uapi/linux/dma-buf.h

1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
26  * struct dma_buf_sync - Synchronize with CPU access.
28  * When a DMA buffer is accessed from the CPU via mmap, it is not always
29  * possible to guarantee coherency between the CPU-visible map and underlying
35  * with DMA_BUF_SYNC_START and the appropriate read/write flags.  Once the
37  * DMA_BUF_SYNC_END and the same read/write flags.
45  * follow-up work is not submitted to GPU or other device driver until
50  * poll() on the DMA buffer file descriptor.  If the driver or API requires
52  * other synchronization primitive outside the scope of the DMA buffer API.
65 	 *     Indicates that the mapped DMA buffer will be read by the
69 	 *     Indicates that the mapped DMA buffer will be written by the
89  * struct dma_buf_export_sync_file - Get a sync_file from a dma-buf
92  * current set of fences on a dma-buf file descriptor as a sync_file.  CPU
93  * waits via poll() or other driver-specific mechanisms typically wait on
94  * whatever fences are on the dma-buf at the time the wait begins.  This
96  * dma-buf for waiting later instead of waiting immediately.  This is
98  * synchronization model but still need to inter-operate with dma-buf.
105  *  2. Submit rendering work which uses the dma-buf.  The work should wait on
109  *  3. Import the rendering-complete sync_file into the dma-buf with flags
120 	 * @flags: Read/write flags
125 	 * the returned sync file waits on any writers of the dma-buf to
130 	 * any users of the dma-buf (read or write) to complete.  Waiting
141  * struct dma_buf_import_sync_file - Insert a sync_file into a dma-buf
144  * sync_file into a dma-buf for the purposes of implicit synchronization
145  * with other dma-buf consumers.  This allows clients using explicitly
146  * synchronized APIs such as Vulkan to inter-op with dma-buf consumers
152 	 * @flags: Read/write flags
157 	 * this inserts the sync_file as a read-only fence.  Any subsequent
158 	 * implicitly synchronized writes to this dma-buf will wait on this
162 	 * write fence.  All subsequent implicitly synchronized access to
163 	 * this dma-buf will wait on this fence.