aboutsummaryrefslogtreecommitdiff
path: root/arch/mips/sgi-ip22/ip22-time.c
blob: 0bae605201c406bf8774753e77ffe1256a8a4838 (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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Time operations for IP22 machines. Original code may come from
 * Ralf Baechle or David S. Miller (sorry guys, i'm really not sure)
 *
 * Copyright (C) 2001 by Ladislav Michl
 * Copyright (C) 2003 Ralf Baechle (ralf@linux-mips.org)
 */
#include <linux/bcd.h>
#include <linux/ds1286.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/time.h>

#include <asm/cpu.h>
#include <asm/mipsregs.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/time.h>
#include <asm/sgialib.h>
#include <asm/sgi/ioc.h>
#include <asm/sgi/hpc3.h>
#include <asm/sgi/ip22.h>

/*
 * note that mktime uses month from 1 to 12 while to_tm
 * uses 0 to 11.
 */
static unsigned long indy_rtc_get_time(void)
{
	unsigned int yrs, mon, day, hrs, min, sec;
	unsigned int save_control;
	unsigned long flags;

	spin_lock_irqsave(&rtc_lock, flags);
	save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff;
	hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE;

	sec = BCD2BIN(hpc3c0->rtcregs[RTC_SECONDS] & 0xff);
	min = BCD2BIN(hpc3c0->rtcregs[RTC_MINUTES] & 0xff);
	hrs = BCD2BIN(hpc3c0->rtcregs[RTC_HOURS] & 0x3f);
	day = BCD2BIN(hpc3c0->rtcregs[RTC_DATE] & 0xff);
	mon = BCD2BIN(hpc3c0->rtcregs[RTC_MONTH] & 0x1f);
	yrs = BCD2BIN(hpc3c0->rtcregs[RTC_YEAR] & 0xff);

	hpc3c0->rtcregs[RTC_CMD] = save_control;
	spin_unlock_irqrestore(&rtc_lock, flags);

	if (yrs < 45)
		yrs += 30;
	if ((yrs += 40) < 70)
		yrs += 100;

	return mktime(yrs + 1900, mon, day, hrs, min, sec);
}

static int indy_rtc_set_time(unsigned long tim)
{
	struct rtc_time tm;
	unsigned int save_control;
	unsigned long flags;

	to_tm(tim, &tm);

	tm.tm_mon += 1;		/* tm_mon starts at zero */
	tm.tm_year -= 1940;
	if (tm.tm_year >= 100)
		tm.tm_year -= 100;

	spin_lock_irqsave(&rtc_lock, flags);
	save_control = hpc3c0->rtcregs[RTC_CMD] & 0xff;
	hpc3c0->rtcregs[RTC_CMD] = save_control | RTC_TE;

	hpc3c0->rtcregs[RTC_YEAR] = BIN2BCD(tm.tm_sec);
	hpc3c0->rtcregs[RTC_MONTH] = BIN2BCD(tm.tm_mon);
	hpc3c0->rtcregs[RTC_DATE] = BIN2BCD(tm.tm_mday);
	hpc3c0->rtcregs[RTC_HOURS] = BIN2BCD(tm.tm_hour);
	hpc3c0->rtcregs[RTC_MINUTES] = BIN2BCD(tm.tm_min);
	hpc3c0->rtcregs[RTC_SECONDS] = BIN2BCD(tm.tm_sec);
	hpc3c0->rtcregs[RTC_HUNDREDTH_SECOND] = 0;

	hpc3c0->rtcregs[RTC_CMD] = save_control;
	spin_unlock_irqrestore(&rtc_lock, flags);

	return 0;
}

static unsigned long dosample(void)
{
	u32 ct0, ct1;
	volatile u8 msb, lsb;

	/* Start the counter. */
	sgint->tcword = (SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL |
			 SGINT_TCWORD_MRGEN);
	sgint->tcnt2 = SGINT_TCSAMP_COUNTER & 0xff;
	sgint->tcnt2 = SGINT_TCSAMP_COUNTER >> 8;

	/* Get initial counter invariant */
	ct0 = read_c0_count();

	/* Latch and spin until top byte of counter2 is zero */
	do {
		sgint->tcword = SGINT_TCWORD_CNT2 | SGINT_TCWORD_CLAT;
		lsb = sgint->tcnt2;
		msb = sgint->tcnt2;
		ct1 = read_c0_count();
	} while (msb);

	/* Stop the counter. */
	sgint->tcword = (SGINT_TCWORD_CNT2 | SGINT_TCWORD_CALL |
			 SGINT_TCWORD_MSWST);
	/*
	 * Return the difference, this is how far the r4k counter increments
	 * for every 1/HZ seconds. We round off the nearest 1 MHz of master
	 * clock (= 1000000 / HZ / 2).
	 */
	/*return (ct1 - ct0 + (500000/HZ/2)) / (500000/HZ) * (500000/HZ);*/
	return (ct1 - ct0) / (500000/HZ) * (500000/HZ);
}

/*
 * Here we need to calibrate the cycle counter to at least be close.
 */
static __init void indy_time_init(void)
{
	unsigned long r4k_ticks[3];
	unsigned long r4k_tick;

	/*
	 * Figure out the r4k offset, the algorithm is very simple and works in
	 * _all_ cases as long as the 8254 counter register itself works ok (as
	 * an interrupt driving timer it does not because of bug, this is why
	 * we are using the onchip r4k counter/compare register to serve this
	 * purpose, but for r4k_offset calculation it will work ok for us).
	 * There are other very complicated ways of performing this calculation
	 * but this one works just fine so I am not going to futz around. ;-)
	 */
	printk(KERN_INFO "Calibrating system timer... ");
	dosample();	/* Prime cache. */
	dosample();	/* Prime cache. */
	/* Zero is NOT an option. */
	do {
		r4k_ticks[0] = dosample();
	} while (!r4k_ticks[0]);
	do {
		r4k_ticks[1] = dosample();
	} while (!r4k_ticks[1]);

	if (r4k_ticks[0] != r4k_ticks[1]) {
		printk("warning: timer counts differ, retrying... ");
		r4k_ticks[2] = dosample();
		if (r4k_ticks[2] == r4k_ticks[0]
		    || r4k_ticks[2] == r4k_ticks[1])
			r4k_tick = r4k_ticks[2];
		else {
			printk("disagreement, using average... ");
			r4k_tick = (r4k_ticks[0] + r4k_ticks[1]
				   + r4k_ticks[2]) / 3;
		}
	} else
		r4k_tick = r4k_ticks[0];

	printk("%d [%d.%04d MHz CPU]\n", (int) r4k_tick,
		(int) (r4k_tick / (500000 / HZ)),
		(int) (r4k_tick % (500000 / HZ)));

	mips_hpt_frequency = r4k_tick * HZ;
}

/* Generic SGI handler for (spurious) 8254 interrupts */
void indy_8254timer_irq(struct pt_regs *regs)
{
	int irq = SGI_8254_0_IRQ;
	ULONG cnt;
	char c;

	irq_enter();
	kstat_this_cpu.irqs[irq]++;
	printk(KERN_ALERT "Oops, got 8254 interrupt.\n");
	ArcRead(0, &c, 1, &cnt);
	ArcEnterInteractiveMode();
	irq_exit();
}

void indy_r4k_timer_interrupt(struct pt_regs *regs)
{
	int irq = SGI_TIMER_IRQ;

	irq_enter();
	kstat_this_cpu.irqs[irq]++;
	timer_interrupt(irq, NULL, regs);
	irq_exit();
}

static void indy_timer_setup(struct irqaction *irq)
{
	/* over-write the handler, we use our own way */
	irq->handler = no_action;

	/* setup irqaction */
	setup_irq(SGI_TIMER_IRQ, irq);
}

void __init ip22_time_init(void)
{
	/* setup hookup functions */
	rtc_mips_get_time = indy_rtc_get_time;
	rtc_mips_set_time = indy_rtc_set_time;

	board_time_init = indy_time_init;
	board_timer_setup = indy_timer_setup;
}