2. Serial RapidIO Interface > Error Management
58
Tsi576 User Manual
June 6, 2016
Integrated Device Technology
www.idt.com
2.8.1
Software Assisted Error Recovery
The software-assisted error recovery process is described in terms of the ackIDs of a Tsi576 port
connected to a link partner that becomes mismatched. A system host
1
, which can be local or remote to
the Tsi576 switch, has access to the device through another port. The system host can be any processor
in a system that is tasked with error management responsibility. In a large system, multiple processors
may have this responsibility. The link partner is assumed to be register compliant to the
RapidIO
Interconnect Specification (Revision 1.3)
. All transactions between the system host and the Tsi576
switch are maintenance transactions.
If an ackID mismatch occurs between a Tsi576 switch port and an endpoint, the system host
manipulates registers in the Tsi576 switch port connected to the endpoint to perform error recovery. If
this occurs, the following software-assisted error recovery process can be used:
1.
The system host sets the PORT_LOCKOUT bit in the Tsi576’s
“RapidIO Serial Port x Control
in order to flush the port’s ingress and egress buffers. The PORT_LOCKOUT
must be asserted for 50 microseconds to guarantee that all packets are flushed.
2.
The system host writes and clears the PORT_LOCKOUT bit on in order to perform a maintenance
transaction to the link partner.
3.
The system host reads the Tsi576’s
“RapidIO Serial Port x Local ackID Status CSR” on page 278
and makes note of the inbound, outbound, and outstanding ACK_IDs.
4.
The system host instructs the Tsi576 to generate a link request to its link partner using the
“RapidIO Serial Port x Link Maintenance Request CSR” on page 275
.
5.
The system host reads the link partner's response in the Tsi576's
Maintenance Response CSR” on page 277
6.
The system host sets the switch's outbound ACK_ID value to match the value in the
ACK_ID_STAT field of the
“RapidIO Serial Port x Link Maintenance Response CSR” on
. The ACK_ID_STAT indicates the link partner's next expected ACK_ID.
7.
The system host sends a maintenance write with a priority 2 to the link partner. The maintenance
write updates the link partner’s ACK_ID status register with a new OUTBOUND value that
matches the Tsi576’s INBOUND value, and an INBOUND value which is incremented by 1
compared to the value returned in step 5. The values must be updated before the link partner sends
its maintenance response so the response has the correct ACK_ID.
— If the link partner's implementation is such that the ackID is not updated before the
maintenance response is issued, the SEMP must wait until the transaction times out (through
the TVAL timer), re-issue the link request and compare again the Tsi576 port's
Serial Port x Local ackID Status CSR” on page 278
x Link Maintenance Response CSR” on page 277
.
— The SEMP should send another link request from the Tsi576 to verify that the ACK_IDs are
the same.
1. This type of system host is sometimes referred to as a System Error Management Processor (SEMP).
Before, during, and at the conclusion of the process, monitor and clear any error bits that were
set in the
“RapidIO Port x Error and Status CSR” on page 280
.
