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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
3299b63d | 2 | /* |
69e6cb3d | 3 | * ARM/ARM64 generic CPU idle driver. |
3299b63d LP |
4 | * |
5 | * Copyright (C) 2014 ARM Ltd. | |
6 | * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | |
3299b63d LP |
7 | */ |
8 | ||
69e6cb3d | 9 | #define pr_fmt(fmt) "CPUidle arm: " fmt |
3299b63d LP |
10 | |
11 | #include <linux/cpuidle.h> | |
12 | #include <linux/cpumask.h> | |
13 | #include <linux/cpu_pm.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/of.h> | |
a0d46a3d | 17 | #include <linux/slab.h> |
3299b63d LP |
18 | |
19 | #include <asm/cpuidle.h> | |
3299b63d LP |
20 | |
21 | #include "dt_idle_states.h" | |
22 | ||
23 | /* | |
69e6cb3d | 24 | * arm_enter_idle_state - Programs CPU to enter the specified state |
3299b63d LP |
25 | * |
26 | * dev: cpuidle device | |
27 | * drv: cpuidle driver | |
28 | * idx: state index | |
29 | * | |
30 | * Called from the CPUidle framework to program the device to the | |
31 | * specified target state selected by the governor. | |
32 | */ | |
69e6cb3d DL |
33 | static int arm_enter_idle_state(struct cpuidle_device *dev, |
34 | struct cpuidle_driver *drv, int idx) | |
3299b63d | 35 | { |
220276e0 SH |
36 | /* |
37 | * Pass idle state index to arm_cpuidle_suspend which in turn | |
38 | * will call the CPU ops suspend protocol with idle index as a | |
39 | * parameter. | |
40 | */ | |
41 | return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, idx); | |
3299b63d LP |
42 | } |
43 | ||
d50a7d8a | 44 | static struct cpuidle_driver arm_idle_driver __initdata = { |
69e6cb3d | 45 | .name = "arm_idle", |
3299b63d LP |
46 | .owner = THIS_MODULE, |
47 | /* | |
48 | * State at index 0 is standby wfi and considered standard | |
49 | * on all ARM platforms. If in some platforms simple wfi | |
50 | * can't be used as "state 0", DT bindings must be implemented | |
51 | * to work around this issue and allow installing a special | |
52 | * handler for idle state index 0. | |
53 | */ | |
54 | .states[0] = { | |
69e6cb3d | 55 | .enter = arm_enter_idle_state, |
3299b63d LP |
56 | .exit_latency = 1, |
57 | .target_residency = 1, | |
58 | .power_usage = UINT_MAX, | |
3299b63d | 59 | .name = "WFI", |
69e6cb3d | 60 | .desc = "ARM WFI", |
3299b63d LP |
61 | } |
62 | }; | |
63 | ||
69e6cb3d | 64 | static const struct of_device_id arm_idle_state_match[] __initconst = { |
3299b63d | 65 | { .compatible = "arm,idle-state", |
69e6cb3d | 66 | .data = arm_enter_idle_state }, |
3299b63d LP |
67 | { }, |
68 | }; | |
69 | ||
70 | /* | |
7943bfae | 71 | * arm_idle_init_cpu |
3299b63d | 72 | * |
69e6cb3d | 73 | * Registers the arm specific cpuidle driver with the cpuidle |
3299b63d LP |
74 | * framework. It relies on core code to parse the idle states |
75 | * and initialize them using driver data structures accordingly. | |
76 | */ | |
7943bfae | 77 | static int __init arm_idle_init_cpu(int cpu) |
3299b63d | 78 | { |
7943bfae | 79 | int ret; |
d50a7d8a | 80 | struct cpuidle_driver *drv; |
3299b63d | 81 | |
7943bfae LY |
82 | drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL); |
83 | if (!drv) | |
84 | return -ENOMEM; | |
d50a7d8a | 85 | |
7943bfae LY |
86 | drv->cpumask = (struct cpumask *)cpumask_of(cpu); |
87 | ||
88 | /* | |
89 | * Initialize idle states data, starting at index 1. This | |
90 | * driver is DT only, if no DT idle states are detected (ret | |
91 | * == 0) let the driver initialization fail accordingly since | |
92 | * there is no reason to initialize the idle driver if only | |
93 | * wfi is supported. | |
94 | */ | |
95 | ret = dt_init_idle_driver(drv, arm_idle_state_match, 1); | |
96 | if (ret <= 0) { | |
97 | ret = ret ? : -ENODEV; | |
98 | goto out_kfree_drv; | |
99 | } | |
100 | ||
7943bfae LY |
101 | /* |
102 | * Call arch CPU operations in order to initialize | |
103 | * idle states suspend back-end specific data | |
104 | */ | |
105 | ret = arm_cpuidle_init(cpu); | |
106 | ||
107 | /* | |
6460d7ba LP |
108 | * Allow the initialization to continue for other CPUs, if the |
109 | * reported failure is a HW misconfiguration/breakage (-ENXIO). | |
110 | * | |
111 | * Some platforms do not support idle operations | |
112 | * (arm_cpuidle_init() returning -EOPNOTSUPP), we should | |
113 | * not flag this case as an error, it is a valid | |
114 | * configuration. | |
7943bfae | 115 | */ |
7943bfae | 116 | if (ret) { |
6460d7ba LP |
117 | if (ret != -EOPNOTSUPP) |
118 | pr_err("CPU %d failed to init idle CPU ops\n", cpu); | |
763f191a UH |
119 | ret = ret == -ENXIO ? 0 : ret; |
120 | goto out_kfree_drv; | |
121 | } | |
122 | ||
3e452e63 UH |
123 | ret = cpuidle_register(drv, NULL); |
124 | if (ret) | |
763f191a | 125 | goto out_kfree_drv; |
3299b63d | 126 | |
a0d46a3d | 127 | return 0; |
0f87855d | 128 | |
0f87855d | 129 | out_kfree_drv: |
ed40fad9 | 130 | kfree(drv); |
7943bfae LY |
131 | return ret; |
132 | } | |
133 | ||
134 | /* | |
135 | * arm_idle_init - Initializes arm cpuidle driver | |
136 | * | |
137 | * Initializes arm cpuidle driver for all CPUs, if any CPU fails | |
138 | * to register cpuidle driver then rollback to cancel all CPUs | |
139 | * registeration. | |
140 | */ | |
141 | static int __init arm_idle_init(void) | |
142 | { | |
143 | int cpu, ret; | |
144 | struct cpuidle_driver *drv; | |
145 | struct cpuidle_device *dev; | |
146 | ||
147 | for_each_possible_cpu(cpu) { | |
148 | ret = arm_idle_init_cpu(cpu); | |
149 | if (ret) | |
150 | goto out_fail; | |
151 | } | |
152 | ||
153 | return 0; | |
154 | ||
a0d46a3d DL |
155 | out_fail: |
156 | while (--cpu >= 0) { | |
157 | dev = per_cpu(cpuidle_devices, cpu); | |
0f87855d | 158 | drv = cpuidle_get_cpu_driver(dev); |
3e452e63 | 159 | cpuidle_unregister(drv); |
d50a7d8a | 160 | kfree(drv); |
a0d46a3d DL |
161 | } |
162 | ||
a0d46a3d | 163 | return ret; |
3299b63d | 164 | } |
69e6cb3d | 165 | device_initcall(arm_idle_init); |