[T10] SPL - Question on BREAK during SSP frame transmission

Srinivas Vijayaragavan Srinivas.Vijayaragavan at synopsys.com
Thu Sep 15 03:55:06 PDT 2016


Hi,

I have a question on the expected PL_PM behavior when a SSP frame transmission is interrupted by BREAKs.

The following lines are mentioned in the SPL(spl4r09) specification  -

7.2.3.4 PL_PM3:Connected state
...
If this state receives a Connection Closed (Transition to Idle) confirmation after receiving one of the following:
a) a Connection Closed (Break Received) confirmation; or
b) a Connection Closed (Break Requested) confirmation,
then this state shall send a Transmission Status (Break Received) confirmation to the transport layer.

...
If this state receives a Connection Closed (Normal) confirmation, a Connection Closed (Transition to Idle)
confirmation, or a Phy Disabled confirmation after sending a Tx Frame request but before receiving a Frame
Transmitted confirmation, then this state shall send a Retry Frame message to the PL_OC state machine.

=============================================================

I encountered a scenario where the link layer receives BREAKs after it has transmitted SOF and before EOF could be transmitted. The SL_CC state machine sends a "Connection Closed (Break Received)" confirmation first followed by a "Connection Closed (Transition to Idle)".

Both conditions mentioned above are satisfied

1)     "Connection Closed (Transition to Idle)" is received after "Connection Closed (Break Received)"

2)     "Connection Closed (Transition to Idle)" is received after sending a Tx Frame request but before receiving a Frame Transmitted confirmation

I am wondering how the same frame can have a "Transmission Status" going to transport layer and a "Retry Frame" message going to the PL_OC. The "Transmission Status (Break Received)" will cause the ST_TTS state machine to terminate the transfer; but "Retry Frame" message will cause PL_OC to retry the frame.


Am I missing something here?


Thanks,
Srinivas
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