summaryrefslogtreecommitdiffstats
path: root/drivers/char/watchdog/rm9k_wdt.c
blob: b4678839d3bbaf4ca7dbb7f17968a0944c712369 (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
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
/*
 *  Watchdog implementation for GPI h/w found on PMC-Sierra RM9xxx
 *  chips.
 *
 *  Copyright (C) 2004 by Basler Vision Technologies AG
 *  Author: Thomas Koeller <thomas.koeller@baslerweb.com>
 *
 *  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.
 *
 *  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
 */

#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/notifier.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/rm9k-ocd.h>

#include <rm9k_wdt.h>


#define CLOCK                  125000000
#define MAX_TIMEOUT_SECONDS    32
#define CPCCR                  0x0080
#define CPGIG1SR               0x0044
#define CPGIG1ER               0x0054


/* Function prototypes */
static irqreturn_t wdt_gpi_irqhdl(int, void *);
static void wdt_gpi_start(void);
static void wdt_gpi_stop(void);
static void wdt_gpi_set_timeout(unsigned int);
static int wdt_gpi_open(struct inode *, struct file *);
static int wdt_gpi_release(struct inode *, struct file *);
static ssize_t wdt_gpi_write(struct file *, const char __user *, size_t, loff_t *);
static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
static const struct resource *wdt_gpi_get_resource(struct platform_device *, const char *, unsigned int);
static int __init wdt_gpi_probe(struct device *);
static int __exit wdt_gpi_remove(struct device *);


static const char wdt_gpi_name[] = "wdt_gpi";
static atomic_t opencnt;
static int expect_close;
static int locked;


/* These are set from device resources */
static void __iomem * wd_regs;
static unsigned int wd_irq, wd_ctr;


/* Module arguments */
static int timeout = MAX_TIMEOUT_SECONDS;
module_param(timeout, int, 0444);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");

static unsigned long resetaddr = 0xbffdc200;
module_param(resetaddr, ulong, 0444);
MODULE_PARM_DESC(resetaddr, "Address to write to to force a reset");

static unsigned long flagaddr = 0xbffdc104;
module_param(flagaddr, ulong, 0444);
MODULE_PARM_DESC(flagaddr, "Address to write to boot flags to");

static int powercycle;
module_param(powercycle, bool, 0444);
MODULE_PARM_DESC(powercycle, "Cycle power if watchdog expires");

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0444);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be disabled once started");


/* Kernel interfaces */
static const struct file_operations fops = {
	.owner		= THIS_MODULE,
	.open		= wdt_gpi_open,
	.release	= wdt_gpi_release,
	.write		= wdt_gpi_write,
	.unlocked_ioctl	= wdt_gpi_ioctl,
};

static struct miscdevice miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= wdt_gpi_name,
	.fops		= &fops,
};

static struct notifier_block wdt_gpi_shutdown = {
	.notifier_call	= wdt_gpi_notify,
};


/* Interrupt handler */
static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt)
{
	if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
		return IRQ_NONE;
	__raw_writel(0x1, wd_regs + 0x0008);


	printk(KERN_CRIT "%s: watchdog expired - resetting system\n",
		wdt_gpi_name);

	*(volatile char *) flagaddr |= 0x01;
	*(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
	iob();
	while (1)
		cpu_relax();
}


/* Watchdog functions */
static void wdt_gpi_start(void)
{
	u32 reg;

	lock_titan_regs();
	reg = titan_readl(CPGIG1ER);
	titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
	iob();
	unlock_titan_regs();
}

static void wdt_gpi_stop(void)
{
	u32 reg;

	lock_titan_regs();
	reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
	titan_writel(reg, CPCCR);
	reg = titan_readl(CPGIG1ER);
	titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
	iob();
	unlock_titan_regs();
}

static void wdt_gpi_set_timeout(unsigned int to)
{
	u32 reg;
	const u32 wdval = (to * CLOCK) & ~0x0000000f;

	lock_titan_regs();
	reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
	titan_writel(reg, CPCCR);
	wmb();
	__raw_writel(wdval, wd_regs + 0x0000);
	wmb();
	titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
	wmb();
	titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
	iob();
	unlock_titan_regs();
}


/* /dev/watchdog operations */
static int wdt_gpi_open(struct inode *inode, struct file *file)
{
	int res;

	if (unlikely(atomic_dec_if_positive(&opencnt) < 0))
		return -EBUSY;

	expect_close = 0;
	if (locked) {
		module_put(THIS_MODULE);
		free_irq(wd_irq, &miscdev);
		locked = 0;
	}

	res = request_irq(wd_irq, wdt_gpi_irqhdl, SA_SHIRQ | SA_INTERRUPT,
			  wdt_gpi_name, &miscdev);
	if (unlikely(res))
		return res;

	wdt_gpi_set_timeout(timeout);
	wdt_gpi_start();

	printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
		wdt_gpi_name, timeout);
	return nonseekable_open(inode, file);
}

static int wdt_gpi_release(struct inode *inode, struct file *file)
{
	if (nowayout) {
		printk(KERN_INFO "%s: no way out - watchdog left running\n",
			wdt_gpi_name);
		__module_get(THIS_MODULE);
		locked = 1;
	} else {
		if (expect_close) {
			wdt_gpi_stop();
			free_irq(wd_irq, &miscdev);
			printk(KERN_INFO "%s: watchdog stopped\n", wdt_gpi_name);
		} else {
			printk(KERN_CRIT "%s: unexpected close() -"
				" watchdog left running\n",
				wdt_gpi_name);
			wdt_gpi_set_timeout(timeout);
			__module_get(THIS_MODULE);
			locked = 1;
		}
	}

	atomic_inc(&opencnt);
	return 0;
}

static ssize_t
wdt_gpi_write(struct file *f, const char __user *d, size_t s, loff_t *o)
{
	char val;

	wdt_gpi_set_timeout(timeout);
	expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
	return s ? 1 : 0;
}

static long
wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
{
	long res = -ENOTTY;
	const long size = _IOC_SIZE(cmd);
	int stat;
	void __user *argp = (void __user *)arg;
	static struct watchdog_info wdinfo = {
		.identity               = "RM9xxx/GPI watchdog",
		.firmware_version       = 0,
		.options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
	};

	if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
		return -ENOTTY;

	if ((_IOC_DIR(cmd) & _IOC_READ)
	    && !access_ok(VERIFY_WRITE, arg, size))
		return -EFAULT;

	if ((_IOC_DIR(cmd) & _IOC_WRITE)
	    && !access_ok(VERIFY_READ, arg, size))
		return -EFAULT;

	expect_close = 0;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		wdinfo.options = nowayout ?
			WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
			WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
		res = __copy_to_user(argp, &wdinfo, size) ?  -EFAULT : size;
		break;

	case WDIOC_GETSTATUS:
		break;

	case WDIOC_GETBOOTSTATUS:
		stat = (*(volatile char *) flagaddr & 0x01)
			? WDIOF_CARDRESET : 0;
		res = __copy_to_user(argp, &stat, size) ?
			-EFAULT : size;
		break;

	case WDIOC_SETOPTIONS:
		break;

	case WDIOC_KEEPALIVE:
		wdt_gpi_set_timeout(timeout);
		res = size;
		break;

	case WDIOC_SETTIMEOUT:
		{
			int val;
			if (unlikely(__copy_from_user(&val, argp, size))) {
				res = -EFAULT;
				break;
			}

			if (val > MAX_TIMEOUT_SECONDS)
				val = MAX_TIMEOUT_SECONDS;
			timeout = val;
			wdt_gpi_set_timeout(val);
			res = size;
			printk(KERN_INFO "%s: timeout set to %u seconds\n",
				wdt_gpi_name, timeout);
		}
		break;

	case WDIOC_GETTIMEOUT:
		res = __copy_to_user(argp, &timeout, size) ?
			-EFAULT : size;
		break;
	}

	return res;
}


/* Shutdown notifier */
static int
wdt_gpi_notify(struct notifier_block *this, unsigned long code, void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		wdt_gpi_stop();

	return NOTIFY_DONE;
}


/* Init & exit procedures */
static const struct resource *
wdt_gpi_get_resource(struct platform_device *pdv, const char *name,
		      unsigned int type)
{
	char buf[80];
	if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
		return NULL;
	return platform_get_resource_byname(pdv, type, buf);
}

/* No hotplugging on the platform bus - use __init */
static int __init wdt_gpi_probe(struct device *dev)
{
	int res;
	struct platform_device * const pdv = to_platform_device(dev);
	const struct resource
		* const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
						  IORESOURCE_MEM),
		* const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
						  IORESOURCE_IRQ),
		* const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
						  0);

	if (unlikely(!rr || !ri || !rc))
		return -ENXIO;

	wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
	if (unlikely(!wd_regs))
		return -ENOMEM;
	wd_irq = ri->start;
	wd_ctr = rc->start;
	res = misc_register(&miscdev);
	if (res)
		iounmap(wd_regs);
	else
		register_reboot_notifier(&wdt_gpi_shutdown);
	return res;
}

static int __exit wdt_gpi_remove(struct device *dev)
{
	int res;

	unregister_reboot_notifier(&wdt_gpi_shutdown);
	res = misc_deregister(&miscdev);
	iounmap(wd_regs);
	wd_regs = NULL;
	return res;
}


/* Device driver init & exit */
static struct device_driver wdt_gpi_driver = {
	.name		= (char *) wdt_gpi_name,
	.bus		= &platform_bus_type,
	.owner		= THIS_MODULE,
	.probe		= wdt_gpi_probe,
	.remove		= __exit_p(wdt_gpi_remove),
	.shutdown	= NULL,
	.suspend	= NULL,
	.resume		= NULL,
};

static int __init wdt_gpi_init_module(void)
{
	atomic_set(&opencnt, 1);
	if (timeout > MAX_TIMEOUT_SECONDS)
		timeout = MAX_TIMEOUT_SECONDS;
	return driver_register(&wdt_gpi_driver);
}

static void __exit wdt_gpi_cleanup_module(void)
{
	driver_unregister(&wdt_gpi_driver);
}

module_init(wdt_gpi_init_module);
module_exit(wdt_gpi_cleanup_module);

MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
MODULE_VERSION("0.1");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

OpenPOWER on IntegriCloud