sound/core/pcm_memory.c

   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
  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.");
  22
  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.");
  26
  27 static const size_t snd_minimum_buffer = 16384;
  28
  29 static unsigned long max_alloc_per_card = 32UL * 1024UL * 1024UL;
  30 module_param(max_alloc_per_card, ulong, 0644);
  31 MODULE_PARM_DESC(max_alloc_per_card, "Max total allocation bytes per card.");
  32
  33 static void __update_allocated_size(struct snd_card *card, ssize_t bytes)
  34 {
  35         card->total_pcm_alloc_bytes += bytes;
  36 }
  37
  38 static void update_allocated_size(struct snd_card *card, ssize_t bytes)
  39 {
  40         mutex_lock(&card->memory_mutex);
  41         __update_allocated_size(card, bytes);
  42         mutex_unlock(&card->memory_mutex);
  43 }
  44
  45 static void decrease_allocated_size(struct snd_card *card, size_t bytes)
  46 {
  47         mutex_lock(&card->memory_mutex);
  48         WARN_ON(card->total_pcm_alloc_bytes < bytes);
  49         __update_allocated_size(card, -(ssize_t)bytes);
  50         mutex_unlock(&card->memory_mutex);
  51 }
  52
  53 static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
  54                           size_t size, struct snd_dma_buffer *dmab)
  55 {
  56         int err;
  57
  58         /* check and reserve the requested size */
  59         mutex_lock(&card->memory_mutex);
  60         if (max_alloc_per_card &&
  61             card->total_pcm_alloc_bytes + size > max_alloc_per_card) {
  62                 mutex_unlock(&card->memory_mutex);
  63                 return -ENOMEM;
  64         }
  65         __update_allocated_size(card, size);
  66         mutex_unlock(&card->memory_mutex);
  67
  68         err = snd_dma_alloc_pages(type, dev, size, dmab);
  69         if (!err) {
  70                 /* the actual allocation size might be bigger than requested,
  71                  * and we need to correct the account
  72                  */
  73                 if (dmab->bytes != size)
  74                         update_allocated_size(card, dmab->bytes - size);
  75         } else {
  76                 /* take back on allocation failure */
  77                 decrease_allocated_size(card, size);
  78         }
  79         return err;
  80 }
  81
  82 static void do_free_pages(struct snd_card *card, struct snd_dma_buffer *dmab)
  83 {
  84         if (!dmab->area)
  85                 return;
  86         decrease_allocated_size(card, dmab->bytes);
  87         snd_dma_free_pages(dmab);
  88         dmab->area = NULL;
  89 }
  90
  91 /*
  92  * try to allocate as the large pages as possible.
  93  * stores the resultant memory size in *res_size.
  94  *
  95  * the minimum size is snd_minimum_buffer.  it should be power of 2.
  96  */
  97 static int preallocate_pcm_pages(struct snd_pcm_substream *substream, size_t size)
  98 {
  99         struct snd_dma_buffer *dmab = &substream->dma_buffer;
 100         struct snd_card *card = substream->pcm->card;
 101         size_t orig_size = size;
 102         int err;
 103
 104         do {
 105                 err = do_alloc_pages(card, dmab->dev.type, dmab->dev.dev,
 106                                      size, dmab);
 107                 if (err != -ENOMEM)
 108                         return err;
 109                 size >>= 1;
 110         } while (size >= snd_minimum_buffer);
 111         dmab->bytes = 0; /* tell error */
 112         pr_warn("ALSA pcmC%dD%d%c,%d:%s: cannot preallocate for size %zu\n",
 113                 substream->pcm->card->number, substream->pcm->device,
 114                 substream->stream ? 'c' : 'p', substream->number,
 115                 substream->pcm->name, orig_size);
 116         return 0;
 117 }
 118
 119 /*
 120  * release the preallocated buffer if not yet done.
 121  */
 122 static void snd_pcm_lib_preallocate_dma_free(struct snd_pcm_substream *substream)
 123 {
 124         do_free_pages(substream->pcm->card, &substream->dma_buffer);
 125 }
 126
 127 /**
 128  * snd_pcm_lib_preallocate_free - release the preallocated buffer of the specified substream.
 129  * @substream: the pcm substream instance
 130  *
 131  * Releases the pre-allocated buffer of the given substream.
 132  */
 133 void snd_pcm_lib_preallocate_free(struct snd_pcm_substream *substream)
 134 {
 135         snd_pcm_lib_preallocate_dma_free(substream);
 136 }
 137
 138 /**
 139  * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
 140  * @pcm: the pcm instance
 141  *
 142  * Releases all the pre-allocated buffers on the given pcm.
 143  */
 144 void snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
 145 {
 146         struct snd_pcm_substream *substream;
 147         int stream;
 148
 149         for (stream = 0; stream < 2; stream++)
 150                 for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
 151                         snd_pcm_lib_preallocate_free(substream);
 152 }
 153 EXPORT_SYMBOL(snd_pcm_lib_preallocate_free_for_all);
 154
 155 #ifdef CONFIG_SND_VERBOSE_PROCFS
 156 /*
 157  * read callback for prealloc proc file
 158  *
 159  * prints the current allocated size in kB.
 160  */
 161 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
 162                                               struct snd_info_buffer *buffer)
 163 {
 164         struct snd_pcm_substream *substream = entry->private_data;
 165         snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
 166 }
 167
 168 /*
 169  * read callback for prealloc_max proc file
 170  *
 171  * prints the maximum allowed size in kB.
 172  */
 173 static void snd_pcm_lib_preallocate_max_proc_read(struct snd_info_entry *entry,
 174                                                   struct snd_info_buffer *buffer)
 175 {
 176         struct snd_pcm_substream *substream = entry->private_data;
 177         snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_max / 1024);
 178 }
 179
 180 /*
 181  * write callback for prealloc proc file
 182  *
 183  * accepts the preallocation size in kB.
 184  */
 185 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
 186                                                struct snd_info_buffer *buffer)
 187 {
 188         struct snd_pcm_substream *substream = entry->private_data;
 189         struct snd_card *card = substream->pcm->card;
 190         char line[64], str[64];
 191         size_t size;
 192         struct snd_dma_buffer new_dmab;
 193
 194         mutex_lock(&substream->pcm->open_mutex);
 195         if (substream->runtime) {
 196                 buffer->error = -EBUSY;
 197                 goto unlock;
 198         }
 199         if (!snd_info_get_line(buffer, line, sizeof(line))) {
 200                 snd_info_get_str(str, line, sizeof(str));
 201                 size = simple_strtoul(str, NULL, 10) * 1024;
 202                 if ((size != 0 && size < 8192) || size > substream->dma_max) {
 203                         buffer->error = -EINVAL;
 204                         goto unlock;
 205                 }
 206                 if (substream->dma_buffer.bytes == size)
 207                         goto unlock;
 208                 memset(&new_dmab, 0, sizeof(new_dmab));
 209                 new_dmab.dev = substream->dma_buffer.dev;
 210                 if (size > 0) {
 211                         if (do_alloc_pages(card,
 212                                            substream->dma_buffer.dev.type,
 213                                            substream->dma_buffer.dev.dev,
 214                                            size, &new_dmab) < 0) {
 215                                 buffer->error = -ENOMEM;
 216                                 goto unlock;
 217                         }
 218                         substream->buffer_bytes_max = size;
 219                 } else {
 220                         substream->buffer_bytes_max = UINT_MAX;
 221                 }
 222                 if (substream->dma_buffer.area)
 223                         do_free_pages(card, &substream->dma_buffer);
 224                 substream->dma_buffer = new_dmab;
 225         } else {
 226                 buffer->error = -EINVAL;
 227         }
 228  unlock:
 229         mutex_unlock(&substream->pcm->open_mutex);
 230 }
 231
 232 static inline void preallocate_info_init(struct snd_pcm_substream *substream)
 233 {
 234         struct snd_info_entry *entry;
 235
 236         entry = snd_info_create_card_entry(substream->pcm->card, "prealloc",
 237                                            substream->proc_root);
 238         if (entry) {
 239                 snd_info_set_text_ops(entry, substream,
 240                                       snd_pcm_lib_preallocate_proc_read);
 241                 entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
 242                 entry->mode |= 0200;
 243         }
 244         entry = snd_info_create_card_entry(substream->pcm->card, "prealloc_max",
 245                                            substream->proc_root);
 246         if (entry)
 247                 snd_info_set_text_ops(entry, substream,
 248                                       snd_pcm_lib_preallocate_max_proc_read);
 249 }
 250
 251 #else /* !CONFIG_SND_VERBOSE_PROCFS */
 252 #define preallocate_info_init(s)
 253 #endif /* CONFIG_SND_VERBOSE_PROCFS */
 254
 255 /*
 256  * pre-allocate the buffer and create a proc file for the substream
 257  */
 258 static void snd_pcm_lib_preallocate_pages1(struct snd_pcm_substream *substream,
 259                                           size_t size, size_t max)
 260 {
 261
 262         if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
 263                 preallocate_pcm_pages(substream, size);
 264
 265         if (substream->dma_buffer.bytes > 0)
 266                 substream->buffer_bytes_max = substream->dma_buffer.bytes;
 267         substream->dma_max = max;
 268         preallocate_info_init(substream);
 269 }
 270
 271
 272 /**
 273  * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
 274  * @substream: the pcm substream instance
 275  * @type: DMA type (SNDRV_DMA_TYPE_*)
 276  * @data: DMA type dependent data
 277  * @size: the requested pre-allocation size in bytes
 278  * @max: the max. allowed pre-allocation size
 279  *
 280  * Do pre-allocation for the given DMA buffer type.
 281  */
 282 void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
 283                                   int type, struct device *data,
 284                                   size_t size, size_t max)
 285 {
 286         substream->dma_buffer.dev.type = type;
 287         substream->dma_buffer.dev.dev = data;
 288         snd_pcm_lib_preallocate_pages1(substream, size, max);
 289 }
 290 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages);
 291
 292 /**
 293  * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continuous memory type (all substreams)
 294  * @pcm: the pcm instance
 295  * @type: DMA type (SNDRV_DMA_TYPE_*)
 296  * @data: DMA type dependent data
 297  * @size: the requested pre-allocation size in bytes
 298  * @max: the max. allowed pre-allocation size
 299  *
 300  * Do pre-allocation to all substreams of the given pcm for the
 301  * specified DMA type.
 302  */
 303 void snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
 304                                           int type, void *data,
 305                                           size_t size, size_t max)
 306 {
 307         struct snd_pcm_substream *substream;
 308         int stream;
 309
 310         for (stream = 0; stream < 2; stream++)
 311                 for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
 312                         snd_pcm_lib_preallocate_pages(substream, type, data, size, max);
 313 }
 314 EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
 315
 316 #ifdef CONFIG_SND_DMA_SGBUF
 317 /**
 318  * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
 319  * @substream: the pcm substream instance
 320  * @offset: the buffer offset
 321  *
 322  * Used as the page callback of PCM ops.
 323  *
 324  * Return: The page struct at the given buffer offset. %NULL on failure.
 325  */
 326 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
 327 {
 328         struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
 329
 330         unsigned int idx = offset >> PAGE_SHIFT;
 331         if (idx >= (unsigned int)sgbuf->pages)
 332                 return NULL;
 333         return sgbuf->page_table[idx];
 334 }
 335 EXPORT_SYMBOL(snd_pcm_sgbuf_ops_page);
 336 #endif /* CONFIG_SND_DMA_SGBUF */
 337
 338 /**
 339  * snd_pcm_lib_malloc_pages - allocate the DMA buffer
 340  * @substream: the substream to allocate the DMA buffer to
 341  * @size: the requested buffer size in bytes
 342  *
 343  * Allocates the DMA buffer on the BUS type given earlier to
 344  * snd_pcm_lib_preallocate_xxx_pages().
 345  *
 346  * Return: 1 if the buffer is changed, 0 if not changed, or a negative
 347  * code on failure.
 348  */
 349 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
 350 {
 351         struct snd_card *card = substream->pcm->card;
 352         struct snd_pcm_runtime *runtime;
 353         struct snd_dma_buffer *dmab = NULL;
 354
 355         if (PCM_RUNTIME_CHECK(substream))
 356                 return -EINVAL;
 357         if (snd_BUG_ON(substream->dma_buffer.dev.type ==
 358                        SNDRV_DMA_TYPE_UNKNOWN))
 359                 return -EINVAL;
 360         runtime = substream->runtime;
 361
 362         if (runtime->dma_buffer_p) {
 363                 /* perphaps, we might free the large DMA memory region
 364                    to save some space here, but the actual solution
 365                    costs us less time */
 366                 if (runtime->dma_buffer_p->bytes >= size) {
 367                         runtime->dma_bytes = size;
 368                         return 0;       /* ok, do not change */
 369                 }
 370                 snd_pcm_lib_free_pages(substream);
 371         }
 372         if (substream->dma_buffer.area != NULL &&
 373             substream->dma_buffer.bytes >= size) {
 374                 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
 375         } else {
 376                 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
 377                 if (! dmab)
 378                         return -ENOMEM;
 379                 dmab->dev = substream->dma_buffer.dev;
 380                 if (do_alloc_pages(card,
 381                                    substream->dma_buffer.dev.type,
 382                                    substream->dma_buffer.dev.dev,
 383                                    size, dmab) < 0) {
 384                         kfree(dmab);
 385                         return -ENOMEM;
 386                 }
 387         }
 388         snd_pcm_set_runtime_buffer(substream, dmab);
 389         runtime->dma_bytes = size;
 390         return 1;                       /* area was changed */
 391 }
 392 EXPORT_SYMBOL(snd_pcm_lib_malloc_pages);
 393
 394 /**
 395  * snd_pcm_lib_free_pages - release the allocated DMA buffer.
 396  * @substream: the substream to release the DMA buffer
 397  *
 398  * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
 399  *
 400  * Return: Zero if successful, or a negative error code on failure.
 401  */
 402 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
 403 {
 404         struct snd_pcm_runtime *runtime;
 405
 406         if (PCM_RUNTIME_CHECK(substream))
 407                 return -EINVAL;
 408         runtime = substream->runtime;
 409         if (runtime->dma_area == NULL)
 410                 return 0;
 411         if (runtime->dma_buffer_p != &substream->dma_buffer) {
 412                 struct snd_card *card = substream->pcm->card;
 413
 414                 /* it's a newly allocated buffer.  release it now. */
 415                 do_free_pages(card, runtime->dma_buffer_p);
 416                 kfree(runtime->dma_buffer_p);
 417         }
 418         snd_pcm_set_runtime_buffer(substream, NULL);
 419         return 0;
 420 }
 421 EXPORT_SYMBOL(snd_pcm_lib_free_pages);
 422
 423 int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
 424                                       size_t size, gfp_t gfp_flags)
 425 {
 426         struct snd_pcm_runtime *runtime;
 427
 428         if (PCM_RUNTIME_CHECK(substream))
 429                 return -EINVAL;
 430         runtime = substream->runtime;
 431         if (runtime->dma_area) {
 432                 if (runtime->dma_bytes >= size)
 433                         return 0; /* already large enough */
 434                 vfree(runtime->dma_area);
 435         }
 436         runtime->dma_area = __vmalloc(size, gfp_flags, PAGE_KERNEL);
 437         if (!runtime->dma_area)
 438                 return -ENOMEM;
 439         runtime->dma_bytes = size;
 440         return 1;
 441 }
 442 EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
 443
 444 /**
 445  * snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
 446  * @substream: the substream with a buffer allocated by
 447  *      snd_pcm_lib_alloc_vmalloc_buffer()
 448  *
 449  * Return: Zero if successful, or a negative error code on failure.
 450  */
 451 int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
 452 {
 453         struct snd_pcm_runtime *runtime;
 454
 455         if (PCM_RUNTIME_CHECK(substream))
 456                 return -EINVAL;
 457         runtime = substream->runtime;
 458         vfree(runtime->dma_area);
 459         runtime->dma_area = NULL;
 460         return 0;
 461 }
 462 EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
 463
 464 /**
 465  * snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
 466  * @substream: the substream with a buffer allocated by
 467  *      snd_pcm_lib_alloc_vmalloc_buffer()
 468  * @offset: offset in the buffer
 469  *
 470  * This function is to be used as the page callback in the PCM ops.
 471  *
 472  * Return: The page struct, or %NULL on failure.
 473  */
 474 struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
 475                                           unsigned long offset)
 476 {
 477         return vmalloc_to_page(substream->runtime->dma_area + offset);
 478 }
 479 EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);