IDT PCI Express 89HPES32NT24xG2, User Manual, Page: 326 / 744

IDT Switch Events
PES32NT24xG2 User Manual 16 - 2 January 30, 2013
Notes
register controls which partitions are notified of the occurrence of an event. As mentioned above, each
partition’s upstream port functions (i.e., PCI-to-PCI bridge and/or NT) may be configured to generate an
interrupt to the system when an event is signaled to the partition.
– When a switch event is signaled to multiple partitions and the corresponding interrupts are gener-
ated, interrupt handling software running in the root-complex of each partition can determine the
cause of the interrupt by probing the interrupt status register in the partition’s upstream port func-
tion (i.e., P2PINTSTS register in the PCI-to-PCI bridge function or NTINTSTS register in the NT
function). From probing this register, the interrupt handler can determine if the interrupt was
caused by a switch event. Furthermore, the exact event that caused the interrupt can be deter-
mined by probing the SESTS register.
– In order to re-arm the interrupt mechanism due to switch events, such software needs to clear the
Switch Event (SEVENT) bit in the P2PINTSTS or NTINTSTS register. In addition, it is recom-
mended that a switch manager device in charge of configuring the event signaling mechanism
also be signaled of the occurrence of the event (e.g., by connecting the switch manager to a switch
partition’s upstream port), so that the switch manager can re-arm the event signaling mechanism
by clearing the appropriate status bits in the event status registers (e.g., SELINKUPSTS,
SELINKDNSTS, SEFRSTSTS, etc., described in the following sections).
Figure 16.1 Switch Event Detection and Signaling Mechanism
Link Up
A link up event occurs when a port’s data link status transitions from DL_Down to DL_Up state. Refer to
section Link States on page 7-9 for a details on the conditions for which the data link reports DL_Down and
DL_Up status.
Associated with each port of the switch is a status bit in the Switch Event Link Up Status (SELINK-
UPSTS) register. A bit in the status register is set when a link up event occurs on the corresponding port.
Partition 0
Event
Signaling
to partition
Switch
Link Up
Event
Detection
SESTS Register
SEMSK Register
SEPMSK Register
Partition 1 Partition 7
Link Down
Event
Detection
Failover
Event
Detection
Registers that
control Switch
Event Signaling
Event
Signaling
to partition Event
Signaling
to partition