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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Develepor’s Manual
Order Number: 306262-004US
499
PCI Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
— Interrupt Acknowledge, Special Cycle, I/O, Configuration, and single-data-
phase Memory cycles are generated indirectly by AHB masters using a Non-
pre-fetch CSR mechanism. Refer to
“PCI Controller Configured as Host” on
for additional details.
For PCI bus memory cycles, the PCI Initiator interface will receive requests for PCI
transfer from the PCI Controller DMA channels. For PCI bus I/O cycles and configuration
cycles, the PCI Initiator interface will receive requests for PCI transfer from an AHB
master (a single word PCI Bus Memory Cycle can be produced using this method).
Requests for PCI transfers using the PCI Controller Initiator interface are buffered in
the Initiator Request FIFO and handled by the PCI Controller Initiator interface when
appropriate. The Initiator interface will receive the appropriate transfer information
from the Initiator Request FIFO; which is the address, word count, byte enables, and
PCI command type.
The Initiator Request FIFO is a four-entry FIFO allowing up to four requests to be
buffered. If a request is issued that generates an initiator transaction and the Initiator
Request FIFO is already full, a retry will be issued to the AHB master that initiated the
request.
After gathering the appropriate information, the PCI Initiator interface performs the
specified transaction on the PCI bus, handling all bus protocol and any retry/disconnect
situations. The data will be moved from the South AHB to the PCI bus using the
Initiator Data FIFOs. The Initiator Data FIFOs are eight words deep.
supported PCI transaction types produced by the PCI Controller Initiator Interface of
the IXP45X/IXP46X network processors.
It is important to note that the target interface — and the DMA channels used for
supporting the initiator interface — can contend for the use of the South AHB Master
Controller. When this contention occurs, arbitration for control of South AHB Master
Controller is carried out on two levels.
Table 190.
PCI Initiator Interface Supported Commands
PCI Byte Enables
Command Type
Support
0x0
Interrupt Acknowledge
Supported
0x1
Special Cycle
Supported
0x2
I/O Read
Supported
0x3
I/O Write
Supported
0x4
(Reserved)
0x5
(Reserved)
0x6
Memory Read
Supported
0x7
Memory Write
Supported
0x8
(Reserved)
0x9
(Reserved)
0xA
Configuration Read
Supported
0xB
Configuration Write
Supported
0xC
Memory Read Multiple
Supported
0xD
Dual Address Cycle
Not supported
0xE
Memory Read Line
Supported
0xF
Memory Write and Invalidate
Not supported