1 /*
2 * National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
3 * (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>,
4 * All Rights Reserved.
5 * Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * The author(s) of this software shall not be held liable for damages
13 * of any nature resulting due to the use of this software. This
14 * software is provided AS-IS with no warranties.
15 *
16 * Changelog:
17 * 20020220 Zwane Mwaikambo Code based on datasheet, no hardware.
18 * 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik
19 * and Alan Cox.
20 * 20020222 Zwane Mwaikambo Added probing.
21 * 20020225 Zwane Mwaikambo Added ISAPNP support.
22 * 20020412 Rob Radez Broke out start/stop functions
23 * <rob@osinvestor.com> Return proper status instead of
24 * temperature warning
25 * Add WDIOC_GETBOOTSTATUS and
26 * WDIOC_SETOPTIONS ioctls
27 * Fix CONFIG_WATCHDOG_NOWAYOUT
28 * 20020530 Joel Becker Add Matt Domsch's nowayout module
29 * option
30 * 20030116 Adam Belay Updated to the latest pnp code
31 *
32 */
33
34 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35
36 #include <linux/module.h>
37 #include <linux/moduleparam.h>
38 #include <linux/miscdevice.h>
39 #include <linux/watchdog.h>
40 #include <linux/ioport.h>
41 #include <linux/spinlock.h>
42 #include <linux/notifier.h>
43 #include <linux/reboot.h>
44 #include <linux/init.h>
45 #include <linux/pnp.h>
46 #include <linux/fs.h>
47 #include <linux/semaphore.h>
48 #include <linux/io.h>
49 #include <linux/uaccess.h>
50
51 #define SC1200_MODULE_VER "build 20020303"
52 #define SC1200_MODULE_NAME "sc1200wdt"
53
54 #define MAX_TIMEOUT 255 /* 255 minutes */
55 #define PMIR (io) /* Power Management Index Register */
56 #define PMDR (io+1) /* Power Management Data Register */
57
58 /* Data Register indexes */
59 #define FER1 0x00 /* Function enable register 1 */
60 #define FER2 0x01 /* Function enable register 2 */
61 #define PMC1 0x02 /* Power Management Ctrl 1 */
62 #define PMC2 0x03 /* Power Management Ctrl 2 */
63 #define PMC3 0x04 /* Power Management Ctrl 3 */
64 #define WDTO 0x05 /* Watchdog timeout register */
65 #define WDCF 0x06 /* Watchdog config register */
66 #define WDST 0x07 /* Watchdog status register */
67
68 /* WDCF bitfields - which devices assert WDO */
69 #define KBC_IRQ 0x01 /* Keyboard Controller */
70 #define MSE_IRQ 0x02 /* Mouse */
71 #define UART1_IRQ 0x03 /* Serial0 */
72 #define UART2_IRQ 0x04 /* Serial1 */
73 /* 5 -7 are reserved */
74
75 static int timeout = 1;
76 static int io = -1;
77 static int io_len = 2; /* for non plug and play */
78 static unsigned long open_flag;
79 static char expect_close;
80 static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */
81
82 #if defined CONFIG_PNP
83 static int isapnp = 1;
84 static struct pnp_dev *wdt_dev;
85
86 module_param(isapnp, int, 0);
87 MODULE_PARM_DESC(isapnp,
88 "When set to 0 driver ISA PnP support will be disabled");
89 #endif
90
91 module_param_hw(io, int, ioport, 0);
92 MODULE_PARM_DESC(io, "io port");
93 module_param(timeout, int, 0);
94 MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
95
96 static bool nowayout = WATCHDOG_NOWAYOUT;
97 module_param(nowayout, bool, 0);
98 MODULE_PARM_DESC(nowayout,
99 "Watchdog cannot be stopped once started (default="
100 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
101
102
103
104 /* Read from Data Register */
__sc1200wdt_read_data(unsigned char index,unsigned char * data)105 static inline void __sc1200wdt_read_data(unsigned char index,
106 unsigned char *data)
107 {
108 outb_p(index, PMIR);
109 *data = inb(PMDR);
110 }
111
sc1200wdt_read_data(unsigned char index,unsigned char * data)112 static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
113 {
114 spin_lock(&sc1200wdt_lock);
115 __sc1200wdt_read_data(index, data);
116 spin_unlock(&sc1200wdt_lock);
117 }
118
119 /* Write to Data Register */
__sc1200wdt_write_data(unsigned char index,unsigned char data)120 static inline void __sc1200wdt_write_data(unsigned char index,
121 unsigned char data)
122 {
123 outb_p(index, PMIR);
124 outb(data, PMDR);
125 }
126
sc1200wdt_write_data(unsigned char index,unsigned char data)127 static inline void sc1200wdt_write_data(unsigned char index,
128 unsigned char data)
129 {
130 spin_lock(&sc1200wdt_lock);
131 __sc1200wdt_write_data(index, data);
132 spin_unlock(&sc1200wdt_lock);
133 }
134
135
sc1200wdt_start(void)136 static void sc1200wdt_start(void)
137 {
138 unsigned char reg;
139 spin_lock(&sc1200wdt_lock);
140
141 __sc1200wdt_read_data(WDCF, ®);
142 /* assert WDO when any of the following interrupts are triggered too */
143 reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
144 __sc1200wdt_write_data(WDCF, reg);
145 /* set the timeout and get the ball rolling */
146 __sc1200wdt_write_data(WDTO, timeout);
147
148 spin_unlock(&sc1200wdt_lock);
149 }
150
sc1200wdt_stop(void)151 static void sc1200wdt_stop(void)
152 {
153 sc1200wdt_write_data(WDTO, 0);
154 }
155
156 /* This returns the status of the WDO signal, inactive high. */
sc1200wdt_status(void)157 static inline int sc1200wdt_status(void)
158 {
159 unsigned char ret;
160
161 sc1200wdt_read_data(WDST, &ret);
162 /* If the bit is inactive, the watchdog is enabled, so return
163 * KEEPALIVEPING which is a bit of a kludge because there's nothing
164 * else for enabled/disabled status
165 */
166 return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
167 }
168
sc1200wdt_open(struct inode * inode,struct file * file)169 static int sc1200wdt_open(struct inode *inode, struct file *file)
170 {
171 /* allow one at a time */
172 if (test_and_set_bit(0, &open_flag))
173 return -EBUSY;
174
175 if (timeout > MAX_TIMEOUT)
176 timeout = MAX_TIMEOUT;
177
178 sc1200wdt_start();
179 pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
180
181 return nonseekable_open(inode, file);
182 }
183
184
sc1200wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)185 static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
186 unsigned long arg)
187 {
188 int new_timeout;
189 void __user *argp = (void __user *)arg;
190 int __user *p = argp;
191 static const struct watchdog_info ident = {
192 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
193 WDIOF_MAGICCLOSE,
194 .firmware_version = 0,
195 .identity = "PC87307/PC97307",
196 };
197
198 switch (cmd) {
199 case WDIOC_GETSUPPORT:
200 if (copy_to_user(argp, &ident, sizeof(ident)))
201 return -EFAULT;
202 return 0;
203
204 case WDIOC_GETSTATUS:
205 return put_user(sc1200wdt_status(), p);
206
207 case WDIOC_GETBOOTSTATUS:
208 return put_user(0, p);
209
210 case WDIOC_SETOPTIONS:
211 {
212 int options, retval = -EINVAL;
213
214 if (get_user(options, p))
215 return -EFAULT;
216
217 if (options & WDIOS_DISABLECARD) {
218 sc1200wdt_stop();
219 retval = 0;
220 }
221
222 if (options & WDIOS_ENABLECARD) {
223 sc1200wdt_start();
224 retval = 0;
225 }
226
227 return retval;
228 }
229 case WDIOC_KEEPALIVE:
230 sc1200wdt_write_data(WDTO, timeout);
231 return 0;
232
233 case WDIOC_SETTIMEOUT:
234 if (get_user(new_timeout, p))
235 return -EFAULT;
236 /* the API states this is given in secs */
237 new_timeout /= 60;
238 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
239 return -EINVAL;
240 timeout = new_timeout;
241 sc1200wdt_write_data(WDTO, timeout);
242 /* fall through and return the new timeout */
243
244 case WDIOC_GETTIMEOUT:
245 return put_user(timeout * 60, p);
246
247 default:
248 return -ENOTTY;
249 }
250 }
251
252
sc1200wdt_release(struct inode * inode,struct file * file)253 static int sc1200wdt_release(struct inode *inode, struct file *file)
254 {
255 if (expect_close == 42) {
256 sc1200wdt_stop();
257 pr_info("Watchdog disabled\n");
258 } else {
259 sc1200wdt_write_data(WDTO, timeout);
260 pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
261 }
262 clear_bit(0, &open_flag);
263 expect_close = 0;
264
265 return 0;
266 }
267
268
sc1200wdt_write(struct file * file,const char __user * data,size_t len,loff_t * ppos)269 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
270 size_t len, loff_t *ppos)
271 {
272 if (len) {
273 if (!nowayout) {
274 size_t i;
275
276 expect_close = 0;
277
278 for (i = 0; i != len; i++) {
279 char c;
280
281 if (get_user(c, data + i))
282 return -EFAULT;
283 if (c == 'V')
284 expect_close = 42;
285 }
286 }
287
288 sc1200wdt_write_data(WDTO, timeout);
289 return len;
290 }
291
292 return 0;
293 }
294
295
sc1200wdt_notify_sys(struct notifier_block * this,unsigned long code,void * unused)296 static int sc1200wdt_notify_sys(struct notifier_block *this,
297 unsigned long code, void *unused)
298 {
299 if (code == SYS_DOWN || code == SYS_HALT)
300 sc1200wdt_stop();
301
302 return NOTIFY_DONE;
303 }
304
305
306 static struct notifier_block sc1200wdt_notifier = {
307 .notifier_call = sc1200wdt_notify_sys,
308 };
309
310 static const struct file_operations sc1200wdt_fops = {
311 .owner = THIS_MODULE,
312 .llseek = no_llseek,
313 .write = sc1200wdt_write,
314 .unlocked_ioctl = sc1200wdt_ioctl,
315 .open = sc1200wdt_open,
316 .release = sc1200wdt_release,
317 };
318
319 static struct miscdevice sc1200wdt_miscdev = {
320 .minor = WATCHDOG_MINOR,
321 .name = "watchdog",
322 .fops = &sc1200wdt_fops,
323 };
324
325
sc1200wdt_probe(void)326 static int __init sc1200wdt_probe(void)
327 {
328 /* The probe works by reading the PMC3 register's default value of 0x0e
329 * there is one caveat, if the device disables the parallel port or any
330 * of the UARTs we won't be able to detect it.
331 * NB. This could be done with accuracy by reading the SID registers,
332 * but we don't have access to those io regions.
333 */
334
335 unsigned char reg;
336
337 sc1200wdt_read_data(PMC3, ®);
338 reg &= 0x0f; /* we don't want the UART busy bits */
339 return (reg == 0x0e) ? 0 : -ENODEV;
340 }
341
342
343 #if defined CONFIG_PNP
344
345 static const struct pnp_device_id scl200wdt_pnp_devices[] = {
346 /* National Semiconductor PC87307/PC97307 watchdog component */
347 {.id = "NSC0800", .driver_data = 0},
348 {.id = ""},
349 };
350
scl200wdt_pnp_probe(struct pnp_dev * dev,const struct pnp_device_id * dev_id)351 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
352 const struct pnp_device_id *dev_id)
353 {
354 /* this driver only supports one card at a time */
355 if (wdt_dev || !isapnp)
356 return -EBUSY;
357
358 wdt_dev = dev;
359 io = pnp_port_start(wdt_dev, 0);
360 io_len = pnp_port_len(wdt_dev, 0);
361
362 if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
363 pr_err("Unable to register IO port %#x\n", io);
364 return -EBUSY;
365 }
366
367 pr_info("PnP device found at io port %#x/%d\n", io, io_len);
368 return 0;
369 }
370
scl200wdt_pnp_remove(struct pnp_dev * dev)371 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
372 {
373 if (wdt_dev) {
374 release_region(io, io_len);
375 wdt_dev = NULL;
376 }
377 }
378
379 static struct pnp_driver scl200wdt_pnp_driver = {
380 .name = "scl200wdt",
381 .id_table = scl200wdt_pnp_devices,
382 .probe = scl200wdt_pnp_probe,
383 .remove = scl200wdt_pnp_remove,
384 };
385
386 #endif /* CONFIG_PNP */
387
388
sc1200wdt_init(void)389 static int __init sc1200wdt_init(void)
390 {
391 int ret;
392
393 pr_info("%s\n", SC1200_MODULE_VER);
394
395 #if defined CONFIG_PNP
396 if (isapnp) {
397 ret = pnp_register_driver(&scl200wdt_pnp_driver);
398 if (ret)
399 goto out_clean;
400 }
401 #endif
402
403 if (io == -1) {
404 pr_err("io parameter must be specified\n");
405 ret = -EINVAL;
406 goto out_pnp;
407 }
408
409 #if defined CONFIG_PNP
410 /* now that the user has specified an IO port and we haven't detected
411 * any devices, disable pnp support */
412 if (isapnp)
413 pnp_unregister_driver(&scl200wdt_pnp_driver);
414 isapnp = 0;
415 #endif
416
417 if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
418 pr_err("Unable to register IO port %#x\n", io);
419 ret = -EBUSY;
420 goto out_pnp;
421 }
422
423 ret = sc1200wdt_probe();
424 if (ret)
425 goto out_io;
426
427 ret = register_reboot_notifier(&sc1200wdt_notifier);
428 if (ret) {
429 pr_err("Unable to register reboot notifier err = %d\n", ret);
430 goto out_io;
431 }
432
433 ret = misc_register(&sc1200wdt_miscdev);
434 if (ret) {
435 pr_err("Unable to register miscdev on minor %d\n",
436 WATCHDOG_MINOR);
437 goto out_rbt;
438 }
439
440 /* ret = 0 */
441
442 out_clean:
443 return ret;
444
445 out_rbt:
446 unregister_reboot_notifier(&sc1200wdt_notifier);
447
448 out_io:
449 release_region(io, io_len);
450
451 out_pnp:
452 #if defined CONFIG_PNP
453 if (isapnp)
454 pnp_unregister_driver(&scl200wdt_pnp_driver);
455 #endif
456 goto out_clean;
457 }
458
459
sc1200wdt_exit(void)460 static void __exit sc1200wdt_exit(void)
461 {
462 misc_deregister(&sc1200wdt_miscdev);
463 unregister_reboot_notifier(&sc1200wdt_notifier);
464
465 #if defined CONFIG_PNP
466 if (isapnp)
467 pnp_unregister_driver(&scl200wdt_pnp_driver);
468 else
469 #endif
470 release_region(io, io_len);
471 }
472
473 module_init(sc1200wdt_init);
474 module_exit(sc1200wdt_exit);
475
476 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
477 MODULE_DESCRIPTION(
478 "Driver for National Semiconductor PC87307/PC97307 watchdog component");
479 MODULE_LICENSE("GPL");
480
