linux/sound/core/pcm_memory.c
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   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/moduleparam.h>
  26#include <sound/core.h>
  27#include <sound/pcm.h>
  28#include <sound/info.h>
  29#include <sound/initval.h>
  30
  31static int preallocate_dma = 1;
  32module_param(preallocate_dma, int, 0444);
  33MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
  34
  35static int maximum_substreams = 4;
  36module_param(maximum_substreams, int, 0444);
  37MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
  38
  39static const size_t snd_minimum_buffer = 16384;
  40
  41
  42/*
  43 * try to allocate as the large pages as possible.
  44 * stores the resultant memory size in *res_size.
  45 *
  46 * the minimum size is snd_minimum_buffer.  it should be power of 2.
  47 */
  48static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size)
  49{
  50        struct snd_dma_buffer *dmab = &substream->dma_buffer;
  51        int err;
  52
  53        /* already reserved? */
  54        if (snd_dma_get_reserved_buf(dmab, substream->dma_buf_id) > 0) {
  55                if (dmab->bytes >= size)
  56                        return 0; /* yes */
  57                /* no, free the reserved block */
  58                snd_dma_free_pages(dmab);
  59                dmab->bytes = 0;
  60        }
  61
  62        do {
  63                if ((err = snd_dma_alloc_pages(dmab->dev.type, dmab->dev.dev,
  64                                               size, dmab)) < 0) {
  65                        if (err != -ENOMEM)
  66                                return err; /* fatal error */
  67                } else
  68                        return 0;
  69                size >>= 1;
  70        } while (size >= snd_minimum_buffer);
  71        dmab->bytes = 0; /* tell error */
  72        return 0;
  73}
  74
  75/*
  76 * release the preallocated buffer if not yet done.
  77 */
  78static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
  79{
  80        if (substream->dma_buffer.area == NULL)
  81                return;
  82        if (substream->dma_buf_id)
  83                snd_dma_reserve_buf(&substream->dma_buffer, substream->dma_buf_id);
  84        else
  85                snd_dma_free_pages(&substream->dma_buffer);
  86        substream->dma_buffer.area = NULL;
  87}
  88
  89/**
  90 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
  91 * @substream: the pcm substream instance
  92 *
  93 * Releases the pre-allocated buffer of the given substream.
  94 *
  95 * Returns zero if successful, or a negative error code on failure.
  96 */
  97int snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
  98{
  99        snd_pcm_lib_preallocate_dma_free(substream);
 100#ifdef CONFIG_SND_VERBOSE_PROCFS
 101        snd_info_free_entry(substream->proc_prealloc_max_entry);
 102        substream->proc_prealloc_max_entry = NULL;
 103        snd_info_free_entry(substream->proc_prealloc_entry);
 104        substream->proc_prealloc_entry = NULL;
 105#endif
 106        return 0;
 107}
 108
 109/**
 110 * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
 111 * @pcm: the pcm instance
 112 *
 113 * Releases all the pre-allocated buffers on the given pcm.
 114 *
 115 * Returns zero if successful, or a negative error code on failure.
 116 */
 117int snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
 118{
 119        struct snd_pcm_substream *substream;
 120        int stream;
 121
 122        for (stream = 0; stream < 2; stream++)
 123                for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
 124                        snd_pcm_lib_preallocate_free(substream);
 125        return 0;
 126}
 127
 128EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
 129
 130#ifdef CONFIG_SND_VERBOSE_PROCFS
 131/*
 132 * read callback for prealloc proc file
 133 *
 134 * prints the current allocated size in kB.
 135 */
 136static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
 137                                              struct snd_info_buffer *buffer)
 138{
 139        struct snd_pcm_substream *substream = entry->private_data;
 140        snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
 141}
 142
 143/*
 144 * read callback for prealloc_max proc file
 145 *
 146 * prints the maximum allowed size in kB.
 147 */
 148static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
 149                                                  struct snd_info_buffer *buffer)
 150{
 151        struct snd_pcm_substream *substream = entry->private_data;
 152        snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
 153}
 154
 155/*
 156 * write callback for prealloc proc file
 157 *
 158 * accepts the preallocation size in kB.
 159 */
 160static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
 161                                               struct snd_info_buffer *buffer)
 162{
 163        struct snd_pcm_substream *substream = entry->private_data;
 164        char line[64], str[64];
 165        size_t size;
 166        struct snd_dma_buffer new_dmab;
 167
 168        if (substream->runtime) {
 169                buffer->error = -EBUSY;
 170                return;
 171        }
 172        if (!snd_info_get_line(buffer, line, sizeof(line))) {
 173                snd_info_get_str(str, line, sizeof(str));
 174                size = simple_strtoul(str, NULL, 10) * 1024;
 175                if ((size != 0 && size < 8192) || size > substream->dma_max) {
 176                        buffer->error = -EINVAL;
 177                        return;
 178                }
 179                if (substream->dma_buffer.bytes == size)
 180                        return;
 181                memset(&new_dmab, 0, sizeof(new_dmab));
 182                new_dmab.dev = substream->dma_buffer.dev;
 183                if (size > 0) {
 184                        if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
 185                                                substream->dma_buffer.dev.dev,
 186                                                size, &new_dmab) < 0) {
 187                                buffer->error = -ENOMEM;
 188                                return;
 189                        }
 190                        substream->buffer_bytes_max = size;
 191                } else {
 192                        substream->buffer_bytes_max = UINT_MAX;
 193                }
 194                if (substream->dma_buffer.area)
 195                        snd_dma_free_pages(&substream->dma_buffer);
 196                substream->dma_buffer = new_dmab;
 197        } else {
 198                buffer->error = -EINVAL;
 199        }
 200}
 201
 202static inline void preallocate_info_init(struct snd_pcm_substream *substream)
 203{
 204        struct snd_info_entry *entry;
 205
 206        if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc", substream->proc_root)) != NULL) {
 207                entry->c.text.read = snd_pcm_lib_preallocate_proc_read;
 208                entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
 209                entry->mode |= S_IWUSR;
 210                entry->private_data = substream;
 211                if (snd_info_register(entry) < 0) {
 212                        snd_info_free_entry(entry);
 213                        entry = NULL;
 214                }
 215        }
 216        substream->proc_prealloc_entry = entry;
 217        if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max", substream->proc_root)) != NULL) {
 218                entry->c.text.read = snd_pcm_lib_preallocate_max_proc_read;
 219                entry->private_data = substream;
 220                if (snd_info_register(entry) < 0) {
 221                        snd_info_free_entry(entry);
 222                        entry = NULL;
 223                }
 224        }
 225        substream->proc_prealloc_max_entry = entry;
 226}
 227
 228#else /* !CONFIG_SND_VERBOSE_PROCFS */
 229#define preallocate_info_init(s)
 230#endif /* CONFIG_SND_VERBOSE_PROCFS */
 231
 232/*
 233 * pre-allocate the buffer and create a proc file for the substream
 234 */
 235static int snd_pcm_lib_preallocate_pages1(struct snd_pcm_substream *substream,
 236                                          size_t size, size_t max)
 237{
 238
 239        if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
 240                preallocate_pcm_pages(substream, size);
 241
 242        if (substream->dma_buffer.bytes > 0)
 243                substream->buffer_bytes_max = substream->dma_buffer.bytes;
 244        substream->dma_max = max;
 245        preallocate_info_init(substream);
 246        return 0;
 247}
 248
 249
 250/**
 251 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
 252 * @substream: the pcm substream instance
 253 * @type: DMA type (SNDRV_DMA_TYPE_*)
 254 * @data: DMA type dependant data
 255 * @size: the requested pre-allocation size in bytes
 256 * @max: the max. allowed pre-allocation size
 257 *
 258 * Do pre-allocation for the given DMA buffer type.
 259 *
 260 * When substream->dma_buf_id is set, the function tries to look for
 261 * the reserved buffer, and the buffer is not freed but reserved at
 262 * destruction time.  The dma_buf_id must be unique for all systems
 263 * (in the same DMA buffer type) e.g. using snd_dma_pci_buf_id().
 264 *
 265 * Returns zero if successful, or a negative error code on failure.
 266 */
 267int snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
 268                                  int type, struct device *data,
 269                                  size_t size, size_t max)
 270{
 271        substream->dma_buffer.dev.type = type;
 272        substream->dma_buffer.dev.dev = data;
 273        return snd_pcm_lib_preallocate_pages1(substream, size, max);
 274}
 275
 276EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
 277
 278/**
 279 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continous memory type (all substreams)
 280 * @pcm: the pcm instance
 281 * @type: DMA type (SNDRV_DMA_TYPE_*)
 282 * @data: DMA type dependant data
 283 * @size: the requested pre-allocation size in bytes
 284 * @max: the max. allowed pre-allocation size
 285 *
 286 * Do pre-allocation to all substreams of the given pcm for the
 287 * specified DMA type.
 288 *
 289 * Returns zero if successful, or a negative error code on failure.
 290 */
 291int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
 292                                          int type, void *data,
 293                                          size_t size, size_t max)
 294{
 295        struct snd_pcm_substream *substream;
 296        int stream, err;
 297
 298        for (stream = 0; stream < 2; stream++)
 299                for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
 300                        if ((err = snd_pcm_lib_preallocate_pages(substream, type, data, size, max)) < 0)
 301                                return err;
 302        return 0;
 303}
 304
 305EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
 306
 307/**
 308 * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
 309 * @substream: the pcm substream instance
 310 * @offset: the buffer offset
 311 *
 312 * Returns the page struct at the given buffer offset.
 313 * Used as the page callback of PCM ops.
 314 */
 315struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
 316{
 317        struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
 318
 319        unsigned int idx = offset >> PAGE_SHIFT;
 320        if (idx >= (unsigned int)sgbuf->pages)
 321                return NULL;
 322        return sgbuf->page_table[idx];
 323}
 324
 325EXPORT_SYMBOL(snd_pcm_sgbuf_ops_page);
 326
 327/*
 328 * compute the max chunk size with continuous pages on sg-buffer
 329 */
 330unsigned int snd_pcm_sgbuf_get_chunk_size(struct snd_pcm_substream *substream,
 331                                          unsigned int ofs, unsigned int size)
 332{
 333        struct snd_sg_buf *sg = snd_pcm_substream_sgbuf(substream);
 334        unsigned int start, end, pg;
 335
 336        start = ofs >> PAGE_SHIFT;
 337        end = (ofs + size - 1) >> PAGE_SHIFT;
 338        /* check page continuity */
 339        pg = sg->table[start].addr >> PAGE_SHIFT;
 340        for (;;) {
 341                start++;
 342                if (start > end)
 343                        break;
 344                pg++;
 345                if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
 346                        return (start << PAGE_SHIFT) - ofs;
 347        }
 348        /* ok, all on continuous pages */
 349        return size;
 350}
 351EXPORT_SYMBOL(snd_pcm_sgbuf_get_chunk_size);
 352
 353/**
 354 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
 355 * @substream: the substream to allocate the DMA buffer to
 356 * @size: the requested buffer size in bytes
 357 *
 358 * Allocates the DMA buffer on the BUS type given earlier to
 359 * snd_pcm_lib_preallocate_xxx_pages().
 360 *
 361 * Returns 1 if the buffer is changed, 0 if not changed, or a negative
 362 * code on failure.
 363 */
 364int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
 365{
 366        struct snd_pcm_runtime *runtime;
 367        struct snd_dma_buffer *dmab = NULL;
 368
 369        if (PCM_RUNTIME_CHECK(substream))
 370                return -EINVAL;
 371        if (snd_BUG_ON(substream->dma_buffer.dev.type ==
 372                       SNDRV_DMA_TYPE_UNKNOWN))
 373                return -EINVAL;
 374        runtime = substream->runtime;
 375
 376        if (runtime->dma_buffer_p) {
 377                /* perphaps, we might free the large DMA memory region
 378                   to save some space here, but the actual solution
 379                   costs us less time */
 380                if (runtime->dma_buffer_p->bytes >= size) {
 381                        runtime->dma_bytes = size;
 382                        return 0;       /* ok, do not change */
 383                }
 384                snd_pcm_lib_free_pages(substream);
 385        }
 386        if (substream->dma_buffer.area != NULL &&
 387            substream->dma_buffer.bytes >= size) {
 388                dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
 389        } else {
 390                dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
 391                if (! dmab)
 392                        return -ENOMEM;
 393                dmab->dev = substream->dma_buffer.dev;
 394                if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
 395                                        substream->dma_buffer.dev.dev,
 396                                        size, dmab) < 0) {
 397                        kfree(dmab);
 398                        return -ENOMEM;
 399                }
 400        }
 401        snd_pcm_set_runtime_buffer(substream, dmab);
 402        runtime->dma_bytes = size;
 403        return 1;                       /* area was changed */
 404}
 405
 406EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
 407
 408/**
 409 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
 410 * @substream: the substream to release the DMA buffer
 411 *
 412 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
 413 *
 414 * Returns zero if successful, or a negative error code on failure.
 415 */
 416int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
 417{
 418        struct snd_pcm_runtime *runtime;
 419
 420        if (PCM_RUNTIME_CHECK(substream))
 421                return -EINVAL;
 422        runtime = substream->runtime;
 423        if (runtime->dma_area == NULL)
 424                return 0;
 425        if (runtime->dma_buffer_p != &substream->dma_buffer) {
 426                /* it's a newly allocated buffer.  release it now. */
 427                snd_dma_free_pages(runtime->dma_buffer_p);
 428                kfree(runtime->dma_buffer_p);
 429        }
 430        snd_pcm_set_runtime_buffer(substream, NULL);
 431        return 0;
 432}
 433
 434EXPORT_SYMBOL(snd_pcm_lib_free_pages);
 435