Altera Cyclone V User Manual page 124

12–4
Table 12–4. Errors Detected by the Transaction Layer (Part 2 of 3)
Error
Completion timeout
(1)
Completer abort
Unexpected completion
(1)
Receiver overflow
Flow control protocol error
(1)
(FCPE)
Malformed TLP
Cyclone V Hard IP for PCI Express
Type
This error occurs when a request originating from the Application Layer
does not generate a corresponding completion TLP within the
Uncorrectable established time. It is the responsibility of the Application Layer logic to
(non-fatal) provide the completion timeout mechanism. The completion timeout
should be reported from the Transaction Layer using the cpl_err[0]
signal.
Uncorrectable The Application Layer reports this error using the cpl_err[2]signal
(non-fatal) when it aborts receipt of a TLP.
This error is caused by an unexpected completion transaction. The Hard
IP block handles the following conditions:
The Requester ID in the completion packet does not match the
■
Configured ID of the Endpoint.
The completion packet has an invalid tag number. (Typically, the tag
■
used in the completion packet exceeds the number of tags specified.)
The completion packet has a tag that does not match an outstanding
■
request.
Uncorrectable
The completion packet for a request that was to I/O or Configuration
■
(non-fatal)
Space has a length greater than 1 dword.
The completion status is Configuration Retry Status (CRS) in
■
response to a request that was not to Configuration Space.
In all of the above cases, the TLP is not presented to the Application
Layer; the Hard IP block deletes it.
The Application Layer can detect and report other unexpected
completion conditions using the cpl_err[2] signal. For example, the
Application Layer can report cases where the total length of the received
successful completions do not match the original read request length.
This error occurs when a component receives a TLP that violates the FC
Uncorrectable
credits allocated for this type of TLP. In all cases the hard IP block
(fatal)
deletes the TLP and it is not presented to the Application Layer.
A receiver must never cumulatively issue more than 2047 outstanding
unused data credits or 127 header credits to the transmitter.
Uncorrectable
If Infinite credits are advertised for a particular TLP type (posted,
(fatal)
non-posted, completions) during initialization, update FC DLLPs must
continue to transmit infinite credits for that TLP type.
This error is caused by any of the following conditions:
The data payload of a received TLP exceeds the maximum payload
■
size.
The TD field is asserted but no TLP digest exists, or a TLP digest
■
exists but the TD bit of the PCI Express request header packet is not
asserted.
Uncorrectable
A TLP violates a byte enable rule. The Hard IP block checks for this
■
(fatal)
violation, which is considered optional by the PCI Express
specifications.
A TLP in which the type and length fields do not correspond with
■
the total length of the TLP.
A TLP in which the combination of format and type is not specified by
■
the PCI Express specification.
Chapter 12: Error Handling
Transaction Layer Errors
Description
November 2011 Altera Corporation