Root/target/linux/ubicom32/files/drivers/watchdog/ubi32_wdt.c

1/*
2 * drivers/watchdog/ubi32_wdt.c
3 * Ubicom32 Watchdog Driver
4 *
5 * Originally based on softdog.c
6 * Copyright 2006-2007 Analog Devices Inc.
7 * Copyright 2006-2007 Michele d'Amico
8 * Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
9 * (C) Copyright 2009, Ubicom, Inc.
10 *
11 * This file is part of the Ubicom32 Linux Kernel Port.
12 *
13 * The Ubicom32 Linux Kernel Port is free software: you can redistribute
14 * it and/or modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation, either version 2 of the
16 * License, or (at your option) any later version.
17 *
18 * The Ubicom32 Linux Kernel Port is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
21 * the GNU General Public License for more details.
22 *
23 * You should have received a copy of the GNU General Public License
24 * along with the Ubicom32 Linux Kernel Port. If not,
25 * see <http://www.gnu.org/licenses/>.
26 *
27 * Ubicom32 implementation derived from (with many thanks):
28 * arch/m68knommu
29 * arch/blackfin
30 * arch/parisc
31 */
32#include <linux/platform_device.h>
33#include <linux/module.h>
34#include <linux/moduleparam.h>
35#include <linux/types.h>
36#include <linux/timer.h>
37#include <linux/miscdevice.h>
38#include <linux/watchdog.h>
39#include <linux/fs.h>
40#include <linux/notifier.h>
41#include <linux/reboot.h>
42#include <linux/init.h>
43#include <linux/interrupt.h>
44#include <linux/uaccess.h>
45#include <asm/ip5000.h>
46
47#define WATCHDOG_NAME "ubi32-wdt"
48#define PFX WATCHDOG_NAME ": "
49
50#define OSC1_FREQ 12000000
51#define WATCHDOG_SEC_TO_CYC(x) (OSC1_FREQ * (x))
52#define WATCHDOG_MAX_SEC (0xffffffff / OSC1_FREQ)
53
54#define MIN_PROCESSOR_ADDRESS 0x03000000
55
56static DEFINE_SPINLOCK(ubi32_wdt_spinlock);
57
58#define WATCHDOG_TIMEOUT 20
59
60#if defined(CONFIG_WATCHDOG_NOWAYOUT)
61#define WATCHDOG_NOWAYOUT 1
62#else
63#define WATCHDOG_NOWAYOUT 0
64#endif
65
66static unsigned int timeout = WATCHDOG_TIMEOUT;
67static int nowayout = WATCHDOG_NOWAYOUT;
68static struct watchdog_info ubi32_wdt_info;
69static unsigned long open_check;
70static char expect_close;
71
72#if !defined(CONFIG_SMP)
73#define UBI32_WDT_LOCK(lock, flags) local_irq_save(flags)
74#define UBI32_WDT_UNLOCK(lock, flags) local_irq_restore(flags)
75#define UBI32_WDT_LOCK_CHECK()
76#else
77#define UBI32_WDT_LOCK(lock, flags) spin_lock_irqsave((lock), (flags));
78#define UBI32_WDT_UNLOCK(lock, flags) spin_unlock_irqrestore((lock), (flags));
79#define UBI32_WDT_LOCK_CHECK() BUG_ON(!spin_is_locked(&ubi32_wdt_spinlock));
80#endif
81
82/*
83 * ubi32_wdt_remaining()
84 * Return the approximate number of seconds remaining
85 */
86static int ubi32_wdt_remaining(void)
87{
88    int compare;
89    int curr;
90
91    UBI32_WDT_LOCK_CHECK();
92
93    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
94    compare = ubicom32_read_reg(&UBICOM32_IO_TIMER->wdcom);
95    curr = ubicom32_read_reg(&UBICOM32_IO_TIMER->mptval);
96    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
97    return (compare - curr) / OSC1_FREQ;
98
99}
100
101/*
102 * ubi32_wdt_keepalive()
103 * Keep the Userspace Watchdog Alive
104 *
105 * The Userspace watchdog got a KeepAlive: schedule the next timeout.
106 */
107static int ubi32_wdt_keepalive(void)
108{
109    UBI32_WDT_LOCK_CHECK();
110    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
111    ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcom,
112            ubicom32_read_reg(&UBICOM32_IO_TIMER->mptval)
113            + WATCHDOG_SEC_TO_CYC(timeout));
114    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
115    return 0;
116}
117
118/*
119 * ubi32_wdt_stop()
120 * Stop the on-chip Watchdog
121 */
122static int ubi32_wdt_stop(void)
123{
124    UBI32_WDT_LOCK_CHECK();
125    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
126    ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcfg, TIMER_WATCHDOG_DISABLE);
127    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
128    return 0;
129}
130
131/*
132 * ubi32_wdt_start()
133 * Start the on-chip Watchdog
134 */
135static int ubi32_wdt_start(void)
136{
137    UBI32_WDT_LOCK_CHECK();
138    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
139    ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcom,
140            ubicom32_read_reg(&UBICOM32_IO_TIMER->mptval)
141            + WATCHDOG_SEC_TO_CYC(timeout));
142    ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcfg, ~TIMER_WATCHDOG_DISABLE);
143    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
144    return 0;
145}
146
147/*
148 * ubi32_wdt_running()
149 * Return true if the watchdog is configured
150 */
151static int ubi32_wdt_running(void)
152{
153    int enabled;
154
155    UBI32_WDT_LOCK_CHECK();
156    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
157    enabled = ubicom32_read_reg(&UBICOM32_IO_TIMER->wdcfg) == ~TIMER_WATCHDOG_DISABLE;
158    ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
159    return enabled;
160}
161
162/*
163 * ubi32_wdt_set_timeout()
164 * Set the Userspace Watchdog timeout
165 *
166 * - @t: new timeout value (in seconds)
167 */
168static int ubi32_wdt_set_timeout(unsigned long t)
169{
170    UBI32_WDT_LOCK_CHECK();
171
172    if (t > WATCHDOG_MAX_SEC) {
173        printk(KERN_WARNING PFX "request to large: %ld [1-%d] sec)\n", t, WATCHDOG_MAX_SEC);
174        return -EINVAL;
175    }
176
177    /*
178     * If we are running, then reset the time value so
179     * that the new value has an immediate effect.
180     */
181    timeout = t;
182    if (ubi32_wdt_running()) {
183        ubi32_wdt_keepalive();
184    }
185    return 0;
186}
187
188/*
189 * ubi32_wdt_open()
190 * Open the Device
191 */
192static int ubi32_wdt_open(struct inode *inode, struct file *file)
193{
194    unsigned long flags;
195
196    if (test_and_set_bit(0, &open_check))
197        return -EBUSY;
198
199    if (nowayout)
200        __module_get(THIS_MODULE);
201
202    spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
203    ubi32_wdt_start();
204    spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
205
206    return nonseekable_open(inode, file);
207}
208
209/*
210 * ubi32_wdt_close()
211 * Close the Device
212 */
213static int ubi32_wdt_release(struct inode *inode, struct file *file)
214{
215    unsigned long flags;
216
217    /*
218     * If we don't expect a close, then the watchdog continues
219     * even though the device is closed. The caller will have
220     * a full timeout value to reopen the device and continue
221     * stroking it.
222     */
223    if (expect_close != 42) {
224        printk(KERN_CRIT PFX
225            "Unexpected close, not stopping watchdog!\n");
226        spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
227        ubi32_wdt_keepalive();
228        spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
229    } else {
230        spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
231        ubi32_wdt_stop();
232        spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
233    }
234
235    expect_close = 0;
236    clear_bit(0, &open_check);
237    return 0;
238}
239
240/*
241 * ubi32_wdt_write()
242 * Write to Device
243 *
244 * If the user writes nothing, nothing happens.
245 * If the user writes a V, then we expect a close and allow a release.
246 * If the user writes anything else, it is ignored.
247 */
248static ssize_t ubi32_wdt_write(struct file *file, const char __user *data,
249                        size_t len, loff_t *ppos)
250{
251    size_t i;
252    unsigned long flags;
253
254    /*
255     * Every write resets the expect_close. The last write
256     * must be a V to allow shutdown on close.
257     */
258    expect_close = 0;
259
260    /*
261     * Empty writes still ping.
262     */
263    if (!len) {
264        goto ping;
265    }
266
267    /*
268     * If nowayout is set, it does not matter if the caller
269     * is trying to send the magic 'V' we will not allow a
270     * close to stop us.
271     */
272    if (nowayout) {
273        goto ping;
274    }
275
276    /*
277     * See if the program wrote a 'V' and if so disable
278     * the watchdog on release.
279     */
280    for (i = 0; i < len; i++) {
281        char c;
282        if (get_user(c, data + i)) {
283            return -EFAULT;
284        }
285
286        if (c == 'V') {
287            expect_close = 42;
288        }
289    }
290
291ping:
292    spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
293    ubi32_wdt_keepalive();
294    spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
295    return len;
296}
297
298/*
299 * ubi32_wdt_ioctl()
300 * Query the watchdog device.
301 *
302 * Query basic information from the device or ping it, as outlined by the
303 * watchdog API.
304 */
305static long ubi32_wdt_ioctl(struct file *file,
306                unsigned int cmd, unsigned long arg)
307{
308    void __user *argp = (void __user *)arg;
309    int __user *p = argp;
310
311    switch (cmd) {
312    case WDIOC_GETSUPPORT:
313        if (copy_to_user(argp, &ubi32_wdt_info, sizeof(ubi32_wdt_info))) {
314            return -EFAULT;
315        }
316        return 0;
317
318    case WDIOC_GETSTATUS: {
319        unsigned long flags;
320        int running;
321
322        spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
323        running = ubi32_wdt_running();
324        spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
325        return running;
326    }
327
328    case WDIOC_GETBOOTSTATUS:
329        return ubicom32_get_reset_reason();
330
331    case WDIOC_SETOPTIONS: {
332        unsigned long flags;
333        int options, ret = -EINVAL;
334
335        /*
336         * The sample application does not pass a pointer
337         * but directly passes a value of 1 or 2; however
338         * all of the implementations (and thus probably
339         * the real applications) pass a pointer to a value.
340         *
341         * It should be noted that WDIOC_SETOPTIONS is defined as
342         * _IOR(WATCHDOG_IOCTL_BASE, 4, int), which means
343         * that it should be an int and NOT a pointer.
344         *
345         * TODO: Examine this code for future chips.
346         * TODO: Report the sample code defect.
347         */
348        if ((int)p < MIN_PROCESSOR_ADDRESS) {
349            options = (int)p;
350        } else {
351            if (get_user(options, p))
352            return -EFAULT;
353        }
354
355        spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
356        if (options & WDIOS_DISABLECARD) {
357            ubi32_wdt_stop();
358            ret = 0;
359        }
360        if (options & WDIOS_ENABLECARD) {
361            ubi32_wdt_start();
362            ret = 0;
363        }
364        spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
365        return ret;
366    }
367
368    case WDIOC_KEEPALIVE: {
369        unsigned long flags;
370
371        spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
372        ubi32_wdt_keepalive();
373        spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
374        return 0;
375    }
376
377    case WDIOC_SETTIMEOUT: {
378        int new_timeout;
379        unsigned long flags;
380        int ret = 0;
381
382        if (get_user(new_timeout, p))
383            return -EFAULT;
384
385        spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
386        ret = ubi32_wdt_set_timeout(new_timeout);
387        spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
388        return ret;
389
390    }
391
392    case WDIOC_GETTIMEOUT:
393        return put_user(timeout, p);
394
395    case WDIOC_GETTIMELEFT: {
396        unsigned long flags;
397        int remaining = 0;
398
399        spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
400        remaining = ubi32_wdt_remaining();
401        spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
402        return put_user(remaining, p);
403    }
404
405    default:
406        return -ENOTTY;
407    }
408}
409
410/*
411 * ubi32_wdt_notify_sys()
412 * Notification callback function for system events.
413 *
414 * Turn off the watchdog during a SYS_DOWN or SYS_HALT.
415 */
416static int ubi32_wdt_notify_sys(struct notifier_block *this,
417                    unsigned long code, void *unused)
418{
419    if (code == SYS_DOWN || code == SYS_HALT) {
420        unsigned long flags;
421
422        spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
423        ubi32_wdt_stop();
424        spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
425    }
426
427    return NOTIFY_DONE;
428}
429
430#ifdef CONFIG_PM
431static int state_before_suspend;
432
433/*
434 * ubi32_wdt_suspend()
435 * suspend the watchdog
436 *
437 * Remember if the watchdog was running and stop it.
438 */
439static int ubi32_wdt_suspend(struct platform_device *pdev, pm_message_t state)
440{
441    unsigned long flags;
442    spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
443    state_before_suspend = ubi32_wdt_running();
444    ubi32_wdt_stop();
445    spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
446
447    return 0;
448}
449
450/*
451 * ubi32_wdt_resume()
452 * Resume the watchdog
453 *
454 * If the watchdog was running, turn it back on.
455 */
456static int ubi32_wdt_resume(struct platform_device *pdev)
457{
458    if (state_before_suspend) {
459        unsigned long flags;
460        spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
461        ubi32_wdt_set_timeout(timeout);
462        ubi32_wdt_start();
463        spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
464    }
465
466    return 0;
467}
468#else
469# define ubi32_wdt_suspend NULL
470# define ubi32_wdt_resume NULL
471#endif
472
473static const struct file_operations ubi32_wdt_fops = {
474    .owner = THIS_MODULE,
475    .llseek = no_llseek,
476    .write = ubi32_wdt_write,
477    .unlocked_ioctl = ubi32_wdt_ioctl,
478    .open = ubi32_wdt_open,
479    .release = ubi32_wdt_release,
480};
481
482static struct miscdevice ubi32_wdt_miscdev = {
483    .minor = WATCHDOG_MINOR,
484    .name = "watchdog",
485    .fops = &ubi32_wdt_fops,
486};
487
488static struct watchdog_info ubi32_wdt_info = {
489    .identity = "Ubicom32 Watchdog",
490    .options = WDIOF_SETTIMEOUT |
491            WDIOF_KEEPALIVEPING |
492            WDIOF_MAGICCLOSE,
493};
494
495static struct notifier_block ubi32_wdt_notifier = {
496    .notifier_call = ubi32_wdt_notify_sys,
497};
498
499/*
500 * ubi32_wdt_probe()
501 * Probe/register the watchdog module
502 *
503 * Registers the misc device and notifier handler. Actual device
504 * initialization is handled by ubi32_wdt_open().
505 */
506static int __devinit ubi32_wdt_probe(struct platform_device *pdev)
507{
508    int ret;
509
510    ret = register_reboot_notifier(&ubi32_wdt_notifier);
511    if (ret) {
512        printk(KERN_ERR PFX
513            "cannot register reboot notifier (err=%d)\n", ret);
514        return ret;
515    }
516
517    ret = misc_register(&ubi32_wdt_miscdev);
518    if (ret) {
519        printk(KERN_ERR PFX
520            "cannot register miscdev on minor=%d (err=%d)\n",
521                WATCHDOG_MINOR, ret);
522        unregister_reboot_notifier(&ubi32_wdt_notifier);
523        return ret;
524    }
525
526    printk(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
527           timeout, nowayout);
528
529    return 0;
530}
531
532/*
533 * ubi32_wdt_remove()
534 * Uninstall the module
535 *
536 * Unregisters the misc device and notifier handler. Actual device
537 * deinitialization is handled by ubi32_wdt_close().
538 */
539static int __devexit ubi32_wdt_remove(struct platform_device *pdev)
540{
541    misc_deregister(&ubi32_wdt_miscdev);
542    unregister_reboot_notifier(&ubi32_wdt_notifier);
543    return 0;
544}
545
546static struct platform_device *ubi32_wdt_device;
547
548static struct platform_driver ubi32_wdt_driver = {
549    .probe = ubi32_wdt_probe,
550    .remove = __devexit_p(ubi32_wdt_remove),
551    .suspend = ubi32_wdt_suspend,
552    .resume = ubi32_wdt_resume,
553    .driver = {
554        .name = WATCHDOG_NAME,
555        .owner = THIS_MODULE,
556    },
557};
558
559/*
560 * ubi32_wdt_init()
561 * Initialize the watchdog.
562 *
563 * Checks the module params and registers the platform device & driver.
564 * Real work is in the platform probe function.
565 */
566static int __init ubi32_wdt_init(void)
567{
568    unsigned long flags;
569    int ret;
570
571    /*
572     * Check that the timeout value is within range
573     */
574    spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
575    ret = ubi32_wdt_set_timeout(timeout);
576    spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
577    if (ret) {
578        return ret;
579    }
580
581    /*
582     * Since this is an on-chip device and needs no board-specific
583     * resources, we'll handle all the platform device stuff here.
584     */
585    ret = platform_driver_register(&ubi32_wdt_driver);
586    if (ret) {
587        printk(KERN_ERR PFX "unable to register driver\n");
588        return ret;
589    }
590
591    ubi32_wdt_device = platform_device_register_simple(WATCHDOG_NAME, -1, NULL, 0);
592    if (IS_ERR(ubi32_wdt_device)) {
593        printk(KERN_ERR PFX "unable to register device\n");
594        platform_driver_unregister(&ubi32_wdt_driver);
595        return PTR_ERR(ubi32_wdt_device);
596    }
597
598    return 0;
599}
600
601/*
602 * ubi32_wdt_exit()
603 * Deinitialize module
604 *
605 * Back out the platform device & driver steps. Real work is in the
606 * platform remove function.
607 */
608static void __exit ubi32_wdt_exit(void)
609{
610    platform_device_unregister(ubi32_wdt_device);
611    platform_driver_unregister(&ubi32_wdt_driver);
612}
613
614module_init(ubi32_wdt_init);
615module_exit(ubi32_wdt_exit);
616
617MODULE_AUTHOR("Sol Kavy<sol@ubicom.com>");
618MODULE_DESCRIPTION("Ubicom32 Watchdog Device Driver");
619MODULE_LICENSE("GPL");
620MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
621
622module_param(timeout, uint, 0);
623MODULE_PARM_DESC(timeout,
624    "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
625        __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
626
627module_param(nowayout, int, 0);
628MODULE_PARM_DESC(nowayout,
629    "Watchdog cannot be stopped once started (default="
630        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
631

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