diff mbox

[U-Boot,v3,1/3] dts: re-write dts/Makefile more simply with Kbuild

Message ID 1391567307-27434-2-git-send-email-yamada.m@jp.panasonic.com
State Accepted
Delegated to: Tom Rini
Headers show

Commit Message

Masahiro Yamada Feb. 5, 2014, 2:28 a.m. UTC
Useful rules in scripts/Makefile.lib allows us to easily
generate a device tree blob and wrap it in assembly code.

We do not need to parse a linker script to get output format and arch.

This commit deletes ./u-boot.dtb since it is a copy of dts/dt.dtb.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
---

Changes in v3: None
Changes in v2:
  - Rebase on Kbuild series v9
  - Add ';' which was missing in arch/arm/lib/board.c

 .gitignore                  |  1 -
 Makefile                    | 16 +++++-----
 arch/arm/lib/board.c        |  2 +-
 arch/microblaze/lib/board.c |  2 +-
 arch/x86/lib/init_helpers.c |  2 +-
 common/board_f.c            |  2 +-
 dts/.gitignore              |  2 ++
 dts/Makefile                | 72 +++++++++++++--------------------------------
 include/common.h            |  2 +-
 scripts/Makefile.lib        | 12 ++++----
 10 files changed, 41 insertions(+), 72 deletions(-)
 create mode 100644 dts/.gitignore

Comments

Simon Glass Feb. 15, 2014, 11:41 p.m. UTC | #1
Hi,

On 4 February 2014 19:28, Masahiro Yamada <yamada.m@jp.panasonic.com> wrote:
> Useful rules in scripts/Makefile.lib allows us to easily
> generate a device tree blob and wrap it in assembly code.
>
> We do not need to parse a linker script to get output format and arch.
>
> This commit deletes ./u-boot.dtb since it is a copy of dts/dt.dtb.
>
> Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

Sorry I left comments on v2.

Regards,
Simon
Tom Rini Feb. 19, 2014, 9:11 p.m. UTC | #2
On Wed, Feb 05, 2014 at 11:28:25AM +0900, Masahiro Yamada wrote:

> Useful rules in scripts/Makefile.lib allows us to easily
> generate a device tree blob and wrap it in assembly code.
> 
> We do not need to parse a linker script to get output format and arch.
> 
> This commit deletes ./u-boot.dtb since it is a copy of dts/dt.dtb.
> 
> Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

Applied to u-boot/master, thanks!
Masahiro Yamada Feb. 20, 2014, 9:30 a.m. UTC | #3
Hello Tom, Simon,

On Wed, 19 Feb 2014 16:11:11 -0500
Tom Rini <trini@ti.com> wrote:

> On Wed, Feb 05, 2014 at 11:28:25AM +0900, Masahiro Yamada wrote:
> 
> > Useful rules in scripts/Makefile.lib allows us to easily
> > generate a device tree blob and wrap it in assembly code.
> > 
> > We do not need to parse a linker script to get output format and arch.
> > 
> > This commit deletes ./u-boot.dtb since it is a copy of dts/dt.dtb.
> > 
> > Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
> 
> Applied to u-boot/master, thanks!
> 
> -- 
> Tom


Ditto.
Possibly it was missed because Simon and I were discussing
in version 2 thread.


> > >
> > > Besides,  dts/dt.dtb is a prerequisite of dts/dt.dtb.S
> > > when CONFIG_OF_EMBED is enabled.
> > >
> > > I believe keeping dts/dt.dtb is reasonable enough.
> > >
> > > Better to keep both?
> > 
> > Yes I think so.
> 
> 
> OK.
> I will revive ./u-boot.dtb and post a new version.
> 
> And I will send it as a single patch
> dropping 2/3 and 3/3.
> Do you think it's better?
> 
> Many kbuild-related patches are being stuck on patchwork
> and my local branch is getting messed up.
> I don't want to delay this patch any more.


I was planning to post a new version.
But before that, version 3 was applied.

So, what should I do?
Shall I post a follow-up patch to revive a
device tree at the top directory (./u-boot.dtb) ?



Best Regards
Masahiro Yamada
Tom Rini Feb. 20, 2014, 1:39 p.m. UTC | #4
On Thu, Feb 20, 2014 at 06:30:44PM +0900, Masahiro Yamada wrote:
> Hello Tom, Simon,
> 
> On Wed, 19 Feb 2014 16:11:11 -0500
> Tom Rini <trini@ti.com> wrote:
> 
> > On Wed, Feb 05, 2014 at 11:28:25AM +0900, Masahiro Yamada wrote:
> > 
> > > Useful rules in scripts/Makefile.lib allows us to easily
> > > generate a device tree blob and wrap it in assembly code.
> > > 
> > > We do not need to parse a linker script to get output format and arch.
> > > 
> > > This commit deletes ./u-boot.dtb since it is a copy of dts/dt.dtb.
> > > 
> > > Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
> > 
> > Applied to u-boot/master, thanks!
> > 
> > -- 
> > Tom
> 
> 
> Ditto.
> Possibly it was missed because Simon and I were discussing
> in version 2 thread.
> 
> 
> > > >
> > > > Besides,  dts/dt.dtb is a prerequisite of dts/dt.dtb.S
> > > > when CONFIG_OF_EMBED is enabled.
> > > >
> > > > I believe keeping dts/dt.dtb is reasonable enough.
> > > >
> > > > Better to keep both?
> > > 
> > > Yes I think so.
> > 
> > 
> > OK.
> > I will revive ./u-boot.dtb and post a new version.
> > 
> > And I will send it as a single patch
> > dropping 2/3 and 3/3.
> > Do you think it's better?
> > 
> > Many kbuild-related patches are being stuck on patchwork
> > and my local branch is getting messed up.
> > I don't want to delay this patch any more.
> 
> 
> I was planning to post a new version.
> But before that, version 3 was applied.
> 
> So, what should I do?
> Shall I post a follow-up patch to revive a
> device tree at the top directory (./u-boot.dtb) ?

heh, so this is what happens when I try and get ahead of the curve :)
Just do a follow up to bring things into line with what you and Simon
had agreed on.
York Sun May 27, 2014, 6:32 p.m. UTC | #5
On 02/04/2014 06:28 PM, Masahiro Yamada wrote:
> Useful rules in scripts/Makefile.lib allows us to easily
> generate a device tree blob and wrap it in assembly code.
> 
> We do not need to parse a linker script to get output format and arch.
> 
> This commit deletes ./u-boot.dtb since it is a copy of dts/dt.dtb.
> 
> Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
> ---
> 
> Changes in v3: None
> Changes in v2:
>   - Rebase on Kbuild series v9
>   - Add ';' which was missing in arch/arm/lib/board.c
> 

<snip>

>  
> diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
> index b770e25..38b9c7d 100644
> --- a/arch/arm/lib/board.c
> +++ b/arch/arm/lib/board.c
> @@ -280,7 +280,7 @@ void board_init_f(ulong bootflag)
>  	gd->mon_len = _bss_end_ofs;
>  #ifdef CONFIG_OF_EMBED
>  	/* Get a pointer to the FDT */
> -	gd->fdt_blob = _binary_dt_dtb_start;
> +	gd->fdt_blob = __dtb_db_begin;

Is this a typo? I believe it should be __dtb_dt_begin. Did anyone see the
compiling error?

York
Masahiro Yamada May 28, 2014, 12:54 a.m. UTC | #6
Hi York,

> > diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
> > index b770e25..38b9c7d 100644
> > --- a/arch/arm/lib/board.c
> > +++ b/arch/arm/lib/board.c
> > @@ -280,7 +280,7 @@ void board_init_f(ulong bootflag)
> >  	gd->mon_len = _bss_end_ofs;
> >  #ifdef CONFIG_OF_EMBED
> >  	/* Get a pointer to the FDT */
> > -	gd->fdt_blob = _binary_dt_dtb_start;
> > +	gd->fdt_blob = __dtb_db_begin;
> 
> Is this a typo? I believe it should be __dtb_dt_begin. Did anyone see the
> compiling error?


Yes, it's a typo.
I had already posted a patch.
http://patchwork.ozlabs.org/patch/342815/

Even such a simple one has been waiting for more than one month
in Patchwork queue.
:-(

For now, CONFIG_OF_EMBED is defined for MicroBlaze.
I guess nobody saw the compile error.



Best Regards
Masahiro Yamada]
Simon Glass June 1, 2014, 4:34 p.m. UTC | #7
Hi,

On 27 May 2014 18:54, Masahiro Yamada <yamada.m@jp.panasonic.com> wrote:
> Hi York,
>
>> > diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
>> > index b770e25..38b9c7d 100644
>> > --- a/arch/arm/lib/board.c
>> > +++ b/arch/arm/lib/board.c
>> > @@ -280,7 +280,7 @@ void board_init_f(ulong bootflag)
>> >     gd->mon_len = _bss_end_ofs;
>> >  #ifdef CONFIG_OF_EMBED
>> >     /* Get a pointer to the FDT */
>> > -   gd->fdt_blob = _binary_dt_dtb_start;
>> > +   gd->fdt_blob = __dtb_db_begin;
>>
>> Is this a typo? I believe it should be __dtb_dt_begin. Did anyone see the
>> compiling error?
>
>
> Yes, it's a typo.
> I had already posted a patch.
> http://patchwork.ozlabs.org/patch/342815/
>
> Even such a simple one has been waiting for more than one month
> in Patchwork queue.
> :-(
>
> For now, CONFIG_OF_EMBED is defined for MicroBlaze.
> I guess nobody saw the compile error.

I suspect all boards that use CONFIG_OF_CONTROL also use generic board
now. I expect that this file will be deleted at the end of the year.

Regards,
Simon
Michal Simek June 2, 2014, 6:18 a.m. UTC | #8
On 06/01/2014 06:34 PM, Simon Glass wrote:
> Hi,
> 
> On 27 May 2014 18:54, Masahiro Yamada <yamada.m@jp.panasonic.com> wrote:
>> Hi York,
>>
>>>> diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
>>>> index b770e25..38b9c7d 100644
>>>> --- a/arch/arm/lib/board.c
>>>> +++ b/arch/arm/lib/board.c
>>>> @@ -280,7 +280,7 @@ void board_init_f(ulong bootflag)
>>>>     gd->mon_len = _bss_end_ofs;
>>>>  #ifdef CONFIG_OF_EMBED
>>>>     /* Get a pointer to the FDT */
>>>> -   gd->fdt_blob = _binary_dt_dtb_start;
>>>> +   gd->fdt_blob = __dtb_db_begin;
>>>
>>> Is this a typo? I believe it should be __dtb_dt_begin. Did anyone see the
>>> compiling error?
>>
>>
>> Yes, it's a typo.
>> I had already posted a patch.
>> http://patchwork.ozlabs.org/patch/342815/
>>
>> Even such a simple one has been waiting for more than one month
>> in Patchwork queue.
>> :-(
>>
>> For now, CONFIG_OF_EMBED is defined for MicroBlaze.
>> I guess nobody saw the compile error.
> 
> I suspect all boards that use CONFIG_OF_CONTROL also use generic board
> now. I expect that this file will be deleted at the end of the year.

No. Microblaze has no generic board support yet.
For zynq I have sent patches out but they will be merged in the next
merge window.

Thanks,
Michal
diff mbox

Patch

diff --git a/.gitignore b/.gitignore
index 24019b3..5882ff5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -48,7 +48,6 @@ 
 /u-boot.lds
 /u-boot.ubl
 /u-boot.ais
-/u-boot.dtb
 /u-boot.sb
 
 #
diff --git a/Makefile b/Makefile
index cb9c243..b425bfb 100644
--- a/Makefile
+++ b/Makefile
@@ -722,7 +722,7 @@  ALL-$(CONFIG_RAMBOOT_PBL) += u-boot.pbl
 ALL-$(CONFIG_SPL) += spl/u-boot-spl.bin
 ALL-$(CONFIG_SPL_FRAMEWORK) += u-boot.img
 ALL-$(CONFIG_TPL) += tpl/u-boot-tpl.bin
-ALL-$(CONFIG_OF_SEPARATE) += u-boot.dtb u-boot-dtb.bin
+ALL-$(CONFIG_OF_SEPARATE) += u-boot-dtb.bin
 ifneq ($(CONFIG_SPL_TARGET),)
 ALL-$(CONFIG_SPL) += $(CONFIG_SPL_TARGET:"%"=%)
 endif
@@ -746,11 +746,11 @@  endif
 
 all:		$(ALL-y)
 
-u-boot.dtb:	checkdtc u-boot
-		$(MAKE) $(build)=dts binary
-		mv dts/dt.dtb $@
+PHONY += dtbs
+dtbs dts/dt.dtb: checkdtc u-boot
+	$(Q)$(MAKE) $(build)=dts dtbs
 
-u-boot-dtb.bin:	u-boot.bin u-boot.dtb
+u-boot-dtb.bin: u-boot.bin dts/dt.dtb
 		cat $^ >$@
 
 u-boot.hex:	u-boot
@@ -877,8 +877,8 @@  u-boot-nodtb-tegra.bin: spl/u-boot-spl.bin u-boot.bin
 		rm spl/u-boot-spl-pad.bin
 
 ifeq ($(CONFIG_OF_SEPARATE),y)
-u-boot-dtb-tegra.bin: u-boot-nodtb-tegra.bin u-boot.dtb
-		cat u-boot-nodtb-tegra.bin u-boot.dtb > $@
+u-boot-dtb-tegra.bin: u-boot-nodtb-tegra.bin dts/dt.dtb
+		cat $^ > $@
 endif
 endif
 
@@ -1173,7 +1173,7 @@  include/license.h: tools/bin2header COPYING
 # Directories & files removed with 'make clean'
 CLEAN_DIRS  += $(MODVERDIR)
 CLEAN_FILES += u-boot.lds include/bmp_logo.h include/bmp_logo_data.h \
-	       board/*/config.tmp board/*/*/config.tmp dts/*.tmp \
+	       board/*/config.tmp board/*/*/config.tmp \
 	       include/autoconf.mk* include/spl-autoconf.mk \
 	       include/tpl-autoconf.mk
 
diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
index b770e25..38b9c7d 100644
--- a/arch/arm/lib/board.c
+++ b/arch/arm/lib/board.c
@@ -280,7 +280,7 @@  void board_init_f(ulong bootflag)
 	gd->mon_len = _bss_end_ofs;
 #ifdef CONFIG_OF_EMBED
 	/* Get a pointer to the FDT */
-	gd->fdt_blob = _binary_dt_dtb_start;
+	gd->fdt_blob = __dtb_db_begin;
 #elif defined CONFIG_OF_SEPARATE
 	/* FDT is at end of image */
 	gd->fdt_blob = (void *)(_end_ofs + _TEXT_BASE);
diff --git a/arch/microblaze/lib/board.c b/arch/microblaze/lib/board.c
index 59956a8..fafeeae 100644
--- a/arch/microblaze/lib/board.c
+++ b/arch/microblaze/lib/board.c
@@ -87,7 +87,7 @@  void board_init_f(ulong not_used)
 
 #ifdef CONFIG_OF_EMBED
 	/* Get a pointer to the FDT */
-	gd->fdt_blob = _binary_dt_dtb_start;
+	gd->fdt_blob = __dtb_dt_begin;
 #elif defined CONFIG_OF_SEPARATE
 	/* FDT is at end of image */
 	gd->fdt_blob = (void *)__end;
diff --git a/arch/x86/lib/init_helpers.c b/arch/x86/lib/init_helpers.c
index 582c0ff..b5d937f 100644
--- a/arch/x86/lib/init_helpers.c
+++ b/arch/x86/lib/init_helpers.c
@@ -92,7 +92,7 @@  int find_fdt(void)
 {
 #ifdef CONFIG_OF_EMBED
 	/* Get a pointer to the FDT */
-	gd->fdt_blob = _binary_dt_dtb_start;
+	gd->fdt_blob = __dtb_dt_begin;
 #elif defined CONFIG_OF_SEPARATE
 	/* FDT is at end of image */
 	gd->fdt_blob = (ulong *)&_end;
diff --git a/common/board_f.c b/common/board_f.c
index aa70c3e..d0ee6f7 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -360,7 +360,7 @@  static int setup_fdt(void)
 {
 #ifdef CONFIG_OF_EMBED
 	/* Get a pointer to the FDT */
-	gd->fdt_blob = _binary_dt_dtb_start;
+	gd->fdt_blob = __dtb_dt_begin;
 #elif defined CONFIG_OF_SEPARATE
 	/* FDT is at end of image */
 # ifdef CONFIG_SYS_SYM_OFFSETS
diff --git a/dts/.gitignore b/dts/.gitignore
new file mode 100644
index 0000000..1b37180
--- /dev/null
+++ b/dts/.gitignore
@@ -0,0 +1,2 @@ 
+*.dtb
+*.dtb.S
diff --git a/dts/Makefile b/dts/Makefile
index 1e7609a..c47fba7 100644
--- a/dts/Makefile
+++ b/dts/Makefile
@@ -7,64 +7,32 @@ 
 # This Makefile builds the internal U-Boot fdt if CONFIG_OF_CONTROL is
 # enabled. See doc/README.fdt-control for more details.
 
-DTS_INCDIRS =  $(SRCTREE)/board/$(VENDOR)/$(BOARD)/dts
-DTS_INCDIRS += $(SRCTREE)/board/$(VENDOR)/dts
-DTS_INCDIRS += $(SRCTREE)/arch/$(ARCH)/dts
+DEVICE_TREE ?= $(CONFIG_DEFAULT_DEVICE_TREE:"%"=%)
+ifeq ($(DEVICE_TREE),)
+DEVICE_TREE := notfound
+endif
 
-DTS_CPPFLAGS := -x assembler-with-cpp -undef -D__DTS__ \
-		-nostdinc $(addprefix -I,$(DTS_INCDIRS))
+DTS := $(srctree)/board/$(VENDOR)/dts/$(DEVICE_TREE).dts
 
-DTC_FLAGS := -R 4 -p 0x1000 \
-	$(addprefix -i ,$(DTS_INCDIRS))
+DTC_FLAGS += -i $(srctree)/arch/$(ARCH)/dts -R 4 -p 0x1000
 
-# Use a constant name for this so we can access it from C code.
-# objcopy doesn't seem to allow us to set the symbol name independently of
-# the filename.
-DT_BIN	:= $(obj)/dt.dtb
+$(obj)/dt.dtb: $(DTS) FORCE
+	$(call if_changed_dep,dtc)
 
-DEVICE_TREE ?= $(CONFIG_DEFAULT_DEVICE_TREE:"%"=%)
-ifeq ($(DEVICE_TREE),)
-$(DT_BIN): FORCE
-	echo >&2 "Please define CONFIG_DEFAULT_DEVICE_TREE in your board header file"
-else
-$(DT_BIN): $(TOPDIR)/board/$(VENDOR)/dts/$(DEVICE_TREE).dts
-	$(CPP) $(DTS_CPPFLAGS) $< -o $(DT_BIN).dts.tmp
-	$(DTC) $(DTC_FLAGS) -O dtb -o ${DT_BIN} $(DT_BIN).dts.tmp
-endif
+targets += dt.dtb
 
-process_lds = \
-	$(1) | sed -r -n 's/^OUTPUT_$(2)[ ("]*([^")]*).*/\1/p'
+$(DTS):
+	@echo >&2
+	@echo >&2 "Device Tree Source is not specified."
+	@echo >&2 "Please define 'CONFIG_DEFAULT_DEVICE_TREE'"
+	@echo >&2 "or build with 'DEVICE_TREE=<dts-file-name>' argument"
+	@/bin/false
 
-# Run the compiler and get the link script from the linker
-GET_LDS = $(CC) $(c_flags) $(ld_flags) -Wl,--verbose 2>&1
+.SECONDARY: $(obj)/dt.dtb.S
 
-$(obj)/dt.o: $(DT_BIN)
-	# We want the output format and arch.
-	# We also hope to win a prize for ugliest Makefile / shell interaction
-	# We look in the LDSCRIPT first.
-	# Then try the linker which should give us the answer.
-	# Then check it worked.
-	[ -n "$(LDSCRIPT)" ] && \
-		oformat=`$(call process_lds,cat $(LDSCRIPT),FORMAT)` && \
-		oarch=`$(call process_lds,cat $(LDSCRIPT),ARCH)` ;\
-	\
-	[ -z $${oformat} ] && \
-		oformat=`$(call process_lds,$(GET_LDS),FORMAT)` ;\
-	[ -z $${oarch} ] && \
-		oarch=`$(call process_lds,$(GET_LDS),ARCH)` ;\
-	\
-	[ -z $${oformat} ] && \
-		echo "Cannot read OUTPUT_FORMAT from lds file $(LDSCRIPT)" && \
-		exit 1 || true ;\
-	[ -z $${oarch} ] && \
-		echo "Cannot read OUTPUT_ARCH from lds file $(LDSCRIPT)" && \
-		exit 1 || true ;\
-	\
-	cd $(dir ${DT_BIN}) && \
-	$(OBJCOPY) -I binary -O $${oformat} -B $${oarch} \
-		$(notdir ${DT_BIN}) $(notdir $@)
-	rm $(DT_BIN)
+obj-$(CONFIG_OF_EMBED) := dt.dtb.o
 
-obj-$(CONFIG_OF_EMBED)	:= dt.o
+dtbs: $(obj)/dt.dtb
+	@:
 
-binary:	$(DT_BIN)
+clean-files := dt.dtb.S
diff --git a/include/common.h b/include/common.h
index c15e5a4..b590f3a 100644
--- a/include/common.h
+++ b/include/common.h
@@ -302,7 +302,7 @@  int	checkdram     (void);
 int	last_stage_init(void);
 extern ulong monitor_flash_len;
 int mac_read_from_eeprom(void);
-extern u8 _binary_dt_dtb_start[];	/* embedded device tree blob */
+extern u8 __dtb_dt_begin[];	/* embedded device tree blob */
 int set_cpu_clk_info(void);
 int print_cpuinfo(void);
 int update_flash_size(int flash_size);
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index d4b5cb5..ee3ceac 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -151,9 +151,10 @@  cpp_flags      = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(UBOOTINCLUDE)     \
 
 ld_flags       = $(LDFLAGS) $(ldflags-y)
 
+# Modified for U-Boot
 dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \
-		 -I$(srctree)/arch/$(SRCARCH)/boot/dts                   \
-		 -I$(srctree)/arch/$(SRCARCH)/boot/dts/include           \
+		 -I$(srctree)/board/$(VENDOR)/dts/                       \
+		 -I$(srctree)/arch/$(ARCH)/dts                           \
 		 -undef -D__DTS__
 
 # Finds the multi-part object the current object will be linked into
@@ -247,25 +248,24 @@  cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -n -f -9 > $@) || \
 
 # Generate an assembly file to wrap the output of the device tree compiler
 quiet_cmd_dt_S_dtb= DTB     $@
+# Modified for U-Boot
 cmd_dt_S_dtb=						\
 (							\
-	echo '\#include <asm-generic/vmlinux.lds.h>'; 	\
 	echo '.section .dtb.init.rodata,"a"';		\
-	echo '.balign STRUCT_ALIGNMENT';		\
 	echo '.global __dtb_$(*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     $@
+# Modified for U-Boot
 cmd_dtc = $(CPP) $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \
-	$(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 \
+	dtc -O dtb -o $@ -b 0 \
 		-i $(dir $<) $(DTC_FLAGS) \
 		-d $(depfile).dtc.tmp $(dtc-tmp) ; \
 	cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)