summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-netx/time.c
blob: e2346013e2273b9daafe57c8ab728e3bee1cb638 (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
/*
 * arch/arm/mach-netx/time.c
 *
 * Copyright (c) 2005 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
 *
 * 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.
 *
 * 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 <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <asm/mach/time.h>
#include <mach/netx-regs.h>

#define NETX_CLOCK_FREQ 100000000
#define NETX_LATCH DIV_ROUND_CLOSEST(NETX_CLOCK_FREQ, HZ)

#define TIMER_CLOCKEVENT 0
#define TIMER_CLOCKSOURCE 1

static void netx_set_mode(enum clock_event_mode mode,
		struct clock_event_device *clk)
{
	u32 tmode;

	/* disable timer */
	writel(0, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKEVENT));

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		writel(NETX_LATCH, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKEVENT));
		tmode = NETX_GPIO_COUNTER_CTRL_RST_EN |
			NETX_GPIO_COUNTER_CTRL_IRQ_EN |
			NETX_GPIO_COUNTER_CTRL_RUN;
		break;

	case CLOCK_EVT_MODE_ONESHOT:
		writel(0, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKEVENT));
		tmode = NETX_GPIO_COUNTER_CTRL_IRQ_EN |
			NETX_GPIO_COUNTER_CTRL_RUN;
		break;

	default:
		WARN(1, "%s: unhandled mode %d\n", __func__, mode);
		/* fall through */

	case CLOCK_EVT_MODE_SHUTDOWN:
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_RESUME:
		tmode = 0;
		break;
	}

	writel(tmode, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKEVENT));
}

static int netx_set_next_event(unsigned long evt,
		struct clock_event_device *clk)
{
	writel(0 - evt, NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKEVENT));
	return 0;
}

static struct clock_event_device netx_clockevent = {
	.name = "netx-timer" __stringify(TIMER_CLOCKEVENT),
	.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
	.set_next_event = netx_set_next_event,
	.set_mode = netx_set_mode,
};

/*
 * IRQ handler for the timer
 */
static irqreturn_t
netx_timer_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *evt = &netx_clockevent;

	/* acknowledge interrupt */
	writel(COUNTER_BIT(0), NETX_GPIO_IRQ);

	evt->event_handler(evt);

	return IRQ_HANDLED;
}

static struct irqaction netx_timer_irq = {
	.name		= "NetX Timer Tick",
	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
	.handler	= netx_timer_interrupt,
};

/*
 * Set up timer interrupt
 */
void __init netx_timer_init(void)
{
	/* disable timer initially */
	writel(0, NETX_GPIO_COUNTER_CTRL(0));

	/* Reset the timer value to zero */
	writel(0, NETX_GPIO_COUNTER_CURRENT(0));

	writel(NETX_LATCH, NETX_GPIO_COUNTER_MAX(0));

	/* acknowledge interrupt */
	writel(COUNTER_BIT(0), NETX_GPIO_IRQ);

	/* Enable the interrupt in the specific timer
	 * register and start timer
	 */
	writel(COUNTER_BIT(0), NETX_GPIO_IRQ_ENABLE);
	writel(NETX_GPIO_COUNTER_CTRL_IRQ_EN | NETX_GPIO_COUNTER_CTRL_RUN,
			NETX_GPIO_COUNTER_CTRL(0));

	setup_irq(NETX_IRQ_TIMER0, &netx_timer_irq);

	/* Setup timer one for clocksource */
	writel(0, NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKSOURCE));
	writel(0, NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKSOURCE));
	writel(0xffffffff, NETX_GPIO_COUNTER_MAX(TIMER_CLOCKSOURCE));

	writel(NETX_GPIO_COUNTER_CTRL_RUN,
			NETX_GPIO_COUNTER_CTRL(TIMER_CLOCKSOURCE));

	clocksource_mmio_init(NETX_GPIO_COUNTER_CURRENT(TIMER_CLOCKSOURCE),
		"netx_timer", NETX_CLOCK_FREQ, 200, 32, clocksource_mmio_readl_up);

	/* with max_delta_ns >= delta2ns(0x800) the system currently runs fine.
	 * Adding some safety ... */
	netx_clockevent.cpumask = cpumask_of(0);
	clockevents_config_and_register(&netx_clockevent, NETX_CLOCK_FREQ,
					0xa00, 0xfffffffe);
}