Geode Kernel Config

Christer Weinigel christer at
Wed Nov 27 04:52:01 CET 2002

"Adam Bezanson" <bezanson at> writes:

> I've got an Eval card from National Semi that contains
> the SC1200. I'd like to try LinuxBios on it.
> I've downloaded both the 2.4.18 and 2.4.19 kernels to start with.
> What patches do I need to apply to the kernel?
> Is there a config file I can use to configure the kernel, or
> should I do it manually?

A normal 2.4 Linux kernel will work fine as long as you compile for a
586 CPU (CONFIG_M586), not Pentium or higher (CONFIG_M586TSC and up)
since the TSC behaves a bit differently.

If you want support for the watchdog or the GPIO pins in a 2.4 kernel,
you can find an old patch from me at:

An updated version of this patch has been included in Linux 2.5.  Alan
Cox' 2.5 kernel also has support for doing DMA on the SC1200 IDE
controller; I don't know if there is a corresponding patch for 2.4.

Other than that, take a look at the freebios/src/mainboard/nano/nano
directory and make a copy of it.  All you should have to do is to
modify the Pin Multiplexing Register (PMR) and Miscellaneous Config
Register (MCR) in the Config file and to modify the irq assignments.

Depending on what you want to do, there are a few limitations with
the current LinuxBIOS on the SC1200: 

    There is no video support in LinuxBIOS itself, so you won't get
    any video until you have loaded the NatSemi Geode Linux
    framebuffer driver (can be found at under the
    heading SP1SC10 Platform Image).

    There is no SMM/VSA support at all, this means that anything
    relying on it won't work.  What this means is that Audio won't

Other than that everything works fine, IDE in PIO mode, the PCI bus,
watchdog, GPIOs, everything.


"Just how much can I get away with and still go to heaven?"

Freelance consultant specializing in device driver programming for Linux 
Christer Weinigel <christer at>

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