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*参照元 [#ld0d014f] #backlinks *説明 [#b0026233] -パス: [[linux-4.4.1/include/media/videobuf2-core.h]] -FIXME: これは何？ --説明 **参考 [#i3c90cd1] -現在のところ、実装は 3つある。 --[[linux-4.4.1/vb2_dma_contig_memops(global)]] --[[linux-4.4.1/vb2_dma_sg_memops(global)]] --[[linux-4.4.1/vb2_vmalloc_memops(global)]] *実装 [#x362f2aa] /** * struct vb2_mem_ops - memory handling/memory allocator operations * @alloc: allocate video memory and, optionally, allocator private data, * return NULL on failure or a pointer to allocator private, * per-buffer data on success; the returned private structure * will then be passed as buf_priv argument to other ops in this * structure. Additional gfp_flags to use when allocating the * are also passed to this operation. These flags are from the * gfp_flags field of vb2_queue. * @put: inform the allocator that the buffer will no longer be used; * usually will result in the allocator freeing the buffer (if * no other users of this buffer are present); the buf_priv * argument is the allocator private per-buffer structure * previously returned from the alloc callback. * @get_dmabuf: acquire userspace memory for a hardware operation; used for * DMABUF memory types. * @get_userptr: acquire userspace memory for a hardware operation; used for * USERPTR memory types; vaddr is the address passed to the * videobuf layer when queuing a video buffer of USERPTR type; * should return an allocator private per-buffer structure * associated with the buffer on success, NULL on failure; * the returned private structure will then be passed as buf_priv * argument to other ops in this structure. * @put_userptr: inform the allocator that a USERPTR buffer will no longer * be used. * @attach_dmabuf: attach a shared struct dma_buf for a hardware operation; * used for DMABUF memory types; alloc_ctx is the alloc context * dbuf is the shared dma_buf; returns NULL on failure; * allocator private per-buffer structure on success; * this needs to be used for further accesses to the buffer. * @detach_dmabuf: inform the exporter of the buffer that the current DMABUF * buffer is no longer used; the buf_priv argument is the * allocator private per-buffer structure previously returned * from the attach_dmabuf callback. * @map_dmabuf: request for access to the dmabuf from allocator; the allocator * of dmabuf is informed that this driver is going to use the * dmabuf. * @unmap_dmabuf: releases access control to the dmabuf - allocator is notified * that this driver is done using the dmabuf for now. * @prepare: called every time the buffer is passed from userspace to the * driver, useful for cache synchronisation, optional. * @finish: called every time the buffer is passed back from the driver * to the userspace, also optional. * @vaddr: return a kernel virtual address to a given memory buffer * associated with the passed private structure or NULL if no * such mapping exists. * @cookie: return allocator specific cookie for a given memory buffer * associated with the passed private structure or NULL if not * available. * @num_users: return the current number of users of a memory buffer; * return 1 if the videobuf layer (or actually the driver using * it) is the only user. * @mmap: setup a userspace mapping for a given memory buffer under * the provided virtual memory region. * * Required ops for USERPTR types: get_userptr, put_userptr. * Required ops for MMAP types: alloc, put, num_users, mmap. * Required ops for read/write access types: alloc, put, num_users, vaddr. * Required ops for DMABUF types: attach_dmabuf, detach_dmabuf, map_dmabuf, * unmap_dmabuf. */ struct vb2_mem_ops { void *(*alloc)(void *alloc_ctx, unsigned long size, enum dma_data_direction dma_dir, gfp_t gfp_flags); - --[[linux-4.4.1/dma_data_direction]] --[[linux-4.4.1/gfp_t]] void (*put)(void *buf_priv); struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags); - --[[linux-4.4.1/dma_buf]] void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr, unsigned long size, enum dma_data_direction dma_dir); void (*put_userptr)(void *buf_priv); void (*prepare)(void *buf_priv); void (*finish)(void *buf_priv); void *(*attach_dmabuf)(void *alloc_ctx, struct dma_buf *dbuf, unsigned long size, enum dma_data_direction dma_dir); void (*detach_dmabuf)(void *buf_priv); int (*map_dmabuf)(void *buf_priv); void (*unmap_dmabuf)(void *buf_priv); void *(*vaddr)(void *buf_priv); void *(*cookie)(void *buf_priv); unsigned int (*num_users)(void *buf_priv); int (*mmap)(void *buf_priv, struct vm_area_struct *vma); - --[[linux-4.4.1/vm_area_struct]] }; *コメント [#a006e2bf]
