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 #ifdef CONFIG_XIP_KERNEL 49 return psci_ops.cpu_on(cpu_logical_map(cpu), 50 ((phys_addr_t)(&secondary_startup) 51 - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) 52 + CONFIG_XIP_PHYS_ADDR)); 53 #else 54 return psci_ops.cpu_on(cpu_logical_map(cpu), 55 virt_to_idmap(&secondary_startup)); 56 #endif 57 return -ENODEV; 58 } 59 60 #ifdef CONFIG_HOTPLUG_CPU 61 static 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 static void 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 static int 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 const struct smp_operations psci_smp_ops __initconst = { 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