Difference between revisions of "Board:tyan/s2892"

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* s2892vBIOS.bin (36K)
* s2892vBIOS.bin (36K)


WARNING: I have a bios savior so that when I mess up I can get my machine back.  If you don't have one, you might not want to do the fallback only boot.
If you want to simplify the build process and just do what I did:


# git clone git://dev.laptop.org/users/jcrouse/buildrom
# apply this patch [[64-bit buildrom patch]]
# make (it will fail)
# copy this [[resolve.S for 64-bit]] file to buildrom/work/uclibc/uClibc-0.9.28/ldso/ldso/x86_64/resolve.S
# make
# use payloads from deploy directory.


WARNING: I have a bios savior so that when I mess up I can get my machine back.  If you don't have one, you might not want to do the fallback only boot.


== Config.lb ==
== Config.lb ==

Revision as of 18:38, 30 October 2006

Purpose

Customize the system to allow me to play with memory mappings and large devices. I wanted to minimize intermediate steps from LinuxBIOS to Linux to minimize the areas of expertise I needed to develop. I also wanted to be able to use the SATA drives as my boot drives.

Disclaimer

There are several places where my solutions are not as elegant as I wished them to be. Suggestions are welcome.

Current set up

  • Tyan s2892
  • LinuxBIOS with Linux 2.6.18-tiny as a payload

The procedure

I started by installing LinuxBIOS on the system and using FILO and Etherboot to boot to a kernel. This allowed me to try the different payloads without flashing every time.

Next I downloaded the OLPC buildrom

git clone git://dev.laptop.org/users/jcrouse/buildrom

I modified the Config.mk to include pciutils from

http://buildroot.uclibc.org/cgi-bin/viewcvs.cgi/trunk/buildroot/package/

and took out the graphical boot menu. I also modified buildrom/skeleton/devices.txt to add lines for my hard drives. I just copied the lines for sda and sda1 and made hda hda1 hda2 and sda2. The important thing is to make sure that the major and minor numbers are correct.

I modified buildrom/skeleton/linuxrc so that the device files were created earlier, /dev/null didn't become a text file, and my drives got mounted in read-only mode.

I then modified buildrom/skeleton/bin/boot.functions so that doboot() called my script on the hard drive for the kexec. That's nice to avoid flashing the BIOS for booting different kernels.

I downloaded Linux 2.6.18.1 (2.6.18-rc4 had some problems with SATA) and patched it with the tiny patches that came with OLPC. 12-tiny-tiny-crc.patch fails, but was easy to apply by hand.

I configured the kernel to include support for ext2, SATA, and IDE.

I ran make and copied the payloads from the buildrom/deploy directory to my s2892 to be used. olpc-payload.elf.lzma (732K) is used for booting directly from LinuxBIOS, and olpc-payload-uncompressed.elf (1.7M) was useful for testing it with FILO and Etherboot.

mkelfImage wouldn't work with the vmlinux file, so I changed the Makefile to get it to use the bzImage instead.

Now I have

  • fallback/linuxbios.strip (88K)
  • normal/payload (860K)
  • s2892vBIOS.bin (36K)

If you want to simplify the build process and just do what I did:

  1. git clone git://dev.laptop.org/users/jcrouse/buildrom
  2. apply this patch 64-bit buildrom patch
  3. make (it will fail)
  4. copy this resolve.S for 64-bit file to buildrom/work/uclibc/uClibc-0.9.28/ldso/ldso/x86_64/resolve.S
  5. make
  6. use payloads from deploy directory.

WARNING: I have a bios savior so that when I mess up I can get my machine back. If you don't have one, you might not want to do the fallback only boot.

Config.lb

# Sample config file for
# the Tyan s2892
# This will make a target directory of ./s2892

target s2892
mainboard tyan/s2892

option ROM_SIZE      = 0xf7000 # 8Mbit - 36K for VGA BIOS

option CONFIG_ROM_STREAM=1

option CONFIG_CONSOLE_SERIAL8250 = 1
option CONFIG_CONSOLE_VGA = 1
option FALLBACK_SIZE = ROM_SIZE
option ROM_IMAGE_SIZE = 0x16000

# Tyan s2892
romimage "fallback"
        option CONFIG_COMPRESSED_ROM_STREAM_LZMA=1
        option CONFIG_PRECOMPRESSED_ROM_STREAM=1
        option USE_FALLBACK_IMAGE=1
        option LINUXBIOS_EXTRA_VERSION="$(shell cat ../../VERSION)_Fallback"
        payload ../olpc-payload.elf.lzma
end

buildrom ./linuxbios.rom ROM_SIZE "fallback"


Kexec-tools

Because the kexec tools that are included with OLPC's buildrom are stripped down for 32-bit kernels, I built kexec statically linked (read "large file") and put it on the hard drive with the kernel to be loaded. I use kexec to boot my kernel which has been combined with initrd into an elf with mkelfImage:

mkelfImage --comand--line="ro root=/dev/hda1 console=tty0" --kernel="" --initrd="" --output="mylinux.elf"

I have to use

kexec -f mylinux.elf 

because otherwise kexec calls shutdown and there is no shutdown in the OLPC initrd. I guess that's a half truth, because when I call kexec without the -f it reboots the machine completely instead of a kexec when shutdown is available.

Status

My machine boots LinuxBIOS, then linux-2.6.18.1-tiny, then kexecs into linux-2.6.18.1-normal. It takes a little longer than going through elfboot and FILO, but it is a simpler path.

Author

This document was written by Myles Watson <myles at pel dot cs dot byu dot edu>