Docs: Update design guide for dynamic config

This patch updates the `firmware-design.rst` document for
changes in ARM-TF for supporting dynamic configuration features
as presented in `Secure Firmware BoF SFO'17`[1].

The patch also updates the user-guide for 2 build options for FVP
pertaining to dynamic config.

[1] https://www.slideshare.net/linaroorg/bof-device-tree-and-secure-firmware-bof-sfo17310

Change-Id: Ic099cf41e7f1a98718c39854e6286d884011d445
Signed-off-by: Soby Mathew <soby.mathew@arm.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/docs/user-guide.rst b/docs/user-guide.rst
index 9e23711aa..ebca4ecde 100644
--- a/docs/user-guide.rst
+++ b/docs/user-guide.rst
@@ -776,6 +776,19 @@ ARM FVP platform specific build options
    for functions that wait for an arbitrary time length (udelay and mdelay).
    The default value is 0.
 
+-  ``FVP_HW_CONFIG_DTS`` : Specify the path to the DTS file to be compiled
+   to DTB and packaged in FIP as the HW_CONFIG. See `Firmware Design`_ for
+   details on HW_CONFIG. By default, this is initialized to a sensible DTS
+   file in ``fdts/`` folder depending on other build options. But some cases,
+   like shifted affinity format for MPIDR, cannot be detected at build time
+   and this option is needed to specify the appropriate DTS file.
+
+-  ``FVP_HW_CONFIG`` : Specify the path to the HW_CONFIG blob to be packaged in
+   FIP. See `Firmware Design`_ for details on HW_CONFIG. This option is
+   similar to the ``FVP_HW_CONFIG_DTS`` option, but it directly specifies the
+   HW_CONFIG blob instead of the DTS file. This option is useful to override
+   the default HW_CONFIG selected by the build system.
+
 Debugging options
 ~~~~~~~~~~~~~~~~~