summaryrefslogtreecommitdiff
path: root/arch/arm/cpu/armv7/zynq/timer.c
blob: 636322a8e5728de647c8a333b0a2feb9b1b730ed (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
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
/*
 * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
 *
 * (C) Copyright 2008
 * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
 *
 * (C) Copyright 2004
 * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
 *
 * (C) Copyright 2002-2004
 * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
 *
 * (C) Copyright 2003
 * Texas Instruments <www.ti.com>
 *
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Marius Groeger <mgroeger@sysgo.de>
 *
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Alex Zuepke <azu@sysgo.de>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <div64.h>
#include <asm/io.h>
#include <asm/arch/hardware.h>

DECLARE_GLOBAL_DATA_PTR;

struct scu_timer {
	u32 load; /* Timer Load Register */
	u32 counter; /* Timer Counter Register */
	u32 control; /* Timer Control Register */
};

static struct scu_timer *timer_base =
			      (struct scu_timer *)ZYNQ_SCUTIMER_BASEADDR;

#define SCUTIMER_CONTROL_PRESCALER_MASK	0x0000FF00 /* Prescaler */
#define SCUTIMER_CONTROL_PRESCALER_SHIFT	8
#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK	0x00000002 /* Auto-reload */
#define SCUTIMER_CONTROL_ENABLE_MASK		0x00000001 /* Timer enable */

#define TIMER_LOAD_VAL 0xFFFFFFFF
#define TIMER_PRESCALE 255
#define TIMER_TICK_HZ  (CONFIG_CPU_FREQ_HZ / 2 / TIMER_PRESCALE)

int timer_init(void)
{
	const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
			(TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
			SCUTIMER_CONTROL_ENABLE_MASK;

	/* Load the timer counter register */
	writel(0xFFFFFFFF, &timer_base->load);

	/*
	 * Start the A9Timer device
	 * Enable Auto reload mode, Clear prescaler control bits
	 * Set prescaler value, Enable the decrementer
	 */
	clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK,
								emask);

	/* Reset time */
	gd->arch.lastinc = readl(&timer_base->counter) /
					(TIMER_TICK_HZ / CONFIG_SYS_HZ);
	gd->arch.tbl = 0;

	return 0;
}

/*
 * This function is derived from PowerPC code (read timebase as long long).
 * On ARM it just returns the timer value.
 */
ulong get_timer_masked(void)
{
	ulong now;

	now = readl(&timer_base->counter) / (TIMER_TICK_HZ / CONFIG_SYS_HZ);

	if (gd->arch.lastinc >= now) {
		/* Normal mode */
		gd->arch.tbl += gd->arch.lastinc - now;
	} else {
		/* We have an overflow ... */
		gd->arch.tbl += gd->arch.lastinc + TIMER_LOAD_VAL - now;
	}
	gd->arch.lastinc = now;

	return gd->arch.tbl;
}

void __udelay(unsigned long usec)
{
	u32 countticks;
	u32 timeend;
	u32 timediff;
	u32 timenow;

	if (usec == 0)
		return;

	countticks = (u32) (((unsigned long long) TIMER_TICK_HZ * usec) /
								1000000);

	/* decrementing timer */
	timeend = readl(&timer_base->counter) - countticks;

#if TIMER_LOAD_VAL != 0xFFFFFFFF
	/* do not manage multiple overflow */
	if (countticks >= TIMER_LOAD_VAL)
		countticks = TIMER_LOAD_VAL - 1;
#endif

	do {
		timenow = readl(&timer_base->counter);

		if (timenow >= timeend) {
			/* normal case */
			timediff = timenow - timeend;
		} else {
			if ((TIMER_LOAD_VAL - timeend + timenow) <=
								countticks) {
				/* overflow */
				timediff = TIMER_LOAD_VAL - timeend + timenow;
			} else {
				/* missed the exact match */
				break;
			}
		}
	} while (timediff > 0);
}

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

/*
 * 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_SYS_HZ;
}