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