PCI Bridge
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
9-70 Freescale Semiconductor

Figure 9-64. I2O Message Queue

I2O defines extensions for the PCI bus hardware through which message queues are managed in hardware.

9.12.3.1 PCI Configuration Identification

A host identifies an IOP by its PCI class code. When I2O is enabled, configuration information is provided

through the PCI configuration space to the host. Refer to the following:

Section 9.11.2.6, “PCI Bus Programming Interface Register”

Section 9.11.2.7, “Subclass Code Register”

Section 9.11.2.8, “PCI Bus Base Class Code Register”

9.12.3.2 Inbound FIFOs

The inbound FIFO allows external PCI masters to post messages to the local processor. I2O defines two

inbound FIFOs—an inbound post FIFO and an inbound free FIFO.

MFA
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Inbound free list FIFO
Inbound post list FIFO
Outbound post list FIFO
Outbound free list FIFO
Head pointer
Tail pointer
Local processor write
PCI master read
PCI master write
Local processor read
Local processor read
Local processor write
PCI master write
PCI master read
Outbound
Tail pointer
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Head pointer
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Local memory
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