LXR linux/sound/core/sgbuf.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Scatter-Gather buffer
   4 *
   5 *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
   6 */
   7
   8#include <linux/slab.h>
   9#include <linux/mm.h>
  10#include <linux/vmalloc.h>
  11#include <linux/export.h>
  12#include <asm/pgtable.h>
  13#include <sound/memalloc.h>
  14
  15
  16/* table entries are align to 32 */
  17#define SGBUF_TBL_ALIGN         32
  18#define sgbuf_align_table(tbl)  ALIGN((tbl), SGBUF_TBL_ALIGN)
  19
  20int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
  21{
  22        struct snd_sg_buf *sgbuf = dmab->private_data;
  23        struct snd_dma_buffer tmpb;
  24        int i;
  25
  26        if (! sgbuf)
  27                return -EINVAL;
  28
  29        vunmap(dmab->area);
  30        dmab->area = NULL;
  31
  32        tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
  33        if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG)
  34                tmpb.dev.type = SNDRV_DMA_TYPE_DEV_UC;
  35        tmpb.dev.dev = sgbuf->dev;
  36        for (i = 0; i < sgbuf->pages; i++) {
  37                if (!(sgbuf->table[i].addr & ~PAGE_MASK))
  38                        continue; /* continuous pages */
  39                tmpb.area = sgbuf->table[i].buf;
  40                tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
  41                tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
  42                snd_dma_free_pages(&tmpb);
  43        }
  44
  45        kfree(sgbuf->table);
  46        kfree(sgbuf->page_table);
  47        kfree(sgbuf);
  48        dmab->private_data = NULL;
  49        
  50        return 0;
  51}
  52
  53#define MAX_ALLOC_PAGES         32
  54
  55void *snd_malloc_sgbuf_pages(struct device *device,
  56                             size_t size, struct snd_dma_buffer *dmab,
  57                             size_t *res_size)
  58{
  59        struct snd_sg_buf *sgbuf;
  60        unsigned int i, pages, chunk, maxpages;
  61        struct snd_dma_buffer tmpb;
  62        struct snd_sg_page *table;
  63        struct page **pgtable;
  64        int type = SNDRV_DMA_TYPE_DEV;
  65        pgprot_t prot = PAGE_KERNEL;
  66
  67        dmab->area = NULL;
  68        dmab->addr = 0;
  69        dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
  70        if (! sgbuf)
  71                return NULL;
  72        if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG) {
  73                type = SNDRV_DMA_TYPE_DEV_UC;
  74#ifdef pgprot_noncached
  75                prot = pgprot_noncached(PAGE_KERNEL);
  76#endif
  77        }
  78        sgbuf->dev = device;
  79        pages = snd_sgbuf_aligned_pages(size);
  80        sgbuf->tblsize = sgbuf_align_table(pages);
  81        table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
  82        if (!table)
  83                goto _failed;
  84        sgbuf->table = table;
  85        pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
  86        if (!pgtable)
  87                goto _failed;
  88        sgbuf->page_table = pgtable;
  89
  90        /* allocate pages */
  91        maxpages = MAX_ALLOC_PAGES;
  92        while (pages > 0) {
  93                chunk = pages;
  94                /* don't be too eager to take a huge chunk */
  95                if (chunk > maxpages)
  96                        chunk = maxpages;
  97                chunk <<= PAGE_SHIFT;
  98                if (snd_dma_alloc_pages_fallback(type, device,
  99                                                 chunk, &tmpb) < 0) {
 100                        if (!sgbuf->pages)
 101                                goto _failed;
 102                        if (!res_size)
 103                                goto _failed;
 104                        size = sgbuf->pages * PAGE_SIZE;
 105                        break;
 106                }
 107                chunk = tmpb.bytes >> PAGE_SHIFT;
 108                for (i = 0; i < chunk; i++) {
 109                        table->buf = tmpb.area;
 110                        table->addr = tmpb.addr;
 111                        if (!i)
 112                                table->addr |= chunk; /* mark head */
 113                        table++;
 114                        *pgtable++ = virt_to_page(tmpb.area);
 115                        tmpb.area += PAGE_SIZE;
 116                        tmpb.addr += PAGE_SIZE;
 117                }
 118                sgbuf->pages += chunk;
 119                pages -= chunk;
 120                if (chunk < maxpages)
 121                        maxpages = chunk;
 122        }
 123
 124        sgbuf->size = size;
 125        dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, prot);
 126        if (! dmab->area)
 127                goto _failed;
 128        if (res_size)
 129                *res_size = sgbuf->size;
 130        return dmab->area;
 131
 132 _failed:
 133        snd_free_sgbuf_pages(dmab); /* free the table */
 134        return NULL;
 135}
 136
 137/*
 138 * compute the max chunk size with continuous pages on sg-buffer
 139 */
 140unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
 141                                      unsigned int ofs, unsigned int size)
 142{
 143        struct snd_sg_buf *sg = dmab->private_data;
 144        unsigned int start, end, pg;
 145
 146        start = ofs >> PAGE_SHIFT;
 147        end = (ofs + size - 1) >> PAGE_SHIFT;
 148        /* check page continuity */
 149        pg = sg->table[start].addr >> PAGE_SHIFT;
 150        for (;;) {
 151                start++;
 152                if (start > end)
 153                        break;
 154                pg++;
 155                if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
 156                        return (start << PAGE_SHIFT) - ofs;
 157        }
 158        /* ok, all on continuous pages */
 159        return size;
 160}
 161EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);
 162