summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/sysdev/mpic_timer.c
blob: a42a20280035195279f7ddd8d30da604dd99f71e (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
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * MPIC timer driver
 *
 * Copyright 2013 Freescale Semiconductor, Inc.
 * Author: Dongsheng Wang <Dongsheng.Wang@freescale.com>
 *	   Li Yang <leoli@freescale.com>
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/syscore_ops.h>
#include <sysdev/fsl_soc.h>
#include <asm/io.h>

#include <asm/mpic_timer.h>

#define FSL_GLOBAL_TIMER		0x1

/* Clock Ratio
 * Divide by 64 0x00000300
 * Divide by 32 0x00000200
 * Divide by 16 0x00000100
 * Divide by  8 0x00000000 (Hardware default div)
 */
#define MPIC_TIMER_TCR_CLKDIV		0x00000300

#define MPIC_TIMER_TCR_ROVR_OFFSET	24

#define TIMER_STOP			0x80000000
#define GTCCR_TOG			0x80000000
#define TIMERS_PER_GROUP		4
#define MAX_TICKS			(~0U >> 1)
#define MAX_TICKS_CASCADE		(~0U)
#define TIMER_OFFSET(num)		(1 << (TIMERS_PER_GROUP - 1 - num))

struct timer_regs {
	u32	gtccr;
	u32	res0[3];
	u32	gtbcr;
	u32	res1[3];
	u32	gtvpr;
	u32	res2[3];
	u32	gtdr;
	u32	res3[3];
};

struct cascade_priv {
	u32 tcr_value;			/* TCR register: CASC & ROVR value */
	unsigned int cascade_map;	/* cascade map */
	unsigned int timer_num;		/* cascade control timer */
};

struct timer_group_priv {
	struct timer_regs __iomem	*regs;
	struct mpic_timer		timer[TIMERS_PER_GROUP];
	struct list_head		node;
	unsigned int			timerfreq;
	unsigned int			idle;
	unsigned int			flags;
	spinlock_t			lock;
	void __iomem			*group_tcr;
};

static struct cascade_priv cascade_timer[] = {
	/* cascade timer 0 and 1 */
	{0x1, 0xc, 0x1},
	/* cascade timer 1 and 2 */
	{0x2, 0x6, 0x2},
	/* cascade timer 2 and 3 */
	{0x4, 0x3, 0x3}
};

static LIST_HEAD(timer_group_list);

static void convert_ticks_to_time(struct timer_group_priv *priv,
		const u64 ticks, time64_t *time)
{
	*time = (u64)div_u64(ticks, priv->timerfreq);
}

/* the time set by the user is converted to "ticks" */
static int convert_time_to_ticks(struct timer_group_priv *priv,
		time64_t time, u64 *ticks)
{
	u64 max_value;		/* prevent u64 overflow */

	max_value = div_u64(ULLONG_MAX, priv->timerfreq);

	if (time > max_value)
		return -EINVAL;

	*ticks = (u64)time * (u64)priv->timerfreq;

	return 0;
}

/* detect whether there is a cascade timer available */
static struct mpic_timer *detect_idle_cascade_timer(
					struct timer_group_priv *priv)
{
	struct cascade_priv *casc_priv;
	unsigned int map;
	unsigned int array_size = ARRAY_SIZE(cascade_timer);
	unsigned int num;
	unsigned int i;
	unsigned long flags;

	casc_priv = cascade_timer;
	for (i = 0; i < array_size; i++) {
		spin_lock_irqsave(&priv->lock, flags);
		map = casc_priv->cascade_map & priv->idle;
		if (map == casc_priv->cascade_map) {
			num = casc_priv->timer_num;
			priv->timer[num].cascade_handle = casc_priv;

			/* set timer busy */
			priv->idle &= ~casc_priv->cascade_map;
			spin_unlock_irqrestore(&priv->lock, flags);
			return &priv->timer[num];
		}
		spin_unlock_irqrestore(&priv->lock, flags);
		casc_priv++;
	}

	return NULL;
}

static int set_cascade_timer(struct timer_group_priv *priv, u64 ticks,
		unsigned int num)
{
	struct cascade_priv *casc_priv;
	u32 tcr;
	u32 tmp_ticks;
	u32 rem_ticks;

	/* set group tcr reg for cascade */
	casc_priv = priv->timer[num].cascade_handle;
	if (!casc_priv)
		return -EINVAL;

	tcr = casc_priv->tcr_value |
		(casc_priv->tcr_value << MPIC_TIMER_TCR_ROVR_OFFSET);
	setbits32(priv->group_tcr, tcr);

	tmp_ticks = div_u64_rem(ticks, MAX_TICKS_CASCADE, &rem_ticks);

	out_be32(&priv->regs[num].gtccr, 0);
	out_be32(&priv->regs[num].gtbcr, tmp_ticks | TIMER_STOP);

	out_be32(&priv->regs[num - 1].gtccr, 0);
	out_be32(&priv->regs[num - 1].gtbcr, rem_ticks);

	return 0;
}

static struct mpic_timer *get_cascade_timer(struct timer_group_priv *priv,
					u64 ticks)
{
	struct mpic_timer *allocated_timer;

	/* Two cascade timers: Support the maximum time */
	const u64 max_ticks = (u64)MAX_TICKS * (u64)MAX_TICKS_CASCADE;
	int ret;

	if (ticks > max_ticks)
		return NULL;

	/* detect idle timer */
	allocated_timer = detect_idle_cascade_timer(priv);
	if (!allocated_timer)
		return NULL;

	/* set ticks to timer */
	ret = set_cascade_timer(priv, ticks, allocated_timer->num);
	if (ret < 0)
		return NULL;

	return allocated_timer;
}

static struct mpic_timer *get_timer(time64_t time)
{
	struct timer_group_priv *priv;
	struct mpic_timer *timer;

	u64 ticks;
	unsigned int num;
	unsigned int i;
	unsigned long flags;
	int ret;

	list_for_each_entry(priv, &timer_group_list, node) {
		ret = convert_time_to_ticks(priv, time, &ticks);
		if (ret < 0)
			return NULL;

		if (ticks > MAX_TICKS) {
			if (!(priv->flags & FSL_GLOBAL_TIMER))
				return NULL;

			timer = get_cascade_timer(priv, ticks);
			if (!timer)
				continue;

			return timer;
		}

		for (i = 0; i < TIMERS_PER_GROUP; i++) {
			/* one timer: Reverse allocation */
			num = TIMERS_PER_GROUP - 1 - i;
			spin_lock_irqsave(&priv->lock, flags);
			if (priv->idle & (1 << i)) {
				/* set timer busy */
				priv->idle &= ~(1 << i);
				/* set ticks & stop timer */
				out_be32(&priv->regs[num].gtbcr,
					ticks | TIMER_STOP);
				out_be32(&priv->regs[num].gtccr, 0);
				priv->timer[num].cascade_handle = NULL;
				spin_unlock_irqrestore(&priv->lock, flags);
				return &priv->timer[num];
			}
			spin_unlock_irqrestore(&priv->lock, flags);
		}
	}

	return NULL;
}

/**
 * mpic_start_timer - start hardware timer
 * @handle: the timer to be started.
 *
 * It will do ->fn(->dev) callback from the hardware interrupt at
 * the 'time64_t' point in the future.
 */
void mpic_start_timer(struct mpic_timer *handle)
{
	struct timer_group_priv *priv = container_of(handle,
			struct timer_group_priv, timer[handle->num]);

	clrbits32(&priv->regs[handle->num].gtbcr, TIMER_STOP);
}
EXPORT_SYMBOL(mpic_start_timer);

/**
 * mpic_stop_timer - stop hardware timer
 * @handle: the timer to be stoped
 *
 * The timer periodically generates an interrupt. Unless user stops the timer.
 */
void mpic_stop_timer(struct mpic_timer *handle)
{
	struct timer_group_priv *priv = container_of(handle,
			struct timer_group_priv, timer[handle->num]);
	struct cascade_priv *casc_priv;

	setbits32(&priv->regs[handle->num].gtbcr, TIMER_STOP);

	casc_priv = priv->timer[handle->num].cascade_handle;
	if (casc_priv) {
		out_be32(&priv->regs[handle->num].gtccr, 0);
		out_be32(&priv->regs[handle->num - 1].gtccr, 0);
	} else {
		out_be32(&priv->regs[handle->num].gtccr, 0);
	}
}
EXPORT_SYMBOL(mpic_stop_timer);

/**
 * mpic_get_remain_time - get timer time
 * @handle: the timer to be selected.
 * @time: time for timer
 *
 * Query timer remaining time.
 */
void mpic_get_remain_time(struct mpic_timer *handle, time64_t *time)
{
	struct timer_group_priv *priv = container_of(handle,
			struct timer_group_priv, timer[handle->num]);
	struct cascade_priv *casc_priv;

	u64 ticks;
	u32 tmp_ticks;

	casc_priv = priv->timer[handle->num].cascade_handle;
	if (casc_priv) {
		tmp_ticks = in_be32(&priv->regs[handle->num].gtccr);
		tmp_ticks &= ~GTCCR_TOG;
		ticks = ((u64)tmp_ticks & UINT_MAX) * (u64)MAX_TICKS_CASCADE;
		tmp_ticks = in_be32(&priv->regs[handle->num - 1].gtccr);
		ticks += tmp_ticks;
	} else {
		ticks = in_be32(&priv->regs[handle->num].gtccr);
		ticks &= ~GTCCR_TOG;
	}

	convert_ticks_to_time(priv, ticks, time);
}
EXPORT_SYMBOL(mpic_get_remain_time);

/**
 * mpic_free_timer - free hardware timer
 * @handle: the timer to be removed.
 *
 * Free the timer.
 *
 * Note: can not be used in interrupt context.
 */
void mpic_free_timer(struct mpic_timer *handle)
{
	struct timer_group_priv *priv = container_of(handle,
			struct timer_group_priv, timer[handle->num]);

	struct cascade_priv *casc_priv;
	unsigned long flags;

	mpic_stop_timer(handle);

	casc_priv = priv->timer[handle->num].cascade_handle;

	free_irq(priv->timer[handle->num].irq, priv->timer[handle->num].dev);

	spin_lock_irqsave(&priv->lock, flags);
	if (casc_priv) {
		u32 tcr;
		tcr = casc_priv->tcr_value | (casc_priv->tcr_value <<
					MPIC_TIMER_TCR_ROVR_OFFSET);
		clrbits32(priv->group_tcr, tcr);
		priv->idle |= casc_priv->cascade_map;
		priv->timer[handle->num].cascade_handle = NULL;
	} else {
		priv->idle |= TIMER_OFFSET(handle->num);
	}
	spin_unlock_irqrestore(&priv->lock, flags);
}
EXPORT_SYMBOL(mpic_free_timer);

/**
 * mpic_request_timer - get a hardware timer
 * @fn: interrupt handler function
 * @dev: callback function of the data
 * @time: time for timer
 *
 * This executes the "request_irq", returning NULL
 * else "handle" on success.
 */
struct mpic_timer *mpic_request_timer(irq_handler_t fn, void *dev,
				      time64_t time)
{
	struct mpic_timer *allocated_timer;
	int ret;

	if (list_empty(&timer_group_list))
		return NULL;

	if (time < 0)
		return NULL;

	allocated_timer = get_timer(time);
	if (!allocated_timer)
		return NULL;

	ret = request_irq(allocated_timer->irq, fn,
			IRQF_TRIGGER_LOW, "global-timer", dev);
	if (ret) {
		mpic_free_timer(allocated_timer);
		return NULL;
	}

	allocated_timer->dev = dev;

	return allocated_timer;
}
EXPORT_SYMBOL(mpic_request_timer);

static int timer_group_get_freq(struct device_node *np,
			struct timer_group_priv *priv)
{
	u32 div;

	if (priv->flags & FSL_GLOBAL_TIMER) {
		struct device_node *dn;

		dn = of_find_compatible_node(NULL, NULL, "fsl,mpic");
		if (dn) {
			of_property_read_u32(dn, "clock-frequency",
					&priv->timerfreq);
			of_node_put(dn);
		}
	}

	if (priv->timerfreq <= 0)
		return -EINVAL;

	if (priv->flags & FSL_GLOBAL_TIMER) {
		div = (1 << (MPIC_TIMER_TCR_CLKDIV >> 8)) * 8;
		priv->timerfreq /= div;
	}

	return 0;
}

static int timer_group_get_irq(struct device_node *np,
		struct timer_group_priv *priv)
{
	const u32 all_timer[] = { 0, TIMERS_PER_GROUP };
	const u32 *p;
	u32 offset;
	u32 count;

	unsigned int i;
	unsigned int j;
	unsigned int irq_index = 0;
	unsigned int irq;
	int len;

	p = of_get_property(np, "fsl,available-ranges", &len);
	if (p && len % (2 * sizeof(u32)) != 0) {
		pr_err("%pOF: malformed available-ranges property.\n", np);
		return -EINVAL;
	}

	if (!p) {
		p = all_timer;
		len = sizeof(all_timer);
	}

	len /= 2 * sizeof(u32);

	for (i = 0; i < len; i++) {
		offset = p[i * 2];
		count = p[i * 2 + 1];
		for (j = 0; j < count; j++) {
			irq = irq_of_parse_and_map(np, irq_index);
			if (!irq) {
				pr_err("%pOF: irq parse and map failed.\n", np);
				return -EINVAL;
			}

			/* Set timer idle */
			priv->idle |= TIMER_OFFSET((offset + j));
			priv->timer[offset + j].irq = irq;
			priv->timer[offset + j].num = offset + j;
			irq_index++;
		}
	}

	return 0;
}

static void timer_group_init(struct device_node *np)
{
	struct timer_group_priv *priv;
	unsigned int i = 0;
	int ret;

	priv = kzalloc(sizeof(struct timer_group_priv), GFP_KERNEL);
	if (!priv) {
		pr_err("%pOF: cannot allocate memory for group.\n", np);
		return;
	}

	if (of_device_is_compatible(np, "fsl,mpic-global-timer"))
		priv->flags |= FSL_GLOBAL_TIMER;

	priv->regs = of_iomap(np, i++);
	if (!priv->regs) {
		pr_err("%pOF: cannot ioremap timer register address.\n", np);
		goto out;
	}

	if (priv->flags & FSL_GLOBAL_TIMER) {
		priv->group_tcr = of_iomap(np, i++);
		if (!priv->group_tcr) {
			pr_err("%pOF: cannot ioremap tcr address.\n", np);
			goto out;
		}
	}

	ret = timer_group_get_freq(np, priv);
	if (ret < 0) {
		pr_err("%pOF: cannot get timer frequency.\n", np);
		goto out;
	}

	ret = timer_group_get_irq(np, priv);
	if (ret < 0) {
		pr_err("%pOF: cannot get timer irqs.\n", np);
		goto out;
	}

	spin_lock_init(&priv->lock);

	/* Init FSL timer hardware */
	if (priv->flags & FSL_GLOBAL_TIMER)
		setbits32(priv->group_tcr, MPIC_TIMER_TCR_CLKDIV);

	list_add_tail(&priv->node, &timer_group_list);

	return;

out:
	if (priv->regs)
		iounmap(priv->regs);

	if (priv->group_tcr)
		iounmap(priv->group_tcr);

	kfree(priv);
}

static void mpic_timer_resume(void)
{
	struct timer_group_priv *priv;

	list_for_each_entry(priv, &timer_group_list, node) {
		/* Init FSL timer hardware */
		if (priv->flags & FSL_GLOBAL_TIMER)
			setbits32(priv->group_tcr, MPIC_TIMER_TCR_CLKDIV);
	}
}

static const struct of_device_id mpic_timer_ids[] = {
	{ .compatible = "fsl,mpic-global-timer", },
	{},
};

static struct syscore_ops mpic_timer_syscore_ops = {
	.resume = mpic_timer_resume,
};

static int __init mpic_timer_init(void)
{
	struct device_node *np = NULL;

	for_each_matching_node(np, mpic_timer_ids)
		timer_group_init(np);

	register_syscore_ops(&mpic_timer_syscore_ops);

	if (list_empty(&timer_group_list))
		return -ENODEV;

	return 0;
}
subsys_initcall(mpic_timer_init);