BCM5722 Programmer’s Guide
10/15/07
Section 6: Receive Data Flow........................................................................................... 59
Introduction.................................................................................................................................................59
Receive Producer Ring ..............................................................................................................................61
Setup of Producer Rings using RCBs ...................................................................................................61
Receive Producer Ring RCB—Register offset 0x2450–0x245f .....................................................61
Other Considerations Relating to Producer Ring Setup.........................................................61
RCB Setup Pseudo Code...............................................................................................................62
Receive Buffer Descriptors....................................................................................................................62
Management of Rx Producer Rings with Mailbox Registers and Status Block .....................................63
Status Block ...................................................................................................................................63
Mailbox...........................................................................................................................................63
Receive BD Producer Ring Producer Index...........................................................................63
Receive Return Rings.................................................................................................................................65
Management of Return Rings with Mailbox Registers and Status Block...............................................65
Host Buffer Allocation............................................................................................................................65
Receive Rules Setup and Frame Classification ....................................................................................66
Receive Rules Configuration Register ...........................................................................................66
Receive List Placement Rules Array..............................................................................................66
Class of Service Example ..............................................................................................................68
Checksum Calculation ...............................................................................................................................68
VLAN Tag Strip ...........................................................................................................................................69
RX Data Flow Diagram ...............................................................................................................................70
Receive Side Scaling (BCM5755 and BCM5755M Only)..........................................................................71
Overview................................................................................................................................................71
Functional Description...........................................................................................................................71
RSS Parameters....................................................................................................................................72
Hash Function ................................................................................................................................72
Hash Type......................................................................................................................................72
Hash Mask .....................................................................................................................................72
Indirection Table.............................................................................................................................72
Secret Hash Key ............................................................................................................................73
RSS Initialization ...................................................................................................................................73
RSS Rx Packet Flow .............................................................................................................................73
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