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>
19 static int preallocate_dma = 1;
20 module_param(preallocate_dma, int, 0444);
21 MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
23 static int maximum_substreams = 4;
24 module_param(maximum_substreams, int, 0444);
25 MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
27 static const size_t snd_minimum_buffer = 16384;
31 * try to allocate as the large pages as possible.
32 * stores the resultant memory size in *res_size.
34 * the minimum size is snd_minimum_buffer. it should be power of 2.
36 static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size)
38 struct snd_dma_buffer *dmab = &substream->dma_buffer;
39 size_t orig_size = size;
43 if ((err = snd_dma_alloc_pages(dmab->dev.type, dmab->dev.dev,
46 return err; /* fatal error */
50 } while (size >= snd_minimum_buffer);
51 dmab->bytes = 0; /* tell error */
52 pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
53 substream->pcm->card->number, substream->pcm->device,
54 substream->stream ? 'c' : 'p', substream->number,
55 substream->pcm->name, orig_size);
60 * release the preallocated buffer if not yet done.
62 static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
64 if (substream->dma_buffer.area == NULL)
66 snd_dma_free_pages(&substream->dma_buffer);
67 substream->dma_buffer.area = NULL;
71 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
72 * @substream: the pcm substream instance
74 * Releases the pre-allocated buffer of the given substream.
76 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
78 snd_pcm_lib_preallocate_dma_free(substream);
82 * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
83 * @pcm: the pcm instance
85 * Releases all the pre-allocated buffers on the given pcm.
87 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
89 struct snd_pcm_substream *substream;
92 for (stream = 0; stream < 2; stream++)
93 for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
94 snd_pcm_lib_preallocate_free(substream);
96 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
98 #ifdef CONFIG_SND_VERBOSE_PROCFS
100 * read callback for prealloc proc file
102 * prints the current allocated size in kB.
104 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
105 struct snd_info_buffer *buffer)
107 struct snd_pcm_substream *substream = entry->private_data;
108 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
112 * read callback for prealloc_max proc file
114 * prints the maximum allowed size in kB.
116 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
117 struct snd_info_buffer *buffer)
119 struct snd_pcm_substream *substream = entry->private_data;
120 snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
124 * write callback for prealloc proc file
126 * accepts the preallocation size in kB.
128 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
129 struct snd_info_buffer *buffer)
131 struct snd_pcm_substream *substream = entry->private_data;
132 char line[64], str[64];
134 struct snd_dma_buffer new_dmab;
136 if (substream->runtime) {
137 buffer->error = -EBUSY;
140 if (!snd_info_get_line(buffer, line, sizeof(line))) {
141 snd_info_get_str(str, line, sizeof(str));
142 size = simple_strtoul(str, NULL, 10) * 1024;
143 if ((size != 0 && size < 8192) || size > substream->dma_max) {
144 buffer->error = -EINVAL;
147 if (substream->dma_buffer.bytes == size)
149 memset(&new_dmab, 0, sizeof(new_dmab));
150 new_dmab.dev = substream->dma_buffer.dev;
152 if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
153 substream->dma_buffer.dev.dev,
154 size, &new_dmab) < 0) {
155 buffer->error = -ENOMEM;
158 substream->buffer_bytes_max = size;
160 substream->buffer_bytes_max = UINT_MAX;
162 if (substream->dma_buffer.area)
163 snd_dma_free_pages(&substream->dma_buffer);
164 substream->dma_buffer = new_dmab;
166 buffer->error = -EINVAL;
170 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
172 struct snd_info_entry *entry;
174 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
175 substream->proc_root);
177 snd_info_set_text_ops(entry, substream,
178 snd_pcm_lib_preallocate_proc_read);
179 entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
182 entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
183 substream->proc_root);
185 snd_info_set_text_ops(entry, substream,
186 snd_pcm_lib_preallocate_max_proc_read);
189 #else /* !CONFIG_SND_VERBOSE_PROCFS */
190 #define preallocate_info_init(s)
191 #endif /* CONFIG_SND_VERBOSE_PROCFS */
194 * pre-allocate the buffer and create a proc file for the substream
196 static void snd_pcm_lib_preallocate_pages1(struct snd_pcm_substream *substream,
197 size_t size, size_t max)
200 if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
201 preallocate_pcm_pages(substream, size);
203 if (substream->dma_buffer.bytes > 0)
204 substream->buffer_bytes_max = substream->dma_buffer.bytes;
205 substream->dma_max = max;
207 preallocate_info_init(substream);
212 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
213 * @substream: the pcm substream instance
214 * @type: DMA type (SNDRV_DMA_TYPE_*)
215 * @data: DMA type dependent data
216 * @size: the requested pre-allocation size in bytes
217 * @max: the max. allowed pre-allocation size
219 * Do pre-allocation for the given DMA buffer type.
221 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
222 int type, struct device *data,
223 size_t size, size_t max)
225 if (snd_BUG_ON(substream->dma_buffer.dev.type))
227 substream->dma_buffer.dev.type = type;
228 substream->dma_buffer.dev.dev = data;
229 snd_pcm_lib_preallocate_pages1(substream, size, max);
231 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
234 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
235 * @pcm: the pcm instance
236 * @type: DMA type (SNDRV_DMA_TYPE_*)
237 * @data: DMA type dependent data
238 * @size: the requested pre-allocation size in bytes
239 * @max: the max. allowed pre-allocation size
241 * Do pre-allocation to all substreams of the given pcm for the
242 * specified DMA type.
244 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
245 int type, void *data,
246 size_t size, size_t max)
248 struct snd_pcm_substream *substream;
251 for (stream = 0; stream < 2; stream++)
252 for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
253 snd_pcm_lib_preallocate_pages(substream, type, data, size, max);
255 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
257 #ifdef CONFIG_SND_DMA_SGBUF
259 * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
260 * @substream: the pcm substream instance
261 * @offset: the buffer offset
263 * Used as the page callback of PCM ops.
265 * Return: The page struct at the given buffer offset. %NULL on failure.
267 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
269 struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
271 unsigned int idx = offset >> PAGE_SHIFT;
272 if (idx >= (unsigned int)sgbuf->pages)
274 return sgbuf->page_table[idx];
276 #endif /* CONFIG_SND_DMA_SGBUF */
279 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
280 * @substream: the substream to allocate the DMA buffer to
281 * @size: the requested buffer size in bytes
283 * Allocates the DMA buffer on the BUS type given earlier to
284 * snd_pcm_lib_preallocate_xxx_pages().
286 * Return: 1 if the buffer is changed, 0 if not changed, or a negative
289 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
291 struct snd_pcm_runtime *runtime;
292 struct snd_dma_buffer *dmab = NULL;
294 if (PCM_RUNTIME_CHECK(substream))
296 if (snd_BUG_ON(substream->dma_buffer.dev.type ==
297 SNDRV_DMA_TYPE_UNKNOWN))
299 runtime = substream->runtime;
301 if (runtime->dma_buffer_p) {
302 /* perphaps, we might free the large DMA memory region
303 to save some space here, but the actual solution
304 costs us less time */
305 if (runtime->dma_buffer_p->bytes >= size) {
306 runtime->dma_bytes = size;
307 return 0; /* ok, do not change */
309 snd_pcm_lib_free_pages(substream);
311 if (substream->dma_buffer.area != NULL &&
312 substream->dma_buffer.bytes >= size) {
313 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
315 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
318 dmab->dev = substream->dma_buffer.dev;
319 if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
320 substream->dma_buffer.dev.dev,
326 snd_pcm_set_runtime_buffer(substream, dmab);
327 runtime->dma_bytes = size;
328 return 1; /* area was changed */
330 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
333 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
334 * @substream: the substream to release the DMA buffer
336 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
338 * Return: Zero if successful, or a negative error code on failure.
340 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
342 struct snd_pcm_runtime *runtime;
344 if (PCM_RUNTIME_CHECK(substream))
346 runtime = substream->runtime;
347 if (runtime->dma_area == NULL)
349 if (runtime->dma_buffer_p != &substream->dma_buffer) {
350 /* it's a newly allocated buffer. release it now. */
351 snd_dma_free_pages(runtime->dma_buffer_p);
352 kfree(runtime->dma_buffer_p);
354 snd_pcm_set_runtime_buffer(substream, NULL);
357 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
359 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
360 size_t size, gfp_t gfp_flags)
362 struct snd_pcm_runtime *runtime;
364 if (PCM_RUNTIME_CHECK(substream))
366 runtime = substream->runtime;
367 if (runtime->dma_area) {
368 if (runtime->dma_bytes >= size)
369 return 0; /* already large enough */
370 vfree(runtime->dma_area);
372 runtime->dma_area = __vmalloc(size, gfp_flags, PAGE_KERNEL);
373 if (!runtime->dma_area)
375 runtime->dma_bytes = size;
378 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
381 * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
382 * @substream: the substream with a buffer allocated by
383 * snd_pcm_lib_alloc_vmalloc_buffer()
385 * Return: Zero if successful, or a negative error code on failure.
387 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
389 struct snd_pcm_runtime *runtime;
391 if (PCM_RUNTIME_CHECK(substream))
393 runtime = substream->runtime;
394 vfree(runtime->dma_area);
395 runtime->dma_area = NULL;
398 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
401 * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
402 * @substream: the substream with a buffer allocated by
403 * snd_pcm_lib_alloc_vmalloc_buffer()
404 * @offset: offset in the buffer
406 * This function is to be used as the page callback in the PCM ops.
408 * Return: The page struct, or %NULL on failure.
410 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
411 unsigned long offset)
413 return vmalloc_to_page(substream->runtime->dma_area + offset);
415 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);