Merge branch 'for-linus-for-3.6-rc1' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping (6f51f515) · Commits · 戴 / test

Documentation/DMA-attributes.txt

+42 −0

Original line number	Diff line number	Diff line
		@@ -49,3 +49,45 @@ DMA_ATTR_NON_CONSISTENT lets the platform to choose to return either
		consistent or non-consistent memory as it sees fit. By using this API,
		you are guaranteeing to the platform that you have all the correct and
		necessary sync points for this memory in the driver.

		DMA_ATTR_NO_KERNEL_MAPPING
		--------------------------

		DMA_ATTR_NO_KERNEL_MAPPING lets the platform to avoid creating a kernel
		virtual mapping for the allocated buffer. On some architectures creating
		such mapping is non-trivial task and consumes very limited resources
		(like kernel virtual address space or dma consistent address space).
		Buffers allocated with this attribute can be only passed to user space
		by calling dma_mmap_attrs(). By using this API, you are guaranteeing
		that you won't dereference the pointer returned by dma_alloc_attr(). You
		can threat it as a cookie that must be passed to dma_mmap_attrs() and
		dma_free_attrs(). Make sure that both of these also get this attribute
		set on each call.

		Since it is optional for platforms to implement
		DMA_ATTR_NO_KERNEL_MAPPING, those that do not will simply ignore the
		attribute and exhibit default behavior.

		DMA_ATTR_SKIP_CPU_SYNC
		----------------------

		By default dma_map_{single,page,sg} functions family transfer a given
		buffer from CPU domain to device domain. Some advanced use cases might
		require sharing a buffer between more than one device. This requires
		having a mapping created separately for each device and is usually
		performed by calling dma_map_{single,page,sg} function more than once
		for the given buffer with device pointer to each device taking part in
		the buffer sharing. The first call transfers a buffer from 'CPU' domain
		to 'device' domain, what synchronizes CPU caches for the given region
		(usually it means that the cache has been flushed or invalidated
		depending on the dma direction). However, next calls to
		dma_map_{single,page,sg}() for other devices will perform exactly the
		same sychronization operation on the CPU cache. CPU cache sychronization
		might be a time consuming operation, especially if the buffers are
		large, so it is highly recommended to avoid it if possible.
		DMA_ATTR_SKIP_CPU_SYNC allows platform code to skip synchronization of
		the CPU cache for the given buffer assuming that it has been already
		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!

Documentation/kernel-parameters.txt

+1 −1

Original line number	Diff line number	Diff line
		@@ -526,7 +526,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.

		coherent_pool=nn[KMG] [ARM,KNL]
		Sets the size of memory pool for coherent, atomic dma
		allocations if Contiguous Memory Allocator (CMA) is used.
		allocations, by default set to 256K.

		code_bytes [X86] How many bytes of object code to print
		in an oops report.

arch/arm/common/dmabounce.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -452,6 +452,7 @@ static struct dma_map_ops dmabounce_ops = {
		.alloc = arm_dma_alloc,
		.free = arm_dma_free,
		.mmap = arm_dma_mmap,
		.get_sgtable = arm_dma_get_sgtable,
		.map_page = dmabounce_map_page,
		.unmap_page = dmabounce_unmap_page,
		.sync_single_for_cpu = dmabounce_sync_for_cpu,

arch/arm/include/asm/dma-mapping.h

+4 −20

Original line number	Diff line number	Diff line
		@@ -186,17 +186,6 @@ extern int arm_dma_mmap(struct device dev, struct vm_area_struct vma,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		struct dma_attrs *attrs);

		#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, NULL)

		static inline int dma_mmap_attrs(struct device dev, struct vm_area_struct vma,
		void *cpu_addr, dma_addr_t dma_addr,
		size_t size, struct dma_attrs *attrs)
		{
		struct dma_map_ops *ops = get_dma_ops(dev);
		BUG_ON(!ops);
		return ops->mmap(dev, vma, cpu_addr, dma_addr, size, attrs);
		}

		static inline void dma_alloc_writecombine(struct device dev, size_t size,
		dma_addr_t *dma_handle, gfp_t flag)
		{
		@@ -213,20 +202,12 @@ static inline void dma_free_writecombine(struct device *dev, size_t size,
		return dma_free_attrs(dev, size, cpu_addr, dma_handle, &attrs);
		}

		static inline int dma_mmap_writecombine(struct device dev, struct vm_area_struct vma,
		void *cpu_addr, dma_addr_t dma_addr, size_t size)
		{
		DEFINE_DMA_ATTRS(attrs);
		dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
		return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
		}

		/*
		* This can be called during boot to increase the size of the consistent
		* DMA region above it's default value of 2MB. It must be called before the
		* memory allocator is initialised, i.e. before any core_initcall.
		*/
		extern void __init init_consistent_dma_size(unsigned long size);
		static inline void init_consistent_dma_size(unsigned long size) { }

		/*
		* For SA-1111, IXP425, and ADI systems the dma-mapping functions are "magic"
		@@ -280,6 +261,9 @@ extern void arm_dma_sync_sg_for_cpu(struct device , struct scatterlist , int,
		enum dma_data_direction);
		extern void arm_dma_sync_sg_for_device(struct device , struct scatterlist , int,
		enum dma_data_direction);
		extern int arm_dma_get_sgtable(struct device dev, struct sg_table sgt,
		void *cpu_addr, dma_addr_t dma_addr, size_t size,
		struct dma_attrs *attrs);

		#endif /* __KERNEL__ */
		#endif

arch/arm/mm/dma-mapping.c

+227 −334

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