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/mm.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 32 static int __init cpu_psci_cpu_init(unsigned int cpu) 33 { 34 return 0; 35 } 36 37 static int __init cpu_psci_cpu_prepare(unsigned int cpu) 38 { 39 if (!psci_ops.cpu_on) { 40 pr_err("no cpu_on method, not booting CPU%d\n", cpu); 41 return -ENODEV; 42 } 43 44 return 0; 45 } 46 47 static int cpu_psci_cpu_boot(unsigned int cpu) 48 { 49 int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa_symbol(secondary_entry)); 50 if (err) 51 pr_err("failed to boot CPU%d (%d)\n", cpu, err); 52 53 return err; 54 } 55 56 #ifdef CONFIG_HOTPLUG_CPU 57 static int cpu_psci_cpu_disable(unsigned int cpu) 58 { 59 /* Fail early if we don't have CPU_OFF support */ 60 if (!psci_ops.cpu_off) 61 return -EOPNOTSUPP; 62 63 /* Trusted OS will deny CPU_OFF */ 64 if (psci_tos_resident_on(cpu)) 65 return -EPERM; 66 67 return 0; 68 } 69 70 static void cpu_psci_cpu_die(unsigned int cpu) 71 { 72 int ret; 73 /* 74 * There are no known implementations of PSCI actually using the 75 * power state field, pass a sensible default for now. 76 */ 77 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN << 78 PSCI_0_2_POWER_STATE_TYPE_SHIFT; 79 80 ret = psci_ops.cpu_off(state); 81 82 pr_crit("unable to power off CPU%u (%d)\n", cpu, ret); 83 } 84 85 static int cpu_psci_cpu_kill(unsigned int cpu) 86 { 87 int err, i; 88 89 if (!psci_ops.affinity_info) 90 return 0; 91 /* 92 * cpu_kill could race with cpu_die and we can 93 * potentially end up declaring this cpu undead 94 * while it is dying. So, try again a few times. 95 */ 96 97 for (i = 0; i < 10; i++) { 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.\n", cpu); 101 return 0; 102 } 103 104 msleep(10); 105 pr_info("Retrying again to check for CPU kill\n"); 106 } 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 #ifdef CONFIG_CPU_IDLE 117 .cpu_init_idle = psci_cpu_init_idle, 118 .cpu_suspend = psci_cpu_suspend_enter, 119 #endif 120 .cpu_init = cpu_psci_cpu_init, 121 .cpu_prepare = cpu_psci_cpu_prepare, 122 .cpu_boot = cpu_psci_cpu_boot, 123 #ifdef CONFIG_HOTPLUG_CPU 124 .cpu_disable = cpu_psci_cpu_disable, 125 .cpu_die = cpu_psci_cpu_die, 126 .cpu_kill = cpu_psci_cpu_kill, 127 #endif 128 }; 129 130