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- #include <linux/slab.h>
- #include <linux/mm.h>
- #include <linux/vmalloc.h>
- #include <linux/export.h>
- #include <sound/memalloc.h>
- #define SGBUF_TBL_ALIGN 32
- #define sgbuf_align_table(tbl) ALIGN((tbl), SGBUF_TBL_ALIGN)
- int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
- {
- struct snd_sg_buf *sgbuf = dmab->private_data;
- struct snd_dma_buffer tmpb;
- int i;
- if (! sgbuf)
- return -EINVAL;
- vunmap(dmab->area);
- dmab->area = NULL;
- tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
- tmpb.dev.dev = sgbuf->dev;
- for (i = 0; i < sgbuf->pages; i++) {
- if (!(sgbuf->table[i].addr & ~PAGE_MASK))
- continue;
- tmpb.area = sgbuf->table[i].buf;
- tmpb.addr = sgbuf->table[i].addr & PAGE_MASK;
- tmpb.bytes = (sgbuf->table[i].addr & ~PAGE_MASK) << PAGE_SHIFT;
- snd_dma_free_pages(&tmpb);
- }
- kfree(sgbuf->table);
- kfree(sgbuf->page_table);
- kfree(sgbuf);
- dmab->private_data = NULL;
-
- return 0;
- }
- #define MAX_ALLOC_PAGES 32
- void *snd_malloc_sgbuf_pages(struct device *device,
- size_t size, struct snd_dma_buffer *dmab,
- size_t *res_size)
- {
- struct snd_sg_buf *sgbuf;
- unsigned int i, pages, chunk, maxpages;
- struct snd_dma_buffer tmpb;
- struct snd_sg_page *table;
- struct page **pgtable;
- dmab->area = NULL;
- dmab->addr = 0;
- dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
- if (! sgbuf)
- return NULL;
- sgbuf->dev = device;
- pages = snd_sgbuf_aligned_pages(size);
- sgbuf->tblsize = sgbuf_align_table(pages);
- table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
- if (!table)
- goto _failed;
- sgbuf->table = table;
- pgtable = kcalloc(sgbuf->tblsize, sizeof(*pgtable), GFP_KERNEL);
- if (!pgtable)
- goto _failed;
- sgbuf->page_table = pgtable;
-
- maxpages = MAX_ALLOC_PAGES;
- while (pages > 0) {
- chunk = pages;
-
- if (chunk > maxpages)
- chunk = maxpages;
- chunk <<= PAGE_SHIFT;
- if (snd_dma_alloc_pages_fallback(SNDRV_DMA_TYPE_DEV, device,
- chunk, &tmpb) < 0) {
- if (!sgbuf->pages)
- goto _failed;
- if (!res_size)
- goto _failed;
- size = sgbuf->pages * PAGE_SIZE;
- break;
- }
- chunk = tmpb.bytes >> PAGE_SHIFT;
- for (i = 0; i < chunk; i++) {
- table->buf = tmpb.area;
- table->addr = tmpb.addr;
- if (!i)
- table->addr |= chunk;
- table++;
- *pgtable++ = virt_to_page(tmpb.area);
- tmpb.area += PAGE_SIZE;
- tmpb.addr += PAGE_SIZE;
- }
- sgbuf->pages += chunk;
- pages -= chunk;
- if (chunk < maxpages)
- maxpages = chunk;
- }
- sgbuf->size = size;
- dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, PAGE_KERNEL);
- if (! dmab->area)
- goto _failed;
- if (res_size)
- *res_size = sgbuf->size;
- return dmab->area;
- _failed:
- snd_free_sgbuf_pages(dmab);
- return NULL;
- }
- unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
- unsigned int ofs, unsigned int size)
- {
- struct snd_sg_buf *sg = dmab->private_data;
- unsigned int start, end, pg;
- start = ofs >> PAGE_SHIFT;
- end = (ofs + size - 1) >> PAGE_SHIFT;
-
- pg = sg->table[start].addr >> PAGE_SHIFT;
- for (;;) {
- start++;
- if (start > end)
- break;
- pg++;
- if ((sg->table[start].addr >> PAGE_SHIFT) != pg)
- return (start << PAGE_SHIFT) - ofs;
- }
-
- return size;
- }
- EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);
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