summaryrefslogtreecommitdiffstats
path: root/arch/unicore32/kernel/time.c
blob: ac4c5449bb88dad90a1f194088f84d724aa4c622 (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
/*
 * linux/arch/unicore32/kernel/time.c
 *
 * Code specific to PKUnity SoC and UniCore ISA
 *
 *	Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
 *	Copyright (C) 2001-2010 Guan Xuetao
 *
 * 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/init.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/timex.h>
#include <linux/clockchips.h>

#include <mach/hardware.h>

#define MIN_OSCR_DELTA 2

static irqreturn_t puv3_ost0_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *c = dev_id;

	/* Disarm the compare/match, signal the event. */
	writel(readl(OST_OIER) & ~OST_OIER_E0, OST_OIER);
	writel(readl(OST_OSSR) & ~OST_OSSR_M0, OST_OSSR);
	c->event_handler(c);

	return IRQ_HANDLED;
}

static int
puv3_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c)
{
	unsigned long next, oscr;

	writel(readl(OST_OIER) | OST_OIER_E0, OST_OIER);
	next = readl(OST_OSCR) + delta;
	writel(next, OST_OSMR0);
	oscr = readl(OST_OSCR);

	return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
}

static int puv3_osmr0_shutdown(struct clock_event_device *evt)
{
	writel(readl(OST_OIER) & ~OST_OIER_E0, OST_OIER);
	writel(readl(OST_OSSR) & ~OST_OSSR_M0, OST_OSSR);
	return 0;
}

static struct clock_event_device ckevt_puv3_osmr0 = {
	.name			= "osmr0",
	.features		= CLOCK_EVT_FEAT_ONESHOT,
	.rating			= 200,
	.set_next_event		= puv3_osmr0_set_next_event,
	.set_state_shutdown	= puv3_osmr0_shutdown,
	.set_state_oneshot	= puv3_osmr0_shutdown,
};

static cycle_t puv3_read_oscr(struct clocksource *cs)
{
	return readl(OST_OSCR);
}

static struct clocksource cksrc_puv3_oscr = {
	.name		= "oscr",
	.rating		= 200,
	.read		= puv3_read_oscr,
	.mask		= CLOCKSOURCE_MASK(32),
	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
};

static struct irqaction puv3_timer_irq = {
	.name		= "ost0",
	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
	.handler	= puv3_ost0_interrupt,
	.dev_id		= &ckevt_puv3_osmr0,
};

void __init time_init(void)
{
	writel(0, OST_OIER);		/* disable any timer interrupts */
	writel(0, OST_OSSR);		/* clear status on all timers */

	clockevents_calc_mult_shift(&ckevt_puv3_osmr0, CLOCK_TICK_RATE, 5);

	ckevt_puv3_osmr0.max_delta_ns =
		clockevent_delta2ns(0x7fffffff, &ckevt_puv3_osmr0);
	ckevt_puv3_osmr0.min_delta_ns =
		clockevent_delta2ns(MIN_OSCR_DELTA * 2, &ckevt_puv3_osmr0) + 1;
	ckevt_puv3_osmr0.cpumask = cpumask_of(0);

	setup_irq(IRQ_TIMER0, &puv3_timer_irq);

	clocksource_register_hz(&cksrc_puv3_oscr, CLOCK_TICK_RATE);
	clockevents_register_device(&ckevt_puv3_osmr0);
}

#ifdef CONFIG_PM
unsigned long osmr[4], oier;

void puv3_timer_suspend(void)
{
	osmr[0] = readl(OST_OSMR0);
	osmr[1] = readl(OST_OSMR1);
	osmr[2] = readl(OST_OSMR2);
	osmr[3] = readl(OST_OSMR3);
	oier = readl(OST_OIER);
}

void puv3_timer_resume(void)
{
	writel(0, OST_OSSR);
	writel(osmr[0], OST_OSMR0);
	writel(osmr[1], OST_OSMR1);
	writel(osmr[2], OST_OSMR2);
	writel(osmr[3], OST_OSMR3);
	writel(oier, OST_OIER);

	/*
	 * OSMR0 is the system timer: make sure OSCR is sufficiently behind
	 */
	writel(readl(OST_OSMR0) - LATCH, OST_OSCR);
}
#else
void puv3_timer_suspend(void) { };
void puv3_timer_resume(void) { };
#endif