virtio-mem: simplify high-level unplug handling in Sub Block Mode
[linux-2.6-microblaze.git] / drivers / watchdog / advantechwdt.c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *      Advantech Single Board Computer WDT driver
4  *
5  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
6  *
7  *      Based on acquirewdt.c which is based on wdt.c.
8  *      Original copyright messages:
9  *
10  *      (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
11  *                                              All Rights Reserved.
12  *
13  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
14  *      warranty for any of this software. This material is provided
15  *      "AS-IS" and at no charge.
16  *
17  *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
18  *
19  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
20  *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
21  *
22  *      16-Oct-2002 Rob Radez <rob@osinvestor.com>
23  *          Clean up ioctls, clean up init + exit, add expect close support,
24  *          add wdt_start and wdt_stop as parameters.
25  */
26
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/types.h>
32 #include <linux/miscdevice.h>
33 #include <linux/watchdog.h>
34 #include <linux/fs.h>
35 #include <linux/ioport.h>
36 #include <linux/platform_device.h>
37 #include <linux/init.h>
38 #include <linux/io.h>
39 #include <linux/uaccess.h>
40
41
42 #define DRV_NAME "advantechwdt"
43 #define WATCHDOG_NAME "Advantech WDT"
44 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
45
46 /* the watchdog platform device */
47 static struct platform_device *advwdt_platform_device;
48 static unsigned long advwdt_is_open;
49 static char adv_expect_close;
50
51 /*
52  *      You must set these - there is no sane way to probe for this board.
53  *
54  *      To enable or restart, write the timeout value in seconds (1 to 63)
55  *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.
56  *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
57  *      check your manual (at least the PCA-6159 seems to be different -
58  *      the manual says wdt_stop is 0x43, not 0x443).
59  *      (0x43 is also a write-only control register for the 8254 timer!)
60  */
61
62 static int wdt_stop = 0x443;
63 module_param(wdt_stop, int, 0);
64 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
65
66 static int wdt_start = 0x443;
67 module_param(wdt_start, int, 0);
68 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
69
70 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
71 module_param(timeout, int, 0);
72 MODULE_PARM_DESC(timeout,
73         "Watchdog timeout in seconds. 1<= timeout <=63, default="
74                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
75
76 static bool nowayout = WATCHDOG_NOWAYOUT;
77 module_param(nowayout, bool, 0);
78 MODULE_PARM_DESC(nowayout,
79         "Watchdog cannot be stopped once started (default="
80                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
81
82 /*
83  *      Watchdog Operations
84  */
85
86 static void advwdt_ping(void)
87 {
88         /* Write a watchdog value */
89         outb_p(timeout, wdt_start);
90 }
91
92 static void advwdt_disable(void)
93 {
94         inb_p(wdt_stop);
95 }
96
97 static int advwdt_set_heartbeat(int t)
98 {
99         if (t < 1 || t > 63)
100                 return -EINVAL;
101         timeout = t;
102         return 0;
103 }
104
105 /*
106  *      /dev/watchdog handling
107  */
108
109 static ssize_t advwdt_write(struct file *file, const char __user *buf,
110                                                 size_t count, loff_t *ppos)
111 {
112         if (count) {
113                 if (!nowayout) {
114                         size_t i;
115
116                         adv_expect_close = 0;
117
118                         for (i = 0; i != count; i++) {
119                                 char c;
120                                 if (get_user(c, buf + i))
121                                         return -EFAULT;
122                                 if (c == 'V')
123                                         adv_expect_close = 42;
124                         }
125                 }
126                 advwdt_ping();
127         }
128         return count;
129 }
130
131 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
132 {
133         int new_timeout;
134         void __user *argp = (void __user *)arg;
135         int __user *p = argp;
136         static const struct watchdog_info ident = {
137                 .options = WDIOF_KEEPALIVEPING |
138                            WDIOF_SETTIMEOUT |
139                            WDIOF_MAGICCLOSE,
140                 .firmware_version = 1,
141                 .identity = WATCHDOG_NAME,
142         };
143
144         switch (cmd) {
145         case WDIOC_GETSUPPORT:
146                 if (copy_to_user(argp, &ident, sizeof(ident)))
147                         return -EFAULT;
148                 break;
149
150         case WDIOC_GETSTATUS:
151         case WDIOC_GETBOOTSTATUS:
152                 return put_user(0, p);
153
154         case WDIOC_SETOPTIONS:
155         {
156                 int options, retval = -EINVAL;
157
158                 if (get_user(options, p))
159                         return -EFAULT;
160                 if (options & WDIOS_DISABLECARD) {
161                         advwdt_disable();
162                         retval = 0;
163                 }
164                 if (options & WDIOS_ENABLECARD) {
165                         advwdt_ping();
166                         retval = 0;
167                 }
168                 return retval;
169         }
170         case WDIOC_KEEPALIVE:
171                 advwdt_ping();
172                 break;
173
174         case WDIOC_SETTIMEOUT:
175                 if (get_user(new_timeout, p))
176                         return -EFAULT;
177                 if (advwdt_set_heartbeat(new_timeout))
178                         return -EINVAL;
179                 advwdt_ping();
180                 fallthrough;
181         case WDIOC_GETTIMEOUT:
182                 return put_user(timeout, p);
183         default:
184                 return -ENOTTY;
185         }
186         return 0;
187 }
188
189 static int advwdt_open(struct inode *inode, struct file *file)
190 {
191         if (test_and_set_bit(0, &advwdt_is_open))
192                 return -EBUSY;
193         /*
194          *      Activate
195          */
196
197         advwdt_ping();
198         return stream_open(inode, file);
199 }
200
201 static int advwdt_close(struct inode *inode, struct file *file)
202 {
203         if (adv_expect_close == 42) {
204                 advwdt_disable();
205         } else {
206                 pr_crit("Unexpected close, not stopping watchdog!\n");
207                 advwdt_ping();
208         }
209         clear_bit(0, &advwdt_is_open);
210         adv_expect_close = 0;
211         return 0;
212 }
213
214 /*
215  *      Kernel Interfaces
216  */
217
218 static const struct file_operations advwdt_fops = {
219         .owner          = THIS_MODULE,
220         .llseek         = no_llseek,
221         .write          = advwdt_write,
222         .unlocked_ioctl = advwdt_ioctl,
223         .compat_ioctl   = compat_ptr_ioctl,
224         .open           = advwdt_open,
225         .release        = advwdt_close,
226 };
227
228 static struct miscdevice advwdt_miscdev = {
229         .minor  = WATCHDOG_MINOR,
230         .name   = "watchdog",
231         .fops   = &advwdt_fops,
232 };
233
234 /*
235  *      Init & exit routines
236  */
237
238 static int __init advwdt_probe(struct platform_device *dev)
239 {
240         int ret;
241
242         if (wdt_stop != wdt_start) {
243                 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
244                         pr_err("I/O address 0x%04x already in use\n",
245                                wdt_stop);
246                         ret = -EIO;
247                         goto out;
248                 }
249         }
250
251         if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
252                 pr_err("I/O address 0x%04x already in use\n", wdt_start);
253                 ret = -EIO;
254                 goto unreg_stop;
255         }
256
257         /* Check that the heartbeat value is within it's range ;
258          * if not reset to the default */
259         if (advwdt_set_heartbeat(timeout)) {
260                 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
261                 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
262         }
263
264         ret = misc_register(&advwdt_miscdev);
265         if (ret != 0) {
266                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
267                        WATCHDOG_MINOR, ret);
268                 goto unreg_regions;
269         }
270         pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
271                 timeout, nowayout);
272 out:
273         return ret;
274 unreg_regions:
275         release_region(wdt_start, 1);
276 unreg_stop:
277         if (wdt_stop != wdt_start)
278                 release_region(wdt_stop, 1);
279         goto out;
280 }
281
282 static int advwdt_remove(struct platform_device *dev)
283 {
284         misc_deregister(&advwdt_miscdev);
285         release_region(wdt_start, 1);
286         if (wdt_stop != wdt_start)
287                 release_region(wdt_stop, 1);
288
289         return 0;
290 }
291
292 static void advwdt_shutdown(struct platform_device *dev)
293 {
294         /* Turn the WDT off if we have a soft shutdown */
295         advwdt_disable();
296 }
297
298 static struct platform_driver advwdt_driver = {
299         .remove         = advwdt_remove,
300         .shutdown       = advwdt_shutdown,
301         .driver         = {
302                 .name   = DRV_NAME,
303         },
304 };
305
306 static int __init advwdt_init(void)
307 {
308         int err;
309
310         pr_info("WDT driver for Advantech single board computer initialising\n");
311
312         advwdt_platform_device = platform_device_register_simple(DRV_NAME,
313                                                                 -1, NULL, 0);
314         if (IS_ERR(advwdt_platform_device))
315                 return PTR_ERR(advwdt_platform_device);
316
317         err = platform_driver_probe(&advwdt_driver, advwdt_probe);
318         if (err)
319                 goto unreg_platform_device;
320
321         return 0;
322
323 unreg_platform_device:
324         platform_device_unregister(advwdt_platform_device);
325         return err;
326 }
327
328 static void __exit advwdt_exit(void)
329 {
330         platform_device_unregister(advwdt_platform_device);
331         platform_driver_unregister(&advwdt_driver);
332         pr_info("Watchdog Module Unloaded\n");
333 }
334
335 module_init(advwdt_init);
336 module_exit(advwdt_exit);
337
338 MODULE_LICENSE("GPL");
339 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
340 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");