1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * arch/sh/kernel/cpu/shmobile/cpuidle.c
4  *
5  * Cpuidle support code for SuperH Mobile
6  *
7  *  Copyright (C) 2009 Magnus Damm
8  */
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/io.h>
12 #include <linux/suspend.h>
13 #include <linux/cpuidle.h>
14 #include <linux/export.h>
15 #include <asm/suspend.h>
16 #include <linux/uaccess.h>
17 
18 static unsigned long cpuidle_mode[] = {
19 	SUSP_SH_SLEEP, /* regular sleep mode */
20 	SUSP_SH_SLEEP | SUSP_SH_SF, /* sleep mode + self refresh */
21 	SUSP_SH_STANDBY | SUSP_SH_SF, /* software standby mode + self refresh */
22 };
23 
cpuidle_sleep_enter(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)24 static int cpuidle_sleep_enter(struct cpuidle_device *dev,
25 				struct cpuidle_driver *drv,
26 				int index)
27 {
28 	unsigned long allowed_mode = SUSP_SH_SLEEP;
29 	int requested_state = index;
30 	int allowed_state;
31 	int k;
32 
33 	/* convert allowed mode to allowed state */
34 	for (k = ARRAY_SIZE(cpuidle_mode) - 1; k > 0; k--)
35 		if (cpuidle_mode[k] == allowed_mode)
36 			break;
37 
38 	allowed_state = k;
39 
40 	/* take the following into account for sleep mode selection:
41 	 * - allowed_state: best mode allowed by hardware (clock deps)
42 	 * - requested_state: best mode allowed by software (latencies)
43 	 */
44 	k = min_t(int, allowed_state, requested_state);
45 
46 	sh_mobile_call_standby(cpuidle_mode[k]);
47 
48 	return k;
49 }
50 
51 static struct cpuidle_driver cpuidle_driver = {
52 	.name   = "sh_idle",
53 	.owner  = THIS_MODULE,
54 	.states = {
55 		{
56 			.exit_latency = 1,
57 			.target_residency = 1 * 2,
58 			.power_usage = 3,
59 			.enter = cpuidle_sleep_enter,
60 			.name = "C1",
61 			.desc = "SuperH Sleep Mode",
62 		},
63 		{
64 			.exit_latency = 100,
65 			.target_residency = 1 * 2,
66 			.power_usage = 1,
67 			.enter = cpuidle_sleep_enter,
68 			.name = "C2",
69 			.desc = "SuperH Sleep Mode [SF]",
70 			.flags = CPUIDLE_FLAG_UNUSABLE,
71 		},
72 		{
73 			.exit_latency = 2300,
74 			.target_residency = 1 * 2,
75 			.power_usage = 1,
76 			.enter = cpuidle_sleep_enter,
77 			.name = "C3",
78 			.desc = "SuperH Mobile Standby Mode [SF]",
79 			.flags = CPUIDLE_FLAG_UNUSABLE,
80 		},
81 	},
82 	.safe_state_index = 0,
83 	.state_count = 3,
84 };
85 
sh_mobile_setup_cpuidle(void)86 int __init sh_mobile_setup_cpuidle(void)
87 {
88 	if (sh_mobile_sleep_supported & SUSP_SH_SF)
89 		cpuidle_driver.states[1].flags = CPUIDLE_FLAG_NONE;
90 
91 	if (sh_mobile_sleep_supported & SUSP_SH_STANDBY)
92 		cpuidle_driver.states[2].flags = CPUIDLE_FLAG_NONE;
93 
94 	return cpuidle_register(&cpuidle_driver, NULL);
95 }
96