linux/sound/core/pcm_memory.c
<<
>>
Prefs
   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
  20static int preallocate_dma = 1;
  21module_param(preallocate_dma, int, 0444);
  22MODULE_PARM_DESC(preallocate_dma, "Preallocate DMA memory when the PCM devices are initialized.");
  23
  24static int maximum_substreams = 4;
  25module_param(maximum_substreams, int, 0444);
  26MODULE_PARM_DESC(maximum_substreams, "Maximum substreams with preallocated DMA memory.");
  27
  28static const size_t snd_minimum_buffer = 16384;
  29
  30static unsigned long max_alloc_per_card = 32UL * 1024UL * 1024UL;
  31module_param(max_alloc_per_card, ulong, 0644);
  32MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card.");
  33
  34static 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
  52static 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 */
  70static int preallocate_pcm_pages(struct snd_pcm_substream *substream,
  71                                 size_t size, bool no_fallback)
  72{
  73        struct snd_dma_buffer *dmab = &substream->dma_buffer;
  74        struct snd_card *card = substream->pcm->card;
  75        size_t orig_size = size;
  76        int err;
  77
  78        do {
  79                err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
  80                                     size, dmab);
  81                if (err != -ENOMEM)
  82                        return err;
  83                if (no_fallback)
  84                        break;
  85                size >>= 1;
  86        } while (size >= snd_minimum_buffer);
  87        dmab->bytes = 0; /* tell error */
  88        pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
  89                substream->pcm->card->number, substream->pcm->device,
  90                substream->stream ? 'c' : 'p', substream->number,
  91                substream->pcm->name, orig_size);
  92        return -ENOMEM;
  93}
  94
  95/**
  96 * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
  97 * @substream: the pcm substream instance
  98 *
  99 * Releases the pre-allocated buffer of the given substream.
 100 */
 101void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
 102{
 103        do_free_pages(substream->pcm->card, &substream->dma_buffer);
 104}
 105
 106/**
 107 * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
 108 * @pcm: the pcm instance
 109 *
 110 * Releases all the pre-allocated buffers on the given pcm.
 111 */
 112void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
 113{
 114        struct snd_pcm_substream *substream;
 115        int stream;
 116
 117        for_each_pcm_substream(pcm, stream, substream)
 118                snd_pcm_lib_preallocate_free(substream);
 119}
 120EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
 121
 122#ifdef CONFIG_SND_VERBOSE_PROCFS
 123/*
 124 * read callback for prealloc proc file
 125 *
 126 * prints the current allocated size in kB.
 127 */
 128static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
 129                                              struct snd_info_buffer *buffer)
 130{
 131        struct snd_pcm_substream *substream = entry->private_data;
 132        snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
 133}
 134
 135/*
 136 * read callback for prealloc_max proc file
 137 *
 138 * prints the maximum allowed size in kB.
 139 */
 140static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
 141                                                  struct snd_info_buffer *buffer)
 142{
 143        struct snd_pcm_substream *substream = entry->private_data;
 144        snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
 145}
 146
 147/*
 148 * write callback for prealloc proc file
 149 *
 150 * accepts the preallocation size in kB.
 151 */
 152static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
 153                                               struct snd_info_buffer *buffer)
 154{
 155        struct snd_pcm_substream *substream = entry->private_data;
 156        struct snd_card *card = substream->pcm->card;
 157        char line[64], str[64];
 158        size_t size;
 159        struct snd_dma_buffer new_dmab;
 160
 161        if (substream->runtime) {
 162                buffer->error = -EBUSY;
 163                return;
 164        }
 165        if (!snd_info_get_line(buffer, line, sizeof(line))) {
 166                snd_info_get_str(str, line, sizeof(str));
 167                size = simple_strtoul(str, NULL, 10) * 1024;
 168                if ((size != 0 && size < 8192) || size > substream->dma_max) {
 169                        buffer->error = -EINVAL;
 170                        return;
 171                }
 172                if (substream->dma_buffer.bytes == size)
 173                        return;
 174                memset(&new_dmab, 0, sizeof(new_dmab));
 175                new_dmab.dev = substream->dma_buffer.dev;
 176                if (size > 0) {
 177                        if (do_alloc_pages(card,
 178                                           substream->dma_buffer.dev.type,
 179                                           substream->dma_buffer.dev.dev,
 180                                           size, &new_dmab) < 0) {
 181                                buffer->error = -ENOMEM;
 182                                pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
 183                                         substream->pcm->card->number, substream->pcm->device,
 184                                         substream->stream ? 'c' : 'p', substream->number,
 185                                         substream->pcm->name, size);
 186                                return;
 187                        }
 188                        substream->buffer_bytes_max = size;
 189                } else {
 190                        substream->buffer_bytes_max = UINT_MAX;
 191                }
 192                if (substream->dma_buffer.area)
 193                        do_free_pages(card, &substream->dma_buffer);
 194                substream->dma_buffer = new_dmab;
 195        } else {
 196                buffer->error = -EINVAL;
 197        }
 198}
 199
 200static inline void preallocate_info_init(struct snd_pcm_substream *substream)
 201{
 202        struct snd_info_entry *entry;
 203
 204        entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
 205                                           substream->proc_root);
 206        if (entry) {
 207                snd_info_set_text_ops(entry, substream,
 208                                      snd_pcm_lib_preallocate_proc_read);
 209                entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
 210                entry->mode |= 0200;
 211        }
 212        entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
 213                                           substream->proc_root);
 214        if (entry)
 215                snd_info_set_text_ops(entry, substream,
 216                                      snd_pcm_lib_preallocate_max_proc_read);
 217}
 218
 219#else /* !CONFIG_SND_VERBOSE_PROCFS */
 220static inline void preallocate_info_init(struct snd_pcm_substream *substream)
 221{
 222}
 223#endif /* CONFIG_SND_VERBOSE_PROCFS */
 224
 225/*
 226 * pre-allocate the buffer and create a proc file for the substream
 227 */
 228static int preallocate_pages(struct snd_pcm_substream *substream,
 229                              int type, struct device *data,
 230                              size_t size, size_t max, bool managed)
 231{
 232        int err;
 233
 234        if (snd_BUG_ON(substream->dma_buffer.dev.type))
 235                return -EINVAL;
 236
 237        substream->dma_buffer.dev.type = type;
 238        substream->dma_buffer.dev.dev = data;
 239
 240        if (size > 0) {
 241                if (!max) {
 242                        /* no fallback, only also inform -ENOMEM */
 243                        err = preallocate_pcm_pages(substream, size, true);
 244                        if (err < 0)
 245                                return err;
 246                } else if (preallocate_dma &&
 247                           substream->number < maximum_substreams) {
 248                        err = preallocate_pcm_pages(substream, size, false);
 249                        if (err < 0 && err != -ENOMEM)
 250                                return err;
 251                }
 252        }
 253
 254        if (substream->dma_buffer.bytes > 0)
 255                substream->buffer_bytes_max = substream->dma_buffer.bytes;
 256        substream->dma_max = max;
 257        if (max > 0)
 258                preallocate_info_init(substream);
 259        if (managed)
 260                substream->managed_buffer_alloc = 1;
 261        return 0;
 262}
 263
 264static int preallocate_pages_for_all(struct snd_pcm *pcm, int type,
 265                                      void *data, size_t size, size_t max,
 266                                      bool managed)
 267{
 268        struct snd_pcm_substream *substream;
 269        int stream, err;
 270
 271        for_each_pcm_substream(pcm, stream, substream) {
 272                err = preallocate_pages(substream, type, data, size, max, managed);
 273                if (err < 0)
 274                        return err;
 275        }
 276        return 0;
 277}
 278
 279/**
 280 * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
 281 * @substream: the pcm substream instance
 282 * @type: DMA type (SNDRV_DMA_TYPE_*)
 283 * @data: DMA type dependent data
 284 * @size: the requested pre-allocation size in bytes
 285 * @max: the max. allowed pre-allocation size
 286 *
 287 * Do pre-allocation for the given DMA buffer type.
 288 */
 289void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
 290                                  int type, struct device *data,
 291                                  size_t size, size_t max)
 292{
 293        preallocate_pages(substream, type, data, size, max, false);
 294}
 295EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
 296
 297/**
 298 * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
 299 * @pcm: the pcm instance
 300 * @type: DMA type (SNDRV_DMA_TYPE_*)
 301 * @data: DMA type dependent data
 302 * @size: the requested pre-allocation size in bytes
 303 * @max: the max. allowed pre-allocation size
 304 *
 305 * Do pre-allocation to all substreams of the given pcm for the
 306 * specified DMA type.
 307 */
 308void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
 309                                          int type, void *data,
 310                                          size_t size, size_t max)
 311{
 312        preallocate_pages_for_all(pcm, type, data, size, max, false);
 313}
 314EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
 315
 316/**
 317 * snd_pcm_set_managed_buffer - set up buffer management for a substream
 318 * @substream: the pcm substream instance
 319 * @type: DMA type (SNDRV_DMA_TYPE_*)
 320 * @data: DMA type dependent data
 321 * @size: the requested pre-allocation size in bytes
 322 * @max: the max. allowed pre-allocation size
 323 *
 324 * Do pre-allocation for the given DMA buffer type, and set the managed
 325 * buffer allocation mode to the given substream.
 326 * In this mode, PCM core will allocate a buffer automatically before PCM
 327 * hw_params ops call, and release the buffer after PCM hw_free ops call
 328 * as well, so that the driver doesn't need to invoke the allocation and
 329 * the release explicitly in its callback.
 330 * When a buffer is actually allocated before the PCM hw_params call, it
 331 * turns on the runtime buffer_changed flag for drivers changing their h/w
 332 * parameters accordingly.
 333 *
 334 * When @size is non-zero and @max is zero, this tries to allocate for only
 335 * the exact buffer size without fallback, and may return -ENOMEM.
 336 * Otherwise, the function tries to allocate smaller chunks if the allocation
 337 * fails.  This is the behavior of snd_pcm_set_fixed_buffer().
 338 *
 339 * When both @size and @max are zero, the function only sets up the buffer
 340 * for later dynamic allocations. It's used typically for buffers with
 341 * SNDRV_DMA_TYPE_VMALLOC type.
 342 *
 343 * Upon successful buffer allocation and setup, the function returns 0.
 344 */
 345int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
 346                                struct device *data, size_t size, size_t max)
 347{
 348        return preallocate_pages(substream, type, data, size, max, true);
 349}
 350EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
 351
 352/**
 353 * snd_pcm_set_managed_buffer_all - set up buffer management for all substreams
 354 *      for all substreams
 355 * @pcm: the pcm instance
 356 * @type: DMA type (SNDRV_DMA_TYPE_*)
 357 * @data: DMA type dependent data
 358 * @size: the requested pre-allocation size in bytes
 359 * @max: the max. allowed pre-allocation size
 360 *
 361 * Do pre-allocation to all substreams of the given pcm for the specified DMA
 362 * type and size, and set the managed_buffer_alloc flag to each substream.
 363 */
 364int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
 365                                   struct device *data,
 366                                   size_t size, size_t max)
 367{
 368        return preallocate_pages_for_all(pcm, type, data, size, max, true);
 369}
 370EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
 371
 372/**
 373 * snd_pcm_lib_malloc_pages - allocate the DMA buffer
 374 * @substream: the substream to allocate the DMA buffer to
 375 * @size: the requested buffer size in bytes
 376 *
 377 * Allocates the DMA buffer on the BUS type given earlier to
 378 * snd_pcm_lib_preallocate_xxx_pages().
 379 *
 380 * Return: 1 if the buffer is changed, 0 if not changed, or a negative
 381 * code on failure.
 382 */
 383int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
 384{
 385        struct snd_card *card;
 386        struct snd_pcm_runtime *runtime;
 387        struct snd_dma_buffer *dmab = NULL;
 388
 389        if (PCM_RUNTIME_CHECK(substream))
 390                return -EINVAL;
 391        if (snd_BUG_ON(substream->dma_buffer.dev.type ==
 392                       SNDRV_DMA_TYPE_UNKNOWN))
 393                return -EINVAL;
 394        runtime = substream->runtime;
 395        card = substream->pcm->card;
 396
 397        if (runtime->dma_buffer_p) {
 398                /* perphaps, we might free the large DMA memory region
 399                   to save some space here, but the actual solution
 400                   costs us less time */
 401                if (runtime->dma_buffer_p->bytes >= size) {
 402                        runtime->dma_bytes = size;
 403                        return 0;       /* ok, do not change */
 404                }
 405                snd_pcm_lib_free_pages(substream);
 406        }
 407        if (substream->dma_buffer.area != NULL &&
 408            substream->dma_buffer.bytes >= size) {
 409                dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
 410        } else {
 411                /* dma_max=0 means the fixed size preallocation */
 412                if (substream->dma_buffer.area && !substream->dma_max)
 413                        return -ENOMEM;
 414                dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
 415                if (! dmab)
 416                        return -ENOMEM;
 417                dmab->dev = substream->dma_buffer.dev;
 418                if (do_alloc_pages(card,
 419                                   substream->dma_buffer.dev.type,
 420                                   substream->dma_buffer.dev.dev,
 421                                   size, dmab) < 0) {
 422                        kfree(dmab);
 423                        pr_debug("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
 424                                 substream->pcm->card->number, substream->pcm->device,
 425                                 substream->stream ? 'c' : 'p', substream->number,
 426                                 substream->pcm->name, size);
 427                        return -ENOMEM;
 428                }
 429        }
 430        snd_pcm_set_runtime_buffer(substream, dmab);
 431        runtime->dma_bytes = size;
 432        return 1;                       /* area was changed */
 433}
 434EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
 435
 436/**
 437 * snd_pcm_lib_free_pages - release the allocated DMA buffer.
 438 * @substream: the substream to release the DMA buffer
 439 *
 440 * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
 441 *
 442 * Return: Zero if successful, or a negative error code on failure.
 443 */
 444int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
 445{
 446        struct snd_card *card = substream->pcm->card;
 447        struct snd_pcm_runtime *runtime;
 448
 449        if (PCM_RUNTIME_CHECK(substream))
 450                return -EINVAL;
 451        runtime = substream->runtime;
 452        if (runtime->dma_area == NULL)
 453                return 0;
 454        if (runtime->dma_buffer_p != &substream->dma_buffer) {
 455                /* it's a newly allocated buffer.  release it now. */
 456                do_free_pages(card, runtime->dma_buffer_p);
 457                kfree(runtime->dma_buffer_p);
 458        }
 459        snd_pcm_set_runtime_buffer(substream, NULL);
 460        return 0;
 461}
 462EXPORT_SYMBOL(snd_pcm_lib_free_pages);
 463
 464int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
 465                                      size_t size, gfp_t gfp_flags)
 466{
 467        struct snd_pcm_runtime *runtime;
 468
 469        if (PCM_RUNTIME_CHECK(substream))
 470                return -EINVAL;
 471        runtime = substream->runtime;
 472        if (runtime->dma_area) {
 473                if (runtime->dma_bytes >= size)
 474                        return 0; /* already large enough */
 475                vfree(runtime->dma_area);
 476        }
 477        runtime->dma_area = __vmalloc(size, gfp_flags);
 478        if (!runtime->dma_area)
 479                return -ENOMEM;
 480        runtime->dma_bytes = size;
 481        return 1;
 482}
 483EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
 484
 485/**
 486 * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
 487 * @substream: the substream with a buffer allocated by
 488 *      snd_pcm_lib_alloc_vmalloc_buffer()
 489 *
 490 * Return: Zero if successful, or a negative error code on failure.
 491 */
 492int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
 493{
 494        struct snd_pcm_runtime *runtime;
 495
 496        if (PCM_RUNTIME_CHECK(substream))
 497                return -EINVAL;
 498        runtime = substream->runtime;
 499        vfree(runtime->dma_area);
 500        runtime->dma_area = NULL;
 501        return 0;
 502}
 503EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
 504
 505/**
 506 * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
 507 * @substream: the substream with a buffer allocated by
 508 *      snd_pcm_lib_alloc_vmalloc_buffer()
 509 * @offset: offset in the buffer
 510 *
 511 * This function is to be used as the page callback in the PCM ops.
 512 *
 513 * Return: The page struct, or %NULL on failure.
 514 */
 515struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
 516                                          unsigned long offset)
 517{
 518        return vmalloc_to_page(substream->runtime->dma_area + offset);
 519}
 520EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);
 521