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 /* 70 * There are no known implementations of PSCI actually using the 71 * power state field, pass a sensible default for now. 72 */ 73 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN << 74 PSCI_0_2_POWER_STATE_TYPE_SHIFT; 75 76 psci_ops.cpu_off(state); 77 } 78 79 static int cpu_psci_cpu_kill(unsigned int cpu) 80 { 81 int err; 82 unsigned long start, end; 83 84 if (!psci_ops.affinity_info) 85 return 0; 86 /* 87 * cpu_kill could race with cpu_die and we can 88 * potentially end up declaring this cpu undead 89 * while it is dying. So, try again a few times. 90 */ 91 92 start = jiffies; 93 end = start + msecs_to_jiffies(100); 94 do { 95 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); 96 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { 97 pr_info("CPU%d killed (polled %d ms)\n", cpu, 98 jiffies_to_msecs(jiffies - start)); 99 return 0; 100 } 101 102 usleep_range(100, 1000); 103 } while (time_before(jiffies, end)); 104 105 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n", 106 cpu, err); 107 return -ETIMEDOUT; 108 } 109 #endif 110 111 const struct cpu_operations cpu_psci_ops = { 112 .name = "psci", 113 .cpu_init = cpu_psci_cpu_init, 114 .cpu_prepare = cpu_psci_cpu_prepare, 115 .cpu_boot = cpu_psci_cpu_boot, 116 #ifdef CONFIG_HOTPLUG_CPU 117 .cpu_can_disable = cpu_psci_cpu_can_disable, 118 .cpu_disable = cpu_psci_cpu_disable, 119 .cpu_die = cpu_psci_cpu_die, 120 .cpu_kill = cpu_psci_cpu_kill, 121 #endif 122 }; 123 124