summaryrefslogtreecommitdiff
path: root/drivers/clocksource/h8300_timer8.c
blob: 1c6f8b935a7bfd89093d33e02c62c6c3db942229 (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
/*
 *  linux/arch/h8300/kernel/cpu/timer/timer8.c
 *
 *  Yoshinori Sato <ysato@users.sourcefoge.jp>
 *
 *  8bit Timer driver
 *
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/clockchips.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of.h>

#include <asm/irq.h>

#define _8TCR	0
#define _8TCSR	2
#define TCORA	4
#define TCORB	6
#define _8TCNT	8

#define FLAG_REPROGRAM (1 << 0)
#define FLAG_SKIPEVENT (1 << 1)
#define FLAG_IRQCONTEXT (1 << 2)
#define FLAG_STARTED (1 << 3)

#define ONESHOT  0
#define PERIODIC 1

#define RELATIVE 0
#define ABSOLUTE 1

struct timer8_priv {
	struct platform_device *pdev;
	struct clock_event_device ced;
	struct irqaction irqaction;
	unsigned long mapbase;
	raw_spinlock_t lock;
	unsigned long flags;
	unsigned int rate;
	unsigned int tcora;
	struct clk *pclk;
};

static unsigned long timer8_get_counter(struct timer8_priv *p)
{
	unsigned long v1, v2, v3;
	int o1, o2;

	o1 = ctrl_inb(p->mapbase + _8TCSR) & 0x20;

	/* Make sure the timer value is stable. Stolen from acpi_pm.c */
	do {
		o2 = o1;
		v1 = ctrl_inw(p->mapbase + _8TCNT);
		v2 = ctrl_inw(p->mapbase + _8TCNT);
		v3 = ctrl_inw(p->mapbase + _8TCNT);
		o1 = ctrl_inb(p->mapbase + _8TCSR) & 0x20;
	} while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
			  || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));

	v2 |= o1 << 10;
	return v2;
}

static irqreturn_t timer8_interrupt(int irq, void *dev_id)
{
	struct timer8_priv *p = dev_id;

	ctrl_outb(ctrl_inb(p->mapbase + _8TCSR) & ~0x40,
		  p->mapbase + _8TCSR);
	p->flags |= FLAG_IRQCONTEXT;
	ctrl_outw(p->tcora, p->mapbase + TCORA);
	if (!(p->flags & FLAG_SKIPEVENT)) {
		if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT)
			ctrl_outw(0x0000, p->mapbase + _8TCR);
		p->ced.event_handler(&p->ced);
	}
	p->flags &= ~(FLAG_SKIPEVENT | FLAG_IRQCONTEXT);

	return IRQ_HANDLED;
}

static void timer8_set_next(struct timer8_priv *p, unsigned long delta)
{
	unsigned long flags;
	unsigned long now;

	raw_spin_lock_irqsave(&p->lock, flags);
	if (delta >= 0x10000)
		dev_warn(&p->pdev->dev, "delta out of range\n");
	now = timer8_get_counter(p);
	p->tcora = delta;
	ctrl_outb(ctrl_inb(p->mapbase + _8TCR) | 0x40, p->mapbase + _8TCR);
	if (delta > now)
		ctrl_outw(delta, p->mapbase + TCORA);
	else
		ctrl_outw(now + 1, p->mapbase + TCORA);

	raw_spin_unlock_irqrestore(&p->lock, flags);
}

static int timer8_enable(struct timer8_priv *p)
{
	p->rate = clk_get_rate(p->pclk) / 64;
	ctrl_outw(0xffff, p->mapbase + TCORA);
	ctrl_outw(0x0000, p->mapbase + _8TCNT);
	ctrl_outw(0x0c02, p->mapbase + _8TCR);

	return 0;
}

static int timer8_start(struct timer8_priv *p)
{
	int ret = 0;
	unsigned long flags;

	raw_spin_lock_irqsave(&p->lock, flags);

	if (!(p->flags & FLAG_STARTED))
		ret = timer8_enable(p);

	if (ret)
		goto out;
	p->flags |= FLAG_STARTED;

 out:
	raw_spin_unlock_irqrestore(&p->lock, flags);

	return ret;
}

static void timer8_stop(struct timer8_priv *p)
{
	unsigned long flags;

	raw_spin_lock_irqsave(&p->lock, flags);

	ctrl_outw(0x0000, p->mapbase + _8TCR);

	raw_spin_unlock_irqrestore(&p->lock, flags);
}

static inline struct timer8_priv *ced_to_priv(struct clock_event_device *ced)
{
	return container_of(ced, struct timer8_priv, ced);
}

static void timer8_clock_event_start(struct timer8_priv *p, int periodic)
{
	struct clock_event_device *ced = &p->ced;

	timer8_start(p);

	ced->shift = 32;
	ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
	ced->max_delta_ns = clockevent_delta2ns(0xffff, ced);
	ced->min_delta_ns = clockevent_delta2ns(0x0001, ced);

	timer8_set_next(p, periodic?(p->rate + HZ/2) / HZ:0x10000);
}

static void timer8_clock_event_mode(enum clock_event_mode mode,
				    struct clock_event_device *ced)
{
	struct timer8_priv *p = ced_to_priv(ced);

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		dev_info(&p->pdev->dev, "used for periodic clock events\n");
		timer8_stop(p);
		timer8_clock_event_start(p, PERIODIC);
		break;
	case CLOCK_EVT_MODE_ONESHOT:
		dev_info(&p->pdev->dev, "used for oneshot clock events\n");
		timer8_stop(p);
		timer8_clock_event_start(p, ONESHOT);
		break;
	case CLOCK_EVT_MODE_SHUTDOWN:
	case CLOCK_EVT_MODE_UNUSED:
		timer8_stop(p);
		break;
	default:
		break;
	}
}

static int timer8_clock_event_next(unsigned long delta,
				   struct clock_event_device *ced)
{
	struct timer8_priv *p = ced_to_priv(ced);

	BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
	timer8_set_next(p, delta - 1);

	return 0;
}

static int timer8_setup(struct timer8_priv *p,
			struct platform_device *pdev)
{
	struct resource *res;
	int irq;
	int ret;

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

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

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

	p->mapbase = res->start;

	p->irqaction.name = dev_name(&p->pdev->dev);
	p->irqaction.handler = timer8_interrupt;
	p->irqaction.dev_id = p;
	p->irqaction.flags = IRQF_TIMER;

	p->pclk = clk_get(&p->pdev->dev, "fck");
	if (IS_ERR(p->pclk)) {
		dev_err(&p->pdev->dev, "can't get clk\n");
		return PTR_ERR(p->pclk);
	}

	p->ced.name = pdev->name;
	p->ced.features = CLOCK_EVT_FEAT_PERIODIC |
		CLOCK_EVT_FEAT_ONESHOT;
	p->ced.rating = 200;
	p->ced.cpumask = cpumask_of(0);
	p->ced.set_next_event = timer8_clock_event_next;
	p->ced.set_mode = timer8_clock_event_mode;

	ret = setup_irq(irq, &p->irqaction);
	if (ret < 0) {
		dev_err(&p->pdev->dev,
			"failed to request irq %d\n", irq);
		return ret;
	}
	clockevents_register_device(&p->ced);
	platform_set_drvdata(pdev, p);

	return 0;
}

static int timer8_probe(struct platform_device *pdev)
{
	struct timer8_priv *p = platform_get_drvdata(pdev);

	if (p) {
		dev_info(&pdev->dev, "kept as earlytimer\n");
		return 0;
	}

	p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
	if (!p)
		return -ENOMEM;

	return timer8_setup(p, pdev);
}

static int timer8_remove(struct platform_device *pdev)
{
	return -EBUSY;
}

static const struct of_device_id timer8_of_table[] __maybe_unused = {
	{ .compatible = "renesas,8bit-timer" },
	{ }
};

MODULE_DEVICE_TABLE(of, sh_cmt_of_table);
static struct platform_driver timer8_driver = {
	.probe		= timer8_probe,
	.remove		= timer8_remove,
	.driver		= {
		.name	= "h8300-8timer",
		.of_match_table = of_match_ptr(timer8_of_table),
	}
};

static int __init timer8_init(void)
{
	return platform_driver_register(&timer8_driver);
}

static void __exit timer8_exit(void)
{
	platform_driver_unregister(&timer8_driver);
}

subsys_initcall(timer8_init);
module_exit(timer8_exit);
MODULE_AUTHOR("Yoshinori Sato");
MODULE_DESCRIPTION("H8/300 8bit Timer Driver");
MODULE_LICENSE("GPL v2");