source: src/linux/universal/linux-4.9/drivers/watchdog/mpcore_wdt.c @ 31872

Last change on this file since 31872 was 31872, checked in by brainslayer, 2 months ago

change mpcore watchdog driver for laguna

File size: 10.3 KB
Line 
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
23#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24
25#include <linux/module.h>
26#include <linux/moduleparam.h>
27#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>
34#include <linux/platform_device.h>
35#include <linux/uaccess.h>
36#include <linux/slab.h>
37#include <linux/io.h>
38
39#include <asm/smp_twd.h>
40
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
50static struct platform_device *mpcore_wdt_pdev;
51static DEFINE_SPINLOCK(wdt_lock);
52
53#define TIMER_MARGIN    60
54static int mpcore_margin = TIMER_MARGIN;
55module_param(mpcore_margin, int, 0);
56MODULE_PARM_DESC(mpcore_margin,
57        "MPcore timer margin in seconds. (0 < mpcore_margin < 65536, default="
58                                __MODULE_STRING(TIMER_MARGIN) ")");
59
60static bool nowayout = WATCHDOG_NOWAYOUT;
61module_param(nowayout, bool, 0);
62MODULE_PARM_DESC(nowayout,
63        "Watchdog cannot be stopped once started (default="
64                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
65
66#define ONLY_TESTING    0
67static int mpcore_noboot = ONLY_TESTING;
68module_param(mpcore_noboot, int, 0);
69MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, "
70        "set to 1 to ignore reboots, 0 to reboot (default="
71                                        __MODULE_STRING(ONLY_TESTING) ")");
72
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 */
77static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
78{
79        struct mpcore_wdt *wdt = arg;
80
81        /* Check it really was our interrupt */
82        if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
83                dev_crit(wdt->dev, "Triggered - Reboot ignored\n");
84                /* Clear the interrupt on the watchdog */
85                writel(1, wdt->base + TWD_WDOG_INTSTAT);
86                return IRQ_HANDLED;
87        }
88        return IRQ_NONE;
89}
90
91/*
92 *      mpcore_wdt_keepalive - reload the timer
93 *
94 *      Note that the spec says a DIFFERENT value must be written to the reload
95 *      register each time.  The "perturb" variable deals with this by adding 1
96 *      to the count every other time the function is called.
97 */
98static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
99{
100        unsigned long count;
101
102        spin_lock(&wdt_lock);
103        /* Assume prescale is set to 256 */
104        count =  __raw_readl(wdt->base + TWD_WDOG_COUNTER);
105        count = (0xFFFFFFFFU - count) * (HZ / 5);
106        count = (count / 256) * mpcore_margin;
107
108        /* Reload the counter */
109        writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
110        wdt->perturb = wdt->perturb ? 0 : 1;
111        spin_unlock(&wdt_lock);
112}
113
114static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
115{
116        spin_lock(&wdt_lock);
117        writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
118        writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
119        writel(0x0, wdt->base + TWD_WDOG_CONTROL);
120        spin_unlock(&wdt_lock);
121}
122
123static void mpcore_wdt_start(struct mpcore_wdt *wdt)
124{
125        dev_info(wdt->dev, "enabling watchdog\n");
126
127        /* This loads the count register but does NOT start the count yet */
128        mpcore_wdt_keepalive(wdt);
129
130        if (mpcore_noboot) {
131                /* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
132                writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
133        } else {
134                /* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
135                writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
136        }
137}
138
139static int mpcore_wdt_set_heartbeat(int t)
140{
141        if (t < 0x0001 || t > 0xFFFF)
142                return -EINVAL;
143
144        mpcore_margin = t;
145        return 0;
146}
147
148/*
149 *      /dev/watchdog handling
150 */
151static int mpcore_wdt_open(struct inode *inode, struct file *file)
152{
153        struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_pdev);
154
155        if (test_and_set_bit(0, &wdt->timer_alive))
156                return -EBUSY;
157
158        if (nowayout)
159                __module_get(THIS_MODULE);
160
161        file->private_data = wdt;
162
163        /*
164         *      Activate timer
165         */
166        mpcore_wdt_start(wdt);
167
168        return nonseekable_open(inode, file);
169}
170
171static int mpcore_wdt_release(struct inode *inode, struct file *file)
172{
173        struct mpcore_wdt *wdt = file->private_data;
174
175        /*
176         *      Shut off the timer.
177         *      Lock it in if it's a module and we set nowayout
178         */
179        if (wdt->expect_close == 42)
180                mpcore_wdt_stop(wdt);
181        else {
182                dev_crit(wdt->dev,
183                         "unexpected close, not stopping watchdog!\n");
184                mpcore_wdt_keepalive(wdt);
185        }
186        clear_bit(0, &wdt->timer_alive);
187        wdt->expect_close = 0;
188        return 0;
189}
190
191static ssize_t mpcore_wdt_write(struct file *file, const char *data,
192                                                size_t len, loff_t *ppos)
193{
194        struct mpcore_wdt *wdt = file->private_data;
195
196        /*
197         *      Refresh the timer.
198         */
199        if (len) {
200                if (!nowayout) {
201                        size_t i;
202
203                        /* In case it was set long ago */
204                        wdt->expect_close = 0;
205
206                        for (i = 0; i != len; i++) {
207                                char c;
208
209                                if (get_user(c, data + i))
210                                        return -EFAULT;
211                                if (c == 'V')
212                                        wdt->expect_close = 42;
213                        }
214                }
215                mpcore_wdt_keepalive(wdt);
216        }
217        return len;
218}
219
220static const struct watchdog_info ident = {
221        .options                = WDIOF_SETTIMEOUT |
222                                  WDIOF_KEEPALIVEPING |
223                                  WDIOF_MAGICCLOSE,
224        .identity               = "MPcore Watchdog",
225};
226
227static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
228                                                        unsigned long arg)
229{
230        struct mpcore_wdt *wdt = file->private_data;
231        int ret;
232        union {
233                struct watchdog_info ident;
234                int i;
235        } uarg;
236
237        if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
238                return -ENOTTY;
239
240        if (_IOC_DIR(cmd) & _IOC_WRITE) {
241                ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
242                if (ret)
243                        return -EFAULT;
244        }
245
246        switch (cmd) {
247        case WDIOC_GETSUPPORT:
248                uarg.ident = ident;
249                ret = 0;
250                break;
251
252        case WDIOC_GETSTATUS:
253        case WDIOC_GETBOOTSTATUS:
254                uarg.i = 0;
255                ret = 0;
256                break;
257
258        case WDIOC_SETOPTIONS:
259                ret = -EINVAL;
260                if (uarg.i & WDIOS_DISABLECARD) {
261                        mpcore_wdt_stop(wdt);
262                        ret = 0;
263                }
264                if (uarg.i & WDIOS_ENABLECARD) {
265                        mpcore_wdt_start(wdt);
266                        ret = 0;
267                }
268                break;
269
270        case WDIOC_KEEPALIVE:
271                mpcore_wdt_keepalive(wdt);
272                ret = 0;
273                break;
274
275        case WDIOC_SETTIMEOUT:
276                ret = mpcore_wdt_set_heartbeat(uarg.i);
277                if (ret)
278                        break;
279
280                mpcore_wdt_keepalive(wdt);
281                /* Fall */
282        case WDIOC_GETTIMEOUT:
283                uarg.i = mpcore_margin;
284                ret = 0;
285                break;
286
287        default:
288                return -ENOTTY;
289        }
290
291        if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
292                ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
293                if (ret)
294                        ret = -EFAULT;
295        }
296        return ret;
297}
298
299/*
300 *      System shutdown handler.  Turn off the watchdog if we're
301 *      restarting or halting the system.
302 */
303static void mpcore_wdt_shutdown(struct platform_device *pdev)
304{
305        struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
306
307        if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
308                mpcore_wdt_stop(wdt);
309}
310
311/*
312 *      Kernel Interfaces
313 */
314static const struct file_operations mpcore_wdt_fops = {
315        .owner          = THIS_MODULE,
316        .llseek         = no_llseek,
317        .write          = mpcore_wdt_write,
318        .unlocked_ioctl = mpcore_wdt_ioctl,
319        .open           = mpcore_wdt_open,
320        .release        = mpcore_wdt_release,
321};
322
323static struct miscdevice mpcore_wdt_miscdev = {
324        .minor          = WATCHDOG_MINOR,
325        .name           = "watchdog",
326        .fops           = &mpcore_wdt_fops,
327};
328
329static int mpcore_wdt_probe(struct platform_device *pdev)
330{
331        struct mpcore_wdt *wdt;
332        struct resource *res;
333        int ret;
334
335        /* We only accept one device, and it must have an id of -1 */
336        if (pdev->id != -1)
337                return -ENODEV;
338
339        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
340        if (!res)
341                return -ENODEV;
342
343        wdt = devm_kzalloc(&pdev->dev, sizeof(struct mpcore_wdt), GFP_KERNEL);
344        if (!wdt)
345                return -ENOMEM;
346
347        wdt->dev = &pdev->dev;
348        wdt->irq = platform_get_irq(pdev, 0);
349        if (wdt->irq >= 0) {
350                ret = devm_request_irq(wdt->dev, wdt->irq, mpcore_wdt_fire, 0,
351                                "mpcore_wdt", wdt);
352                if (ret) {
353                        dev_err(wdt->dev,
354                                "cannot register IRQ%d for watchdog\n",
355                                wdt->irq);
356                        return ret;
357                }
358        }
359
360        wdt->base = devm_ioremap(wdt->dev, res->start, resource_size(res));
361        if (!wdt->base)
362                return -ENOMEM;
363
364        mpcore_wdt_miscdev.parent = &pdev->dev;
365        ret = misc_register(&mpcore_wdt_miscdev);
366        if (ret) {
367                dev_err(wdt->dev,
368                        "cannot register miscdev on minor=%d (err=%d)\n",
369                        WATCHDOG_MINOR, ret);
370                return ret;
371        }
372
373        mpcore_wdt_stop(wdt);
374        platform_set_drvdata(pdev, wdt);
375        mpcore_wdt_pdev = pdev;
376
377        return 0;
378}
379
380static int mpcore_wdt_remove(struct platform_device *pdev)
381{
382        platform_set_drvdata(pdev, NULL);
383
384        misc_deregister(&mpcore_wdt_miscdev);
385
386        mpcore_wdt_pdev = NULL;
387
388        return 0;
389}
390
391#ifdef CONFIG_PM
392static int mpcore_wdt_suspend(struct platform_device *pdev, pm_message_t msg)
393{
394        struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
395        mpcore_wdt_stop(wdt);           /* Turn the WDT off */
396        return 0;
397}
398
399static int mpcore_wdt_resume(struct platform_device *pdev)
400{
401        struct mpcore_wdt *wdt = platform_get_drvdata(pdev);
402        /* re-activate timer */
403        if (test_bit(0, &wdt->timer_alive))
404                mpcore_wdt_start(wdt);
405        return 0;
406}
407#else
408#define mpcore_wdt_suspend      NULL
409#define mpcore_wdt_resume       NULL
410#endif
411
412/* work with hotplug and coldplug */
413MODULE_ALIAS("platform:mpcore_wdt");
414
415static struct platform_driver mpcore_wdt_driver = {
416        .probe          = mpcore_wdt_probe,
417        .remove         = mpcore_wdt_remove,
418        .suspend        = mpcore_wdt_suspend,
419        .resume         = mpcore_wdt_resume,
420        .shutdown       = mpcore_wdt_shutdown,
421        .driver         = {
422                .owner  = THIS_MODULE,
423                .name   = "mpcore_wdt",
424        },
425};
426
427static int __init mpcore_wdt_init(void)
428{
429        /*
430         * Check that the margin value is within it's range;
431         * if not reset to the default
432         */
433        if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
434                mpcore_wdt_set_heartbeat(TIMER_MARGIN);
435                pr_info("mpcore_margin value must be 0 < mpcore_margin < 65536, using %d\n",
436                        TIMER_MARGIN);
437        }
438
439        pr_info("MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n",
440                mpcore_noboot, mpcore_margin, nowayout);
441
442        return platform_driver_register(&mpcore_wdt_driver);
443}
444
445static void __exit mpcore_wdt_exit(void)
446{
447        platform_driver_unregister(&mpcore_wdt_driver);
448}
449
450module_init(mpcore_wdt_init);
451module_exit(mpcore_wdt_exit);
452
453MODULE_AUTHOR("ARM Limited");
454MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
455MODULE_LICENSE("GPL");
456MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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