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,size_t size,struct snd_dma_buffer * dmab)34 static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
35 size_t size, struct snd_dma_buffer *dmab)
36 {
37 int err;
38
39 if (max_alloc_per_card &&
40 card->total_pcm_alloc_bytes + size > max_alloc_per_card)
41 return -ENOMEM;
42
43 err = snd_dma_alloc_pages(type, dev, size, dmab);
44 if (!err) {
45 mutex_lock(&card->memory_mutex);
46 card->total_pcm_alloc_bytes += dmab->bytes;
47 mutex_unlock(&card->memory_mutex);
48 }
49 return err;
50 }
51
do_free_pages(struct snd_card * card,struct snd_dma_buffer * dmab)52 static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
53 {
54 if (!dmab->area)
55 return;
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);
61 dmab->area = NULL;
62 }
63
64 /*
65 * try to allocate as the large pages as possible.
66 * stores the resultant memory size in *res_size.
67 *
68 * the minimum size is snd_minimum_buffer. it should be power of 2.
69 */
preallocate_pcm_pages(struct snd_pcm_substream * substream,size_t size)70 static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size)
71 {
72 struct snd_dma_buffer *dmab = &substream->dma_buffer;
73 struct snd_card *card = substream->pcm->card;
74 size_t orig_size = size;
75 int err;
76
77 do {
78 err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
79 size, dmab);
80 if (err != -ENOMEM)
81 return err;
82 size >>= 1;
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);
89 return 0;
90 }
91
92 /**
93 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
94 * @substream: the pcm substream instance
95 *
96 * Releases the pre-allocated buffer of the given substream.
97 */
snd_pcm_lib_preallocate_free(struct snd_pcm_substream * substream)98 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
99 {
100 do_free_pages(substream->pcm->card, &substream->dma_buffer);
101 }
102
103 /**
104 * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
105 * @pcm: the pcm instance
106 *
107 * Releases all the pre-allocated buffers on the given pcm.
108 */
snd_pcm_lib_preallocate_free_for_all(struct snd_pcm * pcm)109 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
110 {
111 struct snd_pcm_substream *substream;
112 int stream;
113
114 for_each_pcm_substream(pcm, stream, substream)
115 snd_pcm_lib_preallocate_free(substream);
116 }
117 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
118
119 #ifdef CONFIG_SND_VERBOSE_PROCFS
120 /*
121 * read callback for prealloc proc file
122 *
123 * prints the current allocated size in kB.
124 */
snd_pcm_lib_preallocate_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)125 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
126 struct snd_info_buffer *buffer)
127 {
128 struct snd_pcm_substream *substream = entry->private_data;
129 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
130 }
131
132 /*
133 * read callback for prealloc_max proc file
134 *
135 * prints the maximum allowed size in kB.
136 */
snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)137 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
138 struct snd_info_buffer *buffer)
139 {
140 struct snd_pcm_substream *substream = entry->private_data;
141 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
142 }
143
144 /*
145 * write callback for prealloc proc file
146 *
147 * accepts the preallocation size in kB.
148 */
snd_pcm_lib_preallocate_proc_write(struct snd_info_entry * entry,struct snd_info_buffer * buffer)149 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
150 struct snd_info_buffer *buffer)
151 {
152 struct snd_pcm_substream *substream = entry->private_data;
153 struct snd_card *card = substream->pcm->card;
154 char line[64], str[64];
155 size_t size;
156 struct snd_dma_buffer new_dmab;
157
158 if (substream->runtime) {
159 buffer->error = -EBUSY;
160 return;
161 }
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;
167 return;
168 }
169 if (substream->dma_buffer.bytes == size)
170 return;
171 memset(&new_dmab, 0, sizeof(new_dmab));
172 new_dmab.dev = substream->dma_buffer.dev;
173 if (size > 0) {
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);
183 return;
184 }
185 substream->buffer_bytes_max = size;
186 } else {
187 substream->buffer_bytes_max = UINT_MAX;
188 }
189 if (substream->dma_buffer.area)
190 do_free_pages(card, &substream->dma_buffer);
191 substream->dma_buffer = new_dmab;
192 } else {
193 buffer->error = -EINVAL;
194 }
195 }
196
preallocate_info_init(struct snd_pcm_substream * substream)197 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
198 {
199 struct snd_info_entry *entry;
200
201 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
202 substream->proc_root);
203 if (entry) {
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;
207 entry->mode |= 0200;
208 }
209 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
210 substream->proc_root);
211 if (entry)
212 snd_info_set_text_ops(entry, substream,
213 snd_pcm_lib_preallocate_max_proc_read);
214 }
215
216 #else /* !CONFIG_SND_VERBOSE_PROCFS */
preallocate_info_init(struct snd_pcm_substream * substream)217 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
218 {
219 }
220 #endif /* CONFIG_SND_VERBOSE_PROCFS */
221
222 /*
223 * pre-allocate the buffer and create a proc file for the substream
224 */
preallocate_pages(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max,bool managed)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)
228 {
229 if (snd_BUG_ON(substream->dma_buffer.dev.type))
230 return;
231
232 substream->dma_buffer.dev.type = type;
233 substream->dma_buffer.dev.dev = data;
234
235 if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
236 preallocate_pcm_pages(substream, size);
237
238 if (substream->dma_buffer.bytes > 0)
239 substream->buffer_bytes_max = substream->dma_buffer.bytes;
240 substream->dma_max = max;
241 if (max > 0)
242 preallocate_info_init(substream);
243 if (managed)
244 substream->managed_buffer_alloc = 1;
245 }
246
preallocate_pages_for_all(struct snd_pcm * pcm,int type,void * data,size_t size,size_t max,bool managed)247 static void preallocate_pages_for_all(struct snd_pcm *pcm, int type,
248 void *data, size_t size, size_t max,
249 bool managed)
250 {
251 struct snd_pcm_substream *substream;
252 int stream;
253
254 for_each_pcm_substream(pcm, stream, substream)
255 preallocate_pages(substream, type, data, size, max, managed);
256 }
257
258 /**
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
265 *
266 * Do pre-allocation for the given DMA buffer type.
267 */
snd_pcm_lib_preallocate_pages(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max)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)
271 {
272 preallocate_pages(substream, type, data, size, max, false);
273 }
274 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
275
276 /**
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
283 *
284 * Do pre-allocation to all substreams of the given pcm for the
285 * specified DMA type.
286 */
snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm * pcm,int type,void * data,size_t size,size_t max)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)
290 {
291 preallocate_pages_for_all(pcm, type, data, size, max, false);
292 }
293 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
294
295 /**
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
302 *
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.
312 */
snd_pcm_set_managed_buffer(struct snd_pcm_substream * substream,int type,struct device * data,size_t size,size_t max)313 void snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
314 struct device *data, size_t size, size_t max)
315 {
316 preallocate_pages(substream, type, data, size, max, true);
317 }
318 EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
319
320 /**
321 * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
322 * 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
328 *
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.
331 */
snd_pcm_set_managed_buffer_all(struct snd_pcm * pcm,int type,struct device * data,size_t size,size_t max)332 void snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
333 struct device *data,
334 size_t size, size_t max)
335 {
336 preallocate_pages_for_all(pcm, type, data, size, max, true);
337 }
338 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
339
340 #ifdef CONFIG_SND_DMA_SGBUF
341 /*
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
345 *
346 * Used as the page callback of PCM ops.
347 *
348 * Return: The page struct at the given buffer offset. %NULL on failure.
349 */
snd_pcm_sgbuf_ops_page(struct snd_pcm_substream * substream,unsigned long offset)350 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
351 {
352 struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
353
354 unsigned int idx = offset >> PAGE_SHIFT;
355 if (idx >= (unsigned int)sgbuf->pages)
356 return NULL;
357 return sgbuf->page_table[idx];
358 }
359 #endif /* CONFIG_SND_DMA_SGBUF */
360
361 /**
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
365 *
366 * Allocates the DMA buffer on the BUS type given earlier to
367 * snd_pcm_lib_preallocate_xxx_pages().
368 *
369 * Return: 1 if the buffer is changed, 0 if not changed, or a negative
370 * code on failure.
371 */
snd_pcm_lib_malloc_pages(struct snd_pcm_substream * substream,size_t size)372 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
373 {
374 struct snd_card *card;
375 struct snd_pcm_runtime *runtime;
376 struct snd_dma_buffer *dmab = NULL;
377
378 if (PCM_RUNTIME_CHECK(substream))
379 return -EINVAL;
380 if (snd_BUG_ON(substream->dma_buffer.dev.type ==
381 SNDRV_DMA_TYPE_UNKNOWN))
382 return -EINVAL;
383 runtime = substream->runtime;
384 card = substream->pcm->card;
385
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 */
393 }
394 snd_pcm_lib_free_pages(substream);
395 }
396 if (substream->dma_buffer.area != NULL &&
397 substream->dma_buffer.bytes >= size) {
398 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
399 } else {
400 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
401 if (! dmab)
402 return -ENOMEM;
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,
407 size, dmab) < 0) {
408 kfree(dmab);
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);
413 return -ENOMEM;
414 }
415 }
416 snd_pcm_set_runtime_buffer(substream, dmab);
417 runtime->dma_bytes = size;
418 return 1; /* area was changed */
419 }
420 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
421
422 /**
423 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
424 * @substream: the substream to release the DMA buffer
425 *
426 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
427 *
428 * Return: Zero if successful, or a negative error code on failure.
429 */
snd_pcm_lib_free_pages(struct snd_pcm_substream * substream)430 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
431 {
432 struct snd_card *card = substream->pcm->card;
433 struct snd_pcm_runtime *runtime;
434
435 if (PCM_RUNTIME_CHECK(substream))
436 return -EINVAL;
437 runtime = substream->runtime;
438 if (runtime->dma_area == NULL)
439 return 0;
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);
444 }
445 snd_pcm_set_runtime_buffer(substream, NULL);
446 return 0;
447 }
448 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
449
_snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream * substream,size_t size,gfp_t gfp_flags)450 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
451 size_t size, gfp_t gfp_flags)
452 {
453 struct snd_pcm_runtime *runtime;
454
455 if (PCM_RUNTIME_CHECK(substream))
456 return -EINVAL;
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);
462 }
463 runtime->dma_area = __vmalloc(size, gfp_flags);
464 if (!runtime->dma_area)
465 return -ENOMEM;
466 runtime->dma_bytes = size;
467 return 1;
468 }
469 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
470
471 /**
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()
475 *
476 * Return: Zero if successful, or a negative error code on failure.
477 */
snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream * substream)478 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
479 {
480 struct snd_pcm_runtime *runtime;
481
482 if (PCM_RUNTIME_CHECK(substream))
483 return -EINVAL;
484 runtime = substream->runtime;
485 vfree(runtime->dma_area);
486 runtime->dma_area = NULL;
487 return 0;
488 }
489 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
490
491 /**
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
496 *
497 * This function is to be used as the page callback in the PCM ops.
498 *
499 * Return: The page struct, or %NULL on failure.
500 */
snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream * substream,unsigned long offset)501 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
502 unsigned long offset)
503 {
504 return vmalloc_to_page(substream->runtime->dma_area + offset);
505 }
506 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);
507