1 /* linux/arch/arm/mach-exynos4/cpuidle.c
2 *
3 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
4 * http://www.samsung.com
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/cpuidle.h>
14 #include <linux/io.h>
15 #include <linux/export.h>
16 #include <linux/time.h>
17
18 #include <asm/proc-fns.h>
19
20 static int exynos4_enter_idle(struct cpuidle_device *dev,
21 struct cpuidle_driver *drv,
22 int index);
23
24 static struct cpuidle_state exynos4_cpuidle_set[] = {
25 [0] = {
26 .enter = exynos4_enter_idle,
27 .exit_latency = 1,
28 .target_residency = 100000,
29 .flags = CPUIDLE_FLAG_TIME_VALID,
30 .name = "IDLE",
31 .desc = "ARM clock gating(WFI)",
32 },
33 };
34
35 static DEFINE_PER_CPU(struct cpuidle_device, exynos4_cpuidle_device);
36
37 static struct cpuidle_driver exynos4_idle_driver = {
38 .name = "exynos4_idle",
39 .owner = THIS_MODULE,
40 };
41
exynos4_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)42 static int exynos4_enter_idle(struct cpuidle_device *dev,
43 struct cpuidle_driver *drv,
44 int index)
45 {
46 struct timeval before, after;
47 int idle_time;
48
49 local_irq_disable();
50 do_gettimeofday(&before);
51
52 cpu_do_idle();
53
54 do_gettimeofday(&after);
55 local_irq_enable();
56 idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
57 (after.tv_usec - before.tv_usec);
58
59 dev->last_residency = idle_time;
60 return index;
61 }
62
exynos4_init_cpuidle(void)63 static int __init exynos4_init_cpuidle(void)
64 {
65 int i, max_cpuidle_state, cpu_id;
66 struct cpuidle_device *device;
67 struct cpuidle_driver *drv = &exynos4_idle_driver;
68
69 /* Setup cpuidle driver */
70 drv->state_count = (sizeof(exynos4_cpuidle_set) /
71 sizeof(struct cpuidle_state));
72 max_cpuidle_state = drv->state_count;
73 for (i = 0; i < max_cpuidle_state; i++) {
74 memcpy(&drv->states[i], &exynos4_cpuidle_set[i],
75 sizeof(struct cpuidle_state));
76 }
77 cpuidle_register_driver(&exynos4_idle_driver);
78
79 for_each_cpu(cpu_id, cpu_online_mask) {
80 device = &per_cpu(exynos4_cpuidle_device, cpu_id);
81 device->cpu = cpu_id;
82
83 device->state_count = drv->state_count;
84
85 if (cpuidle_register_device(device)) {
86 printk(KERN_ERR "CPUidle register device failed\n,");
87 return -EIO;
88 }
89 }
90 return 0;
91 }
92 device_initcall(exynos4_init_cpuidle);
93