diff options
| -rw-r--r-- | include/linux/dma-mapping.h | 2 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/dma-noop.c | 75 |
3 files changed, 78 insertions, 0 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 75857cd..c0b27ff 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -70,6 +70,8 @@ struct dma_map_ops { int is_phys; }; +extern struct dma_map_ops dma_noop_ops; + #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1)) #define DMA_MASK_NONE 0x0ULL diff --git a/lib/Makefile b/lib/Makefile index a7c26a4..a572b86 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -18,6 +18,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ obj-$(CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS) += usercopy.o lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o +lib-$(CONFIG_HAS_DMA) += dma-noop.o lib-y += kobject.o klist.o obj-y += lockref.o diff --git a/lib/dma-noop.c b/lib/dma-noop.c new file mode 100644 index 0000000..7214564 --- /dev/null +++ b/lib/dma-noop.c @@ -0,0 +1,75 @@ +/* + * 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; + + BUG_ON(!sg_page(sg)); + 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, +}; + +EXPORT_SYMBOL(dma_noop_ops); |
