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 LP |
38 | { |
39 | int ret; | |
40 | ||
41 | if (!idx) { | |
42 | cpu_do_idle(); | |
43 | return idx; | |
44 | } | |
45 | ||
46 | ret = cpu_pm_enter(); | |
47 | if (!ret) { | |
48 | /* | |
49 | * Pass idle state index to cpu_suspend which in turn will | |
50 | * call the CPU ops suspend protocol with idle index as a | |
51 | * parameter. | |
52 | */ | |
191de17a | 53 | arm_cpuidle_suspend(idx); |
3299b63d LP |
54 | |
55 | cpu_pm_exit(); | |
56 | } | |
57 | ||
58 | return ret ? -1 : idx; | |
59 | } | |
60 | ||
69e6cb3d DL |
61 | static struct cpuidle_driver arm_idle_driver = { |
62 | .name = "arm_idle", | |
3299b63d LP |
63 | .owner = THIS_MODULE, |
64 | /* | |
65 | * State at index 0 is standby wfi and considered standard | |
66 | * on all ARM platforms. If in some platforms simple wfi | |
67 | * can't be used as "state 0", DT bindings must be implemented | |
68 | * to work around this issue and allow installing a special | |
69 | * handler for idle state index 0. | |
70 | */ | |
71 | .states[0] = { | |
69e6cb3d | 72 | .enter = arm_enter_idle_state, |
3299b63d LP |
73 | .exit_latency = 1, |
74 | .target_residency = 1, | |
75 | .power_usage = UINT_MAX, | |
3299b63d | 76 | .name = "WFI", |
69e6cb3d | 77 | .desc = "ARM WFI", |
3299b63d LP |
78 | } |
79 | }; | |
80 | ||
69e6cb3d | 81 | static const struct of_device_id arm_idle_state_match[] __initconst = { |
3299b63d | 82 | { .compatible = "arm,idle-state", |
69e6cb3d | 83 | .data = arm_enter_idle_state }, |
3299b63d LP |
84 | { }, |
85 | }; | |
86 | ||
87 | /* | |
69e6cb3d | 88 | * arm_idle_init |
3299b63d | 89 | * |
69e6cb3d | 90 | * Registers the arm specific cpuidle driver with the cpuidle |
3299b63d LP |
91 | * framework. It relies on core code to parse the idle states |
92 | * and initialize them using driver data structures accordingly. | |
93 | */ | |
69e6cb3d | 94 | static int __init arm_idle_init(void) |
3299b63d LP |
95 | { |
96 | int cpu, ret; | |
69e6cb3d | 97 | struct cpuidle_driver *drv = &arm_idle_driver; |
a0d46a3d | 98 | struct cpuidle_device *dev; |
3299b63d LP |
99 | |
100 | /* | |
101 | * Initialize idle states data, starting at index 1. | |
102 | * This driver is DT only, if no DT idle states are detected (ret == 0) | |
103 | * let the driver initialization fail accordingly since there is no | |
104 | * reason to initialize the idle driver if only wfi is supported. | |
105 | */ | |
69e6cb3d | 106 | ret = dt_init_idle_driver(drv, arm_idle_state_match, 1); |
18f95a36 | 107 | if (ret <= 0) |
3299b63d | 108 | return ret ? : -ENODEV; |
3299b63d | 109 | |
a0d46a3d DL |
110 | ret = cpuidle_register_driver(drv); |
111 | if (ret) { | |
112 | pr_err("Failed to register cpuidle driver\n"); | |
113 | return ret; | |
114 | } | |
115 | ||
3299b63d LP |
116 | /* |
117 | * Call arch CPU operations in order to initialize | |
118 | * idle states suspend back-end specific data | |
119 | */ | |
120 | for_each_possible_cpu(cpu) { | |
c9d62161 | 121 | ret = arm_cpuidle_init(cpu); |
a0d46a3d DL |
122 | |
123 | /* | |
124 | * Skip the cpuidle device initialization if the reported | |
125 | * failure is a HW misconfiguration/breakage (-ENXIO). | |
126 | */ | |
127 | if (ret == -ENXIO) | |
128 | continue; | |
129 | ||
3299b63d LP |
130 | if (ret) { |
131 | pr_err("CPU %d failed to init idle CPU ops\n", cpu); | |
a0d46a3d DL |
132 | goto out_fail; |
133 | } | |
134 | ||
135 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
136 | if (!dev) { | |
137 | pr_err("Failed to allocate cpuidle device\n"); | |
138 | goto out_fail; | |
139 | } | |
140 | dev->cpu = cpu; | |
141 | ||
142 | ret = cpuidle_register_device(dev); | |
143 | if (ret) { | |
144 | pr_err("Failed to register cpuidle device for CPU %d\n", | |
145 | cpu); | |
146 | kfree(dev); | |
147 | goto out_fail; | |
3299b63d LP |
148 | } |
149 | } | |
150 | ||
a0d46a3d DL |
151 | return 0; |
152 | out_fail: | |
153 | while (--cpu >= 0) { | |
154 | dev = per_cpu(cpuidle_devices, cpu); | |
155 | cpuidle_unregister_device(dev); | |
156 | kfree(dev); | |
157 | } | |
158 | ||
159 | cpuidle_unregister_driver(drv); | |
160 | ||
161 | return ret; | |
3299b63d | 162 | } |
69e6cb3d | 163 | device_initcall(arm_idle_init); |