cpu.c revision 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 
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