Intel IXP42X 用户手册
Intel
®
IXP42X product line and IXC1100 control plane processors—AHB Queue Manager (AQM)
Intel
®
IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
DM
September 2006
568
Order Number: 252480-006US
§ §
Register Name:
QUECONFIG (0 <= n <=63)
Physical Address:
Queue #n 0x(2000 + 4n)
Reset Hex Value:
0xUUUUUUUU
Register Description:
Queue #n configuration word located in SRAM.
Access:
31
24 23
16 15
8
7
0
Queue (n)
NF
Watermark
Queue (n)
NE
Watermark
Q (n)
Buffer
Size
Q (n)
Entry
Size
Queue (n) Base
Address
Res.
Queue (n) Read Pointer
Queue (n) Write Pointer
Register
QUECONFIG (0 <= n <=63)
Bits
Name
Description
Reset
Value
Access
31:2
9
Nearly Full
Watermark
The Nearly Full Watermark can be configured via these bits. The
Nearly Full Watermark can be set in the range 0 (“000”), 1 (“001”), 2
(“010”), 04(“011”), 8 (“100”), 16 (“101”), 32 (“110”), or 64 (“111”)
entries from the top of the queue. The usable range for the Nearly Full
Watermark selection is limited to a value less than the buffer size.
U
R/W
28:2
6
Nearly Empty
Watermark
The Nearly Empty Watermark can be configured via these bits. The
Nearly Empty Watermark can be set in the range 0 (“000”), 1 (“001”),
2 (“010”), 04(“011”), 8 (“100”), 16 (“101”), 32 (“110”), or 64 (“111”)
entries from the bottom of the queue. The usable range for the Nearly
Empty Watermark selection is limited to a value less than the buffer
size.
U
R/W
25:2
4
Buffer Size
These bits are used to configure the queue buffer size. The buffer size
can be configured for 16 (“00”), 32 (“01”), 64 (“10”) or 128 (“11”)
words
U
R/W
23:2
2
Entry Size
These bits are used to configure the queue entry size of the queue.
The entry size can be set at 1 (“00”) or 2 (“01”) or 4 (“10”) words. An
input of “11” results in the entry size being set at 1.
U
R/W
21:1
4
Base Address
This field is used to configure the starting base address of the queue.
The read and write pointer are offset addresses from the base
address. This base address is a SRAM 16 word address. Base
addresses, 00 to 03, are reserved for the Queue Configuration Words.
The most significant bit of the base address will be reserved for growth
to a 16 KB SRAM, thus providing 8 KB of additional queue buffer
space.
U
R/W
13:7
Read Pointer
This is a pointer to the next entry to be read from the queue. The
pointer is the AQM’s internal SRAM word address. In general, this
pointer should initialized to zero, and not be written except for
diagnostic or test purposes.
U
R/W
6:0
Write Pointer
This is a pointer to the next entry to be written to the queue. The
pointer is the AQM’s internal SRAM word address. In general, this
pointer should initialized to zero, and not be written except for
diagnostic or test purposes.
U
R/W