1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License version 2 as 4 * published by the Free Software Foundation. 5 * 6 * This program is distributed in the hope that it will be useful, 7 * but WITHOUT ANY WARRANTY; without even the implied warranty of 8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 9 * GNU General Public License for more details. 10 * 11 * Copyright (C) 2013 ARM Limited 12 * 13 * Author: Will Deacon <will.deacon@arm.com> 14 */ 15 16 #define pr_fmt(fmt) "psci: " fmt 17 18 #include <linux/init.h> 19 #include <linux/of.h> 20 #include <linux/smp.h> 21 #include <linux/delay.h> 22 #include <linux/psci.h> 23 #include <linux/slab.h> 24 25 #include <uapi/linux/psci.h> 26 27 #include <asm/compiler.h> 28 #include <asm/cpu_ops.h> 29 #include <asm/errno.h> 30 #include <asm/smp_plat.h> 31 #include <asm/suspend.h> 32 33 static bool psci_power_state_loses_context(u32 state) 34 { 35 return state & PSCI_0_2_POWER_STATE_TYPE_MASK; 36 } 37 38 static bool psci_power_state_is_valid(u32 state) 39 { 40 const u32 valid_mask = PSCI_0_2_POWER_STATE_ID_MASK | 41 PSCI_0_2_POWER_STATE_TYPE_MASK | 42 PSCI_0_2_POWER_STATE_AFFL_MASK; 43 44 return !(state & ~valid_mask); 45 } 46 47 static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state); 48 49 static int __maybe_unused cpu_psci_cpu_init_idle(unsigned int cpu) 50 { 51 int i, ret, count = 0; 52 u32 *psci_states; 53 struct device_node *state_node, *cpu_node; 54 55 cpu_node = of_get_cpu_node(cpu, NULL); 56 if (!cpu_node) 57 return -ENODEV; 58 59 /* 60 * If the PSCI cpu_suspend function hook has not been initialized 61 * idle states must not be enabled, so bail out 62 */ 63 if (!psci_ops.cpu_suspend) 64 return -EOPNOTSUPP; 65 66 /* Count idle states */ 67 while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states", 68 count))) { 69 count++; 70 of_node_put(state_node); 71 } 72 73 if (!count) 74 return -ENODEV; 75 76 psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL); 77 if (!psci_states) 78 return -ENOMEM; 79 80 for (i = 0; i < count; i++) { 81 u32 state; 82 83 state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i); 84 85 ret = of_property_read_u32(state_node, 86 "arm,psci-suspend-param", 87 &state); 88 if (ret) { 89 pr_warn(" * %s missing arm,psci-suspend-param property\n", 90 state_node->full_name); 91 of_node_put(state_node); 92 goto free_mem; 93 } 94 95 of_node_put(state_node); 96 pr_debug("psci-power-state %#x index %d\n", state, i); 97 if (!psci_power_state_is_valid(state)) { 98 pr_warn("Invalid PSCI power state %#x\n", state); 99 ret = -EINVAL; 100 goto free_mem; 101 } 102 psci_states[i] = state; 103 } 104 /* Idle states parsed correctly, initialize per-cpu pointer */ 105 per_cpu(psci_power_state, cpu) = psci_states; 106 return 0; 107 108 free_mem: 109 kfree(psci_states); 110 return ret; 111 } 112 113 static int __init cpu_psci_cpu_init(unsigned int cpu) 114 { 115 return 0; 116 } 117 118 static int __init cpu_psci_cpu_prepare(unsigned int cpu) 119 { 120 if (!psci_ops.cpu_on) { 121 pr_err("no cpu_on method, not booting CPU%d\n", cpu); 122 return -ENODEV; 123 } 124 125 return 0; 126 } 127 128 static int cpu_psci_cpu_boot(unsigned int cpu) 129 { 130 int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry)); 131 if (err) 132 pr_err("failed to boot CPU%d (%d)\n", cpu, err); 133 134 return err; 135 } 136 137 #ifdef CONFIG_HOTPLUG_CPU 138 static int cpu_psci_cpu_disable(unsigned int cpu) 139 { 140 /* Fail early if we don't have CPU_OFF support */ 141 if (!psci_ops.cpu_off) 142 return -EOPNOTSUPP; 143 144 /* Trusted OS will deny CPU_OFF */ 145 if (psci_tos_resident_on(cpu)) 146 return -EPERM; 147 148 return 0; 149 } 150 151 static void cpu_psci_cpu_die(unsigned int cpu) 152 { 153 int ret; 154 /* 155 * There are no known implementations of PSCI actually using the 156 * power state field, pass a sensible default for now. 157 */ 158 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN << 159 PSCI_0_2_POWER_STATE_TYPE_SHIFT; 160 161 ret = psci_ops.cpu_off(state); 162 163 pr_crit("unable to power off CPU%u (%d)\n", cpu, ret); 164 } 165 166 static int cpu_psci_cpu_kill(unsigned int cpu) 167 { 168 int err, i; 169 170 if (!psci_ops.affinity_info) 171 return 0; 172 /* 173 * cpu_kill could race with cpu_die and we can 174 * potentially end up declaring this cpu undead 175 * while it is dying. So, try again a few times. 176 */ 177 178 for (i = 0; i < 10; i++) { 179 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); 180 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { 181 pr_info("CPU%d killed.\n", cpu); 182 return 0; 183 } 184 185 msleep(10); 186 pr_info("Retrying again to check for CPU kill\n"); 187 } 188 189 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n", 190 cpu, err); 191 return -ETIMEDOUT; 192 } 193 #endif 194 195 static int psci_suspend_finisher(unsigned long index) 196 { 197 u32 *state = __this_cpu_read(psci_power_state); 198 199 return psci_ops.cpu_suspend(state[index - 1], 200 virt_to_phys(cpu_resume)); 201 } 202 203 static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index) 204 { 205 int ret; 206 u32 *state = __this_cpu_read(psci_power_state); 207 /* 208 * idle state index 0 corresponds to wfi, should never be called 209 * from the cpu_suspend operations 210 */ 211 if (WARN_ON_ONCE(!index)) 212 return -EINVAL; 213 214 if (!psci_power_state_loses_context(state[index - 1])) 215 ret = psci_ops.cpu_suspend(state[index - 1], 0); 216 else 217 ret = cpu_suspend(index, psci_suspend_finisher); 218 219 return ret; 220 } 221 222 const struct cpu_operations cpu_psci_ops = { 223 .name = "psci", 224 #ifdef CONFIG_CPU_IDLE 225 .cpu_init_idle = cpu_psci_cpu_init_idle, 226 .cpu_suspend = cpu_psci_cpu_suspend, 227 #endif 228 .cpu_init = cpu_psci_cpu_init, 229 .cpu_prepare = cpu_psci_cpu_prepare, 230 .cpu_boot = cpu_psci_cpu_boot, 231 #ifdef CONFIG_HOTPLUG_CPU 232 .cpu_disable = cpu_psci_cpu_disable, 233 .cpu_die = cpu_psci_cpu_die, 234 .cpu_kill = cpu_psci_cpu_kill, 235 #endif 236 }; 237 238