1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * 4 * Copyright (C) 2013 ARM Limited 5 * 6 * Author: Will Deacon <will.deacon@arm.com> 7 */ 8 9 #define pr_fmt(fmt) "psci: " fmt 10 11 #include <linux/init.h> 12 #include <linux/of.h> 13 #include <linux/smp.h> 14 #include <linux/delay.h> 15 #include <linux/psci.h> 16 #include <linux/mm.h> 17 18 #include <uapi/linux/psci.h> 19 20 #include <asm/cpu_ops.h> 21 #include <asm/errno.h> 22 #include <asm/smp_plat.h> 23 24 static int __init cpu_psci_cpu_init(unsigned int cpu) 25 { 26 return 0; 27 } 28 29 static int __init cpu_psci_cpu_prepare(unsigned int cpu) 30 { 31 if (!psci_ops.cpu_on) { 32 pr_err("no cpu_on method, not booting CPU%d\n", cpu); 33 return -ENODEV; 34 } 35 36 return 0; 37 } 38 39 static int cpu_psci_cpu_boot(unsigned int cpu) 40 { 41 int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa_symbol(secondary_entry)); 42 if (err) 43 pr_err("failed to boot CPU%d (%d)\n", cpu, err); 44 45 return err; 46 } 47 48 #ifdef CONFIG_HOTPLUG_CPU 49 static bool cpu_psci_cpu_can_disable(unsigned int cpu) 50 { 51 return !psci_tos_resident_on(cpu); 52 } 53 54 static int cpu_psci_cpu_disable(unsigned int cpu) 55 { 56 /* Fail early if we don't have CPU_OFF support */ 57 if (!psci_ops.cpu_off) 58 return -EOPNOTSUPP; 59 60 /* Trusted OS will deny CPU_OFF */ 61 if (psci_tos_resident_on(cpu)) 62 return -EPERM; 63 64 return 0; 65 } 66 67 static void cpu_psci_cpu_die(unsigned int cpu) 68 { 69 int ret; 70 /* 71 * There are no known implementations of PSCI actually using the 72 * power state field, pass a sensible default for now. 73 */ 74 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN << 75 PSCI_0_2_POWER_STATE_TYPE_SHIFT; 76 77 ret = psci_ops.cpu_off(state); 78 79 pr_crit("unable to power off CPU%u (%d)\n", cpu, ret); 80 } 81 82 static int cpu_psci_cpu_kill(unsigned int cpu) 83 { 84 int err; 85 unsigned long start, end; 86 87 if (!psci_ops.affinity_info) 88 return 0; 89 /* 90 * cpu_kill could race with cpu_die and we can 91 * potentially end up declaring this cpu undead 92 * while it is dying. So, try again a few times. 93 */ 94 95 start = jiffies; 96 end = start + msecs_to_jiffies(100); 97 do { 98 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); 99 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { 100 pr_info("CPU%d killed (polled %d ms)\n", cpu, 101 jiffies_to_msecs(jiffies - start)); 102 return 0; 103 } 104 105 usleep_range(100, 1000); 106 } while (time_before(jiffies, end)); 107 108 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n", 109 cpu, err); 110 return -ETIMEDOUT; 111 } 112 #endif 113 114 const struct cpu_operations cpu_psci_ops = { 115 .name = "psci", 116 .cpu_init = cpu_psci_cpu_init, 117 .cpu_prepare = cpu_psci_cpu_prepare, 118 .cpu_boot = cpu_psci_cpu_boot, 119 #ifdef CONFIG_HOTPLUG_CPU 120 .cpu_can_disable = cpu_psci_cpu_can_disable, 121 .cpu_disable = cpu_psci_cpu_disable, 122 .cpu_die = cpu_psci_cpu_die, 123 .cpu_kill = cpu_psci_cpu_kill, 124 #endif 125 }; 126 127