liminix/pkgs/kernel/uimage.nix
Raito Bezarius 0a8343be66 pkgs/kernel/uimage: introduce commandLineDtbNode
Certain devices like the Zyxel NWA50AX will pass information on the command-line
to explain what is the current image (`bootImage=1` vs. `bootImage=0`).

Unfortunately, if we set the `chosen/bootargs` node, this will be overridden forcibly
by U-Boot.

To avoid this problem, it's easier to simply just use another DTB node like `bootargs-override` which
is what OpenWRT does [1].

[1]: https://git.openwrt.org/?p=openwrt/openwrt.git;a=blob;f=target/linux/ramips/patches-5.15/314-MIPS-add-bootargs-override-property.patch;h=e7dca7af886e8c0b69ba2b23f5855ddfeeb0d4a1;hb=refs/heads/main

Signed-off-by: Raito Bezarius <masterancpp@gmail.com>
2024-02-18 20:30:41 +01:00

80 lines
2.2 KiB
Nix

{
lzma
, stdenv
, ubootTools
, dtc
, lib
} :
let
objcopy = "${stdenv.cc.bintools.targetPrefix}objcopy";
arch = stdenv.hostPlatform.linuxArch;
stripAndZip = ''
${objcopy} -O binary -R .reginfo -R .notes -R .note -R .comment -R .mdebug -R .note.gnu.build-id -S vmlinux.elf vmlinux.bin
rm -f vmlinux.bin.lzma ; lzma -k -z vmlinux.bin
'';
in {
kernel
, commandLine
, commandLineDtbNode ? "bootargs"
, entryPoint
, extraName ? "" # e.g. socFamily
, loadAddress
, imageFormat
, dtb ? null
} : stdenv.mkDerivation {
name = "kernel.image";
phases = [
"preparePhase"
(if commandLine != null then assert dtb != null; "mungeDtbPhase" else ":")
(if imageFormat == "fit" then "buildPhaseFIT" else "buildPhaseUImage")
"installPhase"
];
nativeBuildInputs = [
lzma
dtc
stdenv.cc
ubootTools
];
preparePhase = ''
cp ${kernel} vmlinux.elf; chmod +w vmlinux.elf
'';
mungeDtbPhase = ''
dtc -I dtb -O dts -o tmp.dts ${dtb}
echo '/{ chosen { ${commandLineDtbNode} = ${builtins.toJSON commandLine}; }; };' >> tmp.dts
dtc -I dts -O dtb -o tmp.dtb tmp.dts
'';
buildPhaseUImage = ''
test -f tmp.dtb && ${objcopy} --update-section .appended_dtb=tmp.dtb vmlinux.elf || ${objcopy} --add-section .appended_dtb=tmp.dtb vmlinux.elf
${stripAndZip}
mkimage -A ${arch} -O linux -T kernel -C lzma -a 0x${lib.toHexString loadAddress} -e 0x${lib.toHexString entryPoint} -n '${lib.toUpper arch} Liminix Linux ${extraName}' -d vmlinux.bin.lzma kernel.uimage
'';
buildPhaseFIT = ''
${stripAndZip}
cat ${./kernel_fdt.its} > mkimage.its
cat << _VARS >> mkimage.its
/ {
images {
kernel {
data = /incbin/("./vmlinux.bin.lzma");
load = <0x${lib.toHexString loadAddress}>;
entry = <0x${lib.toHexString entryPoint}>;
arch = "${arch}";
compression = "lzma";
};
fdt-1 {
data = /incbin/("./tmp.dtb");
arch = "${arch}";
};
};
};
_VARS
mkimage -f mkimage.its kernel.uimage
mkimage -l kernel.uimage
'';
installPhase = ''
cp kernel.uimage $out
'';
}