Broadcom BCM5722 Programmer's Manual page 185

Programmer's Guide
10/15/07
The interrupt mailboxes are accessible from BAR + offsets 0x00100000 to 0x0010C007. Host software may use this memory
map to access the interrupt mailboxes located in BCM5722 Ethernet controller's register block (0x200–0x21F). The Receive
Producer consumer index mailboxes are available at offsets 0x00130000–0x0013C0007. Receive return ring mailboxes are
shadowed at BAR + offsets 0x00140000 to 0x0017C007. The BCM5722 Ethernet controller receive return rings are located
in register block range 0x280–0x2FF. Host-based send rings are located at BAR + offsets 0x001800000–0x001BC007.
These send ring mailboxes are mapped from the BCM5722 Ethernet controller register block range 0x300–0x37F.
The address ranges 0x01000000–0x01FFFFFF are aliases for the BCM5722 Ethernet controller device local memory. When
host software reads/writes from address ranges starting at BAR + 0x01000000, the address is normalized/mapped to a
device local address starting at 0x00000000. For example, the host address 0x010000FF is translated to device local
address 0x000000FF.
Figure 49 on page 128 shows the two mechanisms host software may use to access BCM5722 Ethernet controller local
memory (flat mode configuration).
• First, host software can use the memory window.
• Second, host software may access the memory-mapped range 0x01000000 to 0x01FFFFFF.
The second technique is preferable since flat mode has made 32 MB of host memory-mapped space available. Software
does not need to use the memory window since the BCM5722 Ethernet controller's entire memory region is memory-
mapped.
Document 5722-PG101-R
Bro adco m Co rp or atio n
BCM5722
Configuration Space Page 126