[50/52] package/dtc: new package

dtc is the Device Tree Compiler, and manipulates device trees.

Cc: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

---
Although Arnout suggested to move it out of the libraries sub-menu,
I kept it there, as by default, only the library is installed, like
it is done for, eg., libcurl.
---
 package/Config.in                          |    1 +
 package/dtc/Config.in                      |    9 +++++++
 package/dtc/dtc-extra_cflags.patch         |   27 ++++++++++++++++++++++
 package/dtc/dtc-separate-lib-install.patch |   28 +++++++++++++++++++++++
 package/dtc/dtc.mk                         |   34 ++++++++++++++++++++++++++++
 5 files changed, 99 insertions(+), 0 deletions(-)
 create mode 100644 package/dtc/Config.in
 create mode 100644 package/dtc/dtc-extra_cflags.patch
 create mode 100644 package/dtc/dtc-separate-lib-install.patch
 create mode 100644 package/dtc/dtc.mk

Hi Yann,

On Tue, Dec 11, 2012 at 12:45 AM, Yann E. MORIN <yann.morin.1998@free.fr> wrote:
> dtc is the Device Tree Compiler, and manipulates device trees.
>
> Cc: Arnout Vandecappelle <arnout@mind.be>
> Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
>
> ---
> Although Arnout suggested to move it out of the libraries sub-menu,
> I kept it there, as by default, only the library is installed, like
> it is done for, eg., libcurl.
> ---
>  package/Config.in                          |    1 +
>  package/dtc/Config.in                      |    9 +++++++
>  package/dtc/dtc-extra_cflags.patch         |   27 ++++++++++++++++++++++
>  package/dtc/dtc-separate-lib-install.patch |   28 +++++++++++++++++++++++
>  package/dtc/dtc.mk                         |   34 ++++++++++++++++++++++++++++
>  5 files changed, 99 insertions(+), 0 deletions(-)
>  create mode 100644 package/dtc/Config.in
>  create mode 100644 package/dtc/dtc-extra_cflags.patch
>  create mode 100644 package/dtc/dtc-separate-lib-install.patch
>  create mode 100644 package/dtc/dtc.mk
>
> diff --git a/package/Config.in b/package/Config.in
> index a93aed2..ef7f44d 100644
> --- a/package/Config.in
> +++ b/package/Config.in
> @@ -417,6 +417,7 @@ endmenu
>
>  menu "Hardware handling"
>  source "package/ccid/Config.in"
> +source "package/dtc/Config.in"
>  source "package/lcdapi/Config.in"
>  source "package/libaio/Config.in"
>  source "package/libraw1394/Config.in"
> diff --git a/package/dtc/Config.in b/package/dtc/Config.in
> new file mode 100644
> index 0000000..96225e3
> --- /dev/null
> +++ b/package/dtc/Config.in
> @@ -0,0 +1,9 @@
> +config BR2_PACKAGE_DTC
> +       bool "dtc"
> +       help
> +         The Device Tree Compiler, dtc, takes as input a device-tree in
> +         a given format and outputs a device-tree in another format.
> +
> +         Note that only the library is installed for now.
> +
> +         http://git.jdl.com/gitweb/?p=dtc.git  (no home page)
> diff --git a/package/dtc/dtc-extra_cflags.patch b/package/dtc/dtc-extra_cflags.patch
> new file mode 100644
> index 0000000..9d1882b
> --- /dev/null
> +++ b/package/dtc/dtc-extra_cflags.patch
> @@ -0,0 +1,27 @@
> +Makefile: append the CFLAGS to existing ones
> +
> +Allow the user to pass custom CFLAGS (eg. optimisation flags).
> +
> +Do not use EXTRA_CFLAGS, append to existing CFLAGS with +=  (Arnout)
> +
> +Cc: Arnout Vandecappelle <arnout@mind.be>
> +Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> +
> +---
> +Patch not sent upstream.
> +
> +Although not specific to buildroot, I am not sure this is the best
> +way to handle user-supplied CFLAGS.
> +
> +diff -durN dtc-e4b497f367a3b2ae99cc52089a14a221b13a76ef.orig/Makefile dtc-e4b497f367a3b2ae99cc52089a14a221b13a76ef/Makefile
> +--- dtc-e4b497f367a3b2ae99cc52089a14a221b13a76ef.orig/Makefile 2012-10-22 22:02:47.541240846 +0200
> ++++ dtc-e4b497f367a3b2ae99cc52089a14a221b13a76ef/Makefile      2012-10-22 22:03:21.151047833 +0200
> +@@ -18,7 +18,7 @@
> + CPPFLAGS = -I libfdt -I .
> + WARNINGS = -Werror -Wall -Wpointer-arith -Wcast-qual -Wnested-externs \
> +       -Wstrict-prototypes -Wmissing-prototypes -Wredundant-decls
> +-CFLAGS = -g -Os -fPIC -Werror $(WARNINGS)
> ++CFLAGS += -g -Os -fPIC -Werror $(WARNINGS)
> +
> + BISON = bison
> + LEX = flex
> diff --git a/package/dtc/dtc-separate-lib-install.patch b/package/dtc/dtc-separate-lib-install.patch
> new file mode 100644
> index 0000000..c86d587
> --- /dev/null
> +++ b/package/dtc/dtc-separate-lib-install.patch
> @@ -0,0 +1,28 @@
> +Makefile: add a rule to only install libfdt
> +
> +Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> +
> +---
> +Patch not sent upstream.
> +
> +It's really specific to buildroot, and is probably not
> +good (aka generic) enough to be pushed upstream.
> +
> +diff --git a/Makefile b/Makefile
> +index 1169e6c..39e7190 100644
> +--- a/Makefile
> ++++ b/Makefile
> +@@ -160,10 +160,12 @@ endif
> + # intermediate target and building them again "for real"
> + .SECONDARY: $(DTC_GEN_SRCS) $(CONVERT_GEN_SRCS)
> +
> +-install: all $(SCRIPTS)
> ++install: all $(SCRIPTS) libfdt_install
> +       @$(VECHO) INSTALL
> +       $(INSTALL) -d $(DESTDIR)$(BINDIR)
> +       $(INSTALL) $(BIN) $(SCRIPTS) $(DESTDIR)$(BINDIR)
> ++
> ++libfdt_install: libfdt
> +       $(INSTALL) -d $(DESTDIR)$(LIBDIR)
> +       $(INSTALL) $(LIBFDT_lib) $(DESTDIR)$(LIBDIR)
> +       ln -sf $(notdir $(LIBFDT_lib)) $(DESTDIR)$(LIBDIR)/$(LIBFDT_soname)
> diff --git a/package/dtc/dtc.mk b/package/dtc/dtc.mk
> new file mode 100644
> index 0000000..a0e1e35
> --- /dev/null
> +++ b/package/dtc/dtc.mk
> @@ -0,0 +1,34 @@
> +#############################################################
> +#
> +# dtc
> +#
> +#############################################################
> +
> +DTC_VERSION         = e4b497f367a3b2ae99cc52089a14a221b13a76ef
> +DTC_SITE            = git://git.jdl.com/software/dtc.git
> +DTC_LICENSE         = GPLv2+/BSD-2c
> +DTC_LICENSE_FILES   = README.license GPL
> +# Note: the dual-license only applies to the library.
> +#       The DT compiler (dtc) is GPLv2+, but we do not install it.
> +DTC_INSTALL_STAGING = YES
> +
> +define DTC_BUILD_CMDS
> +       $(TARGET_CONFIGURE_OPTS)    \
> +       CFLAGS="$(TARGET_CFLAGS)"   \
> +       $(MAKE) -C $(@D) PREFIX=/usr libfdt
> +endef
> +
> +# libfdt_install is our own install rule added by our patch
> +define DTC_INSTALL_STAGING_CMDS
> +       $(MAKE) -C $(@D) DESTDIR=$(STAGING_DIR) PREFIX=/usr libfdt_install
> +endef
> +
> +define DTC_INSTALL_TARGET_CMDS
> +       $(MAKE) -C $(@D) DESTDIR=$(TARGET_DIR) PREFIX=/usr libfdt_install
> +endef
> +
> +define DTC_CLEAN_CMDS
> +       $(MAKE) -C $(@D) libfdt_clean
> +endef
> +
> +$(eval $(generic-package))
> --
> 1.7.2.5

Are you aware of the following code in linux/linux.mk ?

define LINUX_INSTALL_HOST_TOOLS
# Installing dtc (device tree compiler) as host tool, if selected
if grep -q "CONFIG_DTC=y" $(@D)/.config; then \
$(INSTALL) -D -m 0755 $(@D)/scripts/dtc/dtc $(HOST_DIR)/usr/bin/dtc ; \
fi
endef

In this case, the dtc shipped with the linux kernel is simply used.
This was considered to be sufficient for most cases.

If this is not true and there really is a need for the separate dtc
package, I think we should link both together in some way, either by a
comment, or by a mutually exclusive configuration, or ...

Best regards,
Thomas

Thomas, All,

On Tuesday 11 December 2012 13:38:03 Thomas De Schampheleire wrote:
> On Tue, Dec 11, 2012 at 12:45 AM, Yann E. MORIN <yann.morin.1998@free.fr> wrote:
> > dtc is the Device Tree Compiler, and manipulates device trees.
> >
> > Cc: Arnout Vandecappelle <arnout@mind.be>
> > Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

> Are you aware of the following code in linux/linux.mk ?
> 
> define LINUX_INSTALL_HOST_TOOLS
> # Installing dtc (device tree compiler) as host tool, if selected
> if grep -q "CONFIG_DTC=y" $(@D)/.config; then \
> $(INSTALL) -D -m 0755 $(@D)/scripts/dtc/dtc $(HOST_DIR)/usr/bin/dtc ; \
> fi
> endef

I was vaguely aware of it, yes, although I did not look at it, for a
few reasons:

  - the DTC in the kernel is not at par with the DTC in the package
    (they diverge a bit, and the DTC in the kernel was recently
    resynce, cset #cd29672).

  - for QEMU, I really needed the libfdt library, not the tools; but
    the dtc in the Linux kernel does not build the libfdt library.

  - as Arnout suggested adding the tools on the target too, I deemed
    preferable to use the tools coming with the library rather than
    risk ABI incompatibility between the ones from dtc and the .ones
    from the kernel

  - the one from the kernel is a host tool, used to build the kernel
    itself, while the ones from dtc are target tools, that are supposed
    to be used to build DTCs for use by QEMU. Thus they serve two
    different purposes, and there is no strong requirement that they
    be compatible.

It's also a reason why I did not add $(eval $(host-generic-package))
in the dtc package.

And a fifth reason (the most important one, to me!):
  - I have had a patch accepted in dtc! ;-)

> In this case, the dtc shipped with the linux kernel is simply used.
> This was considered to be sufficient for most cases.

Probably, yes.

> If this is not true and there really is a need for the separate dtc
> package, I think we should link both together in some way, either by a
> comment, or by a mutually exclusive configuration, or ...

OK for a comment for now.

What could probbably be done, later, is to make the dtc package a host
package too, and have the Linux kernel depends on, and use it, instead
of its internal copy (that can be lagging behind).

Does that sound reasonable to you?

Regards,
Yann E. MORIN.