Intel® IXP42X product line and IXC1100 control plane processors—PCI Controller
Intel® IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
DM September 2006
208 Order Number: 252480-006US
6.0 PCI Controller
The Intel® IXP42X Product Line of Network Processors and IXC1100 Control Plane
Processor contains a 32-bit, 66-MHz PCI interface compatible with PCI Version 2.2. The
PCI interface is capable of operating as either a host or an option (i.e., not the host).
The PCI Controller supports these modes of operation by enabling access to the Intel®
IXP42X product line and IXC1100 control plane processors’ configuration register space
from either the Intel XScale® Processor when operating as a host or from an external
PCI Device using the PCI Bus when configured as an option. Initiator or target
operations are supported by the PCI interface irrelevant of the IXP42X product line and
IXC1100 control plane processors’ configurations (could be configured as a PCI Host or
PCI Option Function).
When the PCI Controller is configured as a host, an internal PCI arbiter may be utilized
to allow up to four devices to be connected to the IXP42X product line and IXC1100
control plane processors without the need for an external arbiter. However, even
though the internal PCI arbiter exists, the internal PCI arbiter is not required to be used
when the PCI Controller is configured in host or for that matter option mode of
operation.The arbiter functionality is completely independent from the PCI mode of
operation. An example connection of this configuration is contained in Figure 30. The
PCI arbiter function will allow access to the PCI bus in a round-robin fashion. The PCI
Controller operating as an initiator can generate Memory, I/O, or Configuration PCI bus
cycles.
Operating as a target, the PCI Controller can accept Memory, I/O, or Configuration PCI
bus cycles. When the PCI Controller is configured as an option, the internal PCI arbiter
can be disabled and REQ0/GNT0 are used to connect to an external arbiter on the PCI
bus.
An example of the IXP42X product line and IXC1100 control plane processors
connected in this configuration is shown in Figure 31. The PCI arbiter can be enabled/
disabled independently from the PCI host/option configuration. The PCI Controller also
contains two DMA engines to allow data movement between the PCI bus and the
SDRAM without the aid of the Intel XScale processor.