Merge branch 'raspberrypi'

Adding support for the kind of bootloader in raspberrypi. Disable grub,
disable generationsDir, enable boot.loader.raspberrypi.

Usual layout expected: /boot being the first vfat the board reads blobs from.

modules/module-list.nix

@@ -200,6 +200,7 @@
   ./system/boot/kernel.nix
   ./system/boot/loader/efi-boot-stub/efi-boot-stub.nix
   ./system/boot/loader/generations-dir/generations-dir.nix
+  ./system/boot/loader/raspberrypi/raspberrypi.nix
   ./system/boot/loader/grub/grub.nix
   ./system/boot/loader/grub/memtest.nix
   ./system/boot/loader/init-script/init-script.nix

modules/system/boot/loader/raspberrypi/builder.sh

@@ -0,0 +1,109 @@
+#! @bash@/bin/sh -e
+
+shopt -s nullglob
+
+export PATH=/empty
+for i in @path@; do PATH=$PATH:$i/bin; done
+
+default=$1
+if test -z "$1"; then
+    echo "Syntax: builder.sh <DEFAULT-CONFIG>"
+    exit 1
+fi
+
+echo "updating the boot generations directory..."
+
+mkdir -p /boot/old
+
+# Convert a path to a file in the Nix store such as
+# /nix/store/<hash>-<name>/file to <hash>-<name>-<file>.
+cleanName() {
+    local path="$1"
+    echo "$path" | sed 's|^/nix/store/||' | sed 's|/|-|g'
+}
+
+# Copy a file from the Nix store to /boot/kernels.
+declare -A filesCopied
+
+copyToKernelsDir() {
+    local src="$1"
+    local dst="/boot/old/$(cleanName $src)"
+    # Don't copy the file if $dst already exists.  This means that we
+    # have to create $dst atomically to prevent partially copied
+    # kernels or initrd if this script is ever interrupted.
+    if ! test -e $dst; then
+        local dstTmp=$dst.tmp.$$
+        cp $src $dstTmp
+        mv $dstTmp $dst
+    fi
+    filesCopied[$dst]=1
+    result=$dst
+}
+
+copyForced() {
+    local src="$1"
+    local dst="$2"
+    cp $src $dst.tmp
+    mv $dst.tmp $dst
+}
+
+outdir=/boot/old
+mkdir -p $outdir || true
+
+# Copy its kernel and initrd to /boot/kernels.
+addEntry() {
+    local path="$1"
+    local generation="$2"
+
+    if ! test -e $path/kernel -a -e $path/initrd; then
+        return
+    fi
+
+    local kernel=$(readlink -f $path/kernel)
+    # local initrd=$(readlink -f $path/initrd)
+
+    if test -n "@copyKernels@"; then
+        copyToKernelsDir $kernel; kernel=$result
+        # copyToKernelsDir $initrd; initrd=$result
+    fi
+    
+    echo $(readlink -f $path) > $outdir/$generation-system
+    echo $(readlink -f $path/init) > $outdir/$generation-init
+    cp $path/kernel-params $outdir/$generation-cmdline.txt
+    # echo $initrd > $outdir/$generation-initrd
+    echo $kernel > $outdir/$generation-kernel
+
+    if test $(readlink -f "$path") = "$default"; then
+      copyForced $kernel /boot/kernel.img
+      # copyForced $initrd /boot/initrd
+      cp "$(readlink -f "$path/init")" /boot/nixos-init
+      echo "`cat $path/kernel-params` init=$path/init" >/boot/cmdline.txt
+
+      echo "$2" > /boot/defaultgeneration
+    fi
+}
+
+# Add all generations of the system profile to the menu, in reverse
+# (most recent to least recent) order.
+for generation in $(
+    (cd /nix/var/nix/profiles && ls -d system-*-link) \
+    | sed 's/system-\([0-9]\+\)-link/\1/' \
+    | sort -n -r); do
+    link=/nix/var/nix/profiles/system-$generation-link
+    addEntry $link $generation
+done
+
+# Add the firmware files
+fwdir=@firmware@/share/raspberrypi/boot/
+copyForced $fwdir/bootcode.bin  /boot/bootcode.bin
+copyForced $fwdir/fixup.dat     /boot/fixup.dat
+copyForced $fwdir/fixup_cd.dat  /boot/fixup_cd.dat
+copyForced $fwdir/start.elf     /boot/start.elf
+copyForced $fwdir/start_cd.elf  /boot/start_cd.elf
+
+# Remove obsolete files from /boot/old.
+for fn in /boot/old/*linux* /boot/old/*initrd*; do
+    if ! test "${filesCopied[$fn]}" = 1; then
+        rm -vf -- "$fn"
+    fi
+done

modules/system/boot/loader/raspberrypi/raspberrypi.nix

@@ -0,0 +1,51 @@
+{pkgs, config, ...}:
+
+###### interface
+let
+  inherit (pkgs.lib) mkOption mkIf;
+
+  options = {
+    boot = {
+      loader = {
+        raspberryPi = {
+          enable = mkOption {
+            default = false;
+            description = ''
+              Whether to create files with the system generations in
+              <literal>/boot</literal>. 
+              <literal>/boot/old</literal> will hold files from old generations.
+            '';
+          };
+        };
+      };
+    };
+  };
+
+in
+
+###### implementation
+let
+  builder = pkgs.substituteAll {
+    src = ./builder.sh;
+    isExecutable = true;
+    inherit (pkgs) bash;
+    path = [pkgs.coreutils pkgs.gnused pkgs.gnugrep];
+    firmware = pkgs.raspberrypifw;
+  };
+
+  platform = pkgs.stdenv.platform;
+in
+{
+  require = [
+    options
+
+    # config.system.build
+    # ../system/system-options.nix
+  ];
+
+  system = mkIf config.boot.loader.raspberryPi.enable {
+    build.installBootLoader = builder;
+    boot.loader.id = "raspberrypi";
+    boot.loader.kernelFile = platform.kernelTarget;
+  };
+}