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 phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry); 42 int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry); 43 if (err) 44 pr_err("failed to boot CPU%d (%d)\n", cpu, err); 45 46 return err; 47 } 48 49 #ifdef CONFIG_HOTPLUG_CPU 50 static bool cpu_psci_cpu_can_disable(unsigned int cpu) 51 { 52 return !psci_tos_resident_on(cpu); 53 } 54 55 static int cpu_psci_cpu_disable(unsigned int cpu) 56 { 57 /* Fail early if we don't have CPU_OFF support */ 58 if (!psci_ops.cpu_off) 59 return -EOPNOTSUPP; 60 61 /* Trusted OS will deny CPU_OFF */ 62 if (psci_tos_resident_on(cpu)) 63 return -EPERM; 64 65 return 0; 66 } 67 68 static void cpu_psci_cpu_die(unsigned int cpu) 69 { 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 psci_ops.cpu_off(state); 78 } 79 80 static int cpu_psci_cpu_kill(unsigned int cpu) 81 { 82 int err; 83 unsigned long start, end; 84 85 if (!psci_ops.affinity_info) 86 return 0; 87 /* 88 * cpu_kill could race with cpu_die and we can 89 * potentially end up declaring this cpu undead 90 * while it is dying. So, try again a few times. 91 */ 92 93 start = jiffies; 94 end = start + msecs_to_jiffies(100); 95 do { 96 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); 97 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { 98 pr_info("CPU%d killed (polled %d ms)\n", cpu, 99 jiffies_to_msecs(jiffies - start)); 100 return 0; 101 } 102 103 usleep_range(100, 1000); 104 } while (time_before(jiffies, end)); 105 106 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n", 107 cpu, err); 108 return -ETIMEDOUT; 109 } 110 #endif 111 112 const struct cpu_operations cpu_psci_ops = { 113 .name = "psci", 114 .cpu_init = cpu_psci_cpu_init, 115 .cpu_prepare = cpu_psci_cpu_prepare, 116 .cpu_boot = cpu_psci_cpu_boot, 117 #ifdef CONFIG_HOTPLUG_CPU 118 .cpu_can_disable = cpu_psci_cpu_can_disable, 119 .cpu_disable = cpu_psci_cpu_disable, 120 .cpu_die = cpu_psci_cpu_die, 121 .cpu_kill = cpu_psci_cpu_kill, 122 #endif 123 }; 124 125