1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * 4 * Copyright (C) 2012 ARM Limited 5 * 6 * Author: Will Deacon <will.deacon@arm.com> 7 */ 8 9 #include <linux/init.h> 10 #include <linux/smp.h> 11 #include <linux/of.h> 12 #include <linux/delay.h> 13 #include <linux/psci.h> 14 15 #include <uapi/linux/psci.h> 16 17 #include <asm/psci.h> 18 #include <asm/smp_plat.h> 19 20 /* 21 * psci_smp assumes that the following is true about PSCI: 22 * 23 * cpu_suspend Suspend the execution on a CPU 24 * @state we don't currently describe affinity levels, so just pass 0. 25 * @entry_point the first instruction to be executed on return 26 * returns 0 success, < 0 on failure 27 * 28 * cpu_off Power down a CPU 29 * @state we don't currently describe affinity levels, so just pass 0. 30 * no return on successful call 31 * 32 * cpu_on Power up a CPU 33 * @cpuid cpuid of target CPU, as from MPIDR 34 * @entry_point the first instruction to be executed on return 35 * returns 0 success, < 0 on failure 36 * 37 * migrate Migrate the context to a different CPU 38 * @cpuid cpuid of target CPU, as from MPIDR 39 * returns 0 success, < 0 on failure 40 * 41 */ 42 43 extern void secondary_startup(void); 44 45 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle) 46 { 47 if (psci_ops.cpu_on) 48 return psci_ops.cpu_on(cpu_logical_map(cpu), 49 virt_to_idmap(&secondary_startup)); 50 return -ENODEV; 51 } 52 53 #ifdef CONFIG_HOTPLUG_CPU 54 static int 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 psci_cpu_die(unsigned int cpu) 68 { 69 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN << 70 PSCI_0_2_POWER_STATE_TYPE_SHIFT; 71 72 if (psci_ops.cpu_off) 73 psci_ops.cpu_off(state); 74 75 /* We should never return */ 76 panic("psci: cpu %d failed to shutdown\n", cpu); 77 } 78 79 static int psci_cpu_kill(unsigned int cpu) 80 { 81 int err, i; 82 83 if (!psci_ops.affinity_info) 84 return 1; 85 /* 86 * cpu_kill could race with cpu_die and we can 87 * potentially end up declaring this cpu undead 88 * while it is dying. So, try again a few times. 89 */ 90 91 for (i = 0; i < 10; i++) { 92 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0); 93 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) { 94 pr_info("CPU%d killed.\n", cpu); 95 return 1; 96 } 97 98 msleep(10); 99 pr_info("Retrying again to check for CPU kill\n"); 100 } 101 102 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n", 103 cpu, err); 104 /* Make platform_cpu_kill() fail. */ 105 return 0; 106 } 107 108 #endif 109 110 bool __init psci_smp_available(void) 111 { 112 /* is cpu_on available at least? */ 113 return (psci_ops.cpu_on != NULL); 114 } 115 116 const struct smp_operations psci_smp_ops __initconst = { 117 .smp_boot_secondary = psci_boot_secondary, 118 #ifdef CONFIG_HOTPLUG_CPU 119 .cpu_disable = psci_cpu_disable, 120 .cpu_die = psci_cpu_die, 121 .cpu_kill = psci_cpu_kill, 122 #endif 123 }; 124