IDT 89HPES16NT2, User Manual

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IDT Switch Operation
PES16NT2 User Manual 4 - 7 April 15, 2008
Notes Port arbitration should never be configured to starve a port. If a port arbitration table configuration
results in port starvation, then TLPs generated by the port may be dropped (e.g., error messages, inter-
rupts, configuration completions, etc.).
The following events received by the switch core from the upstream port are treated as Unsupported
Requests (UR), and for non-posted transactions, result in a Unsupported Request (UR) completion being
returned to the upstream port.
– Reception of a CfgRd0 or CfgWr0 TLP. All CfgRd0 and CfgWr0 TLPs should have been received
and processed by the upstream stack. Therefore, the upstream stack should never pass a CfgRd0
or CfgWr0 to the switch core.
– Reception of a CfgRd1 or CfgWr1 TLP that is transformed into a CfgRd0 or CfgWr0 TLP destined
to the link partner of a downstream port and in which the device number is non-zero (covers condi-
tion outlined in PCIe base 1.0a Section 7.3.1). The device number must be zero in CfgRd0 and
CfgWr0 transactions to a downstream link partner.
– Reception of Msg or MsgD TLPs with route by address routing prior to initialization of the PCI-PCI
bridge. Prior to initialization of the PCI-PCI bridge, no transactions should be routed to the switch
core.
– Reception of route by address TLPs whose address matches an upstream port’s memory or I/O
base/limit pair and does not match a downstream ports’ memory or I/O base/limit pair. TLPs that
have no route (i.e., not destined for any upstream or downstream port) should be treated as
unsupported requests.
– Reception of route by address TLPs destined to the upstream port. There are no route by address
TLPs that should have been destined to the upstream port since the upstream port does not
process these types of TLPs.
– Reception of TLPs that have no route (i.e., do not match an address or ID route through the
switch). TLPs that have no route should be treated as unsupported requests.
– Reception of a TLP destined to a disabled downstream port (link down or MAE/IOAE bit cleared
in PA_PCICMD register). TLPs destined to a disabled downstream port should be treated as
unsupported requests.
– Reception of a TLP that matches a VGA region and the VGA Enable (VGAEN) bit is set in the
upstream port but the TLP does not map to either downstream port (i.e., VGAEN is cleared in both
downstream ports and the transaction does not map to any of the base/limit pairs associated with
the downstream ports).
The following events received by the switch core from the downstream ports are treated as Unsupported
Requests (UR) and for non-posted transactions, result in a Unsupported Request (UR) completion to be
returned to the port on which the TLP was received.
– Reception of Msg or MsgD TLPs with route by address routing prior to initialization of the PCI-PCI
bridge. Prior to initialization of the PCI-PCI bridge, no transactions should be routed to the switch
core.
– Reception of Msg or MsgD TLPs with route by ID to the PCI-PCI bridge primary bus number after
bus enumeration has completed. There are no entities that generate accept messages on the
virtual PCI bus within the switch (i.e., the primary bus number).
– Reception of route by address TLPs whose address matches an upstream port’s memory or I/O
base/limit pair and does not match a downstream ports’ memory or I/O base/limit pair. TLPs that
have no route (i.e., not destined for any upstream or downstream port) should be treated as
unsupported requests.
– Reception of TLPs that have no route (i.e., do not match an address or ID route through the
switch). TLPs that have no route should be treated as unsupported requests.
– Reception of any configuration TLP. Configuration requests can only be generated by the root and
received on the upstream port in either mode or external endpoint of the non-transparent bridge
in non-transparent mode.
– Reception of a route by ID TLP to a port that has its primary bus number set to its secondary bus
number. Such a port is uninitialized.
– Reception of a TLP that utilizes implicit routing - broadcast from root. Such a TLP can only be
received by the upstream port.