sound/core/sgbuf.c

   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
  22 #include <linux/slab.h>
  23 #include <linux/mm.h>
  24 #include <linux/vmalloc.h>
  25 #include <sound/memalloc.h>
  26
  27
  28 /* table entries are align to 32 */
  29 #define SGBUF_TBL_ALIGN         32
  30 #define sgbuf_align_table(tbl)  ((((tbl) + SGBUF_TBL_ALIGN - 1) / SGBUF_TBL_ALIGN) * SGBUF_TBL_ALIGN)
  31
  32 int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
  33 {
  34         struct snd_sg_buf *sgbuf = dmab->private_data;
  35         struct snd_dma_buffer tmpb;
  36         int i;
  37
  38         if (! sgbuf)
  39                 return -EINVAL;
  40
  41         tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
  42         tmpb.dev.dev = sgbuf->dev;
  43         for (i = 0; i < sgbuf->pages; i++) {
  44                 tmpb.area = sgbuf->table[i].buf;
  45                 tmpb.addr = sgbuf->table[i].addr;
  46                 tmpb.bytes = PAGE_SIZE;
  47                 snd_dma_free_pages(&tmpb);
  48         }
  49         if (dmab->area)
  50                 vunmap(dmab->area);
  51         dmab->area = NULL;
  52
  53         kfree(sgbuf->table);
  54         kfree(sgbuf->page_table);
  55         kfree(sgbuf);
  56         dmab->private_data = NULL;
  57
  58         return 0;
  59 }
  60
  61 void *snd_malloc_sgbuf_pages(struct device *device,
  62                              size_t size, struct snd_dma_buffer *dmab,
  63                              size_t *res_size)
  64 {
  65         struct snd_sg_buf *sgbuf;
  66         unsigned int i, pages;
  67         struct snd_dma_buffer tmpb;
  68
  69         dmab->area = NULL;
  70         dmab->addr = 0;
  71         dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
  72         if (! sgbuf)
  73                 return NULL;
  74         sgbuf->dev = device;
  75         pages = snd_sgbuf_aligned_pages(size);
  76         sgbuf->tblsize = sgbuf_align_table(pages);
  77         sgbuf->table = kcalloc(sgbuf->tblsize, sizeof(*sgbuf->table), GFP_KERNEL);
  78         if (! sgbuf->table)
  79                 goto _failed;
  80         sgbuf->page_table = kcalloc(sgbuf->tblsize, sizeof(*sgbuf->page_table), GFP_KERNEL);
  81         if (! sgbuf->page_table)
  82                 goto _failed;
  83
  84         /* allocate each page */
  85         for (i = 0; i < pages; i++) {
  86                 if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, device, PAGE_SIZE, &tmpb) < 0) {
  87                         if (res_size == NULL)
  88                                 goto _failed;
  89                         *res_size = size = sgbuf->pages * PAGE_SIZE;
  90                         break;
  91                 }
  92                 sgbuf->table[i].buf = tmpb.area;
  93                 sgbuf->table[i].addr = tmpb.addr;
  94                 sgbuf->page_table[i] = virt_to_page(tmpb.area);
  95                 sgbuf->pages++;
  96         }
  97
  98         sgbuf->size = size;
  99         dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
 100         if (! dmab->area)
 101                 goto _failed;
 102         return dmab->area;
 103
 104  _failed:
 105         snd_free_sgbuf_pages(dmab); /* free the table */
 106         return NULL;
 107 }