The startup code in arm/cpu/arm926ejs preserves the link register across
the call to lowlevel_init by using r4:
mov r4, lr /* perserve link reg across call */
bl lowlevel_init /* go setup pll,mux,memory */
mov lr, r4 /* restore link */
The lowlevel_init function for at91 machines based on the same CPU uses r4
and hence corrupts it causing a data abort when it returns to the startup
code. This patch fixes this by using r6 instead of r4 in the lowlevel_init
function.
Discovered and the fix was tested on a AT91SAM9261 based board.
Signed-off-by: Martin Townsend <martin@rufilla.com>
Reviewed-by: Eugen Hristev <eugen.hristev@microchip.com>
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