powerpc/motorola_powerpc: Add MVME2700 BSP

[Chris Johns]

On 7/4/2023 1:28 am, Joel Sherrill wrote:
> Random (and late) question. For this generic BSP, the bsp.h has this:
> 
> LIBBSP_POWERPC_MOTOROLA_POWERPC_BSP_H
> 
> as the bsp guard. libbsd uses that to configure the nexus device and 
> peripherals. Are there board model differences which need to be taken
> into account? We would need a secondary define. The QorIQ has
> examples of that I think.

There is more work needed in libbsd for the BSP variants. At the moment on the
6-freebsd-12 branch it is only the DEC tulip driver and the unknown PHY. We can
use the RTEMS_BSP define to implement the specific changes when the time comes.
I am not sure when that will be. This patch is about the legacy stack and
compatibility and not libbsd.

The tulip driver in libbsd is for version 3 (I think) and later silicon and the
MVME2700 has rev 1 so I am not comfortable using it in production until it has a
number of hours in testing. As a result I am making sure the legacy stack is
fully functional with RTEMS 6 and it is. Nice work Vijay. This however effects
the RTEMS and EPICS integration.

Chris