As promised, a watchdog driver for the Geode GX/LX processors is attached.
I basically just ported the previous patch forward to 2.6.24.
I also have good news or bad news depending on your perspective. I wanted
to test this against 2.6.24, and OLPC is stuck at an older kernel version,
so I had to test this with coreboot (LinuxBIOS) on another Geode
platform. Like all BIOSen execpt for the OLPC firmware, coreboot uses
VSA (SMM handler) which consumes all the timers.
So I used the magical MSR and surprise! - the timer tick hung.
I compiled out the timer tick, and tested the watchdog timer instead,
and it worked fine on timer 0. So I don't think the MFGPTs themselves
have anything to do with this problem, but I do think it might be
related to VSA and possibly interrupts too. I'm going to invoke the
strong BIOS fu of our LinuxBIOS / BIOS expert Marc Jones, and see what
he comes up with.
I don't know how much of a hassle it would be for Andres to get a 2.6.24
kernel running on the OLPC to make sure that this isn't a regression
in the timer tick code (I suspect it isn't a regression, but you never
know). I also think that it would probably be in our best interest to
default CONFIG_GEODE_MFGPT_TIMER to 'n' until we get this figured
out. Since most BIOSen don't have timers available, that shouldn't affect
too many people.
So, anyway, enjoy the watchdog timer - I hope it meets everybody's
expectations for the 2.6.25 kernel.
Jordan
--
Jordan Crouse
Systems Software Development Engineer
Advanced Micro Devices, Inc.
