summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/ie6xx_wdt.c
blob: 94eef6fec0f358552a370d78dd2753ced222e90e (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
/*
 *      Intel Atom E6xx Watchdog driver
 *
 *      Copyright (C) 2011 Alexander Stein
 *                <alexander.stein@systec-electronic.com>
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of version 2 of the GNU General
 *      Public License as published by the Free Software Foundation.
 *
 *      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.
 *      The full GNU General Public License is included in this
 *      distribution in the file called COPYING.
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/miscdevice.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/spinlock.h>

#define DRIVER_NAME "ie6xx_wdt"

#define PV1	0x00
#define PV2	0x04

#define RR0	0x0c
#define RR1	0x0d
#define WDT_RELOAD	0x01
#define WDT_TOUT	0x02

#define WDTCR	0x10
#define WDT_PRE_SEL	0x04
#define WDT_RESET_SEL	0x08
#define WDT_RESET_EN	0x10
#define WDT_TOUT_EN	0x20

#define DCR	0x14

#define WDTLR	0x18
#define WDT_LOCK	0x01
#define WDT_ENABLE	0x02
#define WDT_TOUT_CNF	0x03

#define MIN_TIME	1
#define MAX_TIME	(10 * 60) /* 10 minutes */
#define DEFAULT_TIME	60

static unsigned int timeout = DEFAULT_TIME;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
		"Default Watchdog timer setting ("
		__MODULE_STRING(DEFAULT_TIME) "s)."
		"The range is from 1 to 600");

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

static u8 resetmode = 0x10;
module_param(resetmode, byte, 0);
MODULE_PARM_DESC(resetmode,
	"Resetmode bits: 0x08 warm reset (cold reset otherwise), "
	"0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)");

static struct {
	unsigned short sch_wdtba;
	struct spinlock unlock_sequence;
#ifdef CONFIG_DEBUG_FS
	struct dentry *debugfs;
#endif
} ie6xx_wdt_data;

/*
 * This is needed to write to preload and reload registers
 * struct ie6xx_wdt_data.unlock_sequence must be used
 * to prevent sequence interrupts
 */
static void ie6xx_wdt_unlock_registers(void)
{
	outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0);
	outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0);
}

static int ie6xx_wdt_ping(struct watchdog_device *wdd)
{
	spin_lock(&ie6xx_wdt_data.unlock_sequence);
	ie6xx_wdt_unlock_registers();
	outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1);
	spin_unlock(&ie6xx_wdt_data.unlock_sequence);
	return 0;
}

static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
{
	u32 preload;
	u64 clock;
	u8 wdtcr;

	/* Watchdog clock is PCI Clock (33MHz) */
	clock = 33000000;
	/* and the preload value is loaded into [34:15] of the down counter */
	preload = (t * clock) >> 15;
	/*
	 * Manual states preload must be one less.
	 * Does not wrap as t is at least 1
	 */
	preload -= 1;

	spin_lock(&ie6xx_wdt_data.unlock_sequence);

	/* Set ResetMode & Enable prescaler for range 10ms to 10 min */
	wdtcr = resetmode & 0x38;
	outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR);

	ie6xx_wdt_unlock_registers();
	outl(0, ie6xx_wdt_data.sch_wdtba + PV1);

	ie6xx_wdt_unlock_registers();
	outl(preload, ie6xx_wdt_data.sch_wdtba + PV2);

	ie6xx_wdt_unlock_registers();
	outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1);

	spin_unlock(&ie6xx_wdt_data.unlock_sequence);

	wdd->timeout = t;
	return 0;
}

static int ie6xx_wdt_start(struct watchdog_device *wdd)
{
	ie6xx_wdt_set_timeout(wdd, wdd->timeout);

	/* Enable the watchdog timer */
	spin_lock(&ie6xx_wdt_data.unlock_sequence);
	outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR);
	spin_unlock(&ie6xx_wdt_data.unlock_sequence);

	return 0;
}

static int ie6xx_wdt_stop(struct watchdog_device *wdd)
{
	if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK)
		return -1;

	/* Disable the watchdog timer */
	spin_lock(&ie6xx_wdt_data.unlock_sequence);
	outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR);
	spin_unlock(&ie6xx_wdt_data.unlock_sequence);

	return 0;
}

static const struct watchdog_info ie6xx_wdt_info = {
	.identity =	"Intel Atom E6xx Watchdog",
	.options =	WDIOF_SETTIMEOUT |
			WDIOF_MAGICCLOSE |
			WDIOF_KEEPALIVEPING,
};

static const struct watchdog_ops ie6xx_wdt_ops = {
	.owner =	THIS_MODULE,
	.start =	ie6xx_wdt_start,
	.stop =		ie6xx_wdt_stop,
	.ping =		ie6xx_wdt_ping,
	.set_timeout =	ie6xx_wdt_set_timeout,
};

static struct watchdog_device ie6xx_wdt_dev = {
	.info =		&ie6xx_wdt_info,
	.ops =		&ie6xx_wdt_ops,
	.min_timeout =	MIN_TIME,
	.max_timeout =	MAX_TIME,
};

#ifdef CONFIG_DEBUG_FS

static int ie6xx_wdt_dbg_show(struct seq_file *s, void *unused)
{
	seq_printf(s, "PV1   = 0x%08x\n",
		inl(ie6xx_wdt_data.sch_wdtba + PV1));
	seq_printf(s, "PV2   = 0x%08x\n",
		inl(ie6xx_wdt_data.sch_wdtba + PV2));
	seq_printf(s, "RR    = 0x%08x\n",
		inw(ie6xx_wdt_data.sch_wdtba + RR0));
	seq_printf(s, "WDTCR = 0x%08x\n",
		inw(ie6xx_wdt_data.sch_wdtba + WDTCR));
	seq_printf(s, "DCR   = 0x%08x\n",
		inl(ie6xx_wdt_data.sch_wdtba + DCR));
	seq_printf(s, "WDTLR = 0x%08x\n",
		inw(ie6xx_wdt_data.sch_wdtba + WDTLR));

	seq_printf(s, "\n");
	return 0;
}

static int ie6xx_wdt_dbg_open(struct inode *inode, struct file *file)
{
	return single_open(file, ie6xx_wdt_dbg_show, NULL);
}

static const struct file_operations ie6xx_wdt_dbg_operations = {
	.open		= ie6xx_wdt_dbg_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static void ie6xx_wdt_debugfs_init(void)
{
	/* /sys/kernel/debug/ie6xx_wdt */
	ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt",
		S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_dbg_operations);
}

static void ie6xx_wdt_debugfs_exit(void)
{
	debugfs_remove(ie6xx_wdt_data.debugfs);
}

#else
static void ie6xx_wdt_debugfs_init(void)
{
}

static void ie6xx_wdt_debugfs_exit(void)
{
}
#endif

static int ie6xx_wdt_probe(struct platform_device *pdev)
{
	struct resource *res;
	u8 wdtlr;
	int ret;

	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
	if (!res)
		return -ENODEV;

	if (!request_region(res->start, resource_size(res), pdev->name)) {
		dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n",
			(u64)res->start);
		return -EBUSY;
	}

	ie6xx_wdt_data.sch_wdtba = res->start;
	dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba);

	ie6xx_wdt_dev.timeout = timeout;
	watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout);

	spin_lock_init(&ie6xx_wdt_data.unlock_sequence);

	wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR);
	if (wdtlr & WDT_LOCK)
		dev_warn(&pdev->dev,
			"Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr);

	ie6xx_wdt_debugfs_init();

	ret = watchdog_register_device(&ie6xx_wdt_dev);
	if (ret) {
		dev_err(&pdev->dev,
			"Watchdog timer: cannot register device (err =%d)\n",
									ret);
		goto misc_register_error;
	}

	return 0;

misc_register_error:
	ie6xx_wdt_debugfs_exit();
	release_region(res->start, resource_size(res));
	ie6xx_wdt_data.sch_wdtba = 0;
	return ret;
}

static int __devexit ie6xx_wdt_remove(struct platform_device *pdev)
{
	struct resource *res;

	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
	ie6xx_wdt_stop(NULL);
	watchdog_unregister_device(&ie6xx_wdt_dev);
	ie6xx_wdt_debugfs_exit();
	release_region(res->start, resource_size(res));
	ie6xx_wdt_data.sch_wdtba = 0;

	return 0;
}

static struct platform_driver ie6xx_wdt_driver = {
	.probe		= ie6xx_wdt_probe,
	.remove		= ie6xx_wdt_remove,
	.driver		= {
		.name	= DRIVER_NAME,
		.owner	= THIS_MODULE,
	},
};

static int __init ie6xx_wdt_init(void)
{
	/* Check boot parameters to verify that their initial values */
	/* are in range. */
	if ((timeout < MIN_TIME) ||
	    (timeout > MAX_TIME)) {
		pr_err("Watchdog timer: value of timeout %d (dec) "
		  "is out of range from %d to %d (dec)\n",
		  timeout, MIN_TIME, MAX_TIME);
		return -EINVAL;
	}

	return platform_driver_register(&ie6xx_wdt_driver);
}

static void __exit ie6xx_wdt_exit(void)
{
	platform_driver_unregister(&ie6xx_wdt_driver);
}

late_initcall(ie6xx_wdt_init);
module_exit(ie6xx_wdt_exit);

MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:" DRIVER_NAME);