aboutsummaryrefslogtreecommitdiff
path: root/arch/ppc/platforms/pmac_time.c
blob: efb819f9490df1a7f90063647475fa35a010c4fe (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
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
/*
 * Support for periodic interrupts (100 per second) and for getting
 * the current time from the RTC on Power Macintoshes.
 *
 * We use the decrementer register for our periodic interrupts.
 *
 * Paul Mackerras	August 1996.
 * Copyright (C) 1996 Paul Mackerras.
 */
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/adb.h>
#include <linux/cuda.h>
#include <linux/pmu.h>
#include <linux/hardirq.h>

#include <asm/sections.h>
#include <asm/prom.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/machdep.h>
#include <asm/time.h>
#include <asm/nvram.h>

/* Apparently the RTC stores seconds since 1 Jan 1904 */
#define RTC_OFFSET	2082844800

/*
 * Calibrate the decrementer frequency with the VIA timer 1.
 */
#define VIA_TIMER_FREQ_6	4700000	/* time 1 frequency * 6 */

/* VIA registers */
#define RS		0x200		/* skip between registers */
#define T1CL		(4*RS)		/* Timer 1 ctr/latch (low 8 bits) */
#define T1CH		(5*RS)		/* Timer 1 counter (high 8 bits) */
#define T1LL		(6*RS)		/* Timer 1 latch (low 8 bits) */
#define T1LH		(7*RS)		/* Timer 1 latch (high 8 bits) */
#define ACR		(11*RS)		/* Auxiliary control register */
#define IFR		(13*RS)		/* Interrupt flag register */

/* Bits in ACR */
#define T1MODE		0xc0		/* Timer 1 mode */
#define T1MODE_CONT	0x40		/*  continuous interrupts */

/* Bits in IFR and IER */
#define T1_INT		0x40		/* Timer 1 interrupt */

extern struct timezone sys_tz;

long __init
pmac_time_init(void)
{
#ifdef CONFIG_NVRAM
	s32 delta = 0;
	int dst;
	
	delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16;
	delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8;
	delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb);
	if (delta & 0x00800000UL)
		delta |= 0xFF000000UL;
	dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0);
	printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60,
		dst ? "on" : "off");
	return delta;
#else
	return 0;
#endif
}

unsigned long __pmac
pmac_get_rtc_time(void)
{
#if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
	struct adb_request req;
	unsigned long now;
#endif

	/* Get the time from the RTC */
	switch (sys_ctrler) {
#ifdef CONFIG_ADB_CUDA
	case SYS_CTRLER_CUDA:
		if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
			return 0;
		while (!req.complete)
			cuda_poll();
		if (req.reply_len != 7)
			printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n",
			       req.reply_len);
		now = (req.reply[3] << 24) + (req.reply[4] << 16)
			+ (req.reply[5] << 8) + req.reply[6];
		return now - RTC_OFFSET;
#endif /* CONFIG_ADB_CUDA */
#ifdef CONFIG_ADB_PMU
	case SYS_CTRLER_PMU:
		if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0)
			return 0;
		while (!req.complete)
			pmu_poll();
		if (req.reply_len != 4)
			printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n",
			       req.reply_len);
		now = (req.reply[0] << 24) + (req.reply[1] << 16)
			+ (req.reply[2] << 8) + req.reply[3];
		return now - RTC_OFFSET;
#endif /* CONFIG_ADB_PMU */
	default: ;
	}
	return 0;
}

int __pmac
pmac_set_rtc_time(unsigned long nowtime)
{
#if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
	struct adb_request req;
#endif

	nowtime += RTC_OFFSET;

	switch (sys_ctrler) {
#ifdef CONFIG_ADB_CUDA
	case SYS_CTRLER_CUDA:
		if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
				 nowtime >> 24, nowtime >> 16, nowtime >> 8, nowtime) < 0)
			return 0;
		while (!req.complete)
			cuda_poll();
		if ((req.reply_len != 3) && (req.reply_len != 7))
			printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n",
			       req.reply_len);
		return 1;
#endif /* CONFIG_ADB_CUDA */
#ifdef CONFIG_ADB_PMU
	case SYS_CTRLER_PMU:
		if (pmu_request(&req, NULL, 5, PMU_SET_RTC,
				nowtime >> 24, nowtime >> 16, nowtime >> 8, nowtime) < 0)
			return 0;
		while (!req.complete)
			pmu_poll();
		if (req.reply_len != 0)
			printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n",
			       req.reply_len);
		return 1;
#endif /* CONFIG_ADB_PMU */
	default:
		return 0;
	}
}

/*
 * Calibrate the decrementer register using VIA timer 1.
 * This is used both on powermacs and CHRP machines.
 */
int __init
via_calibrate_decr(void)
{
	struct device_node *vias;
	volatile unsigned char __iomem *via;
	int count = VIA_TIMER_FREQ_6 / 100;
	unsigned int dstart, dend;

	vias = find_devices("via-cuda");
	if (vias == 0)
		vias = find_devices("via-pmu");
	if (vias == 0)
		vias = find_devices("via");
	if (vias == 0 || vias->n_addrs == 0)
		return 0;
	via = ioremap(vias->addrs[0].address, vias->addrs[0].size);

	/* set timer 1 for continuous interrupts */
	out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
	/* set the counter to a small value */
	out_8(&via[T1CH], 2);
	/* set the latch to `count' */
	out_8(&via[T1LL], count);
	out_8(&via[T1LH], count >> 8);
	/* wait until it hits 0 */
	while ((in_8(&via[IFR]) & T1_INT) == 0)
		;
	dstart = get_dec();
	/* clear the interrupt & wait until it hits 0 again */
	in_8(&via[T1CL]);
	while ((in_8(&via[IFR]) & T1_INT) == 0)
		;
	dend = get_dec();

	tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100);
	tb_to_us = mulhwu_scale_factor(dstart - dend, 60000);

	printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %u (%u ticks)\n",
	       tb_ticks_per_jiffy, dstart - dend);

	iounmap(via);
	
	return 1;
}

#ifdef CONFIG_PM
/*
 * Reset the time after a sleep.
 */
static int __pmac
time_sleep_notify(struct pmu_sleep_notifier *self, int when)
{
	static unsigned long time_diff;
	unsigned long flags;
	unsigned long seq;

	switch (when) {
	case PBOOK_SLEEP_NOW:
		do {
			seq = read_seqbegin_irqsave(&xtime_lock, flags);
			time_diff = xtime.tv_sec - pmac_get_rtc_time();
		} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
		break;
	case PBOOK_WAKE:
		write_seqlock_irqsave(&xtime_lock, flags);
		xtime.tv_sec = pmac_get_rtc_time() + time_diff;
		xtime.tv_nsec = 0;
		last_rtc_update = xtime.tv_sec;
		write_sequnlock_irqrestore(&xtime_lock, flags);
		break;
	}
	return PBOOK_SLEEP_OK;
}

static struct pmu_sleep_notifier time_sleep_notifier __pmacdata = {
	time_sleep_notify, SLEEP_LEVEL_MISC,
};
#endif /* CONFIG_PM */

/*
 * Query the OF and get the decr frequency.
 * This was taken from the pmac time_init() when merging the prep/pmac
 * time functions.
 */
void __init
pmac_calibrate_decr(void)
{
	struct device_node *cpu;
	unsigned int freq, *fp;

#ifdef CONFIG_PM
	pmu_register_sleep_notifier(&time_sleep_notifier);
#endif /* CONFIG_PM */

	/* We assume MacRISC2 machines have correct device-tree
	 * calibration. That's better since the VIA itself seems
	 * to be slightly off. --BenH
	 */
	if (!machine_is_compatible("MacRISC2") &&
	    !machine_is_compatible("MacRISC3") &&
	    !machine_is_compatible("MacRISC4"))
		if (via_calibrate_decr())
			return;

	/* Special case: QuickSilver G4s seem to have a badly calibrated
	 * timebase-frequency in OF, VIA is much better on these. We should
	 * probably implement calibration based on the KL timer on these
	 * machines anyway... -BenH
	 */
	if (machine_is_compatible("PowerMac3,5"))
		if (via_calibrate_decr())
			return;
	/*
	 * The cpu node should have a timebase-frequency property
	 * to tell us the rate at which the decrementer counts.
	 */
	cpu = find_type_devices("cpu");
	if (cpu == 0)
		panic("can't find cpu node in time_init");
	fp = (unsigned int *) get_property(cpu, "timebase-frequency", NULL);
	if (fp == 0)
		panic("can't get cpu timebase frequency");
	freq = *fp;
	printk("time_init: decrementer frequency = %u.%.6u MHz\n",
	       freq/1000000, freq%1000000);
	tb_ticks_per_jiffy = freq / HZ;
	tb_to_us = mulhwu_scale_factor(freq, 1000000);
}