docs(measured boot): add measured boot platform functions

Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: I411ee37cfeec32925849042689e8fdc7a26b7b13

docs/getting_started/porting-guide.rst

@@ -1199,6 +1199,25 @@ This function returns SMC_ARCH_CALL_SUCCESS if the platform supports
 the SMCCC function specified in the argument; otherwise returns
 SMC_ARCH_CALL_NOT_SUPPORTED.
 
+Function : plat_mboot_measure_image()
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    Argument : unsigned int, image_info_t *
+    Return   : void
+
+When the MEASURED_BOOT flag is enabled:
+
+-  This function measures the given image and records its measurement using
+   the measured boot backend driver.
+-  On the Arm FVP port, this function measures the given image using its
+   passed id and information and then records that measurement in the
+   Event Log buffer.
+-  This function must return 0 on success, a negative error code otherwise.
+
+When the MEASURED_BOOT flag is disabled, this function doesn't do anything.
+
 Modifications specific to a Boot Loader stage
 ---------------------------------------------
 
@@ -1450,6 +1469,42 @@ This function must return 0 on success, a non-null error code otherwise.
 The default implementation of this function asserts therefore platforms must
 override it when using the FWU feature.
 
+Function : bl1_plat_mboot_init() [optional]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    Argument : void
+    Return   : void
+
+When the MEASURED_BOOT flag is enabled:
+
+-  This function is used to initialize the backend driver(s) of measured boot.
+-  On the Arm FVP port, this function is used to initialize the Event Log
+   backend driver, and also to write header information in the Event Log buffer.
+
+When the MEASURED_BOOT flag is disabled, this function doesn't do anything.
+
+Function : bl1_plat_mboot_finish() [optional]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    Argument : void
+    Return   : void
+
+When the MEASURED_BOOT flag is enabled:
+
+-  This function is used to finalize the measured boot backend driver(s),
+   and also, set the information for the next bootloader component to
+   extend the measurement if needed.
+-  On the Arm FVP port, this function is used to pass the base address of
+   the Event Log buffer and its size to BL2 via tb_fw_config to extend the
+   Event Log buffer with the measurement of various images loaded by BL2.
+   It results in panic on error.
+
+When the MEASURED_BOOT flag is disabled, this function doesn't do anything.
+
 Boot Loader Stage 2 (BL2)
 -------------------------
 
@@ -1738,6 +1793,42 @@ Application Processor (AP) for BL2U execution to continue.
 This function returns 0 on success, a negative error code otherwise.
 This function is included if SCP_BL2U_BASE is defined.
 
+Function : bl2_plat_mboot_init() [optional]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    Argument : void
+    Return   : void
+
+When the MEASURED_BOOT flag is enabled:
+
+-  This function is used to initialize the backend driver(s) of measured boot.
+-  On the Arm FVP port, this function is used to initialize the Event Log
+   backend driver with the Event Log buffer information (base address and
+   size) received from BL1. It results in panic on error.
+
+When the MEASURED_BOOT flag is disabled, this function doesn't do anything.
+
+Function : bl2_plat_mboot_finish() [optional]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    Argument : void
+    Return   : void
+
+When the MEASURED_BOOT flag is enabled:
+
+-  This function is used to finalize the measured boot backend driver(s),
+   and also, set the information for the next bootloader component to extend
+   the measurement if needed.
+-  On the Arm FVP port, this function is used to pass the Event Log buffer
+   information (base address and size) to non-secure(BL33) and trusted OS(BL32)
+   via nt_fw and tos_fw config respectively. It results in panic on error.
+
+When the MEASURED_BOOT flag is disabled, this function doesn't do anything.
+
 Boot Loader Stage 3-1 (BL31)
 ----------------------------