diff options
Diffstat (limited to 'sound/core/sgbuf.c')
| -rw-r--r-- | sound/core/sgbuf.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c new file mode 100644 index 000000000..29ddb7618 --- /dev/null +++ b/sound/core/sgbuf.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Scatter-Gather buffer + * + * Copyright (c) by Takashi Iwai <tiwai@suse.de> + */ + +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/vmalloc.h> +#include <linux/export.h> +#include <sound/memalloc.h> + + +/* table entries are align to 32 */ +#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; + if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG) + tmpb.dev.type = SNDRV_DMA_TYPE_DEV_UC; + tmpb.dev.dev = sgbuf->dev; + for (i = 0; i < sgbuf->pages; i++) { + if (!(sgbuf->table[i].addr & ~PAGE_MASK)) + continue; /* continuous pages */ + 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; + int type = SNDRV_DMA_TYPE_DEV; + pgprot_t prot = PAGE_KERNEL; + + dmab->area = NULL; + dmab->addr = 0; + dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL); + if (! sgbuf) + return NULL; + if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG) { + type = SNDRV_DMA_TYPE_DEV_UC; +#ifdef pgprot_noncached + prot = pgprot_noncached(PAGE_KERNEL); +#endif + } + 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; + + /* allocate pages */ + maxpages = MAX_ALLOC_PAGES; + while (pages > 0) { + chunk = pages; + /* don't be too eager to take a huge chunk */ + if (chunk > maxpages) + chunk = maxpages; + chunk <<= PAGE_SHIFT; + if (snd_dma_alloc_pages_fallback(type, 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; /* mark head */ + 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, prot); + if (! dmab->area) + goto _failed; + if (res_size) + *res_size = sgbuf->size; + return dmab->area; + + _failed: + snd_free_sgbuf_pages(dmab); /* free the table */ + return NULL; +} + +/* + * compute the max chunk size with continuous pages on sg-buffer + */ +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; + + if (!sg) + return size; + + start = ofs >> PAGE_SHIFT; + end = (ofs + size - 1) >> PAGE_SHIFT; + /* check page continuity */ + 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; + } + /* ok, all on continuous pages */ + return size; +} +EXPORT_SYMBOL(snd_sgbuf_get_chunk_size); |