73 строки
1.6 KiB
C
73 строки
1.6 KiB
C
/*
|
|
* lib/dma-virt.c
|
|
*
|
|
* DMA operations that map to virtual addresses without flushing memory.
|
|
*/
|
|
#include <linux/export.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/dma-mapping.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, 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;
|
|
}
|
|
|
|
static int dma_virt_mapping_error(struct device *dev, dma_addr_t dma_addr)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static int dma_virt_supported(struct device *dev, u64 mask)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
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,
|
|
.mapping_error = dma_virt_mapping_error,
|
|
.dma_supported = dma_virt_supported,
|
|
};
|
|
EXPORT_SYMBOL(dma_virt_ops);
|