From efc42bc98058a36d761b16a114823db1a902ed05 Mon Sep 17 00:00:00 2001 From: Tomasz Stanislawski Date: Mon, 18 Jun 2012 09:25:01 +0200 Subject: scatterlist: add sg_alloc_table_from_pages function This patch adds a new constructor for an sg table. The table is constructed from an array of struct pages. All contiguous chunks of the pages are merged into a single sg nodes. A user may provide an offset and a size of a buffer if the buffer is not page-aligned. The function is dedicated for DMABUF exporters which often perform conversion from an page array to a scatterlist. Moreover the scatterlist should be squashed in order to save memory and to speed-up the process of DMA mapping using dma_map_sg. The code is based on the patch 'v4l: vb2-dma-contig: add support for scatterlist in userptr mode' and hints from Laurent Pinchart. Signed-off-by: Tomasz Stanislawski Signed-off-by: Kyungmin Park Acked-by: Daniel Vetter Acked-by: Laurent Pinchart Signed-off-by: Marek Szyprowski CC: Andrew Morton --- include/linux/scatterlist.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index ac9586dadfa5..7b600da9a635 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -214,6 +214,10 @@ void sg_free_table(struct sg_table *); int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, gfp_t, sg_alloc_fn *); int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); +int sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, unsigned int n_pages, + unsigned long offset, unsigned long size, + gfp_t gfp_mask); size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen); -- cgit v1.2.3 From 5e6cafc83e30f0f70c79a2b7aef237dc57e29f02 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Fri, 13 Apr 2012 12:32:09 +0200 Subject: mm: vmalloc: use const void * for caller argument 'const void *' is a safer type for caller function type. This patch updates all references to caller function type. Signed-off-by: Marek Szyprowski Reviewed-by: Kyungmin Park Reviewed-by: Minchan Kim --- include/linux/vmalloc.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index dcdfc2bda922..2e28f4d40d7f 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -32,7 +32,7 @@ struct vm_struct { struct page **pages; unsigned int nr_pages; phys_addr_t phys_addr; - void *caller; + const void *caller; }; /* @@ -62,7 +62,7 @@ extern void *vmalloc_32_user(unsigned long size); extern void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot); extern void *__vmalloc_node_range(unsigned long size, unsigned long align, unsigned long start, unsigned long end, gfp_t gfp_mask, - pgprot_t prot, int node, void *caller); + pgprot_t prot, int node, const void *caller); extern void vfree(const void *addr); extern void *vmap(struct page **pages, unsigned int count, @@ -85,13 +85,13 @@ static inline size_t get_vm_area_size(const struct vm_struct *area) extern struct vm_struct *get_vm_area(unsigned long size, unsigned long flags); extern struct vm_struct *get_vm_area_caller(unsigned long size, - unsigned long flags, void *caller); + unsigned long flags, const void *caller); extern struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags, unsigned long start, unsigned long end); extern struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags, unsigned long start, unsigned long end, - void *caller); + const void *caller); extern struct vm_struct *remove_vm_area(const void *addr); extern int map_vm_area(struct vm_struct *area, pgprot_t prot, -- cgit v1.2.3 From e9da6e9905e639b0f842a244bc770b48ad0523e9 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Mon, 30 Jul 2012 09:11:33 +0200 Subject: ARM: dma-mapping: remove custom consistent dma region This patch changes dma-mapping subsystem to use generic vmalloc areas for all consistent dma allocations. This increases the total size limit of the consistent allocations and removes platform hacks and a lot of duplicated code. Atomic allocations are served from special pool preallocated on boot, because vmalloc areas cannot be reliably created in atomic context. Signed-off-by: Marek Szyprowski Reviewed-by: Kyungmin Park Reviewed-by: Minchan Kim --- include/linux/vmalloc.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 2e28f4d40d7f..6071e911c7f4 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -93,6 +93,7 @@ extern struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long start, unsigned long end, const void *caller); extern struct vm_struct *remove_vm_area(const void *addr); +extern struct vm_struct *find_vm_area(const void *addr); extern int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages); -- cgit v1.2.3 From d5724f172fd1406c6962c4d2e27228b8e9e83642 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Wed, 16 May 2012 15:20:37 +0200 Subject: common: DMA-mapping: add DMA_ATTR_NO_KERNEL_MAPPING attribute This patch adds DMA_ATTR_NO_KERNEL_MAPPING attribute which 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(). Signed-off-by: Marek Szyprowski Reviewed-by: Kyungmin Park Reviewed-by: Daniel Vetter --- include/linux/dma-attrs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h index 547ab568d3ae..a37c10cc51c5 100644 --- a/include/linux/dma-attrs.h +++ b/include/linux/dma-attrs.h @@ -15,6 +15,7 @@ enum dma_attr { DMA_ATTR_WEAK_ORDERING, DMA_ATTR_WRITE_COMBINE, DMA_ATTR_NON_CONSISTENT, + DMA_ATTR_NO_KERNEL_MAPPING, DMA_ATTR_MAX, }; -- cgit v1.2.3 From d2b7428eb0caa7c66e34b6ac869a43915b294123 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Wed, 13 Jun 2012 10:05:52 +0200 Subject: common: dma-mapping: introduce dma_get_sgtable() function This patch adds dma_get_sgtable() function which is required to let drivers to share the buffers allocated by DMA-mapping subsystem. Right now the driver gets a dma address of the allocated buffer and the kernel virtual mapping for it. If it wants to share it with other device (= map into its dma address space) it usually hacks around kernel virtual addresses to get pointers to pages or assumes that both devices share the DMA address space. Both solutions are just hacks for the special cases, which should be avoided in the final version of buffer sharing. To solve this issue in a generic way, a new call to DMA mapping has been introduced - dma_get_sgtable(). It allocates a scatter-list which describes the allocated buffer and lets the driver(s) to use it with other device(s) by calling dma_map_sg() on it. This patch provides a generic implementation based on virt_to_page() call. Architectures which require more sophisticated translation might provide their own get_sgtable() methods. Signed-off-by: Marek Szyprowski Reviewed-by: Kyungmin Park Reviewed-by: Daniel Vetter --- include/linux/dma-mapping.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index dfc099e56a66..94af41858513 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -18,6 +18,9 @@ struct dma_map_ops { int (*mmap)(struct device *, struct vm_area_struct *, void *, dma_addr_t, size_t, struct dma_attrs *attrs); + int (*get_sgtable)(struct device *dev, struct sg_table *sgt, void *, + dma_addr_t, size_t, struct dma_attrs *attrs); + dma_addr_t (*map_page)(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir, -- cgit v1.2.3 From bdf5e4871f1b41150236e2337837399109469e65 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Wed, 6 Jun 2012 14:46:44 +0200 Subject: common: DMA-mapping: add DMA_ATTR_SKIP_CPU_SYNC attribute This patch adds DMA_ATTR_SKIP_CPU_SYNC attribute to the DMA-mapping subsystem. 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! Signed-off-by: Marek Szyprowski Reviewed-by: Kyungmin Park --- include/linux/dma-attrs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/dma-attrs.h b/include/linux/dma-attrs.h index a37c10cc51c5..f83f793223ff 100644 --- a/include/linux/dma-attrs.h +++ b/include/linux/dma-attrs.h @@ -16,6 +16,7 @@ enum dma_attr { DMA_ATTR_WRITE_COMBINE, DMA_ATTR_NON_CONSISTENT, DMA_ATTR_NO_KERNEL_MAPPING, + DMA_ATTR_SKIP_CPU_SYNC, DMA_ATTR_MAX, }; -- cgit v1.2.3