[RFC PATCH 4/7] firmware: arm_scmi: Add per message transport data

[Peter Hilber]

From: Igor Skalkin <igor.skalkin@xxxxxxxxxxxxxxx>

The virtio transport in this patch series can be simplified by using the
scmi_xfer tx/rx buffers for data exchange with the virtio device, and
for saving the message state. But the virtio transport requires
prepending a transport-specific header. Also, for data exchange using
virtqueues, the tx and rx buffers should not overlap.

The first step to solve the aforementioned issues is to add a
transport-specific data pointer to scmi_xfer.

Co-developed-by: Peter Hilber <peter.hilber@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Hilber <peter.hilber@xxxxxxxxxxxxxxx>
Signed-off-by: Igor Skalkin <igor.skalkin@xxxxxxxxxxxxxxx>
---
 drivers/firmware/arm_scmi/common.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 0f1540cb2d84..e3ccec954e93 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -131,6 +131,7 @@ struct scmi_msg {
  *	buffer for the rx path as we use for the tx path.
  * @done: command message transmit completion event
  * @async_done: pointer to delayed response message received event completion
+ * @extra_data: Transport-specific private data pointer
  */
 struct scmi_xfer {
 	int transfer_id;
@@ -139,6 +140,7 @@ struct scmi_xfer {
 	struct scmi_msg rx;
 	struct completion done;
 	struct completion *async_done;
+	void *extra_data;
 };
 
 void scmi_xfer_put(const struct scmi_handle *h, struct scmi_xfer *xfer);
-- 
2.25.1