sound/core/pcm_memory.c

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