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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 */
Joe Perches27c766a2012-02-15 15:06:19 -080022
23#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24
Russell Kingb9d36b82005-09-12 22:56:56 +010025#include <linux/module.h>
26#include <linux/moduleparam.h>
Russell Kingb9d36b82005-09-12 22:56:56 +010027#include <linux/types.h>
28#include <linux/miscdevice.h>
29#include <linux/watchdog.h>
30#include <linux/fs.h>
31#include <linux/reboot.h>
32#include <linux/init.h>
33#include <linux/interrupt.h>
Russell Kingd052d1b2005-10-29 19:07:23 +010034#include <linux/platform_device.h>
Alan Cox83ab1a52008-05-19 14:07:15 +010035#include <linux/uaccess.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090036#include <linux/slab.h>
Srinidhi Kasagar98af0572010-05-12 05:53:26 +010037#include <linux/io.h>
Russell Kingad4162f2005-09-14 09:56:38 +010038
Srinidhi Kasagar98af0572010-05-12 05:53:26 +010039#include <asm/smp_twd.h>
Russell Kingb9d36b82005-09-12 22:56:56 +010040
41struct mpcore_wdt {
42 unsigned long timer_alive;
43 struct device *dev;
44 void __iomem *base;
45 int irq;
46 unsigned int perturb;
47 char expect_close;
48};
49
Viresh Kumaraa065772012-03-12 09:51:58 +053050static struct platform_device *mpcore_wdt_pdev;
Srinidhi Kasagar98af0572010-05-12 05:53:26 +010051static DEFINE_SPINLOCK(wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +010052
53#define TIMER_MARGIN 60
54static int mpcore_margin = TIMER_MARGIN;
55module_param(mpcore_margin, int, 0);
Alan Cox83ab1a52008-05-19 14:07:15 +010056MODULE_PARM_DESC(mpcore_margin,
57 "MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
58 __MODULE_STRING(TIMER_MARGIN) ")");
Russell Kingb9d36b82005-09-12 22:56:56 +010059
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010060static bool nowayout = WATCHDOG_NOWAYOUT;
61module_param(nowayout, bool, 0);
Alan Cox83ab1a52008-05-19 14:07:15 +010062MODULE_PARM_DESC(nowayout,
63 "Watchdog cannot be stopped once started (default="
64 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Russell Kingb9d36b82005-09-12 22:56:56 +010065
66#define ONLY_TESTING 0
67static int mpcore_noboot = ONLY_TESTING;
68module_param(mpcore_noboot, int, 0);
Wim Van Sebroecka77dba72009-04-14 20:20:07 +000069MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, "
70 "set to 1 to ignore reboots, 0 to reboot (default="
71 __MODULE_STRING(ONLY_TESTING) ")");
Russell Kingb9d36b82005-09-12 22:56:56 +010072
73/*
74 * This is the interrupt handler. Note that we only use this
75 * in testing mode, so don't actually do a reboot here.
76 */
David Howells7d12e782006-10-05 14:55:46 +010077static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
Russell Kingb9d36b82005-09-12 22:56:56 +010078{
79 struct mpcore_wdt *wdt = arg;
80
81 /* Check it really was our interrupt */
82 if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
Alan Cox83ab1a52008-05-19 14:07:15 +010083 dev_printk(KERN_CRIT, wdt->dev,
84 "Triggered - Reboot ignored.\n");
Russell Kingb9d36b82005-09-12 22:56:56 +010085 /* Clear the interrupt on the watchdog */
86 writel(1, wdt->base + TWD_WDOG_INTSTAT);
Russell Kingb9d36b82005-09-12 22:56:56 +010087 return IRQ_HANDLED;
88 }
Russell Kingb9d36b82005-09-12 22:56:56 +010089 return IRQ_NONE;
90}
91
92/*
93 * mpcore_wdt_keepalive - reload the timer
94 *
95 * Note that the spec says a DIFFERENT value must be written to the reload
96 * register each time. The "perturb" variable deals with this by adding 1
97 * to the count every other time the function is called.
98 */
99static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
100{
Srinidhi Kasagar98af0572010-05-12 05:53:26 +0100101 unsigned long count;
Russell Kingb9d36b82005-09-12 22:56:56 +0100102
Srinidhi Kasagar98af0572010-05-12 05:53:26 +0100103 spin_lock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100104 /* Assume prescale is set to 256 */
Srinidhi Kasagar98af0572010-05-12 05:53:26 +0100105 count = __raw_readl(wdt->base + TWD_WDOG_COUNTER);
106 count = (0xFFFFFFFFU - count) * (HZ / 5);
107 count = (count / 256) * mpcore_margin;
Russell Kingb9d36b82005-09-12 22:56:56 +0100108
109 /* Reload the counter */
110 writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
Russell Kingb9d36b82005-09-12 22:56:56 +0100111 wdt->perturb = wdt->perturb ? 0 : 1;
Alan Cox83ab1a52008-05-19 14:07:15 +0100112 spin_unlock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100113}
114
115static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
116{
Alan Cox83ab1a52008-05-19 14:07:15 +0100117 spin_lock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100118 writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
119 writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
120 writel(0x0, wdt->base + TWD_WDOG_CONTROL);
Alan Cox83ab1a52008-05-19 14:07:15 +0100121 spin_unlock(&wdt_lock);
Russell Kingb9d36b82005-09-12 22:56:56 +0100122}
123
124static void mpcore_wdt_start(struct mpcore_wdt *wdt)
125{
126 dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n");
127
128 /* This loads the count register but does NOT start the count yet */
129 mpcore_wdt_keepalive(wdt);
130
131 if (mpcore_noboot) {
132 /* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
133 writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
134 } else {
135 /* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
136 writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
137 }
138}
139
140static int mpcore_wdt_set_heartbeat(int t)
141{
142 if (t < 0x0001 || t > 0xFFFF)
143 return -EINVAL;
144
145 mpcore_margin = t;
146 return 0;
147}
148
149/*
150 * /dev/watchdog handling
151 */
152static int mpcore_wdt_open(struct inode *inode, struct file *file)
153{
Viresh Kumaraa065772012-03-12 09:51:58 +0530154 struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_pdev);
Russell Kingb9d36b82005-09-12 22:56:56 +0100155
156 if (test_and_set_bit(0, &wdt->timer_alive))
157 return -EBUSY;
158
159 if (nowayout)
160 __module_get(THIS_MODULE);
161
162 file->private_data = wdt;
163
164 /*
165 * Activate timer
166 */
167 mpcore_wdt_start(wdt);
168
169 return nonseekable_open(inode, file);
170}
171
172static int mpcore_wdt_release(struct inode *inode, struct file *file)
173{
174 struct mpcore_wdt *wdt = file->private_data;
175
176 /*
177 * Shut off the timer.
Wim Van Sebroeck5f3b2752011-02-23 20:04:38 +0000178 * Lock it in if it's a module and we set nowayout
Russell Kingb9d36b82005-09-12 22:56:56 +0100179 */
Alan Cox83ab1a52008-05-19 14:07:15 +0100180 if (wdt->expect_close == 42)
Russell Kingb9d36b82005-09-12 22:56:56 +0100181 mpcore_wdt_stop(wdt);
Alan Cox83ab1a52008-05-19 14:07:15 +0100182 else {
183 dev_printk(KERN_CRIT, wdt->dev,
184 "unexpected close, not stopping watchdog!\n");
Russell Kingb9d36b82005-09-12 22:56:56 +0100185 mpcore_wdt_keepalive(wdt);
186 }
187 clear_bit(0, &wdt->timer_alive);
188 wdt->expect_close = 0;
189 return 0;
190}
191
Alan Cox83ab1a52008-05-19 14:07:15 +0100192static ssize_t mpcore_wdt_write(struct file *file, const char *data,
193 size_t len, loff_t *ppos)
Russell Kingb9d36b82005-09-12 22:56:56 +0100194{
195 struct mpcore_wdt *wdt = file->private_data;
196
Russell Kingb9d36b82005-09-12 22:56:56 +0100197 /*
198 * Refresh the timer.
199 */
200 if (len) {
201 if (!nowayout) {
202 size_t i;
203
204 /* In case it was set long ago */
205 wdt->expect_close = 0;
206
207 for (i = 0; i != len; i++) {
208 char c;
209
210 if (get_user(c, data + i))
211 return -EFAULT;
212 if (c == 'V')
213 wdt->expect_close = 42;
214 }
215 }
216 mpcore_wdt_keepalive(wdt);
217 }
218 return len;
219}
220
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000221static const struct watchdog_info ident = {
Russell Kingb9d36b82005-09-12 22:56:56 +0100222 .options = WDIOF_SETTIMEOUT |
223 WDIOF_KEEPALIVEPING |
224 WDIOF_MAGICCLOSE,
225 .identity = "MPcore Watchdog",
226};
227
Alan Cox83ab1a52008-05-19 14:07:15 +0100228static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
229 unsigned long arg)
Russell Kingb9d36b82005-09-12 22:56:56 +0100230{
231 struct mpcore_wdt *wdt = file->private_data;
232 int ret;
233 union {
234 struct watchdog_info ident;
235 int i;
236 } uarg;
237
238 if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200239 return -ENOTTY;
Russell Kingb9d36b82005-09-12 22:56:56 +0100240
241 if (_IOC_DIR(cmd) & _IOC_WRITE) {
242 ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
243 if (ret)
244 return -EFAULT;
245 }
246
247 switch (cmd) {
248 case WDIOC_GETSUPPORT:
249 uarg.ident = ident;
250 ret = 0;
251 break;
252
Wim Van Sebroeck0c06090c2008-07-18 11:41:17 +0000253 case WDIOC_GETSTATUS:
254 case WDIOC_GETBOOTSTATUS:
255 uarg.i = 0;
256 ret = 0;
257 break;
258
Russell Kingb9d36b82005-09-12 22:56:56 +0100259 case WDIOC_SETOPTIONS:
260 ret = -EINVAL;
261 if (uarg.i & WDIOS_DISABLECARD) {
262 mpcore_wdt_stop(wdt);
263 ret = 0;
264 }
265 if (uarg.i & WDIOS_ENABLECARD) {
266 mpcore_wdt_start(wdt);
267 ret = 0;
268 }
269 break;
270
Russell Kingb9d36b82005-09-12 22:56:56 +0100271 case WDIOC_KEEPALIVE:
272 mpcore_wdt_keepalive(wdt);
273 ret = 0;
274 break;
275
276 case WDIOC_SETTIMEOUT:
277 ret = mpcore_wdt_set_heartbeat(uarg.i);
278 if (ret)
279 break;
280
281 mpcore_wdt_keepalive(wdt);
282 /* Fall */
283 case WDIOC_GETTIMEOUT:
284 uarg.i = mpcore_margin;
285 ret = 0;
286 break;
287
288 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200289 return -ENOTTY;
Russell Kingb9d36b82005-09-12 22:56:56 +0100290 }
291
292 if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
293 ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
294 if (ret)
295 ret = -EFAULT;
296 }
297 return ret;
298}
299
300/*
301 * System shutdown handler. Turn off the watchdog if we're
302 * restarting or halting the system.
303 */
Viresh Kumaraa065772012-03-12 09:51:58 +0530304static void mpcore_wdt_shutdown(struct platform_device *pdev)
Russell Kingb9d36b82005-09-12 22:56:56 +0100305{
Viresh Kumaraa065772012-03-12 09:51:58 +0530306 struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
Russell Kingb9d36b82005-09-12 22:56:56 +0100307
308 if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
309 mpcore_wdt_stop(wdt);
310}
311
312/*
313 * Kernel Interfaces
314 */
Arjan van de Ven62322d22006-07-03 00:24:21 -0700315static const struct file_operations mpcore_wdt_fops = {
Russell Kingb9d36b82005-09-12 22:56:56 +0100316 .owner = THIS_MODULE,
317 .llseek = no_llseek,
318 .write = mpcore_wdt_write,
Alan Cox83ab1a52008-05-19 14:07:15 +0100319 .unlocked_ioctl = mpcore_wdt_ioctl,
Russell Kingb9d36b82005-09-12 22:56:56 +0100320 .open = mpcore_wdt_open,
321 .release = mpcore_wdt_release,
322};
323
324static struct miscdevice mpcore_wdt_miscdev = {
325 .minor = WATCHDOG_MINOR,
326 .name = "watchdog",
327 .fops = &mpcore_wdt_fops,
328};
329
Viresh Kumaraa065772012-03-12 09:51:58 +0530330static int __devinit mpcore_wdt_probe(struct platform_device *pdev)
Russell Kingb9d36b82005-09-12 22:56:56 +0100331{
Russell Kingb9d36b82005-09-12 22:56:56 +0100332 struct mpcore_wdt *wdt;
333 struct resource *res;
334 int ret;
335
336 /* We only accept one device, and it must have an id of -1 */
Viresh Kumaraa065772012-03-12 09:51:58 +0530337 if (pdev->id != -1)
Russell Kingb9d36b82005-09-12 22:56:56 +0100338 return -ENODEV;
339
Viresh Kumaraa065772012-03-12 09:51:58 +0530340 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Viresh Kumar75f5a532012-03-12 09:51:59 +0530341 if (!res)
342 return -ENODEV;
Russell Kingb9d36b82005-09-12 22:56:56 +0100343
Viresh Kumar75f5a532012-03-12 09:51:59 +0530344 wdt = devm_kzalloc(&pdev->dev, sizeof(struct mpcore_wdt), GFP_KERNEL);
345 if (!wdt)
346 return -ENOMEM;
Russell Kingb9d36b82005-09-12 22:56:56 +0100347
Viresh Kumaraa065772012-03-12 09:51:58 +0530348 wdt->dev = &pdev->dev;
349 wdt->irq = platform_get_irq(pdev, 0);
Viresh Kumar60a1aa52012-03-12 09:52:00 +0530350 if (wdt->irq >= 0) {
351 ret = devm_request_irq(wdt->dev, wdt->irq, mpcore_wdt_fire, 0,
352 "mpcore_wdt", wdt);
353 if (ret) {
354 dev_printk(KERN_ERR, wdt->dev,
355 "cannot register IRQ%d for watchdog\n",
356 wdt->irq);
357 return ret;
358 }
David Vrabel48944732006-01-19 17:56:29 +0000359 }
Viresh Kumar75f5a532012-03-12 09:51:59 +0530360
361 wdt->base = devm_ioremap(wdt->dev, res->start, resource_size(res));
362 if (!wdt->base)
363 return -ENOMEM;
Russell Kingb9d36b82005-09-12 22:56:56 +0100364
Viresh Kumaraa065772012-03-12 09:51:58 +0530365 mpcore_wdt_miscdev.parent = &pdev->dev;
Russell Kingb9d36b82005-09-12 22:56:56 +0100366 ret = misc_register(&mpcore_wdt_miscdev);
367 if (ret) {
Srinidhi Kasagar98af0572010-05-12 05:53:26 +0100368 dev_printk(KERN_ERR, wdt->dev,
Alan Cox83ab1a52008-05-19 14:07:15 +0100369 "cannot register miscdev on minor=%d (err=%d)\n",
370 WATCHDOG_MINOR, ret);
Viresh Kumar75f5a532012-03-12 09:51:59 +0530371 return ret;
Russell Kingb9d36b82005-09-12 22:56:56 +0100372 }
373
374 mpcore_wdt_stop(wdt);
Viresh Kumaraa065772012-03-12 09:51:58 +0530375 platform_set_drvdata(pdev, wdt);
376 mpcore_wdt_pdev = pdev;
Russell Kingb9d36b82005-09-12 22:56:56 +0100377
378 return 0;
Russell Kingb9d36b82005-09-12 22:56:56 +0100379}
380
Viresh Kumaraa065772012-03-12 09:51:58 +0530381static int __devexit mpcore_wdt_remove(struct platform_device *pdev)
Russell Kingb9d36b82005-09-12 22:56:56 +0100382{
Viresh Kumaraa065772012-03-12 09:51:58 +0530383 platform_set_drvdata(pdev, NULL);
Russell Kingb9d36b82005-09-12 22:56:56 +0100384
385 misc_deregister(&mpcore_wdt_miscdev);
386
Viresh Kumaraa065772012-03-12 09:51:58 +0530387 mpcore_wdt_pdev = NULL;
Russell Kingb9d36b82005-09-12 22:56:56 +0100388
Russell Kingb9d36b82005-09-12 22:56:56 +0100389 return 0;
390}
391
Peter Fordham641e4f42011-06-15 13:18:32 -0700392#ifdef CONFIG_PM
Viresh Kumaraa065772012-03-12 09:51:58 +0530393static int mpcore_wdt_suspend(struct platform_device *pdev, pm_message_t msg)
Peter Fordham641e4f42011-06-15 13:18:32 -0700394{
Viresh Kumaraa065772012-03-12 09:51:58 +0530395 struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
Peter Fordham641e4f42011-06-15 13:18:32 -0700396 mpcore_wdt_stop(wdt); /* Turn the WDT off */
397 return 0;
398}
399
Viresh Kumaraa065772012-03-12 09:51:58 +0530400static int mpcore_wdt_resume(struct platform_device *pdev)
Peter Fordham641e4f42011-06-15 13:18:32 -0700401{
Viresh Kumaraa065772012-03-12 09:51:58 +0530402 struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
Peter Fordham641e4f42011-06-15 13:18:32 -0700403 /* re-activate timer */
404 if (test_bit(0, &wdt->timer_alive))
405 mpcore_wdt_start(wdt);
406 return 0;
407}
408#else
409#define mpcore_wdt_suspend NULL
410#define mpcore_wdt_resume NULL
411#endif
412
Kay Sieversf37d1932008-04-10 21:29:23 -0700413/* work with hotplug and coldplug */
414MODULE_ALIAS("platform:mpcore_wdt");
415
Russell King3ae5eae2005-11-09 22:32:44 +0000416static struct platform_driver mpcore_wdt_driver = {
Russell Kingb9d36b82005-09-12 22:56:56 +0100417 .probe = mpcore_wdt_probe,
418 .remove = __devexit_p(mpcore_wdt_remove),
Peter Fordham641e4f42011-06-15 13:18:32 -0700419 .suspend = mpcore_wdt_suspend,
420 .resume = mpcore_wdt_resume,
Russell Kingb9d36b82005-09-12 22:56:56 +0100421 .shutdown = mpcore_wdt_shutdown,
Russell King3ae5eae2005-11-09 22:32:44 +0000422 .driver = {
423 .owner = THIS_MODULE,
424 .name = "mpcore_wdt",
425 },
Russell Kingb9d36b82005-09-12 22:56:56 +0100426};
427
Russell Kingb9d36b82005-09-12 22:56:56 +0100428static int __init mpcore_wdt_init(void)
429{
430 /*
431 * Check that the margin value is within it's range;
432 * if not reset to the default
433 */
434 if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
435 mpcore_wdt_set_heartbeat(TIMER_MARGIN);
Joe Perches27c766a2012-02-15 15:06:19 -0800436 pr_info("mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
Russell Kingb9d36b82005-09-12 22:56:56 +0100437 TIMER_MARGIN);
438 }
439
Joe Perches27c766a2012-02-15 15:06:19 -0800440 pr_info("MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n",
441 mpcore_noboot, mpcore_margin, nowayout);
Russell Kingb9d36b82005-09-12 22:56:56 +0100442
Russell King3ae5eae2005-11-09 22:32:44 +0000443 return platform_driver_register(&mpcore_wdt_driver);
Russell Kingb9d36b82005-09-12 22:56:56 +0100444}
445
446static void __exit mpcore_wdt_exit(void)
447{
Russell King3ae5eae2005-11-09 22:32:44 +0000448 platform_driver_unregister(&mpcore_wdt_driver);
Russell Kingb9d36b82005-09-12 22:56:56 +0100449}
450
451module_init(mpcore_wdt_init);
452module_exit(mpcore_wdt_exit);
453
454MODULE_AUTHOR("ARM Limited");
455MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
456MODULE_LICENSE("GPL");
457MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);