[linux-2.6-block.git] / drivers / clocksource / dummy_timer.c

/*
 *  linux/drivers/clocksource/dummy_timer.c
 *
 *  Copyright (C) 2013 ARM Ltd.
 *  All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/clockchips.h>
#include <linux/cpu.h>
#include <linux/init.h>
#include <linux/percpu.h>
#include <linux/cpumask.h>

static DEFINE_PER_CPU(struct clock_event_device, dummy_timer_evt);

static void dummy_timer_set_mode(enum clock_event_mode mode,
			   struct clock_event_device *evt)
{
	/*
	 * Core clockevents code will call this when exchanging timer devices.
	 * We don't need to do anything here.
	 */
}

static void dummy_timer_setup(void)
{
	int cpu = smp_processor_id();
	struct clock_event_device *evt = raw_cpu_ptr(&dummy_timer_evt);

	evt->name	= "dummy_timer";
	evt->features	= CLOCK_EVT_FEAT_PERIODIC |
			  CLOCK_EVT_FEAT_ONESHOT |
			  CLOCK_EVT_FEAT_DUMMY;
	evt->rating	= 100;
	evt->set_mode	= dummy_timer_set_mode;
	evt->cpumask	= cpumask_of(cpu);

	clockevents_register_device(evt);
}

static int dummy_timer_cpu_notify(struct notifier_block *self,
				      unsigned long action, void *hcpu)
{
	if ((action & ~CPU_TASKS_FROZEN) == CPU_STARTING)
		dummy_timer_setup();

	return NOTIFY_OK;
}

static struct notifier_block dummy_timer_cpu_nb = {
	.notifier_call = dummy_timer_cpu_notify,
};

static int __init dummy_timer_register(void)
{
	int err = 0;

	cpu_notifier_register_begin();
	err = __register_cpu_notifier(&dummy_timer_cpu_nb);
	if (err)
		goto out;

	/* We won't get a call on the boot CPU, so register immediately */
	if (num_possible_cpus() > 1)
		dummy_timer_setup();

out:
	cpu_notifier_register_done();
	return err;
}
early_initcall(dummy_timer_register);
Commit	Line	Data
06470651 MR	1	/*
	2	* linux/drivers/clocksource/dummy_timer.c
	3	*
	4	* Copyright (C) 2013 ARM Ltd.
	5	* All Rights Reserved
	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	#include <linux/clockchips.h>
	12	#include <linux/cpu.h>
	13	#include <linux/init.h>
	14	#include <linux/percpu.h>
	15	#include <linux/cpumask.h>
	16
	17	static DEFINE_PER_CPU(struct clock_event_device, dummy_timer_evt);
	18
	19	static void dummy_timer_set_mode(enum clock_event_mode mode,
	20	struct clock_event_device *evt)
	21	{
	22	/*
	23	* Core clockevents code will call this when exchanging timer devices.
	24	* We don't need to do anything here.
	25	*/
	26	}
	27
8c37bb3a	28	static void dummy_timer_setup(void)
06470651 MR	29	{
06470651 MR	30	int cpu = smp_processor_id();
22127e93	31	struct clock_event_device *evt = raw_cpu_ptr(&dummy_timer_evt);
06470651 MR	32
	33	evt->name = "dummy_timer";
	34	evt->features = CLOCK_EVT_FEAT_PERIODIC \|
	35	CLOCK_EVT_FEAT_ONESHOT \|
	36	CLOCK_EVT_FEAT_DUMMY;
	37	evt->rating = 100;
	38	evt->set_mode = dummy_timer_set_mode;
	39	evt->cpumask = cpumask_of(cpu);
	40
	41	clockevents_register_device(evt);
	42	}
	43
8c37bb3a	44	static int dummy_timer_cpu_notify(struct notifier_block *self,
06470651 MR	45	unsigned long action, void *hcpu)
	46	{
	47	if ((action & ~CPU_TASKS_FROZEN) == CPU_STARTING)
	48	dummy_timer_setup();
	49
	50	return NOTIFY_OK;
	51	}
	52
8c37bb3a	53	static struct notifier_block dummy_timer_cpu_nb = {
06470651 MR	54	.notifier_call = dummy_timer_cpu_notify,
	55	};
	56
	57	static int __init dummy_timer_register(void)
	58	{
8daa127f SB	59	int err = 0;
	60
	61	cpu_notifier_register_begin();
	62	err = __register_cpu_notifier(&dummy_timer_cpu_nb);
06470651	63	if (err)
8daa127f	64	goto out;
06470651 MR	65
	66	/* We won't get a call on the boot CPU, so register immediately */
	67	if (num_possible_cpus() > 1)
	68	dummy_timer_setup();
	69
8daa127f SB	70	out:
	71	cpu_notifier_register_done();
	72	return err;
06470651 MR	73	}
06470651 MR	74	early_initcall(dummy_timer_register);