User manual

252 Hardware Reference Manual
Intel
®
IXP2800 Network Processor
Media and Switch Fabric Interface
The status contains the following information:
The definitions of the fields are shown in Table 90.
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
9876543210
RPROT
Element Byte Count
SOP EOP
Err
Len Err
Par Err
Abort Err
Null
Type
ADR
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
Reserved Checksum
Table 90. RBUF SPIF-4 Status Definition
Field Definition
RPROT
This bit is a 0, indicating that the Status is for SPI-4. It is derived from the RPROT input
signal.
Element
The element number in the RBUF that holds the data. This is equal to the offset in RBUF
of the first byte in the element, shifted right by six places
Byte_Count
Indicates the number of Data bytes, from 1 to 256, in the element (value 0x00 means
256). This field is derived from the number of data transfers that fill the element, and also
the EOPS field of the Control Word that most recently succeeded the data transfer.
SOP
Indicates whether the element is the start of a packet. This field is taken from the SOP
field of the Control Word that most recently preceded the data transfer for the first element
allocated after a Control Word. For subsequent elements (i.e., if more than one element
worth of data follow the Control Word) this value is 0.
EOP
Indicates whether the element is the end of a packet. This field is taken from the EOPS
field of the Control Word that most recently succeeded the data transfer.
Err Error. This is the logical OR of Par Err, Len Err, and Abort Err.
Len Err A non-EOP burst occurred that was not a multiple of 16 bytes.
Par Err Parity Error was detected in the DIP-4 parity field. See the description in Section 8.2.8.1.
Abort Err
An EOP with Abort was received on bits [14:13] of the Control Word that most recently
succeeded the data transfer.
Null
Null receive. If this bit is set, it means that the Rx_Thread_Freelist timeout expired
before any more data was received, and that a null Receive Status Word is being pushed,
to keep the receive pipeline flowing. The rest of the fields in the Receive Status Word
must be ignored; there is no data or RBUF entry associated with a null Receive Status
Word.
Type
This field is taken from the Type field of the Control Word that most recently preceded the
data transfer.
ADR
The port number to which the data is directed. This field is taken from the ADR field of the
Control Word that most recently preceded the data transfer.
Checksum Checksum calculated over the Data Words in the element. This can be used for TCP.