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/*
* 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;
unsigned int target_idx = (unsigned int)plat_core_pos_by_mpidr(target_cpu);
/*
* 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;
}
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