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#define AT91_MAX_STATES	2
26
27static void (*at91_standby)(void);
28
29/* Actual code that puts the SoC in different idle states */
30static int at91_enter_idle(struct cpuidle_device *dev,
31			struct cpuidle_driver *drv,
32			       int index)
33{
34	at91_standby();
35	return index;
36}
37
38static struct cpuidle_driver at91_idle_driver = {
39	.name			= "at91_idle",
40	.owner			= THIS_MODULE,
41	.states[0]		= ARM_CPUIDLE_WFI_STATE,
42	.states[1]		= {
43		.enter			= at91_enter_idle,
44		.exit_latency		= 10,
45		.target_residency	= 10000,
46		.flags			= CPUIDLE_FLAG_TIME_VALID,
47		.name			= "RAM_SR",
48		.desc			= "WFI and DDR Self Refresh",
49	},
50	.state_count = AT91_MAX_STATES,
51};
52
53/* Initialize CPU idle by registering the idle states */
54static int at91_cpuidle_probe(struct platform_device *dev)
55{
56	at91_standby = (void *)(dev->dev.platform_data);
57
58	return cpuidle_register(&at91_idle_driver, NULL);
59}
60
61static struct platform_driver at91_cpuidle_driver = {
62	.driver = {
63		.name = "cpuidle-at91",
64		.owner = THIS_MODULE,
65	},
66	.probe = at91_cpuidle_probe,
67};
68
69module_platform_driver(at91_cpuidle_driver);
70