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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> |
d50a7d8a | 21 | #include <linux/topology.h> |
3299b63d LP |
22 | |
23 | #include <asm/cpuidle.h> | |
3299b63d LP |
24 | |
25 | #include "dt_idle_states.h" | |
26 | ||
27 | /* | |
69e6cb3d | 28 | * arm_enter_idle_state - Programs CPU to enter the specified state |
3299b63d LP |
29 | * |
30 | * dev: cpuidle device | |
31 | * drv: cpuidle driver | |
32 | * idx: state index | |
33 | * | |
34 | * Called from the CPUidle framework to program the device to the | |
35 | * specified target state selected by the governor. | |
36 | */ | |
69e6cb3d DL |
37 | static int arm_enter_idle_state(struct cpuidle_device *dev, |
38 | struct cpuidle_driver *drv, int idx) | |
3299b63d | 39 | { |
220276e0 SH |
40 | /* |
41 | * Pass idle state index to arm_cpuidle_suspend which in turn | |
42 | * will call the CPU ops suspend protocol with idle index as a | |
43 | * parameter. | |
44 | */ | |
45 | return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, idx); | |
3299b63d LP |
46 | } |
47 | ||
d50a7d8a | 48 | static struct cpuidle_driver arm_idle_driver __initdata = { |
69e6cb3d | 49 | .name = "arm_idle", |
3299b63d LP |
50 | .owner = THIS_MODULE, |
51 | /* | |
52 | * State at index 0 is standby wfi and considered standard | |
53 | * on all ARM platforms. If in some platforms simple wfi | |
54 | * can't be used as "state 0", DT bindings must be implemented | |
55 | * to work around this issue and allow installing a special | |
56 | * handler for idle state index 0. | |
57 | */ | |
58 | .states[0] = { | |
69e6cb3d | 59 | .enter = arm_enter_idle_state, |
3299b63d LP |
60 | .exit_latency = 1, |
61 | .target_residency = 1, | |
62 | .power_usage = UINT_MAX, | |
3299b63d | 63 | .name = "WFI", |
69e6cb3d | 64 | .desc = "ARM WFI", |
3299b63d LP |
65 | } |
66 | }; | |
67 | ||
69e6cb3d | 68 | static const struct of_device_id arm_idle_state_match[] __initconst = { |
3299b63d | 69 | { .compatible = "arm,idle-state", |
69e6cb3d | 70 | .data = arm_enter_idle_state }, |
3299b63d LP |
71 | { }, |
72 | }; | |
73 | ||
74 | /* | |
69e6cb3d | 75 | * arm_idle_init |
3299b63d | 76 | * |
69e6cb3d | 77 | * Registers the arm specific cpuidle driver with the cpuidle |
3299b63d LP |
78 | * framework. It relies on core code to parse the idle states |
79 | * and initialize them using driver data structures accordingly. | |
80 | */ | |
69e6cb3d | 81 | static int __init arm_idle_init(void) |
3299b63d LP |
82 | { |
83 | int cpu, ret; | |
d50a7d8a | 84 | struct cpuidle_driver *drv; |
a0d46a3d | 85 | struct cpuidle_device *dev; |
3299b63d | 86 | |
3299b63d | 87 | for_each_possible_cpu(cpu) { |
d50a7d8a DL |
88 | |
89 | drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL); | |
90 | if (!drv) { | |
91 | ret = -ENOMEM; | |
92 | goto out_fail; | |
93 | } | |
94 | ||
95 | drv->cpumask = (struct cpumask *)cpumask_of(cpu); | |
96 | ||
97 | /* | |
98 | * Initialize idle states data, starting at index 1. This | |
99 | * driver is DT only, if no DT idle states are detected (ret | |
100 | * == 0) let the driver initialization fail accordingly since | |
101 | * there is no reason to initialize the idle driver if only | |
102 | * wfi is supported. | |
103 | */ | |
104 | ret = dt_init_idle_driver(drv, arm_idle_state_match, 1); | |
105 | if (ret <= 0) { | |
106 | ret = ret ? : -ENODEV; | |
107 | goto out_fail; | |
108 | } | |
109 | ||
110 | ret = cpuidle_register_driver(drv); | |
111 | if (ret) { | |
112 | pr_err("Failed to register cpuidle driver\n"); | |
113 | goto out_fail; | |
114 | } | |
115 | ||
116 | /* | |
117 | * Call arch CPU operations in order to initialize | |
118 | * idle states suspend back-end specific data | |
119 | */ | |
c9d62161 | 120 | ret = arm_cpuidle_init(cpu); |
a0d46a3d DL |
121 | |
122 | /* | |
123 | * Skip the cpuidle device initialization if the reported | |
124 | * failure is a HW misconfiguration/breakage (-ENXIO). | |
125 | */ | |
126 | if (ret == -ENXIO) | |
127 | continue; | |
128 | ||
3299b63d LP |
129 | if (ret) { |
130 | pr_err("CPU %d failed to init idle CPU ops\n", cpu); | |
a0d46a3d DL |
131 | goto out_fail; |
132 | } | |
133 | ||
134 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
135 | if (!dev) { | |
136 | pr_err("Failed to allocate cpuidle device\n"); | |
af48d7bc | 137 | ret = -ENOMEM; |
a0d46a3d DL |
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); | |
d50a7d8a DL |
157 | drv = cpuidle_get_driver(); |
158 | cpuidle_unregister_driver(drv); | |
159 | kfree(drv); | |
a0d46a3d DL |
160 | } |
161 | ||
a0d46a3d | 162 | return ret; |
3299b63d | 163 | } |
69e6cb3d | 164 | device_initcall(arm_idle_init); |