a1d7856ea6e0adaccfd974b5aaddd52225fc2e6a
[linux-drm-fsl-dcu.git] / 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 #include <linux/module.h>
32 #include <linux/moduleparam.h>
33 #include <linux/types.h>
34 #include <linux/miscdevice.h>
35 #include <linux/watchdog.h>
36 #include <linux/fs.h>
37 #include <linux/ioport.h>
38 #include <linux/platform_device.h>
39 #include <linux/init.h>
40 #include <linux/io.h>
41 #include <linux/uaccess.h>
42
43 #include <asm/system.h>
44
45 #define DRV_NAME "advantechwdt"
46 #define PFX DRV_NAME ": "
47 #define WATCHDOG_NAME "Advantech WDT"
48 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
49
50 /* the watchdog platform device */
51 static struct platform_device *advwdt_platform_device;
52 static unsigned long advwdt_is_open;
53 static 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
66 static int wdt_stop = 0x443;
67 module_param(wdt_stop, int, 0);
68 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
69
70 static int wdt_start = 0x443;
71 module_param(wdt_start, int, 0);
72 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
73
74 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
75 module_param(timeout, int, 0);
76 MODULE_PARM_DESC(timeout,
77         "Watchdog timeout in seconds. 1<= timeout <=63, default="
78                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
79
80 static int nowayout = WATCHDOG_NOWAYOUT;
81 module_param(nowayout, int, 0);
82 MODULE_PARM_DESC(nowayout,
83         "Watchdog cannot be stopped once started (default="
84                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
85
86 /*
87  *      Watchdog Operations
88  */
89
90 static void advwdt_ping(void)
91 {
92         /* Write a watchdog value */
93         outb_p(timeout, wdt_start);
94 }
95
96 static void advwdt_disable(void)
97 {
98         inb_p(wdt_stop);
99 }
100
101 static 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
113 static 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
135 static 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 struct watchdog_info ident = {
141                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
142                 .firmware_version = 1,
143                 .identity = WATCHDOG_NAME,
144         };
145
146         switch (cmd) {
147         case WDIOC_GETSUPPORT:
148                 if (copy_to_user(argp, &ident, sizeof(ident)))
149                         return -EFAULT;
150                 break;
151
152         case WDIOC_GETSTATUS:
153         case WDIOC_GETBOOTSTATUS:
154                 return put_user(0, p);
155
156         case WDIOC_SETOPTIONS:
157         {
158                 int options, retval = -EINVAL;
159
160                 if (get_user(options, p))
161                         return -EFAULT;
162                 if (options & WDIOS_DISABLECARD) {
163                         advwdt_disable();
164                         retval = 0;
165                 }
166                 if (options & WDIOS_ENABLECARD) {
167                         advwdt_ping();
168                         retval = 0;
169                 }
170                 return retval;
171         }
172         case WDIOC_KEEPALIVE:
173                 advwdt_ping();
174                 break;
175
176         case WDIOC_SETTIMEOUT:
177                 if (get_user(new_timeout, p))
178                         return -EFAULT;
179                 if (advwdt_set_heartbeat(new_timeout))
180                         return -EINVAL;
181                 advwdt_ping();
182                 /* Fall */
183         case WDIOC_GETTIMEOUT:
184                 return put_user(timeout, p);
185         default:
186                 return -ENOTTY;
187         }
188         return 0;
189 }
190
191 static int advwdt_open(struct inode *inode, struct file *file)
192 {
193         if (test_and_set_bit(0, &advwdt_is_open))
194                 return -EBUSY;
195         /*
196          *      Activate
197          */
198
199         advwdt_ping();
200         return nonseekable_open(inode, file);
201 }
202
203 static int advwdt_close(struct inode *inode, struct file *file)
204 {
205         if (adv_expect_close == 42) {
206                 advwdt_disable();
207         } else {
208                 printk(KERN_CRIT PFX
209                                 "Unexpected close, not stopping watchdog!\n");
210                 advwdt_ping();
211         }
212         clear_bit(0, &advwdt_is_open);
213         adv_expect_close = 0;
214         return 0;
215 }
216
217 /*
218  *      Kernel Interfaces
219  */
220
221 static const struct file_operations advwdt_fops = {
222         .owner          = THIS_MODULE,
223         .llseek         = no_llseek,
224         .write          = advwdt_write,
225         .unlocked_ioctl = advwdt_ioctl,
226         .open           = advwdt_open,
227         .release        = advwdt_close,
228 };
229
230 static struct miscdevice advwdt_miscdev = {
231         .minor  = WATCHDOG_MINOR,
232         .name   = "watchdog",
233         .fops   = &advwdt_fops,
234 };
235
236 /*
237  *      Init & exit routines
238  */
239
240 static int __devinit advwdt_probe(struct platform_device *dev)
241 {
242         int ret;
243
244         if (wdt_stop != wdt_start) {
245                 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
246                         printk(KERN_ERR PFX
247                                 "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                 printk(KERN_ERR PFX
256                                 "I/O address 0x%04x already in use\n",
257                                                                 wdt_start);
258                 ret = -EIO;
259                 goto unreg_stop;
260         }
261
262         /* Check that the heartbeat value is within it's range ; if not reset to the default */
263         if (advwdt_set_heartbeat(timeout)) {
264                 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
265                 printk(KERN_INFO PFX
266                         "timeout value must be 1<=x<=63, using %d\n", timeout);
267         }
268
269         ret = misc_register(&advwdt_miscdev);
270         if (ret != 0) {
271                 printk(KERN_ERR PFX
272                         "cannot register miscdev on minor=%d (err=%d)\n",
273                                                         WATCHDOG_MINOR, ret);
274                 goto unreg_regions;
275         }
276         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
277                 timeout, nowayout);
278 out:
279         return ret;
280 unreg_regions:
281         release_region(wdt_start, 1);
282 unreg_stop:
283         if (wdt_stop != wdt_start)
284                 release_region(wdt_stop, 1);
285         goto out;
286 }
287
288 static int __devexit advwdt_remove(struct platform_device *dev)
289 {
290         misc_deregister(&advwdt_miscdev);
291         release_region(wdt_start, 1);
292         if (wdt_stop != wdt_start)
293                 release_region(wdt_stop, 1);
294
295         return 0;
296 }
297
298 static void advwdt_shutdown(struct platform_device *dev)
299 {
300         /* Turn the WDT off if we have a soft shutdown */
301         advwdt_disable();
302 }
303
304 static struct platform_driver advwdt_driver = {
305         .probe          = advwdt_probe,
306         .remove         = __devexit_p(advwdt_remove),
307         .shutdown       = advwdt_shutdown,
308         .driver         = {
309                 .owner  = THIS_MODULE,
310                 .name   = DRV_NAME,
311         },
312 };
313
314 static int __init advwdt_init(void)
315 {
316         int err;
317
318         printk(KERN_INFO
319              "WDT driver for Advantech single board computer initialising.\n");
320
321         err = platform_driver_register(&advwdt_driver);
322         if (err)
323                 return err;
324
325         advwdt_platform_device = platform_device_register_simple(DRV_NAME,
326                                                                 -1, NULL, 0);
327         if (IS_ERR(advwdt_platform_device)) {
328                 err = PTR_ERR(advwdt_platform_device);
329                 goto unreg_platform_driver;
330         }
331
332         return 0;
333
334 unreg_platform_driver:
335         platform_driver_unregister(&advwdt_driver);
336         return err;
337 }
338
339 static void __exit advwdt_exit(void)
340 {
341         platform_device_unregister(advwdt_platform_device);
342         platform_driver_unregister(&advwdt_driver);
343         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
344 }
345
346 module_init(advwdt_init);
347 module_exit(advwdt_exit);
348
349 MODULE_LICENSE("GPL");
350 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
351 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
352 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);