Emulation/switch-coreboot
1
0
Fork 0
mirror of https://github.com/fail0verflow/switch-coreboot.git synced 2025-05-04 01:39:18 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Update the README so it agrees with reality.

Browse source
This commit is contained in:
Ronald G. Minnich 2001-08-31 22:25:35 +00:00
parent ce4630e8d0
commit 24e46ba9f3
1 changed files with 5 additions and 72 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

77
README
View file

@ -1,81 +1,14 @@
This is FreeBIOS.
This is FreeBIOS. At this point it's really linuxbios, FreeBIOS is mostly gone.
Requires bcc to compile 16-bit C code. Obtain bcc from
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/distfiles/bcc.tar.gz
To see how to build a target, you should look into the HOWTO directory.
Rough directory layout:
chip is for chipset types. chip/intel is intel mainboards. chip/stpc is
stpc systems. These are common files to both freebios and linuxbios.
lib is architecture-indepedent (we hope) code that is used by both linuxbios
and freebios.
include is what you think.
----------------------------------------------------
LinuxBIOS
-----------------------------------------------------
linuxbios is the linuxbios directory. Things for linuxbios ONLY live here.
There is an inflate directory for the inflate code, a lib directory for
common library code, an include directory, a kernel_patches directory for
patches to the various kernels, and finally, Makefile.common, an included
Makefile used by all the builds.
Actual targets are done in caps (this is a Berkeley style thing).
In each target are:
1) crt0.S for that target. These vary a bit by target, although they
do include lots of common code.
2) Makefile. This mainly has -D stuff and it includes ../Makefile.common
3) ldscript.ld. We'd like to make this common, but they seem to vary a lot
4) linux. (YOU supply this). A soft link to a linux source tree.
e.g. ln -s /usr/src/linux linux
We should, but do not, have a HOWTO for each target. Sorry, Ron's fault.
But the SIS 630 is a good place to start.
To make this you need a newer GAS. Our version that works is
GNU assembler version 2.9.5 (i386-redhat-linux) using BFD version
2.9.5.0.22
This comes with redhat 6.2.
This comes with redhat 6.2 or later. Almost everybody has this now.
To build, cd to the directory and make, viz.
cd linuxbios/PM133
make
You'll see the various compiles, then you'll see an ld step, then a step
called mkrom. mkrom builds a 64k linuxbios rom image. Finally the
linuxbios 64k image is concatenated with a stripped, compressed linux
kernel and put into a file called 'romimage'.
If you say
make floppy
it will build it and 'mcopy romimage a:'. This is for those of you with
FLASH burners.
-------------------------
LinuxBIOS structure
-------------------------
Mkrom puts in a call to f000:fff0, which is the entry point for LinuxBIOS.
This starts off in source form in crt0.S
There are about 16 instructions of 16-bit code, in the include file
../../chip/intel/intel_start32.S. This is the absolute minimum amount of
assembly code needed.
This puts us into protected mode with 32-bit addresses. Next ram is turned
on. We have tried hard to keep the 32-bit assembly to a minimum, and in
fact what's there is really the little bit needed to get ram going, and
the other little bit needed to print diagnostic messages to COM1 while RAM
is set up. If you don't know it already you'll find getting SDRAM going is
a real mess, though we're getting better at it bit by bit.
The assembly code calls intel_main function (found in
../../chip/intel/intel_main.c). This function does all the remaining
hardware setup in C. Please think hard about adding assembly! We do an
awful lot in C, include cache, MTRR, MSR, and other setup.
Finally, intel_main calls linuxbios_main (../inflate/main.c). This code
unzips the kernel to 0x100000, and jumps to it. From that point on, Linux
runs the show.