[PATCH 8/8 v2] doc: uefi: Add instruction for initrd loading

[Ilias Apalodimas]

Add a description of the EFI variables needed to match a Boot####
entry with an initrd.

Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
---
 doc/uefi/uefi.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/doc/uefi/uefi.rst b/doc/uefi/uefi.rst
index dc930d924022..d8b083ffa708 100644
--- a/doc/uefi/uefi.rst
+++ b/doc/uefi/uefi.rst
@@ -229,6 +229,21 @@ UEFI variables. Booting according to these variables is possible via::
 As of U-Boot v2020.10 UEFI variables cannot be set at runtime. The U-Boot
 command 'efidebug' can be used to set the variables.
 
+Initrd with the boot manager
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Kernel versions >= 5.6 can use EFI_LOAD_FILE2_PROTOCOL to load an initramfs.
+When U-Boot is configured with CONFIG_EFI_LOAD_FILE2_INITRD=y the boot manager
+will install the protocol, if an EFI variable matching the BootCurrent value
+is found and contains a valid file path. The EFI variable name is 'Initrd####'
+and the file path format is '<device> <partition> <filename>'.
+
+This allows users to pair a kernel with a specific initramfs.
+
+Example:
+Boot0010 will search for Initrd0010 and try to install the protocol with
+the file path specified in Initrd0010.
+
 Executing the built in hello world application
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-- 
2.30.0