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         if (substream->proc_prealloc_entry) {
 104                 snd_info_unregister(substream->proc_prealloc_entry);
 105                 substream->proc_prealloc_entry = NULL;
 106         }
 107         return 0;
 108 }
 109
 110 /**
 111  * snd_pcm_lib_preallocate_free_for_all - release all pre-allocated buffers on the pcm
 112  * @pcm: the pcm instance
 113  *
 114  * Releases all the pre-allocated buffers on the given pcm.
 115  *
 116  * Returns zero if successful, or a negative error code on failure.
 117  */
 118 int snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm)
 119 {
 120         struct snd_pcm_substream *substream;
 121         int stream;
 122
 123         for (stream = 0; stream < 2; stream++)
 124                 for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
 125                         snd_pcm_lib_preallocate_free(substream);
 126         return 0;
 127 }
 128
 129 /*
 130  * read callback for prealloc proc file
 131  *
 132  * prints the current allocated size in kB.
 133  */
 134 static void snd_pcm_lib_preallocate_proc_read(struct snd_info_entry *entry,
 135                                               struct snd_info_buffer *buffer)
 136 {
 137         struct snd_pcm_substream *substream = entry->private_data;
 138         snd_iprintf(buffer, "%lu\n", (unsigned long) substream->dma_buffer.bytes / 1024);
 139 }
 140
 141 /*
 142  * write callback for prealloc proc file
 143  *
 144  * accepts the preallocation size in kB.
 145  */
 146 static void snd_pcm_lib_preallocate_proc_write(struct snd_info_entry *entry,
 147                                                struct snd_info_buffer *buffer)
 148 {
 149         struct snd_pcm_substream *substream = entry->private_data;
 150         char line[64], str[64];
 151         size_t size;
 152         struct snd_dma_buffer new_dmab;
 153
 154         if (substream->runtime) {
 155                 buffer->error = -EBUSY;
 156                 return;
 157         }
 158         if (!snd_info_get_line(buffer, line, sizeof(line))) {
 159                 snd_info_get_str(str, line, sizeof(str));
 160                 size = simple_strtoul(str, NULL, 10) * 1024;
 161                 if ((size != 0 && size < 8192) || size > substream->dma_max) {
 162                         buffer->error = -EINVAL;
 163                         return;
 164                 }
 165                 if (substream->dma_buffer.bytes == size)
 166                         return;
 167                 memset(&new_dmab, 0, sizeof(new_dmab));
 168                 new_dmab.dev = substream->dma_buffer.dev;
 169                 if (size > 0) {
 170                         if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
 171                                                 substream->dma_buffer.dev.dev,
 172                                                 size, &new_dmab) < 0) {
 173                                 buffer->error = -ENOMEM;
 174                                 return;
 175                         }
 176                         substream->buffer_bytes_max = size;
 177                 } else {
 178                         substream->buffer_bytes_max = UINT_MAX;
 179                 }
 180                 if (substream->dma_buffer.area)
 181                         snd_dma_free_pages(&substream->dma_buffer);
 182                 substream->dma_buffer = new_dmab;
 183         } else {
 184                 buffer->error = -EINVAL;
 185         }
 186 }
 187
 188 /*
 189  * pre-allocate the buffer and create a proc file for the substream
 190  */
 191 static int snd_pcm_lib_preallocate_pages1(struct snd_pcm_substream *substream,
 192                                           size_t size, size_t max)
 193 {
 194         struct snd_info_entry *entry;
 195
 196         if (size > 0 && preallocate_dma && substream->number < maximum_substreams)
 197                 preallocate_pcm_pages(substream, size);
 198
 199         if (substream->dma_buffer.bytes > 0)
 200                 substream->buffer_bytes_max = substream->dma_buffer.bytes;
 201         substream->dma_max = max;
 202         if ((entry = snd_info_create_card_entry(substream->pcm->card, "prealloc", substream->proc_root)) != NULL) {
 203                 entry->c.text.read_size = 64;
 204                 entry->c.text.read = snd_pcm_lib_preallocate_proc_read;
 205                 entry->c.text.write_size = 64;
 206                 entry->c.text.write = snd_pcm_lib_preallocate_proc_write;
 207                 entry->mode |= S_IWUSR;
 208                 entry->private_data = substream;
 209                 if (snd_info_register(entry) < 0) {
 210                         snd_info_free_entry(entry);
 211                         entry = NULL;
 212                 }
 213         }
 214         substream->proc_prealloc_entry = entry;
 215         return 0;
 216 }
 217
 218
 219 /**
 220  * snd_pcm_lib_preallocate_pages - pre-allocation for the given DMA type
 221  * @substream: the pcm substream instance
 222  * @type: DMA type (SNDRV_DMA_TYPE_*)
 223  * @data: DMA type dependant data
 224  * @size: the requested pre-allocation size in bytes
 225  * @max: the max. allowed pre-allocation size
 226  *
 227  * Do pre-allocation for the given DMA buffer type.
 228  *
 229  * When substream->dma_buf_id is set, the function tries to look for
 230  * the reserved buffer, and the buffer is not freed but reserved at
 231  * destruction time.  The dma_buf_id must be unique for all systems
 232  * (in the same DMA buffer type) e.g. using snd_dma_pci_buf_id().
 233  *
 234  * Returns zero if successful, or a negative error code on failure.
 235  */
 236 int snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
 237                                   int type, struct device *data,
 238                                   size_t size, size_t max)
 239 {
 240         substream->dma_buffer.dev.type = type;
 241         substream->dma_buffer.dev.dev = data;
 242         return snd_pcm_lib_preallocate_pages1(substream, size, max);
 243 }
 244
 245 /**
 246  * snd_pcm_lib_preallocate_pages_for_all - pre-allocation for continous memory type (all substreams)
 247  * @pcm: the pcm instance
 248  * @type: DMA type (SNDRV_DMA_TYPE_*)
 249  * @data: DMA type dependant data
 250  * @size: the requested pre-allocation size in bytes
 251  * @max: the max. allowed pre-allocation size
 252  *
 253  * Do pre-allocation to all substreams of the given pcm for the
 254  * specified DMA type.
 255  *
 256  * Returns zero if successful, or a negative error code on failure.
 257  */
 258 int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
 259                                           int type, void *data,
 260                                           size_t size, size_t max)
 261 {
 262         struct snd_pcm_substream *substream;
 263         int stream, err;
 264
 265         for (stream = 0; stream < 2; stream++)
 266                 for (substream = pcm->streams[stream].substream; substream; substream = substream->next)
 267                         if ((err = snd_pcm_lib_preallocate_pages(substream, type, data, size, max)) < 0)
 268                                 return err;
 269         return 0;
 270 }
 271
 272 /**
 273  * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
 274  * @substream: the pcm substream instance
 275  * @offset: the buffer offset
 276  *
 277  * Returns the page struct at the given buffer offset.
 278  * Used as the page callback of PCM ops.
 279  */
 280 struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
 281 {
 282         struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
 283
 284         unsigned int idx = offset >> PAGE_SHIFT;
 285         if (idx >= (unsigned int)sgbuf->pages)
 286                 return NULL;
 287         return sgbuf->page_table[idx];
 288 }
 289
 290 /**
 291  * snd_pcm_lib_malloc_pages - allocate the DMA buffer
 292  * @substream: the substream to allocate the DMA buffer to
 293  * @size: the requested buffer size in bytes
 294  *
 295  * Allocates the DMA buffer on the BUS type given earlier to
 296  * snd_pcm_lib_preallocate_xxx_pages().
 297  *
 298  * Returns 1 if the buffer is changed, 0 if not changed, or a negative
 299  * code on failure.
 300  */
 301 int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size)
 302 {
 303         struct snd_pcm_runtime *runtime;
 304         struct snd_dma_buffer *dmab = NULL;
 305
 306         snd_assert(substream->dma_buffer.dev.type != SNDRV_DMA_TYPE_UNKNOWN, return -EINVAL);
 307         snd_assert(substream != NULL, return -EINVAL);
 308         runtime = substream->runtime;
 309         snd_assert(runtime != NULL, return -EINVAL);
 310
 311         if (runtime->dma_buffer_p) {
 312                 /* perphaps, we might free the large DMA memory region
 313                    to save some space here, but the actual solution
 314                    costs us less time */
 315                 if (runtime->dma_buffer_p->bytes >= size) {
 316                         runtime->dma_bytes = size;
 317                         return 0;       /* ok, do not change */
 318                 }
 319                 snd_pcm_lib_free_pages(substream);
 320         }
 321         if (substream->dma_buffer.area != NULL &&
 322             substream->dma_buffer.bytes >= size) {
 323                 dmab = &substream->dma_buffer; /* use the pre-allocated buffer */
 324         } else {
 325                 dmab = kzalloc(sizeof(*dmab), GFP_KERNEL);
 326                 if (! dmab)
 327                         return -ENOMEM;
 328                 dmab->dev = substream->dma_buffer.dev;
 329                 if (snd_dma_alloc_pages(substream->dma_buffer.dev.type,
 330                                         substream->dma_buffer.dev.dev,
 331                                         size, dmab) < 0) {
 332                         kfree(dmab);
 333                         return -ENOMEM;
 334                 }
 335         }
 336         snd_pcm_set_runtime_buffer(substream, dmab);
 337         runtime->dma_bytes = size;
 338         return 1;                       /* area was changed */
 339 }
 340
 341 /**
 342  * snd_pcm_lib_free_pages - release the allocated DMA buffer.
 343  * @substream: the substream to release the DMA buffer
 344  *
 345  * Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages().
 346  *
 347  * Returns zero if successful, or a negative error code on failure.
 348  */
 349 int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
 350 {
 351         struct snd_pcm_runtime *runtime;
 352
 353         snd_assert(substream != NULL, return -EINVAL);
 354         runtime = substream->runtime;
 355         snd_assert(runtime != NULL, return -EINVAL);
 356         if (runtime->dma_area == NULL)
 357                 return 0;
 358         if (runtime->dma_buffer_p != &substream->dma_buffer) {
 359                 /* it's a newly allocated buffer.  release it now. */
 360                 snd_dma_free_pages(runtime->dma_buffer_p);
 361                 kfree(runtime->dma_buffer_p);
 362         }
 363         snd_pcm_set_runtime_buffer(substream, NULL);
 364         return 0;
 365 }