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