1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * based on arch/arm/mach-kirkwood/cpuidle.c
4 *
5 * CPU idle support for AT91 SoC
6 *
7 * The cpu idle uses wait-for-interrupt and RAM self refresh in order
8 * to implement two idle states -
9 * #1 wait-for-interrupt
10 * #2 wait-for-interrupt and RAM self refresh
11 */
12
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/platform_device.h>
16 #include <linux/cpuidle.h>
17 #include <linux/io.h>
18 #include <linux/export.h>
19 #include <asm/cpuidle.h>
20
21 #define AT91_MAX_STATES 2
22
23 static void (*at91_standby)(void);
24
25 /* Actual code that puts the SoC in different idle states */
at91_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)26 static int at91_enter_idle(struct cpuidle_device *dev,
27 struct cpuidle_driver *drv,
28 int index)
29 {
30 at91_standby();
31 return index;
32 }
33
34 static struct cpuidle_driver at91_idle_driver = {
35 .name = "at91_idle",
36 .owner = THIS_MODULE,
37 .states[0] = ARM_CPUIDLE_WFI_STATE,
38 .states[1] = {
39 .enter = at91_enter_idle,
40 .exit_latency = 10,
41 .target_residency = 10000,
42 .name = "RAM_SR",
43 .desc = "WFI and DDR Self Refresh",
44 },
45 .state_count = AT91_MAX_STATES,
46 };
47
48 /* Initialize CPU idle by registering the idle states */
at91_cpuidle_probe(struct platform_device * dev)49 static int at91_cpuidle_probe(struct platform_device *dev)
50 {
51 at91_standby = (void *)(dev->dev.platform_data);
52
53 return cpuidle_register(&at91_idle_driver, NULL);
54 }
55
56 static struct platform_driver at91_cpuidle_driver = {
57 .driver = {
58 .name = "cpuidle-at91",
59 },
60 .probe = at91_cpuidle_probe,
61 };
62 builtin_platform_driver(at91_cpuidle_driver);
63