doc: man-page for optee commands

Provide a man-page for the optee command.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
(cherry picked from commit 20e1c18721)

doc/usage/cmd/optee.rst

@@ -0,0 +1,70 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. index::
+   single: optee (command)
+
+optee command
+=============
+
+Synopsis
+--------
+
+::
+
+    optee hello
+    optee hello <value>
+
+Description
+-----------
+
+This is an OP-TEE sanity test which invokes the "Hello World"
+Trusted Application (TA). The TA does two things:
+- It prints debug and information messages to the secure console (if logging is enabled)
+- It increments the integer value passed as a parameter and returns it
+
+
+value
+	Integer value that the TA is expected to increment and return.
+	The default value is 0.
+
+To enable the OP-TEE Hello World example please refer
+https://optee.readthedocs.io/en/latest/building/gits/optee_examples/optee_examples.html
+
+Examples
+--------
+
+::
+
+	==> optee hello
+	D/TA:  TA_CreateEntryPoint:39 has been called
+	I/TA: Hello World!
+	Value before: 0x0
+	Calling TA
+	D/TA:  inc_value:105 has been called
+	I/TA: Got value: 0 from NW
+	I/TA: Increase value to: 1
+	Value after: 0x1
+	I/TA: Goodbye!
+	D/TA:  TA_DestroyEntryPoint:50 has been called
+
+	==> optee hello 74
+	D/TA:  TA_CreateEntryPoint:39 has been called
+	I/TA: Hello World!
+	Value before: 0x74
+	Calling TA
+	D/TA:  inc_value:105 has been called
+	I/TA: Got value: 116 from NW
+	I/TA: Increase value to: 117
+	Value after: 0x75
+	I/TA: Goodbye!
+	D/TA:  TA_DestroyEntryPoint:50 has been called
+
+Configuration
+-------------
+
+The optee command is enabled by CONFIG_OPTEE=y and CONFIG_CMD_OPTEE=y.
+
+Return value
+------------
+
+The return value $? is 0 (true) if the command succeeds, 1 (false) otherwise.

doc/usage/index.rst

@@ -106,6 +106,7 @@ Shell commands
    cmd/mtest
    cmd/mtrr
    cmd/mv
+   cmd/optee
    cmd/panic
    cmd/part
    cmd/part_find