doc: add bootelf command documentation

Signed-off-by: Maxim Moskalets <maximmosk4@gmail.com>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

doc/usage/cmd/bootelf.rst

@@ -0,0 +1,61 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+.. Copyright 2024, Maxim Moskalets <maximmosk4@gmail.com>
+
+.. index::
+   single: bootelf (command)
+
+bootelf command
+===============
+
+Synopsis
+--------
+
+::
+
+    bootelf [-p|-s] [-d <fdt_addr>] [<image_addr> [<arg>]...]
+
+Description
+-----------
+
+The *bootelf* command is used to launch a ELF binary at *image_addr*. If
+*image_addr* is not specified, the bootelf command will try to find image in
+*image_load_addr* variable (*CONFIG\_SYS\_LOAD\_ADDR* by default).
+
+Args after *image_addr* will be passed to application in common *argc*, *argv*
+format.
+
+A command sequence to run a ELF image using FDT might look like
+
+::
+
+    load mmc 0:1 ${loadaddr} /kernel.elf
+    load mmc 0:1 ${fdt_addr_r} /soc-board.dtb
+    bootelf -d ${fdt_addr_r} ${loadaddr} ${loadaddr}
+
+image_addr
+    Address of the ELF binary.
+
+fdt_addr
+    Address of the device-tree. This argument in only needed if bootable
+    application uses FDT that requires additional setup (like /memory node).
+
+arg
+    Any text arguments for bootable application. This is usually the address
+    of the device-tree.
+
+Flags:
+
+-p
+    Load ELF image via program headers.
+
+-s
+    Load ELF image via section headers.
+
+-d
+    Setup FDT by address.
+
+Configuration
+-------------
+
+The bootelf command is only available if CONFIG_CMD_ELF=y. FDT setup by flag -d
+need CONFIG_CMD_ELF_FDT_SETUP=y.

doc/usage/index.rst

@@ -33,6 +33,7 @@ Shell commands
    cmd/bootd
    cmd/bootdev
    cmd/bootefi
+   cmd/bootelf
    cmd/bootflow
    cmd/booti
    cmd/bootm