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
|
/*
* linux/arch/arm/mach-imx/time.c
*
* Copyright (C) 2000-2001 Deep Blue Solutions
* Copyright (C) 2002 Shane Nay (shane@minirl.com)
*
* 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/kernel.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/time.h>
#include <linux/clocksource.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/leds.h>
#include <asm/irq.h>
#include <asm/mach/time.h>
/* Use timer 1 as system timer */
#define TIMER_BASE IMX_TIM1_BASE
static unsigned long evt_diff;
/*
* IRQ handler for the timer
*/
static irqreturn_t
imx_timer_interrupt(int irq, void *dev_id)
{
uint32_t tstat;
/* clear the interrupt */
tstat = IMX_TSTAT(TIMER_BASE);
IMX_TSTAT(TIMER_BASE) = 0;
if (tstat & TSTAT_COMP) {
do {
write_seqlock(&xtime_lock);
timer_tick();
write_sequnlock(&xtime_lock);
IMX_TCMP(TIMER_BASE) += evt_diff;
} while (unlikely((int32_t)(IMX_TCMP(TIMER_BASE)
- IMX_TCN(TIMER_BASE)) < 0));
}
return IRQ_HANDLED;
}
static struct irqaction imx_timer_irq = {
.name = "i.MX Timer Tick",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = imx_timer_interrupt,
};
/*
* Set up timer hardware into expected mode and state.
*/
static void __init imx_timer_hardware_init(void)
{
/*
* Initialise to a known state (all timers off, and timing reset)
*/
IMX_TCTL(TIMER_BASE) = 0;
IMX_TPRER(TIMER_BASE) = 0;
IMX_TCMP(TIMER_BASE) = LATCH - 1;
IMX_TCTL(TIMER_BASE) = TCTL_FRR | TCTL_CLK_PCLK1 | TCTL_IRQEN | TCTL_TEN;
evt_diff = LATCH;
}
cycle_t imx_get_cycles(void)
{
return IMX_TCN(TIMER_BASE);
}
static struct clocksource clocksource_imx = {
.name = "imx_timer1",
.rating = 200,
.read = imx_get_cycles,
.mask = 0xFFFFFFFF,
.shift = 20,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static int __init imx_clocksource_init(void)
{
clocksource_imx.mult =
clocksource_hz2mult(imx_get_perclk1(), clocksource_imx.shift);
clocksource_register(&clocksource_imx);
return 0;
}
static void __init imx_timer_init(void)
{
imx_timer_hardware_init();
imx_clocksource_init();
/*
* Make irqs happen for the system timer
*/
setup_irq(TIM1_INT, &imx_timer_irq);
}
struct sys_timer imx_timer = {
.init = imx_timer_init,
};
|
