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Notes
PES48H12G2 User Manual
®
Introduction
The PES48H12G2 supports up to 12 active switch partitions. Each switch partition represents an inde-
pendent PCI Express hierarchy whose operation is independent of other switch partitions.
A port may be configured to operate in one of four modes.
– Disabled port
– Downstream switch port
– Upstream switch port
– Unattached
The operating mode of a switch port may be dynamically reconfigured without affecting in any way unre-
lated switch partitions.
Switch Partitions
A switch partition represents a logical container to which ports are attached. Each switch partition has an
associated ID. The PES48H12G2 supports 12 switch partitions with IDs 0 through 11. A port is attached to
a switch partition by setting the Switch Partition (SWPART) field in the corresponding Switch Port x Control
(SWPORTxCTL) register to the ID of the partition to which the port should be attached and configuring the
port to be in one of the following modes.
– Downstream switch port
– Upstream switch port
A port in a disabled or unattached mode is not associated with a switch partition. In these modes, the
behavior of a port is unaffected by the state of any partition.
Partition Configuration
The following list represents valid switch partition configurations. The behavior of all other configurations
is undefined.
– A switch partition with no associated ports
– A switch partition with one upstream port and zero or more downstream ports
– A switch partition with no upstream port and one or more downstream ports
An upstream port is a port configured to operate in upstream switch port mode and is attached to the
partition. The Upstream Port (US) bit is set in the Switch Partition Status (SWPARTxSTS) register when
there is an upstream port associated with the partition. When the US bit is set in the SWPARTxSTS register,
the Upstream Port ID (USID) field contains the port ID of the upstream port of the partition.
A downstream port is a port configured to operate in downstream switch port mode and attached to the
partition. A switch partition with no associated ports represents a logical entity. The state and configuration
of such a partition has no functional effect on the operation of the device.
A switch partition with one upstream switch port and zero or more downstream ports represents a stan-
dard PCI express switch configuration. Such a configuration operates as a standard PCI express switch
using the associated ports.
Switch Partitions
6 - 1
Chapter 6
April 5, 2013
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