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pc87413_wdt.c
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1 /*
2  * NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
3  *
4  * This code is based on wdt.c with original copyright.
5  *
6  * (C) Copyright 2006 Sven Anders, <[email protected]>
7  * and Marcus Junker, <[email protected]>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * as published by the Free Software Foundation; either version
12  * 2 of the License, or (at your option) any later version.
13  *
14  * Neither Sven Anders, Marcus Junker nor ANDURAS AG
15  * admit liability nor provide warranty for any of this software.
16  * This material is provided "AS-IS" and at no charge.
17  *
18  * Release 1.1
19  */
20 
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 
23 #include <linux/module.h>
24 #include <linux/types.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
27 #include <linux/ioport.h>
28 #include <linux/delay.h>
29 #include <linux/notifier.h>
30 #include <linux/fs.h>
31 #include <linux/reboot.h>
32 #include <linux/init.h>
33 #include <linux/spinlock.h>
34 #include <linux/moduleparam.h>
35 #include <linux/io.h>
36 #include <linux/uaccess.h>
37 
38 
39 /* #define DEBUG 1 */
40 
41 #define DEFAULT_TIMEOUT 1 /* 1 minute */
42 #define MAX_TIMEOUT 255
43 
44 #define VERSION "1.1"
45 #define MODNAME "pc87413 WDT"
46 #define DPFX MODNAME " - DEBUG: "
47 
48 #define WDT_INDEX_IO_PORT (io+0) /* I/O port base (index register) */
49 #define WDT_DATA_IO_PORT (WDT_INDEX_IO_PORT+1)
50 #define SWC_LDN 0x04
51 #define SIOCFG2 0x22 /* Serial IO register */
52 #define WDCTL 0x10 /* Watchdog-Timer-Control-Register */
53 #define WDTO 0x11 /* Watchdog timeout register */
54 #define WDCFG 0x12 /* Watchdog config register */
55 
56 #define IO_DEFAULT 0x2E /* Address used on Portwell Boards */
57 
58 static int io = IO_DEFAULT;
59 static int swc_base_addr = -1;
60 
61 static int timeout = DEFAULT_TIMEOUT; /* timeout value */
62 static unsigned long timer_enabled; /* is the timer enabled? */
63 
64 static char expect_close; /* is the close expected? */
65 
66 static DEFINE_SPINLOCK(io_lock); /* to guard us from io races */
67 
68 static bool nowayout = WATCHDOG_NOWAYOUT;
69 
70 /* -- Low level function ----------------------------------------*/
71 
72 /* Select pins for Watchdog output */
73 
74 static inline void pc87413_select_wdt_out(void)
75 {
76  unsigned int cr_data = 0;
77 
78  /* Step 1: Select multiple pin,pin55,as WDT output */
79 
81 
82  cr_data = inb(WDT_DATA_IO_PORT);
83 
84  cr_data |= 0x80; /* Set Bit7 to 1*/
86 
87  outb_p(cr_data, WDT_DATA_IO_PORT);
88 
89 #ifdef DEBUG
91  "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
92  cr_data);
93 #endif
94 }
95 
96 /* Enable SWC functions */
97 
98 static inline void pc87413_enable_swc(void)
99 {
100  unsigned int cr_data = 0;
101 
102  /* Step 2: Enable SWC functions */
103 
104  outb_p(0x07, WDT_INDEX_IO_PORT); /* Point SWC_LDN (LDN=4) */
106 
107  outb_p(0x30, WDT_INDEX_IO_PORT); /* Read Index 0x30 First */
108  cr_data = inb(WDT_DATA_IO_PORT);
109  cr_data |= 0x01; /* Set Bit0 to 1 */
110  outb_p(0x30, WDT_INDEX_IO_PORT);
111  outb_p(cr_data, WDT_DATA_IO_PORT); /* Index0x30_bit0P1 */
112 
113 #ifdef DEBUG
114  pr_info(DPFX "pc87413 - Enable SWC functions\n");
115 #endif
116 }
117 
118 /* Read SWC I/O base address */
119 
120 static void pc87413_get_swc_base_addr(void)
121 {
122  unsigned char addr_l, addr_h = 0;
123 
124  /* Step 3: Read SWC I/O Base Address */
125 
126  outb_p(0x60, WDT_INDEX_IO_PORT); /* Read Index 0x60 */
127  addr_h = inb(WDT_DATA_IO_PORT);
128 
129  outb_p(0x61, WDT_INDEX_IO_PORT); /* Read Index 0x61 */
130 
131  addr_l = inb(WDT_DATA_IO_PORT);
132 
133  swc_base_addr = (addr_h << 8) + addr_l;
134 #ifdef DEBUG
135  pr_info(DPFX
136  "Read SWC I/O Base Address: low %d, high %d, res %d\n",
137  addr_l, addr_h, swc_base_addr);
138 #endif
139 }
140 
141 /* Select Bank 3 of SWC */
142 
143 static inline void pc87413_swc_bank3(void)
144 {
145  /* Step 4: Select Bank3 of SWC */
146  outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
147 #ifdef DEBUG
148  pr_info(DPFX "Select Bank3 of SWC\n");
149 #endif
150 }
151 
152 /* Set watchdog timeout to x minutes */
153 
154 static inline void pc87413_programm_wdto(char pc87413_time)
155 {
156  /* Step 5: Programm WDTO, Twd. */
157  outb_p(pc87413_time, swc_base_addr + WDTO);
158 #ifdef DEBUG
159  pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
160 #endif
161 }
162 
163 /* Enable WDEN */
164 
165 static inline void pc87413_enable_wden(void)
166 {
167  /* Step 6: Enable WDEN */
168  outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
169 #ifdef DEBUG
170  pr_info(DPFX "Enable WDEN\n");
171 #endif
172 }
173 
174 /* Enable SW_WD_TREN */
175 static inline void pc87413_enable_sw_wd_tren(void)
176 {
177  /* Enable SW_WD_TREN */
178  outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
179 #ifdef DEBUG
180  pr_info(DPFX "Enable SW_WD_TREN\n");
181 #endif
182 }
183 
184 /* Disable SW_WD_TREN */
185 
186 static inline void pc87413_disable_sw_wd_tren(void)
187 {
188  /* Disable SW_WD_TREN */
189  outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
190 #ifdef DEBUG
191  pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
192 #endif
193 }
194 
195 /* Enable SW_WD_TRG */
196 
197 static inline void pc87413_enable_sw_wd_trg(void)
198 {
199  /* Enable SW_WD_TRG */
200  outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
201 #ifdef DEBUG
202  pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
203 #endif
204 }
205 
206 /* Disable SW_WD_TRG */
207 
208 static inline void pc87413_disable_sw_wd_trg(void)
209 {
210  /* Disable SW_WD_TRG */
211  outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
212 #ifdef DEBUG
213  pr_info(DPFX "Disable SW_WD_TRG\n");
214 #endif
215 }
216 
217 /* -- Higher level functions ------------------------------------*/
218 
219 /* Enable the watchdog */
220 
221 static void pc87413_enable(void)
222 {
223  spin_lock(&io_lock);
224 
225  pc87413_swc_bank3();
226  pc87413_programm_wdto(timeout);
227  pc87413_enable_wden();
228  pc87413_enable_sw_wd_tren();
229  pc87413_enable_sw_wd_trg();
230 
231  spin_unlock(&io_lock);
232 }
233 
234 /* Disable the watchdog */
235 
236 static void pc87413_disable(void)
237 {
238  spin_lock(&io_lock);
239 
240  pc87413_swc_bank3();
241  pc87413_disable_sw_wd_tren();
242  pc87413_disable_sw_wd_trg();
243  pc87413_programm_wdto(0);
244 
245  spin_unlock(&io_lock);
246 }
247 
248 /* Refresh the watchdog */
249 
250 static void pc87413_refresh(void)
251 {
252  spin_lock(&io_lock);
253 
254  pc87413_swc_bank3();
255  pc87413_disable_sw_wd_tren();
256  pc87413_disable_sw_wd_trg();
257  pc87413_programm_wdto(timeout);
258  pc87413_enable_wden();
259  pc87413_enable_sw_wd_tren();
260  pc87413_enable_sw_wd_trg();
261 
262  spin_unlock(&io_lock);
263 }
264 
265 /* -- File operations -------------------------------------------*/
266 
274 static int pc87413_open(struct inode *inode, struct file *file)
275 {
276  /* /dev/watchdog can only be opened once */
277 
278  if (test_and_set_bit(0, &timer_enabled))
279  return -EBUSY;
280 
281  if (nowayout)
282  __module_get(THIS_MODULE);
283 
284  /* Reload and activate timer */
285  pc87413_refresh();
286 
287  pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
288 
289  return nonseekable_open(inode, file);
290 }
291 
304 static int pc87413_release(struct inode *inode, struct file *file)
305 {
306  /* Shut off the timer. */
307 
308  if (expect_close == 42) {
309  pc87413_disable();
310  pr_info("Watchdog disabled, sleeping again...\n");
311  } else {
312  pr_crit("Unexpected close, not stopping watchdog!\n");
313  pc87413_refresh();
314  }
315  clear_bit(0, &timer_enabled);
316  expect_close = 0;
317  return 0;
318 }
319 
327 static int pc87413_status(void)
328 {
329  return 0; /* currently not supported */
330 }
331 
343 static ssize_t pc87413_write(struct file *file, const char __user *data,
344  size_t len, loff_t *ppos)
345 {
346  /* See if we got the magic character 'V' and reload the timer */
347  if (len) {
348  if (!nowayout) {
349  size_t i;
350 
351  /* reset expect flag */
352  expect_close = 0;
353 
354  /* scan to see whether or not we got the
355  magic character */
356  for (i = 0; i != len; i++) {
357  char c;
358  if (get_user(c, data + i))
359  return -EFAULT;
360  if (c == 'V')
361  expect_close = 42;
362  }
363  }
364 
365  /* someone wrote to us, we should reload the timer */
366  pc87413_refresh();
367  }
368  return len;
369 }
370 
382 static long pc87413_ioctl(struct file *file, unsigned int cmd,
383  unsigned long arg)
384 {
385  int new_timeout;
386 
387  union {
388  struct watchdog_info __user *ident;
389  int __user *i;
390  } uarg;
391 
392  static const struct watchdog_info ident = {
393  .options = WDIOF_KEEPALIVEPING |
396  .firmware_version = 1,
397  .identity = "PC87413(HF/F) watchdog",
398  };
399 
400  uarg.i = (int __user *)arg;
401 
402  switch (cmd) {
403  case WDIOC_GETSUPPORT:
404  return copy_to_user(uarg.ident, &ident,
405  sizeof(ident)) ? -EFAULT : 0;
406  case WDIOC_GETSTATUS:
407  return put_user(pc87413_status(), uarg.i);
408  case WDIOC_GETBOOTSTATUS:
409  return put_user(0, uarg.i);
410  case WDIOC_SETOPTIONS:
411  {
412  int options, retval = -EINVAL;
413  if (get_user(options, uarg.i))
414  return -EFAULT;
415  if (options & WDIOS_DISABLECARD) {
416  pc87413_disable();
417  retval = 0;
418  }
419  if (options & WDIOS_ENABLECARD) {
420  pc87413_enable();
421  retval = 0;
422  }
423  return retval;
424  }
425  case WDIOC_KEEPALIVE:
426  pc87413_refresh();
427 #ifdef DEBUG
428  pr_info(DPFX "keepalive\n");
429 #endif
430  return 0;
431  case WDIOC_SETTIMEOUT:
432  if (get_user(new_timeout, uarg.i))
433  return -EFAULT;
434  /* the API states this is given in secs */
435  new_timeout /= 60;
436  if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
437  return -EINVAL;
438  timeout = new_timeout;
439  pc87413_refresh();
440  /* fall through and return the new timeout... */
441  case WDIOC_GETTIMEOUT:
442  new_timeout = timeout * 60;
443  return put_user(new_timeout, uarg.i);
444  default:
445  return -ENOTTY;
446  }
447 }
448 
449 /* -- Notifier funtions -----------------------------------------*/
450 
463 static int pc87413_notify_sys(struct notifier_block *this,
464  unsigned long code,
465  void *unused)
466 {
467  if (code == SYS_DOWN || code == SYS_HALT)
468  /* Turn the card off */
469  pc87413_disable();
470  return NOTIFY_DONE;
471 }
472 
473 /* -- Module's structures ---------------------------------------*/
474 
475 static const struct file_operations pc87413_fops = {
476  .owner = THIS_MODULE,
477  .llseek = no_llseek,
478  .write = pc87413_write,
479  .unlocked_ioctl = pc87413_ioctl,
480  .open = pc87413_open,
481  .release = pc87413_release,
482 };
483 
484 static struct notifier_block pc87413_notifier = {
485  .notifier_call = pc87413_notify_sys,
486 };
487 
488 static struct miscdevice pc87413_miscdev = {
490  .name = "watchdog",
491  .fops = &pc87413_fops,
492 };
493 
494 /* -- Module init functions -------------------------------------*/
495 
504 static int __init pc87413_init(void)
505 {
506  int ret;
507 
508  pr_info("Version " VERSION " at io 0x%X\n",
510 
511  if (!request_muxed_region(io, 2, MODNAME))
512  return -EBUSY;
513 
514  ret = register_reboot_notifier(&pc87413_notifier);
515  if (ret != 0) {
516  pr_err("cannot register reboot notifier (err=%d)\n", ret);
517  }
518 
519  ret = misc_register(&pc87413_miscdev);
520  if (ret != 0) {
521  pr_err("cannot register miscdev on minor=%d (err=%d)\n",
522  WATCHDOG_MINOR, ret);
523  goto reboot_unreg;
524  }
525  pr_info("initialized. timeout=%d min\n", timeout);
526 
527  pc87413_select_wdt_out();
528  pc87413_enable_swc();
529  pc87413_get_swc_base_addr();
530 
531  if (!request_region(swc_base_addr, 0x20, MODNAME)) {
532  pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
533  ret = -EBUSY;
534  goto misc_unreg;
535  }
536 
537  pc87413_enable();
538 
539  release_region(io, 2);
540  return 0;
541 
542 misc_unreg:
543  misc_deregister(&pc87413_miscdev);
544 reboot_unreg:
545  unregister_reboot_notifier(&pc87413_notifier);
546  release_region(io, 2);
547  return ret;
548 }
549 
560 static void __exit pc87413_exit(void)
561 {
562  /* Stop the timer before we leave */
563  if (!nowayout) {
564  pc87413_disable();
565  pr_info("Watchdog disabled\n");
566  }
567 
568  misc_deregister(&pc87413_miscdev);
569  unregister_reboot_notifier(&pc87413_notifier);
570  release_region(swc_base_addr, 0x20);
571 
572  pr_info("watchdog component driver removed\n");
573 }
574 
575 module_init(pc87413_init);
576 module_exit(pc87413_exit);
577 
578 MODULE_AUTHOR("Sven Anders <[email protected]>, "
579  "Marcus Junker <[email protected]>,");
580 MODULE_DESCRIPTION("PC87413 WDT driver");
581 MODULE_LICENSE("GPL");
582 
584 
585 module_param(io, int, 0);
586 MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
588 
589 module_param(timeout, int, 0);
590 MODULE_PARM_DESC(timeout,
591  "Watchdog timeout in minutes (default="
593 
594 module_param(nowayout, bool, 0);
595 MODULE_PARM_DESC(nowayout,
596  "Watchdog cannot be stopped once started (default="
598