[Milkymist-devel] fix broken compile & minor development for milkymist bios

[sebastien.bourdeauducq at lekernel.net]

> Another patch is for character view of memory when using mr command.
> I am using it for some debug purposes. like, viewing stack area or
> a character array after a kernel crash.

Be careful with this - keep in mind that when the memory is written by the
kernel, data remains in the level 2 (L2) cache (between WISHBONE and FML)
and is not flushed immediately to the SDRAM. So you have a risk of getting
old data when you read it afterward from the BIOS.

If you run the BIOS by pressing the "CPU reset" button on the ML401, you're
OK: the cache is not cleared and you will still get the latest data written
by the Linux kernel (read from the cache).

If you reconfigure the FPGA, the L2 cache is cleared and you will read the
data from the SDRAM, which is likely to be outdated. The SDRAM is also not
refreshed while the FPGA reconfigures itself and data can be corrupted.

Sebastien