LinuxBios support for the ELAN SC520

Robin Randhawa robin.randhawa at
Tue Feb 22 05:14:00 CET 2005

Greetings List and Hi Ron!

Ron, its been a while since I made on offlist enquiry about Linuxbios
support for AMD's ELANSC520 microcontroller. Couldn't get my hands on
the devel board hence the delay. Apologies for the same! I'll have the
board by the weekend so I thought now would be a good time to get my
perspective right.

Here's the spill:

I've been asked to get Linux 2.6.x up on a BIOS-less custom devel board
built around this controller and would love to collaborate and get some
help from this community. I would love to put up my experience if it
would help others.

But first, some pre-requisites. I have some degree of expertise with
deeply embedded RTOS' such as eCos (did a port to a multicore board) and
bootloaders such as RedBoot but have never ventured strictly into the
Linux BSP domain, though I call myself a Linux power user (not in any
way grandiose!) and have done a fair amount of Linux Device Driver work.

After a bit of digging around, I've narrowed down my choice of
bootloaders to telios' ALIOS and Linuxbios from you good people. Alios
seems to support only the ELAN SC400 and I am not sure of the existing
Linuxbios support for the ELAN SC520.

Could someone please inform me if this microcontroller is currently
supported ?

My strategy, based on AMD's recommendations for the SC520 is to come up
with bootstrap code which does the following (from scratch if I have no
other option, but I'm hoping that Linuxbios will come to the rescue!) :

1. From the reset vector (which just 16Kb from the top of physical mem),
jump to a more spacious area
2. Switch to protected mode
3. Bring up the DRAM
4. Copy a Linux elf image which is at some safe location in ROM to the
5. Jump to it

Now while that may sound fine and dandy, I am plagued by very basic and
fundamental questions which I will pop up as things move along.

Since this micro is core compatible with a pentium, I intend using
standard pentium GNU tools.

For the moment, I would really appreciate pointers to experiences,
documentation, tutorials et al. I could supply more info as needed.

Thanks a tonne and keep up the good work!


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