liminix-fork/modules/outputs/tftpbootlz.nix
Daniel Barlow c7b2733bea tftpbootlz: put command line in dtb
this makes boot.scr substantially shorter, in anticipation of using it
for first boot of the omnia and not wanting to embed an essay in
a setenv value
2023-12-22 20:09:44 +00:00

94 lines
3.4 KiB
Nix

{
config
, pkgs
, lib
, ...
}:
let
inherit (lib) mkOption types concatStringsSep;
inherit (pkgs.lib.trivial) toHexString;
o = config.system.outputs;
cmdline = concatStringsSep " " config.boot.commandLine;
cfg = config.boot.tftp;
tftpbootlz =
pkgs.buildPackages.runCommand "tftpbootlz" {
nativeBuildInputs = with pkgs.pkgsBuildBuild; [ lzma dtc ];
} ''
binsize() { local s=$(stat -L -c %s $1); echo $(($s + 0x1000 &(~0xfff))); }
binsize64k() { local s=$(stat -L -c %s $1); echo $(($s + 0x10000 &(~0xffff))); }
hex() { printf "0x%x" $1; }
kernelStart=${toString cfg.loadAddress}
kernelSize=$(binsize ${o.zimage})
mkdir -p $out
cat ${o.dtb} > $out/dtb
fdtput -p -t lx $out/dtb /reserved-memory '#address-cells' 1
fdtput -t lx $out/dtb /reserved-memory '#size-cells' 1
fdtput $out/dtb /reserved-memory ranges
fdtput -p -t s $out/dtb /reserved-memory/phram-rootfs compatible phram
# can't calculate the actual address here until we know how
# big the dtb will be
fdtput -t lx $out/dtb /reserved-memory/phram-rootfs reg 0xdead 0xcafe
cmd="liminix ${cmdline} mtdparts=phram0:999999999999(rootfs) phram.phram=phram0,999999999999,999999999999,${toString config.hardware.flash.eraseBlockSize} root=/dev/mtdblock0";
fdtput -t s $out/dtb /chosen bootargs "$cmd"
dtbStart=$(($kernelStart + $kernelSize))
dtbSize=$(binsize $out/dtb)
rootfsOrigSize=$(binsize64k ${o.rootfs})
lzma -z9cv ${o.rootfs} > $out/rootfs.lz
rootfsLzSize=$(binsize $out/rootfs.lz)
rootfsLzStart=$(($dtbStart + $dtbSize))
rootfsOrigStart=$(($rootfsLzStart + $rootfsLzSize))
fdtput -t lx $out/dtb /reserved-memory/phram-rootfs reg $(printf "%x" $rootfsOrigStart) $(printf "%x" $rootfsOrigSize)
cmd="liminix ${cmdline} mtdparts=phram0:''${rootfsOrigSize}(rootfs) phram.phram=phram0,''${rootfsOrigStart},''${rootfsOrigSize},${toString config.hardware.flash.eraseBlockSize} root=/dev/mtdblock0";
fdtput -t s $out/dtb /chosen bootargs "$cmd"
# dtc -I dtb -O dts -o /dev/stdout $out/dtb | grep -A10 reserved-memory; exit 1
(cd $out;
ln -s ${o.zimage} zImage
ln -s ${o.manifest} manifest
ln -s ${o.kernel.headers} build)
cat > $out/boot.scr << EOF
setenv serverip ${cfg.serverip}
setenv ipaddr ${cfg.ipaddr}
tftpboot $(hex $kernelStart) result/zImage; tftpboot $(hex $dtbStart) result/dtb ; tftpboot $(hex $rootfsLzStart) result/rootfs.lz
lzmadec $(hex $rootfsLzStart) $(hex $rootfsOrigStart)
bootz $(hex $kernelStart) - $(hex $dtbStart)
EOF
'';
in {
imports = [ ../ramdisk.nix ];
options.boot.tftp.freeSpaceBytes = mkOption {
type = types.int;
default = 0;
};
options.system.outputs = {
tftpbootlz = mkOption {
type = types.package;
description = ''
tftpbootlz
**********
This is a variant of the tftpboot output intended for the
Turris Omnia. It uses a zImage instead of a uimage, as a
workaround for an awkwardly low CONFIG_SYS_BOOTM_LEN setting
in the U-Boot build for the device which means it won't boot
uimages unless they're teeny tiny.
As a bonus, it also uses lzma compression on the rootfs,
which reduces a 20MB ext4 image to around 4MB
'';
};
};
config = {
boot.ramdisk.enable = true;
system.outputs = {
inherit tftpbootlz;
};
};
}