[PATCH v2] ref-manual: uboot-sign: Add how to enable ATF, TEE and User defined snippet ITS for U-Boot FIT image

[Jamin Lin <jamin_lin@aspeedtech.com>]

Add how to enable ATF, TEE and User defined ITS for U-Boot FIT image generation.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
---
 documentation/ref-manual/classes.rst   |  8 +++
 documentation/ref-manual/variables.rst | 72 ++++++++++++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/documentation/ref-manual/classes.rst b/documentation/ref-manual/classes.rst
index b93279ff6..d1669ed87 100644
--- a/documentation/ref-manual/classes.rst
+++ b/documentation/ref-manual/classes.rst
@@ -3401,6 +3401,14 @@ The variables used by this class are:
 -  :term:`UBOOT_FITIMAGE_ENABLE`: enable the generation of a U-Boot FIT image.
 -  :term:`UBOOT_MKIMAGE_DTCOPTS`: DTC options for U-Boot ``mkimage`` when
    rebuilding the FIT image containing the kernel.
+-  :term:`UBOOT_FIT_ARM_TRUSTED_FIRMWARE`: enable the ARM Trusted Firmware (ATF) image.
+-  :term:`UBOOT_FIT_ARM_TRUSTED_FIRMWARE_IMAGE`: specifie the path to the ATF image.
+-  :term:`UBOOT_FIT_TEE`: enable the Trusted Execution Environment (TEE) image.
+-  :term:`UBOOT_FIT_TEE_IMAGE`: specifie the path to the TEE image.
+-  :term:`UBOOT_FIT_USER_SETTINGS`: add a user-specific snippet to the ITS. Users can
+   include their custom ITS snippet in this variable.
+-  :term:`UBOOT_FIT_CONF_USER_LOADABLES`: adds a user-defined image to the loadable
+   property of the configuration node. It should be a comma-separated list of strings.
 
 See U-Boot's documentation for details about `verified boot
 <https://source.denx.de/u-boot/u-boot/-/blob/master/doc/uImage.FIT/verified-boot.txt>`__
diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 60984cc8f..dbbaac56d 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -9884,6 +9884,78 @@ system and gives an overview of their function and contents.
 
       See the :ref:`ref-classes-uboot-sign` class for details.
 
+   :term:`UBOOT_FIT_ARM_TRUSTED_FIRMWARE`
+      ARM Trusted Firmware (ATF) is a reference implementation of secure world
+      software for Arm A-Profile architectures (Armv8-A and Armv7-A), including
+      an Exception Level 3 (EL3) Secure Monitor. This variable enables the
+      generation of a U-Boot FIT image with an ATF image.
+
+      Its default value is "0", so set it to "1" to enable this functionality::
+
+         UBOOT_FIT_ARM_TRUSTED_FIRMWARE = "1"
+
+   :term:`UBOOT_FIT_ARM_TRUSTED_FIRMWARE_IMAGE`
+      Specifies the path to the ATF image. Its default value is "bl31.bin"
+
+         UBOOT_FIT_ARM_TRUSTED_FIRMWARE_IMAGE ?= "bl31.bin"
+
+   :term:`UBOOT_FIT_TEE`
+      A Trusted Execution Environment (TEE) is a secure environment for executing
+      code, ensuring high levels of trust in asset management within the
+      surrounding system. This variable enables the generation of a U-Boot FIT
+      image with a TEE image.
+
+      Its default value is "0", so set it to "1" to enable this functionality::
+
+         UBOOT_FIT_TEE = "1"
+
+   :term:`UBOOT_FIT_TEE_IMAGE`
+      Specifies the path to the TEE image. Its default value is "tee-raw.bin"::
+
+         UBOOT_FIT_TEE_IMAGE ?= "tee-raw.bin"
+
+   :term:`UBOOT_FIT_USER_SETTINGS`
+      Add a user-specific snippet to the ITS. Users can include their custom ITS
+      snippet in this variable.
+
+      Ex::
+
+         UBOOT_FIT_FWA_ITS = '\
+             fwa {\n\
+                 description = \"FW A\";\n\
+                 data = /incbin/(\"fwa.bin\");\n\
+                 type = \"fwtype\";\n\
+                 arch = \"fwarch\";\n\
+                 os = \"fwos\";\n\
+                 load = <0xb2000000>;\n\
+                 entry = <0xb2000000>;\n\
+                 compression = \"none\";\n\
+             };\n\
+         '
+
+         UBOOT_FIT_USER_SETTINGS = "${UBOOT_FIT_FWA_ITS}"
+
+       The generated Image Tree Source (ITS):
+
+         fwa {
+             description = "FW A";
+             data = /incbin/("fwa.bin");
+             type = "fwtype";
+             arch = "fwarch";
+             os = "fwos";
+             load = <0xb2000000>;
+             entry = <0xb2000000>;
+             compression = "none";
+         };
+
+   :term:`UBOOT_FIT_CONF_USER_LOADABLES`
+      Adds a user-defined image to the loadable property of the configuration node.
+      It should be a comma-separated list of strings.
+
+      Ex::
+
+         UBOOT_FIT_CONF_USER_LOADABLES = '\"fwa\", \"fwb\"'
+
    :term:`UBOOT_LOADADDRESS`
       Specifies the load address for the U-Boot image. During U-Boot image
       creation, the :term:`UBOOT_LOADADDRESS` variable is passed as a
-- 
2.34.1