1 /*
2 * based on arch/arm/mach-kirkwood/cpuidle.c
3 *
4 * CPU idle support for AT91 SoC
5 *
6 * This file is licensed under the terms of the GNU General Public
7 * License version 2. This program is licensed "as is" without any
8 * warranty of any kind, whether express or implied.
9 *
10 * The cpu idle uses wait-for-interrupt and RAM self refresh in order
11 * to implement two idle states -
12 * #1 wait-for-interrupt
13 * #2 wait-for-interrupt and RAM self refresh
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/platform_device.h>
19 #include <linux/cpuidle.h>
20 #include <linux/io.h>
21 #include <linux/export.h>
22 #include <asm/proc-fns.h>
23 #include <asm/cpuidle.h>
24
25 #include "pm.h"
26
27 #define AT91_MAX_STATES 2
28
29 static DEFINE_PER_CPU(struct cpuidle_device, at91_cpuidle_device);
30
31 /* Actual code that puts the SoC in different idle states */
at91_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)32 static int at91_enter_idle(struct cpuidle_device *dev,
33 struct cpuidle_driver *drv,
34 int index)
35 {
36 at91_standby();
37
38 return index;
39 }
40
41 static struct cpuidle_driver at91_idle_driver = {
42 .name = "at91_idle",
43 .owner = THIS_MODULE,
44 .en_core_tk_irqen = 1,
45 .states[0] = ARM_CPUIDLE_WFI_STATE,
46 .states[1] = {
47 .enter = at91_enter_idle,
48 .exit_latency = 10,
49 .target_residency = 100000,
50 .flags = CPUIDLE_FLAG_TIME_VALID,
51 .name = "RAM_SR",
52 .desc = "WFI and DDR Self Refresh",
53 },
54 .state_count = AT91_MAX_STATES,
55 };
56
57 /* Initialize CPU idle by registering the idle states */
at91_init_cpuidle(void)58 static int at91_init_cpuidle(void)
59 {
60 struct cpuidle_device *device;
61
62 device = &per_cpu(at91_cpuidle_device, smp_processor_id());
63 device->state_count = AT91_MAX_STATES;
64
65 cpuidle_register_driver(&at91_idle_driver);
66
67 if (cpuidle_register_device(device)) {
68 printk(KERN_ERR "at91_init_cpuidle: Failed registering\n");
69 return -EIO;
70 }
71 return 0;
72 }
73
74 device_initcall(at91_init_cpuidle);
75