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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—PCI Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Develepor’s Manual
August 2006
576
Order Number: 306262-004US
10.6.1.0.2
A PCI Target Read Received an Error Response During the AHB Read
Operation After the PCI Transfer is Complete
This scenario is possible since the AHB Master Interface does not know ahead of time
how much data the PCI Initiator will need and thus keeps generating AHB read cycles
until the Target Interface detects the end of the PCI read cycle. Due to latencies
involved in notifying the AHB Master Interface, additional AHB reads will be generated
after the read cycle completes on PCI. If an error response is received during one of
these read-ahead AHB cycles:
1. The PCI cycle completes normally with all requested data delivered to the Initiator
and no Target Abort response generated.
2. Any additional data left in the Target Read FIFO is discarded.
3. The pci_isr.AHBE CSR bit is set to a 1 to indicate that an AHB error has occurred.
10.6.1.0.3
A PCI Target Write Received an Error Response During the AHB Write
Operation
1. The AHB Master Interface terminates the write transfer.
2. Any additional data in the Target Write FIFO is read out and discarded until the last-
data marker is encountered indicating that the PCI cycle is complete.
3. Since writes are posted by the PCI Target Interface, the cycle could complete on
PCI well before the AHB write error happens. For this reason, a Target Abort
response is not generated on the PCI bus. All writes complete normally on PCI
regardless of the status of the transfer on the AHB bus.
4. The pci_isr.AHBE CSR bit is set to a 1 to indicate that an AHB error has occurred.
10.6.1.0.4
The PCI Target Interface Detected an Address Phase Parity Error During a
Target Write
1. If the transfer is longer than 1 data phase, the PCI Target Interface terminates the
cycle with a Target Abort and sets the PCI configuration Register bit pci_srcr.STA
2. If the transfer consists of just one data phase, the PCI Target Interface accepts the
transfer without signalling Target Abort but the data is discarded and no AHB write
operation is performed.
3. The PCI Configuration Register bit pci_srcr.DPE is set indicating that a parity error
has been detected.
4. If the PCI Configuration Register bit pci_srcr.SER is set, the PCI_SERR_N signal is
asserted on the bus and the pci_srcr.SSE bit is set indicating that a system error
has been signalled by this device.
10.6.1.0.5
The PCI Target Interface Detected a Data Phase Parity Error During a Target
Write
1. The PCI Target Interface tags the errored data but otherwise processes the transfer
normally, passing the data to the AHB Master.
2. The PCI Configuration Register bit pci_srcr.DPE is set to a 1. If the pci_srcr.PER bit
is set, the PCI_PERR_N signal is asserted on the PCI bus.
3. The AHB Master Interface ignores the error and processes the write transfer
normally.
10.6.1.0.6
The Initiator of a PCI Target Read Asserts PCI_PERR_N During the Transfer
1. The error indication is ignored. Handling of the error is left to the initiator of the
transfer.