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Russell Kingb9d36b82005-09-12 22:56:56 +01001/*
2 * Watchdog driver for the mpcore watchdog timer
3 *
4 * (c) Copyright 2004 ARM Limited
5 *
6 * Based on the SoftDog driver:
Alan Cox29fa0582008-10-27 15:17:56 +00007 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +00008 * All Rights Reserved.
Russell Kingb9d36b82005-09-12 22:56:56 +01009 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
16 * warranty for any of this software. This material is provided
17 * "AS-IS" and at no charge.
18 *
19 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
20 *
21 */
22#include <linux/module.h>
23#include <linux/moduleparam.h>
Russell Kingb9d36b82005-09-12 22:56:56 +010024#include <linux/types.h>
25#include <linux/miscdevice.h>
26#include <linux/watchdog.h>
27#include <linux/fs.h>
28#include <linux/reboot.h>
29#include <linux/init.h>
30#include <linux/interrupt.h>
Russell Kingd052d1b2005-10-29 19:07:23 +010031#include <linux/platform_device.h>
Alan Cox83ab1a52008-05-19 14:07:15 +010032#include <linux/uaccess.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090033#include <linux/slab.h>
Srinidhi Kasagar98af0572010-05-12 05:53:26 +010034#include <linux/io.h>
Russell Kingad4162f2005-09-14 09:56:38 +010035
Srinidhi Kasagar98af0572010-05-12 05:53:26 +010036#include <asm/smp_twd.h>
Russell Kingb9d36b82005-09-12 22:56:56 +010037
38struct mpcore_wdt {
39 unsigned long timer_alive;
40 struct device *dev;
41 void __iomem *base;
42 int irq;
43 unsigned int perturb;
44 char expect_close;
45};
46
47static struct platform_device *mpcore_wdt_dev;
Srinidhi Kasagar98af0572010-05-12 05:53:26 +010048static DEFINE_SPINLOCK(wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +010049
50#define TIMER_MARGIN 60
51static int mpcore_margin = TIMER_MARGIN;
52module_param(mpcore_margin, int, 0);
Alan Cox83ab1a52008-05-19 14:07:15 +010053MODULE_PARM_DESC(mpcore_margin,
54 "MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
55 __MODULE_STRING(TIMER_MARGIN) ")");
Russell Kingb9d36b82005-09-12 22:56:56 +010056
57static int nowayout = WATCHDOG_NOWAYOUT;
58module_param(nowayout, int, 0);
Alan Cox83ab1a52008-05-19 14:07:15 +010059MODULE_PARM_DESC(nowayout,
60 "Watchdog cannot be stopped once started (default="
61 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Russell Kingb9d36b82005-09-12 22:56:56 +010062
63#define ONLY_TESTING 0
64static int mpcore_noboot = ONLY_TESTING;
65module_param(mpcore_noboot, int, 0);
Wim Van Sebroecka77dba72009-04-14 20:20:07 +000066MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, "
67 "set to 1 to ignore reboots, 0 to reboot (default="
68 __MODULE_STRING(ONLY_TESTING) ")");
Russell Kingb9d36b82005-09-12 22:56:56 +010069
70/*
71 * This is the interrupt handler. Note that we only use this
72 * in testing mode, so don't actually do a reboot here.
73 */
David Howells7d12e782006-10-05 14:55:46 +010074static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
Russell Kingb9d36b82005-09-12 22:56:56 +010075{
76 struct mpcore_wdt *wdt = arg;
77
78 /* Check it really was our interrupt */
79 if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
Alan Cox83ab1a52008-05-19 14:07:15 +010080 dev_printk(KERN_CRIT, wdt->dev,
81 "Triggered - Reboot ignored.\n");
Russell Kingb9d36b82005-09-12 22:56:56 +010082 /* Clear the interrupt on the watchdog */
83 writel(1, wdt->base + TWD_WDOG_INTSTAT);
Russell Kingb9d36b82005-09-12 22:56:56 +010084 return IRQ_HANDLED;
85 }
Russell Kingb9d36b82005-09-12 22:56:56 +010086 return IRQ_NONE;
87}
88
89/*
90 * mpcore_wdt_keepalive - reload the timer
91 *
92 * Note that the spec says a DIFFERENT value must be written to the reload
93 * register each time. The "perturb" variable deals with this by adding 1
94 * to the count every other time the function is called.
95 */
96static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
97{
Srinidhi Kasagar98af0572010-05-12 05:53:26 +010098 unsigned long count;
Russell Kingb9d36b82005-09-12 22:56:56 +010099
Srinidhi Kasagar98af0572010-05-12 05:53:26 +0100100 spin_lock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100101 /* Assume prescale is set to 256 */
Srinidhi Kasagar98af0572010-05-12 05:53:26 +0100102 count = __raw_readl(wdt->base + TWD_WDOG_COUNTER);
103 count = (0xFFFFFFFFU - count) * (HZ / 5);
104 count = (count / 256) * mpcore_margin;
Russell Kingb9d36b82005-09-12 22:56:56 +0100105
106 /* Reload the counter */
107 writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
Russell Kingb9d36b82005-09-12 22:56:56 +0100108 wdt->perturb = wdt->perturb ? 0 : 1;
Alan Cox83ab1a52008-05-19 14:07:15 +0100109 spin_unlock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100110}
111
112static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
113{
Alan Cox83ab1a52008-05-19 14:07:15 +0100114 spin_lock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100115 writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
116 writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
117 writel(0x0, wdt->base + TWD_WDOG_CONTROL);
Alan Cox83ab1a52008-05-19 14:07:15 +0100118 spin_unlock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100119}
120
121static void mpcore_wdt_start(struct mpcore_wdt *wdt)
122{
123 dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n");
124
125 /* This loads the count register but does NOT start the count yet */
126 mpcore_wdt_keepalive(wdt);
127
128 if (mpcore_noboot) {
129 /* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
130 writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
131 } else {
132 /* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
133 writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
134 }
135}
136
137static int mpcore_wdt_set_heartbeat(int t)
138{
139 if (t < 0x0001 || t > 0xFFFF)
140 return -EINVAL;
141
142 mpcore_margin = t;
143 return 0;
144}
145
146/*
147 * /dev/watchdog handling
148 */
149static int mpcore_wdt_open(struct inode *inode, struct file *file)
150{
Russell King3ae5eae2005-11-09 22:32:44 +0000151 struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_dev);
Russell Kingb9d36b82005-09-12 22:56:56 +0100152
153 if (test_and_set_bit(0, &wdt->timer_alive))
154 return -EBUSY;
155
156 if (nowayout)
157 __module_get(THIS_MODULE);
158
159 file->private_data = wdt;
160
161 /*
162 * Activate timer
163 */
164 mpcore_wdt_start(wdt);
165
166 return nonseekable_open(inode, file);
167}
168
169static int mpcore_wdt_release(struct inode *inode, struct file *file)
170{
171 struct mpcore_wdt *wdt = file->private_data;
172
173 /*
174 * Shut off the timer.
Wim Van Sebroeck5f3b2752011-02-23 20:04:38 +0000175 * Lock it in if it's a module and we set nowayout
Russell Kingb9d36b82005-09-12 22:56:56 +0100176 */
Alan Cox83ab1a52008-05-19 14:07:15 +0100177 if (wdt->expect_close == 42)
Russell Kingb9d36b82005-09-12 22:56:56 +0100178 mpcore_wdt_stop(wdt);
Alan Cox83ab1a52008-05-19 14:07:15 +0100179 else {
180 dev_printk(KERN_CRIT, wdt->dev,
181 "unexpected close, not stopping watchdog!\n");
Russell Kingb9d36b82005-09-12 22:56:56 +0100182 mpcore_wdt_keepalive(wdt);
183 }
184 clear_bit(0, &wdt->timer_alive);
185 wdt->expect_close = 0;
186 return 0;
187}
188
Alan Cox83ab1a52008-05-19 14:07:15 +0100189static ssize_t mpcore_wdt_write(struct file *file, const char *data,
190 size_t len, loff_t *ppos)
Russell Kingb9d36b82005-09-12 22:56:56 +0100191{
192 struct mpcore_wdt *wdt = file->private_data;
193
Russell Kingb9d36b82005-09-12 22:56:56 +0100194 /*
195 * Refresh the timer.
196 */
197 if (len) {
198 if (!nowayout) {
199 size_t i;
200
201 /* In case it was set long ago */
202 wdt->expect_close = 0;
203
204 for (i = 0; i != len; i++) {
205 char c;
206
207 if (get_user(c, data + i))
208 return -EFAULT;
209 if (c == 'V')
210 wdt->expect_close = 42;
211 }
212 }
213 mpcore_wdt_keepalive(wdt);
214 }
215 return len;
216}
217
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000218static const struct watchdog_info ident = {
Russell Kingb9d36b82005-09-12 22:56:56 +0100219 .options = WDIOF_SETTIMEOUT |
220 WDIOF_KEEPALIVEPING |
221 WDIOF_MAGICCLOSE,
222 .identity = "MPcore Watchdog",
223};
224
Alan Cox83ab1a52008-05-19 14:07:15 +0100225static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
226 unsigned long arg)
Russell Kingb9d36b82005-09-12 22:56:56 +0100227{
228 struct mpcore_wdt *wdt = file->private_data;
229 int ret;
230 union {
231 struct watchdog_info ident;
232 int i;
233 } uarg;
234
235 if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200236 return -ENOTTY;
Russell Kingb9d36b82005-09-12 22:56:56 +0100237
238 if (_IOC_DIR(cmd) & _IOC_WRITE) {
239 ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
240 if (ret)
241 return -EFAULT;
242 }
243
244 switch (cmd) {
245 case WDIOC_GETSUPPORT:
246 uarg.ident = ident;
247 ret = 0;
248 break;
249
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000250 case WDIOC_GETSTATUS:
251 case WDIOC_GETBOOTSTATUS:
252 uarg.i = 0;
253 ret = 0;
254 break;
255
Russell Kingb9d36b82005-09-12 22:56:56 +0100256 case WDIOC_SETOPTIONS:
257 ret = -EINVAL;
258 if (uarg.i & WDIOS_DISABLECARD) {
259 mpcore_wdt_stop(wdt);
260 ret = 0;
261 }
262 if (uarg.i & WDIOS_ENABLECARD) {
263 mpcore_wdt_start(wdt);
264 ret = 0;
265 }
266 break;
267
Russell Kingb9d36b82005-09-12 22:56:56 +0100268 case WDIOC_KEEPALIVE:
269 mpcore_wdt_keepalive(wdt);
270 ret = 0;
271 break;
272
273 case WDIOC_SETTIMEOUT:
274 ret = mpcore_wdt_set_heartbeat(uarg.i);
275 if (ret)
276 break;
277
278 mpcore_wdt_keepalive(wdt);
279 /* Fall */
280 case WDIOC_GETTIMEOUT:
281 uarg.i = mpcore_margin;
282 ret = 0;
283 break;
284
285 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200286 return -ENOTTY;
Russell Kingb9d36b82005-09-12 22:56:56 +0100287 }
288
289 if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
290 ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
291 if (ret)
292 ret = -EFAULT;
293 }
294 return ret;
295}
296
297/*
298 * System shutdown handler. Turn off the watchdog if we're
299 * restarting or halting the system.
300 */
Russell King3ae5eae2005-11-09 22:32:44 +0000301static void mpcore_wdt_shutdown(struct platform_device *dev)
Russell Kingb9d36b82005-09-12 22:56:56 +0100302{
Russell King3ae5eae2005-11-09 22:32:44 +0000303 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
Russell Kingb9d36b82005-09-12 22:56:56 +0100304
305 if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
306 mpcore_wdt_stop(wdt);
307}
308
309/*
310 * Kernel Interfaces
311 */
Arjan van de Ven62322d22006-07-03 00:24:21 -0700312static const struct file_operations mpcore_wdt_fops = {
Russell Kingb9d36b82005-09-12 22:56:56 +0100313 .owner = THIS_MODULE,
314 .llseek = no_llseek,
315 .write = mpcore_wdt_write,
Alan Cox83ab1a52008-05-19 14:07:15 +0100316 .unlocked_ioctl = mpcore_wdt_ioctl,
Russell Kingb9d36b82005-09-12 22:56:56 +0100317 .open = mpcore_wdt_open,
318 .release = mpcore_wdt_release,
319};
320
321static struct miscdevice mpcore_wdt_miscdev = {
322 .minor = WATCHDOG_MINOR,
323 .name = "watchdog",
324 .fops = &mpcore_wdt_fops,
325};
326
Russell King3ae5eae2005-11-09 22:32:44 +0000327static int __devinit mpcore_wdt_probe(struct platform_device *dev)
Russell Kingb9d36b82005-09-12 22:56:56 +0100328{
Russell Kingb9d36b82005-09-12 22:56:56 +0100329 struct mpcore_wdt *wdt;
330 struct resource *res;
331 int ret;
332
333 /* We only accept one device, and it must have an id of -1 */
334 if (dev->id != -1)
335 return -ENODEV;
336
337 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
338 if (!res) {
339 ret = -ENODEV;
340 goto err_out;
341 }
342
Yoann Padioleaudd00cc42007-07-19 01:49:03 -0700343 wdt = kzalloc(sizeof(struct mpcore_wdt), GFP_KERNEL);
Russell Kingb9d36b82005-09-12 22:56:56 +0100344 if (!wdt) {
345 ret = -ENOMEM;
346 goto err_out;
347 }
Russell Kingb9d36b82005-09-12 22:56:56 +0100348
349 wdt->dev = &dev->dev;
350 wdt->irq = platform_get_irq(dev, 0);
David Vrabel48944732006-01-19 17:56:29 +0000351 if (wdt->irq < 0) {
352 ret = -ENXIO;
353 goto err_free;
354 }
H Hartley Sweetenb782a562009-12-04 12:24:04 -0500355 wdt->base = ioremap(res->start, resource_size(res));
Russell Kingb9d36b82005-09-12 22:56:56 +0100356 if (!wdt->base) {
357 ret = -ENOMEM;
358 goto err_free;
359 }
360
Andrew Victore0b79e02006-12-04 15:56:18 +0200361 mpcore_wdt_miscdev.parent = &dev->dev;
Russell Kingb9d36b82005-09-12 22:56:56 +0100362 ret = misc_register(&mpcore_wdt_miscdev);
363 if (ret) {
Srinidhi Kasagar98af0572010-05-12 05:53:26 +0100364 dev_printk(KERN_ERR, wdt->dev,
Alan Cox83ab1a52008-05-19 14:07:15 +0100365 "cannot register miscdev on minor=%d (err=%d)\n",
366 WATCHDOG_MINOR, ret);
Russell Kingb9d36b82005-09-12 22:56:56 +0100367 goto err_misc;
368 }
369
Alan Cox83ab1a52008-05-19 14:07:15 +0100370 ret = request_irq(wdt->irq, mpcore_wdt_fire, IRQF_DISABLED,
371 "mpcore_wdt", wdt);
Russell Kingb9d36b82005-09-12 22:56:56 +0100372 if (ret) {
Srinidhi Kasagar98af0572010-05-12 05:53:26 +0100373 dev_printk(KERN_ERR, wdt->dev,
Alan Cox83ab1a52008-05-19 14:07:15 +0100374 "cannot register IRQ%d for watchdog\n", wdt->irq);
Russell Kingb9d36b82005-09-12 22:56:56 +0100375 goto err_irq;
376 }
377
378 mpcore_wdt_stop(wdt);
Srinidhi Kasagar98af0572010-05-12 05:53:26 +0100379 platform_set_drvdata(dev, wdt);
Russell Kingb9d36b82005-09-12 22:56:56 +0100380 mpcore_wdt_dev = dev;
381
382 return 0;
383
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000384err_irq:
Russell Kingb9d36b82005-09-12 22:56:56 +0100385 misc_deregister(&mpcore_wdt_miscdev);
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000386err_misc:
Russell Kingb9d36b82005-09-12 22:56:56 +0100387 iounmap(wdt->base);
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000388err_free:
Russell Kingb9d36b82005-09-12 22:56:56 +0100389 kfree(wdt);
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000390err_out:
Russell Kingb9d36b82005-09-12 22:56:56 +0100391 return ret;
392}
393
Russell King3ae5eae2005-11-09 22:32:44 +0000394static int __devexit mpcore_wdt_remove(struct platform_device *dev)
Russell Kingb9d36b82005-09-12 22:56:56 +0100395{
Russell King3ae5eae2005-11-09 22:32:44 +0000396 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
Russell Kingb9d36b82005-09-12 22:56:56 +0100397
Russell King3ae5eae2005-11-09 22:32:44 +0000398 platform_set_drvdata(dev, NULL);
Russell Kingb9d36b82005-09-12 22:56:56 +0100399
400 misc_deregister(&mpcore_wdt_miscdev);
401
402 mpcore_wdt_dev = NULL;
403
404 free_irq(wdt->irq, wdt);
405 iounmap(wdt->base);
406 kfree(wdt);
407 return 0;
408}
409
Kay Sieversf37d1932008-04-10 21:29:23 -0700410/* work with hotplug and coldplug */
411MODULE_ALIAS("platform:mpcore_wdt");
412
Russell King3ae5eae2005-11-09 22:32:44 +0000413static struct platform_driver mpcore_wdt_driver = {
Russell Kingb9d36b82005-09-12 22:56:56 +0100414 .probe = mpcore_wdt_probe,
415 .remove = __devexit_p(mpcore_wdt_remove),
416 .shutdown = mpcore_wdt_shutdown,
Russell King3ae5eae2005-11-09 22:32:44 +0000417 .driver = {
418 .owner = THIS_MODULE,
419 .name = "mpcore_wdt",
420 },
Russell Kingb9d36b82005-09-12 22:56:56 +0100421};
422
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000423static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. "
424 "mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n";
Russell Kingb9d36b82005-09-12 22:56:56 +0100425
426static int __init mpcore_wdt_init(void)
427{
428 /*
429 * Check that the margin value is within it's range;
430 * if not reset to the default
431 */
432 if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
433 mpcore_wdt_set_heartbeat(TIMER_MARGIN);
Alan Cox83ab1a52008-05-19 14:07:15 +0100434 printk(KERN_INFO "mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
Russell Kingb9d36b82005-09-12 22:56:56 +0100435 TIMER_MARGIN);
436 }
437
438 printk(banner, mpcore_noboot, mpcore_margin, nowayout);
439
Russell King3ae5eae2005-11-09 22:32:44 +0000440 return platform_driver_register(&mpcore_wdt_driver);
Russell Kingb9d36b82005-09-12 22:56:56 +0100441}
442
443static void __exit mpcore_wdt_exit(void)
444{
Russell King3ae5eae2005-11-09 22:32:44 +0000445 platform_driver_unregister(&mpcore_wdt_driver);
Russell Kingb9d36b82005-09-12 22:56:56 +0100446}
447
448module_init(mpcore_wdt_init);
449module_exit(mpcore_wdt_exit);
450
451MODULE_AUTHOR("ARM Limited");
452MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
453MODULE_LICENSE("GPL");
454MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);