Specifications

Hardware Management

IPMC watchdog

TheIPMCFPGAincludesahardwarewatchdogtimer,referredtoasWatchdog2.This

watchdogpreventsIPMChardwareorfirmwareproblemsfromimpactingtheabilityof

othermodulesinstalledinthechassistousetheIPMBbuses.

TheIPMCwatchdogisenabledbydefaultandstartsrunningassoonaspowerispresent

andtheIPMCFPGAhasloadeditsinternalflashimageintoitsinternalSRAM.Thedefault

timeoutonpower‐upis10 seconds.AftertheIPMCboot‐loaderisfinished,theIPMC

reprogramsthetimeoutfor6secondsandwillcontinuetostrobeevery2seconds.Ifa

firmwareorhardwareproblemontheIPMCcausesittostopstrobingthewatchdogtimer

intheIPMCFPGA,theIPMCisautomaticallyisolatedfromtheIPMB‐A,IPMB‐B,andIPMB‐

Lbusessotheyremainfunctionalfortheremainingbladesinthechassisandthenresets

theIPMC.

Corrupt flash detection watchdog

TheCorruptFlashDetection(CFD)watchdogisasoftware‐basedwatchdogthatallowsthe

CPMtorecoverwhentheprimarySPIflashiseitherblankorthebootblockiscorrupted.

TheCFDwatchdogisimplementedintheIPMCandiscontrolledbytheCPU.Thesystem

BIOSmustsendanIPMIcommandtodisablethewatchdogwithin30 secondstoprevent

thetimerfromexpiring.

TheCFDwatchdogtimer isstartedanytimearesetisassertedtothepayloadprocessor

(payloadcoldreset,pushbuttonreset,oranyotherreset).Responsibilityisthenpassedto

thesystemBIOStodisablethetimer.Ifthetimerisnotdisabledbeforeitexpires,andthe

previousreset(ifoneexists)wasacoldresetorapower‐onreset,thentheIPMCfirmware

disablespa yloadpower,selectsthe secondarySPIflash,thenenablespayloadpowerto

bootfromthesecondarySPIflash.Ifthetimerisnotdisabledbeforeitexpires,thenthe

IPMCfirmwareassertsandde‐assertscoldreset.

BMC watchdog

TheBMCwatchdog,referredtoasWD1,isaprogrammablewatchdogthattriggersa

configurableactionifafaultconditioninthesystempreventstheCPUfromfeedingor

disablingthetimerwithintheprogrammedtimeinterval.

TheBMCwatchdogisimplementedintheIPMC,andcanbeconfiguredordisabled

by

standardIPMIv1.5commands.Itsprogrammablerangeisfrom10 msto6,553,600msin

100 msintervals.TheBIOSusesthiswatchdogtoimplementthePOSTwatchdogandOS

loadwatchdog.Thetimeoutperiodandtimeoutactionforthesewatchdogsis

configurablethroughtheBIOSsetupmenu.