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1/*
2 * Watchdog driver for the mpcore watchdog timer
3 *
4 * (c) Copyright 2004 ARM Limited
5 *
6 * Based on the SoftDog driver:
7 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
8 * All Rights Reserved.
9 *
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>
24#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>
31#include <linux/platform_device.h>
32#include <linux/uaccess.h>
33#include <linux/slab.h>
34#include <linux/io.h>
35
36#include <asm/smp_twd.h>
37
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;
48static DEFINE_SPINLOCK(wdt_lock);
49
50#define TIMER_MARGIN 60
51static int mpcore_margin = TIMER_MARGIN;
52module_param(mpcore_margin, int, 0);
53MODULE_PARM_DESC(mpcore_margin,
54 "MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
55 __MODULE_STRING(TIMER_MARGIN) ")");
56
57static int nowayout = WATCHDOG_NOWAYOUT;
58module_param(nowayout, int, 0);
59MODULE_PARM_DESC(nowayout,
60 "Watchdog cannot be stopped once started (default="
61 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
62
63#define ONLY_TESTING 0
64static int mpcore_noboot = ONLY_TESTING;
65module_param(mpcore_noboot, int, 0);
66MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, "
67 "set to 1 to ignore reboots, 0 to reboot (default="
68 __MODULE_STRING(ONLY_TESTING) ")");
69
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 */
74static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
75{
76 struct mpcore_wdt *wdt = arg;
77
78 /* Check it really was our interrupt */
79 if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
80 dev_printk(KERN_CRIT, wdt->dev,
81 "Triggered - Reboot ignored.\n");
82 /* Clear the interrupt on the watchdog */
83 writel(1, wdt->base + TWD_WDOG_INTSTAT);
84 return IRQ_HANDLED;
85 }
86 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{
98 unsigned long count;
99
100 spin_lock(&wdt_lock);
101 /* Assume prescale is set to 256 */
102 count = __raw_readl(wdt->base + TWD_WDOG_COUNTER);
103 count = (0xFFFFFFFFU - count) * (HZ / 5);
104 count = (count / 256) * mpcore_margin;
105
106 /* Reload the counter */
107 writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
108 wdt->perturb = wdt->perturb ? 0 : 1;
109 spin_unlock(&wdt_lock);
110}
111
112static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
113{
114 spin_lock(&wdt_lock);
115 writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
116 writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
117 writel(0x0, wdt->base + TWD_WDOG_CONTROL);
118 spin_unlock(&wdt_lock);
119}
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{
151 struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_dev);
152
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.
175 * Lock it in if it's a module and we set nowayout
176 */
177 if (wdt->expect_close == 42)
178 mpcore_wdt_stop(wdt);
179 else {
180 dev_printk(KERN_CRIT, wdt->dev,
181 "unexpected close, not stopping watchdog!\n");
182 mpcore_wdt_keepalive(wdt);
183 }
184 clear_bit(0, &wdt->timer_alive);
185 wdt->expect_close = 0;
186 return 0;
187}
188
189static ssize_t mpcore_wdt_write(struct file *file, const char *data,
190 size_t len, loff_t *ppos)
191{
192 struct mpcore_wdt *wdt = file->private_data;
193
194 /*
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
218static const struct watchdog_info ident = {
219 .options = WDIOF_SETTIMEOUT |
220 WDIOF_KEEPALIVEPING |
221 WDIOF_MAGICCLOSE,
222 .identity = "MPcore Watchdog",
223};
224
225static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
226 unsigned long arg)
227{
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))
236 return -ENOTTY;
237
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
250 case WDIOC_GETSTATUS:
251 case WDIOC_GETBOOTSTATUS:
252 uarg.i = 0;
253 ret = 0;
254 break;
255
256 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
268 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:
286 return -ENOTTY;
287 }
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 */
301static void mpcore_wdt_shutdown(struct platform_device *dev)
302{
303 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
304
305 if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
306 mpcore_wdt_stop(wdt);
307}
308
309/*
310 * Kernel Interfaces
311 */
312static const struct file_operations mpcore_wdt_fops = {
313 .owner = THIS_MODULE,
314 .llseek = no_llseek,
315 .write = mpcore_wdt_write,
316 .unlocked_ioctl = mpcore_wdt_ioctl,
317 .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
327static int __devinit mpcore_wdt_probe(struct platform_device *dev)
328{
329 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
343 wdt = kzalloc(sizeof(struct mpcore_wdt), GFP_KERNEL);
344 if (!wdt) {
345 ret = -ENOMEM;
346 goto err_out;
347 }
348
349 wdt->dev = &dev->dev;
350 wdt->irq = platform_get_irq(dev, 0);
351 if (wdt->irq < 0) {
352 ret = -ENXIO;
353 goto err_free;
354 }
355 wdt->base = ioremap(res->start, resource_size(res));
356 if (!wdt->base) {
357 ret = -ENOMEM;
358 goto err_free;
359 }
360
361 mpcore_wdt_miscdev.parent = &dev->dev;
362 ret = misc_register(&mpcore_wdt_miscdev);
363 if (ret) {
364 dev_printk(KERN_ERR, wdt->dev,
365 "cannot register miscdev on minor=%d (err=%d)\n",
366 WATCHDOG_MINOR, ret);
367 goto err_misc;
368 }
369
370 ret = request_irq(wdt->irq, mpcore_wdt_fire, IRQF_DISABLED,
371 "mpcore_wdt", wdt);
372 if (ret) {
373 dev_printk(KERN_ERR, wdt->dev,
374 "cannot register IRQ%d for watchdog\n", wdt->irq);
375 goto err_irq;
376 }
377
378 mpcore_wdt_stop(wdt);
379 platform_set_drvdata(dev, wdt);
380 mpcore_wdt_dev = dev;
381
382 return 0;
383
384err_irq:
385 misc_deregister(&mpcore_wdt_miscdev);
386err_misc:
387 iounmap(wdt->base);
388err_free:
389 kfree(wdt);
390err_out:
391 return ret;
392}
393
394static int __devexit mpcore_wdt_remove(struct platform_device *dev)
395{
396 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
397
398 platform_set_drvdata(dev, NULL);
399
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
410#ifdef CONFIG_PM
411static int mpcore_wdt_suspend(struct platform_device *dev, pm_message_t msg)
412{
413 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
414 mpcore_wdt_stop(wdt); /* Turn the WDT off */
415 return 0;
416}
417
418static int mpcore_wdt_resume(struct platform_device *dev)
419{
420 struct mpcore_wdt *wdt = platform_get_drvdata(dev);
421 /* re-activate timer */
422 if (test_bit(0, &wdt->timer_alive))
423 mpcore_wdt_start(wdt);
424 return 0;
425}
426#else
427#define mpcore_wdt_suspend NULL
428#define mpcore_wdt_resume NULL
429#endif
430
431/* work with hotplug and coldplug */
432MODULE_ALIAS("platform:mpcore_wdt");
433
434static struct platform_driver mpcore_wdt_driver = {
435 .probe = mpcore_wdt_probe,
436 .remove = __devexit_p(mpcore_wdt_remove),
437 .suspend = mpcore_wdt_suspend,
438 .resume = mpcore_wdt_resume,
439 .shutdown = mpcore_wdt_shutdown,
440 .driver = {
441 .owner = THIS_MODULE,
442 .name = "mpcore_wdt",
443 },
444};
445
446static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. "
447 "mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n";
448
449static int __init mpcore_wdt_init(void)
450{
451 /*
452 * Check that the margin value is within it's range;
453 * if not reset to the default
454 */
455 if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
456 mpcore_wdt_set_heartbeat(TIMER_MARGIN);
457 printk(KERN_INFO "mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
458 TIMER_MARGIN);
459 }
460
461 printk(banner, mpcore_noboot, mpcore_margin, nowayout);
462
463 return platform_driver_register(&mpcore_wdt_driver);
464}
465
466static void __exit mpcore_wdt_exit(void)
467{
468 platform_driver_unregister(&mpcore_wdt_driver);
469}
470
471module_init(mpcore_wdt_init);
472module_exit(mpcore_wdt_exit);
473
474MODULE_AUTHOR("ARM Limited");
475MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
476MODULE_LICENSE("GPL");
477MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);