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
diff --git a/lib/psci/psci_off.c b/lib/psci/psci_off.c
new file mode 100644
index 0000000..471141d
--- /dev/null
+++ b/lib/psci/psci_off.c
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <arch.h>
+#include <arch_helpers.h>
+#include <assert.h>
+#include <debug.h>
+#include <platform.h>
+#include <string.h>
+#include "psci_private.h"
+
+/******************************************************************************
+ * Construct the psci_power_state to request power OFF at all power levels.
+ ******************************************************************************/
+static void psci_set_power_off_state(psci_power_state_t *state_info)
+{
+	int lvl;
+
+	for (lvl = PSCI_CPU_PWR_LVL; lvl <= PLAT_MAX_PWR_LVL; lvl++)
+		state_info->pwr_domain_state[lvl] = PLAT_MAX_OFF_STATE;
+}
+
+/******************************************************************************
+ * Top level handler which is called when a cpu wants to power itself down.
+ * It's assumed that along with turning the cpu power domain off, power
+ * domains at higher levels will be turned off as far as possible. It finds
+ * the highest level where a domain has to be powered off by traversing the
+ * node information and then performs generic, architectural, platform setup
+ * and state management required to turn OFF that power domain and domains
+ * below it. e.g. For a cpu that's to be powered OFF, it could mean programming
+ * the power controller whereas for a cluster that's to be powered off, it will
+ * call the platform specific code which will disable coherency at the
+ * interconnect level if the cpu is the last in the cluster and also the
+ * program the power controller.
+ ******************************************************************************/
+int psci_do_cpu_off(unsigned int end_pwrlvl)
+{
+	int rc = PSCI_E_SUCCESS, idx = plat_my_core_pos();
+	psci_power_state_t state_info;
+
+	/*
+	 * This function must only be called on platforms where the
+	 * CPU_OFF platform hooks have been implemented.
+	 */
+	assert(psci_plat_pm_ops->pwr_domain_off);
+
+	/*
+	 * This function acquires the lock corresponding to each power
+	 * level so that by the time all locks are taken, the system topology
+	 * is snapshot and state management can be done safely.
+	 */
+	psci_acquire_pwr_domain_locks(end_pwrlvl,
+				      idx);
+
+	/*
+	 * Call the cpu off handler registered by the Secure Payload Dispatcher
+	 * to let it do any bookkeeping. Assume that the SPD always reports an
+	 * E_DENIED error if SP refuse to power down
+	 */
+	if (psci_spd_pm && psci_spd_pm->svc_off) {
+		rc = psci_spd_pm->svc_off(0);
+		if (rc)
+			goto exit;
+	}
+
+	/* Construct the psci_power_state for CPU_OFF */
+	psci_set_power_off_state(&state_info);
+
+	/*
+	 * This function is passed the requested state info and
+	 * it returns the negotiated state info for each power level upto
+	 * the end level specified.
+	 */
+	psci_do_state_coordination(end_pwrlvl, &state_info);
+
+#if ENABLE_PSCI_STAT
+	/* Update the last cpu for each level till end_pwrlvl */
+	psci_stats_update_pwr_down(end_pwrlvl, &state_info);
+#endif
+
+	/*
+	 * Arch. management. Perform the necessary steps to flush all
+	 * cpu caches.
+	 */
+	psci_do_pwrdown_cache_maintenance(psci_find_max_off_lvl(&state_info));
+
+	/*
+	 * Plat. management: Perform platform specific actions to turn this
+	 * cpu off e.g. exit cpu coherency, program the power controller etc.
+	 */
+	psci_plat_pm_ops->pwr_domain_off(&state_info);
+
+#if ENABLE_PSCI_STAT
+	/*
+	 * Capture time-stamp while entering low power state.
+	 * No cache maintenance needed because caches are off
+	 * and writes are direct to main memory.
+	 */
+	PMF_CAPTURE_TIMESTAMP(psci_svc, PSCI_STAT_ID_ENTER_LOW_PWR,
+		PMF_NO_CACHE_MAINT);
+#endif
+
+exit:
+	/*
+	 * Release the locks corresponding to each power level in the
+	 * reverse order to which they were acquired.
+	 */
+	psci_release_pwr_domain_locks(end_pwrlvl,
+				      idx);
+
+	/*
+	 * Check if all actions needed to safely power down this cpu have
+	 * successfully completed.
+	 */
+	if (rc == PSCI_E_SUCCESS) {
+		/*
+		 * Set the affinity info state to OFF. This writes directly to
+		 * main memory as caches are disabled, so cache maintenance is
+		 * required to ensure that later cached reads of aff_info_state
+		 * return AFF_STATE_OFF.  A dsbish() ensures ordering of the
+		 * update to the affinity info state prior to cache line
+		 * invalidation.
+		 */
+		flush_cpu_data(psci_svc_cpu_data.aff_info_state);
+		psci_set_aff_info_state(AFF_STATE_OFF);
+		dsbish();
+		inv_cpu_data(psci_svc_cpu_data.aff_info_state);
+
+		if (psci_plat_pm_ops->pwr_domain_pwr_down_wfi) {
+			/* This function must not return */
+			psci_plat_pm_ops->pwr_domain_pwr_down_wfi(&state_info);
+		} else {
+			/*
+			 * Enter a wfi loop which will allow the power
+			 * controller to physically power down this cpu.
+			 */
+			psci_power_down_wfi();
+		}
+	}
+
+	return rc;
+}