blob: 05ad29112ff491f393bfda90cbfcd12fc9d8dfd6 [file] [log] [blame]
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -07001/*
Hans-Christian Egtvedt77609892007-03-12 18:15:16 +01002 * Copyright (C) 2004-2007 Atmel Corporation
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -07003 *
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -07004 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -07008#include <linux/clk.h>
David Brownelle723ff62008-02-14 11:24:02 -08009#include <linux/clockchips.h>
Haavard Skinnemoen9dbef282008-05-28 13:07:40 +020010#include <linux/init.h>
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070011#include <linux/interrupt.h>
12#include <linux/irq.h>
Haavard Skinnemoen9dbef282008-05-28 13:07:40 +020013#include <linux/kernel.h>
14#include <linux/time.h>
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070015
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070016#include <asm/sysreg.h>
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070017
Haavard Skinnemoen3663b732008-08-05 13:57:38 +020018#include <mach/pm.h>
Hans-Christian Egtvedt77609892007-03-12 18:15:16 +010019
Hans-Christian Egtvedt77609892007-03-12 18:15:16 +010020
Magnus Damm8e196082009-04-21 12:24:00 -070021static cycle_t read_cycle_count(struct clocksource *cs)
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070022{
23 return (cycle_t)sysreg_read(COUNT);
24}
25
David Brownell62c6df62008-02-12 14:45:49 -080026/*
27 * The architectural cycle count registers are a fine clocksource unless
28 * the system idle loop use sleep states like "idle": the CPU cycles
29 * measured by COUNT (and COMPARE) don't happen during sleep states.
David Brownelle723ff62008-02-14 11:24:02 -080030 * Their duration also changes if cpufreq changes the CPU clock rate.
David Brownell62c6df62008-02-12 14:45:49 -080031 * So we rate the clocksource using COUNT as very low quality.
32 */
David Brownelle723ff62008-02-14 11:24:02 -080033static struct clocksource counter = {
34 .name = "avr32_counter",
David Brownell62c6df62008-02-12 14:45:49 -080035 .rating = 50,
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070036 .read = read_cycle_count,
37 .mask = CLOCKSOURCE_MASK(32),
Thomas Gleixner2693506c42007-02-16 01:27:38 -080038 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070039};
40
David Brownelle723ff62008-02-14 11:24:02 -080041static irqreturn_t timer_interrupt(int irq, void *dev_id)
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070042{
David Brownelle723ff62008-02-14 11:24:02 -080043 struct clock_event_device *evdev = dev_id;
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070044
Voss, Nikolaus56d3eef2008-07-18 14:44:48 +020045 if (unlikely(!(intc_get_pending(0) & 1)))
46 return IRQ_NONE;
47
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070048 /*
David Brownelle723ff62008-02-14 11:24:02 -080049 * Disable the interrupt until the clockevent subsystem
50 * reprograms it.
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070051 */
David Brownelle723ff62008-02-14 11:24:02 -080052 sysreg_write(COMPARE, 0);
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070053
David Brownelle723ff62008-02-14 11:24:02 -080054 evdev->event_handler(evdev);
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -070055 return IRQ_HANDLED;
56}
57
David Brownelle723ff62008-02-14 11:24:02 -080058static struct irqaction timer_irqaction = {
59 .handler = timer_interrupt,
Voss, Nikolaus56d3eef2008-07-18 14:44:48 +020060 /* Oprofile uses the same irq as the timer, so allow it to be shared */
61 .flags = IRQF_TIMER | IRQF_DISABLED | IRQF_SHARED,
David Brownelle723ff62008-02-14 11:24:02 -080062 .name = "avr32_comparator",
63};
64
65static int comparator_next_event(unsigned long delta,
66 struct clock_event_device *evdev)
67{
68 unsigned long flags;
69
70 raw_local_irq_save(flags);
71
72 /* The time to read COUNT then update COMPARE must be less
73 * than the min_delta_ns value for this clockevent source.
74 */
75 sysreg_write(COMPARE, (sysreg_read(COUNT) + delta) ? : 1);
76
77 raw_local_irq_restore(flags);
78
79 return 0;
80}
81
82static void comparator_mode(enum clock_event_mode mode,
83 struct clock_event_device *evdev)
84{
85 switch (mode) {
86 case CLOCK_EVT_MODE_ONESHOT:
87 pr_debug("%s: start\n", evdev->name);
88 /* FALLTHROUGH */
89 case CLOCK_EVT_MODE_RESUME:
90 cpu_disable_idle_sleep();
91 break;
92 case CLOCK_EVT_MODE_UNUSED:
93 case CLOCK_EVT_MODE_SHUTDOWN:
94 sysreg_write(COMPARE, 0);
95 pr_debug("%s: stop\n", evdev->name);
96 cpu_enable_idle_sleep();
97 break;
98 default:
99 BUG();
100 }
101}
102
103static struct clock_event_device comparator = {
104 .name = "avr32_comparator",
105 .features = CLOCK_EVT_FEAT_ONESHOT,
106 .shift = 16,
107 .rating = 50,
David Brownelle723ff62008-02-14 11:24:02 -0800108 .set_next_event = comparator_next_event,
109 .set_mode = comparator_mode,
110};
111
John Stultze2032a42010-03-03 19:57:21 -0800112void read_persistent_clock(struct timespec *ts)
113{
Peter Huewee9ddbc02010-04-27 15:23:01 +0200114 ts->tv_sec = mktime(2007, 1, 1, 0, 0, 0);
John Stultze2032a42010-03-03 19:57:21 -0800115 ts->tv_nsec = 0;
116}
117
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700118void __init time_init(void)
119{
David Brownelle723ff62008-02-14 11:24:02 -0800120 unsigned long counter_hz;
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700121 int ret;
122
David Brownelle723ff62008-02-14 11:24:02 -0800123 /* figure rate for counter */
124 counter_hz = clk_get_rate(boot_cpu_data.clk);
John Stultz1e2de472010-11-01 13:12:27 -0700125 ret = clocksource_register_hz(&counter, counter_hz);
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700126 if (ret)
Hans-Christian Egtvedt77609892007-03-12 18:15:16 +0100127 pr_debug("timer: could not register clocksource: %d\n", ret);
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700128
David Brownelle723ff62008-02-14 11:24:02 -0800129 /* setup COMPARE clockevent */
130 comparator.mult = div_sc(counter_hz, NSEC_PER_SEC, comparator.shift);
131 comparator.max_delta_ns = clockevent_delta2ns((u32)~0, &comparator);
132 comparator.min_delta_ns = clockevent_delta2ns(50, &comparator) + 1;
Rusty Russell320ab2b2008-12-13 21:20:26 +1030133 comparator.cpumask = cpumask_of(0);
David Brownelle723ff62008-02-14 11:24:02 -0800134
135 sysreg_write(COMPARE, 0);
136 timer_irqaction.dev_id = &comparator;
137
138 ret = setup_irq(0, &timer_irqaction);
139 if (ret)
140 pr_debug("timer: could not request IRQ 0: %d\n", ret);
141 else {
142 clockevents_register_device(&comparator);
143
144 pr_info("%s: irq 0, %lu.%03lu MHz\n", comparator.name,
145 ((counter_hz + 500) / 1000) / 1000,
146 ((counter_hz + 500) / 1000) % 1000);
Hans-Christian Egtvedt77609892007-03-12 18:15:16 +0100147 }
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -0700148}