1 files changed, 233 insertions, 0 deletions
diff --git a/lib/psci/psci_on.c b/lib/psci/psci_on.c
new file mode 100644
index 0000000..c70b377
--- /dev/null
+++ b/lib/psci/psci_on.c
@@ -0,0 +1,233 @@
+/*
+ * Copyright (c) 2013-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stddef.h>
+
+#include <arch.h>
+#include <arch_helpers.h>
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <lib/el3_runtime/context_mgmt.h>
+#include <lib/el3_runtime/pubsub_events.h>
+#include <plat/common/platform.h>
+
+#include "psci_private.h"
+
+/*
+ * Helper functions for the CPU level spinlocks
+ */
+static inline void psci_spin_lock_cpu(unsigned int idx)
+{
+	spin_lock(&psci_cpu_pd_nodes[idx].cpu_lock);
+}
+
+static inline void psci_spin_unlock_cpu(unsigned int idx)
+{
+	spin_unlock(&psci_cpu_pd_nodes[idx].cpu_lock);
+}
+
+/*******************************************************************************
+ * This function checks whether a cpu which has been requested to be turned on
+ * is OFF to begin with.
+ ******************************************************************************/
+static int cpu_on_validate_state(aff_info_state_t aff_state)
+{
+	if (aff_state == AFF_STATE_ON)
+		return PSCI_E_ALREADY_ON;
+
+	if (aff_state == AFF_STATE_ON_PENDING)
+		return PSCI_E_ON_PENDING;
+
+	assert(aff_state == AFF_STATE_OFF);
+	return PSCI_E_SUCCESS;
+}
+
+/*******************************************************************************
+ * Generic handler which is called to physically power on a cpu identified by
+ * its mpidr. It performs the generic, architectural, platform setup and state
+ * management to power on the target cpu e.g. it will ensure that
+ * enough information is stashed for it to resume execution in the non-secure
+ * security state.
+ *
+ * The state of all the relevant power domains are changed after calling the
+ * platform handler as it can return error.
+ ******************************************************************************/
+int psci_cpu_on_start(u_register_t target_cpu,
+		      const entry_point_info_t *ep)
+{
+	int rc;
+	aff_info_state_t target_aff_state;
+	int ret = plat_core_pos_by_mpidr(target_cpu);
+	unsigned int target_idx = (unsigned int)ret;
+
+	/* Calling function must supply valid input arguments */
+	assert(ret >= 0);
+	assert(ep != NULL);
+
+
+	/*
+	 * This function must only be called on platforms where the
+	 * CPU_ON platform hooks have been implemented.
+	 */
+	assert((psci_plat_pm_ops->pwr_domain_on != NULL) &&
+	       (psci_plat_pm_ops->pwr_domain_on_finish != NULL));
+
+	/* Protect against multiple CPUs trying to turn ON the same target CPU */
+	psci_spin_lock_cpu(target_idx);
+
+	/*
+	 * Generic management: Ensure that the cpu is off to be
+	 * turned on.
+	 * Perform cache maintanence ahead of reading the target CPU state to
+	 * ensure that the data is not stale.
+	 * There is a theoretical edge case where the cache may contain stale
+	 * data for the target CPU data - this can occur under the following
+	 * conditions:
+	 * - the target CPU is in another cluster from the current
+	 * - the target CPU was the last CPU to shutdown on its cluster
+	 * - the cluster was removed from coherency as part of the CPU shutdown
+	 *
+	 * In this case the cache maintenace that was performed as part of the
+	 * target CPUs shutdown was not seen by the current CPU's cluster. And
+	 * so the cache may contain stale data for the target CPU.
+	 */
+	flush_cpu_data_by_index(target_idx,
+				psci_svc_cpu_data.aff_info_state);
+	rc = cpu_on_validate_state(psci_get_aff_info_state_by_idx(target_idx));
+	if (rc != PSCI_E_SUCCESS)
+		goto exit;
+
+	/*
+	 * Call the cpu on handler registered by the Secure Payload Dispatcher
+	 * to let it do any bookeeping. If the handler encounters an error, it's
+	 * expected to assert within
+	 */
+	if ((psci_spd_pm != NULL) && (psci_spd_pm->svc_on != NULL))
+		psci_spd_pm->svc_on(target_cpu);
+
+	/*
+	 * Set the Affinity info state of the target cpu to ON_PENDING.
+	 * Flush aff_info_state as it will be accessed with caches
+	 * turned OFF.
+	 */
+	psci_set_aff_info_state_by_idx(target_idx, AFF_STATE_ON_PENDING);
+	flush_cpu_data_by_index(target_idx,
+				psci_svc_cpu_data.aff_info_state);
+
+	/*
+	 * The cache line invalidation by the target CPU after setting the
+	 * state to OFF (see psci_do_cpu_off()), could cause the update to
+	 * aff_info_state to be invalidated. Retry the update if the target
+	 * CPU aff_info_state is not ON_PENDING.
+	 */
+	target_aff_state = psci_get_aff_info_state_by_idx(target_idx);
+	if (target_aff_state != AFF_STATE_ON_PENDING) {
+		assert(target_aff_state == AFF_STATE_OFF);
+		psci_set_aff_info_state_by_idx(target_idx, AFF_STATE_ON_PENDING);
+		flush_cpu_data_by_index(target_idx,
+					psci_svc_cpu_data.aff_info_state);
+
+		assert(psci_get_aff_info_state_by_idx(target_idx) ==
+		       AFF_STATE_ON_PENDING);
+	}
+
+	/*
+	 * Perform generic, architecture and platform specific handling.
+	 */
+	/*
+	 * Plat. management: Give the platform the current state
+	 * of the target cpu to allow it to perform the necessary
+	 * steps to power on.
+	 */
+	rc = psci_plat_pm_ops->pwr_domain_on(target_cpu);
+	assert((rc == PSCI_E_SUCCESS) || (rc == PSCI_E_INTERN_FAIL));
+
+	if (rc == PSCI_E_SUCCESS)
+		/* Store the re-entry information for the non-secure world. */
+		cm_init_context_by_index(target_idx, ep);
+	else {
+		/* Restore the state on error. */
+		psci_set_aff_info_state_by_idx(target_idx, AFF_STATE_OFF);
+		flush_cpu_data_by_index(target_idx,
+					psci_svc_cpu_data.aff_info_state);
+	}
+
+exit:
+	psci_spin_unlock_cpu(target_idx);
+	return rc;
+}
+
+/*******************************************************************************
+ * The following function finish an earlier power on request. They
+ * are called by the common finisher routine in psci_common.c. The `state_info`
+ * is the psci_power_state from which this CPU has woken up from.
+ ******************************************************************************/
+void psci_cpu_on_finish(unsigned int cpu_idx, const psci_power_state_t *state_info)
+{
+	/*
+	 * Plat. management: Perform the platform specific actions
+	 * for this cpu e.g. enabling the gic or zeroing the mailbox
+	 * register. The actual state of this cpu has already been
+	 * changed.
+	 */
+	psci_plat_pm_ops->pwr_domain_on_finish(state_info);
+
+#if !(HW_ASSISTED_COHERENCY || WARMBOOT_ENABLE_DCACHE_EARLY)
+	/*
+	 * Arch. management: Enable data cache and manage stack memory
+	 */
+	psci_do_pwrup_cache_maintenance();
+#endif
+
+	/*
+	 * Plat. management: Perform any platform specific actions which
+	 * can only be done with the cpu and the cluster guaranteed to
+	 * be coherent.
+	 */
+	if (psci_plat_pm_ops->pwr_domain_on_finish_late != NULL)
+		psci_plat_pm_ops->pwr_domain_on_finish_late(state_info);
+
+	/*
+	 * All the platform specific actions for turning this cpu
+	 * on have completed. Perform enough arch.initialization
+	 * to run in the non-secure address space.
+	 */
+	psci_arch_setup();
+
+	/*
+	 * Lock the CPU spin lock to make sure that the context initialization
+	 * is done. Since the lock is only used in this function to create
+	 * a synchronization point with cpu_on_start(), it can be released
+	 * immediately.
+	 */
+	psci_spin_lock_cpu(cpu_idx);
+	psci_spin_unlock_cpu(cpu_idx);
+
+	/* Ensure we have been explicitly woken up by another cpu */
+	assert(psci_get_aff_info_state() == AFF_STATE_ON_PENDING);
+
+	/*
+	 * Call the cpu on finish handler registered by the Secure Payload
+	 * Dispatcher to let it do any bookeeping. If the handler encounters an
+	 * error, it's expected to assert within
+	 */
+	if ((psci_spd_pm != NULL) && (psci_spd_pm->svc_on_finish != NULL))
+		psci_spd_pm->svc_on_finish(0);
+
+	PUBLISH_EVENT(psci_cpu_on_finish);
+
+	/* Populate the mpidr field within the cpu node array */
+	/* This needs to be done only once */
+	psci_cpu_pd_nodes[cpu_idx].mpidr = read_mpidr() & MPIDR_AFFINITY_MASK;
+
+	/*
+	 * Generic management: Now we just need to retrieve the
+	 * information that we had stashed away during the cpu_on
+	 * call to set this cpu on its way.
+	 */
+	cm_prepare_el3_exit_ns();
+}