In an effort to modernize the documentation for dma api, move the api explanation to kernel-doc comment in the source code and use the kernel-doc here in the documentation. Signed-off-by: anish kumar <yesanishhere@xxxxxxxxx> --- Documentation/core-api/dma-api.rst | 66 ++++++------------------------ 1 file changed, 12 insertions(+), 54 deletions(-) diff --git a/Documentation/core-api/dma-api.rst b/Documentation/core-api/dma-api.rst index 8e3cce3d0a23..8e89f328ba54 100644 --- a/Documentation/core-api/dma-api.rst +++ b/Documentation/core-api/dma-api.rst @@ -86,65 +86,23 @@ not __get_free_pages(). Also, they understand common hardware constraints for alignment, like queue heads needing to be aligned on N-byte boundaries. -:: - - struct dma_pool * - dma_pool_create(const char *name, struct device *dev, - size_t size, size_t align, size_t alloc); - -dma_pool_create() initializes a pool of DMA-coherent buffers -for use with a given device. It must be called in a context which -can sleep. - -The "name" is for diagnostics (like a struct kmem_cache name); dev and size -are like what you'd pass to dma_alloc_coherent(). The device's hardware -alignment requirement for this type of data is "align" (which is expressed -in bytes, and must be a power of two). If your device has no boundary -crossing restrictions, pass 0 for alloc; passing 4096 says memory allocated -from this pool must not cross 4KByte boundaries. - -:: - - void * - dma_pool_zalloc(struct dma_pool *pool, gfp_t mem_flags, - dma_addr_t *handle) - -Wraps dma_pool_alloc() and also zeroes the returned memory if the -allocation attempt succeeded. - +.. kernel-doc:: mm/dmapool.c + :identifiers: dma_pool_create -:: - - void * - dma_pool_alloc(struct dma_pool *pool, gfp_t gfp_flags, - dma_addr_t *dma_handle); - -This allocates memory from the pool; the returned memory will meet the -size and alignment requirements specified at creation time. Pass -GFP_ATOMIC to prevent blocking, or if it's permitted (not -in_interrupt, not holding SMP locks), pass GFP_KERNEL to allow -blocking. Like dma_alloc_coherent(), this returns two values: an -address usable by the CPU, and the DMA address usable by the pool's -device. - -:: +.. kernel-doc:: mm/dmapool.c + :identifiers: dma_pool_alloc - void - dma_pool_free(struct dma_pool *pool, void *vaddr, - dma_addr_t addr); +dma_pool_zalloc wraps dma_pool_alloc() and also zeroes the returned memory +if the allocation attempt succeeded. -This puts memory back into the pool. The pool is what was passed to -dma_pool_alloc(); the CPU (vaddr) and DMA addresses are what -were returned when that routine allocated the memory being freed. +.. kernel-doc:: mm/dmapool.c + :identifiers: dma_pool_create -:: - - void - dma_pool_destroy(struct dma_pool *pool); +.. kernel-doc:: mm/dmapool.c + :identifiers: dma_pool_free -dma_pool_destroy() frees the resources of the pool. It must be -called in a context which can sleep. Make sure you've freed all allocated -memory back to the pool before you destroy it. +.. kernel-doc:: mm/dmapool.c + :identifiers: dma_pool_destroy Part Ic - DMA addressing limitations -- 2.39.5 (Apple Git-154)
