On Mon, 3 May 1999, Naushit Sakarvadia wrote:
> Can anybody tell me how much Linux Kernel is dependent on BIOS ?
> Till I have figure out that for PCI card/.bus it is dependent on Bios
> what else should
> I consider if I want to remove BIOS from my Single board computer?
PCI is one of the bigger things to consider since you will have to develop
some PCI autoconfig routines to enumerate the PCI bus(es) if you dump your
BIOS firmware. If your PHB is flexible enough to have programmable
windows (don't know what is in modern x86 chipsets), there is a lot of
config to be done there as well.
Additionally, you will need routines to read the SPD on SDRAMs, and
configure the memory controller with timing/sizing information.
L1/L2 caches have to be enabled and configured.
Any CPU specific configuration has to be configured. pipelining options,
branch history prediction etc.
There are gains to be had for bypassing the firmware...notably the
flexibility of having your own slim bootloader and no bloated BIOS boot
sequence to go through. However, the overhead to get there is enormous.
Bringing modern high-end systems up from scratch can be a PITA. Also, if
you want to take your code to an updated hardware platform when a new SBC
comes out, you have to rework your entire bootloader.
> And please can anybody tell me how many SBC( single board computers )
> uses PCI interfaces?
Best I can say is "a lot". All the PowerPC systems I work with are
PCI-based...you're really looking for info on i386 SBC's so I'll leave
that to others.
--
Matt Porter
[EMAIL PROTECTED]
This is Linux Country. On a quiet night, you can hear Windows reboot.
