linux/sound/core/sgbuf.c
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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
  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        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
  61void *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}
 108