aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/jz4740_wdt.c
blob: 17ef300bccc52ca6e8c78edd1f0cc391f2504147 (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
/*
 *  Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
 *  JZ4740 Watchdog driver
 *
 *  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, or (at your
 *  option) any later version.
 *
 *  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.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/slab.h>

#include <asm/mach-jz4740/timer.h>

#define JZ_REG_WDT_TIMER_DATA     0x0
#define JZ_REG_WDT_COUNTER_ENABLE 0x4
#define JZ_REG_WDT_TIMER_COUNTER  0x8
#define JZ_REG_WDT_TIMER_CONTROL  0xC

#define JZ_WDT_CLOCK_PCLK 0x1
#define JZ_WDT_CLOCK_RTC  0x2
#define JZ_WDT_CLOCK_EXT  0x4

#define WDT_IN_USE        0
#define WDT_OK_TO_CLOSE   1

#define JZ_WDT_CLOCK_DIV_SHIFT   3

#define JZ_WDT_CLOCK_DIV_1    (0 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_4    (1 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_16   (2 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_64   (3 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_256  (4 << JZ_WDT_CLOCK_DIV_SHIFT)
#define JZ_WDT_CLOCK_DIV_1024 (5 << JZ_WDT_CLOCK_DIV_SHIFT)

#define DEFAULT_HEARTBEAT 5
#define MAX_HEARTBEAT     2048

static struct {
	void __iomem *base;
	struct resource	*mem;
	struct clk *rtc_clk;
	unsigned long status;
} jz4740_wdt;

static int heartbeat = DEFAULT_HEARTBEAT;


static void jz4740_wdt_service(void)
{
	writew(0x0, jz4740_wdt.base + JZ_REG_WDT_TIMER_COUNTER);
}

static void jz4740_wdt_set_heartbeat(int new_heartbeat)
{
	unsigned int rtc_clk_rate;
	unsigned int timeout_value;
	unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;

	heartbeat = new_heartbeat;

	rtc_clk_rate = clk_get_rate(jz4740_wdt.rtc_clk);

	timeout_value = rtc_clk_rate * heartbeat;
	while (timeout_value > 0xffff) {
		if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
			/* Requested timeout too high;
			* use highest possible value. */
			timeout_value = 0xffff;
			break;
		}
		timeout_value >>= 2;
		clock_div += (1 << JZ_WDT_CLOCK_DIV_SHIFT);
	}

	writeb(0x0, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
	writew(clock_div, jz4740_wdt.base + JZ_REG_WDT_TIMER_CONTROL);

	writew((u16)timeout_value, jz4740_wdt.base + JZ_REG_WDT_TIMER_DATA);
	writew(0x0, jz4740_wdt.base + JZ_REG_WDT_TIMER_COUNTER);
	writew(clock_div | JZ_WDT_CLOCK_RTC,
		jz4740_wdt.base + JZ_REG_WDT_TIMER_CONTROL);

	writeb(0x1, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
}

static void jz4740_wdt_enable(void)
{
	jz4740_timer_enable_watchdog();
	jz4740_wdt_set_heartbeat(heartbeat);
}

static void jz4740_wdt_disable(void)
{
	jz4740_timer_disable_watchdog();
	writeb(0x0, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
}

static int jz4740_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_IN_USE, &jz4740_wdt.status))
		return -EBUSY;

	jz4740_wdt_enable();

	return nonseekable_open(inode, file);
}

static ssize_t jz4740_wdt_write(struct file *file, const char *data,
		size_t len, loff_t *ppos)
{
	if (len) {
		size_t i;

		clear_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status);
		for (i = 0; i != len; i++) {
			char c;

			if (get_user(c, data + i))
				return -EFAULT;

			if (c == 'V')
				set_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status);
		}
		jz4740_wdt_service();
	}

	return len;
}

static const struct watchdog_info ident = {
	.options = WDIOF_KEEPALIVEPING,
	.identity = "jz4740 Watchdog",
};

static long jz4740_wdt_ioctl(struct file *file,
					unsigned int cmd, unsigned long arg)
{
	int ret = -ENOTTY;
	int heartbeat_seconds;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user((struct watchdog_info *)arg, &ident,
				sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_KEEPALIVE:
		jz4740_wdt_service();
		return 0;

	case WDIOC_SETTIMEOUT:
		if (get_user(heartbeat_seconds, (int __user *)arg))
			return -EFAULT;

		jz4740_wdt_set_heartbeat(heartbeat_seconds);
		return 0;

	case WDIOC_GETTIMEOUT:
		return put_user(heartbeat, (int *)arg);

	default:
		break;
	}

	return ret;
}

static int jz4740_wdt_release(struct inode *inode, struct file *file)
{
	jz4740_wdt_service();

	if (test_and_clear_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status))
		jz4740_wdt_disable();

	clear_bit(WDT_IN_USE, &jz4740_wdt.status);
	return 0;
}

static const struct file_operations jz4740_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = jz4740_wdt_write,
	.unlocked_ioctl = jz4740_wdt_ioctl,
	.open = jz4740_wdt_open,
	.release = jz4740_wdt_release,
};

static struct miscdevice jz4740_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &jz4740_wdt_fops,
};

static int __devinit jz4740_wdt_probe(struct platform_device *pdev)
{
	int ret = 0, size;
	struct resource *res;
	struct device *dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
		dev_err(dev, "failed to get memory region resource\n");
		return -ENXIO;
	}

	size = resource_size(res);
	jz4740_wdt.mem = request_mem_region(res->start, size, pdev->name);
	if (jz4740_wdt.mem == NULL) {
		dev_err(dev, "failed to get memory region\n");
		return -EBUSY;
	}

	jz4740_wdt.base = ioremap_nocache(res->start, size);
	if (jz4740_wdt.base == NULL) {
		dev_err(dev, "failed to map memory region\n");
		ret = -EBUSY;
		goto err_release_region;
	}

	jz4740_wdt.rtc_clk = clk_get(NULL, "rtc");
	if (IS_ERR(jz4740_wdt.rtc_clk)) {
		dev_err(dev, "cannot find RTC clock\n");
		ret = PTR_ERR(jz4740_wdt.rtc_clk);
		goto err_iounmap;
	}

	ret = misc_register(&jz4740_wdt_miscdev);
	if (ret < 0) {
		dev_err(dev, "cannot register misc device\n");
		goto err_disable_clk;
	}

	return 0;

err_disable_clk:
	clk_put(jz4740_wdt.rtc_clk);
err_iounmap:
	iounmap(jz4740_wdt.base);
err_release_region:
	release_mem_region(jz4740_wdt.mem->start,
			resource_size(jz4740_wdt.mem));
	return ret;
}


static int __devexit jz4740_wdt_remove(struct platform_device *pdev)
{
	jz4740_wdt_disable();
	misc_deregister(&jz4740_wdt_miscdev);
	clk_put(jz4740_wdt.rtc_clk);

	iounmap(jz4740_wdt.base);
	jz4740_wdt.base = NULL;

	release_mem_region(jz4740_wdt.mem->start,
				resource_size(jz4740_wdt.mem));
	jz4740_wdt.mem = NULL;

	return 0;
}


static struct platform_driver jz4740_wdt_driver = {
	.probe = jz4740_wdt_probe,
	.remove = __devexit_p(jz4740_wdt_remove),
	.driver = {
		.name = "jz4740-wdt",
		.owner	= THIS_MODULE,
	},
};

module_platform_driver(jz4740_wdt_driver);

MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
MODULE_DESCRIPTION("jz4740 Watchdog Driver");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
		"Watchdog heartbeat period in seconds from 1 to "
		__MODULE_STRING(MAX_HEARTBEAT) ", default "
		__MODULE_STRING(DEFAULT_HEARTBEAT));

MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:jz4740-wdt");