linux-4.4.1/dma_buf_ops の履歴(No.1)

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linux-4.4.1/dma_buf_ops へ行く。
- 1 (2016-02-08 (月) 11:25:18)
- 2 (2016-02-25 (木) 11:39:11)
- 3 (2016-03-15 (火) 08:50:26)

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パス: linux-4.4.1/include/linux/dma-buf.h

FIXME: これは何？
- 説明

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実装†

/**
 * 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 *);

        /* 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);

};

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linux-4.4.1/dma_buf_ops の履歴(No.1)

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