projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 3299b63d LP |
1 | /* |
| 2 | * ARM64 generic CPU idle driver. | |
| 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 | ||
| 12 | #define pr_fmt(fmt) "CPUidle arm64: " fmt | |
| 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> | |
| 20 | ||
| 21 | #include <asm/cpuidle.h> | |
| 22 | #include <asm/suspend.h> | |
| 23 | ||
| 24 | #include "dt_idle_states.h" | |
| 25 | ||
| 26 | /* | |
| 27 | * arm64_enter_idle_state - Programs CPU to enter the specified state | |
| 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 | */ | |
| 36 | static int arm64_enter_idle_state(struct cpuidle_device *dev, | |
| 37 | struct cpuidle_driver *drv, int idx) | |
| 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 | */ | |
| 53 | ret = cpu_suspend(idx); | |
| 54 | ||
| 55 | cpu_pm_exit(); | |
| 56 | } | |
| 57 | ||
| 58 | return ret ? -1 : idx; | |
| 59 | } | |
| 60 | ||
| 61 | static struct cpuidle_driver arm64_idle_driver = { | |
| 62 | .name = "arm64_idle", | |
| 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] = { | |
| 72 | .enter = arm64_enter_idle_state, | |
| 73 | .exit_latency = 1, | |
| 74 | .target_residency = 1, | |
| 75 | .power_usage = UINT_MAX, | |
| 76 | .flags = CPUIDLE_FLAG_TIME_VALID, | |
| 77 | .name = "WFI", | |
| 78 | .desc = "ARM64 WFI", | |
| 79 | } | |
| 80 | }; | |
| 81 | ||
| 82 | static const struct of_device_id arm64_idle_state_match[] __initconst = { | |
| 83 | { .compatible = "arm,idle-state", | |
| 84 | .data = arm64_enter_idle_state }, | |
| 85 | { }, | |
| 86 | }; | |
| 87 | ||
| 88 | /* | |
| 89 | * arm64_idle_init | |
| 90 | * | |
| 91 | * Registers the arm64 specific cpuidle driver with the cpuidle | |
| 92 | * framework. It relies on core code to parse the idle states | |
| 93 | * and initialize them using driver data structures accordingly. | |
| 94 | */ | |
| 95 | static int __init arm64_idle_init(void) | |
| 96 | { | |
| 97 | int cpu, ret; | |
| 98 | struct cpuidle_driver *drv = &arm64_idle_driver; | |
| 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 | */ | |
| 106 | ret = dt_init_idle_driver(drv, arm64_idle_state_match, 1); | |
| 107 | if (ret <= 0) { | |
| 108 | if (ret) | |
| 109 | pr_err("failed to initialize idle states\n"); | |
| 110 | return ret ? : -ENODEV; | |
| 111 | } | |
| 112 | ||
| 113 | /* | |
| 114 | * Call arch CPU operations in order to initialize | |
| 115 | * idle states suspend back-end specific data | |
| 116 | */ | |
| 117 | for_each_possible_cpu(cpu) { | |
| 118 | ret = cpu_init_idle(cpu); | |
| 119 | if (ret) { | |
| 120 | pr_err("CPU %d failed to init idle CPU ops\n", cpu); | |
| 121 | return ret; | |
| 122 | } | |
| 123 | } | |
| 124 | ||
| 125 | ret = cpuidle_register(drv, NULL); | |
| 126 | if (ret) { | |
| 127 | pr_err("failed to register cpuidle driver\n"); | |
| 128 | return ret; | |
| 129 | } | |
| 130 | ||
| 131 | return 0; | |
| 132 | } | |
| 133 | device_initcall(arm64_idle_init); |