| Daniel Vetter | 868c97a | 2016-12-09 19:53:05 +0100 | [diff] [blame] | 1 | Buffer Sharing and Synchronization |
| 2 | ================================== |
| 3 | |
| 4 | The dma-buf subsystem provides the framework for sharing buffers for |
| 5 | hardware (DMA) access across multiple device drivers and subsystems, and |
| 6 | for synchronizing asynchronous hardware access. |
| 7 | |
| 8 | This is used, for example, by drm "prime" multi-GPU support, but is of |
| 9 | course not limited to GPU use cases. |
| 10 | |
| 11 | The three main components of this are: (1) dma-buf, representing a |
| 12 | sg_table and exposed to userspace as a file descriptor to allow passing |
| 13 | between devices, (2) fence, which provides a mechanism to signal when |
| 14 | one device as finished access, and (3) reservation, which manages the |
| 15 | shared or exclusive fence(s) associated with the buffer. |
| 16 | |
| 17 | Shared DMA Buffers |
| 18 | ------------------ |
| 19 | |
| 20 | .. kernel-doc:: drivers/dma-buf/dma-buf.c |
| 21 | :export: |
| 22 | |
| 23 | .. kernel-doc:: include/linux/dma-buf.h |
| 24 | :internal: |
| 25 | |
| 26 | Reservation Objects |
| 27 | ------------------- |
| 28 | |
| 29 | .. kernel-doc:: drivers/dma-buf/reservation.c |
| 30 | :doc: Reservation Object Overview |
| 31 | |
| 32 | .. kernel-doc:: drivers/dma-buf/reservation.c |
| 33 | :export: |
| 34 | |
| 35 | .. kernel-doc:: include/linux/reservation.h |
| 36 | :internal: |
| 37 | |
| 38 | DMA Fences |
| 39 | ---------- |
| 40 | |
| 41 | .. kernel-doc:: drivers/dma-buf/dma-fence.c |
| 42 | :export: |
| 43 | |
| 44 | .. kernel-doc:: include/linux/dma-fence.h |
| 45 | :internal: |
| 46 | |
| 47 | Seqno Hardware Fences |
| 48 | ~~~~~~~~~~~~~~~~~~~~~ |
| 49 | |
| 50 | .. kernel-doc:: drivers/dma-buf/seqno-fence.c |
| 51 | :export: |
| 52 | |
| 53 | .. kernel-doc:: include/linux/seqno-fence.h |
| 54 | :internal: |
| 55 | |
| 56 | DMA Fence Array |
| 57 | ~~~~~~~~~~~~~~~ |
| 58 | |
| 59 | .. kernel-doc:: drivers/dma-buf/dma-fence-array.c |
| 60 | :export: |
| 61 | |
| 62 | .. kernel-doc:: include/linux/dma-fence-array.h |
| 63 | :internal: |
| 64 | |
| 65 | DMA Fence uABI/Sync File |
| 66 | ~~~~~~~~~~~~~~~~~~~~~~~~ |
| 67 | |
| 68 | .. kernel-doc:: drivers/dma-buf/sync_file.c |
| 69 | :export: |
| 70 | |
| 71 | .. kernel-doc:: include/linux/sync_file.h |
| 72 | :internal: |
| 73 | |