summaryrefslogtreecommitdiffstats
path: root/arch/sh64/kernel/time.c
blob: d1a9b5b078bd4b0c6c864a50dd6949ffc8f6087a (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
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
/*
 * 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.
 *
 * arch/sh64/kernel/time.c
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003 - 2007  Paul Mundt
 * Copyright (C) 2003  Richard Curnow
 *
 *    Original TMU/RTC code taken from sh version.
 *    Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
 *      Some code taken from i386 version.
 *      Copyright (C) 1991, 1992, 1995  Linus Torvalds
 */
#include <linux/errno.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/profile.h>
#include <linux/smp.h>
#include <linux/module.h>
#include <linux/bcd.h>
#include <linux/timex.h>
#include <linux/irq.h>
#include <linux/platform_device.h>
#include <asm/registers.h>	 /* required by inline __asm__ stmt. */
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <asm/hardware.h>

#define TMU_TOCR_INIT	0x00
#define TMU0_TCR_INIT	0x0020
#define TMU_TSTR_INIT	1
#define TMU_TSTR_OFF	0

/* Real Time Clock */
#define	RTC_BLOCK_OFF	0x01040000
#define RTC_BASE	PHYS_PERIPHERAL_BLOCK + RTC_BLOCK_OFF
#define RTC_RCR1_CIE	0x10	/* Carry Interrupt Enable */
#define RTC_RCR1	(rtc_base + 0x38)

/* Clock, Power and Reset Controller */
#define	CPRC_BLOCK_OFF	0x01010000
#define CPRC_BASE	PHYS_PERIPHERAL_BLOCK + CPRC_BLOCK_OFF

#define FRQCR		(cprc_base+0x0)
#define WTCSR		(cprc_base+0x0018)
#define STBCR		(cprc_base+0x0030)

/* Time Management Unit */
#define	TMU_BLOCK_OFF	0x01020000
#define TMU_BASE	PHYS_PERIPHERAL_BLOCK + TMU_BLOCK_OFF
#define TMU0_BASE	tmu_base + 0x8 + (0xc * 0x0)
#define TMU1_BASE	tmu_base + 0x8 + (0xc * 0x1)
#define TMU2_BASE	tmu_base + 0x8 + (0xc * 0x2)

#define TMU_TOCR	tmu_base+0x0	/* Byte access */
#define TMU_TSTR	tmu_base+0x4	/* Byte access */

#define TMU0_TCOR	TMU0_BASE+0x0	/* Long access */
#define TMU0_TCNT	TMU0_BASE+0x4	/* Long access */
#define TMU0_TCR	TMU0_BASE+0x8	/* Word access */

#define TICK_SIZE (tick_nsec / 1000)

static unsigned long tmu_base, rtc_base;
unsigned long cprc_base;

/* Variables to allow interpolation of time of day to resolution better than a
 * jiffy. */

/* This is effectively protected by xtime_lock */
static unsigned long ctc_last_interrupt;
static unsigned long long usecs_per_jiffy = 1000000/HZ; /* Approximation */

#define CTC_JIFFY_SCALE_SHIFT 40

/* 2**CTC_JIFFY_SCALE_SHIFT / ctc_ticks_per_jiffy */
static unsigned long long scaled_recip_ctc_ticks_per_jiffy;

/* Estimate number of microseconds that have elapsed since the last timer tick,
   by scaling the delta that has occurred in the CTC register.

   WARNING WARNING WARNING : This algorithm relies on the CTC decrementing at
   the CPU clock rate.  If the CPU sleeps, the CTC stops counting.  Bear this
   in mind if enabling SLEEP_WORKS in process.c.  In that case, this algorithm
   probably needs to use TMU.TCNT0 instead.  This will work even if the CPU is
   sleeping, though will be coarser.

   FIXME : What if usecs_per_tick is moving around too much, e.g. if an adjtime
   is running or if the freq or tick arguments of adjtimex are modified after
   we have calibrated the scaling factor?  This will result in either a jump at
   the end of a tick period, or a wrap backwards at the start of the next one,
   if the application is reading the time of day often enough.  I think we
   ought to do better than this.  For this reason, usecs_per_jiffy is left
   separated out in the calculation below.  This allows some future hook into
   the adjtime-related stuff in kernel/timer.c to remove this hazard.

*/

static unsigned long usecs_since_tick(void)
{
	unsigned long long current_ctc;
	long ctc_ticks_since_interrupt;
	unsigned long long ull_ctc_ticks_since_interrupt;
	unsigned long result;

	unsigned long long mul1_out;
	unsigned long long mul1_out_high;
	unsigned long long mul2_out_low, mul2_out_high;

	/* Read CTC register */
	asm ("getcon cr62, %0" : "=r" (current_ctc));
	/* Note, the CTC counts down on each CPU clock, not up.
	   Note(2), use long type to get correct wraparound arithmetic when
	   the counter crosses zero. */
	ctc_ticks_since_interrupt = (long) ctc_last_interrupt - (long) current_ctc;
	ull_ctc_ticks_since_interrupt = (unsigned long long) ctc_ticks_since_interrupt;

	/* Inline assembly to do 32x32x32->64 multiplier */
	asm volatile ("mulu.l %1, %2, %0" :
	     "=r" (mul1_out) :
	     "r" (ull_ctc_ticks_since_interrupt), "r" (usecs_per_jiffy));

	mul1_out_high = mul1_out >> 32;

	asm volatile ("mulu.l %1, %2, %0" :
	     "=r" (mul2_out_low) :
	     "r" (mul1_out), "r" (scaled_recip_ctc_ticks_per_jiffy));

#if 1
	asm volatile ("mulu.l %1, %2, %0" :
	     "=r" (mul2_out_high) :
	     "r" (mul1_out_high), "r" (scaled_recip_ctc_ticks_per_jiffy));
#endif

	result = (unsigned long) (((mul2_out_high << 32) + mul2_out_low) >> CTC_JIFFY_SCALE_SHIFT);

	return result;
}

void do_gettimeofday(struct timeval *tv)
{
	unsigned long flags;
	unsigned long seq;
	unsigned long usec, sec;

	do {
		seq = read_seqbegin_irqsave(&xtime_lock, flags);
		usec = usecs_since_tick();
		sec = xtime.tv_sec;
		usec += xtime.tv_nsec / 1000;
	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));

	while (usec >= 1000000) {
		usec -= 1000000;
		sec++;
	}

	tv->tv_sec = sec;
	tv->tv_usec = usec;
}

int do_settimeofday(struct timespec *tv)
{
	time_t wtm_sec, sec = tv->tv_sec;
	long wtm_nsec, nsec = tv->tv_nsec;

	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
		return -EINVAL;

	write_seqlock_irq(&xtime_lock);
	/*
	 * This is revolting. We need to set "xtime" correctly. However, the
	 * value in this location is the value at the most recent update of
	 * wall time.  Discover what correction gettimeofday() would have
	 * made, and then undo it!
	 */
	nsec -= 1000 * usecs_since_tick();

	wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);

	set_normalized_timespec(&xtime, sec, nsec);
	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);

	ntp_clear();
	write_sequnlock_irq(&xtime_lock);
	clock_was_set();

	return 0;
}
EXPORT_SYMBOL(do_settimeofday);

/* Dummy RTC ops */
static void null_rtc_get_time(struct timespec *tv)
{
	tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
	tv->tv_nsec = 0;
}

static int null_rtc_set_time(const time_t secs)
{
	return 0;
}

void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;

/* last time the RTC clock got updated */
static long last_rtc_update;

/*
 * timer_interrupt() needs to keep up the real-time clock,
 * as well as call the "do_timer()" routine every clocktick
 */
static inline void do_timer_interrupt(void)
{
	unsigned long long current_ctc;
	asm ("getcon cr62, %0" : "=r" (current_ctc));
	ctc_last_interrupt = (unsigned long) current_ctc;

	do_timer(1);
#ifndef CONFIG_SMP
	update_process_times(user_mode(get_irq_regs()));
#endif
	if (current->pid)
		profile_tick(CPU_PROFILING);

#ifdef CONFIG_HEARTBEAT
	{
		extern void heartbeat(void);

		heartbeat();
	}
#endif

	/*
	 * If we have an externally synchronized Linux clock, then update
	 * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
	 * called as close as possible to 500 ms before the new second starts.
	 */
	if (ntp_synced() &&
	    xtime.tv_sec > last_rtc_update + 660 &&
	    (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
	    (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
		if (rtc_sh_set_time(xtime.tv_sec) == 0)
			last_rtc_update = xtime.tv_sec;
		else
			/* do it again in 60 s */
			last_rtc_update = xtime.tv_sec - 600;
	}
}

/*
 * This is the same as the above, except we _also_ save the current
 * Time Stamp Counter value at the time of the timer interrupt, so that
 * we later on can estimate the time of day more exactly.
 */
static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
	unsigned long timer_status;

	/* Clear UNF bit */
	timer_status = ctrl_inw(TMU0_TCR);
	timer_status &= ~0x100;
	ctrl_outw(timer_status, TMU0_TCR);

	/*
	 * Here we are in the timer irq handler. We just have irqs locally
	 * disabled but we don't know if the timer_bh is running on the other
	 * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
	 * the irq version of write_lock because as just said we have irq
	 * locally disabled. -arca
	 */
	write_lock(&xtime_lock);
	do_timer_interrupt();
	write_unlock(&xtime_lock);

	return IRQ_HANDLED;
}


static __init unsigned int get_cpu_hz(void)
{
	unsigned int count;
	unsigned long __dummy;
	unsigned long ctc_val_init, ctc_val;

	/*
	** Regardless the toolchain, force the compiler to use the
	** arbitrary register r3 as a clock tick counter.
	** NOTE: r3 must be in accordance with sh64_rtc_interrupt()
	*/
	register unsigned long long  __rtc_irq_flag __asm__ ("r3");

	local_irq_enable();
	do {} while (ctrl_inb(rtc_base) != 0);
	ctrl_outb(RTC_RCR1_CIE, RTC_RCR1); /* Enable carry interrupt */

	/*
	 * r3 is arbitrary. CDC does not support "=z".
	 */
	ctc_val_init = 0xffffffff;
	ctc_val = ctc_val_init;

	asm volatile("gettr	tr0, %1\n\t"
		     "putcon	%0, " __CTC "\n\t"
		     "and	%2, r63, %2\n\t"
		     "pta	$+4, tr0\n\t"
		     "beq/l	%2, r63, tr0\n\t"
		     "ptabs	%1, tr0\n\t"
		     "getcon	" __CTC ", %0\n\t"
		: "=r"(ctc_val), "=r" (__dummy), "=r" (__rtc_irq_flag)
		: "0" (0));
	local_irq_disable();
	/*
	 * SH-3:
	 * CPU clock = 4 stages * loop
	 * tst    rm,rm      if id ex
	 * bt/s   1b            if id ex
	 * add    #1,rd            if id ex
         *                            (if) pipe line stole
	 * tst    rm,rm                  if id ex
         * ....
	 *
	 *
	 * SH-4:
	 * CPU clock = 6 stages * loop
	 * I don't know why.
         * ....
	 *
	 * SH-5:
	 * Use CTC register to count.  This approach returns the right value
	 * even if the I-cache is disabled (e.g. whilst debugging.)
	 *
	 */

	count = ctc_val_init - ctc_val; /* CTC counts down */

#if defined (CONFIG_SH_SIMULATOR)
	/*
	 * Let's pretend we are a 5MHz SH-5 to avoid a too
	 * little timer interval. Also to keep delay
	 * calibration within a reasonable time.
	 */
	return 5000000;
#else
	/*
	 * This really is count by the number of clock cycles
         * by the ratio between a complete R64CNT
         * wrap-around (128) and CUI interrupt being raised (64).
	 */
	return count*2;
#endif
}

static irqreturn_t sh64_rtc_interrupt(int irq, void *dev_id)
{
	struct pt_regs *regs = get_irq_regs();

	ctrl_outb(0, RTC_RCR1);	/* Disable Carry Interrupts */
	regs->regs[3] = 1;	/* Using r3 */

	return IRQ_HANDLED;
}

static struct irqaction irq0  = {
	.handler = timer_interrupt,
	.flags = IRQF_DISABLED,
	.mask = CPU_MASK_NONE,
	.name = "timer",
};
static struct irqaction irq1  = {
	.handler = sh64_rtc_interrupt,
	.flags = IRQF_DISABLED,
	.mask = CPU_MASK_NONE,
	.name = "rtc",
};

void __init time_init(void)
{
	unsigned int cpu_clock, master_clock, bus_clock, module_clock;
	unsigned long interval;
	unsigned long frqcr, ifc, pfc;
	static int ifc_table[] = { 2, 4, 6, 8, 10, 12, 16, 24 };
#define bfc_table ifc_table	/* Same */
#define pfc_table ifc_table	/* Same */

	tmu_base = onchip_remap(TMU_BASE, 1024, "TMU");
	if (!tmu_base) {
		panic("Unable to remap TMU\n");
	}

	rtc_base = onchip_remap(RTC_BASE, 1024, "RTC");
	if (!rtc_base) {
		panic("Unable to remap RTC\n");
	}

	cprc_base = onchip_remap(CPRC_BASE, 1024, "CPRC");
	if (!cprc_base) {
		panic("Unable to remap CPRC\n");
	}

	rtc_sh_get_time(&xtime);

	setup_irq(TIMER_IRQ, &irq0);
	setup_irq(RTC_IRQ, &irq1);

	/* Check how fast it is.. */
	cpu_clock = get_cpu_hz();

	/* Note careful order of operations to maintain reasonable precision and avoid overflow. */
	scaled_recip_ctc_ticks_per_jiffy = ((1ULL << CTC_JIFFY_SCALE_SHIFT) / (unsigned long long)(cpu_clock / HZ));

	free_irq(RTC_IRQ, NULL);

	printk("CPU clock: %d.%02dMHz\n",
	       (cpu_clock / 1000000), (cpu_clock % 1000000)/10000);
	{
		unsigned short bfc;
		frqcr = ctrl_inl(FRQCR);
		ifc  = ifc_table[(frqcr>> 6) & 0x0007];
		bfc  = bfc_table[(frqcr>> 3) & 0x0007];
		pfc  = pfc_table[(frqcr>> 12) & 0x0007];
		master_clock = cpu_clock * ifc;
		bus_clock = master_clock/bfc;
	}

	printk("Bus clock: %d.%02dMHz\n",
	       (bus_clock/1000000), (bus_clock % 1000000)/10000);
	module_clock = master_clock/pfc;
	printk("Module clock: %d.%02dMHz\n",
	       (module_clock/1000000), (module_clock % 1000000)/10000);
	interval = (module_clock/(HZ*4));

	printk("Interval = %ld\n", interval);

	current_cpu_data.cpu_clock    = cpu_clock;
	current_cpu_data.master_clock = master_clock;
	current_cpu_data.bus_clock    = bus_clock;
	current_cpu_data.module_clock = module_clock;

	/* Start TMU0 */
	ctrl_outb(TMU_TSTR_OFF, TMU_TSTR);
	ctrl_outb(TMU_TOCR_INIT, TMU_TOCR);
	ctrl_outw(TMU0_TCR_INIT, TMU0_TCR);
	ctrl_outl(interval, TMU0_TCOR);
	ctrl_outl(interval, TMU0_TCNT);
	ctrl_outb(TMU_TSTR_INIT, TMU_TSTR);
}

void enter_deep_standby(void)
{
	/* Disable watchdog timer */
	ctrl_outl(0xa5000000, WTCSR);
	/* Configure deep standby on sleep */
	ctrl_outl(0x03, STBCR);

#ifdef CONFIG_SH_ALPHANUMERIC
	{
		extern void mach_alphanum(int position, unsigned char value);
		extern void mach_alphanum_brightness(int setting);
		char halted[] = "Halted. ";
		int i;
		mach_alphanum_brightness(6); /* dimmest setting above off */
		for (i=0; i<8; i++) {
			mach_alphanum(i, halted[i]);
		}
		asm __volatile__ ("synco");
	}
#endif

	asm __volatile__ ("sleep");
	asm __volatile__ ("synci");
	asm __volatile__ ("nop");
	asm __volatile__ ("nop");
	asm __volatile__ ("nop");
	asm __volatile__ ("nop");
	panic("Unexpected wakeup!\n");
}

static struct resource rtc_resources[] = {
	[0] = {
		/* RTC base, filled in by rtc_init */
		.flags	= IORESOURCE_IO,
	},
	[1] = {
		/* Period IRQ */
		.start	= IRQ_PRI,
		.flags	= IORESOURCE_IRQ,
	},
	[2] = {
		/* Carry IRQ */
		.start	= IRQ_CUI,
		.flags	= IORESOURCE_IRQ,
	},
	[3] = {
		/* Alarm IRQ */
		.start	= IRQ_ATI,
		.flags	= IORESOURCE_IRQ,
	},
};

static struct platform_device rtc_device = {
	.name		= "sh-rtc",
	.id		= -1,
	.num_resources	= ARRAY_SIZE(rtc_resources),
	.resource	= rtc_resources,
};

static int __init rtc_init(void)
{
	rtc_resources[0].start	= rtc_base;
	rtc_resources[0].end	= rtc_resources[0].start + 0x58 - 1;

	return platform_device_register(&rtc_device);
}
device_initcall(rtc_init);
OpenPOWER on IntegriCloud