Descriptor Rings
BCM5718 Programmer’s Guide
Broadcom
®
January 29, 2016 • 5718-PG108-R
Page 73
Send Rings
The controller devices covered in this document support only one host based Send Ring.
The Send Ring Producer Index is incremented by host software to add descriptors to the Send Ring (see
). By adding descriptors to the ring, the device is instructed to transmit packets that are
composed of the buffers pointed to by the descriptors. A single transmit packet may be composed of multiple
buffers that are pointed to by multiple send descriptors. The maximum number of send descriptors for a single
packet is (0.75)*(ring size).
2
Host Address High 0x2530
0x2520
0x220
Host Address Low 0x2534
0x2524
0x224
Max Length/Flag
0x2538
0x2528
0x228
NIC Address
0x253C
0x252C
0x22C
3
Host Address High 0x2550
0x2540
0x230
Host Address Low 0x2554
0x2544
0x234
Max Length/Flag
0x2558
0x2548
0x238
NIC Address
0x255C
0x254C
0x23C
4
Host Address High 0x2570
0x2560
0x240
.....
.....
.....
.....
.....
16
Host Address High 0x26F0
0x26E0
0x300
Host Address Low 0x26F4
0x26E4
0x304
Max Length/Flag
0x26F8
0x26E8
0x308
NIC Address
0x26FC
0x26EC
0x30C
Note:
[0x2450 .. 0x245C] and [0x2440 .. 0x244C] are legacy RCB addresses and are being assigned
to VRQ Ring# 0.
Note:
The Return Ring RCBs are Memory Mapped. Memory Address [0x200 .. 0x23C] are legacy
Return Ring RCB addresses and are being assigned to VRQ Return Ring# 0 through Ring# 3
Table 7: High Priority Mail Box Registers for VRQ Rings (Cont.)
VRQ #
Register Name
Standard Ring RCB
Register Address
Jumbo Ring RCB
Register Address
Return Ring RCB Register
Address (**)