b3a939367f
Updating the documentation to reflect that multiple directories can now be specified for BR2_GLOBAL_PATCH_DIR. Along with giving an example use case of how to use multiple global patch directories. [Thomas: fix minor typo mentionned by Thomas De Schampheleire.] Signed-off-by: Ryan Barnett <rjbarnet@rockwellcollins.com> Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com> Cc: Arnout Vandecappelle <arnout@mind.be> Reviewed-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
98 lines
3.5 KiB
Plaintext
98 lines
3.5 KiB
Plaintext
// -*- mode:doc -*- ;
|
|
|
|
[[packages-custom]]
|
|
Customizing packages
|
|
~~~~~~~~~~~~~~~~~~~~
|
|
|
|
It is sometimes useful to apply 'extra' patches to packages - over and
|
|
above those provided in Buildroot. This might be used to support custom
|
|
features in a project, for example, or when working on a new architecture.
|
|
|
|
The +BR2_GLOBAL_PATCH_DIR+ configuration option can be used to specify
|
|
a space separated list of one or more directories containing package
|
|
patches. By specifying multiple global patch directories, a user could
|
|
implement a layered approach to patches. This could be useful when a
|
|
user has multiple boards that share a common processor architecture.
|
|
It is often the case that a subset of patches for a package need to be
|
|
shared between the different boards a user has. However, each board
|
|
may require specific patches for the package that build on top of the
|
|
common subset of patches.
|
|
|
|
For a specific version +<packageversion>+ of a specific package
|
|
+<packagename>+, patches are applied from +BR2_GLOBAL_PATCH_DIR+ as
|
|
follows:
|
|
|
|
. For every directory - +<global-patch-dir>+ - that exists in
|
|
+BR2_GLOBAL_PATCH_DIR+, a +<package-patch-dir>+ will be determined as
|
|
follows:
|
|
+
|
|
* +<global-patch-dir>/<packagename>/<packageversion>/+ if the
|
|
directory exists.
|
|
+
|
|
* Otherwise, +<global-patch-dir>/<packagename>+ if the directory
|
|
exists.
|
|
|
|
. Patches will then be applied from a +<package-patch-dir>+ as
|
|
follows:
|
|
+
|
|
* If a +series+ file exists in the package directory, then patches are
|
|
applied according to the +series+ file;
|
|
+
|
|
* Otherwise, patch files matching +<packagename>-*.patch+
|
|
are applied in alphabetical order.
|
|
So, to ensure they are applied in the right order, it is highly
|
|
recommended to name the patch files like this:
|
|
+<packagename>-<number>-<description>.patch+, where +<number>+
|
|
refers to the 'apply order'.
|
|
|
|
For information about how patches are applied for a package, see
|
|
xref:patch-apply-order[]
|
|
|
|
The +BR2_GLOBAL_PATCH_DIR+ option is the preferred method for
|
|
specifying a custom patch directory for packages. It can be used to
|
|
specify a patch directory for any package in buildroot. It should also
|
|
be used in place of the custom patch directory options that are
|
|
available for packages such as U-Boot and Barebox. By doing this, it
|
|
will allow a user to manage their patches from one top-level
|
|
directory.
|
|
|
|
The exception to +BR2_GLOBAL_PATCH_DIR+ being the preferred method for
|
|
specifying custom patches is +BR2_LINUX_KERNEL_PATCH+.
|
|
+BR2_LINUX_KERNEL_PATCH+ should be used to specify kernel patches that
|
|
are available at an URL. *Note:* +BR2_LINUX_KERNEL_PATCHES+ are applied
|
|
after patches available in +BR2_GLOBAL_PATCH_DIR+, as it is done
|
|
from a post-patch hook of the Linux package.
|
|
|
|
An example directory structure for where a user has multiple
|
|
directories specified for +BR2_GLOBAL_PATCH_DIR+ may look like this:
|
|
|
|
-----
|
|
board/
|
|
+-- common-fooarch
|
|
| +-- patches
|
|
| +-- linux
|
|
| | +-- linux-patch1.patch
|
|
| | +-- linux-patch2.patch
|
|
| +-- u-boot
|
|
| +-- foopkg
|
|
+-- fooarch-board
|
|
+-- patches
|
|
+-- linux
|
|
| +-- linux-patch3.patch
|
|
+-- u-boot
|
|
+-- foopkg
|
|
-----
|
|
|
|
If the user has the +BR2_GLOBAL_PATCH_DIR+ configuration option set as
|
|
follows:
|
|
|
|
-----
|
|
BR2_GLOBAL_PATCH_DIR="board/common-fooarch board/fooarch-board"
|
|
-----
|
|
|
|
Then the patches would applied as follows for the Linux kernel:
|
|
|
|
. board/common-fooarch/patches/linux/linux-patch1.patch
|
|
. board/common-fooarch/patches/linux/linux-patch2.patch
|
|
. board/fooarch-board/patches/linux/linux-patch3.patch
|