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) 2012 ARM Limited 12 * 13 * Author: Will Deacon <will.deacon@arm.com> 14 */ 15 16 #include <linux/init.h> 17 #include <linux/smp.h> 18 #include <linux/of.h> 19 #include <linux/delay.h> 20 #include <linux/psci.h> 21 22 #include <uapi/linux/psci.h> 23 24 #include <asm/psci.h> 25 #include <asm/smp_plat.h> 26 27 /* 28 * psci_smp assumes that the following is true about PSCI: 29 * 30 * cpu_suspend Suspend the execution on a CPU 31 * @state we don't currently describe affinity levels, so just pass 0. 32 * @entry_point the first instruction to be executed on return 33 * returns 0 success, < 0 on failure 34 * 35 * cpu_off Power down a CPU 36 * @state we don't currently describe affinity levels, so just pass 0. 37 * no return on successful call 38 * 39 * cpu_on Power up a CPU 40 * @cpuid cpuid of target CPU, as from MPIDR 41 * @entry_point the first instruction to be executed on return 42 * returns 0 success, < 0 on failure 43 * 44 * migrate Migrate the context to a different CPU 45 * @cpuid cpuid of target CPU, as from MPIDR 46 * returns 0 success, < 0 on failure 47 * 48 */ 49 50 extern void secondary_startup(void); 51 52 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle) 53 { 54 if (psci_ops.cpu_on) 55 return psci_ops.cpu_on(cpu_logical_map(cpu), 56 virt_to_idmap(&secondary_startup)); 57 return -ENODEV; 58 } 59 60 #ifdef CONFIG_HOTPLUG_CPU 61 int psci_cpu_disable(unsigned int cpu) 62 { 63 /* Fail early if we don't have CPU_OFF support */ 64 if (!psci_ops.cpu_off) 65 return -EOPNOTSUPP; 66 67 /* Trusted OS will deny CPU_OFF */ 68 if (psci_tos_resident_on(cpu)) 69 return -EPERM; 70 71 return 0; 72 } 73 74 void __ref psci_cpu_die(unsigned int cpu) 75 { 76 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN << 77 PSCI_0_2_POWER_STATE_TYPE_SHIFT; 78 79 if (psci_ops.cpu_off) 80 psci_ops.cpu_off(state); 81 82 /* We should never return */ 83 panic("psci: cpu %d failed to shutdown\n", cpu); 84 } 85 86 int __ref psci_cpu_kill(unsigned int cpu) 87 { 88 int err, i; 89 90 if (!psci_ops.affinity_info) 91 return 1; 92 /* 93 * cpu_kill could race with cpu_die and we can 94 * potentially end up declaring this cpu undead 95 * while it is dying. So, try again a few times. 96 */ 97 98 for (i = 0; i < 10; i++) { 99 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); 100 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { 101 pr_info("CPU%d killed.\n", cpu); 102 return 1; 103 } 104 105 msleep(10); 106 pr_info("Retrying again to check for CPU kill\n"); 107 } 108 109 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n", 110 cpu, err); 111 /* Make platform_cpu_kill() fail. */ 112 return 0; 113 } 114 115 #endif 116 117 bool __init psci_smp_available(void) 118 { 119 /* is cpu_on available at least? */ 120 return (psci_ops.cpu_on != NULL); 121 } 122 123 struct smp_operations __initdata psci_smp_ops = { 124 .smp_boot_secondary = psci_boot_secondary, 125 #ifdef CONFIG_HOTPLUG_CPU 126 .cpu_disable = psci_cpu_disable, 127 .cpu_die = psci_cpu_die, 128 .cpu_kill = psci_cpu_kill, 129 #endif 130 }; 131