LXR linux/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)  ALIGN((tbl), SGBUF_TBL_ALIGN)
  31
  32int 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        if (dmab->area)
  42                vunmap(dmab->area);
  43        dmab->area = NULL;
  44
  45        tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
  46        tmpb.dev.dev = sgbuf->dev;
  47        for (i = 0; i < sgbuf->pages; i++) {
  48                tmpb.area = sgbuf->table[i].buf;
  49                tmpb.addr = sgbuf->table[i].addr;
  50                tmpb.bytes = PAGE_SIZE;
  51                snd_dma_free_pages(&tmpb);
  52        }
  53
  54        kfree(sgbuf->table);
  55        kfree(sgbuf->page_table);
  56        kfree(sgbuf);
  57        dmab->private_data = NULL;
  58        
  59        return 0;
  60}
  61
  62void *snd_malloc_sgbuf_pages(struct device *device,
  63                             size_t size, struct snd_dma_buffer *dmab,
  64                             size_t *res_size)
  65{
  66        struct snd_sg_buf *sgbuf;
  67        unsigned int i, pages;
  68        struct snd_dma_buffer tmpb;
  69
  70        dmab->area = NULL;
  71        dmab->addr = 0;
  72        dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
  73        if (! sgbuf)
  74                return NULL;
  75        sgbuf->dev = device;
  76        pages = snd_sgbuf_aligned_pages(size);
  77        sgbuf->tblsize = sgbuf_align_table(pages);
  78        sgbuf->table = kcalloc(sgbuf->tblsize, sizeof(*sgbuf->table), GFP_KERNEL);
  79        if (! sgbuf->table)
  80                goto _failed;
  81        sgbuf->page_table = kcalloc(sgbuf->tblsize, sizeof(*sgbuf->page_table), GFP_KERNEL);
  82        if (! sgbuf->page_table)
  83                goto _failed;
  84
  85        /* allocate each page */
  86        for (i = 0; i < pages; i++) {
  87                if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, device, PAGE_SIZE, &tmpb) < 0) {
  88                        if (res_size == NULL)
  89                                goto _failed;
  90                        *res_size = size = sgbuf->pages * PAGE_SIZE;
  91                        break;
  92                }
  93                sgbuf->table[i].buf = tmpb.area;
  94                sgbuf->table[i].addr = tmpb.addr;
  95                sgbuf->page_table[i] = virt_to_page(tmpb.area);
  96                sgbuf->pages++;
  97        }
  98
  99        sgbuf->size = size;
 100        dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
 101        if (! dmab->area)
 102                goto _failed;
 103        return dmab->area;
 104
 105 _failed:
 106        snd_free_sgbuf_pages(dmab); /* free the table */
 107        return NULL;
 108}
 109