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![Daniel Lezcano](/assets/img/avatar_default.png)
Some hardware have clusters with different idle states. The current code does not support this and fails as it expects all the idle states to be identical. Because of this, the Mediatek mtk8173 had to create the same idle state for a big.Little system and now the Hisilicon 960 is facing the same situation. Solve this by simply assuming the multiple driver will be needed for all the platforms using the ARM generic cpuidle driver which makes sense because of the different topologies we can support with a single kernel for ARM32 or ARM64. Every CPU has its own driver, so every single CPU can specify in the DT the idle states. This simple approach allows to support the future dynamIQ system, current SMP and HMP. Tested on: - 96boards: Hikey 620 - 96boards: Hikey 960 - 96boards: dragonboard410c - Mediatek 8173 Tested-by: Leo Yan <leo.yan@linaro.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
164 lines
4 KiB
C
164 lines
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
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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(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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drv = kmemdup(&arm_idle_driver, sizeof(*drv), GFP_KERNEL);
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if (!drv) {
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ret = -ENOMEM;
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goto out_fail;
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}
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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_fail;
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}
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ret = cpuidle_register_driver(drv);
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if (ret) {
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pr_err("Failed to register cpuidle driver\n");
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goto out_fail;
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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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continue;
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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_fail;
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}
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dev = kzalloc(sizeof(*dev), GFP_KERNEL);
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if (!dev) {
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pr_err("Failed to allocate cpuidle device\n");
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ret = -ENOMEM;
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goto out_fail;
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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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kfree(dev);
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goto out_fail;
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}
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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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cpuidle_unregister_device(dev);
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kfree(dev);
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drv = cpuidle_get_driver();
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cpuidle_unregister_driver(drv);
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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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