1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
4 * (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>,
5 * All Rights Reserved.
6 * Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
7 *
8 * The author(s) of this software shall not be held liable for damages
9 * of any nature resulting due to the use of this software. This
10 * software is provided AS-IS with no warranties.
11 *
12 * Changelog:
13 * 20020220 Zwane Mwaikambo Code based on datasheet, no hardware.
14 * 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik
15 * and Alan Cox.
16 * 20020222 Zwane Mwaikambo Added probing.
17 * 20020225 Zwane Mwaikambo Added ISAPNP support.
18 * 20020412 Rob Radez Broke out start/stop functions
19 * <rob@osinvestor.com> Return proper status instead of
20 * temperature warning
21 * Add WDIOC_GETBOOTSTATUS and
22 * WDIOC_SETOPTIONS ioctls
23 * Fix CONFIG_WATCHDOG_NOWAYOUT
24 * 20020530 Joel Becker Add Matt Domsch's nowayout module
25 * option
26 * 20030116 Adam Belay Updated to the latest pnp code
27 */
28
29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30
31 #include <linux/module.h>
32 #include <linux/moduleparam.h>
33 #include <linux/miscdevice.h>
34 #include <linux/watchdog.h>
35 #include <linux/ioport.h>
36 #include <linux/spinlock.h>
37 #include <linux/notifier.h>
38 #include <linux/reboot.h>
39 #include <linux/init.h>
40 #include <linux/pnp.h>
41 #include <linux/fs.h>
42 #include <linux/semaphore.h>
43 #include <linux/io.h>
44 #include <linux/uaccess.h>
45
46 #define SC1200_MODULE_VER "build 20020303"
47 #define SC1200_MODULE_NAME "sc1200wdt"
48
49 #define MAX_TIMEOUT 255 /* 255 minutes */
50 #define PMIR (io) /* Power Management Index Register */
51 #define PMDR (io+1) /* Power Management Data Register */
52
53 /* Data Register indexes */
54 #define FER1 0x00 /* Function enable register 1 */
55 #define FER2 0x01 /* Function enable register 2 */
56 #define PMC1 0x02 /* Power Management Ctrl 1 */
57 #define PMC2 0x03 /* Power Management Ctrl 2 */
58 #define PMC3 0x04 /* Power Management Ctrl 3 */
59 #define WDTO 0x05 /* Watchdog timeout register */
60 #define WDCF 0x06 /* Watchdog config register */
61 #define WDST 0x07 /* Watchdog status register */
62
63 /* WDCF bitfields - which devices assert WDO */
64 #define KBC_IRQ 0x01 /* Keyboard Controller */
65 #define MSE_IRQ 0x02 /* Mouse */
66 #define UART1_IRQ 0x03 /* Serial0 */
67 #define UART2_IRQ 0x04 /* Serial1 */
68 /* 5 -7 are reserved */
69
70 static int timeout = 1;
71 static int io = -1;
72 static int io_len = 2; /* for non plug and play */
73 static unsigned long open_flag;
74 static char expect_close;
75 static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */
76
77 #if defined CONFIG_PNP
78 static int isapnp = 1;
79 static struct pnp_dev *wdt_dev;
80
81 module_param(isapnp, int, 0);
82 MODULE_PARM_DESC(isapnp,
83 "When set to 0 driver ISA PnP support will be disabled");
84 #endif
85
86 module_param_hw(io, int, ioport, 0);
87 MODULE_PARM_DESC(io, "io port");
88 module_param(timeout, int, 0);
89 MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
90
91 static bool nowayout = WATCHDOG_NOWAYOUT;
92 module_param(nowayout, bool, 0);
93 MODULE_PARM_DESC(nowayout,
94 "Watchdog cannot be stopped once started (default="
95 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
96
97
98
99 /* Read from Data Register */
__sc1200wdt_read_data(unsigned char index,unsigned char * data)100 static inline void __sc1200wdt_read_data(unsigned char index,
101 unsigned char *data)
102 {
103 outb_p(index, PMIR);
104 *data = inb(PMDR);
105 }
106
sc1200wdt_read_data(unsigned char index,unsigned char * data)107 static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
108 {
109 spin_lock(&sc1200wdt_lock);
110 __sc1200wdt_read_data(index, data);
111 spin_unlock(&sc1200wdt_lock);
112 }
113
114 /* Write to Data Register */
__sc1200wdt_write_data(unsigned char index,unsigned char data)115 static inline void __sc1200wdt_write_data(unsigned char index,
116 unsigned char data)
117 {
118 outb_p(index, PMIR);
119 outb(data, PMDR);
120 }
121
sc1200wdt_write_data(unsigned char index,unsigned char data)122 static inline void sc1200wdt_write_data(unsigned char index,
123 unsigned char data)
124 {
125 spin_lock(&sc1200wdt_lock);
126 __sc1200wdt_write_data(index, data);
127 spin_unlock(&sc1200wdt_lock);
128 }
129
130
sc1200wdt_start(void)131 static void sc1200wdt_start(void)
132 {
133 unsigned char reg;
134 spin_lock(&sc1200wdt_lock);
135
136 __sc1200wdt_read_data(WDCF, ®);
137 /* assert WDO when any of the following interrupts are triggered too */
138 reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
139 __sc1200wdt_write_data(WDCF, reg);
140 /* set the timeout and get the ball rolling */
141 __sc1200wdt_write_data(WDTO, timeout);
142
143 spin_unlock(&sc1200wdt_lock);
144 }
145
sc1200wdt_stop(void)146 static void sc1200wdt_stop(void)
147 {
148 sc1200wdt_write_data(WDTO, 0);
149 }
150
151 /* This returns the status of the WDO signal, inactive high. */
sc1200wdt_status(void)152 static inline int sc1200wdt_status(void)
153 {
154 unsigned char ret;
155
156 sc1200wdt_read_data(WDST, &ret);
157 /* If the bit is inactive, the watchdog is enabled, so return
158 * KEEPALIVEPING which is a bit of a kludge because there's nothing
159 * else for enabled/disabled status
160 */
161 return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
162 }
163
sc1200wdt_open(struct inode * inode,struct file * file)164 static int sc1200wdt_open(struct inode *inode, struct file *file)
165 {
166 /* allow one at a time */
167 if (test_and_set_bit(0, &open_flag))
168 return -EBUSY;
169
170 if (timeout > MAX_TIMEOUT)
171 timeout = MAX_TIMEOUT;
172
173 sc1200wdt_start();
174 pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
175
176 return stream_open(inode, file);
177 }
178
179
sc1200wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)180 static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
181 unsigned long arg)
182 {
183 int new_timeout;
184 void __user *argp = (void __user *)arg;
185 int __user *p = argp;
186 static const struct watchdog_info ident = {
187 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
188 WDIOF_MAGICCLOSE,
189 .firmware_version = 0,
190 .identity = "PC87307/PC97307",
191 };
192
193 switch (cmd) {
194 case WDIOC_GETSUPPORT:
195 if (copy_to_user(argp, &ident, sizeof(ident)))
196 return -EFAULT;
197 return 0;
198
199 case WDIOC_GETSTATUS:
200 return put_user(sc1200wdt_status(), p);
201
202 case WDIOC_GETBOOTSTATUS:
203 return put_user(0, p);
204
205 case WDIOC_SETOPTIONS:
206 {
207 int options, retval = -EINVAL;
208
209 if (get_user(options, p))
210 return -EFAULT;
211
212 if (options & WDIOS_DISABLECARD) {
213 sc1200wdt_stop();
214 retval = 0;
215 }
216
217 if (options & WDIOS_ENABLECARD) {
218 sc1200wdt_start();
219 retval = 0;
220 }
221
222 return retval;
223 }
224 case WDIOC_KEEPALIVE:
225 sc1200wdt_write_data(WDTO, timeout);
226 return 0;
227
228 case WDIOC_SETTIMEOUT:
229 if (get_user(new_timeout, p))
230 return -EFAULT;
231 /* the API states this is given in secs */
232 new_timeout /= 60;
233 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
234 return -EINVAL;
235 timeout = new_timeout;
236 sc1200wdt_write_data(WDTO, timeout);
237 fallthrough; /* and return the new timeout */
238
239 case WDIOC_GETTIMEOUT:
240 return put_user(timeout * 60, p);
241
242 default:
243 return -ENOTTY;
244 }
245 }
246
247
sc1200wdt_release(struct inode * inode,struct file * file)248 static int sc1200wdt_release(struct inode *inode, struct file *file)
249 {
250 if (expect_close == 42) {
251 sc1200wdt_stop();
252 pr_info("Watchdog disabled\n");
253 } else {
254 sc1200wdt_write_data(WDTO, timeout);
255 pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
256 }
257 clear_bit(0, &open_flag);
258 expect_close = 0;
259
260 return 0;
261 }
262
263
sc1200wdt_write(struct file * file,const char __user * data,size_t len,loff_t * ppos)264 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
265 size_t len, loff_t *ppos)
266 {
267 if (len) {
268 if (!nowayout) {
269 size_t i;
270
271 expect_close = 0;
272
273 for (i = 0; i != len; i++) {
274 char c;
275
276 if (get_user(c, data + i))
277 return -EFAULT;
278 if (c == 'V')
279 expect_close = 42;
280 }
281 }
282
283 sc1200wdt_write_data(WDTO, timeout);
284 return len;
285 }
286
287 return 0;
288 }
289
290
sc1200wdt_notify_sys(struct notifier_block * this,unsigned long code,void * unused)291 static int sc1200wdt_notify_sys(struct notifier_block *this,
292 unsigned long code, void *unused)
293 {
294 if (code == SYS_DOWN || code == SYS_HALT)
295 sc1200wdt_stop();
296
297 return NOTIFY_DONE;
298 }
299
300
301 static struct notifier_block sc1200wdt_notifier = {
302 .notifier_call = sc1200wdt_notify_sys,
303 };
304
305 static const struct file_operations sc1200wdt_fops = {
306 .owner = THIS_MODULE,
307 .llseek = no_llseek,
308 .write = sc1200wdt_write,
309 .unlocked_ioctl = sc1200wdt_ioctl,
310 .compat_ioctl = compat_ptr_ioctl,
311 .open = sc1200wdt_open,
312 .release = sc1200wdt_release,
313 };
314
315 static struct miscdevice sc1200wdt_miscdev = {
316 .minor = WATCHDOG_MINOR,
317 .name = "watchdog",
318 .fops = &sc1200wdt_fops,
319 };
320
321
sc1200wdt_probe(void)322 static int __init sc1200wdt_probe(void)
323 {
324 /* The probe works by reading the PMC3 register's default value of 0x0e
325 * there is one caveat, if the device disables the parallel port or any
326 * of the UARTs we won't be able to detect it.
327 * NB. This could be done with accuracy by reading the SID registers,
328 * but we don't have access to those io regions.
329 */
330
331 unsigned char reg;
332
333 sc1200wdt_read_data(PMC3, ®);
334 reg &= 0x0f; /* we don't want the UART busy bits */
335 return (reg == 0x0e) ? 0 : -ENODEV;
336 }
337
338
339 #if defined CONFIG_PNP
340
341 static const struct pnp_device_id scl200wdt_pnp_devices[] = {
342 /* National Semiconductor PC87307/PC97307 watchdog component */
343 {.id = "NSC0800", .driver_data = 0},
344 {.id = ""},
345 };
346
scl200wdt_pnp_probe(struct pnp_dev * dev,const struct pnp_device_id * dev_id)347 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
348 const struct pnp_device_id *dev_id)
349 {
350 /* this driver only supports one card at a time */
351 if (wdt_dev || !isapnp)
352 return -EBUSY;
353
354 wdt_dev = dev;
355 io = pnp_port_start(wdt_dev, 0);
356 io_len = pnp_port_len(wdt_dev, 0);
357
358 if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
359 pr_err("Unable to register IO port %#x\n", io);
360 return -EBUSY;
361 }
362
363 pr_info("PnP device found at io port %#x/%d\n", io, io_len);
364 return 0;
365 }
366
scl200wdt_pnp_remove(struct pnp_dev * dev)367 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
368 {
369 if (wdt_dev) {
370 release_region(io, io_len);
371 wdt_dev = NULL;
372 }
373 }
374
375 static struct pnp_driver scl200wdt_pnp_driver = {
376 .name = "scl200wdt",
377 .id_table = scl200wdt_pnp_devices,
378 .probe = scl200wdt_pnp_probe,
379 .remove = scl200wdt_pnp_remove,
380 };
381
382 #endif /* CONFIG_PNP */
383
384
sc1200wdt_init(void)385 static int __init sc1200wdt_init(void)
386 {
387 int ret;
388
389 pr_info("%s\n", SC1200_MODULE_VER);
390
391 #if defined CONFIG_PNP
392 if (isapnp) {
393 ret = pnp_register_driver(&scl200wdt_pnp_driver);
394 if (ret)
395 goto out_clean;
396 }
397 #endif
398
399 if (io == -1) {
400 pr_err("io parameter must be specified\n");
401 ret = -EINVAL;
402 goto out_pnp;
403 }
404
405 #if defined CONFIG_PNP
406 /* now that the user has specified an IO port and we haven't detected
407 * any devices, disable pnp support */
408 if (isapnp)
409 pnp_unregister_driver(&scl200wdt_pnp_driver);
410 isapnp = 0;
411 #endif
412
413 if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
414 pr_err("Unable to register IO port %#x\n", io);
415 ret = -EBUSY;
416 goto out_pnp;
417 }
418
419 ret = sc1200wdt_probe();
420 if (ret)
421 goto out_io;
422
423 ret = register_reboot_notifier(&sc1200wdt_notifier);
424 if (ret) {
425 pr_err("Unable to register reboot notifier err = %d\n", ret);
426 goto out_io;
427 }
428
429 ret = misc_register(&sc1200wdt_miscdev);
430 if (ret) {
431 pr_err("Unable to register miscdev on minor %d\n",
432 WATCHDOG_MINOR);
433 goto out_rbt;
434 }
435
436 /* ret = 0 */
437
438 out_clean:
439 return ret;
440
441 out_rbt:
442 unregister_reboot_notifier(&sc1200wdt_notifier);
443
444 out_io:
445 release_region(io, io_len);
446
447 out_pnp:
448 #if defined CONFIG_PNP
449 if (isapnp)
450 pnp_unregister_driver(&scl200wdt_pnp_driver);
451 #endif
452 goto out_clean;
453 }
454
455
sc1200wdt_exit(void)456 static void __exit sc1200wdt_exit(void)
457 {
458 misc_deregister(&sc1200wdt_miscdev);
459 unregister_reboot_notifier(&sc1200wdt_notifier);
460
461 #if defined CONFIG_PNP
462 if (isapnp)
463 pnp_unregister_driver(&scl200wdt_pnp_driver);
464 else
465 #endif
466 release_region(io, io_len);
467 }
468
469 module_init(sc1200wdt_init);
470 module_exit(sc1200wdt_exit);
471
472 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
473 MODULE_DESCRIPTION(
474 "Driver for National Semiconductor PC87307/PC97307 watchdog component");
475 MODULE_LICENSE("GPL");
476
