Kontron AM5020 IPMI Firmware - Manual (Page 41)

AM5020 IPMI Firmware
ID 1045-0205, Rev. 1.0 Page 33
P R E L I M I N A R Y
Clock Receiver:
The PCI Express reference clock provided by the carrier may be slightly modulated (SSC -
Spread Spectrum Clock). The FRU E-Keying data for the AM5020 contains two AMC link
descriptors for each PCI Express channel, one with SSC (priority 1) or with non-SSC (priority
2). The carrier’s IPMC selects the “matching” link descriptor (SSC or non-SSC) during E-
keying using the Set AMC Port State command.
Clock Source:
When the AM5020 acts as clock source for the PCI Express reference clock, the clock signal
must be routed also to the PCI Express Endpoint. The backplane, the carrier’s IPMC or the
MCH must be capable of doing this (Clock E-Keying according to AMC.1 R2.0).
The information whether the AMC clock or the local clock is used as PCI Express reference
clock can be directly read from the board’s E-Keying clock configuration register (ICKEY0) at
address 0x297.
The DIP Switch SW3 can be used to forcibly configure the PCI Express reference clock. Please
refer to the AM5020 User Guide for details.
8. uEFI BIOS Failover Control - Automatic Flash
Selection
After each board processor reset, the MMC selects the SPI flash by applying the related non-
volatile parameter. Then it waits for a message from the uEFI BIOS. This message contains a
checksum report, i.e. it reports whether the boot flash's checksum is right or wrong.
If either the checksum is wrong or the message is not received within a given time, the currently
used uEFI BIOS is assumed to contain an invalid or a corrupted image. In this case, the MMC
toggles the related non-volatile parameter and generates a “Boot Error - Invalid boot sector”
event. The sensor event is generated either by sensor “FWH0 Boot Err” or “FWH1 Boot Err”,
depending on which uEFI BIOS bank failed.
After selecting the alternate uEFI BIOS bank, the board processor is reset and the MMC waits
for the checksum report message from uEFI BIOS again.
The number of retries depends on the error condition (no message from uEFI BIOS at all or
checksum error).
The number within the names of the two related sensors “FWH0/1 Boot Err” corresponds to the
value of the non-volatile parameter, not to the absolute number of the uEFI BIOS firmware bank
(which is not known by the MMC).