summaryrefslogtreecommitdiffstats
path: root/drivers/clocksource/sh_tmu.c
blob: 21bd77aa6a34c8ac22a742306b5038f24963a130 (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
/*
 * SuperH Timer Support - TMU
 *
 *  Copyright (C) 2009 Magnus Damm
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/irq.h>
#include <linux/err.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/sh_tmu.h>

struct sh_tmu_priv {
	void __iomem *mapbase;
	struct clk *clk;
	struct irqaction irqaction;
	struct platform_device *pdev;
	unsigned long rate;
	unsigned long periodic;
	struct clock_event_device ced;
	struct clocksource cs;
};

static DEFINE_SPINLOCK(sh_tmu_lock);

#define TSTR -1 /* shared register */
#define TCOR  0 /* channel register */
#define TCNT 1 /* channel register */
#define TCR 2 /* channel register */

static inline unsigned long sh_tmu_read(struct sh_tmu_priv *p, int reg_nr)
{
	struct sh_tmu_config *cfg = p->pdev->dev.platform_data;
	void __iomem *base = p->mapbase;
	unsigned long offs;

	if (reg_nr == TSTR)
		return ioread8(base - cfg->channel_offset);

	offs = reg_nr << 2;

	if (reg_nr == TCR)
		return ioread16(base + offs);
	else
		return ioread32(base + offs);
}

static inline void sh_tmu_write(struct sh_tmu_priv *p, int reg_nr,
				unsigned long value)
{
	struct sh_tmu_config *cfg = p->pdev->dev.platform_data;
	void __iomem *base = p->mapbase;
	unsigned long offs;

	if (reg_nr == TSTR) {
		iowrite8(value, base - cfg->channel_offset);
		return;
	}

	offs = reg_nr << 2;

	if (reg_nr == TCR)
		iowrite16(value, base + offs);
	else
		iowrite32(value, base + offs);
}

static void sh_tmu_start_stop_ch(struct sh_tmu_priv *p, int start)
{
	struct sh_tmu_config *cfg = p->pdev->dev.platform_data;
	unsigned long flags, value;

	/* start stop register shared by multiple timer channels */
	spin_lock_irqsave(&sh_tmu_lock, flags);
	value = sh_tmu_read(p, TSTR);

	if (start)
		value |= 1 << cfg->timer_bit;
	else
		value &= ~(1 << cfg->timer_bit);

	sh_tmu_write(p, TSTR, value);
	spin_unlock_irqrestore(&sh_tmu_lock, flags);
}

static int sh_tmu_enable(struct sh_tmu_priv *p)
{
	struct sh_tmu_config *cfg = p->pdev->dev.platform_data;
	int ret;

	/* enable clock */
	ret = clk_enable(p->clk);
	if (ret) {
		pr_err("sh_tmu: cannot enable clock \"%s\"\n", cfg->clk);
		return ret;
	}

	/* make sure channel is disabled */
	sh_tmu_start_stop_ch(p, 0);

	/* maximum timeout */
	sh_tmu_write(p, TCOR, 0xffffffff);
	sh_tmu_write(p, TCNT, 0xffffffff);

	/* configure channel to parent clock / 4, irq off */
	p->rate = clk_get_rate(p->clk) / 4;
	sh_tmu_write(p, TCR, 0x0000);

	/* enable channel */
	sh_tmu_start_stop_ch(p, 1);

	return 0;
}

static void sh_tmu_disable(struct sh_tmu_priv *p)
{
	/* disable channel */
	sh_tmu_start_stop_ch(p, 0);

	/* stop clock */
	clk_disable(p->clk);
}

static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
			    int periodic)
{
	/* stop timer */
	sh_tmu_start_stop_ch(p, 0);

	/* acknowledge interrupt */
	sh_tmu_read(p, TCR);

	/* enable interrupt */
	sh_tmu_write(p, TCR, 0x0020);

	/* reload delta value in case of periodic timer */
	if (periodic)
		sh_tmu_write(p, TCOR, delta);
	else
		sh_tmu_write(p, TCOR, 0);

	sh_tmu_write(p, TCNT, delta);

	/* start timer */
	sh_tmu_start_stop_ch(p, 1);
}

static irqreturn_t sh_tmu_interrupt(int irq, void *dev_id)
{
	struct sh_tmu_priv *p = dev_id;

	/* disable or acknowledge interrupt */
	if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT)
		sh_tmu_write(p, TCR, 0x0000);
	else
		sh_tmu_write(p, TCR, 0x0020);

	/* notify clockevent layer */
	p->ced.event_handler(&p->ced);
	return IRQ_HANDLED;
}

static struct sh_tmu_priv *cs_to_sh_tmu(struct clocksource *cs)
{
	return container_of(cs, struct sh_tmu_priv, cs);
}

static cycle_t sh_tmu_clocksource_read(struct clocksource *cs)
{
	struct sh_tmu_priv *p = cs_to_sh_tmu(cs);

	return sh_tmu_read(p, TCNT) ^ 0xffffffff;
}

static int sh_tmu_clocksource_enable(struct clocksource *cs)
{
	struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
	int ret;

	ret = sh_tmu_enable(p);
	if (ret)
		return ret;

	/* TODO: calculate good shift from rate and counter bit width */
	cs->shift = 10;
	cs->mult = clocksource_hz2mult(p->rate, cs->shift);
	return 0;
}

static void sh_tmu_clocksource_disable(struct clocksource *cs)
{
	sh_tmu_disable(cs_to_sh_tmu(cs));
}

static int sh_tmu_register_clocksource(struct sh_tmu_priv *p,
				       char *name, unsigned long rating)
{
	struct clocksource *cs = &p->cs;

	cs->name = name;
	cs->rating = rating;
	cs->read = sh_tmu_clocksource_read;
	cs->enable = sh_tmu_clocksource_enable;
	cs->disable = sh_tmu_clocksource_disable;
	cs->mask = CLOCKSOURCE_MASK(32);
	cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
	pr_info("sh_tmu: %s used as clock source\n", cs->name);
	clocksource_register(cs);
	return 0;
}

static struct sh_tmu_priv *ced_to_sh_tmu(struct clock_event_device *ced)
{
	return container_of(ced, struct sh_tmu_priv, ced);
}

static void sh_tmu_clock_event_start(struct sh_tmu_priv *p, int periodic)
{
	struct clock_event_device *ced = &p->ced;

	sh_tmu_enable(p);

	/* TODO: calculate good shift from rate and counter bit width */

	ced->shift = 32;
	ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
	ced->max_delta_ns = clockevent_delta2ns(0xffffffff, ced);
	ced->min_delta_ns = 5000;

	if (periodic) {
		p->periodic = (p->rate + HZ/2) / HZ;
		sh_tmu_set_next(p, p->periodic, 1);
	}
}

static void sh_tmu_clock_event_mode(enum clock_event_mode mode,
				    struct clock_event_device *ced)
{
	struct sh_tmu_priv *p = ced_to_sh_tmu(ced);
	int disabled = 0;

	/* deal with old setting first */
	switch (ced->mode) {
	case CLOCK_EVT_MODE_PERIODIC:
	case CLOCK_EVT_MODE_ONESHOT:
		sh_tmu_disable(p);
		disabled = 1;
		break;
	default:
		break;
	}

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		pr_info("sh_tmu: %s used for periodic clock events\n",
			ced->name);
		sh_tmu_clock_event_start(p, 1);
		break;
	case CLOCK_EVT_MODE_ONESHOT:
		pr_info("sh_tmu: %s used for oneshot clock events\n",
			ced->name);
		sh_tmu_clock_event_start(p, 0);
		break;
	case CLOCK_EVT_MODE_UNUSED:
		if (!disabled)
			sh_tmu_disable(p);
		break;
	case CLOCK_EVT_MODE_SHUTDOWN:
	default:
		break;
	}
}

static int sh_tmu_clock_event_next(unsigned long delta,
				   struct clock_event_device *ced)
{
	struct sh_tmu_priv *p = ced_to_sh_tmu(ced);

	BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);

	/* program new delta value */
	sh_tmu_set_next(p, delta, 0);
	return 0;
}

static void sh_tmu_register_clockevent(struct sh_tmu_priv *p,
				       char *name, unsigned long rating)
{
	struct clock_event_device *ced = &p->ced;
	int ret;

	memset(ced, 0, sizeof(*ced));

	ced->name = name;
	ced->features = CLOCK_EVT_FEAT_PERIODIC;
	ced->features |= CLOCK_EVT_FEAT_ONESHOT;
	ced->rating = rating;
	ced->cpumask = cpumask_of(0);
	ced->set_next_event = sh_tmu_clock_event_next;
	ced->set_mode = sh_tmu_clock_event_mode;

	ret = setup_irq(p->irqaction.irq, &p->irqaction);
	if (ret) {
		pr_err("sh_tmu: failed to request irq %d\n",
		       p->irqaction.irq);
		return;
	}

	pr_info("sh_tmu: %s used for clock events\n", ced->name);
	clockevents_register_device(ced);
}

static int sh_tmu_register(struct sh_tmu_priv *p, char *name,
		    unsigned long clockevent_rating,
		    unsigned long clocksource_rating)
{
	if (clockevent_rating)
		sh_tmu_register_clockevent(p, name, clockevent_rating);
	else if (clocksource_rating)
		sh_tmu_register_clocksource(p, name, clocksource_rating);

	return 0;
}

static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev)
{
	struct sh_tmu_config *cfg = pdev->dev.platform_data;
	struct resource *res;
	int irq, ret;
	ret = -ENXIO;

	memset(p, 0, sizeof(*p));
	p->pdev = pdev;

	if (!cfg) {
		dev_err(&p->pdev->dev, "missing platform data\n");
		goto err0;
	}

	platform_set_drvdata(pdev, p);

	res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&p->pdev->dev, "failed to get I/O memory\n");
		goto err0;
	}

	irq = platform_get_irq(p->pdev, 0);
	if (irq < 0) {
		dev_err(&p->pdev->dev, "failed to get irq\n");
		goto err0;
	}

	/* map memory, let mapbase point to our channel */
	p->mapbase = ioremap_nocache(res->start, resource_size(res));
	if (p->mapbase == NULL) {
		pr_err("sh_tmu: failed to remap I/O memory\n");
		goto err0;
	}

	/* setup data for setup_irq() (too early for request_irq()) */
	p->irqaction.name = cfg->name;
	p->irqaction.handler = sh_tmu_interrupt;
	p->irqaction.dev_id = p;
	p->irqaction.irq = irq;
	p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL;
	p->irqaction.mask = CPU_MASK_NONE;

	/* get hold of clock */
	p->clk = clk_get(&p->pdev->dev, cfg->clk);
	if (IS_ERR(p->clk)) {
		pr_err("sh_tmu: cannot get clock \"%s\"\n", cfg->clk);
		ret = PTR_ERR(p->clk);
		goto err1;
	}

	return sh_tmu_register(p, cfg->name,
			       cfg->clockevent_rating,
			       cfg->clocksource_rating);
 err1:
	iounmap(p->mapbase);
 err0:
	return ret;
}

static int __devinit sh_tmu_probe(struct platform_device *pdev)
{
	struct sh_tmu_priv *p = platform_get_drvdata(pdev);
	struct sh_tmu_config *cfg = pdev->dev.platform_data;
	int ret;

	if (p) {
		pr_info("sh_tmu: %s kept as earlytimer\n", cfg->name);
		return 0;
	}

	p = kmalloc(sizeof(*p), GFP_KERNEL);
	if (p == NULL) {
		dev_err(&pdev->dev, "failed to allocate driver data\n");
		return -ENOMEM;
	}

	ret = sh_tmu_setup(p, pdev);
	if (ret) {
		kfree(p);
		platform_set_drvdata(pdev, NULL);
	}
	return ret;
}

static int __devexit sh_tmu_remove(struct platform_device *pdev)
{
	return -EBUSY; /* cannot unregister clockevent and clocksource */
}

static struct platform_driver sh_tmu_device_driver = {
	.probe		= sh_tmu_probe,
	.remove		= __devexit_p(sh_tmu_remove),
	.driver		= {
		.name	= "sh_tmu",
	}
};

static int __init sh_tmu_init(void)
{
	return platform_driver_register(&sh_tmu_device_driver);
}

static void __exit sh_tmu_exit(void)
{
	platform_driver_unregister(&sh_tmu_device_driver);
}

early_platform_init("earlytimer", &sh_tmu_device_driver);
module_init(sh_tmu_init);
module_exit(sh_tmu_exit);

MODULE_AUTHOR("Magnus Damm");
MODULE_DESCRIPTION("SuperH TMU Timer Driver");
MODULE_LICENSE("GPL v2");
OpenPOWER on IntegriCloud