8. Error Handling
165
PowerSpan II User Manual
80A1010_MA001_09
Integrated Device Technology
www.idt.com
The user controls the Px target propagation of PCI Master-Abort Configuration command initiated on
Py with MAC_ERR. When the Master-Abort Configuration Error Mapping (MAC_ERR) bit is set in
the
“PCI-1 Miscellaneous Control and Status Register” on page 283
, the Px target returns all ones on a
Py Configuration read that terminates with Master-Abort. When the MAC_ERR bit is cleared, the Px
target responds with Target-Abort.
A typical interrupt service routine for a PB Interface error
—
as illustrated for in
executes
the following steps:
1.
Read ISR1 to determine which interface reported the error.
2.
If the PCI-1 Interface reported the error:
•
Read error logs Px_ERRCS and Px_AERR to obtain diagnostic information.
•
Read Px_CSR to distinguish address parity, data parity, Target-Abort, Master-Abort scenarios.
3.
Clear Px_ERRCS[ES] to enable future error logging.
4.
Clear the status bit in ISR1.
Negates external interrupt pin.
5.
Clear the error bits in Px_CSR.
6.
Fix the configuration issue that caused the error.
7.
Retry the transaction that caused the error.
The flow of transactions through PowerSpan II is independent of error status bits in
“PCI-1 Control and Status Register.” on page 251
and the
Error Log Status (ES) bit in the
“PCI-1 Bus Error Control and Status Register” on page 281
.
The transaction response for a Px target error is:
•
Address parity: claim and complete as normal
•
Data parity: transaction proceeds normally to its destination
The transaction response for a Px master error is:
•
Data parity on reads
— Transaction proceeds normally to its source
— Correct data parity is calculated internally and propagated back to the source
•
Detection of Target-Abort, generation of Master-Abort, expiration of max retry counter:
— All writes:
–
Stop the transaction
–
Purge the entire source transaction from the Switching Fabric
–
DMA writes, error status sent to DMA channel registers
— All reads:
–
Stop the transaction
–
Latch error condition for propagation back to source