tree 5b864244cb1448534b7dfb60d2bc2433121c63d0
parent edebe169ebefd6410d74850bbce1ea599c347753
author Christian Geddes <crgeddes@us.ibm.com> 1630508065 -0500
committer crgeddes <crgeddes@us.ibm.com> 1630986542 +0000

Notify remote endpoint with RX_COMPLETE prior to handling MCTP packet

This change ensures that prior to handling the contents of the
MCTP packet we get, we notify the the remote endpoint that we
have read the contents of the transmission they sent us.

Prior to this change, if the RX buffer contained a packet with the EOM
bit set, the packet is upgraded to a message and is passed to whatever
function the message_rx callback is bound to. In Hostboot's case this
causes a message to be sent to a message queue the PLDM requester
is blocked on. In some cases, we saw the PLDM requester thread get woken
up by this message, process the response, and fire off another PLDM
message, all prior to the task managing the MCTP rx waking back up to
send the RX_COMPLETE message to the KCS data register. We saw if the
TX_STARTED command for the next packet was written prior to Hostboot
writing the RX_COMPLETE from reading the last packet that, the message
that Hostboot sent would not make it to PLDM on the BMC.

Signed-off-by: Christian Geddes <crgeddes@us.ibm.com>
Change-Id: I9f3ecc0d504e22ef69999835c68a9abb033c48dd