drivers/base/cpu.c

   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 }