summaryrefslogtreecommitdiffstats
path: root/arch/m68knommu/platform/coldfire/timers.c
blob: 60242f65fea90a3df427d9fca7158cd37b45fb89 (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
174
/***************************************************************************/

/*
 *	timers.c -- generic ColdFire hardware timer support.
 *
 *	Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com>
 */

/***************************************************************************/

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/profile.h>
#include <linux/clocksource.h>
#include <asm/io.h>
#include <asm/traps.h>
#include <asm/machdep.h>
#include <asm/coldfire.h>
#include <asm/mcftimer.h>
#include <asm/mcfsim.h>

/***************************************************************************/

/*
 *	By default use timer1 as the system clock timer.
 */
#define	FREQ	(MCF_BUSCLK / 16)
#define	TA(a)	(MCFTIMER_BASE1 + (a))

/*
 *	These provide the underlying interrupt vector support.
 *	Unfortunately it is a little different on each ColdFire.
 */
void coldfire_profile_init(void);

#if defined(CONFIG_M532x)
#define	__raw_readtrr	__raw_readl
#define	__raw_writetrr	__raw_writel
#else
#define	__raw_readtrr	__raw_readw
#define	__raw_writetrr	__raw_writew
#endif

static u32 mcftmr_cycles_per_jiffy;
static u32 mcftmr_cnt;

/***************************************************************************/

static irqreturn_t mcftmr_tick(int irq, void *dummy)
{
	/* Reset the ColdFire timer */
	__raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));

	mcftmr_cnt += mcftmr_cycles_per_jiffy;
	return arch_timer_interrupt(irq, dummy);
}

/***************************************************************************/

static struct irqaction mcftmr_timer_irq = {
	.name	 = "timer",
	.flags	 = IRQF_DISABLED | IRQF_TIMER,
	.handler = mcftmr_tick,
};

/***************************************************************************/

static cycle_t mcftmr_read_clk(struct clocksource *cs)
{
	unsigned long flags;
	u32 cycles;
	u16 tcn;

	local_irq_save(flags);
	tcn = __raw_readw(TA(MCFTIMER_TCN));
	cycles = mcftmr_cnt;
	local_irq_restore(flags);

	return cycles + tcn;
}

/***************************************************************************/

static struct clocksource mcftmr_clk = {
	.name	= "tmr",
	.rating	= 250,
	.read	= mcftmr_read_clk,
	.shift	= 20,
	.mask	= CLOCKSOURCE_MASK(32),
	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
};

/***************************************************************************/

void hw_timer_init(void)
{
	__raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
	mcftmr_cycles_per_jiffy = FREQ / HZ;
	/*
	 *	The coldfire timer runs from 0 to TRR included, then 0
	 *	again and so on.  It counts thus actually TRR + 1 steps
	 *	for 1 tick, not TRR.  So if you want n cycles,
	 *	initialize TRR with n - 1.
	 */
	__raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR));
	__raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
		MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));

	mcftmr_clk.mult = clocksource_hz2mult(FREQ, mcftmr_clk.shift);
	clocksource_register(&mcftmr_clk);

	setup_irq(MCF_IRQ_TIMER, &mcftmr_timer_irq);

#ifdef CONFIG_HIGHPROFILE
	coldfire_profile_init();
#endif
}

/***************************************************************************/
#ifdef CONFIG_HIGHPROFILE
/***************************************************************************/

/*
 *	By default use timer2 as the profiler clock timer.
 */
#define	PA(a)	(MCFTIMER_BASE2 + (a))

/*
 *	Choose a reasonably fast profile timer. Make it an odd value to
 *	try and get good coverage of kernel operations.
 */
#define	PROFILEHZ	1013

/*
 *	Use the other timer to provide high accuracy profiling info.
 */
irqreturn_t coldfire_profile_tick(int irq, void *dummy)
{
	/* Reset ColdFire timer2 */
	__raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
	if (current->pid)
		profile_tick(CPU_PROFILING);
	return IRQ_HANDLED;
}

/***************************************************************************/

static struct irqaction coldfire_profile_irq = {
	.name	 = "profile timer",
	.flags	 = IRQF_DISABLED | IRQF_TIMER,
	.handler = coldfire_profile_tick,
};

void coldfire_profile_init(void)
{
	printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n",
	       PROFILEHZ);

	/* Set up TIMER 2 as high speed profile clock */
	__raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));

	__raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
	__raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
		MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));

	setup_irq(MCF_IRQ_PROFILER, &coldfire_profile_irq);
}

/***************************************************************************/
#endif	/* CONFIG_HIGHPROFILE */
/***************************************************************************/
OpenPOWER on IntegriCloud