Introduce `el3_runtime` and `PSCI` libraries

This patch moves the PSCI services and BL31 frameworks like context
management and per-cpu data into new library components `PSCI` and
`el3_runtime` respectively. This enables PSCI to be built independently from
BL31. A new `psci_lib.mk` makefile is introduced which adds the relevant
PSCI library sources and gets included by `bl31.mk`. Other changes which
are done as part of this patch are:

* The runtime services framework is now moved to the `common/` folder to
  enable reuse.
* The `asm_macros.S` and `assert_macros.S` helpers are moved to architecture
  specific folder.
* The `plat_psci_common.c` is moved from the `plat/common/aarch64/` folder
  to `plat/common` folder. The original file location now has a stub which
  just includes the file from new location to maintain platform compatibility.

Most of the changes wouldn't affect platform builds as they just involve
changes to the generic bl1.mk and bl31.mk makefiles.

NOTE: THE `plat_psci_common.c` FILE HAS MOVED LOCATION AND THE STUB FILE AT
THE ORIGINAL LOCATION IS NOW DEPRECATED. PLATFORMS SHOULD MODIFY THEIR
MAKEFILES TO INCLUDE THE FILE FROM THE NEW LOCATION.

Change-Id: I6bd87d5b59424995c6a65ef8076d4fda91ad5e86

2 files changed, 7 insertions, 8 deletions

diff --git a/docs/firmware-design.md b/docs/firmware-design.md
index b99a2838..d9f9ff02 100644
--- a/docs/firmware-design.md
+++ b/docs/firmware-design.md
@@ -1779,10 +1779,11 @@ following categories (present as directories in the source code):
     the platform.
 *   **Common code.** This is platform and architecture agnostic code.
 *   **Library code.** This code comprises of functionality commonly used by all
-    other code.
+    other code. The PSCI implementation and other EL3 runtime frameworks reside
+    as Library components.
 *   **Stage specific.** Code specific to a boot stage.
 *   **Drivers.**
-*   **Services.** EL3 runtime services, e.g. PSCI or SPD. Specific SPD services
+*   **Services.** EL3 runtime services (eg: SPD). Specific SPD services
     reside in the `services/spd` directory (e.g. `services/spd/tspd`).
 
 Each boot loader stage uses code from one or more of the above mentioned
diff --git a/docs/rt-svc-writers-guide.md b/docs/rt-svc-writers-guide.md
index 856e8feb..7fe71851 100644
--- a/docs/rt-svc-writers-guide.md
+++ b/docs/rt-svc-writers-guide.md
@@ -95,8 +95,7 @@ handler will be responsible for all SMC Functions within a given service type.
 
 ARM Trusted Firmware has a [`services`] directory in the source tree under which
 each owning entity can place the implementation of its runtime service.  The
-[PSCI] implementation is located here in the [`services/std_svc/psci`]
-directory.
+[PSCI] implementation is located here in the [`lib/psci`] directory.
 
 Runtime service sources will need to include the [`runtime_svc.h`] header file.
 
@@ -299,12 +298,11 @@ provide this information....
 _Copyright (c) 2014-2015, ARM Limited and Contributors. All rights reserved._
 
 
-[Firmware Design]:  ./firmware-design.md
-
+[Firmware Design]:          ./firmware-design.md
 [`services`]:               ../services
-[`services/std_svc/psci`]:  ../services/std_svc/psci
+[`lib/psci`]:               ../lib/psci
 [`std_svc_setup.c`]:        ../services/std_svc/std_svc_setup.c
-[`runtime_svc.h`]:          ../include/bl31/runtime_svc.h
+[`runtime_svc.h`]:          ../include/common/runtime_svc.h
 [`smcc_helpers.h`]:          ../include/common/smcc_helpers.h
 [PSCI]:                     http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf "Power State Coordination Interface PDD (ARM DEN 0022C)"
 [SMCCC]:                    http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html "SMC Calling Convention PDD (ARM DEN 0028A)"