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/config.h>
  23 #include <linux/slab.h>
  24 #include <linux/mm.h>
  25 #include <linux/vmalloc.h>
  26 #include <sound/memalloc.h>
  27
  28
  29 /* table entries are align to 32 */
  30 #define SGBUF_TBL_ALIGN         32
  31 #define sgbuf_align_table(tbl)  ((((tbl) + SGBUF_TBL_ALIGN - 1) / SGBUF_TBL_ALIGN) * SGBUF_TBL_ALIGN)
  32
  33 int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
  34 {
  35         struct snd_sg_buf *sgbuf = dmab->private_data;
  36         struct snd_dma_buffer tmpb;
  37         int i;
  38
  39         if (! sgbuf)
  40                 return -EINVAL;
  41
  42         for (i = 0; i < sgbuf->pages; i++) {
  43                 tmpb.area = sgbuf->table[i].buf;
  44                 tmpb.addr = sgbuf->table[i].addr;
  45                 tmpb.bytes = PAGE_SIZE;
  46                 snd_dma_free_pages(&sgbuf->dev, &tmpb);
  47         }
  48         if (dmab->area)
  49                 vunmap(dmab->area);
  50         dmab->area = NULL;
  51
  52         if (sgbuf->table)
  53                 kfree(sgbuf->table);
  54         if (sgbuf->page_table)
  55                 kfree(sgbuf->page_table);
  56         kfree(sgbuf);
  57         dmab->private_data = NULL;
  58
  59         return 0;
  60 }
  61
  62 void *snd_malloc_sgbuf_pages(const struct snd_dma_device *dev,
  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 = kmalloc(sizeof(*sgbuf), GFP_KERNEL);
  73         if (! sgbuf)
  74                 return NULL;
  75         memset(sgbuf, 0, sizeof(*sgbuf));
  76         sgbuf->dev = *dev;
  77         sgbuf->dev.type = SNDRV_DMA_TYPE_DEV;
  78         pages = snd_sgbuf_aligned_pages(size);
  79         sgbuf->tblsize = sgbuf_align_table(pages);
  80         sgbuf->table = kmalloc(sizeof(*sgbuf->table) * sgbuf->tblsize, GFP_KERNEL);
  81         if (! sgbuf->table)
  82                 goto _failed;
  83         memset(sgbuf->table, 0, sizeof(*sgbuf->table) * sgbuf->tblsize);
  84         sgbuf->page_table = kmalloc(sizeof(*sgbuf->page_table) * sgbuf->tblsize, GFP_KERNEL);
  85         if (! sgbuf->page_table)
  86                 goto _failed;
  87         memset(sgbuf->page_table, 0, sizeof(*sgbuf->page_table) * sgbuf->tblsize);
  88
  89         /* allocate each page */
  90         for (i = 0; i < pages; i++) {
  91                 if (snd_dma_alloc_pages(&sgbuf->dev, PAGE_SIZE, &tmpb) < 0) {
  92                         if (res_size == NULL)
  93                                 goto _failed;
  94                         *res_size = size = sgbuf->pages * PAGE_SIZE;
  95                         break;
  96                 }
  97                 sgbuf->table[i].buf = tmpb.area;
  98                 sgbuf->table[i].addr = tmpb.addr;
  99                 sgbuf->page_table[i] = virt_to_page(tmpb.area);
 100                 sgbuf->pages++;
 101         }
 102
 103         sgbuf->size = size;
 104         dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
 105         if (! dmab->area)
 106                 goto _failed;
 107         return dmab->area;
 108
 109  _failed:
 110         snd_free_sgbuf_pages(dmab); /* free the table */
 111         return NULL;
 112 }