[linux-2.6-block.git] / drivers / cpuidle / cpuidle-haltpoll.c

// SPDX-License-Identifier: GPL-2.0
/*
 * cpuidle driver for haltpoll governor.
 *
 * Copyright 2019 Red Hat, Inc. and/or its affiliates.
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 * Authors: Marcelo Tosatti <mtosatti@redhat.com>
 */

#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/cpuidle.h>
#include <linux/module.h>
#include <linux/sched/idle.h>
#include <linux/kvm_para.h>
#include <linux/cpuidle_haltpoll.h>

static struct cpuidle_device __percpu *haltpoll_cpuidle_devices;
static enum cpuhp_state haltpoll_hp_state;

static int default_enter_idle(struct cpuidle_device *dev,
			      struct cpuidle_driver *drv, int index)
{
	if (current_clr_polling_and_test()) {
		local_irq_enable();
		return index;
	}
	default_idle();
	return index;
}

static struct cpuidle_driver haltpoll_driver = {
	.name = "haltpoll",
	.governor = "haltpoll",
	.states = {
		{ /* entry 0 is for polling */ },
		{
			.enter			= default_enter_idle,
			.exit_latency		= 1,
			.target_residency	= 1,
			.power_usage		= -1,
			.name			= "haltpoll idle",
			.desc			= "default architecture idle",
		},
	},
	.safe_state_index = 0,
	.state_count = 2,
};

static int haltpoll_cpu_online(unsigned int cpu)
{
	struct cpuidle_device *dev;

	dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
	if (!dev->registered) {
		dev->cpu = cpu;
		if (cpuidle_register_device(dev)) {
			pr_notice("cpuidle_register_device %d failed!\n", cpu);
			return -EIO;
		}
		arch_haltpoll_enable(cpu);
	}

	return 0;
}

static int haltpoll_cpu_offline(unsigned int cpu)
{
	struct cpuidle_device *dev;

	dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
	if (dev->registered) {
		arch_haltpoll_disable(cpu);
		cpuidle_unregister_device(dev);
	}

	return 0;
}

static void haltpoll_uninit(void)
{
	if (haltpoll_hp_state)
		cpuhp_remove_state(haltpoll_hp_state);
	cpuidle_unregister_driver(&haltpoll_driver);

	free_percpu(haltpoll_cpuidle_devices);
	haltpoll_cpuidle_devices = NULL;
}

static int __init haltpoll_init(void)
{
	int ret;
	struct cpuidle_driver *drv = &haltpoll_driver;

	cpuidle_poll_state_init(drv);

	if (!kvm_para_available() ||
		!kvm_para_has_hint(KVM_HINTS_REALTIME))
		return -ENODEV;

	ret = cpuidle_register_driver(drv);
	if (ret < 0)
		return ret;

	haltpoll_cpuidle_devices = alloc_percpu(struct cpuidle_device);
	if (haltpoll_cpuidle_devices == NULL) {
		cpuidle_unregister_driver(drv);
		return -ENOMEM;
	}

	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "cpuidle/haltpoll:online",
				haltpoll_cpu_online, haltpoll_cpu_offline);
	if (ret < 0) {
		haltpoll_uninit();
	} else {
		haltpoll_hp_state = ret;
		ret = 0;
	}

	return ret;
}

static void __exit haltpoll_exit(void)
{
	haltpoll_uninit();
}

module_init(haltpoll_init);
module_exit(haltpoll_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
Commit	Line	Data
fa86ee90 MT	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* cpuidle driver for haltpoll governor.
	4	*
	5	* Copyright 2019 Red Hat, Inc. and/or its affiliates.
	6	*
	7	* This work is licensed under the terms of the GNU GPL, version 2. See
	8	* the COPYING file in the top-level directory.
	9	*
	10	* Authors: Marcelo Tosatti <mtosatti@redhat.com>
	11	*/
	12
	13	#include <linux/init.h>
97d3eb9d	14	#include <linux/cpu.h>
fa86ee90 MT	15	#include <linux/cpuidle.h>
	16	#include <linux/module.h>
	17	#include <linux/sched/idle.h>
	18	#include <linux/kvm_para.h>
a1c4423b	19	#include <linux/cpuidle_haltpoll.h>
fa86ee90	20
97d3eb9d JM	21	static struct cpuidle_device __percpu *haltpoll_cpuidle_devices;
	22	static enum cpuhp_state haltpoll_hp_state;
	23
fa86ee90 MT	24	static int default_enter_idle(struct cpuidle_device *dev,
	25	struct cpuidle_driver *drv, int index)
	26	{
	27	if (current_clr_polling_and_test()) {
	28	local_irq_enable();
	29	return index;
	30	}
	31	default_idle();
	32	return index;
	33	}
	34
	35	static struct cpuidle_driver haltpoll_driver = {
	36	.name = "haltpoll",
73214408	37	.governor = "haltpoll",
fa86ee90 MT	38	.states = {
	39	{ /* entry 0 is for polling */ },
	40	{
	41	.enter = default_enter_idle,
	42	.exit_latency = 1,
	43	.target_residency = 1,
	44	.power_usage = -1,
	45	.name = "haltpoll idle",
	46	.desc = "default architecture idle",
	47	},
	48	},
	49	.safe_state_index = 0,
	50	.state_count = 2,
	51	};
	52
97d3eb9d JM	53	static int haltpoll_cpu_online(unsigned int cpu)
	54	{
	55	struct cpuidle_device *dev;
	56
	57	dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
	58	if (!dev->registered) {
	59	dev->cpu = cpu;
	60	if (cpuidle_register_device(dev)) {
	61	pr_notice("cpuidle_register_device %d failed!\n", cpu);
	62	return -EIO;
	63	}
	64	arch_haltpoll_enable(cpu);
	65	}
	66
	67	return 0;
	68	}
	69
	70	static int haltpoll_cpu_offline(unsigned int cpu)
	71	{
	72	struct cpuidle_device *dev;
	73
	74	dev = per_cpu_ptr(haltpoll_cpuidle_devices, cpu);
	75	if (dev->registered) {
	76	arch_haltpoll_disable(cpu);
	77	cpuidle_unregister_device(dev);
	78	}
	79
	80	return 0;
	81	}
	82
	83	static void haltpoll_uninit(void)
	84	{
	85	if (haltpoll_hp_state)
	86	cpuhp_remove_state(haltpoll_hp_state);
	87	cpuidle_unregister_driver(&haltpoll_driver);
	88
	89	free_percpu(haltpoll_cpuidle_devices);
	90	haltpoll_cpuidle_devices = NULL;
	91	}
	92
fa86ee90 MT	93	static int __init haltpoll_init(void)
fa86ee90 MT	94	{
a1c4423b	95	int ret;
fa86ee90 MT	96	struct cpuidle_driver *drv = &haltpoll_driver;
	97
	98	cpuidle_poll_state_init(drv);
	99
1328edca WL	100	if (!kvm_para_available() \|\|
1328edca WL	101	!kvm_para_has_hint(KVM_HINTS_REALTIME))
5cc59f59	102	return -ENODEV;
fa86ee90	103
97d3eb9d JM	104	ret = cpuidle_register_driver(drv);
	105	if (ret < 0)
	106	return ret;
	107
	108	haltpoll_cpuidle_devices = alloc_percpu(struct cpuidle_device);
	109	if (haltpoll_cpuidle_devices == NULL) {
	110	cpuidle_unregister_driver(drv);
	111	return -ENOMEM;
	112	}
	113
	114	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "cpuidle/haltpoll:online",
	115	haltpoll_cpu_online, haltpoll_cpu_offline);
	116	if (ret < 0) {
	117	haltpoll_uninit();
	118	} else {
	119	haltpoll_hp_state = ret;
	120	ret = 0;
	121	}
a1c4423b MT	122
a1c4423b MT	123	return ret;
fa86ee90 MT	124	}
	125
	126	static void __exit haltpoll_exit(void)
	127	{
97d3eb9d	128	haltpoll_uninit();
fa86ee90 MT	129	}
	130
	131	module_init(haltpoll_init);
	132	module_exit(haltpoll_exit);
	133	MODULE_LICENSE("GPL");
	134	MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");