From 1aee5344a5a230e26e60f01664eb01844f7c5e07 Mon Sep 17 00:00:00 2001
From: Florian Agbuya <fa@m-labs.ph>
Date: Fri, 15 Dec 2023 15:34:41 +0800
Subject: [PATCH] flake: add not-os disk image builder and qemu

---
 flake.nix | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 99 insertions(+), 3 deletions(-)

diff --git a/flake.nix b/flake.nix
index ac631ba..0e14ea5 100644
--- a/flake.nix
+++ b/flake.nix
@@ -8,6 +8,7 @@
   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";
@@ -194,10 +195,10 @@
         extraConfig = ''
           CONFIG_AUTOBOOT=y
           CONFIG_BOOTCOMMAND="${builtins.replaceStrings [ "\n" ] [ "; " ] ''
-            setenv bootargs 'root=/dev/mmcblk0p2 console=ttyPS0,115200n8 systemConfig=${builtins.unsafeDiscardStringContext not-os-configured.config.system.build.toplevel}'
+            setenv bootargs 'root=/dev/mmcblk0p2 console=ttyPS0,115200n8 systemConfig=${builtins.unsafeDiscardStringContext not-os-cfg.build.toplevel}'
             fatload mmc 0 0x6400000 uImage
             fatload mmc 0 0x8000000 devicetree.dtb
-            fatload mmc 0 0xA400000 uramdisk.image.gz
+            fatload mmc 0 0xA400000 uRamdisk.image.gz
             bootm 0x6400000 0xA400000 0x8000000
           ''}"
           CONFIG_BOOTDELAY=0
@@ -236,6 +237,99 @@
           system = "x86_64-linux";
           crossSystem.system = "armv7l-linux";
         });
+
+      not-os-qemu = { board ? "zc706" }: let
+        qemuScript = ''
+          #!/bin/bash
+          export PATH=${pkgs.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;
@@ -244,7 +338,9 @@
         zc706-u-boot = u-boot { board = "zc706"; };
         zc706-fsbl = fsbl { board = "zc706"; };
         zc706-bootimage = bootimage { board = "zc706"; };
-        zc706-not-os = not-os-configured.config.system.build.zynq_image;
+        zc706-qemu = not-os-qemu { board = "zc706"; };
+        zc706-sd-image = sd-image { board = "zc706"; };
+        zc706-not-os = not-os-cfg.build.zynq_image;
       };
       hydraJobs = packages.x86_64-linux // packages.armv7l-linux;
     };