fixes/contribs to libbsp/powerpc/shared

[strauman]

The "libbsp/powerpc/shared" BSP has been modified considerably
with the goal to make it more flexible and reusable by other
BSPs. The main strategies were:

• eliminate hardcoded base addresses; devices use offsets and a BSP defined base address.
• separate functionality into different files (e.g. reboot from inch.c to reboot.c) which can be overridden by a 'derived' BSP.
• separate initialization code into separate files (e.g. PCI bridge detection/initialization was separated from the more generic PCI access routines), also to make it easier for 'derived' BSPs to substitute their own initialization code.

There are also a couple of enhancements and fixes:

• IRQ handling code now has a hook for attaching a VME bridge.
• OpenPIC is now explicitely initialized (polarities, senses). Eliminated the implicit assumption on the presence of an ISA PIC.
• UART and console driver now supports more than 1 port. The current maximum of 2 can easily be extended by enlarging a table (it would even be easier if the ISR API was not broken by design).
• fixed polled_io.c so it correctly supports console on COM2
• fixed TLB invalidation code (start.S).
• exception handler prints a stack backtrace.
• added BSP_pciFindDevice() to scan the pci bus for a particular vendor/device/instance a la vxWorks.

NOTE: THIS PATCH REQUIRES A RELATED PATCH SUBMITTED IN PR#215

Release:
RTEMS-ss-20020301

Environment:
Target: powerpc-rtems

How-To-Repeat:
n.a.

[Joel Sherrill]

State-Changed-From-To: open->closed
State-Changed-Why: Patch applied. I have built nothing! I had trouble

generating the new files so be warned. They ended up
in /tmp/cvsxxx and I had to deal with them by hand. I think
I have handled it though.

Thanks.

[strauman]

libbsp_powerpc_shared.diff