Root/sound/core/pcm_memory.c

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 <sound/core.h>
29#include <sound/pcm.h>
30#include <sound/info.h>
31#include <sound/initval.h>
32
33static int preallocate_dma = 1;
34module_param(preallocate_dma, int, 0444);
35MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
36
37static int maximum_substreams = 4;
38module_param(maximum_substreams, int, 0444);
39MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
40
41static const size_t snd_minimum_buffer = 16384;
42
43
44/*
45 * try to allocate as the large pages as possible.
46 * stores the resultant memory size in *res_size.
47 *
48 * the minimum size is snd_minimum_buffer. it should be power of 2.
49 */
50static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size)
51{
52    struct snd_dma_buffer *dmab = &substream->dma_buffer;
53    int err;
54
55    /* already reserved? */
56    if (snd_dma_get_reserved_buf(dmab, substream->dma_buf_id) > 0) {
57        if (dmab->bytes >= size)
58            return 0; /* yes */
59        /* no, free the reserved block */
60        snd_dma_free_pages(dmab);
61        dmab->bytes = 0;
62    }
63
64    do {
65        if ((err = snd_dma_alloc_pages(dmab->dev.type, dmab->dev.dev,
66                           size, dmab)) < 0) {
67            if (err != -ENOMEM)
68                return err; /* fatal error */
69        } else
70            return 0;
71        size >>= 1;
72    } while (size >= snd_minimum_buffer);
73    dmab->bytes = 0; /* tell error */
74    return 0;
75}
76
77/*
78 * release the preallocated buffer if not yet done.
79 */
80static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
81{
82    if (substream->dma_buffer.area == NULL)
83        return;
84    if (substream->dma_buf_id)
85        snd_dma_reserve_buf(&substream->dma_buffer, substream->dma_buf_id);
86    else
87        snd_dma_free_pages(&substream->dma_buffer);
88    substream->dma_buffer.area = NULL;
89}
90
91/**
92 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
93 * @substream: the pcm substream instance
94 *
95 * Releases the pre-allocated buffer of the given substream.
96 *
97 * Returns zero if successful, or a negative error code on failure.
98 */
99int snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
100{
101    snd_pcm_lib_preallocate_dma_free(substream);
102#ifdef CONFIG_SND_VERBOSE_PROCFS
103    snd_info_free_entry(substream->proc_prealloc_max_entry);
104    substream->proc_prealloc_max_entry = NULL;
105    snd_info_free_entry(substream->proc_prealloc_entry);
106    substream->proc_prealloc_entry = NULL;
107#endif
108    return 0;
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 *
117 * Returns zero if successful, or a negative error code on failure.
118 */
119int snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
120{
121    struct snd_pcm_substream *substream;
122    int stream;
123
124    for (stream = 0; stream < 2; stream++)
125        for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
126            snd_pcm_lib_preallocate_free(substream);
127    return 0;
128}
129
130EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
131
132#ifdef CONFIG_SND_VERBOSE_PROCFS
133/*
134 * read callback for prealloc proc file
135 *
136 * prints the current allocated size in kB.
137 */
138static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
139                          struct snd_info_buffer *buffer)
140{
141    struct snd_pcm_substream *substream = entry->private_data;
142    snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
143}
144
145/*
146 * read callback for prealloc_max proc file
147 *
148 * prints the maximum allowed size in kB.
149 */
150static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
151                          struct snd_info_buffer *buffer)
152{
153    struct snd_pcm_substream *substream = entry->private_data;
154    snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
155}
156
157/*
158 * write callback for prealloc proc file
159 *
160 * accepts the preallocation size in kB.
161 */
162static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
163                           struct snd_info_buffer *buffer)
164{
165    struct snd_pcm_substream *substream = entry->private_data;
166    char line[64], str[64];
167    size_t size;
168    struct snd_dma_buffer new_dmab;
169
170    if (substream->runtime) {
171        buffer->error = -EBUSY;
172        return;
173    }
174    if (!snd_info_get_line(buffer, line, sizeof(line))) {
175        snd_info_get_str(str, line, sizeof(str));
176        size = simple_strtoul(str, NULL, 10) * 1024;
177        if ((size != 0 && size < 8192) || size > substream->dma_max) {
178            buffer->error = -EINVAL;
179            return;
180        }
181        if (substream->dma_buffer.bytes == size)
182            return;
183        memset(&new_dmab, 0, sizeof(new_dmab));
184        new_dmab.dev = substream->dma_buffer.dev;
185        if (size > 0) {
186            if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
187                        substream->dma_buffer.dev.dev,
188                        size, &new_dmab) < 0) {
189                buffer->error = -ENOMEM;
190                return;
191            }
192            substream->buffer_bytes_max = size;
193        } else {
194            substream->buffer_bytes_max = UINT_MAX;
195        }
196        if (substream->dma_buffer.area)
197            snd_dma_free_pages(&substream->dma_buffer);
198        substream->dma_buffer = new_dmab;
199    } else {
200        buffer->error = -EINVAL;
201    }
202}
203
204static inline void preallocate_info_init(struct snd_pcm_substream *substream)
205{
206    struct snd_info_entry *entry;
207
208    if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc", substream->proc_root)) != NULL) {
209        entry->c.text.read = snd_pcm_lib_preallocate_proc_read;
210        entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
211        entry->mode |= S_IWUSR;
212        entry->private_data = substream;
213        if (snd_info_register(entry) < 0) {
214            snd_info_free_entry(entry);
215            entry = NULL;
216        }
217    }
218    substream->proc_prealloc_entry = entry;
219    if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max", substream->proc_root)) != NULL) {
220        entry->c.text.read = snd_pcm_lib_preallocate_max_proc_read;
221        entry->private_data = substream;
222        if (snd_info_register(entry) < 0) {
223            snd_info_free_entry(entry);
224            entry = NULL;
225        }
226    }
227    substream->proc_prealloc_max_entry = entry;
228}
229
230#else /* !CONFIG_SND_VERBOSE_PROCFS */
231#define preallocate_info_init(s)
232#endif /* CONFIG_SND_VERBOSE_PROCFS */
233
234/*
235 * pre-allocate the buffer and create a proc file for the substream
236 */
237static int snd_pcm_lib_preallocate_pages1(struct snd_pcm_substream *substream,
238                      size_t size, size_t max)
239{
240
241    if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
242        preallocate_pcm_pages(substream, size);
243
244    if (substream->dma_buffer.bytes > 0)
245        substream->buffer_bytes_max = substream->dma_buffer.bytes;
246    substream->dma_max = max;
247    preallocate_info_init(substream);
248    return 0;
249}
250
251
252/**
253 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
254 * @substream: the pcm substream instance
255 * @type: DMA type (SNDRV_DMA_TYPE_*)
256 * @data: DMA type dependent data
257 * @size: the requested pre-allocation size in bytes
258 * @max: the max. allowed pre-allocation size
259 *
260 * Do pre-allocation for the given DMA buffer type.
261 *
262 * When substream->dma_buf_id is set, the function tries to look for
263 * the reserved buffer, and the buffer is not freed but reserved at
264 * destruction time. The dma_buf_id must be unique for all systems
265 * (in the same DMA buffer type) e.g. using snd_dma_pci_buf_id().
266 *
267 * Returns zero if successful, or a negative error code on failure.
268 */
269int snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
270                  int type, struct device *data,
271                  size_t size, size_t max)
272{
273    substream->dma_buffer.dev.type = type;
274    substream->dma_buffer.dev.dev = data;
275    return snd_pcm_lib_preallocate_pages1(substream, size, max);
276}
277
278EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
279
280/**
281 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
282 * @pcm: the pcm instance
283 * @type: DMA type (SNDRV_DMA_TYPE_*)
284 * @data: DMA type dependent data
285 * @size: the requested pre-allocation size in bytes
286 * @max: the max. allowed pre-allocation size
287 *
288 * Do pre-allocation to all substreams of the given pcm for the
289 * specified DMA type.
290 *
291 * Returns zero if successful, or a negative error code on failure.
292 */
293int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
294                      int type, void *data,
295                      size_t size, size_t max)
296{
297    struct snd_pcm_substream *substream;
298    int stream, err;
299
300    for (stream = 0; stream < 2; stream++)
301        for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
302            if ((err = snd_pcm_lib_preallocate_pages(substream, type, data, size, max)) < 0)
303                return err;
304    return 0;
305}
306
307EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
308
309#ifdef CONFIG_SND_DMA_SGBUF
310/**
311 * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
312 * @substream: the pcm substream instance
313 * @offset: the buffer offset
314 *
315 * Returns the page struct at the given buffer offset.
316 * Used as the page callback of PCM ops.
317 */
318struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
319{
320    struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
321
322    unsigned int idx = offset >> PAGE_SHIFT;
323    if (idx >= (unsigned int)sgbuf->pages)
324        return NULL;
325    return sgbuf->page_table[idx];
326}
327
328EXPORT_SYMBOL(snd_pcm_sgbuf_ops_page);
329
330/*
331 * compute the max chunk size with continuous pages on sg-buffer
332 */
333unsigned int snd_pcm_sgbuf_get_chunk_size(struct snd_pcm_substream *substream,
334                      unsigned int ofs, unsigned int size)
335{
336    struct snd_sg_buf *sg = snd_pcm_substream_sgbuf(substream);
337    unsigned int start, end, pg;
338
339    start = ofs >> PAGE_SHIFT;
340    end = (ofs + size - 1) >> PAGE_SHIFT;
341    /* check page continuity */
342    pg = sg->table[start].addr >> PAGE_SHIFT;
343    for (;;) {
344        start++;
345        if (start > end)
346            break;
347        pg++;
348        if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
349            return (start << PAGE_SHIFT) - ofs;
350    }
351    /* ok, all on continuous pages */
352    return size;
353}
354EXPORT_SYMBOL(snd_pcm_sgbuf_get_chunk_size);
355#endif /* CONFIG_SND_DMA_SGBUF */
356
357/**
358 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
359 * @substream: the substream to allocate the DMA buffer to
360 * @size: the requested buffer size in bytes
361 *
362 * Allocates the DMA buffer on the BUS type given earlier to
363 * snd_pcm_lib_preallocate_xxx_pages().
364 *
365 * Returns 1 if the buffer is changed, 0 if not changed, or a negative
366 * code on failure.
367 */
368int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
369{
370    struct snd_pcm_runtime *runtime;
371    struct snd_dma_buffer *dmab = NULL;
372
373    if (PCM_RUNTIME_CHECK(substream))
374        return -EINVAL;
375    if (snd_BUG_ON(substream->dma_buffer.dev.type ==
376               SNDRV_DMA_TYPE_UNKNOWN))
377        return -EINVAL;
378    runtime = substream->runtime;
379
380    if (runtime->dma_buffer_p) {
381        /* perphaps, we might free the large DMA memory region
382           to save some space here, but the actual solution
383           costs us less time */
384        if (runtime->dma_buffer_p->bytes >= size) {
385            runtime->dma_bytes = size;
386            return 0; /* ok, do not change */
387        }
388        snd_pcm_lib_free_pages(substream);
389    }
390    if (substream->dma_buffer.area != NULL &&
391        substream->dma_buffer.bytes >= size) {
392        dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
393    } else {
394        dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
395        if (! dmab)
396            return -ENOMEM;
397        dmab->dev = substream->dma_buffer.dev;
398        if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
399                    substream->dma_buffer.dev.dev,
400                    size, dmab) < 0) {
401            kfree(dmab);
402            return -ENOMEM;
403        }
404    }
405    snd_pcm_set_runtime_buffer(substream, dmab);
406    runtime->dma_bytes = size;
407    return 1; /* area was changed */
408}
409
410EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
411
412/**
413 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
414 * @substream: the substream to release the DMA buffer
415 *
416 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
417 *
418 * Returns zero if successful, or a negative error code on failure.
419 */
420int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
421{
422    struct snd_pcm_runtime *runtime;
423
424    if (PCM_RUNTIME_CHECK(substream))
425        return -EINVAL;
426    runtime = substream->runtime;
427    if (runtime->dma_area == NULL)
428        return 0;
429    if (runtime->dma_buffer_p != &substream->dma_buffer) {
430        /* it's a newly allocated buffer. release it now. */
431        snd_dma_free_pages(runtime->dma_buffer_p);
432        kfree(runtime->dma_buffer_p);
433    }
434    snd_pcm_set_runtime_buffer(substream, NULL);
435    return 0;
436}
437
438EXPORT_SYMBOL(snd_pcm_lib_free_pages);
439
440int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
441                      size_t size, gfp_t gfp_flags)
442{
443    struct snd_pcm_runtime *runtime;
444
445    if (PCM_RUNTIME_CHECK(substream))
446        return -EINVAL;
447    runtime = substream->runtime;
448    if (runtime->dma_area) {
449        if (runtime->dma_bytes >= size)
450            return 0; /* already large enough */
451        vfree(runtime->dma_area);
452    }
453    runtime->dma_area = __vmalloc(size, gfp_flags, PAGE_KERNEL);
454    if (!runtime->dma_area)
455        return -ENOMEM;
456    runtime->dma_bytes = size;
457    return 1;
458}
459EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
460
461/**
462 * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
463 * @substream: the substream with a buffer allocated by
464 * snd_pcm_lib_alloc_vmalloc_buffer()
465 */
466int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
467{
468    struct snd_pcm_runtime *runtime;
469
470    if (PCM_RUNTIME_CHECK(substream))
471        return -EINVAL;
472    runtime = substream->runtime;
473    vfree(runtime->dma_area);
474    runtime->dma_area = NULL;
475    return 0;
476}
477EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
478
479/**
480 * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
481 * @substream: the substream with a buffer allocated by
482 * snd_pcm_lib_alloc_vmalloc_buffer()
483 * @offset: offset in the buffer
484 *
485 * This function is to be used as the page callback in the PCM ops.
486 */
487struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
488                      unsigned long offset)
489{
490    return vmalloc_to_page(substream->runtime->dma_area + offset);
491}
492EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);
493

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