{
  description = "Firmware for Sinara Fast-Servo based on Not-OS and Linien";
  
  inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-unstable;
  inputs.not-os.url = github:cleverca22/not-os;
  inputs.not-os.inputs.nixpkgs.follows = "nixpkgs";

  outputs = { self, nixpkgs, not-os }:
    let
      pkgs = import nixpkgs { system = "x86_64-linux"; };
      not-os-cfg = not-os-configured.config.system;

      patched-not-os = pkgs.applyPatches {
        name = "not-os-patched";
        src = not-os;
        patches = [
          ./network.patch
          ./pr-28.patch
          ./pr-29.patch
          ./pr-30.patch
        ];
      };

      gnu-platform = "arm-none-eabi";

      binutils-pkg = { zlib, extraConfigureFlags ? [] }: pkgs.stdenv.mkDerivation rec {
        basename = "binutils";
        version = "2.30";
        name = "${basename}-${gnu-platform}-${version}";
        src = pkgs.fetchurl {
          url = "https://ftp.gnu.org/gnu/binutils/binutils-${version}.tar.bz2";
          sha256 = "028cklfqaab24glva1ks2aqa1zxa6w6xmc8q34zs1sb7h22dxspg";
        };
        configureFlags = [
          "--enable-deterministic-archives"
          "--target=${gnu-platform}"
          "--with-cpu=cortex-a9"
          "--with-fpu=vfpv3"
          "--with-float=hard"
          "--with-mode=thumb"
        ] ++ extraConfigureFlags;
        outputs = [ "out" "info" "man" ];
        depsBuildBuild = [ pkgs.buildPackages.stdenv.cc ];
        buildInputs = [ zlib ];
        enableParallelBuilding = true;
        meta = {
          description = "Tools for manipulating binaries (linker, assembler, etc.)";
          longDescription = ''
            The GNU Binutils are a collection of binary tools.  The main
            ones are `ld' (the GNU linker) and `as' (the GNU assembler).
            They also include the BFD (Binary File Descriptor) library,
            `gprof', `nm', `strip', etc.
          '';
          homepage = http://www.gnu.org/software/binutils/;
          license = pkgs.lib.licenses.gpl3Plus;
          /* Give binutils a lower priority than gcc-wrapper to prevent a
            collision due to the ld/as wrappers/symlinks in the latter. */
          priority = "10";
        };
      };

      gcc-pkg = { gmp, mpfr, libmpc, platform-binutils, extraConfigureFlags ? [] }: pkgs.stdenv.mkDerivation rec {
        basename = "gcc";
        version = "9.1.0";
        name = "${basename}-${gnu-platform}-${version}";
        src = pkgs.fetchurl {
          url = "https://ftp.gnu.org/gnu/gcc/gcc-${version}/gcc-${version}.tar.xz";
          sha256 = "1817nc2bqdc251k0lpc51cimna7v68xjrnvqzvc50q3ax4s6i9kr";
        };
        preConfigure = ''
          mkdir build
          cd build
        '';
        configureScript = "../configure";
        configureFlags = [ 
          "--target=${gnu-platform}"
          "--with-arch=armv7-a"
          "--with-tune=cortex-a9"
          "--with-fpu=vfpv3"
          "--with-float=hard"
          "--disable-libssp"
          "--enable-languages=c"
          "--with-as=${platform-binutils}/bin/${gnu-platform}-as"
          "--with-ld=${platform-binutils}/bin/${gnu-platform}-ld" ] ++ extraConfigureFlags;
        outputs = [ "out" "info" "man" ];
        hardeningDisable = [ "format" "pie" ];
        propagatedBuildInputs = [ gmp mpfr libmpc platform-binutils ];
        enableParallelBuilding = true;
        dontFixup = true;
      };

      newlib-pkg = { platform-binutils, platform-gcc }: pkgs.stdenv.mkDerivation rec {
        pname = "newlib";
        version = "3.1.0";
        src = pkgs.fetchurl {
          url = "ftp://sourceware.org/pub/newlib/newlib-${version}.tar.gz";
          sha256 = "0ahh3n079zjp7d9wynggwrnrs27440aac04340chf1p9476a2kzv";
        };
        nativeBuildInputs = [ platform-binutils platform-gcc ];
        configureFlags = [
          "--target=${gnu-platform}"

          "--with-cpu=cortex-a9"
          "--with-fpu=vfpv3"
          "--with-float=hard"
          "--with-mode=thumb"
          "--enable-interwork"
          "--disable-multilib"

          "--disable-newlib-supplied-syscalls"
          "--with-gnu-ld"
          "--with-gnu-as"
          "--disable-newlib-io-float"
          "--disable-werror"
        ];
        dontFixup = true;
      };
      
      gnutoolchain = rec {
        binutils-bootstrap = pkgs.callPackage binutils-pkg { };
        gcc-bootstrap = pkgs.callPackage gcc-pkg {
          platform-binutils = binutils-bootstrap;
          extraConfigureFlags = [ "--disable-libgcc" ];
        };
        newlib = pkgs.callPackage newlib-pkg {
          platform-binutils = binutils-bootstrap;
          platform-gcc = gcc-bootstrap;
        };
        binutils = pkgs.callPackage binutils-pkg {
          extraConfigureFlags = [ "--with-lib-path=${newlib}/arm-none-eabi/lib" ];
        };
        gcc = pkgs.callPackage gcc-pkg {
          platform-binutils = binutils;
          extraConfigureFlags = [ "--enable-newlib" "--with-headers=${newlib}/arm-none-eabi/include" ];
        };
      };

      mkbootimage = pkgs.stdenv.mkDerivation {
        pname = "mkbootimage";
        version = "2.3dev";

        src = pkgs.fetchFromGitHub {
          owner = "antmicro";
          repo = "zynq-mkbootimage";
          rev = "872363ce32c249f8278cf107bc6d3bdeb38d849f";
          sha256 = "sha256-5FPyAhUWZDwHbqmp9J2ZXTmjaXPz+dzrJMolaNwADHs=";
        };

        propagatedBuildInputs = [ pkgs.libelf pkgs.pcre ];
        patchPhase = ''
          substituteInPlace Makefile --replace "git rev-parse --short HEAD" "echo nix"
        '';
        installPhase = ''
          mkdir -p $out/bin
          cp mkbootimage $out/bin
        '';
        # fix crash; see https://github.com/xmrig/xmrig/issues/3305
        hardeningDisable = [ "fortify" ];
      };

      fsbl = { board ? "zc706" }: pkgs.stdenv.mkDerivation {
        name = "${board}-fsbl";
        src = pkgs.fetchFromGitHub {
          owner = "Xilinx";
          repo = "embeddedsw";
          rev = "65c849ed46c88c67457e1fc742744f96db968ff1";
          sha256 = "1rvl06ha40dzd6s9aa4sylmksh4xb9dqaxq462lffv1fdk342pda";
        };
        patches = [ ./fsbl.patch ];
        nativeBuildInputs = [
          pkgs.gnumake
          gnutoolchain.binutils
          gnutoolchain.gcc
        ];
        patchPhase = ''
          patch -p1 -i ${./fsbl.patch}
          patchShebangs lib/sw_apps/zynq_fsbl/misc/copy_bsp.sh
          echo 'SEARCH_DIR("${gnutoolchain.newlib}/arm-none-eabi/lib");' >> lib/sw_apps/zynq_fsbl/src/lscript.ld
        '';
        buildPhase = ''
          cd lib/sw_apps/zynq_fsbl/src
          make BOARD=${board} "CFLAGS=-DFSBL_DEBUG_INFO -g"
        '';
        installPhase = ''
          mkdir $out
          cp fsbl.elf $out
        '';
        doCheck = false;
        dontFixup = true;
      };

      u-boot = { board ? "zc706" }: pkgs.pkgsCross.armv7l-hf-multiplatform.buildUBoot {
        defconfig = "xilinx_zynq_virt_defconfig";
        patches = [] ++ pkgs.lib.optional (board == "fast-servo") ./fast-servo/u-boot.patch;
        preConfigure = ''
          export DEVICE_TREE=$([ "${board}" = "zc706" ] && echo "zynq-${board}" || echo "${board}")
        '';
        extraConfig = ''
          CONFIG_AUTOBOOT=y
          CONFIG_BOOTCOMMAND="${builtins.replaceStrings [ "\n" ] [ "; " ] ''
            setenv bootargs 'root=/dev/mmcblk0p2 console=ttyPS0,115200n8 systemConfig=${builtins.unsafeDiscardStringContext not-os-cfg.build.toplevel}'
            fatload mmc 0 0x6400000 uImage
            fatload mmc 0 0x8000000 devicetree.dtb
            fatload mmc 0 0xA400000 uRamdisk.image.gz
            bootm 0x6400000 0xA400000 0x8000000
          ''}"
          CONFIG_BOOTDELAY=0
          CONFIG_USE_BOOTCOMMAND=y
        '';
        extraMeta.platforms = [ "armv7l-linux" ];
        filesToInstall = [ "u-boot.elf" ];
      };

      bootimage = { board ? "zc706" }: pkgs.runCommand "${board}-bootimage"
        {
          buildInputs = [ mkbootimage ];
        }
        ''
          bifdir=`mktemp -d`
          cd $bifdir
          ln -s ${fsbl { inherit board; }}/fsbl.elf fsbl.elf
          ln -s ${u-boot { inherit board; }}/u-boot.elf u-boot.elf
          cat > boot.bif << EOF
          the_ROM_image:
          {
            [bootloader]fsbl.elf
            u-boot.elf
          }
          EOF
          mkdir $out $out/nix-support
          mkbootimage boot.bif $out/boot.bin
          echo file binary-dist $out/boot.bin >> $out/nix-support/hydra-build-products
        '';

      # Pinned qemu version due to networking errors in recent version 8.2.0
      qemu = pkgs.qemu.overrideAttrs (oldAttrs: rec {
        version = "8.1.3";
        src = pkgs.fetchurl {
          url = "https://download.qemu.org/qemu-${version}.tar.xz";
          hash = "sha256-Q8wXaAQQVYb3T5A5jzTp+FeH3/QA07ZA2B93efviZbs=";
        };
      });
      
      not-os-configured = (import patched-not-os {
          inherit nixpkgs;
          extraModules = [
            "${patched-not-os}/zynq_image.nix"
          ];
          system = "x86_64-linux";
          crossSystem.system = "armv7l-linux";
        });

      not-os-qemu = { board ? "zc706" }: let
        qemuScript = ''
          #!/bin/bash
          export PATH=${qemu}/bin:$PATH
          IMGDIR=$(mktemp -d /tmp/not-os-qemu-XXXXXX)
          BASE=$(realpath $(dirname $0))
          qemu-img create -F raw -f qcow2 -b $BASE/sd-image.img $IMGDIR/sd-overlay.qcow2 512M

          # Some command arguments are based from samples in Xilinx QEMU User Documentation
          # See: https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/821854273/Running+Bare+Metal+Applications+on+QEMU

          qemu-system-arm \
            -M xilinx-zynq-a9 \
            -serial /dev/null \
            -serial stdio \
            -display none \
            -dtb $BASE/devicetree.dtb \
            -kernel $BASE/uImage \
            -initrd $BASE/uRamdisk.image.gz \
            -drive file=$IMGDIR/sd-overlay.qcow2,if=sd,format=qcow2 \
            -append "root=/dev/mmcblk0p2 console=ttyPS0,115200n8 systemConfig=${builtins.unsafeDiscardStringContext not-os-cfg.build.toplevel}";

          rm -rf $IMGDIR
        '';
        in pkgs.runCommand "not-os-qemu" {
          inherit qemuScript;
          passAsFile = [ "qemuScript" ];
          preferLocalBuild = true;
        }
        ''
          mkdir $out
          cd $out
          cp -s ${not-os-cfg.build.kernel}/uImage .
          cp -s ${not-os-cfg.build.uRamdisk}/initrd uRamdisk.image.gz
          cp -s ${not-os-cfg.build.kernel}/dtbs/zynq-zc706.dtb devicetree.dtb
          cp -s ${sd-image { inherit board; }}/sd-image/sd-image.img .
          ln -sv ${not-os-cfg.build.toplevel} toplevel
          cp $qemuScriptPath qemu-script
          chmod +x qemu-script
          patchShebangs qemu-script
        '';

      sd-image = { board ? "zc706" }: let
        rootfsImage = pkgs.callPackage (pkgs.path + "/nixos/lib/make-ext4-fs.nix") {
          storePaths = [ not-os-cfg.build.toplevel ];
          volumeLabel = "ROOT";
        };
        # Current firmware (kernel, bootimage, etc..) takes ~18MB
        firmwareSize = 30;
        firmwarePartitionOffset = 8;
        in pkgs.stdenv.mkDerivation {
          name = "sd-image";
          nativeBuildInputs = with pkgs; [ dosfstools mtools libfaketime util-linux parted ];
          buildCommand = ''
            mkdir -p $out/nix-support $out/sd-image
            export img=$out/sd-image/sd-image.img

            echo "${pkgs.stdenv.buildPlatform.system}" > $out/nix-support/system
            echo "file sd-image $img" >> $out/nix-support/hydra-build-products

            gap=${toString firmwarePartitionOffset}

            rootSizeBlocks=$(du -B 512 --apparent-size ${rootfsImage} | awk '{ print $1 }')
            firmwareSizeBlocks=$((${toString firmwareSize} * 1024 * 1024 / 512))
            imageSize=$((rootSizeBlocks * 512 + firmwareSizeBlocks * 512 + gap * 1024 * 1024))
            truncate -s $imageSize $img

            fat32Start="$((gap))MB"
            fat32End="$((gap + ${toString firmwareSize}))MB"

            parted $img mklabel msdos
            parted $img mkpart primary fat32 $fat32Start $fat32End
            parted $img mkpart primary ext4 $fat32End 100%
            parted $img set 1 boot on

            eval $(partx $img -o START,SECTORS --nr 2 --pairs)
            dd conv=notrunc if=${rootfsImage} of=$img seek=$START count=$SECTORS

            eval $(partx $img -o START,SECTORS --nr 1 --pairs)
            truncate -s $((SECTORS * 512)) firmware_part.img
            faketime "1970-01-01 00:00:00" mkfs.vfat -n BOOT firmware_part.img

            mkdir firmware
            cp ${bootimage { inherit board; }}/boot.bin firmware/
            cp ${not-os-cfg.build.kernel}/uImage firmware/
            cp ${not-os-cfg.build.uRamdisk}/initrd firmware/uRamdisk.image.gz
            cp ${not-os-cfg.build.kernel}/dtbs/zynq-zc706.dtb firmware/devicetree.dtb

            (cd firmware; mcopy -psvm -i ../firmware_part.img ./* ::)
            dd conv=notrunc if=firmware_part.img of=$img seek=$START count=$SECTORS
          '';
        };
    in rec {
      packages.x86_64-linux = {
        inherit mkbootimage;
      };
      packages.armv7l-linux = {
        zc706-fsbl = fsbl { board = "zc706"; };
        zc706-bootimage = bootimage { board = "zc706"; };
        zc706-u-boot = u-boot { board = "zc706"; };
        zc706-qemu = not-os-qemu { board = "zc706"; };
        zc706-sd-image = sd-image { board = "zc706"; };
        zc706-not-os = not-os-cfg.build.zynq_image;
        fast-servo-u-boot = u-boot { board = "fast-servo"; };
      };
      hydraJobs = packages.x86_64-linux // packages.armv7l-linux;
    };

  nixConfig = {
    allow-import-from-derivation = true;
  };
}