[U-Boot] [PATCH] powerpc: add support for the Freescale P1022DS reference board

Timur Tabi
2010-05-27T20:03:43Z

Wolfgang Denk wrote:

>> It also doesn't handle non-power-of-two sized memory -- don't rely on the
>> value it returns.
>
> Such configurations are usually set up of from several differently
> sized banks of memory, and get_ram_size() is always run per bank. So
> as long as chip manufacturers continue to make RAM chips with
> power-of-two sizes only, everything should be fine.

What if the board has two DIMM slots, one of which has a 1GB DIMM and the
other has a 512MB DIMM?

>> [1] It's worse than machine checks, what if some I/O device is mapped
>> directly after RAM? IIRC people have run into this sort of problem doing
>> this type of memory sizing on PCs.
>
> Well, let's call this a bug in setting up the memory map for the
> system ;-)

I thought get_ram_size() was supposed to safely determine how much RAM is
actually in the system? Otherwise, it should be called verify_ram_size().

--
Timur Tabi
Linux kernel developer at Freescale