LXR linux/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
  13struct sysdev_class cpu_sysdev_class = {
  14        set_kset_name("cpu"),
  15};
  16EXPORT_SYMBOL(cpu_sysdev_class);
  17
  18#ifdef CONFIG_HOTPLUG_CPU
  19static 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
  26static 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}
  49static SYSDEV_ATTR(online, 0600, show_online, store_online);
  50
  51static void __devinit register_cpu_control(struct cpu *cpu)
  52{
  53        sysdev_create_file(&cpu->sysdev, &attr_online);
  54}
  55void 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 */
  68static 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 */
  81int __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
 101int __init cpu_dev_init(void)
 102{
 103        return sysdev_class_register(&cpu_sysdev_class);
 104}
 105