summaryrefslogtreecommitdiff
path: root/drivers/clocksource/h8300_timer16.c
blob: 82941c1e9e33f0d098ae4b0b7273fa263c3b9ce0 (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
/*
 *  H8/300 16bit Timer driver
 *
 *  Copyright 2015 Yoshinori Sato <ysato@users.sourcefoge.jp>
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/clocksource.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of.h>

#include <asm/segment.h>
#include <asm/irq.h>

#define TSTR	0
#define TSNC	1
#define TMDR	2
#define TOLR	3
#define TISRA	4
#define TISRB	5
#define TISRC	6

#define TCR	0
#define TIOR	1
#define TCNT	2
#define GRA	4
#define GRB	6

#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 timer16_priv {
	struct platform_device *pdev;
	struct clocksource cs;
	struct irqaction irqaction;
	unsigned long total_cycles;
	unsigned long mapbase;
	unsigned long mapcommon;
	unsigned long flags;
	unsigned short gra;
	unsigned short cs_enabled;
	unsigned char enb;
	unsigned char imfa;
	unsigned char imiea;
	unsigned char ovf;
	raw_spinlock_t lock;
	struct clk *clk;
};

static unsigned long timer16_get_counter(struct timer16_priv *p)
{
	unsigned long v1, v2, v3;
	int o1, o2;

	o1 = ctrl_inb(p->mapcommon + TISRC) & p->ovf;

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

	v2 |= 0x10000;
	return v2;
}


static irqreturn_t timer16_interrupt(int irq, void *dev_id)
{
	struct timer16_priv *p = (struct timer16_priv *)dev_id;

	ctrl_outb(ctrl_inb(p->mapcommon + TISRA) & ~p->imfa,
		  p->mapcommon + TISRA);
	p->total_cycles += 0x10000;

	return IRQ_HANDLED;
}

static inline struct timer16_priv *cs_to_priv(struct clocksource *cs)
{
	return container_of(cs, struct timer16_priv, cs);
}

static cycle_t timer16_clocksource_read(struct clocksource *cs)
{
	struct timer16_priv *p = cs_to_priv(cs);
	unsigned long flags, raw;
	unsigned long value;

	raw_spin_lock_irqsave(&p->lock, flags);
	value = p->total_cycles;
	raw = timer16_get_counter(p);
	raw_spin_unlock_irqrestore(&p->lock, flags);

	return value + raw;
}

static int timer16_enable(struct clocksource *cs)
{
	struct timer16_priv *p = cs_to_priv(cs);

	WARN_ON(p->cs_enabled);

	p->total_cycles = 0;
	ctrl_outw(0x0000, p->mapbase + TCNT);
	ctrl_outb(0x83, p->mapbase + TCR);
	ctrl_outb(ctrl_inb(p->mapcommon + TSTR) | p->enb,
		  p->mapcommon + TSTR);

	p->cs_enabled = true;
	return 0;
}

static void timer16_disable(struct clocksource *cs)
{
	struct timer16_priv *p = cs_to_priv(cs);

	WARN_ON(!p->cs_enabled);

	ctrl_outb(ctrl_inb(p->mapcommon + TSTR) & ~p->enb,
		  p->mapcommon + TSTR);

	p->cs_enabled = false;
}

#define REG_CH   0
#define REG_COMM 1

static int timer16_setup(struct timer16_priv *p, struct platform_device *pdev)
{
	struct resource *res[2];
	int ret, irq;
	unsigned int ch;

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

	res[REG_CH] = platform_get_resource(p->pdev,
					    IORESOURCE_MEM, REG_CH);
	res[REG_COMM] = platform_get_resource(p->pdev,
					      IORESOURCE_MEM, REG_COMM);
	if (!res[REG_CH] || !res[REG_COMM]) {
		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 irq;
	}

	p->clk = clk_get(&p->pdev->dev, "fck");
	if (IS_ERR(p->clk)) {
		dev_err(&p->pdev->dev, "can't get clk\n");
		return PTR_ERR(p->clk);
	}
	of_property_read_u32(p->pdev->dev.of_node, "renesas,channel", &ch);

	p->pdev = pdev;
	p->mapbase = res[REG_CH]->start;
	p->mapcommon = res[REG_COMM]->start;
	p->enb = 1 << ch;
	p->imfa = 1 << ch;
	p->imiea = 1 << (4 + ch);
	p->cs.name = pdev->name;
	p->cs.rating = 200;
	p->cs.read = timer16_clocksource_read;
	p->cs.enable = timer16_enable;
	p->cs.disable = timer16_disable;
	p->cs.mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
	p->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;

	ret = request_irq(irq, timer16_interrupt,
			  IRQF_TIMER, pdev->name, p);
	if (ret < 0) {
		dev_err(&p->pdev->dev, "failed to request irq %d\n", irq);
		return ret;
	}

	clocksource_register_hz(&p->cs, clk_get_rate(p->clk) / 8);

	return 0;
}

static int timer16_probe(struct platform_device *pdev)
{
	struct timer16_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 timer16_setup(p, pdev);
}

static int timer16_remove(struct platform_device *pdev)
{
	return -EBUSY;
}

static const struct of_device_id timer16_of_table[] = {
	{ .compatible = "renesas,16bit-timer" },
	{ }
};
static struct platform_driver timer16_driver = {
	.probe		= timer16_probe,
	.remove		= timer16_remove,
	.driver		= {
		.name	= "h8300h-16timer",
		.of_match_table = of_match_ptr(timer16_of_table),
	}
};

static int __init timer16_init(void)
{
	return platform_driver_register(&timer16_driver);
}

static void __exit timer16_exit(void)
{
	platform_driver_unregister(&timer16_driver);
}

subsys_initcall(timer16_init);
module_exit(timer16_exit);
MODULE_AUTHOR("Yoshinori Sato");
MODULE_DESCRIPTION("H8/300H 16bit Timer Driver");
MODULE_LICENSE("GPL v2");