16xcfg is a utility written in 'C' which is used to configure a kernel
image, prior to booting it on a VME board.  It is so named because it was
developed first for Morotola MVME16x boards, but can now also be used for
kernels on BVM boards, and MVME147 boards.

The utility does four things:

a) It patches a start address and initial stack pointer in to the kernel at
   address zero, making it start with a standard 680x0 exception table
   format.

b) It patches boot parameters (eg memory size, CPU type, root device, etc)
   in to the kernel image at address 0x100.  It uses one of two formats for
   these parameters, depending on whether this is a 2.0.xx or a 2.1.xx
   kernel.

c) It patches a code module, known as loader.bin, in to the image at address
   0x800.  To start a kernel you have to execute code from 0x800.  This
   module is necessary because the kernel image is an ELF format file, and
   something needs to move the various sections of the file to the correct
   addresses, and zero workspace, before starting the kernel proper.
   loader.bin also moves the boot parameters from 0x100 to the end of the
   relocated kernel image, where the kernel startup code expects to find
   them.

d) Optionally, as of version 5, it combines a kernel and a ramdisk in to
   one single boot file.  Parameters relating to the ramdisk are patched
   in at offset 0x200.

16xcfg.c is written to be little/big endian independent, so it can be run
on, say, a 386 or a 680x0 system.

You compile 16xcfg.c with a command such as "cc -o 16xcfg 16xcfg.c", and can
run it with '-h' for an option summary:

>  # ./16xcfg -h
>  -- 16xcfg/16xcfg version 5 --
>  
>  Usage:  16xcfg/16xcfg [options]
>          -a <answers>    File with answers to use
>          -d <defaults>   File with default answers
>          -k <kernel>     Kernel file to patch
>          -l <loader>     Loader file
>          -s <save>       File to save answers
>          -r <ramdisk>    RamDisk image to append to kernel
>  
>  Defaults are '-k vmlinux -l loader.bin'
>  
>  #

When you run 16xcfg it presents you with a series of questions, and for each
one gives you a choice of possible answers and a default answer.  Pressing
return will select the default answer.  It can save your answers to a file
(option -s), which you can then use later as new defaults (option -d).  The
'-a' option runs 16xcfg without prompting.  The configuration files produced
by 16xcfg are simple text files and can be editted by any means, provided
you preserve the format.

An example run, showing default answers typical of those for a BVME6000
board is shown below:

>  # ./16xcfg -l loader.bin -d bvm20.cfg -k vmlinux-2033pl1a
>  Kernel (2.0,2.1) [2.0]?                           
>  Machine (MVME131,MVME147,MVME162,MVME167,BVME6000) [BVME6000]?    
>  CPU type (68020,68030,68040,68060) [68060]?                   
>  FPU present (No,Yes) [Yes]?                       
>  RAM size [0x00800000]?                            
>  RAMDISK base (0 for none) [0x00000000]?           
>  Cmndline parameters [root=/dev/sda1 ro]? 
>  #

Example answers for an MVME147 booting from a ramdisk might be:

KERNEL    2.0
MACHINE   MVME147
CPUTYPE   68030
FPU       Yes
RAMSIZE   0x01000000
RDBASE    0x00e00000
RDSIZE    0x001c2000
CMNDLINE  root=/dev/ramdisk init=/bin/sh

For a 2.1.xx kernel there are fewer choices for 'Machine', as the same
kernel can run on an MVME162 and an MVME167.

Command line parameters for a 2.0.xx kernel are typically

	root=/dev/sda1 ro

for a root file system on a local disk, or

	root=/dev/nfs nfsroot=/tftpboot/debian-fs nfsaddrs=10.1.1.9:10.1.1.1:::nfs68k::none

for an NFS mounted root file system.

Command line parameters for a 2.1.xx kernel are typically

	root=/dev/sda1 ro console=ttyS0,19200

for a root file system on a local disk, or

	root=/dev/nfs nfsroot=10.1.1.1:/tftpboot/debian-fs ip=10.1.1.9:10.1.1.1:::nfs68k::off ro console=ttyS0,19200

for an NFS mounted root file system.

Refer to linux/Documentation/nfsroot.txt in the relevant kernel source tree
for details of the parameter fields.

For either kernel, the following options to the scsi driver may be of use:

	53c7xx=nosync:0,nodisconnect:0

Append those to the command line if you experience SCSI related problems.

To create a combined ramdisk and kernel file, you must specify the
ramdisk filename with '-r', and you must provide ramdisk base and
ramdisk length parameters to the appropriate questions.

16xcfg only works with uncompressed kernels and ramdisk images.

Last updated 981212.

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