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![Sudeep Holla](/assets/img/avatar_default.png)
It's perfectly fine to have multiple cpuidle driver compiled in the build configuration. However, it's not good to throw error on driver registration failure if some other driver is already initialised and assigned. In such cases, __cpuidle_register_driver returns -EBUSY and we can check for such error before throwing the error. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
189 lines
4.4 KiB
C
189 lines
4.4 KiB
C
/*
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* ARM/ARM64 generic CPU idle driver.
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*
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* Copyright (C) 2014 ARM Ltd.
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* Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#define pr_fmt(fmt) "CPUidle arm: " fmt
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#include <linux/cpuidle.h>
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#include <linux/cpumask.h>
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#include <linux/cpu_pm.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/slab.h>
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#include <linux/topology.h>
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#include <asm/cpuidle.h>
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#include "dt_idle_states.h"
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/*
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* arm_enter_idle_state - Programs CPU to enter the specified state
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*
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* dev: cpuidle device
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* drv: cpuidle driver
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* idx: state index
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*
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* Called from the CPUidle framework to program the device to the
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* specified target state selected by the governor.
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*/
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static int arm_enter_idle_state(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int idx)
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{
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/*
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* Pass idle state index to arm_cpuidle_suspend which in turn
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* will call the CPU ops suspend protocol with idle index as a
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* parameter.
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*/
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return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, idx);
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}
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static struct cpuidle_driver arm_idle_driver __initdata = {
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.name = "arm_idle",
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.owner = THIS_MODULE,
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/*
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* State at index 0 is standby wfi and considered standard
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* on all ARM platforms. If in some platforms simple wfi
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* can't be used as "state 0", DT bindings must be implemented
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* to work around this issue and allow installing a special
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* handler for idle state index 0.
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*/
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.states[0] = {
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.enter = arm_enter_idle_state,
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.exit_latency = 1,
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.target_residency = 1,
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.power_usage = UINT_MAX,
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.name = "WFI",
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.desc = "ARM WFI",
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}
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};
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static const struct of_device_id arm_idle_state_match[] __initconst = {
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{ .compatible = "arm,idle-state",
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.data = arm_enter_idle_state },
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{ },
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};
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/*
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* arm_idle_init_cpu
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*
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* Registers the arm specific cpuidle driver with the cpuidle
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* framework. It relies on core code to parse the idle states
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* and initialize them using driver data structures accordingly.
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*/
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static int __init arm_idle_init_cpu(int cpu)
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{
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int ret;
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struct cpuidle_driver *drv;
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struct cpuidle_device *dev;
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drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL);
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if (!drv)
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return -ENOMEM;
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drv->cpumask = (struct cpumask *)cpumask_of(cpu);
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/*
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* Initialize idle states data, starting at index 1. This
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* driver is DT only, if no DT idle states are detected (ret
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* == 0) let the driver initialization fail accordingly since
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* there is no reason to initialize the idle driver if only
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* wfi is supported.
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*/
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ret = dt_init_idle_driver(drv, arm_idle_state_match, 1);
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if (ret <= 0) {
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ret = ret ? : -ENODEV;
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goto out_kfree_drv;
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}
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ret = cpuidle_register_driver(drv);
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if (ret) {
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if (ret != -EBUSY)
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pr_err("Failed to register cpuidle driver\n");
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goto out_kfree_drv;
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}
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/*
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* Call arch CPU operations in order to initialize
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* idle states suspend back-end specific data
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*/
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ret = arm_cpuidle_init(cpu);
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/*
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* Skip the cpuidle device initialization if the reported
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* failure is a HW misconfiguration/breakage (-ENXIO).
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*/
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if (ret == -ENXIO)
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return 0;
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if (ret) {
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pr_err("CPU %d failed to init idle CPU ops\n", cpu);
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goto out_unregister_drv;
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}
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dev = kzalloc(sizeof(*dev), GFP_KERNEL);
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if (!dev) {
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ret = -ENOMEM;
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goto out_unregister_drv;
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}
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dev->cpu = cpu;
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ret = cpuidle_register_device(dev);
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if (ret) {
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pr_err("Failed to register cpuidle device for CPU %d\n",
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cpu);
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goto out_kfree_dev;
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}
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return 0;
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out_kfree_dev:
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kfree(dev);
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out_unregister_drv:
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cpuidle_unregister_driver(drv);
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out_kfree_drv:
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kfree(drv);
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return ret;
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}
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/*
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* arm_idle_init - Initializes arm cpuidle driver
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*
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* Initializes arm cpuidle driver for all CPUs, if any CPU fails
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* to register cpuidle driver then rollback to cancel all CPUs
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* registeration.
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*/
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static int __init arm_idle_init(void)
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{
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int cpu, ret;
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struct cpuidle_driver *drv;
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struct cpuidle_device *dev;
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for_each_possible_cpu(cpu) {
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ret = arm_idle_init_cpu(cpu);
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if (ret)
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goto out_fail;
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}
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return 0;
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out_fail:
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while (--cpu >= 0) {
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dev = per_cpu(cpuidle_devices, cpu);
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drv = cpuidle_get_cpu_driver(dev);
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cpuidle_unregister_device(dev);
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cpuidle_unregister_driver(drv);
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kfree(dev);
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kfree(drv);
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}
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return ret;
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}
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device_initcall(arm_idle_init);
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