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 | |
34 | static void __update_allocated_size(struct snd_card *card, ssize_t bytes) |
35 | { |
36 | card->total_pcm_alloc_bytes += bytes; |
37 | } |
38 | |
39 | static void update_allocated_size(struct snd_card *card, ssize_t bytes) |
40 | { |
41 | guard(mutex)(T: &card->memory_mutex); |
42 | __update_allocated_size(card, bytes); |
43 | } |
44 | |
45 | static void decrease_allocated_size(struct snd_card *card, size_t bytes) |
46 | { |
47 | guard(mutex)(T: &card->memory_mutex); |
48 | WARN_ON(card->total_pcm_alloc_bytes < bytes); |
49 | __update_allocated_size(card, bytes: -(ssize_t)bytes); |
50 | } |
51 | |
52 | static int do_alloc_pages(struct snd_card *card, int type, struct device *dev, |
53 | int str, size_t size, struct snd_dma_buffer *dmab) |
54 | { |
55 | enum dma_data_direction dir; |
56 | int err; |
57 | |
58 | /* check and reserve the requested size */ |
59 | scoped_guard(mutex, &card->memory_mutex) { |
60 | if (max_alloc_per_card && |
61 | card->total_pcm_alloc_bytes + size > max_alloc_per_card) |
62 | return -ENOMEM; |
63 | __update_allocated_size(card, bytes: size); |
64 | } |
65 | |
66 | if (str == SNDRV_PCM_STREAM_PLAYBACK) |
67 | dir = DMA_TO_DEVICE; |
68 | else |
69 | dir = DMA_FROM_DEVICE; |
70 | err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab); |
71 | if (!err) { |
72 | /* the actual allocation size might be bigger than requested, |
73 | * and we need to correct the account |
74 | */ |
75 | if (dmab->bytes != size) |
76 | update_allocated_size(card, bytes: dmab->bytes - size); |
77 | } else { |
78 | /* take back on allocation failure */ |
79 | decrease_allocated_size(card, bytes: size); |
80 | } |
81 | return err; |
82 | } |
83 | |
84 | static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab) |
85 | { |
86 | if (!dmab->area) |
87 | return; |
88 | decrease_allocated_size(card, bytes: dmab->bytes); |
89 | snd_dma_free_pages(dmab); |
90 | dmab->area = NULL; |
91 | } |
92 | |
93 | /* |
94 | * try to allocate as the large pages as possible. |
95 | * stores the resultant memory size in *res_size. |
96 | * |
97 | * the minimum size is snd_minimum_buffer. it should be power of 2. |
98 | */ |
99 | static int preallocate_pcm_pages(struct snd_pcm_substream *substream, |
100 | size_t size, bool no_fallback) |
101 | { |
102 | struct snd_dma_buffer *dmab = &substream->dma_buffer; |
103 | struct snd_card *card = substream->pcm->card; |
104 | size_t orig_size = size; |
105 | int err; |
106 | |
107 | do { |
108 | err = do_alloc_pages(card, type: dmab->dev.type, dev: dmab->dev.dev, |
109 | str: substream->stream, size, dmab); |
110 | if (err != -ENOMEM) |
111 | return err; |
112 | if (no_fallback) |
113 | break; |
114 | size >>= 1; |
115 | } while (size >= snd_minimum_buffer); |
116 | dmab->bytes = 0; /* tell error */ |
117 | pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n" , |
118 | substream->pcm->card->number, substream->pcm->device, |
119 | substream->stream ? 'c' : 'p', substream->number, |
120 | substream->pcm->name, orig_size); |
121 | return -ENOMEM; |
122 | } |
123 | |
124 | /** |
125 | * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream. |
126 | * @substream: the pcm substream instance |
127 | * |
128 | * Releases the pre-allocated buffer of the given substream. |
129 | */ |
130 | void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream) |
131 | { |
132 | do_free_pages(card: substream->pcm->card, dmab: &substream->dma_buffer); |
133 | } |
134 | |
135 | /** |
136 | * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm |
137 | * @pcm: the pcm instance |
138 | * |
139 | * Releases all the pre-allocated buffers on the given pcm. |
140 | */ |
141 | void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm) |
142 | { |
143 | struct snd_pcm_substream *substream; |
144 | int stream; |
145 | |
146 | for_each_pcm_substream(pcm, stream, substream) |
147 | snd_pcm_lib_preallocate_free(substream); |
148 | } |
149 | EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all); |
150 | |
151 | #ifdef CONFIG_SND_VERBOSE_PROCFS |
152 | /* |
153 | * read callback for prealloc proc file |
154 | * |
155 | * prints the current allocated size in kB. |
156 | */ |
157 | static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry, |
158 | struct snd_info_buffer *buffer) |
159 | { |
160 | struct snd_pcm_substream *substream = entry->private_data; |
161 | snd_iprintf(buffer, "%lu\n" , (unsigned long) substream->dma_buffer.bytes / 1024); |
162 | } |
163 | |
164 | /* |
165 | * read callback for prealloc_max proc file |
166 | * |
167 | * prints the maximum allowed size in kB. |
168 | */ |
169 | static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry, |
170 | struct snd_info_buffer *buffer) |
171 | { |
172 | struct snd_pcm_substream *substream = entry->private_data; |
173 | snd_iprintf(buffer, "%lu\n" , (unsigned long) substream->dma_max / 1024); |
174 | } |
175 | |
176 | /* |
177 | * write callback for prealloc proc file |
178 | * |
179 | * accepts the preallocation size in kB. |
180 | */ |
181 | static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry, |
182 | struct snd_info_buffer *buffer) |
183 | { |
184 | struct snd_pcm_substream *substream = entry->private_data; |
185 | struct snd_card *card = substream->pcm->card; |
186 | char line[64], str[64]; |
187 | size_t size; |
188 | struct snd_dma_buffer new_dmab; |
189 | |
190 | guard(mutex)(T: &substream->pcm->open_mutex); |
191 | if (substream->runtime) { |
192 | buffer->error = -EBUSY; |
193 | return; |
194 | } |
195 | if (!snd_info_get_line(buffer, line, len: sizeof(line))) { |
196 | snd_info_get_str(dest: str, src: line, len: sizeof(str)); |
197 | size = simple_strtoul(str, NULL, 10) * 1024; |
198 | if ((size != 0 && size < 8192) || size > substream->dma_max) { |
199 | buffer->error = -EINVAL; |
200 | return; |
201 | } |
202 | if (substream->dma_buffer.bytes == size) |
203 | return; |
204 | memset(&new_dmab, 0, sizeof(new_dmab)); |
205 | new_dmab.dev = substream->dma_buffer.dev; |
206 | if (size > 0) { |
207 | if (do_alloc_pages(card, |
208 | type: substream->dma_buffer.dev.type, |
209 | dev: substream->dma_buffer.dev.dev, |
210 | str: substream->stream, |
211 | size, dmab: &new_dmab) < 0) { |
212 | buffer->error = -ENOMEM; |
213 | pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n" , |
214 | substream->pcm->card->number, substream->pcm->device, |
215 | substream->stream ? 'c' : 'p', substream->number, |
216 | substream->pcm->name, size); |
217 | return; |
218 | } |
219 | substream->buffer_bytes_max = size; |
220 | } else { |
221 | substream->buffer_bytes_max = UINT_MAX; |
222 | } |
223 | if (substream->dma_buffer.area) |
224 | do_free_pages(card, dmab: &substream->dma_buffer); |
225 | substream->dma_buffer = new_dmab; |
226 | } else { |
227 | buffer->error = -EINVAL; |
228 | } |
229 | } |
230 | |
231 | static inline void preallocate_info_init(struct snd_pcm_substream *substream) |
232 | { |
233 | struct snd_info_entry *entry; |
234 | |
235 | entry = snd_info_create_card_entry(card: substream->pcm->card, name: "prealloc" , |
236 | parent: substream->proc_root); |
237 | if (entry) { |
238 | snd_info_set_text_ops(entry, private_data: substream, |
239 | read: snd_pcm_lib_preallocate_proc_read); |
240 | entry->c.text.write = snd_pcm_lib_preallocate_proc_write; |
241 | entry->mode |= 0200; |
242 | } |
243 | entry = snd_info_create_card_entry(card: substream->pcm->card, name: "prealloc_max" , |
244 | parent: substream->proc_root); |
245 | if (entry) |
246 | snd_info_set_text_ops(entry, private_data: substream, |
247 | read: snd_pcm_lib_preallocate_max_proc_read); |
248 | } |
249 | |
250 | #else /* !CONFIG_SND_VERBOSE_PROCFS */ |
251 | static inline void preallocate_info_init(struct snd_pcm_substream *substream) |
252 | { |
253 | } |
254 | #endif /* CONFIG_SND_VERBOSE_PROCFS */ |
255 | |
256 | /* |
257 | * pre-allocate the buffer and create a proc file for the substream |
258 | */ |
259 | static int preallocate_pages(struct snd_pcm_substream *substream, |
260 | int type, struct device *data, |
261 | size_t size, size_t max, bool managed) |
262 | { |
263 | int err; |
264 | |
265 | if (snd_BUG_ON(substream->dma_buffer.dev.type)) |
266 | return -EINVAL; |
267 | |
268 | substream->dma_buffer.dev.type = type; |
269 | substream->dma_buffer.dev.dev = data; |
270 | |
271 | if (size > 0) { |
272 | if (!max) { |
273 | /* no fallback, only also inform -ENOMEM */ |
274 | err = preallocate_pcm_pages(substream, size, no_fallback: true); |
275 | if (err < 0) |
276 | return err; |
277 | } else if (preallocate_dma && |
278 | substream->number < maximum_substreams) { |
279 | err = preallocate_pcm_pages(substream, size, no_fallback: false); |
280 | if (err < 0 && err != -ENOMEM) |
281 | return err; |
282 | } |
283 | } |
284 | |
285 | if (substream->dma_buffer.bytes > 0) |
286 | substream->buffer_bytes_max = substream->dma_buffer.bytes; |
287 | substream->dma_max = max; |
288 | if (max > 0) |
289 | preallocate_info_init(substream); |
290 | if (managed) |
291 | substream->managed_buffer_alloc = 1; |
292 | return 0; |
293 | } |
294 | |
295 | static int preallocate_pages_for_all(struct snd_pcm *pcm, int type, |
296 | void *data, size_t size, size_t max, |
297 | bool managed) |
298 | { |
299 | struct snd_pcm_substream *substream; |
300 | int stream, err; |
301 | |
302 | for_each_pcm_substream(pcm, stream, substream) { |
303 | err = preallocate_pages(substream, type, data, size, max, managed); |
304 | if (err < 0) |
305 | return err; |
306 | } |
307 | return 0; |
308 | } |
309 | |
310 | /** |
311 | * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type |
312 | * @substream: the pcm substream instance |
313 | * @type: DMA type (SNDRV_DMA_TYPE_*) |
314 | * @data: DMA type dependent data |
315 | * @size: the requested pre-allocation size in bytes |
316 | * @max: the max. allowed pre-allocation size |
317 | * |
318 | * Do pre-allocation for the given DMA buffer type. |
319 | */ |
320 | void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream, |
321 | int type, struct device *data, |
322 | size_t size, size_t max) |
323 | { |
324 | preallocate_pages(substream, type, data, size, max, managed: false); |
325 | } |
326 | EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages); |
327 | |
328 | /** |
329 | * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams) |
330 | * @pcm: the pcm instance |
331 | * @type: DMA type (SNDRV_DMA_TYPE_*) |
332 | * @data: DMA type dependent data |
333 | * @size: the requested pre-allocation size in bytes |
334 | * @max: the max. allowed pre-allocation size |
335 | * |
336 | * Do pre-allocation to all substreams of the given pcm for the |
337 | * specified DMA type. |
338 | */ |
339 | void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm, |
340 | int type, void *data, |
341 | size_t size, size_t max) |
342 | { |
343 | preallocate_pages_for_all(pcm, type, data, size, max, managed: false); |
344 | } |
345 | EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all); |
346 | |
347 | /** |
348 | * snd_pcm_set_managed_buffer - set up buffer management for a substream |
349 | * @substream: the pcm substream instance |
350 | * @type: DMA type (SNDRV_DMA_TYPE_*) |
351 | * @data: DMA type dependent data |
352 | * @size: the requested pre-allocation size in bytes |
353 | * @max: the max. allowed pre-allocation size |
354 | * |
355 | * Do pre-allocation for the given DMA buffer type, and set the managed |
356 | * buffer allocation mode to the given substream. |
357 | * In this mode, PCM core will allocate a buffer automatically before PCM |
358 | * hw_params ops call, and release the buffer after PCM hw_free ops call |
359 | * as well, so that the driver doesn't need to invoke the allocation and |
360 | * the release explicitly in its callback. |
361 | * When a buffer is actually allocated before the PCM hw_params call, it |
362 | * turns on the runtime buffer_changed flag for drivers changing their h/w |
363 | * parameters accordingly. |
364 | * |
365 | * When @size is non-zero and @max is zero, this tries to allocate for only |
366 | * the exact buffer size without fallback, and may return -ENOMEM. |
367 | * Otherwise, the function tries to allocate smaller chunks if the allocation |
368 | * fails. This is the behavior of snd_pcm_set_fixed_buffer(). |
369 | * |
370 | * When both @size and @max are zero, the function only sets up the buffer |
371 | * for later dynamic allocations. It's used typically for buffers with |
372 | * SNDRV_DMA_TYPE_VMALLOC type. |
373 | * |
374 | * Upon successful buffer allocation and setup, the function returns 0. |
375 | * |
376 | * Return: zero if successful, or a negative error code |
377 | */ |
378 | int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type, |
379 | struct device *data, size_t size, size_t max) |
380 | { |
381 | return preallocate_pages(substream, type, data, size, max, managed: true); |
382 | } |
383 | EXPORT_SYMBOL(snd_pcm_set_managed_buffer); |
384 | |
385 | /** |
386 | * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams |
387 | * for all substreams |
388 | * @pcm: the pcm instance |
389 | * @type: DMA type (SNDRV_DMA_TYPE_*) |
390 | * @data: DMA type dependent data |
391 | * @size: the requested pre-allocation size in bytes |
392 | * @max: the max. allowed pre-allocation size |
393 | * |
394 | * Do pre-allocation to all substreams of the given pcm for the specified DMA |
395 | * type and size, and set the managed_buffer_alloc flag to each substream. |
396 | * |
397 | * Return: zero if successful, or a negative error code |
398 | */ |
399 | int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type, |
400 | struct device *data, |
401 | size_t size, size_t max) |
402 | { |
403 | return preallocate_pages_for_all(pcm, type, data, size, max, managed: true); |
404 | } |
405 | EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all); |
406 | |
407 | /** |
408 | * snd_pcm_lib_malloc_pages - allocate the DMA buffer |
409 | * @substream: the substream to allocate the DMA buffer to |
410 | * @size: the requested buffer size in bytes |
411 | * |
412 | * Allocates the DMA buffer on the BUS type given earlier to |
413 | * snd_pcm_lib_preallocate_xxx_pages(). |
414 | * |
415 | * Return: 1 if the buffer is changed, 0 if not changed, or a negative |
416 | * code on failure. |
417 | */ |
418 | int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size) |
419 | { |
420 | struct snd_card *card; |
421 | struct snd_pcm_runtime *runtime; |
422 | struct snd_dma_buffer *dmab = NULL; |
423 | |
424 | if (PCM_RUNTIME_CHECK(substream)) |
425 | return -EINVAL; |
426 | if (snd_BUG_ON(substream->dma_buffer.dev.type == |
427 | SNDRV_DMA_TYPE_UNKNOWN)) |
428 | return -EINVAL; |
429 | runtime = substream->runtime; |
430 | card = substream->pcm->card; |
431 | |
432 | if (runtime->dma_buffer_p) { |
433 | /* perphaps, we might free the large DMA memory region |
434 | to save some space here, but the actual solution |
435 | costs us less time */ |
436 | if (runtime->dma_buffer_p->bytes >= size) { |
437 | runtime->dma_bytes = size; |
438 | return 0; /* ok, do not change */ |
439 | } |
440 | snd_pcm_lib_free_pages(substream); |
441 | } |
442 | if (substream->dma_buffer.area != NULL && |
443 | substream->dma_buffer.bytes >= size) { |
444 | dmab = &substream->dma_buffer; /* use the pre-allocated buffer */ |
445 | } else { |
446 | /* dma_max=0 means the fixed size preallocation */ |
447 | if (substream->dma_buffer.area && !substream->dma_max) |
448 | return -ENOMEM; |
449 | dmab = kzalloc(size: sizeof(*dmab), GFP_KERNEL); |
450 | if (! dmab) |
451 | return -ENOMEM; |
452 | dmab->dev = substream->dma_buffer.dev; |
453 | if (do_alloc_pages(card, |
454 | type: substream->dma_buffer.dev.type, |
455 | dev: substream->dma_buffer.dev.dev, |
456 | str: substream->stream, |
457 | size, dmab) < 0) { |
458 | kfree(objp: dmab); |
459 | pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n" , |
460 | substream->pcm->card->number, substream->pcm->device, |
461 | substream->stream ? 'c' : 'p', substream->number, |
462 | substream->pcm->name, size); |
463 | return -ENOMEM; |
464 | } |
465 | } |
466 | snd_pcm_set_runtime_buffer(substream, bufp: dmab); |
467 | runtime->dma_bytes = size; |
468 | return 1; /* area was changed */ |
469 | } |
470 | EXPORT_SYMBOL(snd_pcm_lib_malloc_pages); |
471 | |
472 | /** |
473 | * snd_pcm_lib_free_pages - release the allocated DMA buffer. |
474 | * @substream: the substream to release the DMA buffer |
475 | * |
476 | * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages(). |
477 | * |
478 | * Return: Zero if successful, or a negative error code on failure. |
479 | */ |
480 | int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream) |
481 | { |
482 | struct snd_pcm_runtime *runtime; |
483 | |
484 | if (PCM_RUNTIME_CHECK(substream)) |
485 | return -EINVAL; |
486 | runtime = substream->runtime; |
487 | if (runtime->dma_area == NULL) |
488 | return 0; |
489 | if (runtime->dma_buffer_p != &substream->dma_buffer) { |
490 | struct snd_card *card = substream->pcm->card; |
491 | |
492 | /* it's a newly allocated buffer. release it now. */ |
493 | do_free_pages(card, dmab: runtime->dma_buffer_p); |
494 | kfree(objp: runtime->dma_buffer_p); |
495 | } |
496 | snd_pcm_set_runtime_buffer(substream, NULL); |
497 | return 0; |
498 | } |
499 | EXPORT_SYMBOL(snd_pcm_lib_free_pages); |
500 | |
501 | int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream, |
502 | size_t size, gfp_t gfp_flags) |
503 | { |
504 | struct snd_pcm_runtime *runtime; |
505 | |
506 | if (PCM_RUNTIME_CHECK(substream)) |
507 | return -EINVAL; |
508 | runtime = substream->runtime; |
509 | if (runtime->dma_area) { |
510 | if (runtime->dma_bytes >= size) |
511 | return 0; /* already large enough */ |
512 | vfree(addr: runtime->dma_area); |
513 | } |
514 | runtime->dma_area = __vmalloc(size, gfp_mask: gfp_flags); |
515 | if (!runtime->dma_area) |
516 | return -ENOMEM; |
517 | runtime->dma_bytes = size; |
518 | return 1; |
519 | } |
520 | EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer); |
521 | |
522 | /** |
523 | * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer |
524 | * @substream: the substream with a buffer allocated by |
525 | * snd_pcm_lib_alloc_vmalloc_buffer() |
526 | * |
527 | * Return: Zero if successful, or a negative error code on failure. |
528 | */ |
529 | int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream) |
530 | { |
531 | struct snd_pcm_runtime *runtime; |
532 | |
533 | if (PCM_RUNTIME_CHECK(substream)) |
534 | return -EINVAL; |
535 | runtime = substream->runtime; |
536 | vfree(addr: runtime->dma_area); |
537 | runtime->dma_area = NULL; |
538 | return 0; |
539 | } |
540 | EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer); |
541 | |
542 | /** |
543 | * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct |
544 | * @substream: the substream with a buffer allocated by |
545 | * snd_pcm_lib_alloc_vmalloc_buffer() |
546 | * @offset: offset in the buffer |
547 | * |
548 | * This function is to be used as the page callback in the PCM ops. |
549 | * |
550 | * Return: The page struct, or %NULL on failure. |
551 | */ |
552 | struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream, |
553 | unsigned long offset) |
554 | { |
555 | return vmalloc_to_page(addr: substream->runtime->dma_area + offset); |
556 | } |
557 | EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page); |
558 | |