[Buildroot] [PATCHv7 0/5] Keeping customizations outside the Buildroot tree with BR2_EXTERNAL

[Buildroot] [PATCHv7 0/5] Keeping customizations outside the Buildroot tree with BR2_EXTERNAL

[Thomas Petazzoni]

Hello,

Here is the seventh version of the BR2_EXTERNAL patch series. Its main
purpose is to take into account the feedback received recently on the
list.

People interested in testing this can find a branch at
http://git.free-electrons.com/users/thomas-petazzoni/buildroot/log/?h=things-outside-br-v7.

Changes since v6
================

 * Various documentation improvements suggested by Ryan Barnett.

 * Added various tags offered by Ryan or Yann.

Changes since v5
================

 * Fix some typos in the documentation, noticed by Yann E. Morin.

 * Split the manual generation fixes patch into two patches: one
   changing the regexp, now first in the series, and another one
   passing BR2_EXTERNAL, squashed with the core infrastructure.

Changes since v4
================

 * Include Arnout implementation of PATCH 1 (core infrastructure),
   which is indeed much simpler.

 * Add a dummy external.mk in support/dummy-external, which allows to
   remove the BR2_EXTERNAL_USED variable entirely.

 * Fix various typos in the documentation, reported by Yann and
   Arnout.

 * Integrate the new version of PATCH 5 (manual generation fixes),
   which includes a lot more details.

 * Fix the "make help" text according to Yann's suggestions.

Changes since v3
================

 * Fix the issue reported by Yann, where not having a
   output/.br-external file would make the build fail completely. I've
   fixed it in a slightly different way than the patch posted by Yann,
   though.

 * Revert back to the idea used in v2: include only a top-level
   BR2_EXTERNAL/Config.in file and a top-level
   BR2_EXTERNAL/external.mk. This way, the user of BR2_EXTERNAL is
   free to use it for target packages, host packages, bootloaders, and
   more. People have raised concern that enforcing the inclusion of
   BR2_EXTERNAL/package/Config.in was problematic, because they also
   wanted to add host tools in BR2_EXTERNAL/package/Config.in, and so
   on. So since people have differerent use cases, let's give some
   more flexibility.

Changes since v2
================

 * Remove the mechanism that was storing the BR2_EXTERNAL value in the
   external wrapper.

 * Add logic that stores the BR2_EXTERNAL value in a file called
   $(O)/.br-external. Whenever the user passes a BR2_EXTERNAL=<value>,
   it gets stored in this file, and Buildroot re-uses for all
   subsequent make invocations. The user can later override it again
   by passing another BR2_EXTERNAL=<value>. He can also remove it
   entirely by passing just BR2_EXTERNAL= (empty value).

 * Enforce usage of a package/ directory in the BR2_EXTERNAL
   directory. Buildroot only includes $(BR2_EXTERNAL)/Config.in and
   shows it under the "Target packages" menu, and Buildroot will only
   include $(BR2_EXTERNAL)/package/*/*.mk.

 * Clearly separate the Buildroot built-in defconfigs from the
   user-defined external defconfigs in the 'make help' output.

 * Include a fix for building the documentation, provided by Samuel
   Martin.

 * Update the documentation accordingly.

Changes since v1
================

 * Store BR2_EXTERNAL in the Makefile generated in the output
   directory, so that BR2_EXTERNAL doesn't have to be passed over and
   over again. Suggested by Ryan Barnett.

 * Patch set splitted in more fine-grained changes, as suggested by
   Arnout.

 * Instead of having the top-level Config.in file generated at
   run-time, use instead a trick proposed by Arnout: make BR2_EXTERNAL
   point to support/dummy-external/, which contains an empty
   Config.in. This way, regardless of whether BR2_EXTERNAL is
   specified by the user or not, kconfig is happy as 'source
   "$BR2_EXTERNAL/Config.in"' will always point to an existing
   file. If BR2_EXTERNAL is not used, it will point to the dummy file,
   if BR2_EXTERNAL is used, it will point to Config.in file in the
   provided BR2_EXTERNAL directory.

   With this, BR2_EXTERNAL always has a value, so testing whether
   BR2_EXTERNAL is empty no longer tells us if the user has provided a
   value or not. Therefore, we have another variable,
   BR2_EXTERNAL_USED, which tells if the mechanism is used by the user
   or not. This variable avoids trying to use defconfigs from the
   dummy directory, or to encode the BR2_EXTERNAL value in the
   Makefile wrapper.

 * As a consequence of the previous change, it is no longer needed to
   refactor the *config dependencies using a variable, so I've dropped
   what was previously the first patch of the series.

 * BR2_EXTERNAL is turned into an absolute path, in order to avoid any
   problem. Suggested by Arnout.

 * Fixed the usage of <some board> vs. <boardname> in the
   documentation, as noted by Arnout.

Thomas

Samuel Martin (1):
  manual: fix manual generation in preparation for BR2_EXTERNAL support

Thomas Petazzoni (4):
  core: introduce the BR2_EXTERNAL variable
  core: allow external Config.in/makefile code to be integrated
  core: allow external defconfigs to be used
  docs/manual: add explanations about BR2_EXTERNAL

 Config.in                            |   6 ++
 Makefile                             |  39 +++++++++-
 docs/manual/customize-outside-br.txt | 138 +++++++++++++++++++++++++++++++++++
 docs/manual/customize.txt            |   2 +
 docs/manual/manual.mk                |   3 +
 support/dummy-external/Config.in     |   0
 support/dummy-external/external.mk   |   0
 support/scripts/kconfiglib.py        |   2 +-
 8 files changed, 188 insertions(+), 2 deletions(-)
 create mode 100644 docs/manual/customize-outside-br.txt
 create mode 100644 support/dummy-external/Config.in
 create mode 100644 support/dummy-external/external.mk

-- 
1.8.1.2

[Buildroot] [PATCHv7 1/5] manual: fix manual generation in preparation for BR2_EXTERNAL support

[Thomas Petazzoni]

From: Samuel Martin <s.martin49@gmail.com>

This patch fixes an issue that occurs during the manual build process
which will occur when BR2_EXTERNAL is introduced.

During the package list generation, the python script using kconfiglib
module reads and parses the Config.in files. So, symbols, including
environment variables, got expanded and/or resolved.  In
kconfiglib.py, this patch fixes the regex that did not allow to use
numbers in the environment variable names, so '$BR2_EXTERNAL' got
wrongly expanded like it was '${BR}2_EXTERNAL':

<snip>
>>>   Updating the manual lists...
Traceback (most recent call last):
  File "/opt/buildroot/master/support/scripts/gen-manual-lists.py", line 375, in <module>
    buildroot = Buildroot()
  File "/opt/buildroot/master/support/scripts/gen-manual-lists.py", line 216, in __init__
    self.root_config))
  File "/opt/buildroot/master/support/scripts/kconfiglib.py", line 214, in __init__
    self.top_block = self._parse_file(filename, None, None, None)
  File "/opt/src/buildroot/master/support/scripts/kconfiglib.py", line 919, in _parse_file
    return self._parse_block(line_feeder, None, parent, deps, visible_if_deps, res)
  File "/opt/buildroot/master/support/scripts/kconfiglib.py", line 1114, in _parse_block
    self.base_dir))
IOError: /opt/buildroot/master/Config.in:490: sourced file "$BR2_EXTERNAL/Config.in" (expands to
"2_EXTERNAL/Config.in") not found. Perhaps base_dir
(argument to Config.__init__(), currently
"/opt/buildroot/master") is set to the wrong value.
docs/manual/manual.mk:2: recipe for target 'manual-update-lists' failed
make: *** [manual-update-lists] Error 1
</snip>

Reported-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Acked-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
---
 support/scripts/kconfiglib.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/support/scripts/kconfiglib.py b/support/scripts/kconfiglib.py
index 0704cc0..e40947c 100644
--- a/support/scripts/kconfiglib.py
+++ b/support/scripts/kconfiglib.py
@@ -2074,7 +2074,7 @@ set_re   = re.compile(r"CONFIG_(\w+)=(.*)")
 unset_re = re.compile(r"# CONFIG_(\w+) is not set")
 
 # Regular expression for finding $-references to symbols in strings
-sym_ref_re = re.compile(r"\$[A-Za-z_]+")
+sym_ref_re = re.compile(r"\$[A-Za-z_][0-9A-Za-z_]*")
 
 # Integers representing symbol types
 UNKNOWN, BOOL, TRISTATE, STRING, HEX, INT = range(0, 6)
-- 
1.8.1.2

[Buildroot] [PATCHv7 2/5] core: introduce the BR2_EXTERNAL variable

[Thomas Petazzoni]

This commit introduces the BR2_EXTERNAL environment variable, which
will allow to keep Buildroot customization (board-specific
configuration files or root filesystem overlays, package Config.in and
makefiles, as well as defconfigs) outside of the Buildroot tree.

This commit only introduces the variable itself, and ensures that it
is available within Config.in options. This allows us to use
$BR2_EXTERNAL in a 'source' statement in Config.in.

Following patches extend the usage of BR2_EXTERNAL to other areas
(packages and defconfigs).

In details, this commit:

 * Introduces the BR2_EXTERNAL Kconfig option. This option has no
   prompt, and is therefore not visible to the user and also not
   stored in the .config file. It is automatically set to the value of
   the BR2_EXTERNAL environment variable. The only purpose of this
   BR2_EXTERNAL Kconfig option is to allow $BR2_EXTERNAL to be
   properly expanded when used inside Kconfig source statements.

 * Calculates the BR2_EXTERNAL value to use. If passed on the command
   line, then this value is taken in priority, and saved to a
   .br-external hidden file in the output directory. If not passed on
   the command line, then we read the .br-external file from the
   output directory. This allows the user to not pass the BR2_EXTERNAL
   value at each make invocation. If no BR2_EXTERNAL value is passed,
   we define it to support/dummy-external, so that the kconfig code
   finds an existing $(BR2_EXTERNAL)/package/Config.in file to
   include.

 * Passes the BR2_EXTERNAL into the *config environment, so that its
   value is found when parsing/evaluating Config.in files and .config
   values.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Acked-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
---
 Config.in             |  4 ++++
 Makefile              | 26 +++++++++++++++++++++++++-
 docs/manual/manual.mk |  3 +++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/Config.in b/Config.in
index 677fff6..ea060bc 100644
--- a/Config.in
+++ b/Config.in
@@ -14,6 +14,10 @@ config BR2_HOSTARCH
 	string
 	option env="HOSTARCH"
 
+config BR2_EXTERNAL
+	string
+	option env="BR2_EXTERNAL"
+
 # Hidden boolean selected by pre-built packages for x86, when they
 # need to run on x86-64 machines (example: pre-built external
 # toolchains, binary tools like SAM-BA, etc.).
diff --git a/Makefile b/Makefile
index 6c28a86..e94c0bd 100644
--- a/Makefile
+++ b/Makefile
@@ -99,6 +99,29 @@ export CDPATH:=
 BASE_DIR := $(shell mkdir -p $(O) && cd $(O) >/dev/null && pwd)
 $(if $(BASE_DIR),, $(error output directory "$(O)" does not exist))
 
+
+# Handling of BR2_EXTERNAL.
+#
+# The value of BR2_EXTERNAL is stored in .br-external in the output directory.
+# On subsequent invocations of make, it is read in. It can still be overridden
+# on the command line, therefore the file is re-created every time make is run.
+#
+# When BR2_EXTERNAL is not set, the .br-external file is removed and we point
+# to support/dummy-external. This makes sure we can unconditionally include the
+# Config.in and external.mk from the BR2_EXTERNAL directory. In this case,
+# override is necessary so the user can clear BR2_EXTERNAL from the command
+# line, but the dummy path is still used internally.
+
+BR2_EXTERNAL_FILE = $(BASE_DIR)/.br-external
+-include $(BR2_EXTERNAL_FILE)
+ifeq ($(BR2_EXTERNAL),)
+  override BR2_EXTERNAL = support/dummy-external
+  $(shell rm -f $(BR2_EXTERNAL_FILE))
+else
+  $(shell echo BR2_EXTERNAL ?= $(BR2_EXTERNAL) > $(BR2_EXTERNAL_FILE))
+endif
+
+
 BUILD_DIR:=$(BASE_DIR)/build
 STAMP_DIR:=$(BASE_DIR)/stamps
 BINARIES_DIR:=$(BASE_DIR)/images
@@ -632,7 +655,8 @@ COMMON_CONFIG_ENV = \
 	KCONFIG_AUTOCONFIG=$(BUILD_DIR)/buildroot-config/auto.conf \
 	KCONFIG_AUTOHEADER=$(BUILD_DIR)/buildroot-config/autoconf.h \
 	KCONFIG_TRISTATE=$(BUILD_DIR)/buildroot-config/tristate.config \
-	BUILDROOT_CONFIG=$(BUILDROOT_CONFIG)
+	BUILDROOT_CONFIG=$(BUILDROOT_CONFIG) \
+	BR2_EXTERNAL=$(BR2_EXTERNAL)
 
 xconfig: $(BUILD_DIR)/buildroot-config/qconf outputmakefile
 	@mkdir -p $(BUILD_DIR)/buildroot-config
diff --git a/docs/manual/manual.mk b/docs/manual/manual.mk
index 0926566..506af05 100644
--- a/docs/manual/manual.mk
+++ b/docs/manual/manual.mk
@@ -1,6 +1,9 @@
+# Packages included in BR2_EXTERNAL are not part of buildroot, so they
+# should not be included in the manual.
 manual-update-lists: manual-check-dependencies-lists
 	$(Q)$(call MESSAGE,"Updating the manual lists...")
 	$(Q)BR2_DEFCONFIG="" TOPDIR=$(TOPDIR) O=$(O)/docs/manual/.build \
+		BR2_EXTERNAL=$(TOPDIR)/support/dummy-external \
 		$(TOPDIR)/support/scripts/gen-manual-lists.py
 
 # we can't use suitable-host-package here because that's not available in
-- 
1.8.1.2

[Buildroot] [PATCHv7 3/5] core: allow external Config.in/makefile code to be integrated

[Thomas Petazzoni]

This commit allows the BR2_EXTERNAL directory to contain Config.in and
Makefile code, which gets integrated into the Buildroot build logic:

 - Buildroot automatically includes the $BR2_EXTERNAL/Config.in in the
   top-level configuration menu.

 - Buildroot automatically includes the BR2_EXTERNAL/external.mk in
   the build logic, so it can for example be used to include other .mk
   files that define package recipes.

This is typically intended to be used to create target packages in the
BR2_EXTERNAL directory, but can also be used for bootloaders, host
packages, or other custom make logic.

We also add a dummy Config.in file in support/dummy-external/ to
ensure that the source "$BR2_EXTERNAL/Config.in" line will point to an
existing file even when BR2_EXTERNAL is not used by the user.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Acked-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
---
 Config.in                          | 2 ++
 Makefile                           | 2 ++
 support/dummy-external/Config.in   | 0
 support/dummy-external/external.mk | 0
 4 files changed, 4 insertions(+)
 create mode 100644 support/dummy-external/Config.in
 create mode 100644 support/dummy-external/external.mk

diff --git a/Config.in b/Config.in
index ea060bc..12d36b5 100644
--- a/Config.in
+++ b/Config.in
@@ -492,3 +492,5 @@ source "boot/Config.in"
 source "package/Config.in.host"
 
 source "Config.in.legacy"
+
+source "$BR2_EXTERNAL/Config.in"
diff --git a/Makefile b/Makefile
index e94c0bd..4f20bd5 100644
--- a/Makefile
+++ b/Makefile
@@ -364,6 +364,8 @@ include boot/common.mk
 include linux/linux.mk
 include system/system.mk
 
+include $(BR2_EXTERNAL)/external.mk
+
 TARGETS+=target-finalize
 
 ifeq ($(BR2_ENABLE_LOCALE_PURGE),y)
diff --git a/support/dummy-external/Config.in b/support/dummy-external/Config.in
new file mode 100644
index 0000000..e69de29
diff --git a/support/dummy-external/external.mk b/support/dummy-external/external.mk
new file mode 100644
index 0000000..e69de29
-- 
1.8.1.2

[Buildroot] [PATCHv7 4/5] core: allow external defconfigs to be used

[Thomas Petazzoni]

This commit allows the user to store defconfigs in
$BR2_EXTERNAL/configs/. To achieve this:

 * It adds a new %_defconfig that looks in $BR2_EXTERNAL/configs/ for
   the corresponding defconfig file.

 * Updates the help target to also list external defconfigs.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Acked-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
---
 Makefile | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Makefile b/Makefile
index 4f20bd5..3365a50 100644
--- a/Makefile
+++ b/Makefile
@@ -742,6 +742,10 @@ defconfig: $(BUILD_DIR)/buildroot-config/conf outputmakefile
 	@mkdir -p $(BUILD_DIR)/buildroot-config
 	@$(COMMON_CONFIG_ENV) $< --defconfig=$(TOPDIR)/configs/$@ $(CONFIG_CONFIG_IN)
 
+%_defconfig: $(BUILD_DIR)/buildroot-config/conf $(BR2_EXTERNAL)/configs/%_defconfig outputmakefile
+	@mkdir -p $(BUILD_DIR)/buildroot-config
+	@$(COMMON_CONFIG_ENV) $< --defconfig=$(BR2_EXTERNAL)/configs/$@ $(CONFIG_CONFIG_IN)
+
 savedefconfig: $(BUILD_DIR)/buildroot-config/conf outputmakefile
 	@mkdir -p $(BUILD_DIR)/buildroot-config
 	@$(COMMON_CONFIG_ENV) $< \
@@ -850,8 +854,15 @@ endif
 	@echo '  make V=0|1             - 0 => quiet build (default), 1 => verbose build'
 	@echo '  make O=dir             - Locate all output files in "dir", including .config'
 	@echo
+	@echo 'Built-in configs:'
 	@$(foreach b, $(sort $(notdir $(wildcard $(TOPDIR)/configs/*_defconfig))), \
 	  printf "  %-35s - Build for %s\\n" $(b) $(b:_defconfig=);)
+ifneq ($(wildcard $(BR2_EXTERNAL)/configs/*_defconfig),)
+	@echo
+	@echo 'User-provided configs:'
+	@$(foreach b, $(sort $(notdir $(wildcard $(BR2_EXTERNAL)/configs/*_defconfig))), \
+	  printf "  %-35s - Build for %s\\n" $(b) $(b:_defconfig=);)
+endif
 	@echo
 	@echo 'See docs/README, or generate the Buildroot manual for further details'
 	@echo
-- 
1.8.1.2

[Buildroot] [PATCHv7 5/5] docs/manual: add explanations about BR2_EXTERNAL

[Thomas Petazzoni]

This commit updates the manual to add details on how to use the
BR2_EXTERNAL feature.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
---
 docs/manual/customize-outside-br.txt | 138 +++++++++++++++++++++++++++++++++++
 docs/manual/customize.txt            |   2 +
 2 files changed, 140 insertions(+)
 create mode 100644 docs/manual/customize-outside-br.txt

diff --git a/docs/manual/customize-outside-br.txt b/docs/manual/customize-outside-br.txt
new file mode 100644
index 0000000..b2be419
--- /dev/null
+++ b/docs/manual/customize-outside-br.txt
@@ -0,0 +1,138 @@
+// -*- mode:doc -*- ;
+
+[[outside-br-custom]]
+Keeping customization outside Buildroot
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The Buildroot community recommends and encourages upstreaming to the
+official Buildroot version the packages and board supports that are
+written by developers. However, it is sometimes not possible or
+desirable because some of these packages or board supports are highly
+specific or proprietary.
+
+In this case, Buildroot users are offered two choices:
+
+ * They can add their packages, board support and configuration files
+   directly within the Buildroot tree, and maintain them by using
+   branches in a version control system.
+
+ * They can use the +BR2_EXTERNAL+ mechanism, which allows to keep
+   package recipes, board support and configuration files outside of
+   the Buildroot tree, while still having them nicely integrated in
+   the build logic. The following paragraphs give details on how to
+   use +BR2_EXTERNAL+.
+
++BR2_EXTERNAL+ is an environment variable that can be used to point to
+a directory that contains Buildroot customizations. It can be passed
+to any Buildroot +make+ invocation. It is automatically saved in the
+hidden +.br-external+ file in the output directory. By doing this,
+there is no need to pass +BR2_EXTERNAL+ at every +make+ invocation. It
+can however be changed at any time by passing a new value, and can be
+removed by passing an empty value.
+
+The +BR2_EXTERNAL+ path can be either an absolute or a relative path,
+but if it's passed as a relative path, it is important to note that it
+is interpreted relatively to the main Buildroot source directory, not
+the Buildroot output directory.
+
+Some examples:
+
+-----
+ buildroot/ $ make BR2_EXTERNAL=../foobar menuconfig
+-----
+
+Starting from now on, external definitions from the +../foobar+
+directory will be used:
+
+-----
+ buildroot/ $ make
+ buildroot/ $ make legal-info
+-----
+
+We can switch to another external definitions directory at any time:
+
+-----
+ buildroot/ $ make BR2_EXTERNAL=../barfoo xconfig
+-----
+
+Or disable the usage of external definitions:
+
+-----
+ buildroot/ $ make BR2_EXTERNAL= xconfig
+-----
+
++BR2_EXTERNAL+ then allows three different things:
+
+ * One can store all the board-specific configuration files there,
+   such as the kernel configuration, the root filesystem overlay, or
+   any other configuration file for which Buildroot allows to set its
+   location. The +BR2_EXTERNAL+ value is available within the
+   Buildroot configuration using +$(BR2_EXTERNAL)+. As an example, one
+   could set the +BR2_ROOTFS_OVERLAY+ Buildroot option to
+   +$(BR2_EXTERNAL)/board/<boardname>/overlay/+ (to specify a root
+   filesystem overlay), or the +BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE+
+   Buildroot option to
+   +$(BR2_EXTERNAL)/board/<boardname>/kernel.config+ (to specify the
+   location of the kernel configuration file). To achieve this, it is
+   recommended but not mandatory, to store those details in
+   directories called +board/<boardname>/+ under +BR2_EXTERNAL+. This
+   matches the directory structure used within Buildroot.
+
+ * One can store package recipes (i.e +Config.in+ and
+   +<packagename>.mk+), or even custom configuration options and make
+   logic. Buildroot automatically includes +BR2_EXTERNAL/Config.in+ to
+   make it appear in the top-level configuration menu, and includes
+   +BR2_EXTERNAL/external.mk+ with the rest of the makefile logic.
++
+The main usage of this is to store package recipes. The recommended
+   way to do this is to write a +BR2_EXTERNAL/Config.in+ that looks
+   like:
++
+------
+menu "<somecompany> packages"
+
+source "$BR2_EXTERNAL/package/package1/Config.in"
+source "$BR2_EXTERNAL/package/package2/Config.in"
+
+endmenu
+------
++
+Then, have a +BR2_EXTERNAL/external.mk+ file that looks like:
++
+------
+include $(sort $(wildcard $(BR2_EXTERNAL)/package/*/*.mk))
+------
++
+And then in +BR2_EXTERNAL/package/package1+ and
+   +BR2_EXTERNAL/package/package2+ create normal Buildroot package
+   recipes, as explained in xref:adding-packages[].
+
+ * One can store Buildroot defconfigs in the +configs+ subdirectory of
+   +BR2_EXTERNAL+. Buildroot will automatically show them in the
+   output of +make help+ and allow them to be loaded with the normal
+   +make <name>_defconfig+ command. They will be visible under the
+   +User-provided configs:' label in the 'make help' output.
+
+In the end, a typical +BR2_EXTERNAL+ directory organization would
+generally be:
+
+-----
+$(BR2_EXTERNAL)/
++-- Config.in
++-- external.mk
++-- board/
+|   +-- <boardname>/
+|       +-- linux.config
+|       +-- overlay/
+|           +-- etc/
+|               +-- <some file>
++-- configs/
+|   +-- <boardname>_defconfig
++-- package/
+    +-- package1/
+    |    +-- Config.in
+    |    +-- package1.mk
+    +-- package2/
+        +-- Config.in
+        +-- package2.mk
+------
diff --git a/docs/manual/customize.txt b/docs/manual/customize.txt
index 0456ef1..7e46fd8 100644
--- a/docs/manual/customize.txt
+++ b/docs/manual/customize.txt
@@ -17,3 +17,5 @@ include::customize-toolchain.txt[]
 include::customize-store.txt[]
 
 include::customize-packages.txt[]
+
+include::customize-outside-br.txt[]
-- 
1.8.1.2

[Buildroot] [PATCHv7 5/5] docs/manual: add explanations about BR2_EXTERNAL

[Samuel Martin]

Thomas, all,


2013/12/5 Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

> This commit updates the manual to add details on how to use the
> BR2_EXTERNAL feature.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> ---
>  docs/manual/customize-outside-br.txt | 138
> +++++++++++++++++++++++++++++++++++
>  docs/manual/customize.txt            |   2 +
>  2 files changed, 140 insertions(+)
>  create mode 100644 docs/manual/customize-outside-br.txt
>
> diff --git a/docs/manual/customize-outside-br.txt
> b/docs/manual/customize-outside-br.txt
> new file mode 100644
> index 0000000..b2be419
> --- /dev/null
> +++ b/docs/manual/customize-outside-br.txt
> @@ -0,0 +1,138 @@
> +// -*- mode:doc -*- ;
> +
> +[[outside-br-custom]]
> +Keeping customization outside Buildroot
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +The Buildroot community recommends and encourages upstreaming to the
> +official Buildroot version the packages and board supports that are
> +written by developers. However, it is sometimes not possible or
> +desirable because some of these packages or board supports are highly
> +specific or proprietary.
> +
> +In this case, Buildroot users are offered two choices:
> +
> + * They can add their packages, board support and configuration files
> +   directly within the Buildroot tree, and maintain them by using
> +   branches in a version control system.
> +
> + * They can use the +BR2_EXTERNAL+ mechanism, which allows to keep
> +   package recipes, board support and configuration files outside of
> +   the Buildroot tree, while still having them nicely integrated in
> +   the build logic. The following paragraphs give details on how to
> +   use +BR2_EXTERNAL+.
> +
> ++BR2_EXTERNAL+ is an environment variable that can be used to point to
> +a directory that contains Buildroot customizations. It can be passed
> +to any Buildroot +make+ invocation. It is automatically saved in the
> +hidden +.br-external+ file in the output directory. By doing this,
> +there is no need to pass +BR2_EXTERNAL+ at every +make+ invocation. It
> +can however be changed at any time by passing a new value, and can be
> +removed by passing an empty value.
> +
> +The +BR2_EXTERNAL+ path can be either an absolute or a relative path,
> +but if it's passed as a relative path, it is important to note that it
> +is interpreted relatively to the main Buildroot source directory, not
> +the Buildroot output directory.
> +
> +Some examples:
> +
> +-----
> + buildroot/ $ make BR2_EXTERNAL=../foobar menuconfig
> +-----
> +
> +Starting from now on, external definitions from the +../foobar+
> +directory will be used:
> +
> +-----
> + buildroot/ $ make
> + buildroot/ $ make legal-info
> +-----
> +
> +We can switch to another external definitions directory at any time:
> +
> +-----
> + buildroot/ $ make BR2_EXTERNAL=../barfoo xconfig
> +-----
> +
> +Or disable the usage of external definitions:
> +
> +-----
> + buildroot/ $ make BR2_EXTERNAL= xconfig
> +-----
> +
> ++BR2_EXTERNAL+ then allows three different things:
> +
> + * One can store all the board-specific configuration files there,
> +   such as the kernel configuration, the root filesystem overlay, or
> +   any other configuration file for which Buildroot allows to set its
> +   location. The +BR2_EXTERNAL+ value is available within the
> +   Buildroot configuration using +$(BR2_EXTERNAL)+. As an example, one
> +   could set the +BR2_ROOTFS_OVERLAY+ Buildroot option to
> +   +$(BR2_EXTERNAL)/board/<boardname>/overlay/+ (to specify a root
> +   filesystem overlay), or the +BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE+
> +   Buildroot option to
> +   +$(BR2_EXTERNAL)/board/<boardname>/kernel.config+ (to specify the
> +   location of the kernel configuration file). To achieve this, it is
> +   recommended but not mandatory, to store those details in
> +   directories called +board/<boardname>/+ under +BR2_EXTERNAL+. This
> +   matches the directory structure used within Buildroot.
> +
> + * One can store package recipes (i.e +Config.in+ and
> +   +<packagename>.mk+), or even custom configuration options and make
> +   logic. Buildroot automatically includes +BR2_EXTERNAL/Config.in+ to
> +   make it appear in the top-level configuration menu, and includes
> +   +BR2_EXTERNAL/external.mk+ with the rest of the makefile logic.
> ++
> +The main usage of this is to store package recipes. The recommended
> +   way to do this is to write a +BR2_EXTERNAL/Config.in+ that looks
> +   like:
> ++
> +------
> +menu "<somecompany> packages"
> +
> +source "$BR2_EXTERNAL/package/package1/Config.in"
> +source "$BR2_EXTERNAL/package/package2/Config.in"
> +
> +endmenu
> +------
> ++
> +Then, have a +BR2_EXTERNAL/external.mk+ file that looks like:
> ++
> +------
> +include $(sort $(wildcard $(BR2_EXTERNAL)/package/*/*.mk))
> +------
> ++
> +And then in +BR2_EXTERNAL/package/package1+ and
> +   +BR2_EXTERNAL/package/package2+ create normal Buildroot package
> +   recipes, as explained in xref:adding-packages[].
> +
> + * One can store Buildroot defconfigs in the +configs+ subdirectory of
> +   +BR2_EXTERNAL+. Buildroot will automatically show them in the
> +   output of +make help+ and allow them to be loaded with the normal
> +   +make <name>_defconfig+ command. They will be visible under the
> +   +User-provided configs:' label in the 'make help' output.
>
For "User-provided configs:", what style do you choose? ;)

+
> +In the end, a typical +BR2_EXTERNAL+ directory organization would
> +generally be:
> +
> +-----
> +$(BR2_EXTERNAL)/
> ++-- Config.in
> ++-- external.mk
> ++-- board/
> +|   +-- <boardname>/
> +|       +-- linux.config
> +|       +-- overlay/
> +|           +-- etc/
> +|               +-- <some file>
> ++-- configs/
> +|   +-- <boardname>_defconfig
> ++-- package/
> +    +-- package1/
> +    |    +-- Config.in
> +    |    +-- package1.mk
> +    +-- package2/
> +        +-- Config.in
> +        +-- package2.mk
> +------
> diff --git a/docs/manual/customize.txt b/docs/manual/customize.txt
> index 0456ef1..7e46fd8 100644
> --- a/docs/manual/customize.txt
> +++ b/docs/manual/customize.txt
> @@ -17,3 +17,5 @@ include::customize-toolchain.txt[]
>  include::customize-store.txt[]
>
>  include::customize-packages.txt[]
> +
> +include::customize-outside-br.txt[]
> --
> 1.8.1.2
>
>
With the above thing fixed:
Acked-by: "Samuel Martin" <s.martin49@gmail.com>

Regrads,

-- 
Samuel
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[Buildroot] [PATCHv7 2/5] core: introduce the BR2_EXTERNAL variable

[Samuel Martin]

2013/12/5 Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

> This commit introduces the BR2_EXTERNAL environment variable, which
> will allow to keep Buildroot customization (board-specific
> configuration files or root filesystem overlays, package Config.in and
> makefiles, as well as defconfigs) outside of the Buildroot tree.
>
> This commit only introduces the variable itself, and ensures that it
> is available within Config.in options. This allows us to use
> $BR2_EXTERNAL in a 'source' statement in Config.in.
>
> Following patches extend the usage of BR2_EXTERNAL to other areas
> (packages and defconfigs).
>
> In details, this commit:
>
>  * Introduces the BR2_EXTERNAL Kconfig option. This option has no
>    prompt, and is therefore not visible to the user and also not
>    stored in the .config file. It is automatically set to the value of
>    the BR2_EXTERNAL environment variable. The only purpose of this
>    BR2_EXTERNAL Kconfig option is to allow $BR2_EXTERNAL to be
>    properly expanded when used inside Kconfig source statements.
>
>  * Calculates the BR2_EXTERNAL value to use. If passed on the command
>    line, then this value is taken in priority, and saved to a
>    .br-external hidden file in the output directory. If not passed on
>    the command line, then we read the .br-external file from the
>    output directory. This allows the user to not pass the BR2_EXTERNAL
>    value at each make invocation. If no BR2_EXTERNAL value is passed,
>    we define it to support/dummy-external, so that the kconfig code
>    finds an existing $(BR2_EXTERNAL)/package/Config.in file to
>    include.
>
>  * Passes the BR2_EXTERNAL into the *config environment, so that its
>    value is found when parsing/evaluating Config.in files and .config
>    values.
>
> Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Acked-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
>
Tested-by: "Samuel Martin" <s.martin49@gmail.com>
Acked-by: "Samuel Martin" <s.martin49@gmail.com>


Regards,

-- 
Samuel
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[Buildroot] [PATCHv7 3/5] core: allow external Config.in/makefile code to be integrated

[Samuel Martin]

2013/12/5 Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

> This commit allows the BR2_EXTERNAL directory to contain Config.in and
> Makefile code, which gets integrated into the Buildroot build logic:
>
>  - Buildroot automatically includes the $BR2_EXTERNAL/Config.in in the
>    top-level configuration menu.
>
>  - Buildroot automatically includes the BR2_EXTERNAL/external.mk in
>    the build logic, so it can for example be used to include other .mk
>    files that define package recipes.
>
> This is typically intended to be used to create target packages in the
> BR2_EXTERNAL directory, but can also be used for bootloaders, host
> packages, or other custom make logic.
>
> We also add a dummy Config.in file in support/dummy-external/ to
> ensure that the source "$BR2_EXTERNAL/Config.in" line will point to an
> existing file even when BR2_EXTERNAL is not used by the user.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Acked-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
>
Tested-by: "Samuel Martin" <s.martin49@gmail.com>
Acked-by: "Samuel Martin" <s.martin49@gmail.com>


Regards,

-- 
Samuel
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[Buildroot] [PATCHv7 4/5] core: allow external defconfigs to be used

[Samuel Martin]

2013/12/5 Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

> This commit allows the user to store defconfigs in
> $BR2_EXTERNAL/configs/. To achieve this:
>
>  * It adds a new %_defconfig that looks in $BR2_EXTERNAL/configs/ for
>    the corresponding defconfig file.
>
>  * Updates the help target to also list external defconfigs.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Acked-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
>
Tested-by: "Samuel Martin" <s.martin49@gmail.com>
Acked-by: "Samuel Martin" <s.martin49@gmail.com>


Regards,

--
Samuel
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[Buildroot] [PATCHv7 2/5] core: introduce the BR2_EXTERNAL variable

[Arnout Vandecappelle]

On 05/12/13 20:11, Thomas Petazzoni wrote:
> +BR2_EXTERNAL_FILE = $(BASE_DIR)/.br-external
> +-include $(BR2_EXTERNAL_FILE)
> +ifeq ($(BR2_EXTERNAL),)
> +  override BR2_EXTERNAL = support/dummy-external
> +  $(shell rm -f $(BR2_EXTERNAL_FILE))
> +else
> +  $(shell echo BR2_EXTERNAL ?= $(BR2_EXTERNAL) > $(BR2_EXTERNAL_FILE))
> +endif

  Huh, did I write this? AFAIK we don't normally indent inside make 
conditionals... And if we did, it would be with tabs.

  Regards,
  Arnout

-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7CB5 E4CC 6C2E EFD4 6E3D A754 F963 ECAB 2450 2F1F

[Buildroot] [PATCHv7 5/5] docs/manual: add explanations about BR2_EXTERNAL

[Ryan Barnett]

Thomas P,

Thomas Petazzoni <thomas.petazzoni@free-electrons.com> wrote on 12/05/2013 
01:11:13 PM:

> This commit updates the manual to add details on how to use the
> BR2_EXTERNAL feature.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> ---
>  docs/manual/customize-outside-br.txt | 138 
+++++++++++++++++++++++++++++++++++
>  docs/manual/customize.txt            |   2 +
>  2 files changed, 140 insertions(+)
>  create mode 100644 docs/manual/customize-outside-br.txt

Acked-by: Ryan Barnett <rjbarnet@rockwellcollins.com>
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[Buildroot] [PATCHv7 3/5] core: allow external Config.in/makefile code to be integrated

[Peter Korsgaard]

>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:

 > This commit allows the BR2_EXTERNAL directory to contain Config.in and
 > Makefile code, which gets integrated into the Buildroot build logic:

 >  - Buildroot automatically includes the $BR2_EXTERNAL/Config.in in the
 >    top-level configuration menu.

 >  - Buildroot automatically includes the BR2_EXTERNAL/external.mk in
 >    the build logic, so it can for example be used to include other .mk
 >    files that define package recipes.

 > This is typically intended to be used to create target packages in the
 > BR2_EXTERNAL directory, but can also be used for bootloaders, host
 > packages, or other custom make logic.

 > We also add a dummy Config.in file in support/dummy-external/ to
 > ensure that the source "$BR2_EXTERNAL/Config.in" line will point to an
 > existing file even when BR2_EXTERNAL is not used by the user.

[snip]

 > diff --git a/Config.in b/Config.in
 > index ea060bc..12d36b5 100644
 > --- a/Config.in
 > +++ b/Config.in
 > @@ -492,3 +492,5 @@ source "boot/Config.in"
 >  source "package/Config.in.host"
 
 >  source "Config.in.legacy"
 > +
 > +source "$BR2_EXTERNAL/Config.in"

Should we perhaps add a comment before or put this inside a 'menu' so it
is clear that these things are NOT part of Buildroot and people
shouldn't ask the buildroot list for support for them?

Having a comment / empty menu when this isn't use is a bit annoying, but
we could perhaps use:

    depends on BR2_EXTERNAL != "support/dummy-external"

I haven't tested if that works though.

-- 
Bye, Peter Korsgaard

[Buildroot] [PATCHv7 5/5] docs/manual: add explanations about BR2_EXTERNAL

[Peter Korsgaard]

>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:

 > This commit updates the manual to add details on how to use the
 > BR2_EXTERNAL feature.

 > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
 > Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

I'm no native speaker, but there's a few things I think sound odd:

 > +[[outside-br-custom]]
 > +Keeping customization outside Buildroot
 > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I think it should be 'customizations'

 > +
 > +The Buildroot community recommends and encourages upstreaming to the
 > +official Buildroot version the packages and board supports that are
 > +written by developers. However, it is sometimes not possible or
 > +desirable because some of these packages or board supports are highly
 > +specific or proprietary.

And 'board support', not supports.

Committed with that fixed (and the missing + as pointed out by Samuel),
thanks.

-- 
Bye, Peter Korsgaard

[Buildroot] [PATCHv7 0/5] Keeping customizations outside the Buildroot tree with BR2_EXTERNAL

[Peter Korsgaard]

>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:

 > Hello,
 > Here is the seventh version of the BR2_EXTERNAL patch series. Its main
 > purpose is to take into account the feedback received recently on the
 > list.

 > People interested in testing this can find a branch at
 > http://git.free-electrons.com/users/thomas-petazzoni/buildroot/log/?h=things-outside-br-v7.

Committed series, thanks everyone!

-- 
Bye, Peter Korsgaard

[Buildroot] [PATCHv7 0/5] Keeping customizations outside the Buildroot tree with BR2_EXTERNAL

[Arnout Vandecappelle]

On 08/12/13 23:02, Peter Korsgaard wrote:
>>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:
>
>   > Hello,
>   > Here is the seventh version of the BR2_EXTERNAL patch series. Its main
>   > purpose is to take into account the feedback received recently on the
>   > list.
>
>   > People interested in testing this can find a branch at
>   > http://git.free-electrons.com/users/thomas-petazzoni/buildroot/log/?h=things-outside-br-v7.
>
> Committed series, thanks everyone!

  Perhaps we should introduce an autobuilder or jenkins instance that has 
BR2_EXTERNAL set to include some helloworld application? Then we make 
sure that this code (which will not often be used by the core BR 
developers) will still work in the future.

  Regards,
  Arnout


-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7CB5 E4CC 6C2E EFD4 6E3D A754 F963 ECAB 2450 2F1F