1/*
2 * arch/ubicom32/kernel/timer_broadcast.c
3 *   Implements a dummy clock event for each cpu.
4 *
5 * Copyright (C) 2008  Paul Mundt
6 * (C) Copyright 2009, Ubicom, Inc.
7 *
8 * This file is part of the Ubicom32 Linux Kernel Port.
9 *
10 * The Ubicom32 Linux Kernel Port is free software: you can redistribute
11 * it and/or modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation, either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * The Ubicom32 Linux Kernel Port is distributed in the hope that it
16 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
17 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
18 * the GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with the Ubicom32 Linux Kernel Port.  If not,
22 * see <http://www.gnu.org/licenses/>.
23 *
24 * Ubicom32 implementation derived from (with many thanks):
25 *   arch/m68knommu
26 *   arch/blackfin
27 *   arch/parisc
28 *   arch/arm
29 *   arch/sh
30 */
31#include <linux/init.h>
32#include <linux/kernel.h>
33#include <linux/delay.h>
34#include <linux/device.h>
35#include <linux/smp.h>
36#include <linux/jiffies.h>
37#include <linux/percpu.h>
38#include <linux/clockchips.h>
39#include <linux/irq.h>
40
41static DEFINE_PER_CPU(struct clock_event_device, local_clockevent);
42
43/*
44 *  The broadcast trick only works when the timer will be used in a periodic mode.
45 *  If the user has configured either NO_HZ or HIGH_RES_TIMERS they must have
46 *  a per cpu timer.
47 */
48#if defined(CONFIG_NO_HZ) || defined(CONFIG_HIGH_RES_TIMERS)
49#error "Tickless and High Resolution Timers require per-CPU local timers: CONFIG_LOCAL_TIMERS"
50#endif
51
52/*
53 * local_timer_interrupt()
54 *	Used on SMP for local timer interrupt sent via an IPI.
55 */
56void local_timer_interrupt(void)
57{
58	struct clock_event_device *dev = &__get_cpu_var(local_clockevent);
59
60	dev->event_handler(dev);
61}
62
63/*
64 * dummy_timer_set_next_event()
65 *	Cause the timer to go off "cycles" from now.
66 */
67static int dummy_timer_set_next_event(unsigned long cycles, struct clock_event_device *dev)
68{
69	return 0;
70}
71
72/*
73 * dummy_timer_set_mode()
74 *	Do Nothing.
75 */
76static void dummy_timer_set_mode(enum clock_event_mode mode,
77				 struct clock_event_device *clk)
78{
79}
80
81/*
82 * local_timer_setup()
83 *	Adds a clock event for the specified cpu.
84 */
85int __cpuinit local_timer_setup(unsigned int cpu)
86{
87	struct clock_event_device *dev = &per_cpu(local_clockevent, cpu);
88
89	dev->name		= "timer-dummy";
90	dev->features		= CLOCK_EVT_FEAT_DUMMY;
91	dev->rating		= 200;
92	dev->mult		= 1;
93	dev->set_mode		= dummy_timer_set_mode;
94	dev->set_next_event	= dummy_timer_set_next_event;
95	dev->broadcast		= smp_timer_broadcast;
96	dev->cpumask		= cpumask_of_cpu(cpu);
97	dev->irq		= -1;
98	printk(KERN_NOTICE "timer[%d]: %s - created\n", dev->irq, dev->name);
99
100	clockevents_register_device(dev);
101	return 0;
102}
103