linux-4.4.1/ion_dma_buf_begin_cpu_access()

参照元†

linux-4.4.1/dma_buf_ops(global)

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説明†

パス: linux-4.4.1/drivers/staging/android/ion/ion.c

FIXME: これは何？
- 説明

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引数†

struct dma_buf *dmabuf
- linux-4.4.1/dma_buf
size_t start
size_t len
enum dma_data_direction direction
- linux-4.4.1/dma_data_direction

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返り値†

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参考†

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実装†

static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, size_t start,
                                        size_t len,
                                        enum dma_data_direction direction)
{
        struct ion_buffer *buffer = dmabuf->priv;
        void *vaddr;

- linux-4.4.1/ion_buffer

        if (!buffer->heap->ops->map_kernel) {
                pr_err("%s: map kernel is not implemented by this heap.\n",
                       __func__);
                return -ENODEV;
        }

buffer->heap->ops は struct ion_heap_ops * 型
- linux-4.4.1/ion_heap_ops

        mutex_lock(&buffer->lock);
        vaddr = ion_buffer_kmap_get(buffer);
        mutex_unlock(&buffer->lock);
        return PTR_ERR_OR_ZERO(vaddr);

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