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Bryan Wu1e6d3202007-07-15 02:50:02 +08001/*
2 * Blackfin On-Chip Watchdog Driver
3 * Supports BF53[123]/BF53[467]/BF54[2489]/BF561
4 *
5 * Originally based on softdog.c
6 * Copyright 2006-2007 Analog Devices Inc.
7 * Copyright 2006-2007 Michele d'Amico
Alan Cox29fa0582008-10-27 15:17:56 +00008 * Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
Bryan Wu1e6d3202007-07-15 02:50:02 +08009 *
10 * Enter bugs at http://blackfin.uclinux.org/
11 *
12 * Licensed under the GPL-2 or later.
13 */
14
15#include <linux/platform_device.h>
16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/types.h>
19#include <linux/timer.h>
20#include <linux/miscdevice.h>
21#include <linux/watchdog.h>
22#include <linux/fs.h>
23#include <linux/notifier.h>
24#include <linux/reboot.h>
25#include <linux/init.h>
26#include <linux/interrupt.h>
Alan Cox9a5f50d2008-05-19 14:06:30 +010027#include <linux/uaccess.h>
Wim Van Sebroeck089ab072008-07-15 11:46:11 +000028#include <asm/blackfin.h>
Bryan Wu1e6d3202007-07-15 02:50:02 +080029
30#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
31#define stampit() stamp("here i am")
Mike Frysinger93539b12008-03-27 11:53:32 -070032#define pr_devinit(fmt, args...) ({ static const __devinitconst char __fmt[] = fmt; printk(__fmt, ## args); })
33#define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); })
Bryan Wu1e6d3202007-07-15 02:50:02 +080034
35#define WATCHDOG_NAME "bfin-wdt"
36#define PFX WATCHDOG_NAME ": "
37
38/* The BF561 has two watchdogs (one per core), but since Linux
39 * only runs on core A, we'll just work with that one.
40 */
41#ifdef BF561_FAMILY
42# define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL()
43# define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT()
44# define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT()
45# define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x)
46# define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x)
47# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
48#endif
49
50/* Bit in SWRST that indicates boot caused by watchdog */
51#define SWRST_RESET_WDOG 0x4000
52
53/* Bit in WDOG_CTL that indicates watchdog has expired (WDR0) */
54#define WDOG_EXPIRED 0x8000
55
56/* Masks for WDEV field in WDOG_CTL register */
57#define ICTL_RESET 0x0
58#define ICTL_NMI 0x2
59#define ICTL_GPI 0x4
60#define ICTL_NONE 0x6
61#define ICTL_MASK 0x6
62
63/* Masks for WDEN field in WDOG_CTL register */
64#define WDEN_MASK 0x0FF0
65#define WDEN_ENABLE 0x0000
66#define WDEN_DISABLE 0x0AD0
67
68/* some defaults */
69#define WATCHDOG_TIMEOUT 20
70
71static unsigned int timeout = WATCHDOG_TIMEOUT;
72static int nowayout = WATCHDOG_NOWAYOUT;
73static struct watchdog_info bfin_wdt_info;
74static unsigned long open_check;
75static char expect_close;
Jiri Slabybf6350a2007-11-10 05:58:44 +010076static DEFINE_SPINLOCK(bfin_wdt_spinlock);
Bryan Wu1e6d3202007-07-15 02:50:02 +080077
78/**
79 * bfin_wdt_keepalive - Keep the Userspace Watchdog Alive
80 *
81 * The Userspace watchdog got a KeepAlive: schedule the next timeout.
82 */
83static int bfin_wdt_keepalive(void)
84{
85 stampit();
86 bfin_write_WDOG_STAT(0);
87 return 0;
88}
89
90/**
91 * bfin_wdt_stop - Stop the Watchdog
92 *
93 * Stops the on-chip watchdog.
94 */
95static int bfin_wdt_stop(void)
96{
97 stampit();
98 bfin_write_WDOG_CTL(WDEN_DISABLE);
99 return 0;
100}
101
102/**
103 * bfin_wdt_start - Start the Watchdog
104 *
105 * Starts the on-chip watchdog. Automatically loads WDOG_CNT
106 * into WDOG_STAT for us.
107 */
108static int bfin_wdt_start(void)
109{
110 stampit();
111 bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET);
112 return 0;
113}
114
115/**
116 * bfin_wdt_running - Check Watchdog status
117 *
118 * See if the watchdog is running.
119 */
120static int bfin_wdt_running(void)
121{
122 stampit();
123 return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
124}
125
126/**
127 * bfin_wdt_set_timeout - Set the Userspace Watchdog timeout
128 * @t: new timeout value (in seconds)
129 *
130 * Translate the specified timeout in seconds into System Clock
131 * terms which is what the on-chip Watchdog requires.
132 */
133static int bfin_wdt_set_timeout(unsigned long t)
134{
135 u32 cnt;
136 unsigned long flags;
137
138 stampit();
139
140 cnt = t * get_sclk();
141 if (cnt < get_sclk()) {
142 printk(KERN_WARNING PFX "timeout value is too large\n");
143 return -EINVAL;
144 }
145
146 spin_lock_irqsave(&bfin_wdt_spinlock, flags);
147 {
148 int run = bfin_wdt_running();
149 bfin_wdt_stop();
150 bfin_write_WDOG_CNT(cnt);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100151 if (run)
152 bfin_wdt_start();
Bryan Wu1e6d3202007-07-15 02:50:02 +0800153 }
154 spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
155
156 timeout = t;
157
158 return 0;
159}
160
161/**
162 * bfin_wdt_open - Open the Device
163 * @inode: inode of device
164 * @file: file handle of device
165 *
166 * Watchdog device is opened and started.
167 */
168static int bfin_wdt_open(struct inode *inode, struct file *file)
169{
170 stampit();
171
172 if (test_and_set_bit(0, &open_check))
173 return -EBUSY;
174
175 if (nowayout)
176 __module_get(THIS_MODULE);
177
178 bfin_wdt_keepalive();
179 bfin_wdt_start();
180
181 return nonseekable_open(inode, file);
182}
183
184/**
185 * bfin_wdt_close - Close the Device
186 * @inode: inode of device
187 * @file: file handle of device
188 *
189 * Watchdog device is closed and stopped.
190 */
191static int bfin_wdt_release(struct inode *inode, struct file *file)
192{
193 stampit();
194
Alan Cox9a5f50d2008-05-19 14:06:30 +0100195 if (expect_close == 42)
Bryan Wu1e6d3202007-07-15 02:50:02 +0800196 bfin_wdt_stop();
Alan Cox9a5f50d2008-05-19 14:06:30 +0100197 else {
198 printk(KERN_CRIT PFX
199 "Unexpected close, not stopping watchdog!\n");
Bryan Wu1e6d3202007-07-15 02:50:02 +0800200 bfin_wdt_keepalive();
201 }
Bryan Wu1e6d3202007-07-15 02:50:02 +0800202 expect_close = 0;
203 clear_bit(0, &open_check);
Bryan Wu1e6d3202007-07-15 02:50:02 +0800204 return 0;
205}
206
207/**
208 * bfin_wdt_write - Write to Device
209 * @file: file handle of device
210 * @buf: buffer to write
211 * @count: length of buffer
212 * @ppos: offset
213 *
214 * Pings the watchdog on write.
215 */
216static ssize_t bfin_wdt_write(struct file *file, const char __user *data,
Alan Cox9a5f50d2008-05-19 14:06:30 +0100217 size_t len, loff_t *ppos)
Bryan Wu1e6d3202007-07-15 02:50:02 +0800218{
219 stampit();
220
221 if (len) {
222 if (!nowayout) {
223 size_t i;
224
225 /* In case it was set long ago */
226 expect_close = 0;
227
228 for (i = 0; i != len; i++) {
229 char c;
230 if (get_user(c, data + i))
231 return -EFAULT;
232 if (c == 'V')
233 expect_close = 42;
234 }
235 }
236 bfin_wdt_keepalive();
237 }
238
239 return len;
240}
241
242/**
243 * bfin_wdt_ioctl - Query Device
Bryan Wu1e6d3202007-07-15 02:50:02 +0800244 * @file: file handle of device
245 * @cmd: watchdog command
246 * @arg: argument
247 *
248 * Query basic information from the device or ping it, as outlined by the
249 * watchdog API.
250 */
Alan Cox9a5f50d2008-05-19 14:06:30 +0100251static long bfin_wdt_ioctl(struct file *file,
252 unsigned int cmd, unsigned long arg)
Bryan Wu1e6d3202007-07-15 02:50:02 +0800253{
254 void __user *argp = (void __user *)arg;
255 int __user *p = argp;
256
257 stampit();
258
259 switch (cmd) {
Alan Cox9a5f50d2008-05-19 14:06:30 +0100260 case WDIOC_GETSUPPORT:
261 if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
262 return -EFAULT;
263 else
Bryan Wu1e6d3202007-07-15 02:50:02 +0800264 return 0;
Alan Cox9a5f50d2008-05-19 14:06:30 +0100265 case WDIOC_GETSTATUS:
266 case WDIOC_GETBOOTSTATUS:
267 return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100268 case WDIOC_SETOPTIONS: {
269 unsigned long flags;
270 int options, ret = -EINVAL;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800271
Alan Cox9a5f50d2008-05-19 14:06:30 +0100272 if (get_user(options, p))
273 return -EFAULT;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800274
Alan Cox9a5f50d2008-05-19 14:06:30 +0100275 spin_lock_irqsave(&bfin_wdt_spinlock, flags);
276 if (options & WDIOS_DISABLECARD) {
277 bfin_wdt_stop();
278 ret = 0;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800279 }
Alan Cox9a5f50d2008-05-19 14:06:30 +0100280 if (options & WDIOS_ENABLECARD) {
281 bfin_wdt_start();
282 ret = 0;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800283 }
Alan Cox9a5f50d2008-05-19 14:06:30 +0100284 spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
285 return ret;
286 }
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000287 case WDIOC_KEEPALIVE:
288 bfin_wdt_keepalive();
289 return 0;
290 case WDIOC_SETTIMEOUT: {
291 int new_timeout;
292
293 if (get_user(new_timeout, p))
294 return -EFAULT;
295 if (bfin_wdt_set_timeout(new_timeout))
296 return -EINVAL;
297 }
298 /* Fall */
299 case WDIOC_GETTIMEOUT:
300 return put_user(timeout, p);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100301 default:
302 return -ENOTTY;
Bryan Wu1e6d3202007-07-15 02:50:02 +0800303 }
304}
305
306/**
307 * bfin_wdt_notify_sys - Notifier Handler
308 * @this: notifier block
309 * @code: notifier event
310 * @unused: unused
311 *
312 * Handles specific events, such as turning off the watchdog during a
313 * shutdown event.
314 */
Alan Cox9a5f50d2008-05-19 14:06:30 +0100315static int bfin_wdt_notify_sys(struct notifier_block *this,
316 unsigned long code, void *unused)
Bryan Wu1e6d3202007-07-15 02:50:02 +0800317{
318 stampit();
319
320 if (code == SYS_DOWN || code == SYS_HALT)
321 bfin_wdt_stop();
322
323 return NOTIFY_DONE;
324}
325
326#ifdef CONFIG_PM
327static int state_before_suspend;
328
329/**
330 * bfin_wdt_suspend - suspend the watchdog
331 * @pdev: device being suspended
332 * @state: requested suspend state
333 *
334 * Remember if the watchdog was running and stop it.
335 * TODO: is this even right? Doesn't seem to be any
336 * standard in the watchdog world ...
337 */
338static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
339{
340 stampit();
341
342 state_before_suspend = bfin_wdt_running();
343 bfin_wdt_stop();
344
345 return 0;
346}
347
348/**
349 * bfin_wdt_resume - resume the watchdog
350 * @pdev: device being resumed
351 *
352 * If the watchdog was running, turn it back on.
353 */
354static int bfin_wdt_resume(struct platform_device *pdev)
355{
356 stampit();
357
358 if (state_before_suspend) {
359 bfin_wdt_set_timeout(timeout);
360 bfin_wdt_start();
361 }
362
363 return 0;
364}
365#else
366# define bfin_wdt_suspend NULL
367# define bfin_wdt_resume NULL
368#endif
369
Jan Engelhardtb47a1662008-01-22 20:48:10 +0100370static const struct file_operations bfin_wdt_fops = {
Alan Cox9a5f50d2008-05-19 14:06:30 +0100371 .owner = THIS_MODULE,
372 .llseek = no_llseek,
373 .write = bfin_wdt_write,
374 .unlocked_ioctl = bfin_wdt_ioctl,
375 .open = bfin_wdt_open,
376 .release = bfin_wdt_release,
Bryan Wu1e6d3202007-07-15 02:50:02 +0800377};
378
379static struct miscdevice bfin_wdt_miscdev = {
380 .minor = WATCHDOG_MINOR,
381 .name = "watchdog",
382 .fops = &bfin_wdt_fops,
383};
384
385static struct watchdog_info bfin_wdt_info = {
386 .identity = "Blackfin Watchdog",
387 .options = WDIOF_SETTIMEOUT |
Alan Cox9a5f50d2008-05-19 14:06:30 +0100388 WDIOF_KEEPALIVEPING |
389 WDIOF_MAGICCLOSE,
Bryan Wu1e6d3202007-07-15 02:50:02 +0800390};
391
392static struct notifier_block bfin_wdt_notifier = {
393 .notifier_call = bfin_wdt_notify_sys,
394};
395
396/**
Mike Frysinger93539b12008-03-27 11:53:32 -0700397 * bfin_wdt_probe - Initialize module
398 *
399 * Registers the misc device and notifier handler. Actual device
400 * initialization is handled by bfin_wdt_open().
401 */
402static int __devinit bfin_wdt_probe(struct platform_device *pdev)
403{
404 int ret;
405
406 ret = register_reboot_notifier(&bfin_wdt_notifier);
407 if (ret) {
Alan Cox9a5f50d2008-05-19 14:06:30 +0100408 pr_devinit(KERN_ERR PFX
409 "cannot register reboot notifier (err=%d)\n", ret);
Mike Frysinger93539b12008-03-27 11:53:32 -0700410 return ret;
411 }
412
413 ret = misc_register(&bfin_wdt_miscdev);
414 if (ret) {
Alan Cox9a5f50d2008-05-19 14:06:30 +0100415 pr_devinit(KERN_ERR PFX
416 "cannot register miscdev on minor=%d (err=%d)\n",
417 WATCHDOG_MINOR, ret);
Mike Frysinger93539b12008-03-27 11:53:32 -0700418 unregister_reboot_notifier(&bfin_wdt_notifier);
419 return ret;
420 }
421
422 pr_devinit(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
423 timeout, nowayout);
424
425 return 0;
426}
427
428/**
429 * bfin_wdt_remove - Initialize module
430 *
431 * Unregisters the misc device and notifier handler. Actual device
432 * deinitialization is handled by bfin_wdt_close().
433 */
434static int __devexit bfin_wdt_remove(struct platform_device *pdev)
435{
436 misc_deregister(&bfin_wdt_miscdev);
437 unregister_reboot_notifier(&bfin_wdt_notifier);
438 return 0;
439}
440
441static struct platform_device *bfin_wdt_device;
442
443static struct platform_driver bfin_wdt_driver = {
444 .probe = bfin_wdt_probe,
445 .remove = __devexit_p(bfin_wdt_remove),
446 .suspend = bfin_wdt_suspend,
447 .resume = bfin_wdt_resume,
448 .driver = {
449 .name = WATCHDOG_NAME,
450 .owner = THIS_MODULE,
451 },
452};
453
454/**
Bryan Wu1e6d3202007-07-15 02:50:02 +0800455 * bfin_wdt_init - Initialize module
456 *
Mike Frysinger93539b12008-03-27 11:53:32 -0700457 * Checks the module params and registers the platform device & driver.
458 * Real work is in the platform probe function.
Bryan Wu1e6d3202007-07-15 02:50:02 +0800459 */
460static int __init bfin_wdt_init(void)
461{
462 int ret;
463
464 stampit();
465
466 /* Check that the timeout value is within range */
467 if (bfin_wdt_set_timeout(timeout))
468 return -EINVAL;
469
470 /* Since this is an on-chip device and needs no board-specific
471 * resources, we'll handle all the platform device stuff here.
472 */
Mike Frysinger93539b12008-03-27 11:53:32 -0700473 ret = platform_driver_register(&bfin_wdt_driver);
Bryan Wu1e6d3202007-07-15 02:50:02 +0800474 if (ret) {
Mike Frysinger93539b12008-03-27 11:53:32 -0700475 pr_init(KERN_ERR PFX "unable to register driver\n");
Bryan Wu1e6d3202007-07-15 02:50:02 +0800476 return ret;
477 }
478
Mike Frysinger93539b12008-03-27 11:53:32 -0700479 bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME, -1, NULL, 0);
480 if (IS_ERR(bfin_wdt_device)) {
481 pr_init(KERN_ERR PFX "unable to register device\n");
482 platform_driver_unregister(&bfin_wdt_driver);
483 return PTR_ERR(bfin_wdt_device);
Bryan Wu1e6d3202007-07-15 02:50:02 +0800484 }
485
Bryan Wu1e6d3202007-07-15 02:50:02 +0800486 return 0;
487}
488
489/**
490 * bfin_wdt_exit - Deinitialize module
491 *
Mike Frysinger93539b12008-03-27 11:53:32 -0700492 * Back out the platform device & driver steps. Real work is in the
493 * platform remove function.
Bryan Wu1e6d3202007-07-15 02:50:02 +0800494 */
495static void __exit bfin_wdt_exit(void)
496{
Mike Frysinger93539b12008-03-27 11:53:32 -0700497 platform_device_unregister(bfin_wdt_device);
498 platform_driver_unregister(&bfin_wdt_driver);
Bryan Wu1e6d3202007-07-15 02:50:02 +0800499}
500
501module_init(bfin_wdt_init);
502module_exit(bfin_wdt_exit);
503
504MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>");
505MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
506MODULE_LICENSE("GPL");
507MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
508
509module_param(timeout, uint, 0);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100510MODULE_PARM_DESC(timeout,
511 "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
512 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
Bryan Wu1e6d3202007-07-15 02:50:02 +0800513
514module_param(nowayout, int, 0);
Alan Cox9a5f50d2008-05-19 14:06:30 +0100515MODULE_PARM_DESC(nowayout,
516 "Watchdog cannot be stopped once started (default="
517 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");