2 * arch/xtensa/kernel/time.c
4 * Timer and clock support.
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
10 * Copyright (C) 2005 Tensilica Inc.
12 * Chris Zankel <chris@zankel.net>
15 #include <linux/errno.h>
16 #include <linux/sched.h>
17 #include <linux/time.h>
18 #include <linux/clocksource.h>
19 #include <linux/clockchips.h>
20 #include <linux/interrupt.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/irq.h>
24 #include <linux/profile.h>
25 #include <linux/delay.h>
26 #include <linux/irqdomain.h>
27 #include <linux/sched_clock.h>
29 #include <asm/timex.h>
30 #include <asm/platform.h>
32 unsigned long ccount_freq; /* ccount Hz */
34 static cycle_t ccount_read(struct clocksource *cs)
36 return (cycle_t)get_ccount();
39 static u32 notrace ccount_sched_clock_read(void)
44 static struct clocksource ccount_clocksource = {
48 .mask = CLOCKSOURCE_MASK(32),
51 static int ccount_timer_set_next_event(unsigned long delta,
52 struct clock_event_device *dev);
53 static void ccount_timer_set_mode(enum clock_event_mode mode,
54 struct clock_event_device *evt);
55 static struct ccount_timer_t {
56 struct clock_event_device evt;
60 .name = "ccount_clockevent",
61 .features = CLOCK_EVT_FEAT_ONESHOT,
63 .set_next_event = ccount_timer_set_next_event,
64 .set_mode = ccount_timer_set_mode,
68 static int ccount_timer_set_next_event(unsigned long delta,
69 struct clock_event_device *dev)
71 unsigned long flags, next;
74 local_irq_save(flags);
75 next = get_ccount() + delta;
76 set_linux_timer(next);
77 if (next - get_ccount() > delta)
79 local_irq_restore(flags);
84 static void ccount_timer_set_mode(enum clock_event_mode mode,
85 struct clock_event_device *evt)
87 struct ccount_timer_t *timer =
88 container_of(evt, struct ccount_timer_t, evt);
91 * There is no way to disable the timer interrupt at the device level,
92 * only at the intenable register itself. Since enable_irq/disable_irq
93 * calls are nested, we need to make sure that these calls are
97 case CLOCK_EVT_MODE_SHUTDOWN:
98 case CLOCK_EVT_MODE_UNUSED:
99 if (timer->irq_enabled) {
100 disable_irq(evt->irq);
101 timer->irq_enabled = 0;
104 case CLOCK_EVT_MODE_RESUME:
105 case CLOCK_EVT_MODE_ONESHOT:
106 if (!timer->irq_enabled) {
107 enable_irq(evt->irq);
108 timer->irq_enabled = 1;
115 static irqreturn_t timer_interrupt(int irq, void *dev_id);
116 static struct irqaction timer_irqaction = {
117 .handler = timer_interrupt,
120 .dev_id = &ccount_timer,
123 void __init time_init(void)
125 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
126 printk("Calibrating CPU frequency ");
127 platform_calibrate_ccount();
128 printk("%d.%02d MHz\n", (int)ccount_freq/1000000,
129 (int)(ccount_freq/10000)%100);
131 ccount_freq = CONFIG_XTENSA_CPU_CLOCK*1000000UL;
133 clocksource_register_hz(&ccount_clocksource, ccount_freq);
135 ccount_timer.evt.cpumask = cpumask_of(0);
136 ccount_timer.evt.irq = irq_create_mapping(NULL, LINUX_TIMER_INT);
137 if (WARN(!ccount_timer.evt.irq, "error: can't map timer irq"))
139 clockevents_config_and_register(&ccount_timer.evt, ccount_freq, 0xf,
141 setup_irq(ccount_timer.evt.irq, &timer_irqaction);
142 ccount_timer.irq_enabled = 1;
144 setup_sched_clock(ccount_sched_clock_read, 32, ccount_freq);
148 * The timer interrupt is called HZ times per second.
151 irqreturn_t timer_interrupt (int irq, void *dev_id)
153 struct ccount_timer_t *timer = dev_id;
154 struct clock_event_device *evt = &timer->evt;
156 evt->event_handler(evt);
158 /* Allow platform to do something useful (Wdog). */
159 platform_heartbeat();
164 #ifndef CONFIG_GENERIC_CALIBRATE_DELAY
165 void calibrate_delay(void)
167 loops_per_jiffy = ccount_freq / HZ;
168 printk("Calibrating delay loop (skipped)... "
169 "%lu.%02lu BogoMIPS preset\n",
170 loops_per_jiffy/(1000000/HZ),
171 (loops_per_jiffy/(10000/HZ)) % 100);