Something

#!/bin/bash

# unless otherwise noted, EVERY NUMBER IS IN HEX

base_dir=$(dirname $0)

scriptfile=autoscript.scr
imgfile=autoscript.bin

kernel_file=uImage
for i in $base_dir/omap5912osk/uImage* ; do
    cp -f $i $base_dir/$kernel_file
done
if [ ! -f $base_dir/$kernel_file ] ; then
    echo "Could not find kernel image $base_dir/$kernel_file."
    exit 1
fi
kernel_size_10=`du -b $base_dir/$kernel_file | cut -f 1`
kernel_size=$( printf "0x%08X" $kernel_size_10 )

rootfs_file=rootfs.jffs2
#cp -f $base_dir/omap5912osk/gpe-image-omap5912osk.jffs2 $base_dir/$rootfs_file
cp -f $base_dir/omap5912osk/pd-osk-gpe-image-omap5912osk.jffs2 $base_dir/$rootfs_file
if [ ! -f $base_dir/$rootfs_file ] ; then
    echo "Could not find root filesystem image $base_dir/$rootfs_file."
    exit 1
fi
rootfs_size_10=`du -b $base_dir/$rootfs_file | cut -f 1`
rootfs_size=$( printf "0x%08X" $rootfs_size_10 )

# the osk doesn't have enough RAM to copy the whole rfs with tftp
# thus we must split it
# this makes files named rootfs.jffs2.00, rootfs.jffs2.01, ...
max_file_size=0x00C00000 # 12 MiB
split --bytes $(($max_file_size)) --numeric-suffixes $rootfs_file ${rootfs_file}.


# because this may get confusing, here is a description of interpolation rules
# here documents work basically like double quoted strings w.r.t. variable expansion
# $var is local to this script, and will be expanded before catting
# \${var} is not expanded here, but will be expanded when the generated script is run in u-boot
# like in a double quoted string, single quotes don't have any special meaning (w.r.t. this script)
# in u-boot, single quote do not expand variables, so
#    setenv bar blah
#    setenv foo '${bar}'
#    setenv fu ${bar}
# means that foo is literally "${bar}" and fu is literally "blah"
# variables are expanded only once, so "setenv baz ${foo}" means baz = "${bar}"

# basically,
# $var is a literal in u-boot
# \${var} is "${var}" in u-boot
# "setenv foo \${var}" or "setenv foo '${var}'" makes foo the unexpanded ${var} in u-boot
# almost everything except constants (addresses and such) should be of the form \${var}
# so they get expanded when they're used.
# use this regex to check: [^\\][$]
# isn't quoting fun?  bonus points if you can quine this script

# note about bootargs
# it seems that bootargs is not expanded before being passed to the kernel,
# so we must not have any unexpanded variables in it

# 0x00000000-0x00020000 : "bootloader"
# 0x00020000-0x00040000 : "params"
# 0x00040000-0x00240000 : "kernel"
# 0x00240000-0x02000000 : "filesystem"

(cat <<EOF

echo
echo addresses and sizes
echo

setenv tmp 0x10000000

setenv kernel_flash_addr 0x00040000
print kernel_flash_addr
setenv kernel_flash_endaddr 0x0023FFFF
print kernel_flash_endaddr

setenv rootfs_flash_addr 0x00240000
print rootfs_flash_addr
setenv rootfs1_flash_addr 0x00240000
setenv rootfs2_flash_addr 0x00E40000
setenv rootfs_flash_endaddr 0x01FFFFFF
print rootfs_flash_endaddr


echo
echo tftp
echo

setenv ipaddr 192.168.0.187
print ipaddr
setenv serverip 192.168.0.23
print serverip
setenv gatewayip 192.168.0.3
print gatewayip
setenv netmask 255.255.255.0
print netmask


echo
echo erase flash
echo

setenv erase_kernel_flash 'erase \${kernel_flash_addr} \${kernel_flash_endaddr}'
print erase_kernel_flash
setenv erase_rootfs_flash 'erase \${rootfs_flash_addr} \${rootfs_flash_endaddr}'
print erase_kernel_flash


echo
echo download
echo

setenv kernel_file ${kernel_file}
print kernel_file
setenv get_kernel 'run erase_kernel_flash; tftp \${tmp} \${kernel_file}; cp.b \${fileaddr} \${kernel_flash_addr} \${filesize}'
print get_kernel

setenv rootfs_file ${rootfs_file}
print rootfs_file
setenv get_rootfs1 'tftp \${tmp} \${rootfs_file}.00; cp.b \${fileaddr} \${rootfs1_flash_addr} \${filesize}'
setenv get_rootfs2 'tftp \${tmp} \${rootfs_file}.01; cp.b \${fileaddr} \${rootfs2_flash_addr} \${filesize}'
setenv get_rootfs 'run erase_rootfs_flash; run get_rootfs1; run get_rootfs2'
print get_rootfs

setenv get_system 'run get_kernel; run get_rootfs'
print get_system


echo
echo boot commands
echo

setenv bootargs console=ttyS0,115200n8 noinitrd rw ip=dhcp root=/dev/mtdblock3 rootfstype=jffs2 mem=32M
print bootargs

setenv bootcmd 'bootm \${kernel_flash_addr}'
print bootcmd


echo
echo update
echo

setenv autoscript_file ${imgfile}
print autoscript_file

setenv update_env 'tftp \${tmp} \${autoscript_file}; autoscr \${fileaddr}'
printenv update_env


echo
echo saving env...
echo

saveenv

EOF
) > $base_dir/$scriptfile

mkimage -A arm -O linux -T script -C none -a 0 -e 0 \
    -n "kernel/fs loader script" \
    -d $base_dir/$scriptfile $base_dir/$imgfile

chmod 644 $base_dir/$imgfile
chmod 644 $base_dir/$kernel_file
chmod 644 $base_dir/$rootfs_file