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[v3] ref-manual: add documentation for the barebox class

Message ID 20250119221005.1586540-1-ejo@pengutronix.de
State Under Review
Headers show
Series [v3] ref-manual: add documentation for the barebox class | expand

Commit Message

Enrico Jörns Jan. 19, 2025, 10:10 p.m. UTC
This adds the initial documentation for the newly added barebox.bbclass
to the Reference Manual's class list.
It also adds the two most notable variables to the variable list.

Signed-off-by: Enrico Jörns <ejo@pengutronix.de>
---
v2 -> v3:
  - use three spaces for code block indentation
  - start barebox class variable descriptions with
    "When using the :ref:`ref-classes-barebox` class, .."
    and adapt paragraphs accordingly.

 documentation/ref-manual/classes.rst   | 37 ++++++++++++++++++++++++++
 documentation/ref-manual/variables.rst | 29 ++++++++++++++++++++
 2 files changed, 66 insertions(+)

Comments

Antonin Godard Jan. 20, 2025, 9:09 a.m. UTC | #1
Hi Enrico,

On Sun Jan 19, 2025 at 11:10 PM CET, Enrico Jörns wrote:
> This adds the initial documentation for the newly added barebox.bbclass
> to the Reference Manual's class list.
> It also adds the two most notable variables to the variable list.
>
> Signed-off-by: Enrico Jörns <ejo@pengutronix.de>
> ---
> v2 -> v3:
>   - use three spaces for code block indentation
>   - start barebox class variable descriptions with
>     "When using the :ref:`ref-classes-barebox` class, .."
>     and adapt paragraphs accordingly.
>
>  documentation/ref-manual/classes.rst   | 37 ++++++++++++++++++++++++++
>  documentation/ref-manual/variables.rst | 29 ++++++++++++++++++++
>  2 files changed, 66 insertions(+)

Reviewed-by: Antonin Godard <antonin.godard@bootlin.com>

Thank you,
Antonin
diff mbox series

Patch

diff --git a/documentation/ref-manual/classes.rst b/documentation/ref-manual/classes.rst
index 22c4301a4..8ad77319e 100644
--- a/documentation/ref-manual/classes.rst
+++ b/documentation/ref-manual/classes.rst
@@ -128,6 +128,43 @@  It's useful to have some idea of how the tasks defined by the
 -  :ref:`ref-tasks-install` --- runs ``make install`` and
    passes in ``${``\ :term:`D`\ ``}`` as ``DESTDIR``.
 
+.. _ref-classes-barebox:
+
+``barebox``
+===========
+
+The :ref:`ref-classes-barebox` class manages building the barebox bootloader.
+
+If a file named ``defconfig`` is included in the :term:`SRC_URI`, it will be
+copied to ``.config`` in the build directory and used as the barebox
+configuration.
+Instead of providing a ``defconfig`` file, you can set :term:`BAREBOX_CONFIG`
+to a defconfig provided by the barebox source tree.
+If neither ``defconfig`` nor :term:`BAREBOX_CONFIG` is specified, the class
+will raise an error.
+
+The :ref:`ref-classes-barebox` class supports config fragments and internally
+includes the :ref:`ref-classes-cml1` class to provide `Kconfig
+<https://docs.kernel.org/kbuild/kconfig-language.html>`__ support for
+barebox, enabling tasks such as :ref:`ref-tasks-menuconfig` and
+:ref:`ref-tasks-diffconfig`.
+
+The generated barebox binaries are deployed to
+:term:`DEPLOY_DIR_IMAGE` as well as installed to ``BAREBOX_INSTALL_PATH``
+(``/boot`` by default) making them part of the recipe’s base package.
+This setup supports both using the barebox binaries as independent artifacts
+and installing them into a rootfs.
+:term:`BAREBOX_BINARY` can be used to select a distinct binary to deploy and
+install.
+If ``barebox`` is set as the :term:`EFI_PROVIDER`, the class will leverage
+:oe_git:`conf/image-uefi.conf </openembedded-core/tree/meta/conf/image-uefi.conf>`
+to define the default installation paths and naming conventions.
+
+The compiled-in barebox environment can be extended by adding environment files
+to the ``BAREBOX_ENV_DIR``.
+The ``BAREBOX_FIRMWARE_DIR`` variable allows you to specify the firmware blob
+search directory, enabling loading of additional firmware like TF-A or OP-TEE.
+
 .. _ref-classes-base:
 
 ``base``
diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 702a6caf8..8b996f216 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -293,6 +293,35 @@  system and gives an overview of their function and contents.
       :term:`PACKAGE_EXCLUDE` variables for related
       information.
 
+   :term:`BAREBOX_BINARY`
+      When using the :ref:`ref-classes-barebox` class, this variable allows you
+      to specify a particular binary that should be deployed and installed.
+
+      The barebox build system can build multiple barebox binaries at once.
+      By default, all built binaries will be deployed and installed under their
+      original name.
+
+      Here is an example usage of this variable::
+
+         BAREBOX_BINARY = "barebox-boundarydevices-imx6dl-nitrogen6x-1g.img"
+
+   :term:`BAREBOX_CONFIG`
+      When using the :ref:`ref-classes-barebox` class, this variable allows you
+      to specify the name of the barebox defconfig to build.
+      The name must be a defconfig file known to the barebox build environment.
+      This variable is mainly useful for generic use cases where a dedicated
+      configuration is not required.
+      The :ref:`ref-classes-barebox` class itself already sets it for some QEMU
+      machines::
+
+         BAREBOX_CONFIG:qemuarm = "multi_v7_defconfig"
+         BAREBOX_CONFIG:qemuarm64 = "multi_v8_defconfig"
+         BAREBOX_CONFIG:qemux86-64 = "efi_defconfig"
+
+      Except for these, the default value of :term:`BAREBOX_CONFIG` is empty.
+      For more information on how to provide a barebox configuration, see the
+      :ref:`ref-classes-barebox` class.
+
    :term:`BASE_LIB`
       The library directory name for the CPU or Application Binary
       Interface (ABI) tune. The :term:`BASE_LIB` applies only in the Multilib