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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Reference Number: 306262-004US
275
UTOPIA Level 2—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
The counters are not cleared when read by the Network Processor Engine core. The
Network Processor Engine core must perform an explicit write to the specified register
to clear the counter values.
There is an overflow bit per counter to indicate that the count has “rolled over.” A mask-
able interrupt mechanism is used to allow the UTOPIA Level 2 Coprocessor to flag to
the Network Processor Engine Core that a “roll over” has occurred.
7.4
UTOPIA Level 2 Coprocessor / NPE Coprocessor: Bus
Interface
The Network Processor Engine Coprocessor Interface Module provides the necessary
interface logic required for configuration, monitoring, control, and test of the UTOPIA 2
coprocessor. All of the UTOPIA 2 coprocessor’s internal configuration and control
registers, instruction registers, and FIFOs are directly accessible by the Network
Processor Engine core.
7.5
MPHY Polling Routines
The UTOPIA 2 coprocessor implements a round-robin polling algorithm. The Receive
and Transmit modules use a logical-to-physical address-translation table to determine
the actual physical interface that is to be polled. This feature allows the designer
complete control over the physical address polling sequence.
The multiple-PHY (MPHY) address translation is used by the UTOPIA Level 2 Interface,
on the IXP45X/IXP46X network processors, to poll physical addresses that are not
contiguous or do not start at 0.
There are two translation tables implemented. One translation table is used for receive
interface polling and the other translation table is used for transmit interface polling.
Each translation table is implemented as 31 5-bit registers. Each register is addressed
from 0 to 30, corresponding to one of 31 logical addresses.
The five bits of each register are used to designate a physical interface number.
Therefore if a binary value of 00101 is written to address location 0 (logical port 0) of
the transmit translation table, the polling sequence would actually assert a five on the
transmit (UTP_OP_ADDR) address lines of the UTOPIA Level 2 interface during logical
port 0’s turn in the polling algorithm.
For example, make the following assumptions:
• A design requires eight physical interfaces to be connected, which are configured to
respond to addresses 0 through 7.
• The polling order of the physical interfaces is required to be 1, 3, 5, 7, 0, 2, 4, and
6 for both transmit and receive.
To accomplish this polling sequence:
1. The Network Processor Engine core will set the TXADDRRANGE and the
RXADDRRANGE to a hexadecimal value of 0x7.
This will identify that there are eight physical interfaces attached and involved in
the polling sequence.
2. Define the values in both the transmit and receive translation tables as follows:
— Address 0 (logical address 0) = A binary value of 00001
— Address 1 (logical address 1) = A binary value of 00011
— Address 2 (logical address 2) = Aa binary value of 00101
— Address 3 (logical address 3) = Aa binary value of 00111