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habanalabs: define uAPI to export FD for DMA-BUF

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User process might want to share the device memory with another
driver/device, and to allow it to access it over PCIe (P2P).

To enable this, we utilize the dma-buf mechanism and add a dma-buf
exporter support, so the other driver can import the device memory and
access it.

The device memory is allocated using our existing allocation uAPI,
where the user will get a handle that represents the allocation.

The user will then need to call the new
uAPI (HL_MEM_OP_EXPORT_DMABUF_FD) and give the handle as a parameter.

The driver will return a FD that represents the DMA-BUF object that
was created to match that allocation.

Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Reviewed-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Oded Gabbay 2021-04-11 08:26:50 +03:00
parent 81f8582ec4
commit a9498ee575
1 changed files with 27 additions and 1 deletions
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28
include/uapi/misc/habanalabs.h
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@ -960,6 +960,10 @@ union hl_wait_cs_args {
#define HL_MEM_OP_UNMAP 3
/* Opcode to map a hw block */
#define HL_MEM_OP_MAP_BLOCK 4
/* Opcode to create DMA-BUF object for an existing device memory allocation
* and to export an FD of that DMA-BUF back to the caller
*/
#define HL_MEM_OP_EXPORT_DMABUF_FD 5
/* Memory flags */
#define HL_MEM_CONTIGUOUS 0x1
@ -1031,11 +1035,26 @@ struct hl_mem_in {
/* Virtual address returned from HL_MEM_OP_MAP */
__u64 device_virt_addr;
} unmap;
/* HL_MEM_OP_EXPORT_DMABUF_FD */
struct {
/* Handle returned from HL_MEM_OP_ALLOC. In Gaudi,
* where we don't have MMU for the device memory, the
* driver expects a physical address (instead of
* a handle) in the device memory space.
*/
__u64 handle;
/* Size of memory allocation. Relevant only for GAUDI */
__u64 mem_size;
} export_dmabuf_fd;
};
/* HL_MEM_OP_* */
__u32 op;
/* HL_MEM_* flags */
/* HL_MEM_* flags.
* For the HL_MEM_OP_EXPORT_DMABUF_FD opcode, this field holds the
* DMA-BUF file/FD flags.
*/
__u32 flags;
/* Context ID - Currently not in use */
__u32 ctx_id;
@ -1072,6 +1091,13 @@ struct hl_mem_out {
__u32 pad;
};
/* Returned in HL_MEM_OP_EXPORT_DMABUF_FD. Represents the
* DMA-BUF object that was created to describe a memory
* allocation on the device's memory space. The FD should be
* passed to the importer driver
*/
__s32 fd;
};
};