Ipmi Firmware - Kontron CP6930 User Manual

Software Description

4.4 IPMI Firmware

The PPC communicates with the Peripheral Manager (PM) using the Keyboard Controller Style (KCS) inter-
face. The bootloader is able to communicate with the PM, e.g. for POST error logging purposes and fault
resilient purposes.
The memory subsystem of the PM consists of an integrated flash memory to hold the PM operation code and
integrated RAM for data. The field replaceable unit (FRU) inventory information is stored in the nonvolatile
memory on an EEPROM connected via a local I2C interface to the PM microcontroller. It is possible to store up
to 4 Kbytes within the FRU inventory information. Communication over IPMB bus to the ShMC ensures that
'post-mortem' logging information is available even if the main processor becomes disabled.
The PM provides several I2C bus connections. Two are used as the redundant IPMB bus connections to the
backplane, one for the Board Sensors and one is for local EEPROM storage.
If an IPMB bus fault or PM failure occurs, IPMB isolators are used to switch and isolate the backplane/system
IPMB bus from the faulted Hub Board. If possible, the PM activates the redundant IPMB bus to re-establish
system management communication to report the fault.
The onboard DC voltage, current, and temperature sensors are monitored by the PM microcontroller continu-
ously. The PM will log an event into the ShMC's System Event Log (SEL) if any of the thresholds are exceeded.
To increase the reliability of the Hub board management subsystem, an external watchdog supervisor for the
PM is implemented. The PM strobes the external watchdog at two-second intervals to ensure continuity of
operation of the board's management subsystem. If the PM ceases to strobe the watchdog supervisor for
more than six seconds, the watchdog isolates the PM from the IPMBs and resets the PM. The watchdog super-
visor does not reset the payload power and the restart of the PM will not affect the payload. The external
watchdog supervisor is not configurable and must not be confused with the IPMI v1.5 watchdog timer com-
mands.
This external watchdog of the PM is implemented in a second microcontroller. This Firmware Upgrade Man-
ager (FUM) is responsible for monitoring the PM and for managing the PM fail safe firmware upgrade pro-
cess. The FUM keeps two PM Firmware code images in two external SEEPROM memories. If a failure occurs
during firmware upgrade, the FUM will automatically rollback to the last known working PM firmware image.
48 CP6930 User Guide
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