summaryrefslogtreecommitdiff
path: root/arch/arm/cpu/arm920t/a320/timer.c
blob: 512fb9d73db8dfb7cf7331c914ff62c84c84b19d (plain)
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
/*
 * (C) Copyright 2009 Faraday Technology
 * Po-Yu Chuang <ratbert@faraday-tech.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <common.h>
#include <div64.h>
#include <asm/io.h>
#include <faraday/ftpmu010.h>
#include <faraday/fttmr010.h>

DECLARE_GLOBAL_DATA_PTR;

#define TIMER_CLOCK	32768
#define TIMER_LOAD_VAL	0xffffffff

static inline unsigned long long tick_to_time(unsigned long long tick)
{
	tick *= CONFIG_SYS_HZ;
	do_div(tick, gd->arch.timer_rate_hz);

	return tick;
}

static inline unsigned long long usec_to_tick(unsigned long long usec)
{
	usec *= gd->arch.timer_rate_hz;
	do_div(usec, 1000000);

	return usec;
}

int timer_init(void)
{
	struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
	unsigned int cr;

	debug("%s()\n", __func__);

	/* disable timers */
	writel(0, &tmr->cr);

	/* use 32768Hz oscillator for RTC, WDT, TIMER */
	ftpmu010_32768osc_enable();

	/* setup timer */
	writel(TIMER_LOAD_VAL, &tmr->timer3_load);
	writel(TIMER_LOAD_VAL, &tmr->timer3_counter);
	writel(0, &tmr->timer3_match1);
	writel(0, &tmr->timer3_match2);

	/* we don't want timer to issue interrupts */
	writel(FTTMR010_TM3_MATCH1 |
	       FTTMR010_TM3_MATCH2 |
	       FTTMR010_TM3_OVERFLOW,
	       &tmr->interrupt_mask);

	cr = readl(&tmr->cr);
	cr |= FTTMR010_TM3_CLOCK;	/* use external clock */
	cr |= FTTMR010_TM3_ENABLE;
	writel(cr, &tmr->cr);

	gd->arch.timer_rate_hz = TIMER_CLOCK;
	gd->arch.tbu = gd->arch.tbl = 0;

	return 0;
}

/*
 * Get the current 64 bit timer tick count
 */
unsigned long long get_ticks(void)
{
	struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
	ulong now = TIMER_LOAD_VAL - readl(&tmr->timer3_counter);

	/* increment tbu if tbl has rolled over */
	if (now < gd->arch.tbl)
		gd->arch.tbu++;
	gd->arch.tbl = now;
	return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
}

void __udelay(unsigned long usec)
{
	unsigned long long start;
	ulong tmo;

	start = get_ticks();		/* get current timestamp */
	tmo = usec_to_tick(usec);	/* convert usecs to ticks */
	while ((get_ticks() - start) < tmo)
		;			/* loop till time has passed */
}

/*
 * get_timer(base) can be used to check for timeouts or
 * to measure elasped time relative to an event:
 *
 * ulong start_time = get_timer(0) sets start_time to the current
 * time value.
 * get_timer(start_time) returns the time elapsed since then.
 *
 * The time is used in CONFIG_SYS_HZ units!
 */
ulong get_timer(ulong base)
{
	return tick_to_time(get_ticks()) - base;
}

/*
 * Return the number of timer ticks per second.
 */
ulong get_tbclk(void)
{
	return gd->arch.timer_rate_hz;
}