summaryrefslogtreecommitdiffstats
path: root/arch/mips/mipssim/sim_time.c
blob: e7fa0d1078a383685e16abe15d7876a441f7bddf (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
#include <linux/types.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/mc146818rtc.h>
#include <linux/smp.h>
#include <linux/timex.h>

#include <asm/hardirq.h>
#include <asm/div64.h>
#include <asm/cpu.h>
#include <asm/time.h>
#include <asm/irq.h>
#include <asm/mc146818-time.h>
#include <asm/msc01_ic.h>

#include <asm/mips-boards/generic.h>
#include <asm/mips-boards/prom.h>
#include <asm/mips-boards/simint.h>


unsigned long cpu_khz;

/*
 * Estimate CPU frequency.  Sets mips_hpt_frequency as a side-effect
 */
static unsigned int __init estimate_cpu_frequency(void)
{
	unsigned int prid = read_c0_prid() & 0xffff00;
	unsigned int count;

#if 1
	/*
	 * hardwire the board frequency to 12MHz.
	 */

	if ((prid == (PRID_COMP_MIPS | PRID_IMP_20KC)) ||
	    (prid == (PRID_COMP_MIPS | PRID_IMP_25KF)))
		count = 12000000;
	else
		count =  6000000;
#else
	unsigned int flags;

	local_irq_save(flags);

	/* Start counter exactly on falling edge of update flag */
	while (CMOS_READ(RTC_REG_A) & RTC_UIP);
	while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));

	/* Start r4k counter. */
	write_c0_count(0);

	/* Read counter exactly on falling edge of update flag */
	while (CMOS_READ(RTC_REG_A) & RTC_UIP);
	while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));

	count = read_c0_count();

	/* restore interrupts */
	local_irq_restore(flags);
#endif

	mips_hpt_frequency = count;

	if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
	    (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
		count *= 2;

	count += 5000;    /* round */
	count -= count%10000;

	return count;
}

void __init plat_time_init(void)
{
	unsigned int est_freq, flags;

	local_irq_save(flags);

	/* Set Data mode - binary. */
	CMOS_WRITE(CMOS_READ(RTC_CONTROL) | RTC_DM_BINARY, RTC_CONTROL);

	est_freq = estimate_cpu_frequency();

	printk(KERN_INFO "CPU frequency %d.%02d MHz\n", est_freq / 1000000,
	       (est_freq % 1000000) * 100 / 1000000);

	cpu_khz = est_freq / 1000;

	local_irq_restore(flags);
}

static int mips_cpu_timer_irq;

static void mips_timer_dispatch(void)
{
	do_IRQ(mips_cpu_timer_irq);
}


void __init plat_timer_setup(struct irqaction *irq)
{
	if (cpu_has_veic) {
		set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
		mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
	} else {
		if (cpu_has_vint)
			set_vi_handler(cp0_compare_irq, mips_timer_dispatch);
		mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
	}

	/* we are using the cpu counter for timer interrupts */
	setup_irq(mips_cpu_timer_irq, irq);

#ifdef CONFIG_SMP
	/* irq_desc(riptor) is a global resource, when the interrupt overlaps
	   on seperate cpu's the first one tries to handle the second interrupt.
	   The effect is that the int remains disabled on the second cpu.
	   Mark the interrupt with IRQ_PER_CPU to avoid any confusion */
	irq_desc[mips_cpu_timer_irq].flags |= IRQ_PER_CPU;
	set_irq_handler(mips_cpu_timer_irq, handle_percpu_irq);
#endif
}
OpenPOWER on IntegriCloud