/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}