klipper-flash: rewrite flasher script

This completely removes gcc/make from the update loop, and fixes it for
at least some boards.

Although only tested on some boards, and probably lacking support
for some, that's vastly better than sending avr-gcc to your RPi every
update, and not working afterwards.

This also introduces makeFlasher in firmware passthroughs. Use it like
so:
```
  firmware = klipper-firmware.override {
    mcu = "myprinter";
    firmwareConfig = ./config;
  };
  flasher = firmware.makeFlasher {
    flashDevice = "/dev/ttyACM0";
  };
```

pkgs/servers/klipper/klipper-firmware.nix

@@ -1,4 +1,5 @@
-{
+args@{
+  klipper-firmware,
   stdenv,
   lib,
   pkg-config,
@@ -12,9 +13,19 @@
   klipper,
   avrdude,
   stm32flash,
+  klipper-flash,
   mcu ? "mcu",
   firmwareConfig ? ./simulator.cfg,
 }:
+# are used by flash scripts
+# find those with `rg '\[\"lib'` inside of klipper repo
+let
+  flashBinaries = [
+    "lib/bossac/bin/bossac"
+    "lib/hidflash/hid-flash"
+    "lib/rp2040_flash/rp2040_flash"
+  ];
+in
 stdenv.mkDerivation rec {
   name = "klipper-firmware-${mcu}-${version}";
   version = klipper.version;
@@ -38,7 +49,7 @@ stdenv.mkDerivation rec {
     chmod +w ./.config
     echo qy | { make menuconfig >/dev/null || true; }
     if ! diff ${firmwareConfig} ./.config; then
-      echo " !!! Menuconfig has changed. Please update your configuration."
+      echo " !!! Klipper KConfig has changed. Please run klipper-genconf to update your configuration."
     fi
   '';
 
@@ -46,6 +57,11 @@ stdenv.mkDerivation rec {
     patchShebangs .
   '';
 
+  postBuild = ''
+    # build flash binaries
+    ${with builtins; concatStringsSep "\n" (map (path: "make ${path} $out/bin/ || true") flashBinaries)}
+  '';
+
   makeFlags = [
     "V=1"
     "WXVERSION=3.2"
@@ -57,14 +73,47 @@ stdenv.mkDerivation rec {
     cp out/klipper.bin $out/ || true
     cp out/klipper.elf $out/ || true
     cp out/klipper.uf2 $out/ || true
+
+    mkdir -p $out/lib/
+
+    ${
+      with builtins;
+      concatStringsSep "\n" (
+        map (path: ''
+          if [ -e ${path} ]; then
+            mkdir -p $out/$(dirname ${path})
+            cp -r ${path} $out/$(dirname ${path})
+          fi
+        '') flashBinaries
+      )
+    }
+    rmdir $out/lib 2>/dev/null || echo "Flash binaries exist, not cleaning up lib/"
+
   '';
 
   dontFixup = true;
 
+  passthru = {
+    makeFlasher =
+      { flashDevice }:
+      klipper-flash.override {
+        klipper-firmware = klipper-firmware.override args;
+        inherit
+          klipper
+          firmwareConfig
+          mcu
+          flashDevice
+          ;
+      };
+  };
+
   meta = with lib; {
     inherit (klipper.meta) homepage license;
     description = "Firmware part of Klipper";
-    maintainers = with maintainers; [ vtuan10 cab404 ];
+    maintainers = with maintainers; [
+      vtuan10
+      cab404
+    ];
     platforms = platforms.linux;
   };
 }

pkgs/servers/klipper/klipper-flash.nix

@@ -1,47 +1,53 @@
 {
   lib,
   writeShellApplication,
-  gnumake,
-  pkgsCross,
   klipper,
   klipper-firmware,
-  python3,
   avrdude,
+  dfu-util,
   stm32flash,
   mcu ? "mcu",
   flashDevice ? "/dev/null",
   firmwareConfig ? ./simulator.cfg,
 }:
 let
-  supportedArches = [
-    "avr"
-    "stm32"
-    "lpc176x"
-  ];
-  matchBoard =
+  getConfigField =
+    field:
     with builtins;
-    match ''^.*CONFIG_BOARD_DIRECTORY="([a-zA-Z0-9_]+)".*$'' (readFile firmwareConfig);
-  boardArch = if matchBoard == null then null else builtins.head matchBoard;
+    let
+      matches = match ''^.*${field}="([a-zA-Z0-9_]+)".*$'' (readFile firmwareConfig);
+    in
+    if matches != null then head matches else null;
+  matchPlatform = getConfigField "CONFIG_BOARD_DIRECTORY";
+  matchBoard = getConfigField "CONFIG_MCU";
 in
 writeShellApplication {
   name = "klipper-flash-${mcu}";
-  runtimeInputs = [
-    python3
-    pkgsCross.avr.stdenv.cc
-    gnumake
-  ]
-  ++ lib.optionals (boardArch == "avr") [ avrdude ]
-  ++ lib.optionals (boardArch == "stm32") [ stm32flash ];
-  text = ''
-    if ${lib.boolToString (!builtins.elem boardArch supportedArches)}; then
-      printf "Flashing Klipper firmware to your board is not supported yet.\n"
-      printf "Please use the compiled firmware at ${klipper-firmware} and flash it using the tools provided for your microcontroller."
-      exit 1
-    fi
-    if ${lib.boolToString (boardArch == "stm32")}; then
-      make -C ${klipper.src} FLASH_DEVICE="${toString flashDevice}" OUT="${klipper-firmware}/" KCONFIG_CONFIG="${klipper-firmware}/config" serialflash
+  runtimeInputs =
+    [ ]
+    ++ lib.optionals (matchPlatform == "avr") [ avrdude ]
+    ++ lib.optionals (matchPlatform == "stm32") [
+      stm32flash
+      dfu-util
+    ]
+    ++ lib.optionals (matchPlatform == "lpc176x") [ dfu-util ]
+  # bossac, hid-flash and RP2040 flash binaries are built by klipper-firmware
+  ;
+  text =
+    # generic USB script for most things with serial and bootloader (see MCU_TYPES in scripts/flash_usb.py)
+    if matchBoard != null && matchPlatform != null then
+      ''
+        pushd ${klipper-firmware}
+        ${klipper}/lib/scripts/flash_usb.py -t ${matchBoard} -d ${flashDevice} ${klipper-firmware}/klipper.bin $@
+        popd
+      ''
     else
-      make -C ${klipper.src} FLASH_DEVICE="${toString flashDevice}" OUT="${klipper-firmware}/" KCONFIG_CONFIG="${klipper-firmware}/config" flash
-    fi
-  '';
+      ''
+        cat <<EOF
+        Board pair ${toString matchBoard}/${toString matchPlatform} (config ${firmwareConfig}) is not supported in NixOS auto flashing script.
+        Please manually flash the firmware using the appropriate tool for your board.
+        Built firmware is located here:
+        ${klipper-firmware}
+        EOF
+      '';
 }