1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
/*
* Copyright (C) 2004-2007 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/cpu.h>
#include <asm/sysreg.h>
#include <mach/pm.h>
static cycle_t read_cycle_count(struct clocksource *cs)
{
return (cycle_t)sysreg_read(COUNT);
}
/*
* The architectural cycle count registers are a fine clocksource unless
* the system idle loop use sleep states like "idle": the CPU cycles
* measured by COUNT (and COMPARE) don't happen during sleep states.
* Their duration also changes if cpufreq changes the CPU clock rate.
* So we rate the clocksource using COUNT as very low quality.
*/
static struct clocksource counter = {
.name = "avr32_counter",
.rating = 50,
.read = read_cycle_count,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evdev = dev_id;
if (unlikely(!(intc_get_pending(0) & 1)))
return IRQ_NONE;
/*
* Disable the interrupt until the clockevent subsystem
* reprograms it.
*/
sysreg_write(COMPARE, 0);
evdev->event_handler(evdev);
return IRQ_HANDLED;
}
static struct irqaction timer_irqaction = {
.handler = timer_interrupt,
/* Oprofile uses the same irq as the timer, so allow it to be shared */
.flags = IRQF_TIMER | IRQF_DISABLED | IRQF_SHARED,
.name = "avr32_comparator",
};
static int comparator_next_event(unsigned long delta,
struct clock_event_device *evdev)
{
unsigned long flags;
raw_local_irq_save(flags);
/* The time to read COUNT then update COMPARE must be less
* than the min_delta_ns value for this clockevent source.
*/
sysreg_write(COMPARE, (sysreg_read(COUNT) + delta) ? : 1);
raw_local_irq_restore(flags);
return 0;
}
static void comparator_mode(enum clock_event_mode mode,
struct clock_event_device *evdev)
{
switch (mode) {
case CLOCK_EVT_MODE_ONESHOT:
pr_debug("%s: start\n", evdev->name);
/* FALLTHROUGH */
case CLOCK_EVT_MODE_RESUME:
/*
* If we're using the COUNT and COMPARE registers we
* need to force idle poll.
*/
cpu_idle_poll_ctrl(true);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
sysreg_write(COMPARE, 0);
pr_debug("%s: stop\n", evdev->name);
cpu_idle_poll_ctrl(false);
break;
default:
BUG();
}
}
static struct clock_event_device comparator = {
.name = "avr32_comparator",
.features = CLOCK_EVT_FEAT_ONESHOT,
.shift = 16,
.rating = 50,
.set_next_event = comparator_next_event,
.set_mode = comparator_mode,
};
void read_persistent_clock(struct timespec *ts)
{
ts->tv_sec = mktime(2007, 1, 1, 0, 0, 0);
ts->tv_nsec = 0;
}
void __init time_init(void)
{
unsigned long counter_hz;
int ret;
/* figure rate for counter */
counter_hz = clk_get_rate(boot_cpu_data.clk);
ret = clocksource_register_hz(&counter, counter_hz);
if (ret)
pr_debug("timer: could not register clocksource: %d\n", ret);
/* setup COMPARE clockevent */
comparator.mult = div_sc(counter_hz, NSEC_PER_SEC, comparator.shift);
comparator.max_delta_ns = clockevent_delta2ns((u32)~0, &comparator);
comparator.min_delta_ns = clockevent_delta2ns(50, &comparator) + 1;
comparator.cpumask = cpumask_of(0);
sysreg_write(COMPARE, 0);
timer_irqaction.dev_id = &comparator;
ret = setup_irq(0, &timer_irqaction);
if (ret)
pr_debug("timer: could not request IRQ 0: %d\n", ret);
else {
clockevents_register_device(&comparator);
pr_info("%s: irq 0, %lu.%03lu MHz\n", comparator.name,
((counter_hz + 500) / 1000) / 1000,
((counter_hz + 500) / 1000) % 1000);
}
}
|
