2. Serial RapidIO Interface > Loss of Lane Synchronization
62
Tsi578 User Manual
June 6, 2016
Integrated Device Technology
www.idt.com
2.9.3
Hot Extraction System Notification
System designers may require confirmation of when a component is extracted. The following sections
describe the confirmation methods supported by the Tsi578.
2.9.3.1
Polling
The system can poll the PORT_OK and PORT_UNINIT bits in the
“RapidIO Port x Error and Status
for indication that the link partner is no longer present.
2.9.3.2
Interrupts and Port Writes
Interrupts and/or port writes can be implemented as part of the hot insertion and hot extraction process.
For example, while the PORT_LOCKOUT bit in the
“RapidIO Serial Port x Control CSR”
and the
LINK_INIT_NOTIFICATION bit in the
“RapidIO Port x Interrupt Status Register”
are set, interrupts
are asserted (if LINK_INIT_NOTIFICATION_EN is set in the
“RapidIO Port x Control Independent
) until the component is extracted. A port write can also be sent once whenever a link is
initialized and the port is locked out or when the port is locked out, and the link re-acquires
initialization.
2.9.3.3
Link Errors
Another notification implementation makes use of the link errors that occur when a component is
extracted. In this design, the PORT_DISABLE bit in
“RapidIO Serial Port x Control CSR”
is set to 1 by
software and the LINK_INIT_NOTIFICATION bit in
“RapidIO Port x Interrupt Status Register”
should be cleared to 0. Error notification by the LINK_INIT_NOTIFICATION_EN in the
Port x Control Independent Register”
continues to be enabled. When the component is removed, lane
synchronization and/or lane alignment is lost. The errors detected cause a port write and/or interrupt to
be sent to the system host, indicating that a component may have been extracted.
2.10
Loss of Lane Synchronization
A loss of lane synchronization (LOLS) can occur due to high error rates on a link, reset of a link
partner, or hot extraction of a link partner. This section discusses with LOLS recovery related to high
error rates on a link. For an explanation of LOLS handling due to reset of a link partner, see
“Generating a RapidIO Reset Request to a Peer Device” on page 211
. For a discussion of LOLS
handling due to hot insertion or hot extraction of a link partner, see
“Hot Insertion and Hot Extraction”
When the Tsi578 detects a LOLS, it attempts to regain synchronization and recover so that no packets
are lost, duplicated, or unnecessarily retransmitted. This is in compliance with the
RapidIO
Interconnect Specification (Revision 1.3)
. To guarantee that no packets are lost, ensure that the duration
of the packet time-to-live timer is programmed to be greater than the duration of the port’s silence
timer.
When a Tsi578 port detects LOLS, it restarts its synchronization state machine and stops its Timeout
Interval Value (TVAL) timer for expected packet and control-symbol acknowledgements. The Tsi578
port is in input-error stopped state due to errors seen on the link. For the duration of the timer, see the
TVAL field in the
“RapidIO Switch Port Link Timeout Control CSR” on page 271
. The packet
time-to-live timer is not stopped.