blob: ac62f9cf1e100518ce719d10beb7110385b149ba [file] [log] [blame]
Chris Zankel5a0015d2005-06-23 22:01:16 -07001/*
2 * arch/xtensa/kernel/time.c
3 *
4 * Timer and clock support.
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 *
10 * Copyright (C) 2005 Tensilica Inc.
11 *
12 * Chris Zankel <chris@zankel.net>
13 */
14
Chris Zankel5a0015d2005-06-23 22:01:16 -070015#include <linux/errno.h>
Alexey Dobriyand43c36d2009-10-07 17:09:06 +040016#include <linux/sched.h>
Chris Zankel5a0015d2005-06-23 22:01:16 -070017#include <linux/time.h>
Johannes Weinerfcc8f0f2009-03-04 21:39:12 +010018#include <linux/clocksource.h>
Chris Zankel5a0015d2005-06-23 22:01:16 -070019#include <linux/interrupt.h>
20#include <linux/module.h>
21#include <linux/init.h>
22#include <linux/irq.h>
23#include <linux/profile.h>
24#include <linux/delay.h>
25
26#include <asm/timex.h>
27#include <asm/platform.h>
28
Chris Zankel5a0015d2005-06-23 22:01:16 -070029#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
30unsigned long ccount_per_jiffy; /* per 1/HZ */
Chris Zankel2b8aea72007-08-05 10:26:30 -070031unsigned long nsec_per_ccount; /* nsec per ccount increment */
Chris Zankel5a0015d2005-06-23 22:01:16 -070032#endif
33
Johannes Weinerfcc8f0f2009-03-04 21:39:12 +010034static cycle_t ccount_read(void)
35{
36 return (cycle_t)get_ccount();
37}
38
39static struct clocksource ccount_clocksource = {
40 .name = "ccount",
41 .rating = 200,
42 .read = ccount_read,
43 .mask = CLOCKSOURCE_MASK(32),
Johannes Weinerfcc8f0f2009-03-04 21:39:12 +010044};
45
Chris Zankelfd43fe12006-12-10 02:18:47 -080046static irqreturn_t timer_interrupt(int irq, void *dev_id);
Chris Zankel5a0015d2005-06-23 22:01:16 -070047static struct irqaction timer_irqaction = {
48 .handler = timer_interrupt,
Thomas Gleixner85ac3ab2006-07-01 19:29:31 -070049 .flags = IRQF_DISABLED,
Chris Zankel5a0015d2005-06-23 22:01:16 -070050 .name = "timer",
51};
52
53void __init time_init(void)
54{
Chris Zankel288a60c2005-09-22 21:44:23 -070055#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
Chris Zankel5a0015d2005-06-23 22:01:16 -070056 printk("Calibrating CPU frequency ");
57 platform_calibrate_ccount();
58 printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ),
59 (int)(ccount_per_jiffy/(10000/HZ))%100);
60#endif
John Stultza1397232010-04-26 20:25:56 -070061 clocksource_register_hz(&ccount_clocksource, CCOUNT_PER_JIFFY * HZ);
Chris Zankel5a0015d2005-06-23 22:01:16 -070062
63 /* Initialize the linux timer interrupt. */
64
65 setup_irq(LINUX_TIMER_INT, &timer_irqaction);
66 set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY);
67}
68
Chris Zankel5a0015d2005-06-23 22:01:16 -070069/*
70 * The timer interrupt is called HZ times per second.
71 */
72
Chris Zankelfd43fe12006-12-10 02:18:47 -080073irqreturn_t timer_interrupt (int irq, void *dev_id)
Chris Zankel5a0015d2005-06-23 22:01:16 -070074{
75
76 unsigned long next;
77
78 next = get_linux_timer();
79
80again:
81 while ((signed long)(get_ccount() - next) > 0) {
82
Chris Zankelfd43fe12006-12-10 02:18:47 -080083 profile_tick(CPU_PROFILING);
Chris Zankel5a0015d2005-06-23 22:01:16 -070084#ifndef CONFIG_SMP
Chris Zankelfd43fe12006-12-10 02:18:47 -080085 update_process_times(user_mode(get_irq_regs()));
Chris Zankel5a0015d2005-06-23 22:01:16 -070086#endif
87
Torben Hohnd12b0e22011-01-27 16:00:27 +010088 xtime_update(1); /* Linux handler in kernel/time/timekeeping */
Chris Zankel2b8aea72007-08-05 10:26:30 -070089
90 /* Note that writing CCOMPARE clears the interrupt. */
91
Chris Zankel5a0015d2005-06-23 22:01:16 -070092 next += CCOUNT_PER_JIFFY;
Chris Zankel2b8aea72007-08-05 10:26:30 -070093 set_linux_timer(next);
Chris Zankel5a0015d2005-06-23 22:01:16 -070094 }
95
Chris Zankel2b8aea72007-08-05 10:26:30 -070096 /* Allow platform to do something useful (Wdog). */
Chris Zankel5a0015d2005-06-23 22:01:16 -070097
Chris Zankel2b8aea72007-08-05 10:26:30 -070098 platform_heartbeat();
Chris Zankel5a0015d2005-06-23 22:01:16 -070099
100 /* Make sure we didn't miss any tick... */
101
102 if ((signed long)(get_ccount() - next) > 0)
103 goto again;
104
Chris Zankel5a0015d2005-06-23 22:01:16 -0700105 return IRQ_HANDLED;
106}
107
108#ifndef CONFIG_GENERIC_CALIBRATE_DELAY
Adrian Bunk6c81c322008-02-06 01:37:51 -0800109void __cpuinit calibrate_delay(void)
Chris Zankel5a0015d2005-06-23 22:01:16 -0700110{
111 loops_per_jiffy = CCOUNT_PER_JIFFY;
112 printk("Calibrating delay loop (skipped)... "
113 "%lu.%02lu BogoMIPS preset\n",
114 loops_per_jiffy/(1000000/HZ),
115 (loops_per_jiffy/(10000/HZ)) % 100);
116}
117#endif