summaryrefslogtreecommitdiff
path: root/drivers/watchdog/orion_wdt.c
blob: 788aa158e78c054eef91dabae21de96fa3e20d32 (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
/*
 * drivers/watchdog/orion_wdt.c
 *
 * Watchdog driver for Orion/Kirkwood processors
 *
 * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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/platform_device.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <mach/bridge-regs.h>
#include <plat/orion_wdt.h>

/*
 * Watchdog timer block registers.
 */
#define TIMER_CTRL		0x0000
#define  WDT_EN			0x0010
#define WDT_VAL			0x0024

#define WDT_MAX_CYCLE_COUNT	0xffffffff
#define WDT_IN_USE		0
#define WDT_OK_TO_CLOSE		1

static bool nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = -1;		/* module parameter (seconds) */
static unsigned int wdt_max_duration;	/* (seconds) */
static unsigned int wdt_tclk;
static void __iomem *wdt_reg;
static unsigned long wdt_status;
static DEFINE_SPINLOCK(wdt_lock);

static void orion_wdt_ping(void)
{
	spin_lock(&wdt_lock);

	/* Reload watchdog duration */
	writel(wdt_tclk * heartbeat, wdt_reg + WDT_VAL);

	spin_unlock(&wdt_lock);
}

static void orion_wdt_enable(void)
{
	u32 reg;

	spin_lock(&wdt_lock);

	/* Set watchdog duration */
	writel(wdt_tclk * heartbeat, wdt_reg + WDT_VAL);

	/* Clear watchdog timer interrupt */
	reg = readl(BRIDGE_CAUSE);
	reg &= ~WDT_INT_REQ;
	writel(reg, BRIDGE_CAUSE);

	/* Enable watchdog timer */
	reg = readl(wdt_reg + TIMER_CTRL);
	reg |= WDT_EN;
	writel(reg, wdt_reg + TIMER_CTRL);

	/* Enable reset on watchdog */
	reg = readl(RSTOUTn_MASK);
	reg |= WDT_RESET_OUT_EN;
	writel(reg, RSTOUTn_MASK);

	spin_unlock(&wdt_lock);
}

static void orion_wdt_disable(void)
{
	u32 reg;

	spin_lock(&wdt_lock);

	/* Disable reset on watchdog */
	reg = readl(RSTOUTn_MASK);
	reg &= ~WDT_RESET_OUT_EN;
	writel(reg, RSTOUTn_MASK);

	/* Disable watchdog timer */
	reg = readl(wdt_reg + TIMER_CTRL);
	reg &= ~WDT_EN;
	writel(reg, wdt_reg + TIMER_CTRL);

	spin_unlock(&wdt_lock);
}

static int orion_wdt_get_timeleft(int *time_left)
{
	spin_lock(&wdt_lock);
	*time_left = readl(wdt_reg + WDT_VAL) / wdt_tclk;
	spin_unlock(&wdt_lock);
	return 0;
}

static int orion_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
		return -EBUSY;
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	orion_wdt_enable();
	return nonseekable_open(inode, file);
}

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

			clear_bit(WDT_OK_TO_CLOSE, &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, &wdt_status);
			}
		}
		orion_wdt_ping();
	}
	return len;
}

static int orion_wdt_settimeout(int new_time)
{
	if ((new_time <= 0) || (new_time > wdt_max_duration))
		return -EINVAL;

	/* Set new watchdog time to be used when
	 * orion_wdt_enable() or orion_wdt_ping() is called. */
	heartbeat = new_time;
	return 0;
}

static const struct watchdog_info ident = {
	.options	= WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
			  WDIOF_KEEPALIVEPING,
	.identity	= "Orion Watchdog",
};

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

	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:
		orion_wdt_ping();
		ret = 0;
		break;

	case WDIOC_SETTIMEOUT:
		ret = get_user(time, (int *)arg);
		if (ret)
			break;

		if (orion_wdt_settimeout(time)) {
			ret = -EINVAL;
			break;
		}
		orion_wdt_ping();
		/* Fall through */

	case WDIOC_GETTIMEOUT:
		ret = put_user(heartbeat, (int *)arg);
		break;

	case WDIOC_GETTIMELEFT:
		if (orion_wdt_get_timeleft(&time)) {
			ret = -EINVAL;
			break;
		}
		ret = put_user(time, (int *)arg);
		break;
	}
	return ret;
}

static int orion_wdt_release(struct inode *inode, struct file *file)
{
	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
		orion_wdt_disable();
	else
		pr_crit("Device closed unexpectedly - timer will not stop\n");
	clear_bit(WDT_IN_USE, &wdt_status);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return 0;
}


static const struct file_operations orion_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= orion_wdt_write,
	.unlocked_ioctl	= orion_wdt_ioctl,
	.open		= orion_wdt_open,
	.release	= orion_wdt_release,
};

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

static int __devinit orion_wdt_probe(struct platform_device *pdev)
{
	struct orion_wdt_platform_data *pdata = pdev->dev.platform_data;
	struct resource *res;
	int ret;

	if (pdata) {
		wdt_tclk = pdata->tclk;
	} else {
		pr_err("misses platform data\n");
		return -ENODEV;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	wdt_reg = ioremap(res->start, resource_size(res));

	if (orion_wdt_miscdev.parent)
		return -EBUSY;
	orion_wdt_miscdev.parent = &pdev->dev;

	wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
	if (orion_wdt_settimeout(heartbeat))
		heartbeat = wdt_max_duration;

	ret = misc_register(&orion_wdt_miscdev);
	if (ret)
		return ret;

	pr_info("Initial timeout %d sec%s\n",
		heartbeat, nowayout ? ", nowayout" : "");
	return 0;
}

static int __devexit orion_wdt_remove(struct platform_device *pdev)
{
	int ret;

	if (test_bit(WDT_IN_USE, &wdt_status)) {
		orion_wdt_disable();
		clear_bit(WDT_IN_USE, &wdt_status);
	}

	ret = misc_deregister(&orion_wdt_miscdev);
	if (!ret)
		orion_wdt_miscdev.parent = NULL;

	return ret;
}

static void orion_wdt_shutdown(struct platform_device *pdev)
{
	if (test_bit(WDT_IN_USE, &wdt_status))
		orion_wdt_disable();
}

static struct platform_driver orion_wdt_driver = {
	.probe		= orion_wdt_probe,
	.remove		= __devexit_p(orion_wdt_remove),
	.shutdown	= orion_wdt_shutdown,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= "orion_wdt",
	},
};

module_platform_driver(orion_wdt_driver);

MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
MODULE_DESCRIPTION("Orion Processor Watchdog");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");

module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);