1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2020 Western Digital Corporation or its affiliates. 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/mm.h> 8 #include <linux/sched.h> 9 #include <linux/err.h> 10 #include <linux/irq.h> 11 #include <linux/cpu.h> 12 #include <linux/sched/hotplug.h> 13 #include <asm/irq.h> 14 #include <asm/cpu_ops.h> 15 #include <asm/sbi.h> 16 17 bool cpu_has_hotplug(unsigned int cpu) 18 { 19 if (cpu_ops[cpu]->cpu_stop) 20 return true; 21 22 return false; 23 } 24 25 /* 26 * __cpu_disable runs on the processor to be shutdown. 27 */ 28 int __cpu_disable(void) 29 { 30 int ret = 0; 31 unsigned int cpu = smp_processor_id(); 32 33 if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_stop) 34 return -EOPNOTSUPP; 35 36 if (cpu_ops[cpu]->cpu_disable) 37 ret = cpu_ops[cpu]->cpu_disable(cpu); 38 39 if (ret) 40 return ret; 41 42 remove_cpu_topology(cpu); 43 set_cpu_online(cpu, false); 44 irq_migrate_all_off_this_cpu(); 45 46 return ret; 47 } 48 49 /* 50 * Called on the thread which is asking for a CPU to be shutdown. 51 */ 52 void __cpu_die(unsigned int cpu) 53 { 54 int ret = 0; 55 56 if (!cpu_wait_death(cpu, 5)) { 57 pr_err("CPU %u: didn't die\n", cpu); 58 return; 59 } 60 pr_notice("CPU%u: off\n", cpu); 61 62 /* Verify from the firmware if the cpu is really stopped*/ 63 if (cpu_ops[cpu]->cpu_is_stopped) 64 ret = cpu_ops[cpu]->cpu_is_stopped(cpu); 65 if (ret) 66 pr_warn("CPU%d may not have stopped: %d\n", cpu, ret); 67 } 68 69 /* 70 * Called from the idle thread for the CPU which has been shutdown. 71 */ 72 void arch_cpu_idle_dead(void) 73 { 74 idle_task_exit(); 75 76 (void)cpu_report_death(); 77 78 cpu_ops[smp_processor_id()]->cpu_stop(); 79 /* It should never reach here */ 80 BUG(); 81 } 82