1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * based on arch/arm/mach-kirkwood/cpuidle.c
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * CPU idle support for AT91 SoC
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * This file is licensed under the terms of the GNU General Public
7*4882a593Smuzhiyun * License version 2. This program is licensed "as is" without any
8*4882a593Smuzhiyun * warranty of any kind, whether express or implied.
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * The cpu idle uses wait-for-interrupt and RAM self refresh in order
11*4882a593Smuzhiyun * to implement two idle states -
12*4882a593Smuzhiyun * #1 wait-for-interrupt
13*4882a593Smuzhiyun * #2 wait-for-interrupt and RAM self refresh
14*4882a593Smuzhiyun */
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #include <linux/kernel.h>
17*4882a593Smuzhiyun #include <linux/init.h>
18*4882a593Smuzhiyun #include <linux/platform_device.h>
19*4882a593Smuzhiyun #include <linux/cpuidle.h>
20*4882a593Smuzhiyun #include <linux/io.h>
21*4882a593Smuzhiyun #include <linux/export.h>
22*4882a593Smuzhiyun #include <asm/cpuidle.h>
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun #define AT91_MAX_STATES 2
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun static void (*at91_standby)(void);
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun /* Actual code that puts the SoC in different idle states */
at91_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)29*4882a593Smuzhiyun static int at91_enter_idle(struct cpuidle_device *dev,
30*4882a593Smuzhiyun struct cpuidle_driver *drv,
31*4882a593Smuzhiyun int index)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun at91_standby();
34*4882a593Smuzhiyun return index;
35*4882a593Smuzhiyun }
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun static struct cpuidle_driver at91_idle_driver = {
38*4882a593Smuzhiyun .name = "at91_idle",
39*4882a593Smuzhiyun .owner = THIS_MODULE,
40*4882a593Smuzhiyun .states[0] = ARM_CPUIDLE_WFI_STATE,
41*4882a593Smuzhiyun .states[1] = {
42*4882a593Smuzhiyun .enter = at91_enter_idle,
43*4882a593Smuzhiyun .exit_latency = 10,
44*4882a593Smuzhiyun .target_residency = 10000,
45*4882a593Smuzhiyun .name = "RAM_SR",
46*4882a593Smuzhiyun .desc = "WFI and DDR Self Refresh",
47*4882a593Smuzhiyun },
48*4882a593Smuzhiyun .state_count = AT91_MAX_STATES,
49*4882a593Smuzhiyun };
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun /* Initialize CPU idle by registering the idle states */
at91_cpuidle_probe(struct platform_device * dev)52*4882a593Smuzhiyun static int at91_cpuidle_probe(struct platform_device *dev)
53*4882a593Smuzhiyun {
54*4882a593Smuzhiyun at91_standby = (void *)(dev->dev.platform_data);
55*4882a593Smuzhiyun
56*4882a593Smuzhiyun return cpuidle_register(&at91_idle_driver, NULL);
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun static struct platform_driver at91_cpuidle_driver = {
60*4882a593Smuzhiyun .driver = {
61*4882a593Smuzhiyun .name = "cpuidle-at91",
62*4882a593Smuzhiyun },
63*4882a593Smuzhiyun .probe = at91_cpuidle_probe,
64*4882a593Smuzhiyun };
65*4882a593Smuzhiyun builtin_platform_driver(at91_cpuidle_driver);
66