Documentation for arch/ppc/kernel/*_common.c
	============================================

Author: Mark A. Greer (mgreer@mvista.com)
Date:   3.5.2001

Last Change: 3.5.2001

To make board ports easier and less error prone, some common host bridge files
have been developed.  So far, these files have been developed:
	- pplus_common.c
	- mpc10x_common.c

pplus_common.c
--------------

The routines in this file are for the Motorola MCG PowerPlus architecture
boards which have a Falcon/Raven or Hawk memory controller/host bridge.

- 'pplus_init()' completely reconfigures the PCI and MPIC physical mappings
  and maps the MPIC registers into virtual memory.
- 'pplus_mpic_init()' simply maps the MPIC registers into virtual memory from
  where they are currently mapped in the physical address space.
- 'pplus_get_mem_size()' reads the memory controller's registers to determine
  the amount of main memory in the system.  This assumes that the firmware has
  correctly initialized the memory controller.

For examples, look at arch/ppc/kernel/mcpn765_*.c and prpmc750_setup.c.


mpc10x_common.c
--------------

The routines in this file are board using the Motorola SPS MPC106/107/8240
host bridges (the MPC8240 is a 603e processor core with a MPC170-like host
bridge).

- 'mpc10x_bridge_init()' allows you to switch memory maps (e.g, switch from MAP
  A to MAP B), automatically initializes many variables with the proper values,
  moves the EUMB to a reasonable place in physical memory (assuming that
  'ioremap_base' is correct), and maps the EPIC registers into virtual memory.
- 'mpc10x_get_mem_size(()' reads the memory controller's registers to determine
  the amount of main memory in the system.  This assumes that the firmware has
  correctly initialized the memory controller.

For examples, look at arch/ppc/kernel/sandpoint_*.c and menf1_*.c.


Before calling any of the routines listed above, you must ensure that there is
a 1-to-1 BAT mapping for the areas of physical memory that will be accessed.

If you encounter problems, please email me at mgreer@mvista.com