[coreboot] GeodeLX RAM initialisation issue

[Nathan Williams]

Marc Jones wrote:
> When linux does the reset, is the coreboot output the same? Does it do
> the "Resetting the processor"?

Yes, it does "Resetting the processor after PLL configuration for the 
changes to take effect"

I captured an example of my issue:

http://coreboot.pastebin.com/m7f5ed367

I made some more observations today:

 From Linux, a reboot from the command line works fine.  It only seems 
to  die when a fsck check fails on boot and forces a reboot.  The 
motherboard doesn't have a RTC backup battery at the moment, so to test 
I have been setting the clock in Linux, shutdown, remove the power 
supply for a few seconds, then boot up again.  Because the default time 
is in 1999, Linux runs a fsck which causes it to restart and die in 
coreboot.

Once coreboot crashes, a hardware reset doesn't fix it.  Coreboot will 
always stop at the same point.  Even removing power from the motherboard 
doesn't help.  However, I did find that by swapping the SODIMM to a 
different RAM module would boot.  I know it doesn't sound very 
scientific but it's what appeared to happen.

Is it possible that coreboot or maybe SeaBIOS is using incorrect values 
from non-volatile ram?

Another observation I made was that by setting the debug_level to 
BIOS_CRIT, instead of dying at the usual spot in disable_car() and 
stopping, coreboot would reset continuously (cycling every 1-2 seconds)

Another issue that's partly related is the ability for coreboot to set 
  the GeodeLink speed depending on the detected RAM speed.  As a 
work-around, we are only using 333MHz SODIMMs and have set the bootstrap 
bits for GLCP_SYS_RSTPLL[7:1] (section 6.14.2.13 of LX databook) to 
500Mhz CPU, 333MHz GLIU instead of bypass mode.  In bypass mode, the 
GLIU is 266MHz and some of our 333MHz RAM will fail in disable_car(). 
As a test, I have experimented with
pll_reset(MANUALCONF, PLLMSRHI, PLLMSRLO) in initram.c in an attempt to 
change the GLIU to 333MHz.  I probably didn't have the correct bits set, 
so even though I managed to set GLIU, it failed the last test (DLL) in 
sdram_enable() and would reset.

Nathan