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Lorenzo Pieralisi3299b632014-02-28 13:03:44 +00001/*
Daniel Lezcano69e6cb32015-02-02 16:32:46 +01002 * ARM/ARM64 generic CPU idle driver.
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +00003 *
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
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010012#define pr_fmt(fmt) "CPUidle arm: " fmt
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000013
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>
Daniel Lezcanoa0d46a32015-03-05 16:44:42 +010020#include <linux/slab.h>
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000021
22#include <asm/cpuidle.h>
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000023
24#include "dt_idle_states.h"
25
26/*
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010027 * arm_enter_idle_state - Programs CPU to enter the specified state
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000028 *
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 */
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010036static int arm_enter_idle_state(struct cpuidle_device *dev,
37 struct cpuidle_driver *drv, int idx)
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000038{
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 */
Daniel Lezcano191de172015-02-02 16:32:45 +010053 arm_cpuidle_suspend(idx);
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000054
55 cpu_pm_exit();
56 }
57
58 return ret ? -1 : idx;
59}
60
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010061static struct cpuidle_driver arm_idle_driver = {
62 .name = "arm_idle",
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000063 .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] = {
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010072 .enter = arm_enter_idle_state,
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000073 .exit_latency = 1,
74 .target_residency = 1,
75 .power_usage = UINT_MAX,
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000076 .name = "WFI",
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010077 .desc = "ARM WFI",
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000078 }
79};
80
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010081static const struct of_device_id arm_idle_state_match[] __initconst = {
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000082 { .compatible = "arm,idle-state",
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010083 .data = arm_enter_idle_state },
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000084 { },
85};
86
87/*
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010088 * arm_idle_init
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000089 *
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010090 * Registers the arm specific cpuidle driver with the cpuidle
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000091 * framework. It relies on core code to parse the idle states
92 * and initialize them using driver data structures accordingly.
93 */
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010094static int __init arm_idle_init(void)
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000095{
96 int cpu, ret;
Daniel Lezcano69e6cb32015-02-02 16:32:46 +010097 struct cpuidle_driver *drv = &arm_idle_driver;
Daniel Lezcanoa0d46a32015-03-05 16:44:42 +010098 struct cpuidle_device *dev;
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +000099
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 */
Daniel Lezcano69e6cb32015-02-02 16:32:46 +0100106 ret = dt_init_idle_driver(drv, arm_idle_state_match, 1);
Lorenzo Pieralisi18f95a32014-10-15 18:29:54 +0100107 if (ret <= 0)
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +0000108 return ret ? : -ENODEV;
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +0000109
Daniel Lezcanoa0d46a32015-03-05 16:44:42 +0100110 ret = cpuidle_register_driver(drv);
111 if (ret) {
112 pr_err("Failed to register cpuidle driver\n");
113 return ret;
114 }
115
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +0000116 /*
117 * Call arch CPU operations in order to initialize
118 * idle states suspend back-end specific data
119 */
120 for_each_possible_cpu(cpu) {
Daniel Lezcanoc9d62162015-02-02 16:32:46 +0100121 ret = arm_cpuidle_init(cpu);
Daniel Lezcanoa0d46a32015-03-05 16:44:42 +0100122
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
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +0000130 if (ret) {
131 pr_err("CPU %d failed to init idle CPU ops\n", cpu);
Daniel Lezcanoa0d46a32015-03-05 16:44:42 +0100132 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;
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +0000148 }
149 }
150
Daniel Lezcanoa0d46a32015-03-05 16:44:42 +0100151 return 0;
152out_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;
Lorenzo Pieralisi3299b632014-02-28 13:03:44 +0000162}
Daniel Lezcano69e6cb32015-02-02 16:32:46 +0100163device_initcall(arm_idle_init);