blob: dcd4df1f71746c293f8914bca2654a911f34ffe3 [file] [log] [blame]
* 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) {
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,