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Low Priority Mailboxes
BCM5718 Programmer’s Guide
Broadcom
®
January 29, 2016 • 5718-PG108-R
Page 461
General Mailbox Registers 1-8 (offset: 0x5820–0x5824)
This mailbox serves two functions. When the host writes it, the interrupt (IntA) is cleared. It is also used by the
Host Coalescing engine to determine if the host is in the interrupt handler. If it is non-zero this indicates the host
is in the interrupt handler. If it is zero this indicates the host is not in the interrupt handler. The Host Coalescing
engine uses this information to determine which set of coalescing parameters it should use.
Receive BD Standard Producer Ring Index Register (offset: 0x5868)
The Receive BD Standard Producer Ring Index register, contain the index of the next buffer descriptor for the
standard producer ring that will be produced in the host for the NIC to DMA into NIC memory. Host software
writes this register whenever it updates the standard producer ring. This register must be initialized to 0.
Receive BD Jumbo Producer Ring Index Register (offset: 0x5870-
5877)
The Receive BD Extended Producer Ring Index Register contains the index of the next buffer descriptor for the
extended producer ring that will be produced in the host for the NIC to DMA into NIC memory. Host software
writes this register whenever it updates the extended producer ring. This register must be initialized to 0.
Receive BD Return Ring 0 Consumer Index Register
(offset: 0x5880-0x5887)
The Receive BD Return Ring 0 Consumer Index Register contains the index of the last buffer descriptor for
Receive Return Ring 0 that has been consumed. Host software writes this register whenever it updates the
return ring 0. This register must be initialized to 0.
Receive BD Return Ring 1 Consumer Index Register
(offset: 0x5888-0x588F)
The Receive BD Return Ring 1 Consumer Index Register contains the index of the last buffer descriptor for
Receive Return Ring 1 that has been consumed. Host software writes this register whenever it updates the
return ring 1. This register must be initialized to 0.
Name
Bits
Access
Default
Value
Description
Received BD jumbo
Producer Ring Index
7:0
RW
–
The Receive BD Extended Producer Ring Index
register contains the index of the next buffer
descriptor for the extended producer ring that will
be produced in the host for the controller to DMA
into controller memory. Host software writes this
register whenever it updates the extended
producer ring. This register must be initialized to 0.