f3bdc8227cc40bffeb6386cf582bd063f412287f
[linux-2.6.git] / drivers / watchdog / sc1200wdt.c
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 #include <linux/module.h>
35 #include <linux/moduleparam.h>
36 #include <linux/miscdevice.h>
37 #include <linux/watchdog.h>
38 #include <linux/ioport.h>
39 #include <linux/spinlock.h>
40 #include <linux/notifier.h>
41 #include <linux/reboot.h>
42 #include <linux/init.h>
43 #include <linux/pnp.h>
44 #include <linux/fs.h>
45 #include <linux/semaphore.h>
46 #include <linux/io.h>
47 #include <linux/uaccess.h>
48
49 #define SC1200_MODULE_VER       "build 20020303"
50 #define SC1200_MODULE_NAME      "sc1200wdt"
51 #define PFX                     SC1200_MODULE_NAME ": "
52
53 #define MAX_TIMEOUT     255     /* 255 minutes */
54 #define PMIR            (io)    /* Power Management Index Register */
55 #define PMDR            (io+1)  /* Power Management Data Register */
56
57 /* Data Register indexes */
58 #define FER1            0x00    /* Function enable register 1 */
59 #define FER2            0x01    /* Function enable register 2 */
60 #define PMC1            0x02    /* Power Management Ctrl 1 */
61 #define PMC2            0x03    /* Power Management Ctrl 2 */
62 #define PMC3            0x04    /* Power Management Ctrl 3 */
63 #define WDTO            0x05    /* Watchdog timeout register */
64 #define WDCF            0x06    /* Watchdog config register */
65 #define WDST            0x07    /* Watchdog status register */
66
67 /* WDCF bitfields - which devices assert WDO */
68 #define KBC_IRQ         0x01    /* Keyboard Controller */
69 #define MSE_IRQ         0x02    /* Mouse */
70 #define UART1_IRQ       0x03    /* Serial0 */
71 #define UART2_IRQ       0x04    /* Serial1 */
72 /* 5 -7 are reserved */
73
74 static char banner[] __initdata = KERN_INFO PFX SC1200_MODULE_VER;
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(io, int, 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 int nowayout = WATCHDOG_NOWAYOUT;
97 module_param(nowayout, int, 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 */
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
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 */
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
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
136 static void sc1200wdt_start(void)
137 {
138         unsigned char reg;
139         spin_lock(&sc1200wdt_lock);
140
141         __sc1200wdt_read_data(WDCF, &reg);
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
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. */
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
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         printk(KERN_INFO PFX "Watchdog enabled, timeout = %d min(s)", timeout);
180
181         return nonseekable_open(inode, file);
182 }
183
184
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
253 static int sc1200wdt_release(struct inode *inode, struct file *file)
254 {
255         if (expect_close == 42) {
256                 sc1200wdt_stop();
257                 printk(KERN_INFO PFX "Watchdog disabled\n");
258         } else {
259                 sc1200wdt_write_data(WDTO, timeout);
260                 printk(KERN_CRIT PFX
261                         "Unexpected close!, timeout = %d min(s)\n", timeout);
262         }
263         clear_bit(0, &open_flag);
264         expect_close = 0;
265
266         return 0;
267 }
268
269
270 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
271                                                 size_t len, loff_t *ppos)
272 {
273         if (len) {
274                 if (!nowayout) {
275                         size_t i;
276
277                         expect_close = 0;
278
279                         for (i = 0; i != len; i++) {
280                                 char c;
281
282                                 if (get_user(c, data+i))
283                                         return -EFAULT;
284                                 if (c == 'V')
285                                         expect_close = 42;
286                         }
287                 }
288
289                 sc1200wdt_write_data(WDTO, timeout);
290                 return len;
291         }
292
293         return 0;
294 }
295
296
297 static int sc1200wdt_notify_sys(struct notifier_block *this,
298                                         unsigned long code, void *unused)
299 {
300         if (code == SYS_DOWN || code == SYS_HALT)
301                 sc1200wdt_stop();
302
303         return NOTIFY_DONE;
304 }
305
306
307 static struct notifier_block sc1200wdt_notifier = {
308         .notifier_call =        sc1200wdt_notify_sys,
309 };
310
311 static const struct file_operations sc1200wdt_fops = {
312         .owner          = THIS_MODULE,
313         .llseek         = no_llseek,
314         .write          = sc1200wdt_write,
315         .unlocked_ioctl = sc1200wdt_ioctl,
316         .open           = sc1200wdt_open,
317         .release        = sc1200wdt_release,
318 };
319
320 static struct miscdevice sc1200wdt_miscdev = {
321         .minor          = WATCHDOG_MINOR,
322         .name           = "watchdog",
323         .fops           = &sc1200wdt_fops,
324 };
325
326
327 static int __init sc1200wdt_probe(void)
328 {
329         /* The probe works by reading the PMC3 register's default value of 0x0e
330          * there is one caveat, if the device disables the parallel port or any
331          * of the UARTs we won't be able to detect it.
332          * NB. This could be done with accuracy by reading the SID registers,
333          * but we don't have access to those io regions.
334          */
335
336         unsigned char reg;
337
338         sc1200wdt_read_data(PMC3, &reg);
339         reg &= 0x0f;            /* we don't want the UART busy bits */
340         return (reg == 0x0e) ? 0 : -ENODEV;
341 }
342
343
344 #if defined CONFIG_PNP
345
346 static struct pnp_device_id scl200wdt_pnp_devices[] = {
347         /* National Semiconductor PC87307/PC97307 watchdog component */
348         {.id = "NSC0800", .driver_data = 0},
349         {.id = ""},
350 };
351
352 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
353                                         const struct pnp_device_id *dev_id)
354 {
355         /* this driver only supports one card at a time */
356         if (wdt_dev || !isapnp)
357                 return -EBUSY;
358
359         wdt_dev = dev;
360         io = pnp_port_start(wdt_dev, 0);
361         io_len = pnp_port_len(wdt_dev, 0);
362
363         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
364                 printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
365                 return -EBUSY;
366         }
367
368         printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n",
369                                                                 io, io_len);
370         return 0;
371 }
372
373 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
374 {
375         if (wdt_dev) {
376                 release_region(io, io_len);
377                 wdt_dev = NULL;
378         }
379 }
380
381 static struct pnp_driver scl200wdt_pnp_driver = {
382         .name           = "scl200wdt",
383         .id_table       = scl200wdt_pnp_devices,
384         .probe          = scl200wdt_pnp_probe,
385         .remove         = scl200wdt_pnp_remove,
386 };
387
388 #endif /* CONFIG_PNP */
389
390
391 static int __init sc1200wdt_init(void)
392 {
393         int ret;
394
395         printk("%s\n", banner);
396
397 #if defined CONFIG_PNP
398         if (isapnp) {
399                 ret = pnp_register_driver(&scl200wdt_pnp_driver);
400                 if (ret)
401                         goto out_clean;
402         }
403 #endif
404
405         if (io == -1) {
406                 printk(KERN_ERR PFX "io parameter must be specified\n");
407                 ret = -EINVAL;
408                 goto out_pnp;
409         }
410
411 #if defined CONFIG_PNP
412         /* now that the user has specified an IO port and we haven't detected
413          * any devices, disable pnp support */
414         isapnp = 0;
415         pnp_unregister_driver(&scl200wdt_pnp_driver);
416 #endif
417
418         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
419                 printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
420                 ret = -EBUSY;
421                 goto out_pnp;
422         }
423
424         ret = sc1200wdt_probe();
425         if (ret)
426                 goto out_io;
427
428         ret = register_reboot_notifier(&sc1200wdt_notifier);
429         if (ret) {
430                 printk(KERN_ERR PFX
431                         "Unable to register reboot notifier err = %d\n", ret);
432                 goto out_io;
433         }
434
435         ret = misc_register(&sc1200wdt_miscdev);
436         if (ret) {
437                 printk(KERN_ERR PFX
438                         "Unable to register miscdev on minor %d\n",
439                                                         WATCHDOG_MINOR);
440                 goto out_rbt;
441         }
442
443         /* ret = 0 */
444
445 out_clean:
446         return ret;
447
448 out_rbt:
449         unregister_reboot_notifier(&sc1200wdt_notifier);
450
451 out_io:
452         release_region(io, io_len);
453
454 out_pnp:
455 #if defined CONFIG_PNP
456         if (isapnp)
457                 pnp_unregister_driver(&scl200wdt_pnp_driver);
458 #endif
459         goto out_clean;
460 }
461
462
463 static void __exit sc1200wdt_exit(void)
464 {
465         misc_deregister(&sc1200wdt_miscdev);
466         unregister_reboot_notifier(&sc1200wdt_notifier);
467
468 #if defined CONFIG_PNP
469         if (isapnp)
470                 pnp_unregister_driver(&scl200wdt_pnp_driver);
471         else
472 #endif
473         release_region(io, io_len);
474 }
475
476 module_init(sc1200wdt_init);
477 module_exit(sc1200wdt_exit);
478
479 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
480 MODULE_DESCRIPTION("Driver for National Semiconductor PC87307/PC97307 watchdog component");
481 MODULE_LICENSE("GPL");
482 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);