From bb3c82e2a50525eb69fb65c18e87ecd5760908ba Mon Sep 17 00:00:00 2001
From: Bailey Stevens <me@mtxyz.me>
Date: Tue, 4 Apr 2023 13:51:16 -0400
Subject: [PATCH] Adds option for uncompressed image and vm script.

---
 flake.nix   | 33 +++++++++++++++++++++++++--------
 rootfs.nix  |  2 +-
 sd-card.nix | 19 ++++++++++---------
 3 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/flake.nix b/flake.nix
index 71726a5..fa75d49 100644
--- a/flake.nix
+++ b/flake.nix
@@ -11,16 +11,33 @@
   let
     pkgs = import nixpkgs {
       inherit system;
-      crossSystem = nixpkgs.lib.systems.examples.aarch64-multiplatform;
     };
+    crossPkgs = pkgs.pkgsCross.aarch64-multiplatform;
   in
   {
-    packages = let 
-      orange = import ./sd-card.nix { inherit pkgs; };
-    in
-    {
-      default = orange;
+    apps.default = {
+      type = "app";
+      program = "${self.outputs.packages.${system}.vmscript}/bin/vmscript";
     };
-  }
-  );
+    packages = {
+      default = import ./sd-card.nix { inherit pkgs crossPkgs; };
+      uncompressed = import ./sd-card.nix { inherit pkgs crossPkgs; compress = false; };
+
+      vmscript = pkgs.writeScriptBin "vmscript" ''
+      #!${pkgs.runtimeShell}
+      img=${self.outputs.packages.${system}.uncompressed}/sd-card.img
+      ${pkgs.qemu}/bin/qemu-system-aarch64 \
+        -machine raspi3b \
+        -kernel "${crossPkgs.ubootRaspberryPi3_64bit}/u-boot.bin" \
+        -cpu max \
+        -m 1G \
+        -smp 4 \
+        -drive file="$img",format=raw \
+        -serial null \
+        -serial mon:stdio
+      '';
+
+    };
+
+  });
 }
diff --git a/rootfs.nix b/rootfs.nix
index 9ee1adb..7f51672 100644
--- a/rootfs.nix
+++ b/rootfs.nix
@@ -6,7 +6,7 @@ pkgs.stdenv.mkDerivation {
   nativeBuildInputs = with pkgs; [ zstd ];
 
   buildCommand = ''
-    truncate -s 1M ./rootfs.img
+    truncate -s 512M ./rootfs.img
     zstd -T$NIX_BUILD_CORES ./rootfs.img -o $out
   '';
 }
diff --git a/sd-card.nix b/sd-card.nix
index 0a57566..c861f0b 100644
--- a/sd-card.nix
+++ b/sd-card.nix
@@ -1,4 +1,4 @@
-{ pkgs }:
+{ pkgs, crossPkgs, compress ? true}:
 
 let
   firmwarePartition = {
@@ -7,7 +7,6 @@ let
     name = "FIRMWARE";
     size = 512;
   };
-
   rootfsImage = import ./rootfs.nix { inherit pkgs; };
 
   configTxt = pkgs.writeText "config.txt" (builtins.readFile ./config.txt);
@@ -16,12 +15,12 @@ let
     cp ${configTxt} firmware/config.txt
 
     # Copy the firmware files
-    cp ${pkgs.raspberrypifw}/share/raspberrypi/boot/bootcode.bin firmware/
-    cp ${pkgs.raspberrypifw}/share/raspberrypi/boot/fixup*.dat firmware/
-    cp ${pkgs.raspberrypifw}/share/raspberrypi/boot/start*.elf firmware/
+    cp ${crossPkgs.raspberrypifw}/share/raspberrypi/boot/bootcode.bin firmware/
+    cp ${crossPkgs.raspberrypifw}/share/raspberrypi/boot/fixup*.dat firmware/
+    cp ${crossPkgs.raspberrypifw}/share/raspberrypi/boot/start*.elf firmware/
 
     # Add pi3 specific files
-    cp ${pkgs.ubootRaspberryPi3_64bit}/u-boot.bin firmware/u-boot-rpi3.bin
+    cp ${crossPkgs.ubootRaspberryPi3_64bit}/u-boot.bin firmware/u-boot-rpi3.bin
   '';
 in
   pkgs.stdenv.mkDerivation {
@@ -30,7 +29,8 @@ in
     nativeBuildInputs = with pkgs; [ dosfstools e2fsprogs libfaketime mtools util-linux zstd ];
 
     buildCommand = ''
-      img=./sd-card.img
+      mkdir $out
+      img=$out/sd-card.img
       root_fs=./rootfs.img
       zstd -d --no-progress "${rootfsImage}" -o $root_fs
 
@@ -83,7 +83,8 @@ in
 
       dd conv=notrunc if=firmware_part.img of=$img seek=$START count=$SECTORS
 
-      mkdir $out
-      zstd -T$NIX_BUILD_CORES $img -o $out/orange.img.zstd
+      ${pkgs.lib.optionalString compress ''
+      zstd -T$NIX_BUILD_CORES --rm $img
+      ''}
     '';
   }