blob: 72145646857eec5fe0fb757e65c2cf835016e324 [file] [log] [blame]
* lib/dma-noop.c
* Simple DMA noop-ops that map 1:1 with memory
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
static void *dma_noop_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
struct dma_attrs *attrs)
void *ret;
ret = (void *)__get_free_pages(gfp, get_order(size));
if (ret)
*dma_handle = virt_to_phys(ret);
return ret;
static void dma_noop_free(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr,
struct dma_attrs *attrs)
free_pages((unsigned long)cpu_addr, get_order(size));
static dma_addr_t dma_noop_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
struct dma_attrs *attrs)
return page_to_phys(page) + offset;
static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
enum dma_data_direction dir, struct dma_attrs *attrs)
int i;
struct scatterlist *sg;
for_each_sg(sgl, sg, nents, i) {
void *va;
va = sg_virt(sg);
sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va);
sg_dma_len(sg) = sg->length;
return nents;
static int dma_noop_mapping_error(struct device *dev, dma_addr_t dma_addr)
return 0;
static int dma_noop_supported(struct device *dev, u64 mask)
return 1;
struct dma_map_ops dma_noop_ops = {
.alloc = dma_noop_alloc,
.free = dma_noop_free,
.map_page = dma_noop_map_page,
.map_sg = dma_noop_map_sg,
.mapping_error = dma_noop_mapping_error,
.dma_supported = dma_noop_supported,