efi: doc: Add documentation for efidebug command in the app

Mention the efidebug command specifically the EFI-app documentaion, to
highlight its usefulness.

Series-to: concept
Series-cc: heinrich
Cover-letter:
efi: Move towards the EFI app booting EFI applications
This series adds various new features to the EFI app, mostly by moving
code over from the EFI loader implementation.

In particular it adds support for the efidebug command (with only a
subset of subcommands so far).

The main approach is to make use of the system table (for both the app
and the loader) instead of directly calling EFI-loader code.

It also includes a few fixes, which likely have no effect but will help
to avoid confusion in future.
END

Signed-off-by: Simon Glass <sjg@chromium.org>
Series-version: 2
Series-changes: 2
- Mention the 'dh' subcommand
- Mention that 'order' allows the boot order to be changed
- Mention the eficonfig command and the underlying UEFI firmware
Series-links: 2:10

doc/develop/uefi/u-boot_on_efi.rst

@@ -143,6 +143,30 @@ enough) should be straightforward.
 
 Use the 'reset' command to get back to EFI.
 
+EFI Debugging Commands
+~~~~~~~~~~~~~~~~~~~~~~
+When running as an EFI application, U-Boot provides access to the 'efidebug'
+command, which offers a subset of functionality useful for debugging and
+inspecting the UEFI environment. This command allows you to:
+
+* Display memory maps with 'efidebug memmap'
+* Show EFI system tables with 'efidebug show tables'
+* Show EFI handles with 'efidebug dh'
+* Manage boot options with 'efidebug boot' subcommands:
+
+  - dump - Display current boot options
+  - add - Add new boot options
+  - rm - Remove boot options
+  - order - Display and modify the boot order
+
+This command uses the EFI system table and runtime services to provide this
+functionality, so it can help with understanding and debugging UEFI
+environments. See the :doc:`/usage/cmd/efidebug` for more information.
+
+See also the :doc:`/usage/cmd/eficonfig` for controlling the boot order. The
+underlying UEFI firmware typically provides an easier way to manage boot
+options.
+
 EFI Payload
 ~~~~~~~~~~~
 The payload approach is a different kettle of fish. It works by building