From c79095092834a18ae74cfc08def1a5a101dc106c Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Thu, 29 Dec 2011 13:09:51 +0100 Subject: ARM: integrate CMA with DMA-mapping subsystem This patch adds support for CMA to dma-mapping subsystem for ARM architecture. By default a global CMA area is used, but specific devices are allowed to have their private memory areas if required (they can be created with dma_declare_contiguous() function during board initialisation). Contiguous memory areas reserved for DMA are remapped with 2-level page tables on boot. Once a buffer is requested, a low memory kernel mapping is updated to to match requested memory access type. GFP_ATOMIC allocations are performed from special pool which is created early during boot. This way remapping page attributes is not needed on allocation time. CMA has been enabled unconditionally for ARMv6+ systems. Signed-off-by: Marek Szyprowski Signed-off-by: Kyungmin Park CC: Michal Nazarewicz Acked-by: Arnd Bergmann Tested-by: Rob Clark Tested-by: Ohad Ben-Cohen Tested-by: Benjamin Gaignard Tested-by: Robert Nelson Tested-by: Barry Song --- Documentation/kernel-parameters.txt | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'Documentation/kernel-parameters.txt') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 669e8bb..41996c6 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -520,6 +520,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. a hypervisor. Default: yes + coherent_pool=nn[KMG] [ARM,KNL] + Sets the size of memory pool for coherent, atomic dma + allocations if Contiguous Memory Allocator (CMA) is used. + code_bytes [X86] How many bytes of object code to print in an oops report. Range: 0 - 8192 -- cgit v1.1