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// 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>
#include "memalloc_local.h"
struct snd_sg_page {
void *buf;
dma_addr_t addr;
};
struct snd_sg_buf {
int size; /* allocated byte size */
int pages; /* allocated pages */
int tblsize; /* allocated table size */
struct snd_sg_page *table; /* address table */
struct page **page_table; /* page table (for vmap/vunmap) */
struct device *dev;
};
/* table entries are align to 32 */
#define SGBUF_TBL_ALIGN 32
#define sgbuf_align_table(tbl) ALIGN((tbl), SGBUF_TBL_ALIGN)
static void snd_dma_sg_free(struct snd_dma_buffer *dmab)
{
struct snd_sg_buf *sgbuf = dmab->private_data;
struct snd_dma_buffer tmpb;
int i;
if (!sgbuf)
return;
vunmap(dmab->area);
dmab->area = NULL;
tmpb.dev.type = SNDRV_DMA_TYPE_DEV;
if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
tmpb.dev.type = SNDRV_DMA_TYPE_DEV_WC;
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;
}
#define MAX_ALLOC_PAGES 32
static void *snd_dma_sg_alloc(struct snd_dma_buffer *dmab, size_t 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;
void *area;
dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
if (!sgbuf)
return NULL;
if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG) {
type = SNDRV_DMA_TYPE_DEV_WC;
#ifdef pgprot_noncached
prot = pgprot_noncached(PAGE_KERNEL);
#endif
}
sgbuf->dev = dmab->dev.dev;
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, dmab->dev.dev,
chunk, &tmpb) < 0) {
if (!sgbuf->pages)
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;
area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, prot);
if (!area)
goto _failed;
return area;
_failed:
snd_dma_sg_free(dmab); /* free the table */
return NULL;
}
static dma_addr_t snd_dma_sg_get_addr(struct snd_dma_buffer *dmab,
size_t offset)
{
struct snd_sg_buf *sgbuf = dmab->private_data;
dma_addr_t addr;
addr = sgbuf->table[offset >> PAGE_SHIFT].addr;
addr &= ~((dma_addr_t)PAGE_SIZE - 1);
return addr + offset % PAGE_SIZE;
}
static struct page *snd_dma_sg_get_page(struct snd_dma_buffer *dmab,
size_t offset)
{
struct snd_sg_buf *sgbuf = dmab->private_data;
unsigned int idx = offset >> PAGE_SHIFT;
if (idx >= (unsigned int)sgbuf->pages)
return NULL;
return sgbuf->page_table[idx];
}
static unsigned int snd_dma_sg_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;
/* 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;
}
static int snd_dma_sg_mmap(struct snd_dma_buffer *dmab,
struct vm_area_struct *area)
{
if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
return -ENOENT; /* continue with the default mmap handler */
}
const struct snd_malloc_ops snd_dma_sg_ops = {
.alloc = snd_dma_sg_alloc,
.free = snd_dma_sg_free,
.get_addr = snd_dma_sg_get_addr,
.get_page = snd_dma_sg_get_page,
.get_chunk_size = snd_dma_sg_get_chunk_size,
.mmap = snd_dma_sg_mmap,
};
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