PCI and the i960RP PCI-to-PCI Bridge

Once the i960 local memory and the IMC and CIP are initialized, it is time to configure the PCI devices. Depending on the configuration of the i960RP, all the PCI devices on the ISE board can be made either private or public. A public device is one who's PCI configuration space is available to the host computer. Configuration cycles from the primary PCI bus may be forwarded to public PCI devices, but not to private devices.

The order of events for configuring PCI devices, then, is as follows:

1. Initalize hardware to function as PCI devices. This includes setting non-PCI registers and loading chip firmware.
2. Select and configure which devices are public and which are private PCI devices. Disable the BARs for all the private devices.
3. Turn on the i960 bridge unit, and allow the BIOS to configure the devices as necessary.
4. Locate and map the private devices in PCI space not allocated by the host BIOS.

The following sections will describe how to do the various steps, but first a word on PCI and configuration cycles.

• Configuration Cycles in General
• Selecting Public and Private Devices
• Enable Configuration Cycles
• Mapping the Private PCI Devices
• The DEC 21152 PCI to PCI Bridge