Add a function to the dma_buf_attach_ops to indicate whether the connection is a private interconnect. If so the function returns the address to an interconnect-defined structure that can be used for further negotiating.
Also add a field to the dma_buf_attachment that indicates whether a private interconnect is used by the attachment. Signed-off-by: Thomas Hellström <[email protected]> --- include/linux/dma-buf.h | 51 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index d58e329ac0e7..25dbf1fea09a 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -442,6 +442,39 @@ struct dma_buf { #endif }; +/* RFC: Separate header for the interconnect defines? */ + +/** + * struct dma_buf_interconnect - Private interconnect + * @name: The name of the interconnect + */ +struct dma_buf_interconnect { + const char *name; +}; + +/** + * struct dma_buf_interconnect_attach_ops - Interconnect attach ops base-class + * + * Declared for type-safety. Interconnect implementations should subclass to + * implement negotiation-specific ops. + */ +struct dma_buf_interconnect_attach_ops { +}; + +/** + * struct dma_buf_interconnect_attach - Interconnect state + * @interconnect: The struct dma_buf_interconnect identifying the interconnect + * + * Interconnect implementations subclass as needed for attachment state + * that can't be stored elsewhere. It could, for example, hold a pointer + * to a replacement of the sg-list after the attachment has been mapped. + * If no additional state is needed, an exporter could define a single + * static instance of this struct. + */ +struct dma_buf_interconnect_attach { + const struct dma_buf_interconnect *interconnect; +}; + /** * struct dma_buf_attach_ops - importer operations for an attachment * @@ -475,6 +508,21 @@ struct dma_buf_attach_ops { * point to the new location of the DMA-buf. */ void (*move_notify)(struct dma_buf_attachment *attach); + + /** + * @supports_interconnect: [optional] - Does the driver support a local interconnect? + * + * Does the importer support a private interconnect? The interconnect is + * identified using a unique address defined instantiated either by the driver + * if the interconnect is driver-private or globally + * (RFC added to the dma-buf-interconnect.c file) if cross-driver. + * + * Return: A pointer to the interconnect-private attach_ops structure if supported, + * %NULL otherwise. + */ + const struct dma_buf_interconnect_attach_ops * + (*supports_interconnect)(struct dma_buf_attachment *attach, + const struct dma_buf_interconnect *interconnect); }; /** @@ -484,6 +532,8 @@ struct dma_buf_attach_ops { * @node: list of dma_buf_attachment, protected by dma_resv lock of the dmabuf. * @peer2peer: true if the importer can handle peer resources without pages. * @priv: exporter specific attachment data. + * @interconnect_attach: Private interconnect state for the connection if used, + * NULL otherwise. * @importer_ops: importer operations for this attachment, if provided * dma_buf_map/unmap_attachment() must be called with the dma_resv lock held. * @importer_priv: importer specific attachment data. @@ -503,6 +553,7 @@ struct dma_buf_attachment { struct list_head node; bool peer2peer; const struct dma_buf_attach_ops *importer_ops; + struct dma_buf_interconnect_attach *interconnect_attach; void *importer_priv; void *priv; }; -- 2.51.0
