1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Digital Audio (PCM) abstract layer
4 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5 */
6
7 #include <linux/io.h>
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"
19
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.");
23
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.");
27
28 static const size_t snd_minimum_buffer = 16384;
29
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.");
33
do_alloc_pages(struct snd_card * card,int type,struct device * dev,int str,size_t size,struct snd_dma_buffer * dmab)34 static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
35 int str, size_t size, struct snd_dma_buffer *dmab)
36 {
37 enum dma_data_direction dir;
38 int err;
39
40 if (max_alloc_per_card &&
41 card->total_pcm_alloc_bytes + size > max_alloc_per_card)
42 return -ENOMEM;
43
44 if (str == SNDRV_PCM_STREAM_PLAYBACK)
45 dir = DMA_TO_DEVICE;
46 else
47 dir = DMA_FROM_DEVICE;
48 err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab);
49 if (!err) {
50 mutex_lock(&card->memory_mutex);
51 card->total_pcm_alloc_bytes += dmab->bytes;
52 mutex_unlock(&card->memory_mutex);
53 }
54 return err;
55 }
56
do_free_pages(struct snd_card * card,struct snd_dma_buffer * dmab)57 static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
58 {
59 if (!dmab->area)
60 return;
61 mutex_lock(&card->memory_mutex);
62 WARN_ON(card->total_pcm_alloc_bytes < dmab->bytes);
63 card->total_pcm_alloc_bytes -= dmab->bytes;
64 mutex_unlock(&card->memory_mutex);
65 snd_dma_free_pages(dmab);
66 dmab->area = NULL;
67 }
68
69 /*
70 * try to allocate as the large pages as possible.
71 * stores the resultant memory size in *res_size.
72 *
73 * the minimum size is snd_minimum_buffer. it should be power of 2.
74 */
preallocate_pcm_pages(struct snd_pcm_substream * substream,size_t size,bool no_fallback)75 static int preallocate_pcm_pages(struct snd_pcm_substream *substream,
76 size_t size, bool no_fallback)
77 {
78 struct snd_dma_buffer *dmab = &substream->dma_buffer;
79 struct snd_card *card = substream->pcm->card;
80 size_t orig_size = size;
81 int err;
82
83 do {
84 err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
85 substream->stream, size, dmab);
86 if (err != -ENOMEM)
87 return err;
88 if (no_fallback)
89 break;
90 size >>= 1;
91 } while (size >= snd_minimum_buffer);
92 dmab->bytes = 0; /* tell error */
93 pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
94 substream->pcm->card->number, substream->pcm->device,
95 substream->stream ? 'c' : 'p', substream->number,
96 substream->pcm->name, orig_size);
97 return -ENOMEM;
98 }
99
100 /**
101 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
102 * @substream: the pcm substream instance
103 *
104 * Releases the pre-allocated buffer of the given substream.
105 */
snd_pcm_lib_preallocate_free(struct snd_pcm_substream * substream)106 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
107 {
108 do_free_pages(substream->pcm->card, &substream->dma_buffer);
109 }
110
111 /**
112 * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
113 * @pcm: the pcm instance
114 *
115 * Releases all the pre-allocated buffers on the given pcm.
116 */
snd_pcm_lib_preallocate_free_for_all(struct snd_pcm * pcm)117 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
118 {
119 struct snd_pcm_substream *substream;
120 int stream;
121
122 for_each_pcm_substream(pcm, stream, substream)
123 snd_pcm_lib_preallocate_free(substream);
124 }
125 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
126
127 #ifdef CONFIG_SND_VERBOSE_PROCFS
128 /*
129 * read callback for prealloc proc file
130 *
131 * prints the current allocated size in kB.
132 */
snd_pcm_lib_preallocate_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)133 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
134 struct snd_info_buffer *buffer)
135 {
136 struct snd_pcm_substream *substream = entry->private_data;
137 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
138 }
139
140 /*
141 * read callback for prealloc_max proc file
142 *
143 * prints the maximum allowed size in kB.
144 */
snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)145 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
146 struct snd_info_buffer *buffer)
147 {
148 struct snd_pcm_substream *substream = entry->private_data;
149 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
150 }
151
152 /*
153 * write callback for prealloc proc file
154 *
155 * accepts the preallocation size in kB.
156 */
snd_pcm_lib_preallocate_proc_write(struct snd_info_entry * entry,struct snd_info_buffer * buffer)157 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
158 struct snd_info_buffer *buffer)
159 {
160 struct snd_pcm_substream *substream = entry->private_data;
161 struct snd_card *card = substream->pcm->card;
162 char line[64], str[64];
163 size_t size;
164 struct snd_dma_buffer new_dmab;
165
166 mutex_lock(&substream->pcm->open_mutex);
167 if (substream->runtime) {
168 buffer->error = -EBUSY;
169 goto unlock;
170 }
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;
176 goto unlock;
177 }
178 if (substream->dma_buffer.bytes == size)
179 goto unlock;
180 memset(&new_dmab, 0, sizeof(new_dmab));
181 new_dmab.dev = substream->dma_buffer.dev;
182 if (size > 0) {
183 if (do_alloc_pages(card,
184 substream->dma_buffer.dev.type,
185 substream->dma_buffer.dev.dev,
186 substream->stream,
187 size, &new_dmab) < 0) {
188 buffer->error = -ENOMEM;
189 pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
190 substream->pcm->card->number, substream->pcm->device,
191 substream->stream ? 'c' : 'p', substream->number,
192 substream->pcm->name, size);
193 goto unlock;
194 }
195 substream->buffer_bytes_max = size;
196 } else {
197 substream->buffer_bytes_max = UINT_MAX;
198 }
199 if (substream->dma_buffer.area)
200 do_free_pages(card, &substream->dma_buffer);
201 substream->dma_buffer = new_dmab;
202 } else {
203 buffer->error = -EINVAL;
204 }
205 unlock:
206 mutex_unlock(&substream->pcm->open_mutex);
207 }
208
preallocate_info_init(struct snd_pcm_substream * substream)209 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
210 {
211 struct snd_info_entry *entry;
212
213 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
214 substream->proc_root);
215 if (entry) {
216 snd_info_set_text_ops(entry, substream,
217 snd_pcm_lib_preallocate_proc_read);
218 entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
219 entry->mode |= 0200;
220 }
221 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
222 substream->proc_root);
223 if (entry)
224 snd_info_set_text_ops(entry, substream,
225 snd_pcm_lib_preallocate_max_proc_read);
226 }
227
228 #else /* !CONFIG_SND_VERBOSE_PROCFS */
preallocate_info_init(struct snd_pcm_substream * substream)229 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
230 {
231 }
232 #endif /* CONFIG_SND_VERBOSE_PROCFS */
233
234 /*
235 * pre-allocate the buffer and create a proc file for the substream
236 */
preallocate_pages(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max,bool managed)237 static int preallocate_pages(struct snd_pcm_substream *substream,
238 int type, struct device *data,
239 size_t size, size_t max, bool managed)
240 {
241 int err;
242
243 if (snd_BUG_ON(substream->dma_buffer.dev.type))
244 return -EINVAL;
245
246 substream->dma_buffer.dev.type = type;
247 substream->dma_buffer.dev.dev = data;
248
249 if (size > 0) {
250 if (!max) {
251 /* no fallback, only also inform -ENOMEM */
252 err = preallocate_pcm_pages(substream, size, true);
253 if (err < 0)
254 return err;
255 } else if (preallocate_dma &&
256 substream->number < maximum_substreams) {
257 err = preallocate_pcm_pages(substream, size, false);
258 if (err < 0 && err != -ENOMEM)
259 return err;
260 }
261 }
262
263 if (substream->dma_buffer.bytes > 0)
264 substream->buffer_bytes_max = substream->dma_buffer.bytes;
265 substream->dma_max = max;
266 if (max > 0)
267 preallocate_info_init(substream);
268 if (managed)
269 substream->managed_buffer_alloc = 1;
270 return 0;
271 }
272
preallocate_pages_for_all(struct snd_pcm * pcm,int type,void * data,size_t size,size_t max,bool managed)273 static int preallocate_pages_for_all(struct snd_pcm *pcm, int type,
274 void *data, size_t size, size_t max,
275 bool managed)
276 {
277 struct snd_pcm_substream *substream;
278 int stream, err;
279
280 for_each_pcm_substream(pcm, stream, substream) {
281 err = preallocate_pages(substream, type, data, size, max, managed);
282 if (err < 0)
283 return err;
284 }
285 return 0;
286 }
287
288 /**
289 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
290 * @substream: the pcm substream instance
291 * @type: DMA type (SNDRV_DMA_TYPE_*)
292 * @data: DMA type dependent data
293 * @size: the requested pre-allocation size in bytes
294 * @max: the max. allowed pre-allocation size
295 *
296 * Do pre-allocation for the given DMA buffer type.
297 */
snd_pcm_lib_preallocate_pages(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max)298 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
299 int type, struct device *data,
300 size_t size, size_t max)
301 {
302 preallocate_pages(substream, type, data, size, max, false);
303 }
304 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
305
306 /**
307 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
308 * @pcm: the pcm instance
309 * @type: DMA type (SNDRV_DMA_TYPE_*)
310 * @data: DMA type dependent data
311 * @size: the requested pre-allocation size in bytes
312 * @max: the max. allowed pre-allocation size
313 *
314 * Do pre-allocation to all substreams of the given pcm for the
315 * specified DMA type.
316 */
snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm * pcm,int type,void * data,size_t size,size_t max)317 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
318 int type, void *data,
319 size_t size, size_t max)
320 {
321 preallocate_pages_for_all(pcm, type, data, size, max, false);
322 }
323 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
324
325 /**
326 * snd_pcm_set_managed_buffer - set up buffer management for a substream
327 * @substream: the pcm substream instance
328 * @type: DMA type (SNDRV_DMA_TYPE_*)
329 * @data: DMA type dependent data
330 * @size: the requested pre-allocation size in bytes
331 * @max: the max. allowed pre-allocation size
332 *
333 * Do pre-allocation for the given DMA buffer type, and set the managed
334 * buffer allocation mode to the given substream.
335 * In this mode, PCM core will allocate a buffer automatically before PCM
336 * hw_params ops call, and release the buffer after PCM hw_free ops call
337 * as well, so that the driver doesn't need to invoke the allocation and
338 * the release explicitly in its callback.
339 * When a buffer is actually allocated before the PCM hw_params call, it
340 * turns on the runtime buffer_changed flag for drivers changing their h/w
341 * parameters accordingly.
342 *
343 * When @size is non-zero and @max is zero, this tries to allocate for only
344 * the exact buffer size without fallback, and may return -ENOMEM.
345 * Otherwise, the function tries to allocate smaller chunks if the allocation
346 * fails. This is the behavior of snd_pcm_set_fixed_buffer().
347 *
348 * When both @size and @max are zero, the function only sets up the buffer
349 * for later dynamic allocations. It's used typically for buffers with
350 * SNDRV_DMA_TYPE_VMALLOC type.
351 *
352 * Upon successful buffer allocation and setup, the function returns 0.
353 */
snd_pcm_set_managed_buffer(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max)354 int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
355 struct device *data, size_t size, size_t max)
356 {
357 return preallocate_pages(substream, type, data, size, max, true);
358 }
359 EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
360
361 /**
362 * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
363 * for all substreams
364 * @pcm: the pcm instance
365 * @type: DMA type (SNDRV_DMA_TYPE_*)
366 * @data: DMA type dependent data
367 * @size: the requested pre-allocation size in bytes
368 * @max: the max. allowed pre-allocation size
369 *
370 * Do pre-allocation to all substreams of the given pcm for the specified DMA
371 * type and size, and set the managed_buffer_alloc flag to each substream.
372 */
snd_pcm_set_managed_buffer_all(struct snd_pcm * pcm,int type,struct device * data,size_t size,size_t max)373 int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
374 struct device *data,
375 size_t size, size_t max)
376 {
377 return preallocate_pages_for_all(pcm, type, data, size, max, true);
378 }
379 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
380
381 /**
382 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
383 * @substream: the substream to allocate the DMA buffer to
384 * @size: the requested buffer size in bytes
385 *
386 * Allocates the DMA buffer on the BUS type given earlier to
387 * snd_pcm_lib_preallocate_xxx_pages().
388 *
389 * Return: 1 if the buffer is changed, 0 if not changed, or a negative
390 * code on failure.
391 */
snd_pcm_lib_malloc_pages(struct snd_pcm_substream * substream,size_t size)392 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
393 {
394 struct snd_card *card;
395 struct snd_pcm_runtime *runtime;
396 struct snd_dma_buffer *dmab = NULL;
397
398 if (PCM_RUNTIME_CHECK(substream))
399 return -EINVAL;
400 if (snd_BUG_ON(substream->dma_buffer.dev.type ==
401 SNDRV_DMA_TYPE_UNKNOWN))
402 return -EINVAL;
403 runtime = substream->runtime;
404 card = substream->pcm->card;
405
406 if (runtime->dma_buffer_p) {
407 /* perphaps, we might free the large DMA memory region
408 to save some space here, but the actual solution
409 costs us less time */
410 if (runtime->dma_buffer_p->bytes >= size) {
411 runtime->dma_bytes = size;
412 return 0; /* ok, do not change */
413 }
414 snd_pcm_lib_free_pages(substream);
415 }
416 if (substream->dma_buffer.area != NULL &&
417 substream->dma_buffer.bytes >= size) {
418 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
419 } else {
420 /* dma_max=0 means the fixed size preallocation */
421 if (substream->dma_buffer.area && !substream->dma_max)
422 return -ENOMEM;
423 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
424 if (! dmab)
425 return -ENOMEM;
426 dmab->dev = substream->dma_buffer.dev;
427 if (do_alloc_pages(card,
428 substream->dma_buffer.dev.type,
429 substream->dma_buffer.dev.dev,
430 substream->stream,
431 size, dmab) < 0) {
432 kfree(dmab);
433 pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
434 substream->pcm->card->number, substream->pcm->device,
435 substream->stream ? 'c' : 'p', substream->number,
436 substream->pcm->name, size);
437 return -ENOMEM;
438 }
439 }
440 snd_pcm_set_runtime_buffer(substream, dmab);
441 runtime->dma_bytes = size;
442 return 1; /* area was changed */
443 }
444 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
445
446 /**
447 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
448 * @substream: the substream to release the DMA buffer
449 *
450 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
451 *
452 * Return: Zero if successful, or a negative error code on failure.
453 */
snd_pcm_lib_free_pages(struct snd_pcm_substream * substream)454 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
455 {
456 struct snd_pcm_runtime *runtime;
457
458 if (PCM_RUNTIME_CHECK(substream))
459 return -EINVAL;
460 runtime = substream->runtime;
461 if (runtime->dma_area == NULL)
462 return 0;
463 if (runtime->dma_buffer_p != &substream->dma_buffer) {
464 struct snd_card *card = substream->pcm->card;
465
466 /* it's a newly allocated buffer. release it now. */
467 do_free_pages(card, runtime->dma_buffer_p);
468 kfree(runtime->dma_buffer_p);
469 }
470 snd_pcm_set_runtime_buffer(substream, NULL);
471 return 0;
472 }
473 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
474
_snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream * substream,size_t size,gfp_t gfp_flags)475 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
476 size_t size, gfp_t gfp_flags)
477 {
478 struct snd_pcm_runtime *runtime;
479
480 if (PCM_RUNTIME_CHECK(substream))
481 return -EINVAL;
482 runtime = substream->runtime;
483 if (runtime->dma_area) {
484 if (runtime->dma_bytes >= size)
485 return 0; /* already large enough */
486 vfree(runtime->dma_area);
487 }
488 runtime->dma_area = __vmalloc(size, gfp_flags);
489 if (!runtime->dma_area)
490 return -ENOMEM;
491 runtime->dma_bytes = size;
492 return 1;
493 }
494 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
495
496 /**
497 * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
498 * @substream: the substream with a buffer allocated by
499 * snd_pcm_lib_alloc_vmalloc_buffer()
500 *
501 * Return: Zero if successful, or a negative error code on failure.
502 */
snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream * substream)503 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
504 {
505 struct snd_pcm_runtime *runtime;
506
507 if (PCM_RUNTIME_CHECK(substream))
508 return -EINVAL;
509 runtime = substream->runtime;
510 vfree(runtime->dma_area);
511 runtime->dma_area = NULL;
512 return 0;
513 }
514 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
515
516 /**
517 * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
518 * @substream: the substream with a buffer allocated by
519 * snd_pcm_lib_alloc_vmalloc_buffer()
520 * @offset: offset in the buffer
521 *
522 * This function is to be used as the page callback in the PCM ops.
523 *
524 * Return: The page struct, or %NULL on failure.
525 */
snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream * substream,unsigned long offset)526 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
527 unsigned long offset)
528 {
529 return vmalloc_to_page(substream->runtime->dma_area + offset);
530 }
531 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);
532