Root/drivers/watchdog/advantechwdt.c

1/*
2 * Advantech Single Board Computer WDT driver
3 *
4 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
5 *
6 * Based on acquirewdt.c which is based on wdt.c.
7 * Original copyright messages:
8 *
9 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
10 * All Rights Reserved.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 *
17 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
18 * warranty for any of this software. This material is provided
19 * "AS-IS" and at no charge.
20 *
21 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
22 *
23 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
24 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
25 *
26 * 16-Oct-2002 Rob Radez <rob@osinvestor.com>
27 * Clean up ioctls, clean up init + exit, add expect close support,
28 * add wdt_start and wdt_stop as parameters.
29 */
30
31#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33#include <linux/module.h>
34#include <linux/moduleparam.h>
35#include <linux/types.h>
36#include <linux/miscdevice.h>
37#include <linux/watchdog.h>
38#include <linux/fs.h>
39#include <linux/ioport.h>
40#include <linux/platform_device.h>
41#include <linux/init.h>
42#include <linux/io.h>
43#include <linux/uaccess.h>
44
45
46#define DRV_NAME "advantechwdt"
47#define WATCHDOG_NAME "Advantech WDT"
48#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
49
50/* the watchdog platform device */
51static struct platform_device *advwdt_platform_device;
52static unsigned long advwdt_is_open;
53static char adv_expect_close;
54
55/*
56 * You must set these - there is no sane way to probe for this board.
57 *
58 * To enable or restart, write the timeout value in seconds (1 to 63)
59 * to I/O port wdt_start. To disable, read I/O port wdt_stop.
60 * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
61 * check your manual (at least the PCA-6159 seems to be different -
62 * the manual says wdt_stop is 0x43, not 0x443).
63 * (0x43 is also a write-only control register for the 8254 timer!)
64 */
65
66static int wdt_stop = 0x443;
67module_param(wdt_stop, int, 0);
68MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
69
70static int wdt_start = 0x443;
71module_param(wdt_start, int, 0);
72MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
73
74static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
75module_param(timeout, int, 0);
76MODULE_PARM_DESC(timeout,
77    "Watchdog timeout in seconds. 1<= timeout <=63, default="
78        __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
79
80static bool nowayout = WATCHDOG_NOWAYOUT;
81module_param(nowayout, bool, 0);
82MODULE_PARM_DESC(nowayout,
83    "Watchdog cannot be stopped once started (default="
84        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
85
86/*
87 * Watchdog Operations
88 */
89
90static void advwdt_ping(void)
91{
92    /* Write a watchdog value */
93    outb_p(timeout, wdt_start);
94}
95
96static void advwdt_disable(void)
97{
98    inb_p(wdt_stop);
99}
100
101static int advwdt_set_heartbeat(int t)
102{
103    if (t < 1 || t > 63)
104        return -EINVAL;
105    timeout = t;
106    return 0;
107}
108
109/*
110 * /dev/watchdog handling
111 */
112
113static ssize_t advwdt_write(struct file *file, const char __user *buf,
114                        size_t count, loff_t *ppos)
115{
116    if (count) {
117        if (!nowayout) {
118            size_t i;
119
120            adv_expect_close = 0;
121
122            for (i = 0; i != count; i++) {
123                char c;
124                if (get_user(c, buf + i))
125                    return -EFAULT;
126                if (c == 'V')
127                    adv_expect_close = 42;
128            }
129        }
130        advwdt_ping();
131    }
132    return count;
133}
134
135static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
136{
137    int new_timeout;
138    void __user *argp = (void __user *)arg;
139    int __user *p = argp;
140    static const struct watchdog_info ident = {
141        .options = WDIOF_KEEPALIVEPING |
142               WDIOF_SETTIMEOUT |
143               WDIOF_MAGICCLOSE,
144        .firmware_version = 1,
145        .identity = WATCHDOG_NAME,
146    };
147
148    switch (cmd) {
149    case WDIOC_GETSUPPORT:
150        if (copy_to_user(argp, &ident, sizeof(ident)))
151            return -EFAULT;
152        break;
153
154    case WDIOC_GETSTATUS:
155    case WDIOC_GETBOOTSTATUS:
156        return put_user(0, p);
157
158    case WDIOC_SETOPTIONS:
159    {
160        int options, retval = -EINVAL;
161
162        if (get_user(options, p))
163            return -EFAULT;
164        if (options & WDIOS_DISABLECARD) {
165            advwdt_disable();
166            retval = 0;
167        }
168        if (options & WDIOS_ENABLECARD) {
169            advwdt_ping();
170            retval = 0;
171        }
172        return retval;
173    }
174    case WDIOC_KEEPALIVE:
175        advwdt_ping();
176        break;
177
178    case WDIOC_SETTIMEOUT:
179        if (get_user(new_timeout, p))
180            return -EFAULT;
181        if (advwdt_set_heartbeat(new_timeout))
182            return -EINVAL;
183        advwdt_ping();
184        /* Fall */
185    case WDIOC_GETTIMEOUT:
186        return put_user(timeout, p);
187    default:
188        return -ENOTTY;
189    }
190    return 0;
191}
192
193static int advwdt_open(struct inode *inode, struct file *file)
194{
195    if (test_and_set_bit(0, &advwdt_is_open))
196        return -EBUSY;
197    /*
198     * Activate
199     */
200
201    advwdt_ping();
202    return nonseekable_open(inode, file);
203}
204
205static int advwdt_close(struct inode *inode, struct file *file)
206{
207    if (adv_expect_close == 42) {
208        advwdt_disable();
209    } else {
210        pr_crit("Unexpected close, not stopping watchdog!\n");
211        advwdt_ping();
212    }
213    clear_bit(0, &advwdt_is_open);
214    adv_expect_close = 0;
215    return 0;
216}
217
218/*
219 * Kernel Interfaces
220 */
221
222static const struct file_operations advwdt_fops = {
223    .owner = THIS_MODULE,
224    .llseek = no_llseek,
225    .write = advwdt_write,
226    .unlocked_ioctl = advwdt_ioctl,
227    .open = advwdt_open,
228    .release = advwdt_close,
229};
230
231static struct miscdevice advwdt_miscdev = {
232    .minor = WATCHDOG_MINOR,
233    .name = "watchdog",
234    .fops = &advwdt_fops,
235};
236
237/*
238 * Init & exit routines
239 */
240
241static int __devinit advwdt_probe(struct platform_device *dev)
242{
243    int ret;
244
245    if (wdt_stop != wdt_start) {
246        if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
247            pr_err("I/O address 0x%04x already in use\n",
248                   wdt_stop);
249            ret = -EIO;
250            goto out;
251        }
252    }
253
254    if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
255        pr_err("I/O address 0x%04x already in use\n", wdt_start);
256        ret = -EIO;
257        goto unreg_stop;
258    }
259
260    /* Check that the heartbeat value is within it's range ;
261     * if not reset to the default */
262    if (advwdt_set_heartbeat(timeout)) {
263        advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
264        pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
265    }
266
267    ret = misc_register(&advwdt_miscdev);
268    if (ret != 0) {
269        pr_err("cannot register miscdev on minor=%d (err=%d)\n",
270               WATCHDOG_MINOR, ret);
271        goto unreg_regions;
272    }
273    pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
274        timeout, nowayout);
275out:
276    return ret;
277unreg_regions:
278    release_region(wdt_start, 1);
279unreg_stop:
280    if (wdt_stop != wdt_start)
281        release_region(wdt_stop, 1);
282    goto out;
283}
284
285static int __devexit advwdt_remove(struct platform_device *dev)
286{
287    misc_deregister(&advwdt_miscdev);
288    release_region(wdt_start, 1);
289    if (wdt_stop != wdt_start)
290        release_region(wdt_stop, 1);
291
292    return 0;
293}
294
295static void advwdt_shutdown(struct platform_device *dev)
296{
297    /* Turn the WDT off if we have a soft shutdown */
298    advwdt_disable();
299}
300
301static struct platform_driver advwdt_driver = {
302    .probe = advwdt_probe,
303    .remove = __devexit_p(advwdt_remove),
304    .shutdown = advwdt_shutdown,
305    .driver = {
306        .owner = THIS_MODULE,
307        .name = DRV_NAME,
308    },
309};
310
311static int __init advwdt_init(void)
312{
313    int err;
314
315    pr_info("WDT driver for Advantech single board computer initialising\n");
316
317    err = platform_driver_register(&advwdt_driver);
318    if (err)
319        return err;
320
321    advwdt_platform_device = platform_device_register_simple(DRV_NAME,
322                                -1, NULL, 0);
323    if (IS_ERR(advwdt_platform_device)) {
324        err = PTR_ERR(advwdt_platform_device);
325        goto unreg_platform_driver;
326    }
327
328    return 0;
329
330unreg_platform_driver:
331    platform_driver_unregister(&advwdt_driver);
332    return err;
333}
334
335static void __exit advwdt_exit(void)
336{
337    platform_device_unregister(advwdt_platform_device);
338    platform_driver_unregister(&advwdt_driver);
339    pr_info("Watchdog Module Unloaded\n");
340}
341
342module_init(advwdt_init);
343module_exit(advwdt_exit);
344
345MODULE_LICENSE("GPL");
346MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
347MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
348MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
349

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