liminix/modules/tftpboot.nix

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{
config
, pkgs
, lib
, ...
}:
let
inherit (lib) mkOption types concatStringsSep;
cfg = config.boot.tftp;
in {
imports = [ ./ramdisk.nix ];
options.boot.tftp.freeSpaceBytes = mkOption {
type = types.int;
default = 0;
};
options.system.outputs = {
tftpboot = mkOption {
type = types.package;
description = ''
Directory containing files needed for TFTP booting
'';
};
boot-scr = mkOption {
type = types.package;
description = ''
U-Boot commands to load and boot a kernel and rootfs over TFTP.
Copy-paste into the device boot monitor
'';
};
};
config = {
boot.ramdisk.enable = true;
system.outputs = rec {
tftpboot =
let o = config.system.outputs; in
pkgs.runCommand "tftpboot" {} ''
mkdir $out
cd $out
ln -s ${o.rootfs} rootfs
ln -s ${o.kernel} vmlinux
ln -s ${o.manifest} manifest
ln -s ${o.kernel.headers} build
ln -s ${o.uimage} uimage
ln -s ${o.boot-scr}/dtb dtb
ln -s ${o.boot-scr}/script boot.scr
'';
boot-scr =
let
inherit (pkgs.lib.trivial) toHexString;
o = config.system.outputs;
cmdline = concatStringsSep " " config.boot.commandLine;
in
pkgs.buildPackages.runCommand "boot-scr" { nativeBuildInputs = [ pkgs.pkgsBuildBuild.dtc ]; } ''
uimageSize=$(($(stat -L -c %s ${o.uimage}) + 0x1000 &(~0xfff)))
rootfsStart=0x$(printf %x $((${cfg.loadAddress} + 0x100000 + $uimageSize &(~0xfffff) )))
rootfsBytes=$(($(stat -L -c %s ${o.rootfs}) + 0x100000 &(~0xfffff)))
rootfsBytes=$(($rootfsBytes + ${toString cfg.freeSpaceBytes} ))
rootfsMb=$(($rootfsBytes >> 20))
cmd="mtdparts=phram0:''${rootfsMb}M(rootfs) phram.phram=phram0,''${rootfsStart},''${rootfsBytes},${config.hardware.flash.eraseBlockSize} root=/dev/mtdblock0";
dtbStart=$(printf %x $((${cfg.loadAddress} + $rootfsBytes + 0x100000 + $uimageSize )))
mkdir $out
cat ${o.dtb} > $out/dtb
fdtput -p -t s $out/dtb /reserved-memory/phram-rootfs compatible phram
fdtput -p -t lx $out/dtb /reserved-memory/phram-rootfs reg 0 $rootfsStart 0 $(printf %x $rootfsBytes)
dtbBytes=$(($(stat -L -c %s $out/dtb) + 0x1000 &(~0xfff)))
cat > $out/script << EOF
setenv serverip ${cfg.serverip}
setenv ipaddr ${cfg.ipaddr}
setenv bootargs 'liminix ${cmdline} $cmd'
tftpboot 0x$(printf %x ${cfg.loadAddress}) result/uimage ; tftpboot 0x$(printf %x $rootfsStart) result/rootfs ; tftpboot 0x$dtbStart result/dtb
bootm 0x$(printf %x ${cfg.loadAddress}) - 0x$dtbStart
EOF
'';
};
};
}