From a3f6234ef0674cd9327914aab16de400cad6fcdc Mon Sep 17 00:00:00 2001
From: Arnout Engelen <arnout@bzzt.net>
Date: Thu, 2 Jan 2025 09:46:34 +0100
Subject: [PATCH] WIP: create a FIT image for TFTP booting

TODO: make 'traditional' and FIT methods work side-by-side
---
 modules/outputs/tftpboot.nix | 45 +++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/modules/outputs/tftpboot.nix b/modules/outputs/tftpboot.nix
index 9c6d038..33dcb5e 100644
--- a/modules/outputs/tftpboot.nix
+++ b/modules/outputs/tftpboot.nix
@@ -73,6 +73,7 @@ in {
           cmdline = concatStringsSep " " config.boot.commandLine;
           objcopy = "${pkgs.stdenv.cc.bintools.targetPrefix}objcopy";
           stripAndZip = ''
+            cp vmlinux vmlinux.elf; chmod +w vmlinux.elf
             ${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
           '';
@@ -96,7 +97,7 @@ in {
             # decompression code will assume that any memory after the
             # end of the kernel is free
 
-            dtbStart=$(($rootfsStart + $rootfsSize))
+            imageStart=$(($rootfsStart + $rootfsSize))
             ${if cfg.compressRoot
               then ''
                 lzma -z9cv ${o.rootfs} > rootfs.lz
@@ -127,22 +128,30 @@ in {
 
             dtbSize=$(binsize ./dtb )
 
-            ${if cfg.appendDTB then ''
-              imageStart=$dtbStart
-              # re-package image with updated dtb
-              cat ${o.kernel} > vmlinux.elf
-              ${objcopy} --update-section .appended_dtb=dtb vmlinux.elf
-              ${stripAndZip}
-              mkimage -A ${arch} -O linux -T kernel -C lzma -a $(hex ${toString hw.loadAddress}) -e $(hex ${toString hw.entryPoint}) -n '${lib.toUpper arch} Liminix Linux tftpboot' -d vmlinux.bin.lzma image
-              # dtc -I dtb -O dts -o /dev/stdout dtb | grep -A10 chosen ; exit 1
-              tftpcmd="tftpboot $(hex $imageStart) result/image "
-              bootcmd="bootm $(hex $imageStart)"
-            '' else ''
-              imageStart=$(($dtbStart + $dtbSize))
-              tftpcmd="tftpboot $(hex $imageStart) result/image; tftpboot $(hex $dtbStart) result/dtb "
-              ln -s ${image} image
-              bootcmd="${bootCommand} $(hex $imageStart) - $(hex $dtbStart)"
-            ''}
+            ${stripAndZip}
+            cat ${../../pkgs/kernel/kernel_fdt.its} > mkimage.its
+cat << _VARS  >> mkimage.its
+/ {
+    images {
+        kernel {
+            description = "${arch} Liminix kernel";
+            data = /incbin/("./vmlinux.bin.lzma");
+            load = <0x${lib.toHexString hw.loadAddress}>;
+            entry = <0x${lib.toHexString hw.entryPoint}>;
+            arch = "${arch}";
+            compression = "lzma";
+        };
+        fdt-1 {
+            description = "${arch} Liminix DTB";
+            data = /incbin/("./dtb");
+            arch = "${arch}";
+        };
+    };
+};
+_VARS
+    mkimage -f mkimage.its image
+            tftpcmd="tftpboot $(hex $imageStart) result/image "
+            bootcmd="bootm $(hex $imageStart)"
 
             cat > boot.scr << EOF
             setenv serverip ${cfg.serverip}
@@ -156,7 +165,7 @@ in {
               then "lzmadec $(hex $rootfsLzStart)  $(hex $rootfsStart); "
               else ""
              } $bootcmd
-            EOF
+EOF
          '';
 
     };