blob: ad357254172890ff4170c2a32634f57ad831b26e [file] [log] [blame]
Mark Rutland06470652013-06-03 13:33:53 -07001/*
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
17static DEFINE_PER_CPU(struct clock_event_device, dummy_timer_evt);
18
19static 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
Paul Gortmaker8c37bb32013-06-19 11:32:08 -040028static void dummy_timer_setup(void)
Mark Rutland06470652013-06-03 13:33:53 -070029{
30 int cpu = smp_processor_id();
31 struct clock_event_device *evt = __this_cpu_ptr(&dummy_timer_evt);
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
Paul Gortmaker8c37bb32013-06-19 11:32:08 -040044static int dummy_timer_cpu_notify(struct notifier_block *self,
Mark Rutland06470652013-06-03 13:33:53 -070045 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
Paul Gortmaker8c37bb32013-06-19 11:32:08 -040053static struct notifier_block dummy_timer_cpu_nb = {
Mark Rutland06470652013-06-03 13:33:53 -070054 .notifier_call = dummy_timer_cpu_notify,
55};
56
57static int __init dummy_timer_register(void)
58{
Srivatsa S. Bhat8daa1272014-03-11 02:10:23 +053059 int err = 0;
60
61 cpu_notifier_register_begin();
62 err = __register_cpu_notifier(&dummy_timer_cpu_nb);
Mark Rutland06470652013-06-03 13:33:53 -070063 if (err)
Srivatsa S. Bhat8daa1272014-03-11 02:10:23 +053064 goto out;
Mark Rutland06470652013-06-03 13:33:53 -070065
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
Srivatsa S. Bhat8daa1272014-03-11 02:10:23 +053070out:
71 cpu_notifier_register_done();
72 return err;
Mark Rutland06470652013-06-03 13:33:53 -070073}
74early_initcall(dummy_timer_register);