sgbuf.c 2.9 KB

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  1. /*
  2. * Scatter-Gather buffer
  3. *
  4. * Copyright (c) by Takashi Iwai <tiwai@suse.de>
  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. #include <linux/slab.h>
  22. #include <linux/mm.h>
  23. #include <linux/vmalloc.h>
  24. #include <sound/memalloc.h>
  25. /* table entries are align to 32 */
  26. #define SGBUF_TBL_ALIGN 32
  27. #define sgbuf_align_table(tbl) ALIGN((tbl), SGBUF_TBL_ALIGN)
  28. int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
  29. {
  30. struct snd_sg_buf *sgbuf = dmab->private_data;
  31. struct snd_dma_buffer tmpb;
  32. int i;
  33. if (! sgbuf)
  34. return -EINVAL;
  35. tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
  36. tmpb.dev.dev = sgbuf->dev;
  37. for (i = 0; i < sgbuf->pages; i++) {
  38. tmpb.area = sgbuf->table[i].buf;
  39. tmpb.addr = sgbuf->table[i].addr;
  40. tmpb.bytes = PAGE_SIZE;
  41. snd_dma_free_pages(&tmpb);
  42. }
  43. if (dmab->area)
  44. vunmap(dmab->area);
  45. dmab->area = NULL;
  46. kfree(sgbuf->table);
  47. kfree(sgbuf->page_table);
  48. kfree(sgbuf);
  49. dmab->private_data = NULL;
  50. return 0;
  51. }
  52. void *snd_malloc_sgbuf_pages(struct device *device,
  53. size_t size, struct snd_dma_buffer *dmab,
  54. size_t *res_size)
  55. {
  56. struct snd_sg_buf *sgbuf;
  57. unsigned int i, pages;
  58. struct snd_dma_buffer tmpb;
  59. dmab->area = NULL;
  60. dmab->addr = 0;
  61. dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
  62. if (! sgbuf)
  63. return NULL;
  64. sgbuf->dev = device;
  65. pages = snd_sgbuf_aligned_pages(size);
  66. sgbuf->tblsize = sgbuf_align_table(pages);
  67. sgbuf->table = kcalloc(sgbuf->tblsize, sizeof(*sgbuf->table), GFP_KERNEL);
  68. if (! sgbuf->table)
  69. goto _failed;
  70. sgbuf->page_table = kcalloc(sgbuf->tblsize, sizeof(*sgbuf->page_table), GFP_KERNEL);
  71. if (! sgbuf->page_table)
  72. goto _failed;
  73. /* allocate each page */
  74. for (i = 0; i < pages; i++) {
  75. if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, device, PAGE_SIZE, &tmpb) < 0) {
  76. if (res_size == NULL)
  77. goto _failed;
  78. *res_size = size = sgbuf->pages * PAGE_SIZE;
  79. break;
  80. }
  81. sgbuf->table[i].buf = tmpb.area;
  82. sgbuf->table[i].addr = tmpb.addr;
  83. sgbuf->page_table[i] = virt_to_page(tmpb.area);
  84. sgbuf->pages++;
  85. }
  86. sgbuf->size = size;
  87. dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
  88. if (! dmab->area)
  89. goto _failed;
  90. return dmab->area;
  91. _failed:
  92. snd_free_sgbuf_pages(dmab); /* free the table */
  93. return NULL;
  94. }