To do framebuffer updates, one needs memcpy from system memory and a pointer-increment function. Add both interfaces with documentation.
v5: * include <linux/string.h> to build on sparc64 (Sam)
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Reviewed-by: Sam Ravnborg sam@ravnborg.org Tested-by: Sam Ravnborg sam@ravnborg.org --- include/linux/dma-buf-map.h | 73 ++++++++++++++++++++++++++++++++----- 1 file changed, 63 insertions(+), 10 deletions(-)
diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h index 2e8bbecb5091..583a3a1f9447 100644 --- a/include/linux/dma-buf-map.h +++ b/include/linux/dma-buf-map.h @@ -7,6 +7,7 @@ #define __DMA_BUF_MAP_H__
#include <linux/io.h> +#include <linux/string.h>
/** * DOC: overview @@ -32,6 +33,14 @@ * accessing the buffer. Use the returned instance and the helper functions * to access the buffer's memory in the correct way. * + * The type :c:type:`struct dma_buf_map <dma_buf_map>` and its helpers are + * actually independent from the dma-buf infrastructure. When sharing buffers + * among devices, drivers have to know the location of the memory to access + * the buffers in a safe way. :c:type:`struct dma_buf_map <dma_buf_map>` + * solves this problem for dma-buf and its users. If other drivers or + * sub-systems require similar functionality, the type could be generalized + * and moved to a more prominent header file. + * * Open-coding access to :c:type:`struct dma_buf_map <dma_buf_map>` is * considered bad style. Rather then accessing its fields directly, use one * of the provided helper functions, or implement your own. For example, @@ -51,6 +60,14 @@ * * dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf); * + * Instances of struct dma_buf_map do not have to be cleaned up, but + * can be cleared to NULL with dma_buf_map_clear(). Cleared mappings + * always refer to system memory. + * + * .. code-block:: c + * + * dma_buf_map_clear(&map); + * * Test if a mapping is valid with either dma_buf_map_is_set() or * dma_buf_map_is_null(). * @@ -73,17 +90,19 @@ * if (dma_buf_map_is_equal(&sys_map, &io_map)) * // always false * - * Instances of struct dma_buf_map do not have to be cleaned up, but - * can be cleared to NULL with dma_buf_map_clear(). Cleared mappings - * always refer to system memory. + * A set up instance of struct dma_buf_map can be used to access or manipulate + * the buffer memory. Depending on the location of the memory, the provided + * helpers will pick the correct operations. Data can be copied into the memory + * with dma_buf_map_memcpy_to(). The address can be manipulated with + * dma_buf_map_incr(). * - * The type :c:type:`struct dma_buf_map <dma_buf_map>` and its helpers are - * actually independent from the dma-buf infrastructure. When sharing buffers - * among devices, drivers have to know the location of the memory to access - * the buffers in a safe way. :c:type:`struct dma_buf_map <dma_buf_map>` - * solves this problem for dma-buf and its users. If other drivers or - * sub-systems require similar functionality, the type could be generalized - * and moved to a more prominent header file. + * .. code-block:: c + * + * const void *src = ...; // source buffer + * size_t len = ...; // length of src + * + * dma_buf_map_memcpy_to(&map, src, len); + * dma_buf_map_incr(&map, len); // go to first byte after the memcpy */
/** @@ -210,4 +229,38 @@ static inline void dma_buf_map_clear(struct dma_buf_map *map) } }
+/** + * dma_buf_map_memcpy_to - Memcpy into dma-buf mapping + * @dst: The dma-buf mapping structure + * @src: The source buffer + * @len: The number of byte in src + * + * Copies data into a dma-buf mapping. The source buffer is in system + * memory. Depending on the buffer's location, the helper picks the correct + * method of accessing the memory. + */ +static inline void dma_buf_map_memcpy_to(struct dma_buf_map *dst, const void *src, size_t len) +{ + if (dst->is_iomem) + memcpy_toio(dst->vaddr_iomem, src, len); + else + memcpy(dst->vaddr, src, len); +} + +/** + * dma_buf_map_incr - Increments the address stored in a dma-buf mapping + * @map: The dma-buf mapping structure + * @incr: The number of bytes to increment + * + * Increments the address stored in a dma-buf mapping. Depending on the + * buffer's location, the correct value will be updated. + */ +static inline void dma_buf_map_incr(struct dma_buf_map *map, size_t incr) +{ + if (map->is_iomem) + map->vaddr_iomem += incr; + else + map->vaddr += incr; +} + #endif /* __DMA_BUF_MAP_H__ */