70c7fbf0ae
As discussed on irc, there is a missing part in the BR2_GLOBAL_PATCH_DIR
example compared to the ASCII figure under customize-packages section.
Signed-off-by: Sebastien Roy <sebastien.roy@savoirfairelinux.com>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
97 lines
3.5 KiB
Plaintext
97 lines
3.5 KiB
Plaintext
// -*- mode:doc -*- ;
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[[packages-custom]]
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=== Customizing packages
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It is sometimes useful to apply 'extra' patches to packages - over and
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above those provided in Buildroot. This might be used to support custom
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features in a project, for example, or when working on a new architecture.
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The +BR2_GLOBAL_PATCH_DIR+ configuration option can be used to specify
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a space separated list of one or more directories containing package
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patches. By specifying multiple global patch directories, a user could
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implement a layered approach to patches. This could be useful when a
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user has multiple boards that share a common processor architecture.
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It is often the case that a subset of patches for a package need to be
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shared between the different boards a user has. However, each board
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may require specific patches for the package that build on top of the
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common subset of patches.
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For a specific version +<packageversion>+ of a specific package
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+<packagename>+, patches are applied from +BR2_GLOBAL_PATCH_DIR+ as
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follows:
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. For every directory - +<global-patch-dir>+ - that exists in
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+BR2_GLOBAL_PATCH_DIR+, a +<package-patch-dir>+ will be determined as
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follows:
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+
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* +<global-patch-dir>/<packagename>/<packageversion>/+ if the
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directory exists.
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+
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* Otherwise, +<global-patch-dir>/<packagename>+ if the directory
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exists.
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. Patches will then be applied from a +<package-patch-dir>+ as
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follows:
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+
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* If a +series+ file exists in the package directory, then patches are
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applied according to the +series+ file;
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+
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* Otherwise, patch files matching +<packagename>-*.patch+
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are applied in alphabetical order.
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So, to ensure they are applied in the right order, it is highly
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recommended to name the patch files like this:
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+<packagename>-<number>-<description>.patch+, where +<number>+
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refers to the 'apply order'.
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For information about how patches are applied for a package, see
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xref:patch-apply-order[]
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The +BR2_GLOBAL_PATCH_DIR+ option is the preferred method for
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specifying a custom patch directory for packages. It can be used to
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specify a patch directory for any package in buildroot. It should also
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be used in place of the custom patch directory options that are
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available for packages such as U-Boot and Barebox. By doing this, it
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will allow a user to manage their patches from one top-level
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directory.
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The exception to +BR2_GLOBAL_PATCH_DIR+ being the preferred method for
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specifying custom patches is +BR2_LINUX_KERNEL_PATCH+.
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+BR2_LINUX_KERNEL_PATCH+ should be used to specify kernel patches that
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are available at an URL. *Note:* +BR2_LINUX_KERNEL_PATCH+ specifies kernel
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patches that are applied after patches available in +BR2_GLOBAL_PATCH_DIR+,
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as it is done from a post-patch hook of the Linux package.
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An example directory structure for where a user has multiple
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directories specified for +BR2_GLOBAL_PATCH_DIR+ may look like this:
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-----
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board/
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+-- common-fooarch
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| +-- patches
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| +-- linux
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| | +-- linux-patch1.patch
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| | +-- linux-patch2.patch
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| +-- uboot
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| +-- foopkg
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+-- fooarch-board
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+-- patches
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+-- linux
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| +-- linux-patch3.patch
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+-- uboot
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+-- foopkg
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-----
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If the user has the +BR2_GLOBAL_PATCH_DIR+ configuration option set as
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follows:
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-----
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BR2_GLOBAL_PATCH_DIR="board/common-fooarch/patches board/fooarch-board/patches"
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-----
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Then the patches would applied as follows for the Linux kernel:
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. board/common-fooarch/patches/linux/linux-patch1.patch
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. board/common-fooarch/patches/linux/linux-patch2.patch
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. board/fooarch-board/patches/linux/linux-patch3.patch
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