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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * ARM/ARM64 generic CPU idle driver.4 *5 * Copyright (C) 2014 ARM Ltd.6 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>7 */8 9#define pr_fmt(fmt) "CPUidle arm: " fmt10 11#include <linux/cpu_cooling.h>12#include <linux/cpuidle.h>13#include <linux/cpumask.h>14#include <linux/cpu_pm.h>15#include <linux/kernel.h>16#include <linux/module.h>17#include <linux/of.h>18#include <linux/slab.h>19 20#include <asm/cpuidle.h>21 22#include "dt_idle_states.h"23 24/*25 * arm_enter_idle_state - Programs CPU to enter the specified state26 *27 * dev: cpuidle device28 * drv: cpuidle driver29 * idx: state index30 *31 * Called from the CPUidle framework to program the device to the32 * specified target state selected by the governor.33 */34static __cpuidle int arm_enter_idle_state(struct cpuidle_device *dev,35 struct cpuidle_driver *drv, int idx)36{37 /*38 * Pass idle state index to arm_cpuidle_suspend which in turn39 * will call the CPU ops suspend protocol with idle index as a40 * parameter.41 */42 return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, idx);43}44 45static struct cpuidle_driver arm_idle_driver __initdata = {46 .name = "arm_idle",47 .owner = THIS_MODULE,48 /*49 * State at index 0 is standby wfi and considered standard50 * on all ARM platforms. If in some platforms simple wfi51 * can't be used as "state 0", DT bindings must be implemented52 * to work around this issue and allow installing a special53 * handler for idle state index 0.54 */55 .states[0] = {56 .enter = arm_enter_idle_state,57 .exit_latency = 1,58 .target_residency = 1,59 .power_usage = UINT_MAX,60 .name = "WFI",61 .desc = "ARM WFI",62 }63};64 65static const struct of_device_id arm_idle_state_match[] __initconst = {66 { .compatible = "arm,idle-state",67 .data = arm_enter_idle_state },68 { },69};70 71/*72 * arm_idle_init_cpu73 *74 * Registers the arm specific cpuidle driver with the cpuidle75 * framework. It relies on core code to parse the idle states76 * and initialize them using driver data structures accordingly.77 */78static int __init arm_idle_init_cpu(int cpu)79{80 int ret;81 struct cpuidle_driver *drv;82 83 drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL);84 if (!drv)85 return -ENOMEM;86 87 drv->cpumask = (struct cpumask *)cpumask_of(cpu);88 89 /*90 * Initialize idle states data, starting at index 1. This91 * driver is DT only, if no DT idle states are detected (ret92 * == 0) let the driver initialization fail accordingly since93 * there is no reason to initialize the idle driver if only94 * wfi is supported.95 */96 ret = dt_init_idle_driver(drv, arm_idle_state_match, 1);97 if (ret <= 0) {98 ret = ret ? : -ENODEV;99 goto out_kfree_drv;100 }101 102 /*103 * Call arch CPU operations in order to initialize104 * idle states suspend back-end specific data105 */106 ret = arm_cpuidle_init(cpu);107 108 /*109 * Allow the initialization to continue for other CPUs, if the110 * reported failure is a HW misconfiguration/breakage (-ENXIO).111 *112 * Some platforms do not support idle operations113 * (arm_cpuidle_init() returning -EOPNOTSUPP), we should114 * not flag this case as an error, it is a valid115 * configuration.116 */117 if (ret) {118 if (ret != -EOPNOTSUPP)119 pr_err("CPU %d failed to init idle CPU ops\n", cpu);120 ret = ret == -ENXIO ? 0 : ret;121 goto out_kfree_drv;122 }123 124 ret = cpuidle_register(drv, NULL);125 if (ret)126 goto out_kfree_drv;127 128 cpuidle_cooling_register(drv);129 130 return 0;131 132out_kfree_drv:133 kfree(drv);134 return ret;135}136 137/*138 * arm_idle_init - Initializes arm cpuidle driver139 *140 * Initializes arm cpuidle driver for all CPUs, if any CPU fails141 * to register cpuidle driver then rollback to cancel all CPUs142 * registeration.143 */144static int __init arm_idle_init(void)145{146 int cpu, ret;147 struct cpuidle_driver *drv;148 struct cpuidle_device *dev;149 150 for_each_possible_cpu(cpu) {151 ret = arm_idle_init_cpu(cpu);152 if (ret)153 goto out_fail;154 }155 156 return 0;157 158out_fail:159 while (--cpu >= 0) {160 dev = per_cpu(cpuidle_devices, cpu);161 drv = cpuidle_get_cpu_driver(dev);162 cpuidle_unregister(drv);163 kfree(drv);164 }165 166 return ret;167}168device_initcall(arm_idle_init);169