*参照元 [#o8dada66] #backlinks *説明 [#r658aab4] -パス: [[linux-4.4.1/include/linux/dma-buf.h]] -FIXME: これは何? --説明 **参考 [#vf5b7b45] *実装 [#u4a291b9] /** * struct dma_buf_ops - operations possible on struct dma_buf * @attach: [optional] allows different devices to 'attach' themselves to the * given buffer. It might return -EBUSY to signal that backing storage * is already allocated and incompatible with the requirements * of requesting device. * @detach: [optional] detach a given device from this buffer. * @map_dma_buf: returns list of scatter pages allocated, increases usecount * of the buffer. Requires atleast one attach to be called * before. Returned sg list should already be mapped into * _device_ address space. This call may sleep. May also return * -EINTR. Should return -EINVAL if attach hasn't been called yet. * @unmap_dma_buf: decreases usecount of buffer, might deallocate scatter * pages. * @release: release this buffer; to be called after the last dma_buf_put. * @begin_cpu_access: [optional] called before cpu access to invalidate cpu * caches and allocate backing storage (if not yet done) * respectively pin the objet into memory. * @end_cpu_access: [optional] called after cpu access to flush caches. * @kmap_atomic: maps a page from the buffer into kernel address * space, users may not block until the subsequent unmap call. * This callback must not sleep. * @kunmap_atomic: [optional] unmaps a atomically mapped page from the buffer. * This Callback must not sleep. * @kmap: maps a page from the buffer into kernel address space. * @kunmap: [optional] unmaps a page from the buffer. * @mmap: used to expose the backing storage to userspace. Note that the * mapping needs to be coherent - if the exporter doesn't directly * support this, it needs to fake coherency by shooting down any ptes * when transitioning away from the cpu domain. * @vmap: [optional] creates a virtual mapping for the buffer into kernel * address space. Same restrictions as for vmap and friends apply. * @vunmap: [optional] unmaps a vmap from the buffer */ struct dma_buf_ops { int (*attach)(struct dma_buf *, struct device *, struct dma_buf_attachment *); void (*detach)(struct dma_buf *, struct dma_buf_attachment *); - --[[linux-4.4.1/dma_buf]] --[[linux-4.4.1/device]] --[[linux-4.4.1/dma_buf_attachment]] /* For {map,unmap}_dma_buf below, any specific buffer attributes * required should get added to device_dma_parameters accessible * via dev->dma_params. */ struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *, enum dma_data_direction); void (*unmap_dma_buf)(struct dma_buf_attachment *, struct sg_table *, enum dma_data_direction); /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY * if the call would block. */ - --[[linux-4.4.1/dma_data_direction]] --[[linux-4.4.1/sg_table]] /* after final dma_buf_put() */ void (*release)(struct dma_buf *); int (*begin_cpu_access)(struct dma_buf *, size_t, size_t, enum dma_data_direction); void (*end_cpu_access)(struct dma_buf *, size_t, size_t, enum dma_data_direction); - void *(*kmap_atomic)(struct dma_buf *, unsigned long); void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *); void *(*kmap)(struct dma_buf *, unsigned long); void (*kunmap)(struct dma_buf *, unsigned long, void *); - int (*mmap)(struct dma_buf *, struct vm_area_struct *vma); void *(*vmap)(struct dma_buf *); void (*vunmap)(struct dma_buf *, void *vaddr); - }; *コメント [#uead091b]