xref: /linux/sound/core/pcm_memory.c (revision d91517839e5d95adc0cf4b28caa7af62a71de526)
1 /*
2  *  Digital Audio (PCM) abstract layer
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 #include <asm/io.h>
23 #include <linux/time.h>
24 #include <linux/init.h>
25 #include <linux/slab.h>
26 #include <linux/moduleparam.h>
27 #include <linux/vmalloc.h>
28 #include <linux/export.h>
29 #include <sound/core.h>
30 #include <sound/pcm.h>
31 #include <sound/info.h>
32 #include <sound/initval.h>
33 
34 static int preallocate_dma = 1;
35 module_param(preallocate_dma, int, 0444);
36 MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
37 
38 static int maximum_substreams = 4;
39 module_param(maximum_substreams, int, 0444);
40 MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
41 
42 static const size_t snd_minimum_buffer = 16384;
43 
44 
45 /*
46  * try to allocate as the large pages as possible.
47  * stores the resultant memory size in *res_size.
48  *
49  * the minimum size is snd_minimum_buffer.  it should be power of 2.
50  */
51 static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size)
52 {
53 	struct snd_dma_buffer *dmab = &substream->dma_buffer;
54 	size_t orig_size = size;
55 	int err;
56 
57 	do {
58 		if ((err = snd_dma_alloc_pages(dmab->dev.type, dmab->dev.dev,
59 					       size, dmab)) < 0) {
60 			if (err != -ENOMEM)
61 				return err; /* fatal error */
62 		} else
63 			return 0;
64 		size >>= 1;
65 	} while (size >= snd_minimum_buffer);
66 	dmab->bytes = 0; /* tell error */
67 	pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
68 		substream->pcm->card->number, substream->pcm->device,
69 		substream->stream ? 'c' : 'p', substream->number,
70 		substream->pcm->name, orig_size);
71 	return 0;
72 }
73 
74 /*
75  * release the preallocated buffer if not yet done.
76  */
77 static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
78 {
79 	if (substream->dma_buffer.area == NULL)
80 		return;
81 	snd_dma_free_pages(&substream->dma_buffer);
82 	substream->dma_buffer.area = NULL;
83 }
84 
85 /**
86  * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
87  * @substream: the pcm substream instance
88  *
89  * Releases the pre-allocated buffer of the given substream.
90  *
91  * Return: Zero if successful, or a negative error code on failure.
92  */
93 int snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
94 {
95 	snd_pcm_lib_preallocate_dma_free(substream);
96 #ifdef CONFIG_SND_VERBOSE_PROCFS
97 	snd_info_free_entry(substream->proc_prealloc_max_entry);
98 	substream->proc_prealloc_max_entry = NULL;
99 	snd_info_free_entry(substream->proc_prealloc_entry);
100 	substream->proc_prealloc_entry = NULL;
101 #endif
102 	return 0;
103 }
104 
105 /**
106  * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
107  * @pcm: the pcm instance
108  *
109  * Releases all the pre-allocated buffers on the given pcm.
110  *
111  * Return: Zero if successful, or a negative error code on failure.
112  */
113 int snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
114 {
115 	struct snd_pcm_substream *substream;
116 	int stream;
117 
118 	for (stream = 0; stream < 2; stream++)
119 		for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
120 			snd_pcm_lib_preallocate_free(substream);
121 	return 0;
122 }
123 
124 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
125 
126 #ifdef CONFIG_SND_VERBOSE_PROCFS
127 /*
128  * read callback for prealloc proc file
129  *
130  * prints the current allocated size in kB.
131  */
132 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
133 					      struct snd_info_buffer *buffer)
134 {
135 	struct snd_pcm_substream *substream = entry->private_data;
136 	snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
137 }
138 
139 /*
140  * read callback for prealloc_max proc file
141  *
142  * prints the maximum allowed size in kB.
143  */
144 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
145 						  struct snd_info_buffer *buffer)
146 {
147 	struct snd_pcm_substream *substream = entry->private_data;
148 	snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
149 }
150 
151 /*
152  * write callback for prealloc proc file
153  *
154  * accepts the preallocation size in kB.
155  */
156 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
157 					       struct snd_info_buffer *buffer)
158 {
159 	struct snd_pcm_substream *substream = entry->private_data;
160 	char line[64], str[64];
161 	size_t size;
162 	struct snd_dma_buffer new_dmab;
163 
164 	if (substream->runtime) {
165 		buffer->error = -EBUSY;
166 		return;
167 	}
168 	if (!snd_info_get_line(buffer, line, sizeof(line))) {
169 		snd_info_get_str(str, line, sizeof(str));
170 		size = simple_strtoul(str, NULL, 10) * 1024;
171 		if ((size != 0 && size < 8192) || size > substream->dma_max) {
172 			buffer->error = -EINVAL;
173 			return;
174 		}
175 		if (substream->dma_buffer.bytes == size)
176 			return;
177 		memset(&new_dmab, 0, sizeof(new_dmab));
178 		new_dmab.dev = substream->dma_buffer.dev;
179 		if (size > 0) {
180 			if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
181 						substream->dma_buffer.dev.dev,
182 						size, &new_dmab) < 0) {
183 				buffer->error = -ENOMEM;
184 				return;
185 			}
186 			substream->buffer_bytes_max = size;
187 		} else {
188 			substream->buffer_bytes_max = UINT_MAX;
189 		}
190 		if (substream->dma_buffer.area)
191 			snd_dma_free_pages(&substream->dma_buffer);
192 		substream->dma_buffer = new_dmab;
193 	} else {
194 		buffer->error = -EINVAL;
195 	}
196 }
197 
198 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
199 {
200 	struct snd_info_entry *entry;
201 
202 	if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc", substream->proc_root)) != NULL) {
203 		entry->c.text.read = snd_pcm_lib_preallocate_proc_read;
204 		entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
205 		entry->mode |= S_IWUSR;
206 		entry->private_data = substream;
207 		if (snd_info_register(entry) < 0) {
208 			snd_info_free_entry(entry);
209 			entry = NULL;
210 		}
211 	}
212 	substream->proc_prealloc_entry = entry;
213 	if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max", substream->proc_root)) != NULL) {
214 		entry->c.text.read = snd_pcm_lib_preallocate_max_proc_read;
215 		entry->private_data = substream;
216 		if (snd_info_register(entry) < 0) {
217 			snd_info_free_entry(entry);
218 			entry = NULL;
219 		}
220 	}
221 	substream->proc_prealloc_max_entry = entry;
222 }
223 
224 #else /* !CONFIG_SND_VERBOSE_PROCFS */
225 #define preallocate_info_init(s)
226 #endif /* CONFIG_SND_VERBOSE_PROCFS */
227 
228 /*
229  * pre-allocate the buffer and create a proc file for the substream
230  */
231 static int snd_pcm_lib_preallocate_pages1(struct snd_pcm_substream *substream,
232 					  size_t size, size_t max)
233 {
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 	preallocate_info_init(substream);
242 	return 0;
243 }
244 
245 
246 /**
247  * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
248  * @substream: the pcm substream instance
249  * @type: DMA type (SNDRV_DMA_TYPE_*)
250  * @data: DMA type dependent data
251  * @size: the requested pre-allocation size in bytes
252  * @max: the max. allowed pre-allocation size
253  *
254  * Do pre-allocation for the given DMA buffer type.
255  *
256  * Return: Zero if successful, or a negative error code on failure.
257  */
258 int snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
259 				  int type, struct device *data,
260 				  size_t size, size_t max)
261 {
262 	substream->dma_buffer.dev.type = type;
263 	substream->dma_buffer.dev.dev = data;
264 	return snd_pcm_lib_preallocate_pages1(substream, size, max);
265 }
266 
267 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
268 
269 /**
270  * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
271  * @pcm: the pcm instance
272  * @type: DMA type (SNDRV_DMA_TYPE_*)
273  * @data: DMA type dependent data
274  * @size: the requested pre-allocation size in bytes
275  * @max: the max. allowed pre-allocation size
276  *
277  * Do pre-allocation to all substreams of the given pcm for the
278  * specified DMA type.
279  *
280  * Return: Zero if successful, or a negative error code on failure.
281  */
282 int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
283 					  int type, void *data,
284 					  size_t size, size_t max)
285 {
286 	struct snd_pcm_substream *substream;
287 	int stream, err;
288 
289 	for (stream = 0; stream < 2; stream++)
290 		for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
291 			if ((err = snd_pcm_lib_preallocate_pages(substream, type, data, size, max)) < 0)
292 				return err;
293 	return 0;
294 }
295 
296 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
297 
298 #ifdef CONFIG_SND_DMA_SGBUF
299 /**
300  * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
301  * @substream: the pcm substream instance
302  * @offset: the buffer offset
303  *
304  * Used as the page callback of PCM ops.
305  *
306  * Return: The page struct at the given buffer offset. %NULL on failure.
307  */
308 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
309 {
310 	struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
311 
312 	unsigned int idx = offset >> PAGE_SHIFT;
313 	if (idx >= (unsigned int)sgbuf->pages)
314 		return NULL;
315 	return sgbuf->page_table[idx];
316 }
317 
318 EXPORT_SYMBOL(snd_pcm_sgbuf_ops_page);
319 #endif /* CONFIG_SND_DMA_SGBUF */
320 
321 /**
322  * snd_pcm_lib_malloc_pages - allocate the DMA buffer
323  * @substream: the substream to allocate the DMA buffer to
324  * @size: the requested buffer size in bytes
325  *
326  * Allocates the DMA buffer on the BUS type given earlier to
327  * snd_pcm_lib_preallocate_xxx_pages().
328  *
329  * Return: 1 if the buffer is changed, 0 if not changed, or a negative
330  * code on failure.
331  */
332 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
333 {
334 	struct snd_pcm_runtime *runtime;
335 	struct snd_dma_buffer *dmab = NULL;
336 
337 	if (PCM_RUNTIME_CHECK(substream))
338 		return -EINVAL;
339 	if (snd_BUG_ON(substream->dma_buffer.dev.type ==
340 		       SNDRV_DMA_TYPE_UNKNOWN))
341 		return -EINVAL;
342 	runtime = substream->runtime;
343 
344 	if (runtime->dma_buffer_p) {
345 		/* perphaps, we might free the large DMA memory region
346 		   to save some space here, but the actual solution
347 		   costs us less time */
348 		if (runtime->dma_buffer_p->bytes >= size) {
349 			runtime->dma_bytes = size;
350 			return 0;	/* ok, do not change */
351 		}
352 		snd_pcm_lib_free_pages(substream);
353 	}
354 	if (substream->dma_buffer.area != NULL &&
355 	    substream->dma_buffer.bytes >= size) {
356 		dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
357 	} else {
358 		dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
359 		if (! dmab)
360 			return -ENOMEM;
361 		dmab->dev = substream->dma_buffer.dev;
362 		if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
363 					substream->dma_buffer.dev.dev,
364 					size, dmab) < 0) {
365 			kfree(dmab);
366 			return -ENOMEM;
367 		}
368 	}
369 	snd_pcm_set_runtime_buffer(substream, dmab);
370 	runtime->dma_bytes = size;
371 	return 1;			/* area was changed */
372 }
373 
374 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
375 
376 /**
377  * snd_pcm_lib_free_pages - release the allocated DMA buffer.
378  * @substream: the substream to release the DMA buffer
379  *
380  * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
381  *
382  * Return: Zero if successful, or a negative error code on failure.
383  */
384 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
385 {
386 	struct snd_pcm_runtime *runtime;
387 
388 	if (PCM_RUNTIME_CHECK(substream))
389 		return -EINVAL;
390 	runtime = substream->runtime;
391 	if (runtime->dma_area == NULL)
392 		return 0;
393 	if (runtime->dma_buffer_p != &substream->dma_buffer) {
394 		/* it's a newly allocated buffer.  release it now. */
395 		snd_dma_free_pages(runtime->dma_buffer_p);
396 		kfree(runtime->dma_buffer_p);
397 	}
398 	snd_pcm_set_runtime_buffer(substream, NULL);
399 	return 0;
400 }
401 
402 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
403 
404 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
405 				      size_t size, gfp_t gfp_flags)
406 {
407 	struct snd_pcm_runtime *runtime;
408 
409 	if (PCM_RUNTIME_CHECK(substream))
410 		return -EINVAL;
411 	runtime = substream->runtime;
412 	if (runtime->dma_area) {
413 		if (runtime->dma_bytes >= size)
414 			return 0; /* already large enough */
415 		vfree(runtime->dma_area);
416 	}
417 	runtime->dma_area = __vmalloc(size, gfp_flags, PAGE_KERNEL);
418 	if (!runtime->dma_area)
419 		return -ENOMEM;
420 	runtime->dma_bytes = size;
421 	return 1;
422 }
423 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
424 
425 /**
426  * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
427  * @substream: the substream with a buffer allocated by
428  *	snd_pcm_lib_alloc_vmalloc_buffer()
429  *
430  * Return: Zero if successful, or a negative error code on failure.
431  */
432 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
433 {
434 	struct snd_pcm_runtime *runtime;
435 
436 	if (PCM_RUNTIME_CHECK(substream))
437 		return -EINVAL;
438 	runtime = substream->runtime;
439 	vfree(runtime->dma_area);
440 	runtime->dma_area = NULL;
441 	return 0;
442 }
443 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
444 
445 /**
446  * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
447  * @substream: the substream with a buffer allocated by
448  *	snd_pcm_lib_alloc_vmalloc_buffer()
449  * @offset: offset in the buffer
450  *
451  * This function is to be used as the page callback in the PCM ops.
452  *
453  * Return: The page struct, or %NULL on failure.
454  */
455 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
456 					  unsigned long offset)
457 {
458 	return vmalloc_to_page(substream->runtime->dma_area + offset);
459 }
460 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);
461