1 #include <linux/types.h>
2 #include <linux/init.h>
3 #include <linux/kernel_stat.h>
4 #include <linux/sched.h>
5 #include <linux/spinlock.h>
6 #include <linux/interrupt.h>
7 #include <linux/mc146818rtc.h>
8 #include <linux/smp.h>
9 #include <linux/timex.h>
10 
11 #include <asm/hardirq.h>
12 #include <asm/div64.h>
13 #include <asm/cpu.h>
14 #include <asm/time.h>
15 #include <asm/irq.h>
16 #include <asm/mc146818-time.h>
17 #include <asm/msc01_ic.h>
18 
19 #include <asm/mips-boards/generic.h>
20 #include <asm/mips-boards/prom.h>
21 #include <asm/mips-boards/simint.h>
22 
23 
24 unsigned long cpu_khz;
25 
26 /*
27  * Estimate CPU frequency.  Sets mips_hpt_frequency as a side-effect
28  */
estimate_cpu_frequency(void)29 static unsigned int __init estimate_cpu_frequency(void)
30 {
31 	unsigned int prid = read_c0_prid() & 0xffff00;
32 	unsigned int count;
33 
34 #if 1
35 	/*
36 	 * hardwire the board frequency to 12MHz.
37 	 */
38 
39 	if ((prid == (PRID_COMP_MIPS | PRID_IMP_20KC)) ||
40 	    (prid == (PRID_COMP_MIPS | PRID_IMP_25KF)))
41 		count = 12000000;
42 	else
43 		count =  6000000;
44 #else
45 	unsigned int flags;
46 
47 	local_irq_save(flags);
48 
49 	/* Start counter exactly on falling edge of update flag */
50 	while (CMOS_READ(RTC_REG_A) & RTC_UIP);
51 	while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
52 
53 	/* Start r4k counter. */
54 	write_c0_count(0);
55 
56 	/* Read counter exactly on falling edge of update flag */
57 	while (CMOS_READ(RTC_REG_A) & RTC_UIP);
58 	while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
59 
60 	count = read_c0_count();
61 
62 	/* restore interrupts */
63 	local_irq_restore(flags);
64 #endif
65 
66 	mips_hpt_frequency = count;
67 
68 	if ((prid != (PRID_COMP_MIPS | PRID_IMP_20KC)) &&
69 	    (prid != (PRID_COMP_MIPS | PRID_IMP_25KF)))
70 		count *= 2;
71 
72 	count += 5000;    /* round */
73 	count -= count%10000;
74 
75 	return count;
76 }
77 
78 static int mips_cpu_timer_irq;
79 
mips_timer_dispatch(void)80 static void mips_timer_dispatch(void)
81 {
82 	do_IRQ(mips_cpu_timer_irq);
83 }
84 
85 
get_c0_compare_int(void)86 unsigned __cpuinit get_c0_compare_int(void)
87 {
88 #ifdef MSC01E_INT_BASE
89 	if (cpu_has_veic) {
90 		set_vi_handler(MSC01E_INT_CPUCTR, mips_timer_dispatch);
91 		mips_cpu_timer_irq = MSC01E_INT_BASE + MSC01E_INT_CPUCTR;
92 
93 		return mips_cpu_timer_irq;
94 	}
95 #endif
96 	if (cpu_has_vint)
97 		set_vi_handler(cp0_compare_irq, mips_timer_dispatch);
98 	mips_cpu_timer_irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
99 
100 	return mips_cpu_timer_irq;
101 }
102 
plat_time_init(void)103 void __init plat_time_init(void)
104 {
105 	unsigned int est_freq;
106 
107 	/* Set Data mode - binary. */
108 	CMOS_WRITE(CMOS_READ(RTC_CONTROL) | RTC_DM_BINARY, RTC_CONTROL);
109 
110 	est_freq = estimate_cpu_frequency();
111 
112 	printk(KERN_INFO "CPU frequency %d.%02d MHz\n", est_freq / 1000000,
113 	       (est_freq % 1000000) * 100 / 1000000);
114 
115 	cpu_khz = est_freq / 1000;
116 }
117