[U-Boot-Users] Re: [uClinux-dev] [Announcement] U-Boot for Motorola M5272C3 and M5282EVB

[Bernhard Kuhn]

Wolfgang Denk wrote:

>>We could apply the same method for Coldfire as well, means the
>>pre-bootloader needs to be downloaded and compiled seperatly. This would
> 
> As discussed before, such a design  is  really  breaking  very  basic
> design  principles  of  U-Boot.

True, U-Boot is then not the "real" bootloader but just an "application"
that is decompressed from flash to ram through the pre-bootloader,
keeping pre-bootloader + variables + compressed u-boot typically below
64 KiB of flash. In low memory environments, such as the the M5272C3
EVB or the AT75C221-DK with only 2 MiB of flash, it makes a
difference if the bootloader takes 128 KiB or only 64 KiB, but YMMV :-)



>>also sort out the potential licensing issue for the 5282 decribed
>>above, as well, since the pre-bootloader is actually not linked with
>>u-boot: the pre-bootloader and the compressed u-boot are just
>>concaternated into the same file (and could be flashed seperatly).
> 
> 
> Will anybody implement such a cleanup? Bernhard? Richard?

That's actually ease: the pre-bootloaders are placed in the
"pre" directory and compiled seperatly from u-boot. Means:
after deleting the "pre" directory, u-boot will still build
for coldfire and is independendly flashable from the
pre-bootloader. Without the "pre" directory, the rest of the
coldfire patch looks pretty much the same way it was done for
other architectures - in fact i started with some ppc directories
and renamed/modified the files until it worked out. The resulting
u-boot images btw. will work "stand alone" (without pre-bootloader)
when being downloaded to ram through a JTAG debugger such as the
BDI 2000.

best regards

Bernhard