documentation/kernel-dev/advanced.rst

4 Working with Advanced Metadata (``yocto-kernel-cache``)
12 :term:`Metadata` that you can use to define
14 the Metadata and the tools that manage it is to help you manage the
18 Kernel Metadata exists in many places. One area in the
31 Using Kernel Metadata in a Recipe
35 Metadata, which is located in the ``yocto-kernel-cache`` Git repository.
36 This Metadata defines Board Support Packages (BSPs) that correspond to
44    A Linux kernel recipe that contains kernel Metadata (e.g. inherits
87 within the kernel Metadata with which to build out the sources and
120 within the kernel Metadata itself. The examples here are taken from the
123 information, see the ":ref:`kernel-dev/advanced:kernel metadata syntax`"
126 Kernel Metadata Syntax
129 The kernel Metadata consists of three primary types of files: ``scc``
133 types of kernel Metadata into what ultimately describes the sources and
138 of kernel Metadata:
146 implement conceptually separate kernel Metadata descriptions such as
154 While the kernel Metadata syntax does not enforce any logical separation
156 practices dictate a logical separation of these types of Metadata. The
157 following Metadata file hierarchy is recommended::
189 impact on the functionality of the kernel Metadata. There is no impact
193 Paths used in kernel Metadata files are relative to base, which is
196 you are creating Metadata in
197 :ref:`recipe-space <kernel-dev/advanced:recipe-space metadata>`,
201 :ref:`kernel-dev/advanced:metadata outside the recipe-space`.
211 The simplest unit of kernel Metadata is the configuration-only feature.
218 recipe space (i.e. ``yocto-kernel-cache``). This Metadata consists of
278 ``yocto-kernel-cache``). This Metadata consists of several files:
328 Features are complex kernel Metadata types that consist of configuration
349 ":ref:`kernel-dev/advanced:using kernel metadata in a recipe`" section earlier
364 :ref:`require <bitbake:bitbake-user-manual/bitbake-user-manual-metadata:\`\`require\`\` directive>`…
381    ":ref:`kernel-dev/advanced:using kernel metadata in a recipe`"
402 For any given kernel type, the Metadata is defined by the ``.scc`` (e.g.
452 hardware-specific features. The hardware-specific Metadata is typically
514 kernel type defined in your kernel Metadata as it is here, you only need
574    Although the Minnow Board BSP is unused, the Metadata remains and is
662 Kernel Metadata Location
665 Kernel Metadata always exists outside of the kernel tree either defined
667 choose to define the Metadata depends on what you want to do and how you
668 intend to work. Regardless of where you define the kernel Metadata, the
677 kernel Metadata in the recipe-space, see the
682 more convenient to work with kernel Metadata kept outside the
683 recipe-space. Working with Metadata in this area can make iterative
687 Recipe-Space Metadata
690 When stored in recipe-space, the kernel Metadata files reside in a
700 Here is an example that shows a trivial tree of kernel Metadata stored
711 When the Metadata is stored in recipe-space, you must take steps to
730 Metadata Outside the Recipe-Space
733 When stored outside of the recipe-space, the kernel Metadata files
735 Metadata to the build as a "type=kmeta" repository through the
745 which the Git fetcher places the Metadata. This behavior is no different
749 You can keep kernel Metadata in a "kernel-cache", which is a directory
750 containing configuration fragments. As with any Metadata kept outside
752 the "type=kmeta" attribute. Doing so makes the kernel Metadata available
755 If you modify the Metadata, you must not forget to update the :term:`SRCREV`
820 Once you have a new branch, you can set up your kernel Metadata to use