 costs us less time */
384 if (runtime->dma_buffer_p->bytes >= size) {
385 runtime->dma_bytes = size;
386 return 0; /* ok, do not change */
388 snd_pcm_lib_free_pages(substream);
390 if (substream->dma_buffer.area != NULL &&
391 substream->dma_buffer.bytes >= size) {
392 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
394 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
397 dmab->dev = substream->dma_buffer.dev;
398 if (do_alloc_pages(card,
399 substream->dma_buffer.dev.type,
400 substream->dma_buffer.dev.dev,
406 snd_pcm_set_runtime_buffer(substream, dmab);
407 runtime->dma_bytes = size;
408 return 1; /* area was changed */
410 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
413 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
414 * @substream: the substream to release the DMA buffer
416 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
418 * Return: Zero if successful, or a negative error code on failure.
420 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
422 struct snd_card *card = substream->pcm->card;
423 struct snd_pcm_runtime *runtime;
425 if (PCM_RUNTIME_CHECK(substream))
427 runtime = substream->runtime;
428 if (runtime->dma_area == NULL)
430 if (runtime->dma_buffer_p != &substream->dma_buffer) {
431 /* it's a newly allocated buffer. release it now. */
432 do_free_pages(card, runtime->dma_buffer_p);
433 kfree(runtime->dma_buffer_p);
435 snd_pcm_set_runtime_buffer(substream, NULL);
438 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
440 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
441 size_t size, gfp_t gfp_flags)
443 struct snd_pcm_runtime *runtime;
445 if (PCM_RUNTIME_CHECK(substream))
447 runtime = substream->runtime;
448 if (runtime->dma_area) {
449 if (runtime->dma_bytes >= size)
450 return 0; /* already large enough */
451 vfree(runtime->dma_area);
453 runtime->dma_area = __vmalloc(size, gfp_flags);
454 if (!runtime->dma_area)
456 runtime->dma_bytes = size;
459 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
462 * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
463 * @substream: the substream with a buffer allocated by
464 * snd_pcm_lib_alloc_vmalloc_buffer()
466 * Return: Zero if successful, or a negative error code on failure.
468 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
470 struct snd_pcm_runtime *runtime;
472 if (PCM_RUNTIME_CHECK(substream))
474 runtime = substream->runtime;
475 vfree(runtime->dma_area);
476 runtime->dma_area = NULL;
479 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
482 * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
483 * @substream: the substream with a buffer allocated by
484 * snd_pcm_lib_alloc_vmalloc_buffer()
485 * @offset: offset in the buffer
487 * This function is to be used as the page callback in the PCM ops.
489 * Return: The page struct, or %NULL on failure.
491 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
492 unsigned long offset)
494 return vmalloc_to_page(substream->runtime->dma_area + offset);
496 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);