1 /*
2 * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7 #include <assert.h>
8
9 #include <arch_helpers.h>
10 #include <common/debug.h>
11 #include <drivers/arm/css/css_scp.h>
12 #include <drivers/arm/css/css_scpi.h>
13 #include <plat/arm/common/plat_arm.h>
14 #include <plat/arm/css/common/css_pm.h>
15
16 /*
17 * This file implements the SCP power management functions using SCPI protocol.
18 */
19
20 /*
21 * Helper function to inform power down state to SCP.
22 */
css_scp_suspend(const struct psci_power_state * target_state)23 void css_scp_suspend(const struct psci_power_state *target_state)
24 {
25 uint32_t cluster_state = scpi_power_on;
26 uint32_t system_state = scpi_power_on;
27
28 /* Check if power down at system power domain level is requested */
29 if (css_system_pwr_state(target_state) == ARM_LOCAL_STATE_OFF)
30 system_state = scpi_power_retention;
31
32 /* Cluster is to be turned off, so disable coherency */
33 if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
34 cluster_state = scpi_power_off;
35
36 /*
37 * Ask the SCP to power down the appropriate components depending upon
38 * their state.
39 */
40 scpi_set_css_power_state(read_mpidr_el1(),
41 scpi_power_off,
42 cluster_state,
43 system_state);
44 }
45
46 /*
47 * Helper function to turn off a CPU power domain and its parent power domains
48 * if applicable. Since SCPI doesn't differentiate between OFF and suspend, we
49 * call the suspend helper here.
50 */
css_scp_off(const struct psci_power_state * target_state)51 void css_scp_off(const struct psci_power_state *target_state)
52 {
53 css_scp_suspend(target_state);
54 }
55
56 /*
57 * Helper function to turn ON a CPU power domain and its parent power domains
58 * if applicable.
59 */
css_scp_on(u_register_t mpidr)60 void css_scp_on(u_register_t mpidr)
61 {
62 /*
63 * SCP takes care of powering up parent power domains so we
64 * only need to care about level 0
65 */
66 scpi_set_css_power_state(mpidr, scpi_power_on, scpi_power_on,
67 scpi_power_on);
68 }
69
70 /*
71 * Helper function to get the power state of a power domain node as reported
72 * by the SCP.
73 */
css_scp_get_power_state(u_register_t mpidr,unsigned int power_level)74 int css_scp_get_power_state(u_register_t mpidr, unsigned int power_level)
75 {
76 int rc, element;
77 unsigned int cpu_state, cluster_state;
78
79 /*
80 * The format of 'power_level' is implementation-defined, but 0 must
81 * mean a CPU. We also allow 1 to denote the cluster
82 */
83 if (power_level != ARM_PWR_LVL0 && power_level != ARM_PWR_LVL1)
84 return PSCI_E_INVALID_PARAMS;
85
86 /* Query SCP */
87 rc = scpi_get_css_power_state(mpidr, &cpu_state, &cluster_state);
88 if (rc != 0)
89 return PSCI_E_INVALID_PARAMS;
90
91 /* Map power states of CPU and cluster to expected PSCI return codes */
92 if (power_level == ARM_PWR_LVL0) {
93 /*
94 * The CPU state returned by SCP is an 8-bit bit mask
95 * corresponding to each CPU in the cluster
96 */
97 #if ARM_PLAT_MT
98 /*
99 * The current SCPI driver only caters for single-threaded
100 * platforms. Hence we ignore the thread ID (which is always 0)
101 * for such platforms.
102 */
103 element = (mpidr >> MPIDR_AFF1_SHIFT) & MPIDR_AFFLVL_MASK;
104 #else
105 element = mpidr & MPIDR_AFFLVL_MASK;
106 #endif /* ARM_PLAT_MT */
107 return CSS_CPU_PWR_STATE(cpu_state, element) ==
108 CSS_CPU_PWR_STATE_ON ? HW_ON : HW_OFF;
109 } else {
110 assert(cluster_state == CSS_CLUSTER_PWR_STATE_ON ||
111 cluster_state == CSS_CLUSTER_PWR_STATE_OFF);
112 return cluster_state == CSS_CLUSTER_PWR_STATE_ON ? HW_ON :
113 HW_OFF;
114 }
115 }
116
117 /*
118 * Helper function to shutdown the system via SCPI.
119 */
css_scp_sys_shutdown(void)120 void __dead2 css_scp_sys_shutdown(void)
121 {
122 uint32_t response;
123
124 /*
125 * Disable GIC CPU interface to prevent pending interrupt
126 * from waking up the AP from WFI.
127 */
128 plat_arm_gic_cpuif_disable();
129
130 /* Send the power down request to the SCP */
131 response = scpi_sys_power_state(scpi_system_shutdown);
132
133 if (response != SCP_OK) {
134 ERROR("CSS System Off: SCP error %u.\n", response);
135 panic();
136 }
137 wfi();
138 ERROR("CSS System Off: operation not handled.\n");
139 panic();
140 }
141
142 /*
143 * Helper function to reset the system via SCPI.
144 */
css_scp_sys_reboot(void)145 void __dead2 css_scp_sys_reboot(void)
146 {
147 uint32_t response;
148
149 /*
150 * Disable GIC CPU interface to prevent pending interrupt
151 * from waking up the AP from WFI.
152 */
153 plat_arm_gic_cpuif_disable();
154
155 /* Send the system reset request to the SCP */
156 response = scpi_sys_power_state(scpi_system_reboot);
157
158 if (response != SCP_OK) {
159 ERROR("CSS System Reset: SCP error %u.\n", response);
160 panic();
161 }
162 wfi();
163 ERROR("CSS System Reset: operation not handled.\n");
164 panic();
165 }
166