[1/4] of: Add support for linking device tree blobs into vmlinux

Commit Message

[e-mail] Dec. 22, 2010, 7:57 p.m. UTC

None

Patch

diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index 0ef00bd..86e3cd0 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -1136,6 +1136,21 @@  When kbuild executes, the following steps are followed (roughly):
 	      resulting in the target file being recompiled for no
 	      obvious reason.
 
+    dtc
+	Create flattend device tree blob object suitable for linking
+	into vmlinux. Device tree blobs linked into vmlinux are placed
+	in an init section in the image. Platform code *must* copy the
+	blob to non-init memory prior to calling unflatten_device_tree().
+
+	Example:
+		#arch/x86/platform/ce4100/Makefile
+		clean-files := *dtb.S
+
+		DTC_FLAGS := -p 1024
+		obj-y += foo.dtb.o
+
+		$(obj)/%.dtb: $(src)/%.dts
+			$(call cmd,dtc)
 
 --- 6.7 Custom kbuild commands
 
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index bd69d79..05cbad0 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -67,7 +67,8 @@ 
  * Align to a 32 byte boundary equal to the
  * alignment gcc 4.5 uses for a struct
  */
-#define STRUCT_ALIGN() . = ALIGN(32)
+#define STRUCT_ALIGNMENT 32
+#define STRUCT_ALIGN() . = ALIGN(STRUCT_ALIGNMENT)
 
 /* The actual configuration determine if the init/exit sections
  * are handled as text/data or they can be discarded (which
@@ -146,6 +147,13 @@ 
 #define TRACE_SYSCALLS()
 #endif
 
+
+#define KERNEL_DTB()							\
+	STRUCT_ALIGN();							\
+	VMLINUX_SYMBOL(__dtb_start) = .;				\
+	*(.dtb.init.rodata)						\
+	VMLINUX_SYMBOL(__dtb_end) = .;
+
 /* .data section */
 #define DATA_DATA							\
 	*(.data)							\
@@ -468,7 +476,8 @@ 
 	MCOUNT_REC()							\
 	DEV_DISCARD(init.rodata)					\
 	CPU_DISCARD(init.rodata)					\
-	MEM_DISCARD(init.rodata)
+	MEM_DISCARD(init.rodata)					\
+	KERNEL_DTB()
 
 #define INIT_TEXT							\
 	*(.init.text)							\
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 4c72c11..7df8eb5 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -200,6 +200,29 @@  quiet_cmd_gzip = GZIP    $@
 cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -f -9 > $@) || \
 	(rm -f $@ ; false)
 
+# DTC
+#  ---------------------------------------------------------------------------
+
+# Generate an assembly file to wrap the output of the device tree compiler
+quiet_cmd_dt_S_dtb= DTB    $@
+cmd_dt_S_dtb=						\
+(							\
+	echo '\#include <asm-generic/vmlinux.lds.h>'; 	\
+	echo '.section .dtb.init.rodata,"a"';		\
+	echo '.balign STRUCT_ALIGNMENT';                \
+	echo '.global __dtb_$(*F)_begin';               \
+	echo '__dtb_$(*F)_begin:';                      \
+	echo '.incbin "$<" ';                           \
+	echo '__dtb_$(*F)_end:';                        \
+	echo '.global __dtb_$(*F)_end';                 \
+	echo '.balign STRUCT_ALIGNMENT'; 		\
+) > $@
+
+$(obj)/%.dtb.S: $(obj)/%.dtb 
+	$(call cmd,dt_S_dtb)
+
+quiet_cmd_dtc = DTC     $@
+      cmd_dtc = $(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 $(DTC_FLAGS) $<
 
 # Bzip2
 # ---------------------------------------------------------------------------