uboot: add Librecomputer CC custom build

Add a new U-boot flavor for LibreComputer's AML-S905X-CC (Le Potato).

Board's SoC is based on Trusted Firmware-A architecture and needs extra
closed-source early bootloaders to be combined with U-boot in order to
boot properly, similar to Odroid-C2 board.

Proprietary blobs and related tooling are fetched from
github.com/LibreELEC/amlogic-boot-fip and used in postBuild along with
build output.

Hardware: https://libre.computer/products/aml-s905x-cc/
U-boot doc: https://u-boot.readthedocs.io/en/latest/board/amlogic/libretech-cc.html

pkgs/misc/uboot/default.nix

@@ -211,6 +211,47 @@ in {
     '';
   };
 
+  # Flashing instructions:
+  # dd if=u-boot.gxl.sd.bin of=<sdcard> conv=fsync,notrunc bs=512 skip=1 seek=1
+  # dd if=u-boot.gxl.sd.bin of=<sdcard> conv=fsync,notrunc bs=1 count=444
+  ubootLibreTechCC = let
+    firmwareImagePkg = fetchFromGitHub {
+      owner = "LibreELEC";
+      repo = "amlogic-boot-fip";
+      rev = "4369a138ca24c5ab932b8cbd1af4504570b709df";
+      sha256 = "sha256-mGRUwdh3nW4gBwWIYHJGjzkezHxABwcwk/1gVRis7Tc=";
+      meta.license = lib.licenses.unfreeRedistributableFirmware;
+    };
+  in
+  assert stdenv.buildPlatform.system == "x86_64-linux"; # aml_encrypt_gxl is a x86_64 binary
+  buildUBoot {
+    defconfig = "libretech-cc_defconfig";
+    extraMeta.platforms = ["aarch64-linux"];
+    filesToInstall = ["u-boot.bin"];
+    postBuild = ''
+      # Copy binary files & tools from LibreELEC/amlogic-boot-fip, and u-boot build to working dir
+      mkdir $out tmp
+      cp ${firmwareImagePkg}/lepotato/{acs.bin,bl2.bin,bl21.bin,bl30.bin,bl301.bin,bl31.img} \
+         ${firmwareImagePkg}/lepotato/{acs_tool.py,aml_encrypt_gxl,blx_fix.sh} \
+         u-boot.bin tmp/
+      cd tmp
+      python3 acs_tool.py bl2.bin bl2_acs.bin acs.bin 0
+
+      bash -e blx_fix.sh bl2_acs.bin zero bl2_zero.bin bl21.bin bl21_zero.bin bl2_new.bin bl2
+      [ -f zero ] && rm zero
+
+      bash -e blx_fix.sh bl30.bin zero bl30_zero.bin bl301.bin bl301_zero.bin bl30_new.bin bl30
+      [ -f zero ] && rm zero
+
+      ./aml_encrypt_gxl --bl2sig --input bl2_new.bin --output bl2.n.bin.sig
+      ./aml_encrypt_gxl --bl3enc --input bl30_new.bin --output bl30_new.bin.enc
+      ./aml_encrypt_gxl --bl3enc --input bl31.img --output bl31.img.enc
+      ./aml_encrypt_gxl --bl3enc --input u-boot.bin --output bl33.bin.enc
+      ./aml_encrypt_gxl --bootmk --output $out/u-boot.gxl \
+        --bl2 bl2.n.bin.sig --bl30 bl30_new.bin.enc --bl31 bl31.img.enc --bl33 bl33.bin.enc
+    '';
+  };
+
   ubootNanoPCT4 = buildUBoot rec {
     rkbin = fetchFromGitHub {
       owner = "armbian";

pkgs/top-level/all-packages.nix

@@ -25939,6 +25939,7 @@ with pkgs;
     ubootCubieboard2
     ubootGuruplug
     ubootJetsonTK1
+    ubootLibreTechCC
     ubootNanoPCT4
     ubootNovena
     ubootOdroidC2