Commit | Line | Data |
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3299b63d | 1 | /* |
69e6cb3d | 2 | * ARM/ARM64 generic CPU idle driver. |
3299b63d LP |
3 | * |
4 | * Copyright (C) 2014 ARM Ltd. | |
5 | * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | ||
69e6cb3d | 12 | #define pr_fmt(fmt) "CPUidle arm: " fmt |
3299b63d LP |
13 | |
14 | #include <linux/cpuidle.h> | |
15 | #include <linux/cpumask.h> | |
16 | #include <linux/cpu_pm.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/of.h> | |
a0d46a3d | 20 | #include <linux/slab.h> |
3299b63d LP |
21 | |
22 | #include <asm/cpuidle.h> | |
3299b63d LP |
23 | |
24 | #include "dt_idle_states.h" | |
25 | ||
26 | /* | |
69e6cb3d | 27 | * arm_enter_idle_state - Programs CPU to enter the specified state |
3299b63d LP |
28 | * |
29 | * dev: cpuidle device | |
30 | * drv: cpuidle driver | |
31 | * idx: state index | |
32 | * | |
33 | * Called from the CPUidle framework to program the device to the | |
34 | * specified target state selected by the governor. | |
35 | */ | |
69e6cb3d DL |
36 | static int arm_enter_idle_state(struct cpuidle_device *dev, |
37 | struct cpuidle_driver *drv, int idx) | |
3299b63d | 38 | { |
220276e0 SH |
39 | /* |
40 | * Pass idle state index to arm_cpuidle_suspend which in turn | |
41 | * will call the CPU ops suspend protocol with idle index as a | |
42 | * parameter. | |
43 | */ | |
44 | return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, idx); | |
3299b63d LP |
45 | } |
46 | ||
69e6cb3d DL |
47 | static struct cpuidle_driver arm_idle_driver = { |
48 | .name = "arm_idle", | |
3299b63d LP |
49 | .owner = THIS_MODULE, |
50 | /* | |
51 | * State at index 0 is standby wfi and considered standard | |
52 | * on all ARM platforms. If in some platforms simple wfi | |
53 | * can't be used as "state 0", DT bindings must be implemented | |
54 | * to work around this issue and allow installing a special | |
55 | * handler for idle state index 0. | |
56 | */ | |
57 | .states[0] = { | |
69e6cb3d | 58 | .enter = arm_enter_idle_state, |
3299b63d LP |
59 | .exit_latency = 1, |
60 | .target_residency = 1, | |
61 | .power_usage = UINT_MAX, | |
3299b63d | 62 | .name = "WFI", |
69e6cb3d | 63 | .desc = "ARM WFI", |
3299b63d LP |
64 | } |
65 | }; | |
66 | ||
69e6cb3d | 67 | static const struct of_device_id arm_idle_state_match[] __initconst = { |
3299b63d | 68 | { .compatible = "arm,idle-state", |
69e6cb3d | 69 | .data = arm_enter_idle_state }, |
3299b63d LP |
70 | { }, |
71 | }; | |
72 | ||
73 | /* | |
69e6cb3d | 74 | * arm_idle_init |
3299b63d | 75 | * |
69e6cb3d | 76 | * Registers the arm specific cpuidle driver with the cpuidle |
3299b63d LP |
77 | * framework. It relies on core code to parse the idle states |
78 | * and initialize them using driver data structures accordingly. | |
79 | */ | |
69e6cb3d | 80 | static int __init arm_idle_init(void) |
3299b63d LP |
81 | { |
82 | int cpu, ret; | |
69e6cb3d | 83 | struct cpuidle_driver *drv = &arm_idle_driver; |
a0d46a3d | 84 | struct cpuidle_device *dev; |
3299b63d LP |
85 | |
86 | /* | |
87 | * Initialize idle states data, starting at index 1. | |
88 | * This driver is DT only, if no DT idle states are detected (ret == 0) | |
89 | * let the driver initialization fail accordingly since there is no | |
90 | * reason to initialize the idle driver if only wfi is supported. | |
91 | */ | |
69e6cb3d | 92 | ret = dt_init_idle_driver(drv, arm_idle_state_match, 1); |
18f95a36 | 93 | if (ret <= 0) |
3299b63d | 94 | return ret ? : -ENODEV; |
3299b63d | 95 | |
a0d46a3d DL |
96 | ret = cpuidle_register_driver(drv); |
97 | if (ret) { | |
98 | pr_err("Failed to register cpuidle driver\n"); | |
99 | return ret; | |
100 | } | |
101 | ||
3299b63d LP |
102 | /* |
103 | * Call arch CPU operations in order to initialize | |
104 | * idle states suspend back-end specific data | |
105 | */ | |
106 | for_each_possible_cpu(cpu) { | |
c9d62161 | 107 | ret = arm_cpuidle_init(cpu); |
a0d46a3d DL |
108 | |
109 | /* | |
110 | * Skip the cpuidle device initialization if the reported | |
111 | * failure is a HW misconfiguration/breakage (-ENXIO). | |
112 | */ | |
113 | if (ret == -ENXIO) | |
114 | continue; | |
115 | ||
3299b63d LP |
116 | if (ret) { |
117 | pr_err("CPU %d failed to init idle CPU ops\n", cpu); | |
a0d46a3d DL |
118 | goto out_fail; |
119 | } | |
120 | ||
121 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
122 | if (!dev) { | |
123 | pr_err("Failed to allocate cpuidle device\n"); | |
af48d7bc | 124 | ret = -ENOMEM; |
a0d46a3d DL |
125 | goto out_fail; |
126 | } | |
127 | dev->cpu = cpu; | |
128 | ||
129 | ret = cpuidle_register_device(dev); | |
130 | if (ret) { | |
131 | pr_err("Failed to register cpuidle device for CPU %d\n", | |
132 | cpu); | |
133 | kfree(dev); | |
134 | goto out_fail; | |
3299b63d LP |
135 | } |
136 | } | |
137 | ||
a0d46a3d DL |
138 | return 0; |
139 | out_fail: | |
140 | while (--cpu >= 0) { | |
141 | dev = per_cpu(cpuidle_devices, cpu); | |
142 | cpuidle_unregister_device(dev); | |
143 | kfree(dev); | |
144 | } | |
145 | ||
146 | cpuidle_unregister_driver(drv); | |
147 | ||
148 | return ret; | |
3299b63d | 149 | } |
69e6cb3d | 150 | device_initcall(arm_idle_init); |