ARM: Initial dts support

- Add rules to generate dtb files in arch/arm/dts/
- add an initcall which unflattens and probes the internal devicetree
- Add skeleton devicetree

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

7 files changed, 87 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7ac134e159..97af260feb 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -17,6 +17,14 @@ config HAVE_MACH_ARM_HEAD
 
 menu "System Type"
 
+config BUILTIN_DTB
+	bool "link a DTB into the barebox image"
+	depends on OFTREE
+
+config BUILTIN_DTB_NAME
+	string "DTB to build into the barebox image"
+	depends on BUILTIN_DTB
+
 choice
 	prompt "ARM system type"
 
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index b98d6b86a7..6c24b1a0ae 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -254,6 +254,16 @@ zbarebox.S zbarebox.bin zbarebox: barebox.bin
 archclean:
 	$(MAKE) $(clean)=$(pbl)
 
+dts := arch/arm/dts
+
+%.dtb: scripts
+	$(Q)$(MAKE) $(build)=$(dts) $(dts)/$@
+
+dtbs: scripts
+	$(Q)$(MAKE) $(build)=$(dts) dtbs
+
+KBUILD_DTBS := dtbs
+
 KBUILD_IMAGE ?= $(KBUILD_BINARY)
 
 archprepare: maketools
@@ -277,6 +287,8 @@ endif
 common-y += $(BOARD) $(MACH)
 common-y += arch/arm/lib/ arch/arm/cpu/
 
+common-$(CONFIG_BUILTIN_DTB) += arch/arm/dts/
+
 lds-y	:= arch/arm/lib/barebox.lds
 
 CLEAN_FILES += include/generated/mach-types.h arch/arm/lib/barebox.lds barebox-flash-image
diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile
index 44410eec95..525a1806fe 100644
--- a/arch/arm/cpu/Makefile
+++ b/arch/arm/cpu/Makefile
@@ -8,6 +8,7 @@ obj-y += start.o setupc.o
 #
 obj-$(CONFIG_CMD_ARM_CPUINFO) += cpuinfo.o
 obj-$(CONFIG_CMD_ARM_MMUINFO) += mmuinfo.o
+obj-$(CONFIG_BUILTIN_DTB) += dtb.o
 obj-$(CONFIG_MMU) += mmu.o cache.o mmu-early.o
 pbl-$(CONFIG_MMU) += cache.o mmu-early.o
 obj-$(CONFIG_CPU_32v4T) += cache-armv4.o
diff --git a/arch/arm/cpu/dtb.c b/arch/arm/cpu/dtb.c
new file mode 100644
index 0000000000..10b73bd519
--- /dev/null
+++ b/arch/arm/cpu/dtb.c
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2013 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <common.h>
+#include <init.h>
+#include <of.h>
+
+extern char __dtb_start[];
+
+static int of_arm_init(void)
+{
+	struct device_node *root;
+
+	root = of_get_root_node();
+	if (root)
+		return 0;
+
+	root = of_unflatten_dtb(NULL, __dtb_start);
+	if (root) {
+		pr_debug("using internal DTB\n");
+		of_set_root_node(root);
+		if (IS_ENABLED(CONFIG_OFDEVICE))
+			of_probe();
+	}
+
+	return 0;
+}
+core_initcall(of_arm_init);
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
new file mode 100644
index 0000000000..3ee89247e0
--- /dev/null
+++ b/arch/arm/dts/Makefile
@@ -0,0 +1,10 @@
+
+BUILTIN_DTB := $(patsubst "%",%,$(CONFIG_BUILTIN_DTB_NAME)).dtb.o
+obj-$(CONFIG_BUILTIN_DTB) += $(BUILTIN_DTB)
+
+targets += dtbs
+targets += $(dtb-y)
+
+dtbs: $(addprefix $(obj)/, $(dtb-y))
+
+clean-files := *.dtb *.dtb.S
diff --git a/arch/arm/dts/skeleton.dtsi b/arch/arm/dts/skeleton.dtsi
new file mode 100644
index 0000000000..b41d241de2
--- /dev/null
+++ b/arch/arm/dts/skeleton.dtsi
@@ -0,0 +1,13 @@
+/*
+ * Skeleton device tree; the bare minimum needed to boot; just include and
+ * add a compatible value.  The bootloader will typically populate the memory
+ * node.
+ */
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+	chosen { };
+	aliases { };
+	memory { device_type = "memory"; reg = <0 0>; };
+};
diff --git a/arch/arm/lib/barebox.lds.S b/arch/arm/lib/barebox.lds.S
index e5aee8cd82..269f307f73 100644
--- a/arch/arm/lib/barebox.lds.S
+++ b/arch/arm/lib/barebox.lds.S
@@ -88,6 +88,8 @@ SECTIONS
 	__usymtab : { BAREBOX_SYMS }
 	__usymtab_end = .;
 
+	.dtb : { BAREBOX_DTB() }
+
 	_edata = .;
 	. = ALIGN(4);
 	__bss_start = .;