Altera Arria V Hard IP for PCI Express - Manual (Page 214)

14–4 Chapter 14: Error Handling
Transaction Layer Errors
Arria V Hard IP for PCI Express December 2013 Altera Corporation
User Guide
Completion timeout
Uncorrectable
(non-fatal)
This error occurs when a request originating from the Application Layer
does not generate a corresponding completion TLP within the
established time. It is the responsibility of the Application Layer logic to
provide the completion timeout mechanism. The completion timeout
should be reported from the Transaction Layer using the
cpl_err[0]
signal.
Completer abort (1)
Uncorrectable
(non-fatal)
The Application Layer reports this error using the cpl_err[2] signal
when it aborts receipt of a TLP.
Unexpected completion
Uncorrectable
(non-fatal)
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.
■ The completion packet for a request that was to I/O or Configuration
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.
Receiver overflow (1)
Uncorrectable
(fatal)
This error occurs when a component receives a TLP that violates the FC
credits allocated for this type of TLP. In all cases the hard IP block
deletes the TLP and it is not presented to the Application Layer.
Flow control protocol error
(FCPE)
(1)
Uncorrectable
(fatal)
This error occurs when a component does not receive update flow
control credits with the 200
μ
s limit.
Malformed TLP
Uncorrectable
(fatal)
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.
■ A TLP violates a byte enable rule. The Hard IP block checks for this
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.
Table 14–4. Errors Detected by the Transaction Layer (Part 2 of 3)
Error Type Description