RPi: enable building a device-tree-enabled kernel (branch yem/rpi-dt)

new file mode 100755
index 0000000..f377947
@@ -0,0 +1,227 @@
+#!/usr/bin/env perl
+#
+# Originaly from: https://github.com/raspberrypi/tools/blob/master/mkimage/mkknlimg
+# Original cset : 92a2df13b887f4799554bf92c4fc78d53668c868
+
+use strict;
+use integer;
+
+my $trailer_magic = 'RPTL';
+
+my $tmpfile1 = "/tmp/mkknlimg_$$.1";
+my $tmpfile2 = "/tmp/mkknlimg_$$.2";
+
+my $dtok = 0;
+
+while ($ARGV[0] =~ /^-/)
+{
+    my $arg = shift(@ARGV);
+    if ($arg eq '--dtok')
+    {
+	$dtok = 1;
+    }
+    else
+    {
+	print ("* Unknown option '$arg'\n");
+	usage();
+    }
+}
+
+usage() if (@ARGV != 2);
+
+my $kernel_file = $ARGV[0];
+my $out_file = $ARGV[1];
+
+my @wanted_config_lines =
+(
+	'CONFIG_BCM2708_DT'
+);
+
+my @wanted_strings =
+(
+	'bcm2708_fb',
+	'brcm,bcm2708-pinctrl',
+	'brcm,bcm2835-gpio',
+	'of_find_property'
+);
+
+my $res = try_extract($kernel_file, $tmpfile1);
+
+$res = try_decompress('\037\213\010', 'xy',    'gunzip', 0,
+		      $kernel_file, $tmpfile1, $tmpfile2) if (!$res);
+$res = try_decompress('\3757zXZ\000', 'abcde', 'unxz --single-stream', -1,
+		      $kernel_file, $tmpfile1, $tmpfile2) if (!$res);
+$res = try_decompress('BZh',          'xy',    'bunzip2', 0,
+		      $kernel_file, $tmpfile1, $tmpfile2) if (!$res);
+$res = try_decompress('\135\0\0\0',   'xxx',   'unlzma', 0,
+		      $kernel_file, $tmpfile1, $tmpfile2) if (!$res);
+$res = try_decompress('\211\114\132', 'xy',    'lzop -d', 0,
+		      $kernel_file, $tmpfile1, $tmpfile2) if (!$res);
+
+my $append_trailer;
+my $trailer;
+
+if ($res)
+{
+    print("Version: $res->{''}\n");
+
+    $append_trailer = $dtok;
+    if (!$dtok)
+    {
+	if (config_bool($res, 'bcm2708_fb'))
+	{
+	    $dtok ||= config_bool($res, 'CONFIG_BCM2708_DT');
+	    $dtok ||= config_bool($res, 'brcm,bcm2708-pinctrl');
+	    $dtok ||= config_bool($res, 'brcm,bcm2835-gpio');
+	    $append_trailer = 1;
+	}
+	else
+	{
+	    print ("* This doesn't look like a Raspberry Pi kernel. In pass-through mode.\n");
+	}
+    }
+}
+else
+{
+    print ("* Is this a valid kernel? In pass-through mode.\n");
+}
+
+if ($append_trailer)
+{
+    printf("DT: %s\n", $dtok ? "y" : "n");
+
+    my @atoms;
+
+    push @atoms, [ $trailer_magic, pack('V', 0) ];
+    push @atoms, [ 'KVer', $res->{''} ];
+    push @atoms, [ 'DTOK', pack('V', $dtok) ];
+
+    $trailer = pack_trailer(\@atoms);
+    $atoms[0]->[1] = pack('V', length($trailer));
+
+    $trailer = pack_trailer(\@atoms);
+}
+
+die "* Failed to open '$kernel_file'\n" if (!open(my $ifh, '<', $kernel_file));
+die "* Failed to create '$out_file'\n" if (!open(my $ofh, '>', $out_file));
+
+my $copybuf;
+my $total_len = 0;
+while (1)
+{
+	my $bytes = sysread($ifh, $copybuf, 64*1024);
+	last if (!$bytes);
+	syswrite($ofh, $copybuf, $bytes);
+	$total_len += $bytes;
+}
+
+if ($trailer)
+{
+    # Pad to word-alignment
+    syswrite($ofh, "\x000\x000\x000", (-$total_len & 0x3));
+    syswrite($ofh, $trailer);
+}
+
+close($ifh);
+close($ofh);
+
+exit($trailer ? 0 : 1);
+
+END {
+	unlink($tmpfile1) if ($tmpfile1);
+	unlink($tmpfile2) if ($tmpfile2);
+}
+
+
+sub usage
+{
+	print ("Usage: mkknlimg [--dtok] <vmlinux|zImage|bzImage> <outfile>\n");
+	exit(1);
+}
+
+sub try_extract
+{
+	my ($knl, $tmp) = @_;
+
+	my $ver = `strings "$knl" | grep -a -E "^Linux version [1-9]"`;
+
+	return undef if (!$ver);
+
+	chomp($ver);
+
+	my $res = { ''=>$ver };
+	my $string_pattern = '^('.join('|', @wanted_strings).')$';
+
+	my @matches = `strings \"$knl\" | grep -E \"$string_pattern\"`;
+	foreach my $match (@matches)
+	{
+	    chomp($match);
+	    $res->{$match} = 1;
+	}
+
+	my $config_pattern = '^('.join('|', @wanted_config_lines).')=(.*)$';
+	my $cf1 = 'IKCFG_ST\037\213\010';
+	my $cf2 = '0123456789';
+
+	my $pos = `tr "$cf1\n$cf2" "\n$cf2=" < "$knl" | grep -abo "^$cf2"`;
+	if ($pos)
+	{
+		$pos =~ s/:.*[\r\n]*$//s;
+		$pos += 8;
+		my $err = (system("tail -c+$pos \"$knl\" | zcat > $tmp 2> /dev/null") >> 8);
+		if (($err == 0) || ($err == 2))
+		{
+			if (open(my $fh, '<', $tmp))
+			{
+				while (my $line = <$fh>)
+				{
+					chomp($line);
+					$res->{$1} = $2 if ($line =~ /$config_pattern/);
+				}
+
+				close($fh);
+			}
+		}
+	}
+
+	return $res;
+}
+
+
+sub try_decompress
+{
+	my ($magic, $subst, $zcat, $idx, $knl, $tmp1, $tmp2) = @_;
+
+	my $pos = `tr "$magic\n$subst" "\n$subst=" < "$knl" | grep -abo "^$subst"`;
+	if ($pos)
+	{
+		chomp($pos);
+		$pos = (split(/[\r\n]+/, $pos))[$idx];
+		$pos =~ s/:.*[\r\n]*$//s;
+		my $cmd = "tail -c+$pos \"$knl\" | $zcat > $tmp2 2> /dev/null";
+		my $err = (system($cmd) >> 8);
+		return undef if (($err != 0) && ($err != 2));
+
+		return try_extract($tmp2, $tmp1);
+	}
+
+	return undef;
+}
+
+sub pack_trailer
+{
+	my ($atoms) = @_;
+	my $trailer = pack('VV', 0, 0);
+	for (my $i = $#$atoms; $i>=0; $i--)
+	{
+		my $atom = $atoms->[$i];
+		$trailer .= pack('a*x!4Va4', $atom->[1], length($atom->[1]), $atom->[0]);
+	}
+	return $trailer;
+}
+
+sub config_bool
+{
+	my ($configs, $wanted) = @_;
+	return (($configs->{$wanted} eq 'y') || ($configs->{$wanted} eq '1'));
+}

index 571a546..eb835ee 100644
@@ -19,4 +19,14 @@ define RPI_FIRMWARE_INSTALL_IMAGES_CMDS
 	$(INSTALL) -D -m 0644 package/rpi-firmware/cmdline.txt $(BINARIES_DIR)/rpi-firmware/cmdline.txt
 endef
 
+# We have no host sources to get, since we already
+# bundle the script we want to install.
+HOST_RPI_FIRMWARE_SOURCE =
+HOST_RPI_FIRMWARE_DEPENDENCIES =
+
+define HOST_RPI_FIRMWARE_INSTALL_CMDS
+	$(INSTALL) -D -m 0755 package/rpi-firmware/mkknlimg $(HOST_DIR)/usr/bin/mkknlimg
+endef
+
 $(eval $(generic-package))
+$(eval $(host-generic-package))

index cd45be4..80ba88a 100644
@@ -45,4 +45,15 @@ config BR2_PACKAGE_RPI_FIRMWARE_BOOT
 	default "_x"    if BR2_PACKAGE_RPI_FIRMWARE_X
 	default "_cd"   if BR2_PACKAGE_RPI_FIRMWARE_CD
 
+config BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTBS
+	bool "Install Device Tree Blobs (DTBs)"
+	help
+	  Say 'y' here if you want to boot your kernel that has support
+	  for the device tree.
+
+	  Note that the defconfig files in the Raspberry Pi fork of the
+	  Linux kernel do not enable support for the Device Tree. You'll
+	  have to provide your own Linux config or defconfig file with
+	  device tree enabled, to make use of those DTBs.
+
 endif # BR2_PACKAGE_RPI_FIRMWARE

index eb835ee..04c6160 100644
@@ -11,12 +11,26 @@ RPI_FIRMWARE_LICENSE_FILES = boot/LICENCE.broadcom
 RPI_FIRMWARE_INSTALL_TARGET = NO
 RPI_FIRMWARE_INSTALL_IMAGES = YES
 
+ifeq ($(BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTBS),y)
+RPI_FIRMWARE_DEPENDENCIES += host-rpi-firmware
+# Override the version in this case.
+RPI_FIRMWARE_VERSION = 09627457b9e15bf4ea4e6751d3c173a3fb65df07
+define RPI_FIRMWARE_INSTALL_DTB
+	$(INSTALL) -D -m 0644 $(@D)/boot/bcm2708-rpi-b.dtb $(BINARIES_DIR)/rpi-firmware/bcm2708-rpi-b.dtb
+	$(INSTALL) -D -m 0644 $(@D)/boot/bcm2708-rpi-b-plus.dtb $(BINARIES_DIR)/rpi-firmware/bcm2708-rpi-b-plus.dtb
+	for ovldtb in  $(@D)/boot/overlays/*.dtb; do \
+		$(INSTALL) -D -m 0644 $${ovldtb} $(BINARIES_DIR)/rpi-firmware/overlays/$${ovldtb##*/} || exit 1; \
+	done
+endef
+endif
+
 define RPI_FIRMWARE_INSTALL_IMAGES_CMDS
 	$(INSTALL) -D -m 0644 $(@D)/boot/bootcode.bin $(BINARIES_DIR)/rpi-firmware/bootcode.bin
 	$(INSTALL) -D -m 0644 $(@D)/boot/start$(BR2_PACKAGE_RPI_FIRMWARE_BOOT).elf $(BINARIES_DIR)/rpi-firmware/start.elf
 	$(INSTALL) -D -m 0644 $(@D)/boot/fixup$(BR2_PACKAGE_RPI_FIRMWARE_BOOT).dat $(BINARIES_DIR)/rpi-firmware/fixup.dat
 	$(INSTALL) -D -m 0644 package/rpi-firmware/config.txt $(BINARIES_DIR)/rpi-firmware/config.txt
 	$(INSTALL) -D -m 0644 package/rpi-firmware/cmdline.txt $(BINARIES_DIR)/rpi-firmware/cmdline.txt
+	$(RPI_FIRMWARE_INSTALL_DTB)
 endef
 
 # We have no host sources to get, since we already

index 8532de4..a6d3dd4 100644
@@ -55,9 +55,7 @@ After building, you should obtain this tree:
     +-- rpi-firmware
     |   +-- bootcode.bin
     |   +-- config.txt
-    |   +-- fixup_cd.dat
     |   +-- fixup.dat
-    |   +-- start_cd.elf
     |   `-- start.elf
     `-- zImage
 

index a6d3dd4..725ad9d 100644
@@ -23,6 +23,10 @@ work on this defconfig:
 
   $ make raspberrypi_defconfig
 
+Alternatively, if you want to test support for the Device Tree:
+
+  $ make raspberrypi_dt_defconfig
+
 If you want to use a persistent rootfs, skip to "Build the rootfs", below.
 
 For a volatile rootfs, you have to slightly adjust the configuration:

@@ -51,16 +55,22 @@ Result of the build
 After building, you should obtain this tree:
 
     output/images/
-    +-- rootfs.tar
-    +-- rpi-firmware
+    +-- rootfs.tar                              [0]
+    +-- rpi-firmware/
+    |   +-- bcm2708-rpi-b.dtb                   [1]
+    |   +-- bcm2708-rpi-b-plus.dtb              [1]
     |   +-- bootcode.bin
     |   +-- config.txt
     |   +-- fixup.dat
     |   `-- start.elf
     `-- zImage
 
-Note for Volatile: rootfs.tar will only be there if you kept
-"tar the root filesystem" option selected in "Filesystem images".
+[0] Note for Volatile: rootfs.tar will only be there if you kept
+    "tar the root filesystem" option selected in "Filesystem images".
+
+[1] The DTBs (Device Tree Blobs) will only be present if you setup
+    Buildroot to install the DTBs from the rpi-firmware package, and
+    will only be used if your kernel has support for the Device Tree.
 
 Prepare you SDCard
 ==================

@@ -89,17 +99,30 @@ Install the binaries to the SDCard
 At the root of the boot partition, the RaspberryPi must find the following
 files:
 
+    * bcm2708-rpi-b.dtb         [2]
+    * bcm2708-rpi-b-plus.dtb    [2]
     * bootcode.bin
     * config.txt
     * fixup.dat
     * start.elf
     * zImage
 
+[2] Only needed if your kernel has support for the Device Tree.
+
 For example:
 
  $ cp output/images/rpi-firmware/* /mnt/mountpointboot
+
+If your kernel does *not* have support for the Device Tree, then install
+it with:
+
  $ cp output/images/zImage /mnt/mountpointboot
 
+If your kernel *does* have support for the Device Tree, then install it
+with:
+
+  $ ./output/host/usr/bin/mkknlimg output/images/zImage /mnt/mountpointboot/zImage
+
 Note: The kernel image file name is defined in config.txt like this:
 kernel=zImage
 

new file mode 100644
index 0000000..188ece9
@@ -0,0 +1,12 @@
+BR2_arm=y
+BR2_arm1176jzf_s=y
+BR2_TOOLCHAIN_EXTERNAL=y
+BR2_TARGET_GENERIC_GETTY_PORT="tty1"
+BR2_LINUX_KERNEL=y
+BR2_LINUX_KERNEL_CUSTOM_GIT=y
+BR2_LINUX_KERNEL_CUSTOM_REPO_URL="git://github.com/raspberrypi/linux.git"
+BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="b9c9f8fc69aaba236169798c18dc1590fccf7acd"
+BR2_LINUX_KERNEL_DEFCONFIG="bcmrpi"
+BR2_LINUX_KERNEL_ZIMAGE=y
+BR2_PACKAGE_RPI_FIRMWARE=y
+BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTBS=y