From 5ea3b1b2f8ad9162684431ce6188102ca4c64b7a Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Wed, 4 Jun 2014 16:06:54 -0700 Subject: cma: add placement specifier for "cma=" kernel parameter Currently, "cma=" kernel parameter is used to specify the size of CMA, but we can't specify where it is located. We want to locate CMA below 4GB for devices only supporting 32-bit addressing on 64-bit systems without iommu. This enables to specify the placement of CMA by extending "cma=" kernel parameter. Examples: 1. locate 64MB CMA below 4GB by "cma=64M@0-4G" 2. locate 64MB CMA exact at 512MB by "cma=64M@512M" Note that the DMA contiguous memory allocator on x86 assumes that page_address() works for the pages to allocate. So this change requires to limit end address of contiguous memory area upto max_pfn_mapped to prevent from locating it on highmem area by the argument of dma_contiguous_reserve(). Signed-off-by: Akinobu Mita Cc: Marek Szyprowski Cc: Konrad Rzeszutek Wilk Cc: David Woodhouse Cc: Don Dutile Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Andi Kleen Cc: Yinghai Lu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/dma-contiguous.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h index 3b28f937d959..772eab5d524a 100644 --- a/include/linux/dma-contiguous.h +++ b/include/linux/dma-contiguous.h @@ -88,7 +88,8 @@ static inline void dma_contiguous_set_default(struct cma *cma) void dma_contiguous_reserve(phys_addr_t addr_limit); int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, - phys_addr_t limit, struct cma **res_cma); + phys_addr_t limit, struct cma **res_cma, + bool fixed); /** * dma_declare_contiguous() - reserve area for contiguous memory handling @@ -108,7 +109,7 @@ static inline int dma_declare_contiguous(struct device *dev, phys_addr_t size, { struct cma *cma; int ret; - ret = dma_contiguous_reserve_area(size, base, limit, &cma); + ret = dma_contiguous_reserve_area(size, base, limit, &cma, true); if (ret == 0) dev_set_cma_area(dev, cma); @@ -136,7 +137,9 @@ static inline void dma_contiguous_set_default(struct cma *cma) { } static inline void dma_contiguous_reserve(phys_addr_t limit) { } static inline int dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, - phys_addr_t limit, struct cma **res_cma) { + phys_addr_t limit, struct cma **res_cma, + bool fixed) +{ return -ENOSYS; } -- cgit v1.2.3