[U-Boot-Users] [ANNOUNCE] u-boot-ptx-20030213-1
chaos at in.fer.no
Thu Feb 13 21:42:51 CET 2003
Robert Schwebel wrote:
> Comments are welcome...
in cpu/xscale/start.S you do:
/* test if we run from flash or RAM - RAM/BDI: don't set cpuspeed */
/* FIXME: is the criterium used here only valid for PXA25X? */
mov r0, pc
and r0, r0, #0xF0000000 /* RAM is at 0xa0000000-0xafffffff */
subs r0, r0, #0xa0000000
mov r0, #2
mcr p14, 0, r0, c6, c0, 0
Why? I can trace trough the CPU speed setting code without any trouble
with a BDI, and I don't understand why there should be any problems
doing so. Disabeling the CPU speed setting code without skipping the
SDRAM init code at the same time might actually get you into other
problems since the refresh periode of the SDRAM might be too long.
Jumping over the SDRAM init is a very good idea, since the code is
running from the SDRAM that the code is initializing. One important step
of the init sequence is to disable the SDRAM.
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