1*54fd6939SJiyong ParkPlatform Compatibility Policy 2*54fd6939SJiyong Park============================= 3*54fd6939SJiyong Park 4*54fd6939SJiyong ParkIntroduction 5*54fd6939SJiyong Park------------ 6*54fd6939SJiyong Park 7*54fd6939SJiyong ParkThis document clarifies the project's policy around compatibility for upstream 8*54fd6939SJiyong Parkplatforms. 9*54fd6939SJiyong Park 10*54fd6939SJiyong ParkPlatform compatibility policy 11*54fd6939SJiyong Park----------------------------- 12*54fd6939SJiyong Park 13*54fd6939SJiyong ParkPlatform compatibility is mainly affected by changes to Platform APIs (as 14*54fd6939SJiyong Parkdocumented in the :ref:`Porting Guide`), driver APIs (like the GICv3 drivers) or 15*54fd6939SJiyong Parklibrary interfaces (like xlat_table library). The project will try to maintain 16*54fd6939SJiyong Parkcompatibility for upstream platforms. Due to evolving requirements and 17*54fd6939SJiyong Parkenhancements, there might be changes affecting platform compatibility which 18*54fd6939SJiyong Parkmeans the previous interface needs to be deprecated and a new interface 19*54fd6939SJiyong Parkintroduced to replace it. In case the migration to the new interface is trivial, 20*54fd6939SJiyong Parkthe contributor of the change is expected to make good effort to migrate the 21*54fd6939SJiyong Parkupstream platforms to the new interface. 22*54fd6939SJiyong Park 23*54fd6939SJiyong ParkThe deprecated interfaces are listed inside :ref:`Release Processes` as well as 24*54fd6939SJiyong Parkthe release after which each one will be removed. When an interface is 25*54fd6939SJiyong Parkdeprecated, the page must be updated to indicate the release after which the 26*54fd6939SJiyong Parkinterface will be removed. This must be at least 1 full release cycle in future. 27*54fd6939SJiyong ParkFor non-trivial interface changes, an email should be sent out to the `TF-A 28*54fd6939SJiyong Parkpublic mailing list`_ to notify platforms that they should migrate away from the 29*54fd6939SJiyong Parkdeprecated interfaces. Platforms are expected to migrate before the removal of 30*54fd6939SJiyong Parkthe deprecated interface. 31*54fd6939SJiyong Park 32*54fd6939SJiyong Park-------------- 33*54fd6939SJiyong Park 34*54fd6939SJiyong Park*Copyright (c) 2018-2019, Arm Limited and Contributors. All rights reserved.* 35*54fd6939SJiyong Park 36*54fd6939SJiyong Park.. _TF-A public mailing list: https://lists.trustedfirmware.org/mailman/listinfo/tf-a 37