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Linux/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 #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(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 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 */
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         pr_info("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                 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 
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 
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 
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, &reg);
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 struct pnp_device_id scl200wdt_pnp_devices[] = {
346         /* National Semiconductor PC87307/PC97307 watchdog component */
347         {.id = "NSC0800", .driver_data = 0},
348         {.id = ""},
349 };
350 
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 
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 
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 
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 

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