From 4b9347dcbe3b426d19bda99b2061a2d1fe5a2dce Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Mon, 15 Oct 2012 16:03:51 +0200 Subject: [PATCH] common: DMA-mapping: add DMA_ATTR_FORCE_CONTIGUOUS attribute This patch adds DMA_ATTR_FORCE_CONTIGUOUS attribute to the DMA-mapping subsystem. By default DMA-mapping subsystem is allowed to assemble the buffer allocated by dma_alloc_attrs() function from individual pages if it can be mapped as contiguous chunk into device dma address space. By specifing this attribute the allocated buffer is forced to be contiguous also in physical memory. Signed-off-by: Marek Szyprowski --- Documentation/DMA-attributes.txt | 9 +++++++++ include/linux/dma-attrs.h | 1 + 2 files changed, 10 insertions(+) diff --git a/Documentation/DMA-attributes.txt b/Documentation/DMA-attributes.txt index f50309081ac7..e59480db9ee0 100644 --- a/Documentation/DMA-attributes.txt +++ b/Documentation/DMA-attributes.txt @@ -91,3 +91,12 @@ transferred to 'device' domain. This attribute can be also used for dma_unmap_{single,page,sg} functions family to force buffer to stay in device domain after releasing a mapping for it. Use this attribute with care! + +DMA_ATTR_FORCE_CONTIGUOUS +------------------------- + +By default DMA-mapping subsystem is allowed to assemble the buffer +allocated by dma_alloc_attrs() function from individual pages if it can +be mapped as contiguous chunk into device dma address space. By +specifing this attribute the allocated buffer is forced to be contiguous +also in physical memory. diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h index f83f793223ff..c8e1831d7572 100644 --- a/include/linux/dma-attrs.h +++ b/include/linux/dma-attrs.h @@ -17,6 +17,7 @@ enum dma_attr { DMA_ATTR_NON_CONSISTENT, DMA_ATTR_NO_KERNEL_MAPPING, DMA_ATTR_SKIP_CPU_SYNC, + DMA_ATTR_FORCE_CONTIGUOUS, DMA_ATTR_MAX, }; -- 2.20.1