Address Translation; Inbound Pci Address Translation - Motorola MPC8240 User Manual

Address Translation

3.3 Address Translation
The MPC8240 allows remapping of PCI to local memory (inbound) transactions and
processor core to PCI (outbound) transactions. Note that address translation is supported
only for agent mode; it is not supported when the MPC8240 is operating in host mode. Also
note that since agent mode is supported only for address map B, address translation is
supported only for address map B. The following sections describe the address translation
support of the MPC8240. Note that the address translation mechanisms are disabled upon
reset.
All the configuration registers of the MPC8240 are intrinsically little-endian. In the register
descriptions of this chapter, bit 0 is the least significant bit of the register. This bit
numbering is based upon the PCI standard for register bit order numbering and is opposite
from the standard PowerPC bit ordering where bit b0 is the most significant bit of the
register.

3.3.1 Inbound PCI Address Translation

For inbound address translation, an inbound memory window is specified in PCI memory
space and an inbound translation window is specified in the MPC8240's local memory
space. PCI memory accesses in the inbound memory window are claimed by the MPC8240
and are forwarded to local memory with the address translated to the inbound translation
window. PCI memory transactions outside of the inbound memory window are ignored (not
claimed) by the MPC8240 unless they fall within the embedded utilities memory block
(EUMB). PCI memory accesses that fall within the EUMB are handled as described in
Section 3.4, "Embedded Utilities Memory Block (EUMB)," regardless of address
translation.
Figure 3-6 shows inbound PCI address translation from PCI memory space to the local
memory space.
Chapter 3. Address Maps 3-11