aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/mach-ks8695/time.c
blob: 426c97662f5b39372b3ab375ec51bc81b551b872 (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
164
165
166
167
168
169
170
171
172
173
/*
 * arch/arm/mach-ks8695/time.c
 *
 * Copyright (C) 2006 Ben Dooks <ben@simtec.co.uk>
 * Copyright (C) 2006 Simtec Electronics
 *
 * 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 <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/io.h>
#include <linux/clockchips.h>

#include <asm/mach/time.h>
#include <asm/system_misc.h>

#include <mach/regs-irq.h>

#include "generic.h"

#define KS8695_TMR_OFFSET	(0xF0000 + 0xE400)
#define KS8695_TMR_VA		(KS8695_IO_VA + KS8695_TMR_OFFSET)
#define KS8695_TMR_PA		(KS8695_IO_PA + KS8695_TMR_OFFSET)

/*
 * Timer registers
 */
#define KS8695_TMCON		(0x00)		/* Timer Control Register */
#define KS8695_T1TC		(0x04)		/* Timer 1 Timeout Count Register */
#define KS8695_T0TC		(0x08)		/* Timer 0 Timeout Count Register */
#define KS8695_T1PD		(0x0C)		/* Timer 1 Pulse Count Register */
#define KS8695_T0PD		(0x10)		/* Timer 0 Pulse Count Register */

/* Timer Control Register */
#define TMCON_T1EN		(1 << 1)	/* Timer 1 Enable */
#define TMCON_T0EN		(1 << 0)	/* Timer 0 Enable */

/* Timer0 Timeout Counter Register */
#define T0TC_WATCHDOG		(0xff)		/* Enable watchdog mode */

static void ks8695_set_mode(enum clock_event_mode mode,
			    struct clock_event_device *evt)
{
	u32 tmcon;

	if (mode == CLOCK_EVT_FEAT_PERIODIC) {
		u32 rate = DIV_ROUND_CLOSEST(KS8695_CLOCK_RATE, HZ);
		u32 half = DIV_ROUND_CLOSEST(rate, 2);

		/* Disable timer 1 */
		tmcon = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON);
		tmcon &= ~TMCON_T1EN;
		writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);

		/* Both registers need to count down */
		writel_relaxed(half, KS8695_TMR_VA + KS8695_T1TC);
		writel_relaxed(half, KS8695_TMR_VA + KS8695_T1PD);

		/* Re-enable timer1 */
		tmcon |= TMCON_T1EN;
		writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);
	}
}

static int ks8695_set_next_event(unsigned long cycles,
				 struct clock_event_device *evt)

{
	u32 half = DIV_ROUND_CLOSEST(cycles, 2);
	u32 tmcon;

	/* Disable timer 1 */
	tmcon = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON);
	tmcon &= ~TMCON_T1EN;
	writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);

	/* Both registers need to count down */
	writel_relaxed(half, KS8695_TMR_VA + KS8695_T1TC);
	writel_relaxed(half, KS8695_TMR_VA + KS8695_T1PD);

	/* Re-enable timer1 */
	tmcon |= TMCON_T1EN;
	writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);

	return 0;
}

static struct clock_event_device clockevent_ks8695 = {
	.name		= "ks8695_t1tc",
	.rating		= 300, /* Reasonably fast and accurate clock event */
	.features	= CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
	.set_next_event	= ks8695_set_next_event,
	.set_mode	= ks8695_set_mode,
};

/*
 * IRQ handler for the timer.
 */
static irqreturn_t ks8695_timer_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *evt = &clockevent_ks8695;

	evt->event_handler(evt);
	return IRQ_HANDLED;
}

static struct irqaction ks8695_timer_irq = {
	.name		= "ks8695_tick",
	.flags		= IRQF_DISABLED | IRQF_TIMER,
	.handler	= ks8695_timer_interrupt,
};

static void ks8695_timer_setup(void)
{
	unsigned long tmcon;

	/* Disable timer 0 and 1 */
	tmcon = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON);
	tmcon &= ~TMCON_T0EN;
	tmcon &= ~TMCON_T1EN;
	writel_relaxed(tmcon, KS8695_TMR_VA + KS8695_TMCON);

	/*
	 * Use timer 1 to fire IRQs on the timeline, minimum 2 cycles
	 * (one on each counter) maximum 2*2^32, but the API will only
	 * accept up to a 32bit full word (0xFFFFFFFFU).
	 */
	clockevents_config_and_register(&clockevent_ks8695,
					KS8695_CLOCK_RATE, 2,
					0xFFFFFFFFU);
}

void __init ks8695_timer_init(void)
{
	ks8695_timer_setup();

	/* Enable timer interrupts */
	setup_irq(KS8695_IRQ_TIMER1, &ks8695_timer_irq);
}

void ks8695_restart(enum reboot_mode reboot_mode, const char *cmd)
{
	unsigned int reg;

	if (reboot_mode == REBOOT_SOFT)
		soft_restart(0);

	/* disable timer0 */
	reg = readl_relaxed(KS8695_TMR_VA + KS8695_TMCON);
	writel_relaxed(reg & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);

	/* enable watchdog mode */
	writel_relaxed((10 << 8) | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);

	/* re-enable timer0 */
	writel_relaxed(reg | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
}