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6. Event Notification > Error Stopped State Recovery 130
Tsi576 User Manual
June 6, 2016
Integrated Device Technology
www.idt.com
• Multicast
— If the multicast engine attempts to transfer a packet copy to a broadcast buffer but the buffer is
full and unable to accept the packet, the MC_TEA is asserted in the congested port's “RapidIO
Port x Interrupt Status Register” on page 328 and the timed-out packet is discarded.
— If the port specific RIO Multicast Maximum Latency timer expires per the setting in the
“RapidIO Multicast Maximum Latency Counter CSR” on page 398 , the bit in the “RapidIO
Broadcast Buffer Maximum Latency Expired Error Register” on page 386 is asserted
indicating which outbound buffer was unable to accept packets and caused the timer to expire.
All packets in the broadcast buffer which were unable to make forward progress are discarded.
6.4 Error Stopped State Recovery
This section describes how to clear physical layer error conditions and status. The standard RapidIO
error recovery mechanism is sufficient in normal operation to recover from errors, however in the
following special cases software intervention is required for software recovery:
• Link partner reset error
• Hot Swap errors
• Power-up sequence errors
When a link enters a error stopped state, there are multiple ways to clear the error conditions. However,
the method described in this section uses IDT specific functionality and control symbols to clear the
errors by forcing a hardware recovery situation through software.
6.4.1 Error Stopped States
An Input Error-stopped state is entered when a RapidIO receiver detects a protocol error. When in an
Input Error-stopped state, a port processes control symbols but discards packets. An output
Error-stopped state is entered when a RapidIO transmitter is notified that one of the RapidIO receivers
on the link has detected a protocol error.
The standard error recovery mechanism for resuming communication is for the port in output
error-stopped state to transmit a link-request/input-status control symbol to its link partner. The link
partner, which should be in input error-stopped state, sends a link-response control symbol. If the link
request/response sequence is repeated four times unsuccessfully, then the port requires software
intervention to recover.
6.4.1.1 Input Error-stopped State
In an Input Error Stopped State, all received packets are discarded. Control symbols are still processed
when the link is in an Input Error Stopped State. An Input Error Stopped State is entered when an input
port detects an invalid character or any valid character other then A, K, or R in an idle sequence or an
Stype1 control symbol protocol error.
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Using IDT specific functionality and control symbols to clear errors means that sending of
maintenance transactions across the link, and dealing with the resulting time-outs, is not
required.