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
  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                 if (!(sgbuf->table[i].addr & ~PAGE_MASK))
  45                         continue; /* continuous pages */
  46                 tmpb.area = sgbuf->table[i].buf;
  47                 tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
  48                 tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
  49                 snd_dma_free_pages(&tmpb);
  50         }
  51         if (dmab->area)
  52                 vunmap(dmab->area);
  53         dmab->area = NULL;
  54
  55         kfree(sgbuf->table);
  56         kfree(sgbuf->page_table);
  57         kfree(sgbuf);
  58         dmab->private_data = NULL;
  59
  60         return 0;
  61 }
  62
  63 #define MAX_ALLOC_PAGES         32
  64
  65 void *snd_malloc_sgbuf_pages(struct device *device,
  66                              size_t size, struct snd_dma_buffer *dmab,
  67                              size_t *res_size)
  68 {
  69         struct snd_sg_buf *sgbuf;
  70         unsigned int i, pages, chunk, maxpages;
  71         struct snd_dma_buffer tmpb;
  72         struct snd_sg_page *table;
  73         struct page **pgtable;
  74
  75         dmab->area = NULL;
  76         dmab->addr = 0;
  77         dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
  78         if (! sgbuf)
  79                 return NULL;
  80         sgbuf->dev = device;
  81         pages = snd_sgbuf_aligned_pages(size);
  82         sgbuf->tblsize = sgbuf_align_table(pages);
  83         table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
  84         if (!table)
  85                 goto _failed;
  86         sgbuf->table = table;
  87         pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
  88         if (!pgtable)
  89                 goto _failed;
  90         sgbuf->page_table = pgtable;
  91
  92         /* allocate pages */
  93         maxpages = MAX_ALLOC_PAGES;
  94         while (pages > 0) {
  95                 chunk = pages;
  96                 /* don't be too eager to take a huge chunk */
  97                 if (chunk > maxpages)
  98                         chunk = maxpages;
  99                 chunk <<= PAGE_SHIFT;
 100                 if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV, device,
 101                                                  chunk, &tmpb) < 0) {
 102                         if (!sgbuf->pages)
 103                                 return NULL;
 104                         if (!res_size)
 105                                 goto _failed;
 106                         size = sgbuf->pages * PAGE_SIZE;
 107                         break;
 108                 }
 109                 chunk = tmpb.bytes >> PAGE_SHIFT;
 110                 for (i = 0; i < chunk; i++) {
 111                         table->buf = tmpb.area;
 112                         table->addr = tmpb.addr;
 113                         if (!i)
 114                                 table->addr |= chunk; /* mark head */
 115                         table++;
 116                         *pgtable++ = virt_to_page(tmpb.area);
 117                         tmpb.area += PAGE_SIZE;
 118                         tmpb.addr += PAGE_SIZE;
 119                 }
 120                 sgbuf->pages += chunk;
 121                 pages -= chunk;
 122                 if (chunk < maxpages)
 123                         maxpages = chunk;
 124         }
 125
 126         sgbuf->size = size;
 127         dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
 128         if (! dmab->area)
 129                 goto _failed;
 130         if (res_size)
 131                 *res_size = sgbuf->size;
 132         return dmab->area;
 133
 134  _failed:
 135         snd_free_sgbuf_pages(dmab); /* free the table */
 136         return NULL;
 137 }