mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-24 11:34:50 +08:00
0a0f0d8be7
Split out all the bits that are purely for dma_map_ops implementations and related code into a new <linux/dma-map-ops.h> header so that they don't get pulled into all the drivers. That also means the architecture specific <asm/dma-mapping.h> is not pulled in by <linux/dma-mapping.h> any more, which leads to a missing includes that were pulled in by the x86 or arm versions in a few not overly portable drivers. Signed-off-by: Christoph Hellwig <hch@lst.de>
62 lines
1.5 KiB
C
62 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* DMA operations that map to virtual addresses without flushing memory.
|
|
*/
|
|
#include <linux/export.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/dma-map-ops.h>
|
|
#include <linux/scatterlist.h>
|
|
|
|
static void *dma_virt_alloc(struct device *dev, size_t size,
|
|
dma_addr_t *dma_handle, gfp_t gfp,
|
|
unsigned long attrs)
|
|
{
|
|
void *ret;
|
|
|
|
ret = (void *)__get_free_pages(gfp | __GFP_ZERO, get_order(size));
|
|
if (ret)
|
|
*dma_handle = (uintptr_t)ret;
|
|
return ret;
|
|
}
|
|
|
|
static void dma_virt_free(struct device *dev, size_t size,
|
|
void *cpu_addr, dma_addr_t dma_addr,
|
|
unsigned long attrs)
|
|
{
|
|
free_pages((unsigned long)cpu_addr, get_order(size));
|
|
}
|
|
|
|
static dma_addr_t dma_virt_map_page(struct device *dev, struct page *page,
|
|
unsigned long offset, size_t size,
|
|
enum dma_data_direction dir,
|
|
unsigned long attrs)
|
|
{
|
|
return (uintptr_t)(page_address(page) + offset);
|
|
}
|
|
|
|
static int dma_virt_map_sg(struct device *dev, struct scatterlist *sgl,
|
|
int nents, enum dma_data_direction dir,
|
|
unsigned long attrs)
|
|
{
|
|
int i;
|
|
struct scatterlist *sg;
|
|
|
|
for_each_sg(sgl, sg, nents, i) {
|
|
BUG_ON(!sg_page(sg));
|
|
sg_dma_address(sg) = (uintptr_t)sg_virt(sg);
|
|
sg_dma_len(sg) = sg->length;
|
|
}
|
|
|
|
return nents;
|
|
}
|
|
|
|
const struct dma_map_ops dma_virt_ops = {
|
|
.alloc = dma_virt_alloc,
|
|
.free = dma_virt_free,
|
|
.map_page = dma_virt_map_page,
|
|
.map_sg = dma_virt_map_sg,
|
|
.alloc_pages = dma_common_alloc_pages,
|
|
.free_pages = dma_common_free_pages,
|
|
};
|
|
EXPORT_SYMBOL(dma_virt_ops);
|