Specifications

5
Hardware Management
52
Redundant firmware images
TheH8microcontrollerfirmwareimageiscomposedofasinglebootimageanddual
redundantapplicationimages,allphysicallystoredinthesingleinternalflashfortheH8.
Onresetorboot‐upoftheH8,thebootimagereadstheSerialEEPROMoftheIPMCentity
todeterminewhichH8bankistheactivebank.Next,thebootimagevalidatestheactive
andbackupapplicationimages.Ifthe activeapplicationimageisvalid,executionis
transferredfromthebootimagetotheactiveapplicationimage.Whentheactive
applicationimageisinvalidandthebackupimageisvalid,executionistransferredfrom
thebootimagetothebackupapplicationimage.Forsituationswherebothapplication
imagesareinvalid,thebootimageremainsincontroloftheIPMC,theOOSLEDistoggled
onceeverysecond,andtheapplicationimagesneedtobeupdated.
IftheIPMCdetectsanerrorwhileloadingtheapplicationimagefromtheactivebank,the
IPMCswitchestotheotherbankandlogsaneventintheSELaftertheotherimageis
loaded.
Fordetails,seetheeventdescriptionfortheOEMHPMEventsensoronpage 121.
Determining the active IPMC bank
YoucanusethefollowingcommandtoquerywhichbankistheactiveIPMCapplication
bank:
rsys‐ipmitoolhpmcompprop1192
Thecommandreturnstheactivebanknumber,asshownbelow.
OEMData[0]:0x01(=activebanknumber)
IPMC interface to the payload processor
ThepayloadprocessorinterfaceallowstheCPUtocommunicatewiththeIPMC.TheCPM
implementsthisinterfaceasaKCSport,whichissimilartohowaPCmotherboard
processorsendscommandstoalegacyPC‐compatiblekeyboardcontroller.TheIPMCis
connectedtothepayloadLPCbusandrespondsto
I/ObyteaddressesasaKCSinterface.
TheCPMusestheserialIRQoutputoftheIPMCtoimplementthemessaginginterruptfor
thepayload.TheIPMCusestheserialIRQoutputtogeneratealegacyinterruptIRQ6to
thepayloadprocessor.DuringuseoftheKCSinterfacebythepa yload
processor,output
bufferfull(OBF)conditionsgeneratethisinterrupttothepayloadiftheIPMIdriveronthe
payloadprocessorisininterrupt‐enabledmode.
ThesystemBIOSandtheOS‐levelcodeusethisinterfacetointeractdirectlywiththe
IPMC.WithOSpackagesthatsupportOpenIPMI,theOpenIPMIdriverandtoolsetare
availabletomakeiteasiertowriteapplicationsaccessingtheIPMCorIPMIsubsys temin
theshelf.TheCPMKCSinterfaceiscompatiblewithOpenIPMI.