aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/cpu/arm926ejs/spear/timer.c
blob: cbef34fab5c5645304115cbef31444b0efb659d4 (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
131
132
133
134
135
136
137
138
139
140
141
142
143
144
/*
 * (C) Copyright 2009
 * Vipin Kumar, ST Micoelectronics, vipin.kumar@st.com.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <asm/io.h>
#include <asm/arch/hardware.h>
#include <asm/arch/spr_gpt.h>
#include <asm/arch/spr_misc.h>

#define GPT_RESOLUTION	(CONFIG_SPEAR_HZ_CLOCK / CONFIG_SPEAR_HZ)
#define READ_TIMER()	(readl(&gpt_regs_p->count) & GPT_FREE_RUNNING)

static struct gpt_regs *const gpt_regs_p =
    (struct gpt_regs *)CONFIG_SPEAR_TIMERBASE;

static struct misc_regs *const misc_regs_p =
    (struct misc_regs *)CONFIG_SPEAR_MISCBASE;

DECLARE_GLOBAL_DATA_PTR;

#define timestamp gd->tbl
#define lastdec gd->lastinc

int timer_init(void)
{
	u32 synth;

	/* Prescaler setting */
#if defined(CONFIG_SPEAR3XX)
	writel(MISC_PRSC_CFG, &misc_regs_p->prsc2_clk_cfg);
	synth = MISC_GPT4SYNTH;
#elif defined(CONFIG_SPEAR600)
	writel(MISC_PRSC_CFG, &misc_regs_p->prsc1_clk_cfg);
	synth = MISC_GPT3SYNTH;
#else
# error Incorrect config. Can only be spear{600|300|310|320}
#endif

	writel(readl(&misc_regs_p->periph_clk_cfg) | synth,
	       &misc_regs_p->periph_clk_cfg);

	/* disable timers */
	writel(GPT_PRESCALER_1 | GPT_MODE_AUTO_RELOAD, &gpt_regs_p->control);

	/* load value for free running */
	writel(GPT_FREE_RUNNING, &gpt_regs_p->compare);

	/* auto reload, start timer */
	writel(readl(&gpt_regs_p->control) | GPT_ENABLE, &gpt_regs_p->control);

	reset_timer_masked();

	return 0;
}

/*
 * timer without interrupts
 */
ulong get_timer(ulong base)
{
	return (get_timer_masked() / GPT_RESOLUTION) - base;
}

void __udelay(unsigned long usec)
{
	ulong tmo;
	ulong start = get_timer_masked();
	ulong tenudelcnt = CONFIG_SPEAR_HZ_CLOCK / (1000 * 100);
	ulong rndoff;

	rndoff = (usec % 10) ? 1 : 0;

	/* tenudelcnt timer tick gives 10 microsecconds delay */
	tmo = ((usec / 10) + rndoff) * tenudelcnt;

	while ((ulong) (get_timer_masked() - start) < tmo)
		;
}

void reset_timer_masked(void)
{
	/* reset time */
	lastdec = READ_TIMER();
	timestamp = 0;
}

ulong get_timer_masked(void)
{
	ulong now = READ_TIMER();

	if (now >= lastdec) {
		/* normal mode */
		timestamp += now - lastdec;
	} else {
		/* we have an overflow ... */
		timestamp += now + GPT_FREE_RUNNING - lastdec;
	}
	lastdec = now;

	return timestamp;
}

void udelay_masked(unsigned long usec)
{
	return udelay(usec);
}

/*
 * This function is derived from PowerPC code (read timebase as long long).
 * On ARM it just returns the timer value.
 */
unsigned long long get_ticks(void)
{
	return get_timer(0);
}

/*
 * This function is derived from PowerPC code (timebase clock frequency).
 * On ARM it returns the number of timer ticks per second.
 */
ulong get_tbclk(void)
{
	return CONFIG_SPEAR_HZ;
}