IDT PCI Express 89HPES32NT24xG2, User Manual, Page: 107 / 744

IDT Switch Partition and Port Configuration
PES32NT24xG2 User Manual 5 - 7 January 30, 2013
Notes
Regardless of a port’s operating mode, all registers in all functions of the port remain accessible via the
switch’s global address space, via the SMBus slave interface, or via serial EEPROM (see Chapter 19,
Register Organization). In addition, proprietary port registers (refer to section Proprietary Port-Specific
Registers in the PCI-to-PCI Bridge Function on page 19-11) continue to have effect on the operation of the
port.
Proprietary port registers are mapped to the PCI-to-PCI bridge function’s configuration space. For port
operating modes in which the PCI-to-PCI bridge function is not present in the port, the proprietary port
registers in this function are only accessible via the switch’s global address space and continue to affect the
operation of the port.
Disabled
A port that is disabled is considered unused and is placed in a low power state. For example, the port
does not generate power management messages, INTx or MSI interrupts, error messages, etc. A port in
the disabled mode has the following behavior.
– All output signals associated with the port are placed in a negated state (e.g., link status and hot-
plug signals).
The negated value of PxAIN, PxILOCKP, PxPEP, PxPIN, and PxRSTN is determined as shown in Table
11.2. PxACTIVEN and PxLINKUPN are negated. All input signals associated with the port are ignored and
have no effect on the operation of the device. The state of the following hot-plug input signals is ignored:
PxAPN, PxMRLN, PxPDN, PxPFN, and PxPWRGDN.
Boot configuration vector signals are sampled during a switch fundamental reset and thus their dynamic
state has no effect on the operating mode of the port in any port mode. For example, if the PxyMERGEN
signal associated with the port was asserted during a switch fundamental reset, then the port remains
merged while disabled.
Port Operating Mode Port Functions
Disabled None.
Unattached Function 0: PCI-to-PCI bridge,
but only responds to accesses
to the GASAADDR and GAS-
ADATA registers (see section
Unattached on page 5-8).
Upstream switch port Function 0: PCI-to-PCI bridge
Downstream switch port Function 0: PCI-to-PCI bridge
Upstream switch port with DMA Function 0: PCI-to-PCI bridge
Function 2: DMA
Upstream switch port with NT Function 0: PCI-to-PCI bridge
Function 1: NT
Upstream switch port with NT and
DMA Function 0: PCI-to-PCI bridge
Function 1: NT
Function 2: DMA
NT function Function 0: NT
NT with DMA function Function 0: NT
Function 2: DMA
Table 5.1 Port Functions for Each Port Operating Mode