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Intel
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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
558 Order Number: 252480-006US
returned via the AHB and for a queue write request, the data from the AHB is written
into the queue. Following a queue access, the read or write pointer is incremented and
the status for the accessed queue is updated as needed
21.4 AHB Interface
The AHB interface provides read/write access to all AQM configuration/status registers,
queues and SRAM. The AQM is a slave with a 32 bit data bus configuration on the AHB.
The address map for the AQM is shown in Table 176. Support is provided for the AHB
slave requirements outlined in the AMBA specification, Rev. 2.0. Unsupported
exceptions to the AHB slave requirements include accesses with a data transfer size of
byte or half-word, wrapping burst accesses and 16 beat incrementing burst accesses.
These accesses will result in an Error response. In addition, early burst termination
support, master busy support, Retry responses and Split responses will not be
implemented in the AQM. Accesses to any unused locations within the AQM address
space will result in an OKAY response on the AHB. Read accesses to the unused address
locations will result in zeroes returned on the AHB. The AQM will not perform any
internal operations on write accesses to any unused locations. Wait state performance
for the AHB interface is given in Section 21.4. Data formats for all registers accessible
via the AHB is given in Section 21.5.
Table 176. AHB Queue Manager Memory Map
Address AQM Function
0x03FFF
64 Queue Buffer Space - SRAM
1984 x 4 Bytes
0x02100
0x020FF
64 Queue Configuration Words - SRAM
64 x 4 Bytes
0x02000
0x01FFF
Reserved
0x00440
0x0043F
Queue 0 to 63 Interrupt Register
2 x 4 Bytes
0x00438
0x00437
Queue 0 to 63 Interrupt Enable Register
2 x 4 Bytes
0x00430
0x0042F
Queue 0 to 31Interrupt Status Flag Source Select Register
4x 4 Bytes
0x00420
0x0041C
Queue 32 to 63 Full Status Register
0x00418
Queue 32 to 63 Nearly Empty Status Register