[U-Boot] [PATCH] Makefile: Only build dtc if needed

[U-Boot] [PATCH] Makefile: Only build dtc if needed

[Simon Glass]

At present U-Boot always builds dtc if CONFIG_OF_CONTROL is defined. This
is wasteful when the system already has a suitable version available.

Update the Makefile logic to build dtc only if the version available is
too old.

This saves about 3 seconds of CPU time on a clean build for me.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

 Makefile               | 17 +++++++++++++++--
 dts/Kconfig            |  4 ----
 scripts/Kbuild.include |  4 +++-
 scripts/Makefile       |  1 -
 scripts/dtc-version.sh | 25 ++++++++++++++++++++-----
 5 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/Makefile b/Makefile
index 250eb6c3c39..fec2b2d8fb5 100644
--- a/Makefile
+++ b/Makefile
@@ -361,7 +361,12 @@ PERL		= perl
 PYTHON		?= python
 PYTHON2		= python2
 PYTHON3		= python3
-DTC		?= $(objtree)/scripts/dtc/dtc
+
+# DTC is automatically built if the version of $(DTC) is older that needed.
+# Use the system dtc if it is new enough.
+DTC		?= dtc
+DTC_MIN_VERSION	:= 010406
+
 CHECK		= sparse
 
 CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
@@ -926,7 +931,7 @@ endif
 PHONY += dtbs
 dtbs: dts/dt.dtb
 	@:
-dts/dt.dtb: u-boot
+dts/dt.dtb: checkdtc u-boot
 	$(Q)$(MAKE) $(build)=dts dtbs
 
 quiet_cmd_copy = COPY    $@
@@ -1579,6 +1584,14 @@ SYSTEM_MAP = \
 System.map:	u-boot
 		@$(call SYSTEM_MAP,$<) > $@
 
+build_dtc	:= $(objtree)/scripts/dtc/dtc
+
+checkdtc:
+	$(eval DTC := $(call dtc-version,010406,$(build_dtc)))
+	if test "$(DTC)" = "$(build_dtc)"; then \
+		$(MAKE) $(build)=scripts/dtc; \
+	fi
+
 #########################################################################
 
 # ARM relocations should all be R_ARM_RELATIVE (32-bit) or
diff --git a/dts/Kconfig b/dts/Kconfig
index 8917f424445..7e600e28f6c 100644
--- a/dts/Kconfig
+++ b/dts/Kconfig
@@ -5,9 +5,6 @@
 config SUPPORT_OF_CONTROL
 	bool
 
-config DTC
-	bool
-
 config PYLIBFDT
 	bool
 
@@ -24,7 +21,6 @@ menu "Device Tree Control"
 
 config OF_CONTROL
 	bool "Run-time configuration via Device Tree"
-	select DTC
 	help
 	  This feature provides for run-time configuration of U-Boot
 	  via a flattened device tree.
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 13ebddda65c..82be40cbe78 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -147,8 +147,10 @@ cc-fullversion = $(shell $(CONFIG_SHELL) \
 cc-ifversion = $(shell [ $(cc-version) $(1) $(2) ] && echo $(3) || echo $(4))
 
 # added for U-Boot
+# $1: min_version
+# #2: build_dtc
 binutils-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/binutils-version.sh $(AS))
-dtc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/dtc-version.sh $(DTC))
+dtc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/dtc-version.sh $(DTC) $1 $2)
 
 # cc-ldoption
 # Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
diff --git a/scripts/Makefile b/scripts/Makefile
index e7b353f77f4..cfe9fef8044 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -10,4 +10,3 @@ always		:= $(hostprogs-y)
 
 # Let clean descend into subdirs
 subdir-	+= basic kconfig
-subdir-$(CONFIG_DTC)	+= dtc
diff --git a/scripts/dtc-version.sh b/scripts/dtc-version.sh
index 0744c39eb04..ec988e18daf 100755
--- a/scripts/dtc-version.sh
+++ b/scripts/dtc-version.sh
@@ -1,12 +1,22 @@
 #!/bin/sh
 #
-# dtc-version dtc-command
+# dtc-version dtc_command min_version build_dtc
 #
-# Prints the dtc version of `dtc-command' in a canonical 6-digit form
-# such as `010404'  for dtc 1.4.4
+# Selects which version of dtc to use
+#
+# If the version of dtc_command is < min_version, prints build_dtc else
+# prints dtc_command. The min_version is in the format MMmmpp where:
+#
+#   MM is the major version
+#   mm is the minor version
+#   pp is the patch level
+#
+# For example 010406 means 1.4.6
 #
 
-dtc="$*"
+dtc="$1"
+min_version="$2"
+build_dtc="$3"
 
 if [ ${#dtc} -eq 0 ]; then
 	echo "Error: No dtc command specified."
@@ -18,4 +28,9 @@ MAJOR=$($dtc -v | head -1 | awk '{print $NF}' | cut -d . -f 1)
 MINOR=$($dtc -v | head -1 | awk '{print $NF}' | cut -d . -f 2)
 PATCH=$($dtc -v | head -1 | awk '{print $NF}' | cut -d . -f 3 | cut -d - -f 1)
 
-printf "%02d%02d%02d\\n" $MAJOR $MINOR $PATCH
+version="$(printf "%02d%02d%02d" $MAJOR $MINOR $PATCH)"
+if test $version -lt $min_version; then \
+	echo $build_dtc
+else
+	echo $dtc
+fi
-- 
2.19.1.930.g4563a0d9d0-goog

[U-Boot] [PATCH] Makefile: Only build dtc if needed

[Marek Vasut]

On 11/13/2018 11:43 PM, Simon Glass wrote:
> At present U-Boot always builds dtc if CONFIG_OF_CONTROL is defined. This
> is wasteful when the system already has a suitable version available.
> 
> Update the Makefile logic to build dtc only if the version available is
> too old.
> 
> This saves about 3 seconds of CPU time on a clean build for me.

Nice !

> Signed-off-by: Simon Glass <sjg@chromium.org>

Reviewed-by: Marek Vasut <marek.vasut@gmail.com>

-- 
Best regards,
Marek Vasut

[U-Boot] [PATCH] Makefile: Only build dtc if needed

[Simon Glass]

Hi Tom,

On Wed, 14 Nov 2018 at 12:51, Marek Vasut <marek.vasut@gmail.com> wrote:
>
> On 11/13/2018 11:43 PM, Simon Glass wrote:
> > At present U-Boot always builds dtc if CONFIG_OF_CONTROL is defined. This
> > is wasteful when the system already has a suitable version available.
> >
> > Update the Makefile logic to build dtc only if the version available is
> > too old.
> >
> > This saves about 3 seconds of CPU time on a clean build for me.
>
> Nice !
>
> > Signed-off-by: Simon Glass <sjg@chromium.org>
>
> Reviewed-by: Marek Vasut <marek.vasut@gmail.com>

Should we pick this one up? It is assigned to you in patchwork.

Regards,
Simon

[U-Boot] Makefile: Only build dtc if needed

[Tom Rini]

On Tue, Nov 13, 2018 at 03:43:07PM -0700, Simon Glass wrote:

> At present U-Boot always builds dtc if CONFIG_OF_CONTROL is defined. This
> is wasteful when the system already has a suitable version available.
> 
> Update the Makefile logic to build dtc only if the version available is
> too old.
> 
> This saves about 3 seconds of CPU time on a clean build for me.
> 
> Signed-off-by: Simon Glass <sjg@chromium.org>
> Reviewed-by: Marek Vasut <marek.vasut@gmail.com>

In the case of new enough host dtc this then fails on sandbox_spl,
chromebook_minnie and others where we need to build
spl/dts/dt-platdata.c with a python import error over lacking _libfdt.

-- 
Tom
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[U-Boot] Makefile: Only build dtc if needed

[Simon Glass]

Hi Tom,

On Sat, 26 Jan 2019 at 20:51, Tom Rini <trini@konsulko.com> wrote:
>
> On Tue, Nov 13, 2018 at 03:43:07PM -0700, Simon Glass wrote:
>
> > At present U-Boot always builds dtc if CONFIG_OF_CONTROL is defined. This
> > is wasteful when the system already has a suitable version available.
> >
> > Update the Makefile logic to build dtc only if the version available is
> > too old.
> >
> > This saves about 3 seconds of CPU time on a clean build for me.
> >
> > Signed-off-by: Simon Glass <sjg@chromium.org>
> > Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
>
> In the case of new enough host dtc this then fails on sandbox_spl,
> chromebook_minnie and others where we need to build
> spl/dts/dt-platdata.c with a python import error over lacking _libfdt.

I'm not sure if it has been long enough, but have the packages been
updated to include pylibfdt?

I'm sending a new version of this patch that checks for that.

Regards,
SImon

[U-Boot] Makefile: Only build dtc if needed

[Tom Rini]

On Sun, Apr 26, 2020 at 06:34:48PM -0600, Simon Glass wrote:
> Hi Tom,
> 
> On Sat, 26 Jan 2019 at 20:51, Tom Rini <trini@konsulko.com> wrote:
> >
> > On Tue, Nov 13, 2018 at 03:43:07PM -0700, Simon Glass wrote:
> >
> > > At present U-Boot always builds dtc if CONFIG_OF_CONTROL is defined. This
> > > is wasteful when the system already has a suitable version available.
> > >
> > > Update the Makefile logic to build dtc only if the version available is
> > > too old.
> > >
> > > This saves about 3 seconds of CPU time on a clean build for me.
> > >
> > > Signed-off-by: Simon Glass <sjg@chromium.org>
> > > Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
> >
> > In the case of new enough host dtc this then fails on sandbox_spl,
> > chromebook_minnie and others where we need to build
> > spl/dts/dt-platdata.c with a python import error over lacking _libfdt.
> 
> I'm not sure if it has been long enough, but have the packages been
> updated to include pylibfdt?
> 
> I'm sending a new version of this patch that checks for that.

I honestly don't know how far behind distributions lag here and then in
turn how old something is before we say "sorry, you can't build there
easily".

-- 
Tom
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[U-Boot] Makefile: Only build dtc if needed

[Simon Glass]

Hi Tom,

On Mon, 27 Apr 2020 at 12:59, Tom Rini <trini@konsulko.com> wrote:
>
> On Sun, Apr 26, 2020 at 06:34:48PM -0600, Simon Glass wrote:
> > Hi Tom,
> >
> > On Sat, 26 Jan 2019 at 20:51, Tom Rini <trini@konsulko.com> wrote:
> > >
> > > On Tue, Nov 13, 2018 at 03:43:07PM -0700, Simon Glass wrote:
> > >
> > > > At present U-Boot always builds dtc if CONFIG_OF_CONTROL is defined. This
> > > > is wasteful when the system already has a suitable version available.
> > > >
> > > > Update the Makefile logic to build dtc only if the version available is
> > > > too old.
> > > >
> > > > This saves about 3 seconds of CPU time on a clean build for me.
> > > >
> > > > Signed-off-by: Simon Glass <sjg@chromium.org>
> > > > Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
> > >
> > > In the case of new enough host dtc this then fails on sandbox_spl,
> > > chromebook_minnie and others where we need to build
> > > spl/dts/dt-platdata.c with a python import error over lacking _libfdt.
> >
> > I'm not sure if it has been long enough, but have the packages been
> > updated to include pylibfdt?
> >
> > I'm sending a new version of this patch that checks for that.
>
> I honestly don't know how far behind distributions lag here and then in
> turn how old something is before we say "sorry, you can't build there
> easily".

I think we should be able to deal with this with respect to dtc at
least, since we can always build it if needed. We just need to get the
conditions right.

Regards,
SImon

[U-Boot] Makefile: Only build dtc if needed

[Tom Rini]

On Mon, Apr 27, 2020 at 04:25:10PM -0600, Simon Glass wrote:
> Hi Tom,
> 
> On Mon, 27 Apr 2020 at 12:59, Tom Rini <trini@konsulko.com> wrote:
> >
> > On Sun, Apr 26, 2020 at 06:34:48PM -0600, Simon Glass wrote:
> > > Hi Tom,
> > >
> > > On Sat, 26 Jan 2019 at 20:51, Tom Rini <trini@konsulko.com> wrote:
> > > >
> > > > On Tue, Nov 13, 2018 at 03:43:07PM -0700, Simon Glass wrote:
> > > >
> > > > > At present U-Boot always builds dtc if CONFIG_OF_CONTROL is defined. This
> > > > > is wasteful when the system already has a suitable version available.
> > > > >
> > > > > Update the Makefile logic to build dtc only if the version available is
> > > > > too old.
> > > > >
> > > > > This saves about 3 seconds of CPU time on a clean build for me.
> > > > >
> > > > > Signed-off-by: Simon Glass <sjg@chromium.org>
> > > > > Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
> > > >
> > > > In the case of new enough host dtc this then fails on sandbox_spl,
> > > > chromebook_minnie and others where we need to build
> > > > spl/dts/dt-platdata.c with a python import error over lacking _libfdt.
> > >
> > > I'm not sure if it has been long enough, but have the packages been
> > > updated to include pylibfdt?
> > >
> > > I'm sending a new version of this patch that checks for that.
> >
> > I honestly don't know how far behind distributions lag here and then in
> > turn how old something is before we say "sorry, you can't build there
> > easily".
> 
> I think we should be able to deal with this with respect to dtc at
> least, since we can always build it if needed. We just need to get the
> conditions right.

To keep the threads in sync, I'm not sure it's worth diverging from the
Linux kernel build in this regard.

-- 
Tom
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