aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-davinci/time.c
blob: 7a55b5c9597124a23345066771b9bb88a5893478 (plain) (blame)
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
/*
 * DaVinci timer subsystem
 *
 * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
 *
 * 2007 (c) MontaVista Software, Inc. This file is licensed under
 * the terms of the GNU General Public License version 2. This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/sched_clock.h>

#include <asm/mach/irq.h>
#include <asm/mach/time.h>

#include <mach/cputype.h>
#include <mach/hardware.h>
#include <mach/time.h>

#include "clock.h"

static struct clock_event_device clockevent_davinci;
static unsigned int davinci_clock_tick_rate;

/*
 * This driver configures the 2 64-bit count-up timers as 4 independent
 * 32-bit count-up timers used as follows:
 */

enum {
	TID_CLOCKEVENT,
	TID_CLOCKSOURCE,
};

/* Timer register offsets */
#define PID12			0x0
#define TIM12			0x10
#define TIM34			0x14
#define PRD12			0x18
#define PRD34			0x1c
#define TCR			0x20
#define TGCR			0x24
#define WDTCR			0x28

/* Offsets of the 8 compare registers */
#define	CMP12_0			0x60
#define	CMP12_1			0x64
#define	CMP12_2			0x68
#define	CMP12_3			0x6c
#define	CMP12_4			0x70
#define	CMP12_5			0x74
#define	CMP12_6			0x78
#define	CMP12_7			0x7c

/* Timer register bitfields */
#define TCR_ENAMODE_DISABLE          0x0
#define TCR_ENAMODE_ONESHOT          0x1
#define TCR_ENAMODE_PERIODIC         0x2
#define TCR_ENAMODE_MASK             0x3

#define TGCR_TIMMODE_SHIFT           2
#define TGCR_TIMMODE_64BIT_GP        0x0
#define TGCR_TIMMODE_32BIT_UNCHAINED 0x1
#define TGCR_TIMMODE_64BIT_WDOG      0x2
#define TGCR_TIMMODE_32BIT_CHAINED   0x3

#define TGCR_TIM12RS_SHIFT           0
#define TGCR_TIM34RS_SHIFT           1
#define TGCR_RESET                   0x0
#define TGCR_UNRESET                 0x1
#define TGCR_RESET_MASK              0x3

#define WDTCR_WDEN_SHIFT             14
#define WDTCR_WDEN_DISABLE           0x0
#define WDTCR_WDEN_ENABLE            0x1
#define WDTCR_WDKEY_SHIFT            16
#define WDTCR_WDKEY_SEQ0             0xa5c6
#define WDTCR_WDKEY_SEQ1             0xda7e

struct timer_s {
	char *name;
	unsigned int id;
	unsigned long period;
	unsigned long opts;
	unsigned long flags;
	void __iomem *base;
	unsigned long tim_off;
	unsigned long prd_off;
	unsigned long enamode_shift;
	struct irqaction irqaction;
};
static struct timer_s timers[];

/* values for 'opts' field of struct timer_s */
#define TIMER_OPTS_DISABLED		0x01
#define TIMER_OPTS_ONESHOT		0x02
#define TIMER_OPTS_PERIODIC		0x04
#define TIMER_OPTS_STATE_MASK		0x07

#define TIMER_OPTS_USE_COMPARE		0x80000000
#define USING_COMPARE(t)		((t)->opts & TIMER_OPTS_USE_COMPARE)

static char *id_to_name[] = {
	[T0_BOT]	= "timer0_0",
	[T0_TOP]	= "timer0_1",
	[T1_BOT]	= "timer1_0",
	[T1_TOP]	= "timer1_1",
};

static int timer32_config(struct timer_s *t)
{
	u32 tcr;
	struct davinci_soc_info *soc_info = &davinci_soc_info;

	if (USING_COMPARE(t)) {
		struct davinci_timer_instance *dtip =
				soc_info->timer_info->timers;
		int event_timer = ID_TO_TIMER(timers[TID_CLOCKEVENT].id);

		/*
		 * Next interrupt should be the current time reg value plus
		 * the new period (using 32-bit unsigned addition/wrapping
		 * to 0 on overflow).  This assumes that the clocksource
		 * is setup to count to 2^32-1 before wrapping around to 0.
		 */
		__raw_writel(__raw_readl(t->base + t->tim_off) + t->period,
			t->base + dtip[event_timer].cmp_off);
	} else {
		tcr = __raw_readl(t->base + TCR);

		/* disable timer */
		tcr &= ~(TCR_ENAMODE_MASK << t->enamode_shift);
		__raw_writel(tcr, t->base + TCR);

		/* reset counter to zero, set new period */
		__raw_writel(0, t->base + t->tim_off);
		__raw_writel(t->period, t->base + t->prd_off);

		/* Set enable mode */
		if (t->opts & TIMER_OPTS_ONESHOT)
			tcr |= TCR_ENAMODE_ONESHOT << t->enamode_shift;
		else if (t->opts & TIMER_OPTS_PERIODIC)
			tcr |= TCR_ENAMODE_PERIODIC << t->enamode_shift;

		__raw_writel(tcr, t->base + TCR);
	}
	return 0;
}

static inline u32 timer32_read(struct timer_s *t)
{
	return __raw_readl(t->base + t->tim_off);
}

static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *evt = &clockevent_davinci;

	evt->event_handler(evt);
	return IRQ_HANDLED;
}

/* called when 32-bit counter wraps */
static irqreturn_t freerun_interrupt(int irq, void *dev_id)
{
	return IRQ_HANDLED;
}

static struct timer_s timers[] = {
	[TID_CLOCKEVENT] = {
		.name      = "clockevent",
		.opts      = TIMER_OPTS_DISABLED,
		.irqaction = {
			.flags   = IRQF_DISABLED | IRQF_TIMER,
			.handler = timer_interrupt,
		}
	},
	[TID_CLOCKSOURCE] = {
		.name       = "free-run counter",
		.period     = ~0,
		.opts       = TIMER_OPTS_PERIODIC,
		.irqaction = {
			.flags   = IRQF_DISABLED | IRQF_TIMER,
			.handler = freerun_interrupt,
		}
	},
};

static void __init timer_init(void)
{
	struct davinci_soc_info *soc_info = &davinci_soc_info;
	struct davinci_timer_instance *dtip = soc_info->timer_info->timers;
	void __iomem *base[2];
	int i;

	/* Global init of each 64-bit timer as a whole */
	for(i=0; i<2; i++) {
		u32 tgcr;

		base[i] = ioremap(dtip[i].base, SZ_4K);
		if (WARN_ON(!base[i]))
			continue;

		/* Disabled, Internal clock source */
		__raw_writel(0, base[i] + TCR);

		/* reset both timers, no pre-scaler for timer34 */
		tgcr = 0;
		__raw_writel(tgcr, base[i] + TGCR);

		/* Set both timers to unchained 32-bit */
		tgcr = TGCR_TIMMODE_32BIT_UNCHAINED << TGCR_TIMMODE_SHIFT;
		__raw_writel(tgcr, base[i] + TGCR);

		/* Unreset timers */
		tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
			(TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
		__raw_writel(tgcr, base[i] + TGCR);

		/* Init both counters to zero */
		__raw_writel(0, base[i] + TIM12);
		__raw_writel(0, base[i] + TIM34);
	}

	/* Init of each timer as a 32-bit timer */
	for (i=0; i< ARRAY_SIZE(timers); i++) {
		struct timer_s *t = &timers[i];
		int timer = ID_TO_TIMER(t->id);
		u32 irq;

		t->base = base[timer];
		if (!t->base)
			continue;

		if (IS_TIMER_BOT(t->id)) {
			t->enamode_shift = 6;
			t->tim_off = TIM12;
			t->prd_off = PRD12;
			irq = dtip[timer].bottom_irq;
		} else {
			t->enamode_shift = 22;
			t->tim_off = TIM34;
			t->prd_off = PRD34;
			irq = dtip[timer].top_irq;
		}

		/* Register interrupt */
		t->irqaction.name = t->name;
		t->irqaction.dev_id = (void *)t;

		if (t->irqaction.handler != NULL) {
			irq = USING_COMPARE(t) ? dtip[i].cmp_irq : irq;
			setup_irq(irq, &t->irqaction);
		}
	}
}

/*
 * clocksource
 */
static cycle_t read_cycles(struct clocksource *cs)
{
	struct timer_s *t = &timers[TID_CLOCKSOURCE];

	return (cycles_t)timer32_read(t);
}

static struct clocksource clocksource_davinci = {
	.rating		= 300,
	.read		= read_cycles,
	.mask		= CLOCKSOURCE_MASK(32),
	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
};

/*
 * Overwrite weak default sched_clock with something more precise
 */
static u32 notrace davinci_read_sched_clock(void)
{
	return timer32_read(&timers[TID_CLOCKSOURCE]);
}

/*
 * clockevent
 */
static int davinci_set_next_event(unsigned long cycles,
				  struct clock_event_device *evt)
{
	struct timer_s *t = &timers[TID_CLOCKEVENT];

	t->period = cycles;
	timer32_config(t);
	return 0;
}

static void davinci_set_mode(enum clock_event_mode mode,
			     struct clock_event_device *evt)
{
	struct timer_s *t = &timers[TID_CLOCKEVENT];

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		t->period = davinci_clock_tick_rate / (HZ);
		t->opts &= ~TIMER_OPTS_STATE_MASK;
		t->opts |= TIMER_OPTS_PERIODIC;
		timer32_config(t);
		break;
	case CLOCK_EVT_MODE_ONESHOT:
		t->opts &= ~TIMER_OPTS_STATE_MASK;
		t->opts |= TIMER_OPTS_ONESHOT;
		break;
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
		t->opts &= ~TIMER_OPTS_STATE_MASK;
		t->opts |= TIMER_OPTS_DISABLED;
		break;
	case CLOCK_EVT_MODE_RESUME:
		break;
	}
}

static struct clock_event_device clockevent_davinci = {
	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
	.shift		= 32,
	.set_next_event	= davinci_set_next_event,
	.set_mode	= davinci_set_mode,
};


void __init davinci_timer_init(void)
{
	struct clk *timer_clk;
	struct davinci_soc_info *soc_info = &davinci_soc_info;
	unsigned int clockevent_id;
	unsigned int clocksource_id;
	static char err[] __initdata = KERN_ERR
		"%s: can't register clocksource!\n";
	int i;

	clockevent_id = soc_info->timer_info->clockevent_id;
	clocksource_id = soc_info->timer_info->clocksource_id;

	timers[TID_CLOCKEVENT].id = clockevent_id;
	timers[TID_CLOCKSOURCE].id = clocksource_id;

	/*
	 * If using same timer for both clock events & clocksource,
	 * a compare register must be used to generate an event interrupt.
	 * This is equivalent to a oneshot timer only (not periodic).
	 */
	if (clockevent_id == clocksource_id) {
		struct davinci_timer_instance *dtip =
				soc_info->timer_info->timers;
		int event_timer = ID_TO_TIMER(clockevent_id);

		/* Only bottom timers can use compare regs */
		if (IS_TIMER_TOP(clockevent_id))
			pr_warning("davinci_timer_init: Invalid use"
				" of system timers.  Results unpredictable.\n");
		else if ((dtip[event_timer].cmp_off == 0)
				|| (dtip[event_timer].cmp_irq == 0))
			pr_warning("davinci_timer_init:  Invalid timer instance"
				" setup.  Results unpredictable.\n");
		else {
			timers[TID_CLOCKEVENT].opts |= TIMER_OPTS_USE_COMPARE;
			clockevent_davinci.features = CLOCK_EVT_FEAT_ONESHOT;
		}
	}

	timer_clk = clk_get(NULL, "timer0");
	BUG_ON(IS_ERR(timer_clk));
	clk_prepare_enable(timer_clk);

	/* init timer hw */
	timer_init();

	davinci_clock_tick_rate = clk_get_rate(timer_clk);

	/* setup clocksource */
	clocksource_davinci.name = id_to_name[clocksource_id];
	if (clocksource_register_hz(&clocksource_davinci,
				    davinci_clock_tick_rate))
		printk(err, clocksource_davinci.name);

	setup_sched_clock(davinci_read_sched_clock, 32,
			  davinci_clock_tick_rate);

	/* setup clockevent */
	clockevent_davinci.name = id_to_name[timers[TID_CLOCKEVENT].id];
	clockevent_davinci.mult = div_sc(davinci_clock_tick_rate, NSEC_PER_SEC,
					 clockevent_davinci.shift);
	clockevent_davinci.max_delta_ns =
		clockevent_delta2ns(0xfffffffe, &clockevent_davinci);
	clockevent_davinci.min_delta_ns = 50000; /* 50 usec */

	clockevent_davinci.cpumask = cpumask_of(0);
	clockevents_register_device(&clockevent_davinci);

	for (i=0; i< ARRAY_SIZE(timers); i++)
		timer32_config(&timers[i]);
}

/* reset board using watchdog timer */
void davinci_watchdog_reset(struct platform_device *pdev)
{
	u32 tgcr, wdtcr;
	void __iomem *base;
	struct clk *wd_clk;

	base = ioremap(pdev->resource[0].start, SZ_4K);
	if (WARN_ON(!base))
		return;

	wd_clk = clk_get(&pdev->dev, NULL);
	if (WARN_ON(IS_ERR(wd_clk)))
		return;
	clk_prepare_enable(wd_clk);

	/* disable, internal clock source */
	__raw_writel(0, base + TCR);

	/* reset timer, set mode to 64-bit watchdog, and unreset */
	tgcr = 0;
	__raw_writel(tgcr, base + TGCR);
	tgcr = TGCR_TIMMODE_64BIT_WDOG << TGCR_TIMMODE_SHIFT;
	tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
		(TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
	__raw_writel(tgcr, base + TGCR);

	/* clear counter and period regs */
	__raw_writel(0, base + TIM12);
	__raw_writel(0, base + TIM34);
	__raw_writel(0, base + PRD12);
	__raw_writel(0, base + PRD34);

	/* put watchdog in pre-active state */
	wdtcr = __raw_readl(base + WDTCR);
	wdtcr = (WDTCR_WDKEY_SEQ0 << WDTCR_WDKEY_SHIFT) |
		(WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
	__raw_writel(wdtcr, base + WDTCR);

	/* put watchdog in active state */
	wdtcr = (WDTCR_WDKEY_SEQ1 << WDTCR_WDKEY_SHIFT) |
		(WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
	__raw_writel(wdtcr, base + WDTCR);

	/* write an invalid value to the WDKEY field to trigger
	 * a watchdog reset */
	wdtcr = 0x00004000;
	__raw_writel(wdtcr, base + WDTCR);
}