diff options
| -rw-r--r-- | Documentation/core-api/dma-api.rst | 49 | ||||
| -rw-r--r-- | arch/arm/common/sa1111.c | 2 | ||||
| -rw-r--r-- | include/linux/dma-map-ops.h | 23 | ||||
| -rw-r--r-- | include/linux/dma-mapping.h | 24 | ||||
| -rw-r--r-- | kernel/dma/remap.c | 2 |
5 files changed, 68 insertions, 32 deletions
diff --git a/Documentation/core-api/dma-api.rst b/Documentation/core-api/dma-api.rst index ea0413276ddb..75cb757bbff0 100644 --- a/Documentation/core-api/dma-api.rst +++ b/Documentation/core-api/dma-api.rst @@ -519,10 +519,9 @@ routines, e.g.::: Part II - Non-coherent DMA allocations -------------------------------------- -These APIs allow to allocate pages in the kernel direct mapping that are -guaranteed to be DMA addressable. This means that unlike dma_alloc_coherent, -virt_to_page can be called on the resulting address, and the resulting -struct page can be used for everything a struct page is suitable for. +These APIs allow to allocate pages that are guaranteed to be DMA addressable +by the passed in device, but which need explicit management of memory ownership +for the kernel vs the device. If you don't understand how cache line coherency works between a processor and an I/O device, you should not be using this part of the API. @@ -537,7 +536,7 @@ an I/O device, you should not be using this part of the API. This routine allocates a region of <size> bytes of consistent memory. It returns a pointer to the allocated region (in the processor's virtual address space) or NULL if the allocation failed. The returned memory may or may not -be in the kernels direct mapping. Drivers must not call virt_to_page on +be in the kernel direct mapping. Drivers must not call virt_to_page on the returned memory region. It also returns a <dma_handle> which may be cast to an unsigned integer the @@ -565,7 +564,45 @@ reused. Free a region of memory previously allocated using dma_alloc_noncoherent(). dev, size and dma_handle and dir must all be the same as those passed into dma_alloc_noncoherent(). cpu_addr must be the virtual address returned by -the dma_alloc_noncoherent(). +dma_alloc_noncoherent(). + +:: + + struct page * + dma_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle, + enum dma_data_direction dir, gfp_t gfp) + +This routine allocates a region of <size> bytes of non-coherent memory. It +returns a pointer to first struct page for the region, or NULL if the +allocation failed. The resulting struct page can be used for everything a +struct page is suitable for. + +It also returns a <dma_handle> which may be cast to an unsigned integer the +same width as the bus and given to the device as the DMA address base of +the region. + +The dir parameter specified if data is read and/or written by the device, +see dma_map_single() for details. + +The gfp parameter allows the caller to specify the ``GFP_`` flags (see +kmalloc()) for the allocation, but rejects flags used to specify a memory +zone such as GFP_DMA or GFP_HIGHMEM. + +Before giving the memory to the device, dma_sync_single_for_device() needs +to be called, and before reading memory written by the device, +dma_sync_single_for_cpu(), just like for streaming DMA mappings that are +reused. + +:: + + void + dma_free_pages(struct device *dev, size_t size, struct page *page, + dma_addr_t dma_handle, enum dma_data_direction dir) + +Free a region of memory previously allocated using dma_alloc_pages(). +dev, size and dma_handle and dir must all be the same as those passed into +dma_alloc_noncoherent(). page must be the pointer returned by +dma_alloc_pages(). :: diff --git a/arch/arm/common/sa1111.c b/arch/arm/common/sa1111.c index c98ebae1aeac..f89c1ea327a2 100644 --- a/arch/arm/common/sa1111.c +++ b/arch/arm/common/sa1111.c @@ -22,7 +22,7 @@ #include <linux/platform_device.h> #include <linux/slab.h> #include <linux/spinlock.h> -#include <linux/dma-mapping.h> +#include <linux/dma-map-ops.h> #include <linux/clk.h> #include <linux/io.h> diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index 8029f7e04145..a5f89fc4d6df 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -203,6 +203,29 @@ static inline int dma_mmap_from_global_coherent(struct vm_area_struct *vma, } #endif /* CONFIG_DMA_DECLARE_COHERENT */ +int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, + void *cpu_addr, dma_addr_t dma_addr, size_t size, + unsigned long attrs); +int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, + void *cpu_addr, dma_addr_t dma_addr, size_t size, + unsigned long attrs); +struct page *dma_common_alloc_pages(struct device *dev, size_t size, + dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp); +void dma_common_free_pages(struct device *dev, size_t size, struct page *vaddr, + dma_addr_t dma_handle, enum dma_data_direction dir); + +struct page **dma_common_find_pages(void *cpu_addr); +void *dma_common_contiguous_remap(struct page *page, size_t size, pgprot_t prot, + const void *caller); +void *dma_common_pages_remap(struct page **pages, size_t size, pgprot_t prot, + const void *caller); +void dma_common_free_remap(void *cpu_addr, size_t size); + +struct page *dma_alloc_from_pool(struct device *dev, size_t size, + void **cpu_addr, gfp_t flags, + bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t)); +bool dma_free_from_pool(struct device *dev, void *start, size_t size); + #ifdef CONFIG_ARCH_HAS_DMA_COHERENCE_H #include <asm/dma-coherence.h> #elif defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index 3f029afdc9dc..956151052d45 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -389,30 +389,6 @@ static inline void dma_sync_sgtable_for_device(struct device *dev, #define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, 0) #define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, 0) -extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, - void *cpu_addr, dma_addr_t dma_addr, size_t size, - unsigned long attrs); -struct page *dma_common_alloc_pages(struct device *dev, size_t size, - dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp); -void dma_common_free_pages(struct device *dev, size_t size, struct page *vaddr, - dma_addr_t dma_handle, enum dma_data_direction dir); -struct page **dma_common_find_pages(void *cpu_addr); -void *dma_common_contiguous_remap(struct page *page, size_t size, - pgprot_t prot, const void *caller); - -void *dma_common_pages_remap(struct page **pages, size_t size, - pgprot_t prot, const void *caller); -void dma_common_free_remap(void *cpu_addr, size_t size); - -struct page *dma_alloc_from_pool(struct device *dev, size_t size, - void **cpu_addr, gfp_t flags, - bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t)); -bool dma_free_from_pool(struct device *dev, void *start, size_t size); - -int -dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr, - dma_addr_t dma_addr, size_t size, unsigned long attrs); - static inline void *dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp) { diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c index 78b23f089cf1..905c3fa005f1 100644 --- a/kernel/dma/remap.c +++ b/kernel/dma/remap.c @@ -2,7 +2,7 @@ /* * Copyright (c) 2014 The Linux Foundation */ -#include <linux/dma-mapping.h> +#include <linux/dma-map-ops.h> #include <linux/slab.h> #include <linux/vmalloc.h> |