diff options
| -rw-r--r-- | Documentation/DMA-API.txt | 22 | ||||
| -rw-r--r-- | include/linux/dma-mapping.h | 36 |
2 files changed, 53 insertions, 5 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index 1d26eeb6b5f6..6b20128fab8a 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -277,14 +277,26 @@ and <size> parameters are provided to do partial page mapping, it is recommended that you never use these unless you really know what the cache width is. +dma_addr_t +dma_map_resource(struct device *dev, phys_addr_t phys_addr, size_t size, + enum dma_data_direction dir, unsigned long attrs) + +void +dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size, + enum dma_data_direction dir, unsigned long attrs) + +API for mapping and unmapping for MMIO resources. All the notes and +warnings for the other mapping APIs apply here. The API should only be +used to map device MMIO resources, mapping of RAM is not permitted. + int dma_mapping_error(struct device *dev, dma_addr_t dma_addr) -In some circumstances dma_map_single() and dma_map_page() will fail to create -a mapping. A driver can check for these errors by testing the returned -DMA address with dma_mapping_error(). A non-zero return value means the mapping -could not be created and the driver should take appropriate action (e.g. -reduce current DMA mapping usage or delay and try again later). +In some circumstances dma_map_single(), dma_map_page() and dma_map_resource() +will fail to create a mapping. A driver can check for these errors by testing +the returned DMA address with dma_mapping_error(). A non-zero return value +means the mapping could not be created and the driver should take appropriate +action (e.g. reduce current DMA mapping usage or delay and try again later). int dma_map_sg(struct device *dev, struct scatterlist *sg, diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 673b7be85f7a..6e00c7fdbbd3 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -264,6 +264,42 @@ static inline void dma_unmap_page(struct device *dev, dma_addr_t addr, debug_dma_unmap_page(dev, addr, size, dir, false); } +static inline dma_addr_t dma_map_resource(struct device *dev, + phys_addr_t phys_addr, + size_t size, + enum dma_data_direction dir, + unsigned long attrs) +{ + struct dma_map_ops *ops = get_dma_ops(dev); + unsigned long pfn = __phys_to_pfn(phys_addr); + dma_addr_t addr; + + BUG_ON(!valid_dma_direction(dir)); + + /* Don't allow RAM to be mapped */ + BUG_ON(pfn_valid(pfn)); + + addr = phys_addr; + if (ops->map_resource) + addr = ops->map_resource(dev, phys_addr, size, dir, attrs); + + debug_dma_map_resource(dev, phys_addr, size, dir, addr); + + return addr; +} + +static inline void dma_unmap_resource(struct device *dev, dma_addr_t addr, + size_t size, enum dma_data_direction dir, + unsigned long attrs) +{ + struct dma_map_ops *ops = get_dma_ops(dev); + + BUG_ON(!valid_dma_direction(dir)); + if (ops->unmap_resource) + ops->unmap_resource(dev, addr, size, dir, attrs); + debug_dma_unmap_resource(dev, addr, size, dir); +} + static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size, enum dma_data_direction dir) |