Intel NETWORK PROCESSOR IXP2800 - Manual (Page 267)

Hardware Reference Manual 267
Intel
®
IXP2800 Network Processor
Media and Switch Fabric Interface
8.3.2.2 CSIX
For CSIX protocol, the TBUF should be set to two partitions in
MSF_Tx_Control[TBUF_Partition], one for Data traffic and one for Control traffic.
Payload information is put into the Payload area of the element, and Base and Extension Header
information is put into the Element Control Word.
Data is stored in big-endian order. The most significant byte of each 32-bit word is transmitted
first.
When the Element Control Word is written the information is (note that the data comes from two
consecutive Transfer registers; bits [31:0] from the lower numbered and bits[63:32] from the
higher numbered):
The definitions of the fields are shown in Table 99 .
3
1 3
0 2
9 2
8 2
7 2
6 2
5 2
4 2
3 2
2 2
1 2
0 1
9 1
8 1
7 1
6 1
5 1
4 1
3 1
2 1
1 1
0
9 8 7 6 5 4 3 2 1 0
Payload Length
Prepend
Offset
Prepend Length
Payload
Offset
Res Ski
p Res CR
P
Res Type
6
3 6
2 6
1 6
0 5
9 5
8 5
7 5
6 5
5 5
4 5
3 5
2 5
1 5
0 4
9 4
8 4
7 4
6 4
5 4
4 4
3 4
2 4
1 4
0 3
9 3
8 3
7 3
6 3
5 3
4 3
3 3
2
Extension Header
Table 99. TBUF CSIX Control Definition
Field Definition
Payload Length
Indicates the number of Payload bytes, from 1 to 256, in the element. The value of 0x00
means 256 bytes. The sum of Prepend Length and Payload Length will be sent, and also
put into the CSIX Base Header Payload Length field. Note that this length does not
include any padding that may be required. Padding is inserted by transmit hardware as
needed.
Prepend Offset Indicates the first valid byte of Prepend, from 0 to 7, as defined in Section 8.3.2 .
Prepend Length Indicates the number of bytes in Prepend, from 0 to 31.
Payload Offset Indicates the first valid byte of Payload, from 0 to 7, as defined in Section 8.3.2 .
Skip
Allows software to allocate a TBUF element and then not transmit any data from it.
0—transmit data according to other fields of Control Word
1—free the element without transmitting any data.
CR CR (CSIX Reserved) bit to put into the CSIX Base Header.
P P (Private) bit to put into the CSIX Base Header.
Type Type Field to put into the CSIX Base Header. Idle type is not legal here.
Extension Header
The Extension Header to be sent with the CFrame. The bytes are sent in big-endian
order; byte 0 is in bits 63:56, byte 1 is in bits 55:48, byte 2 is in bits 47:40, and byte 3 is in
bits 39:32.