1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Eurotech CPU-1220/1410/1420 on board WDT driver
4 *
5 * (c) Copyright 2001 Ascensit <support@ascensit.com>
6 * (c) Copyright 2001 Rodolfo Giometti <giometti@ascensit.com>
7 * (c) Copyright 2002 Rob Radez <rob@osinvestor.com>
8 *
9 * Based on wdt.c.
10 * Original copyright messages:
11 *
12 * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
13 * All Rights Reserved.
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/* Changelog:
23 *
24 * 2001 - Rodolfo Giometti
25 * Initial release
26 *
27 * 2002/04/25 - Rob Radez
28 * clean up #includes
29 * clean up locking
30 * make __setup param unique
31 * proper options in watchdog_info
32 * add WDIOC_GETSTATUS and WDIOC_SETOPTIONS ioctls
33 * add expect_close support
34 *
35 * 2002.05.30 - Joel Becker <joel.becker@oracle.com>
36 * Added Matt Domsch's nowayout module option.
37 */
38
39/*
40 * The eurotech CPU-1220/1410/1420's watchdog is a part
41 * of the on-board SUPER I/O device SMSC FDC 37B782.
42 */
43
44#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
45
46#include <linux/interrupt.h>
47#include <linux/module.h>
48#include <linux/moduleparam.h>
49#include <linux/types.h>
50#include <linux/miscdevice.h>
51#include <linux/watchdog.h>
52#include <linux/fs.h>
53#include <linux/ioport.h>
54#include <linux/notifier.h>
55#include <linux/reboot.h>
56#include <linux/init.h>
57#include <linux/io.h>
58#include <linux/uaccess.h>
59
60
61static unsigned long eurwdt_is_open;
62static int eurwdt_timeout;
63static char eur_expect_close;
64static DEFINE_SPINLOCK(eurwdt_lock);
65
66/*
67 * You must set these - there is no sane way to probe for this board.
68 */
69
70static int io = 0x3f0;
71static int irq = 10;
72static char *ev = "int";
73
74#define WDT_TIMEOUT 60 /* 1 minute */
75
76static bool nowayout = WATCHDOG_NOWAYOUT;
77module_param(nowayout, bool, 0);
78MODULE_PARM_DESC(nowayout,
79 "Watchdog cannot be stopped once started (default="
80 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
81
82/*
83 * Some symbolic names
84 */
85
86#define WDT_CTRL_REG 0x30
87#define WDT_OUTPIN_CFG 0xe2
88#define WDT_EVENT_INT 0x00
89#define WDT_EVENT_REBOOT 0x08
90#define WDT_UNIT_SEL 0xf1
91#define WDT_UNIT_SECS 0x80
92#define WDT_TIMEOUT_VAL 0xf2
93#define WDT_TIMER_CFG 0xf3
94
95
96module_param_hw(io, int, ioport, 0);
97MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
98module_param_hw(irq, int, irq, 0);
99MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
100module_param(ev, charp, 0);
101MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
102
103
104/*
105 * Programming support
106 */
107
108static inline void eurwdt_write_reg(u8 index, u8 data)
109{
110 outb(value: index, port: io);
111 outb(value: data, port: io+1);
112}
113
114static inline void eurwdt_lock_chip(void)
115{
116 outb(value: 0xaa, port: io);
117}
118
119static inline void eurwdt_unlock_chip(void)
120{
121 outb(value: 0x55, port: io);
122 eurwdt_write_reg(index: 0x07, data: 0x08); /* set the logical device */
123}
124
125static inline void eurwdt_set_timeout(int timeout)
126{
127 eurwdt_write_reg(WDT_TIMEOUT_VAL, data: (u8) timeout);
128}
129
130static inline void eurwdt_disable_timer(void)
131{
132 eurwdt_set_timeout(timeout: 0);
133}
134
135static void eurwdt_activate_timer(void)
136{
137 eurwdt_disable_timer();
138 eurwdt_write_reg(WDT_CTRL_REG, data: 0x01); /* activate the WDT */
139 eurwdt_write_reg(WDT_OUTPIN_CFG,
140 data: !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT);
141
142 /* Setting interrupt line */
143 if (irq == 2 || irq > 15 || irq < 0) {
144 pr_err("invalid irq number\n");
145 irq = 0; /* if invalid we disable interrupt */
146 }
147 if (irq == 0)
148 pr_info("interrupt disabled\n");
149
150 eurwdt_write_reg(WDT_TIMER_CFG, data: irq << 4);
151
152 eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS); /* we use seconds */
153 eurwdt_set_timeout(timeout: 0); /* the default timeout */
154}
155
156
157/*
158 * Kernel methods.
159 */
160
161static irqreturn_t eurwdt_interrupt(int irq, void *dev_id)
162{
163 pr_crit("timeout WDT timeout\n");
164
165#ifdef ONLY_TESTING
166 pr_crit("Would Reboot\n");
167#else
168 pr_crit("Initiating system reboot\n");
169 emergency_restart();
170#endif
171 return IRQ_HANDLED;
172}
173
174
175/**
176 * eurwdt_ping:
177 *
178 * Reload counter one with the watchdog timeout.
179 */
180
181static void eurwdt_ping(void)
182{
183 /* Write the watchdog default value */
184 eurwdt_set_timeout(timeout: eurwdt_timeout);
185}
186
187/**
188 * eurwdt_write:
189 * @file: file handle to the watchdog
190 * @buf: buffer to write (unused as data does not matter here
191 * @count: count of bytes
192 * @ppos: pointer to the position to write. No seeks allowed
193 *
194 * A write to a watchdog device is defined as a keepalive signal. Any
195 * write of data will do, as we don't define content meaning.
196 */
197
198static ssize_t eurwdt_write(struct file *file, const char __user *buf,
199size_t count, loff_t *ppos)
200{
201 if (count) {
202 if (!nowayout) {
203 size_t i;
204
205 eur_expect_close = 0;
206
207 for (i = 0; i != count; i++) {
208 char c;
209 if (get_user(c, buf + i))
210 return -EFAULT;
211 if (c == 'V')
212 eur_expect_close = 42;
213 }
214 }
215 spin_lock(lock: &eurwdt_lock);
216 eurwdt_ping(); /* the default timeout */
217 spin_unlock(lock: &eurwdt_lock);
218 }
219 return count;
220}
221
222/**
223 * eurwdt_ioctl:
224 * @file: file handle to the device
225 * @cmd: watchdog command
226 * @arg: argument pointer
227 *
228 * The watchdog API defines a common set of functions for all watchdogs
229 * according to their available features.
230 */
231
232static long eurwdt_ioctl(struct file *file,
233 unsigned int cmd, unsigned long arg)
234{
235 void __user *argp = (void __user *)arg;
236 int __user *p = argp;
237 static const struct watchdog_info ident = {
238 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
239 | WDIOF_MAGICCLOSE,
240 .firmware_version = 1,
241 .identity = "WDT Eurotech CPU-1220/1410",
242 };
243
244 int time;
245 int options, retval = -EINVAL;
246
247 switch (cmd) {
248 case WDIOC_GETSUPPORT:
249 return copy_to_user(to: argp, from: &ident, n: sizeof(ident)) ? -EFAULT : 0;
250
251 case WDIOC_GETSTATUS:
252 case WDIOC_GETBOOTSTATUS:
253 return put_user(0, p);
254
255 case WDIOC_SETOPTIONS:
256 if (get_user(options, p))
257 return -EFAULT;
258 spin_lock(lock: &eurwdt_lock);
259 if (options & WDIOS_DISABLECARD) {
260 eurwdt_disable_timer();
261 retval = 0;
262 }
263 if (options & WDIOS_ENABLECARD) {
264 eurwdt_activate_timer();
265 eurwdt_ping();
266 retval = 0;
267 }
268 spin_unlock(lock: &eurwdt_lock);
269 return retval;
270
271 case WDIOC_KEEPALIVE:
272 spin_lock(lock: &eurwdt_lock);
273 eurwdt_ping();
274 spin_unlock(lock: &eurwdt_lock);
275 return 0;
276
277 case WDIOC_SETTIMEOUT:
278 if (copy_from_user(to: &time, from: p, n: sizeof(int)))
279 return -EFAULT;
280
281 /* Sanity check */
282 if (time < 0 || time > 255)
283 return -EINVAL;
284
285 spin_lock(lock: &eurwdt_lock);
286 eurwdt_timeout = time;
287 eurwdt_set_timeout(timeout: time);
288 spin_unlock(lock: &eurwdt_lock);
289 fallthrough;
290
291 case WDIOC_GETTIMEOUT:
292 return put_user(eurwdt_timeout, p);
293
294 default:
295 return -ENOTTY;
296 }
297}
298
299/**
300 * eurwdt_open:
301 * @inode: inode of device
302 * @file: file handle to device
303 *
304 * The misc device has been opened. The watchdog device is single
305 * open and on opening we load the counter.
306 */
307
308static int eurwdt_open(struct inode *inode, struct file *file)
309{
310 if (test_and_set_bit(nr: 0, addr: &eurwdt_is_open))
311 return -EBUSY;
312 eurwdt_timeout = WDT_TIMEOUT; /* initial timeout */
313 /* Activate the WDT */
314 eurwdt_activate_timer();
315 return stream_open(inode, filp: file);
316}
317
318/**
319 * eurwdt_release:
320 * @inode: inode to board
321 * @file: file handle to board
322 *
323 * The watchdog has a configurable API. There is a religious dispute
324 * between people who want their watchdog to be able to shut down and
325 * those who want to be sure if the watchdog manager dies the machine
326 * reboots. In the former case we disable the counters, in the latter
327 * case you have to open it again very soon.
328 */
329
330static int eurwdt_release(struct inode *inode, struct file *file)
331{
332 if (eur_expect_close == 42)
333 eurwdt_disable_timer();
334 else {
335 pr_crit("Unexpected close, not stopping watchdog!\n");
336 eurwdt_ping();
337 }
338 clear_bit(nr: 0, addr: &eurwdt_is_open);
339 eur_expect_close = 0;
340 return 0;
341}
342
343/**
344 * eurwdt_notify_sys:
345 * @this: our notifier block
346 * @code: the event being reported
347 * @unused: unused
348 *
349 * Our notifier is called on system shutdowns. We want to turn the card
350 * off at reboot otherwise the machine will reboot again during memory
351 * test or worse yet during the following fsck. This would suck, in fact
352 * trust me - if it happens it does suck.
353 */
354
355static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code,
356 void *unused)
357{
358 if (code == SYS_DOWN || code == SYS_HALT)
359 eurwdt_disable_timer(); /* Turn the card off */
360
361 return NOTIFY_DONE;
362}
363
364/*
365 * Kernel Interfaces
366 */
367
368
369static const struct file_operations eurwdt_fops = {
370 .owner = THIS_MODULE,
371 .write = eurwdt_write,
372 .unlocked_ioctl = eurwdt_ioctl,
373 .compat_ioctl = compat_ptr_ioctl,
374 .open = eurwdt_open,
375 .release = eurwdt_release,
376};
377
378static struct miscdevice eurwdt_miscdev = {
379 .minor = WATCHDOG_MINOR,
380 .name = "watchdog",
381 .fops = &eurwdt_fops,
382};
383
384/*
385 * The WDT card needs to learn about soft shutdowns in order to
386 * turn the timebomb registers off.
387 */
388
389static struct notifier_block eurwdt_notifier = {
390 .notifier_call = eurwdt_notify_sys,
391};
392
393/**
394 * eurwdt_exit:
395 *
396 * Unload the watchdog. You cannot do this with any file handles open.
397 * If your watchdog is set to continue ticking on close and you unload
398 * it, well it keeps ticking. We won't get the interrupt but the board
399 * will not touch PC memory so all is fine. You just have to load a new
400 * module in 60 seconds or reboot.
401 */
402
403static void __exit eurwdt_exit(void)
404{
405 eurwdt_lock_chip();
406
407 misc_deregister(misc: &eurwdt_miscdev);
408
409 unregister_reboot_notifier(&eurwdt_notifier);
410 release_region(io, 2);
411 free_irq(irq, NULL);
412}
413
414/**
415 * eurwdt_init:
416 *
417 * Set up the WDT watchdog board. After grabbing the resources
418 * we require we need also to unlock the device.
419 * The open() function will actually kick the board off.
420 */
421
422static int __init eurwdt_init(void)
423{
424 int ret;
425
426 ret = request_irq(irq, handler: eurwdt_interrupt, flags: 0, name: "eurwdt", NULL);
427 if (ret) {
428 pr_err("IRQ %d is not free\n", irq);
429 goto out;
430 }
431
432 if (!request_region(io, 2, "eurwdt")) {
433 pr_err("IO %X is not free\n", io);
434 ret = -EBUSY;
435 goto outirq;
436 }
437
438 ret = register_reboot_notifier(&eurwdt_notifier);
439 if (ret) {
440 pr_err("can't register reboot notifier (err=%d)\n", ret);
441 goto outreg;
442 }
443
444 ret = misc_register(misc: &eurwdt_miscdev);
445 if (ret) {
446 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
447 goto outreboot;
448 }
449
450 eurwdt_unlock_chip();
451
452 ret = 0;
453 pr_info("Eurotech WDT driver 0.01 at %X (Interrupt %d) - timeout event: %s\n",
454 io, irq, (!strcmp("int", ev) ? "int" : "reboot"));
455
456out:
457 return ret;
458
459outreboot:
460 unregister_reboot_notifier(&eurwdt_notifier);
461
462outreg:
463 release_region(io, 2);
464
465outirq:
466 free_irq(irq, NULL);
467 goto out;
468}
469
470module_init(eurwdt_init);
471module_exit(eurwdt_exit);
472
473MODULE_AUTHOR("Rodolfo Giometti");
474MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog");
475MODULE_LICENSE("GPL");
476

source code of linux/drivers/watchdog/eurotechwdt.c