On Tue, Aug 07, 2012 at 03:42:45PM -0700, Lucas Stach wrote:
Am Dienstag, den 07.08.2012, 15:28 -0700 schrieb Allen Martin:
On Tue, Aug 07, 2012 at 10:53:00AM -0700, Lucas Stach wrote:
Hi Allen,
And to answer Tom's question: the failure was that the real U-Boot would not come up after the SPL. All I could see was the one line printed by the SPL and nothing more.
I think I found the problem. It's the following code from start.S:
ENTRY(cpu_init_crit) /* * Jump to board specific initialization... * The Mask ROM will have already initialized * basic memory. Go here to bump up clock rate and handle * wake up conditions. */ mov ip, lr @ persevere link reg across call bl lowlevel_init @ go setup pll,mux,memory mov lr, ip @ restore link mov pc, lr @ back to my caller ENDPROC(cpu_init_crit)
The "ip" register is not preserved across function calls, and the CodeSourcery compiler is using it in lowlevel_init or one of the functions it calls. This code was there before the SPL changes, but wasn't being called because CONFIG_SKIP_LOWLEVEL_INIT was set, but now it isn't.
Lucas, can you try the following change? I tested it on seaboard with CodeSourcery arm-2011.09-70-arm-none-linux-gnueabi and I'm able to boot a kernel.
Yes I can confirm this fixes the issue without further workarounds. Thanks, and:
Tested-by: Lucas Stach dev@lynxeye.de
Digging a little deeper into this, cpu_init_crit() and lowlevel_init() are called before the stack is setup, so the fact that we call into C code on tegra here is probably the bigger issue. I think the correct fix here is for me to move the code from lowlevel_init() to board_init_f().
-Allen