1 /*
2 * Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <assert.h>
8 #include <stddef.h>
9
10 #include <arch.h>
11 #include <arch_helpers.h>
12 #include <common/bl_common.h>
13 #include <common/debug.h>
14 #include <drivers/arm/gic.h>
15 #include <lib/el3_runtime/context_mgmt.h>
16 #include <lib/el3_runtime/pubsub_events.h>
17 #include <plat/common/platform.h>
18
19 #include "psci_private.h"
20
21 /*
22 * Helper functions for the CPU level spinlocks
23 */
psci_spin_lock_cpu(unsigned int idx)24 static inline void psci_spin_lock_cpu(unsigned int idx)
25 {
26 spin_lock(&(PER_CPU_BY_INDEX(psci_cpu_pd_nodes, idx)->cpu_lock));
27 }
28
psci_spin_unlock_cpu(unsigned int idx)29 static inline void psci_spin_unlock_cpu(unsigned int idx)
30 {
31 spin_unlock(&(PER_CPU_BY_INDEX(psci_cpu_pd_nodes, idx)->cpu_lock));
32 }
33
34 /*******************************************************************************
35 * This function checks whether a cpu which has been requested to be turned on
36 * is OFF to begin with.
37 ******************************************************************************/
cpu_on_validate_state(aff_info_state_t aff_state)38 static int cpu_on_validate_state(aff_info_state_t aff_state)
39 {
40 if (aff_state == AFF_STATE_ON) {
41 return PSCI_E_ALREADY_ON;
42 }
43
44 if (aff_state == AFF_STATE_ON_PENDING) {
45 return PSCI_E_ON_PENDING;
46 }
47
48 assert(aff_state == AFF_STATE_OFF);
49 return PSCI_E_SUCCESS;
50 }
51
52 /*******************************************************************************
53 * Generic handler which is called to physically power on a cpu identified by
54 * its mpidr. It performs the generic, architectural, platform setup and state
55 * management to power on the target cpu e.g. it will ensure that
56 * enough information is stashed for it to resume execution in the non-secure
57 * security state.
58 *
59 * The state of all the relevant power domains are changed after calling the
60 * platform handler as it can return error.
61 ******************************************************************************/
psci_cpu_on_start(u_register_t target_cpu,const entry_point_info_t * ep)62 int psci_cpu_on_start(u_register_t target_cpu,
63 const entry_point_info_t *ep)
64 {
65 int rc;
66 aff_info_state_t target_aff_state;
67 unsigned int target_idx = (unsigned int)plat_core_pos_by_mpidr(target_cpu);
68
69 /*
70 * This function must only be called on platforms where the
71 * CPU_ON platform hooks have been implemented.
72 */
73 assert((psci_plat_pm_ops->pwr_domain_on != NULL) &&
74 (psci_plat_pm_ops->pwr_domain_on_finish != NULL));
75
76 /* Protect against multiple CPUs trying to turn ON the same target CPU */
77 psci_spin_lock_cpu(target_idx);
78
79 /*
80 * Generic management: Ensure that the cpu is off to be
81 * turned on.
82 * Perform cache maintanence ahead of reading the target CPU state to
83 * ensure that the data is not stale.
84 * There is a theoretical edge case where the cache may contain stale
85 * data for the target CPU data - this can occur under the following
86 * conditions:
87 * - the target CPU is in another cluster from the current
88 * - the target CPU was the last CPU to shutdown on its cluster
89 * - the cluster was removed from coherency as part of the CPU shutdown
90 *
91 * In this case the cache maintenace that was performed as part of the
92 * target CPUs shutdown was not seen by the current CPU's cluster. And
93 * so the cache may contain stale data for the target CPU.
94 */
95 flush_cpu_data_by_index(target_idx, psci_svc_cpu_data);
96 rc = cpu_on_validate_state(psci_get_aff_info_state_by_idx(target_idx));
97 if (rc != PSCI_E_SUCCESS) {
98 goto on_exit;
99 }
100
101 /*
102 * Call the cpu on handler registered by the Secure Payload Dispatcher
103 * to let it do any bookeeping. If the handler encounters an error, it's
104 * expected to assert within
105 */
106 if ((psci_spd_pm != NULL) && (psci_spd_pm->svc_on != NULL)) {
107 psci_spd_pm->svc_on(target_cpu);
108 }
109
110 /*
111 * Set the Affinity info state of the target cpu to ON_PENDING.
112 * Flush aff_info_state as it will be accessed with caches
113 * turned OFF.
114 */
115 psci_set_aff_info_state_by_idx(target_idx, AFF_STATE_ON_PENDING);
116 flush_cpu_data_by_index(target_idx, psci_svc_cpu_data);
117
118 /*
119 * The cache line invalidation by the target CPU after setting the
120 * state to OFF (see psci_do_cpu_off()), could cause the update to
121 * aff_info_state to be invalidated. Retry the update if the target
122 * CPU aff_info_state is not ON_PENDING.
123 */
124 target_aff_state = psci_get_aff_info_state_by_idx(target_idx);
125 if (target_aff_state != AFF_STATE_ON_PENDING) {
126 assert(target_aff_state == AFF_STATE_OFF);
127 psci_set_aff_info_state_by_idx(target_idx, AFF_STATE_ON_PENDING);
128 flush_cpu_data_by_index(target_idx, psci_svc_cpu_data);
129
130 assert(psci_get_aff_info_state_by_idx(target_idx) ==
131 AFF_STATE_ON_PENDING);
132 }
133
134 /*
135 * Perform generic, architecture and platform specific handling.
136 */
137 /*
138 * Plat. management: Give the platform the current state
139 * of the target cpu to allow it to perform the necessary
140 * steps to power on.
141 */
142 rc = psci_plat_pm_ops->pwr_domain_on(target_cpu);
143 assert((rc == PSCI_E_SUCCESS) || (rc == PSCI_E_INTERN_FAIL));
144
145 if (rc != PSCI_E_SUCCESS) {
146 /* Restore the state on error. */
147 psci_set_aff_info_state_by_idx(target_idx, AFF_STATE_OFF);
148 flush_cpu_data_by_index(target_idx, psci_svc_cpu_data);
149 }
150
151 on_exit:
152 psci_spin_unlock_cpu(target_idx);
153 return rc;
154 }
155
156 /*******************************************************************************
157 * The following function finish an earlier power on request. They
158 * are called by the common finisher routine in psci_common.c. The `state_info`
159 * is the psci_power_state from which this CPU has woken up from.
160 ******************************************************************************/
psci_cpu_on_finish(unsigned int cpu_idx,const psci_power_state_t * state_info)161 void psci_cpu_on_finish(unsigned int cpu_idx, const psci_power_state_t *state_info)
162 {
163 /*
164 * Plat. management: Perform the platform specific actions
165 * for this cpu e.g. enabling the gic or zeroing the mailbox
166 * register. The actual state of this cpu has already been
167 * changed.
168 */
169 psci_plat_pm_ops->pwr_domain_on_finish(state_info);
170
171 #if !(HW_ASSISTED_COHERENCY || WARMBOOT_ENABLE_DCACHE_EARLY)
172 /*
173 * Arch. management: Enable data cache and manage stack memory
174 */
175 psci_do_pwrup_cache_maintenance();
176 #endif
177
178 /*
179 * Plat. management: Perform any platform specific actions which
180 * can only be done with the cpu and the cluster guaranteed to
181 * be coherent.
182 */
183 if (psci_plat_pm_ops->pwr_domain_on_finish_late != NULL) {
184 psci_plat_pm_ops->pwr_domain_on_finish_late(state_info);
185 }
186
187 #if USE_GIC_DRIVER
188 /* GIC init after platform has had a say with MMU on */
189 gic_pcpu_init(cpu_idx);
190 gic_cpuif_enable(cpu_idx);
191 #endif /* USE_GIC_DRIVER */
192
193 /*
194 * All the platform specific actions for turning this cpu
195 * on have completed. Perform enough arch.initialization
196 * to run in the non-secure address space.
197 */
198 psci_arch_setup();
199
200 /*
201 * Lock the CPU spin lock to make sure that the context initialization
202 * is done. Since the lock is only used in this function to create
203 * a synchronization point with cpu_on_start(), it can be released
204 * immediately.
205 */
206 psci_spin_lock_cpu(cpu_idx);
207 psci_spin_unlock_cpu(cpu_idx);
208
209 /* Ensure we have been explicitly woken up by another cpu */
210 assert(psci_get_aff_info_state() == AFF_STATE_ON_PENDING);
211
212 /*
213 * Call the cpu on finish handler registered by the Secure Payload
214 * Dispatcher to let it do any bookeeping. If the handler encounters an
215 * error, it's expected to assert within
216 */
217 if ((psci_spd_pm != NULL) && (psci_spd_pm->svc_on_finish != NULL)) {
218 psci_spd_pm->svc_on_finish(0);
219 }
220 PUBLISH_EVENT(psci_cpu_on_finish);
221
222 /* Populate the mpidr field within the cpu node array */
223 /* This needs to be done only once */
224 PER_CPU_BY_INDEX(psci_cpu_pd_nodes, cpu_idx)->mpidr = read_mpidr() & MPIDR_AFFINITY_MASK;
225 }
226