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SRIOFunctionalDescription
Figure17.QueueMappingRegisterRXU_MAP_Ln
3130292423222116
LetterMaskMailboxMaskLetterMailbox
R/W-11R/W-111111R/W-0R/W-000000
150
SOURCEID
R/W-0x0000
LEGEND:R=Read,W=Write,n=valueatreset
Figure18.QueueMappingRegisterRXU_MAP_Hn
3116
Reserved
R-0
151098765210
ReservedttReservedQueueIDPromisSegme
cuousnt
Mappi
ng
R-0R/W-01R-00R/W-0000R/W-0R/W-0
LEGEND:R=Read,W=Write,n=valueatreset
ThepacketmanagermaintainstheRXDMAstateoffreeanduseddatabufferswithinthememoryspace.
Itdirectsthedatatospecificaddresseswithinthememoryandmaintainsandupdatesthebuffer
descriptorqueues.ThereisasinglebufferdescriptorperRapidIOmessage.Forexample,singlesegment
messageshaveonebufferdescriptor,asdomulti-segmentmessageswithupto4KBpayloads.
TherecanbemultipleRXbufferdescriptorqueuespercore.Itissuggestedthatonequeuebededicated
tosinglesegmentmessagesandadditionalqueuesbededicatedtomulti-segmentmessages.Each
multi-segmentmessagequeuecansupportonlyoneincomingmessageatatime.Dependingonthe
application,itmaybenecessarytosupportmultiplesimultaneousSARoperationspercore.Inthiscase,a
bufferdescriptorqueueisallocatedforeachdesiredsimultaneousmessage.Theperipheralsupportsa
totalof16assignableRXqueuesandtheirassociatedRXDMAstateregisters.Eachofthequeuescan
beassignedtosingleormulti-segmentmessages.
Table15andTable16showtheRXDMAStateRegisters.
Table15.RXDMAStateHeadDescriptorPointer(HDP)(AddressOffset0x600-0x63C)
BitNameDescription
31:0RXQueueHeadRxQueueHeadDescriptorPointer:Thisfieldisthehostmemoryaddressforthefirstbuffer
DescriptorPointerdescriptorinthechannelreceivequeue.Thisfieldiswrittenbythehosttoinitiatequeuereceive
operationsandiszeroedbytheportwhenallfreebuffershavebeenused.Anerrorcondition
resultsifthehostwritesthisfieldwhenthecurrentfieldvalueisnonzero.Theaddressmustbe
32-bitwordaligned.
Table16.RXDMAStateCompletionPointer(CP)(AddressOffset0x600-0x63C)
BitNameDescription
31:0RXQueueRxQueueCompletionPointer:Thisfieldisthehostmemoryaddressforthereceivequeue
CompletionPointercompletionpointer.Thisregisteriswrittenbythehostwiththebufferdescriptoraddressforthelast
bufferprocessedbythehostduringinterruptprocessing.Theportusesthevaluewrittento
determineiftheinterruptshouldbedeasserted.
SPRU976–March2006SerialRapidIO(SRIO)43
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