GIC: Add API to get running priority

Document the API in separate platform interrupt controller API document.

Change-Id: If18f208e10a8a243f5c59d226fcf48e985941949
Co-authored-by: Yousuf A <yousuf.sait@arm.com>
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/docs/platform-interrupt-controller-API.rst b/docs/platform-interrupt-controller-API.rst
new file mode 100644
index 00000000..9ef2e3f6
--- /dev/null
+++ b/docs/platform-interrupt-controller-API.rst
@@ -0,0 +1,32 @@
+Platform Interrupt Controller API documentation
+===============================================
+
+.. section-numbering::
+    :suffix: .
+
+.. contents::
+
+This document lists the optional platform interrupt controller API that
+abstracts the runtime configuration and control of interrupt controller from the
+generic code. The mandatory APIs are described in the `porting guide`__.
+
+.. __: porting-guide.rst#interrupt-management-framework-in-bl31
+
+Function: unsigned int plat_ic_get_running_priority(void); [optional]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+    Argument : void
+    Return   : unsigned int
+
+This API should return the priority of the interrupt the PE is currently
+servicing. This must be be called only after an interrupt has already been
+acknowledged via. ``plat_ic_acknowledge_interrupt``.
+
+In the case of ARM standard platforms using GIC, the *Running Priority Register*
+is read to determine the priority of the interrupt.
+
+----
+
+*Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.*