1 /* 2 * drivers/base/cpu.c - basic CPU class support 3 */ 4 5 #include <linux/sysdev.h> 6 #include <linux/module.h> 7 #include <linux/init.h> 8 #include <linux/cpu.h> 9 #include <linux/topology.h> 10 #include <linux/device.h> 11 12 13 struct sysdev_class cpu_sysdev_class = { 14 set_kset_name("cpu"), 15 }; 16 EXPORT_SYMBOL(cpu_sysdev_class); 17 18 #ifdef CONFIG_HOTPLUG_CPU 19 static ssize_t show_online(struct sys_device *dev, char *buf) 20 { 21 struct cpu *cpu = container_of(dev, struct cpu, sysdev); 22 23 return sprintf(buf, "%u\n", !!cpu_online(cpu->sysdev.id)); 24 } 25 26 static ssize_t store_online(struct sys_device *dev, const char *buf, 27 size_t count) 28 { 29 struct cpu *cpu = container_of(dev, struct cpu, sysdev); 30 ssize_t ret; 31 32 switch (buf[0]) { 33 case '0': 34 ret = cpu_down(cpu->sysdev.id); 35 if (!ret) 36 kobject_hotplug(&dev->kobj, KOBJ_OFFLINE); 37 break; 38 case '1': 39 ret = cpu_up(cpu->sysdev.id); 40 break; 41 default: 42 ret = -EINVAL; 43 } 44 45 if (ret >= 0) 46 ret = count; 47 return ret; 48 } 49 static SYSDEV_ATTR(online, 0600, show_online, store_online); 50 51 static void __devinit register_cpu_control(struct cpu *cpu) 52 { 53 sysdev_create_file(&cpu->sysdev, &attr_online); 54 } 55 void unregister_cpu(struct cpu *cpu, struct node *root) 56 { 57 58 if (root) 59 sysfs_remove_link(&root->sysdev.kobj, 60 kobject_name(&cpu->sysdev.kobj)); 61 sysdev_remove_file(&cpu->sysdev, &attr_online); 62 63 sysdev_unregister(&cpu->sysdev); 64 65 return; 66 } 67 #else /* ... !CONFIG_HOTPLUG_CPU */ 68 static inline void register_cpu_control(struct cpu *cpu) 69 { 70 } 71 #endif /* CONFIG_HOTPLUG_CPU */ 72 73 /* 74 * register_cpu - Setup a driverfs device for a CPU. 75 * @cpu - Callers can set the cpu->no_control field to 1, to indicate not to 76 * generate a control file in sysfs for this CPU. 77 * @num - CPU number to use when creating the device. 78 * 79 * Initialize and register the CPU device. 80 */ 81 int __devinit register_cpu(struct cpu *cpu, int num, struct node *root) 82 { 83 int error; 84 85 cpu->node_id = cpu_to_node(num); 86 cpu->sysdev.id = num; 87 cpu->sysdev.cls = &cpu_sysdev_class; 88 89 error = sysdev_register(&cpu->sysdev); 90 if (!error && root) 91 error = sysfs_create_link(&root->sysdev.kobj, 92 &cpu->sysdev.kobj, 93 kobject_name(&cpu->sysdev.kobj)); 94 if (!error && !cpu->no_control) 95 register_cpu_control(cpu); 96 return error; 97 } 98 99 100 101 int __init cpu_dev_init(void) 102 { 103 return sysdev_class_register(&cpu_sysdev_class); 104 } 105