drivers/watchdog/w83697ug_wdt.c

   1 /*
   2  *      w83697ug/uf WDT driver
   3  *
   4  *      (c) Copyright 2008 Flemming Fransen <ff@nrvissing.net>
   5  *              reused original code to support w83697ug/uf.
   6  *
   7  *      Based on w83627hf_wdt.c which is based on advantechwdt.c
   8  *      which is based on wdt.c.
   9  *      Original copyright messages:
  10  *
  11  *      (c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
  12  *              added support for W83627THF.
  13  *
  14  *      (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
  15  *
  16  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
  17  *
  18  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  19  *                              http://www.redhat.com
  20  *
  21  *      This program is free software; you can redistribute it and/or
  22  *      modify it under the terms of the GNU General Public License
  23  *      as published by the Free Software Foundation; either version
  24  *      2 of the License, or (at your option) any later version.
  25  *
  26  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  27  *      warranty for any of this software. This material is provided
  28  *      "AS-IS" and at no charge.
  29  *
  30  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  31  */
  32
  33 #include <linux/module.h>
  34 #include <linux/moduleparam.h>
  35 #include <linux/types.h>
  36 #include <linux/miscdevice.h>
  37 #include <linux/watchdog.h>
  38 #include <linux/fs.h>
  39 #include <linux/ioport.h>
  40 #include <linux/notifier.h>
  41 #include <linux/reboot.h>
  42 #include <linux/init.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/io.h>
  45 #include <linux/uaccess.h>
  46
  47 #include <asm/system.h>
  48
  49 #define WATCHDOG_NAME "w83697ug/uf WDT"
  50 #define PFX WATCHDOG_NAME ": "
  51 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  52
  53 static unsigned long wdt_is_open;
  54 static char expect_close;
  55 static DEFINE_SPINLOCK(io_lock);
  56
  57 static int wdt_io = 0x2e;
  58 module_param(wdt_io, int, 0);
  59 MODULE_PARM_DESC(wdt_io, "w83697ug/uf WDT io port (default 0x2e)");
  60
  61 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  62 module_param(timeout, int, 0);
  63 MODULE_PARM_DESC(timeout,
  64         "Watchdog timeout in seconds. 1<= timeout <=255 (default="
  65                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  66
  67 static int nowayout = WATCHDOG_NOWAYOUT;
  68 module_param(nowayout, int, 0);
  69 MODULE_PARM_DESC(nowayout,
  70         "Watchdog cannot be stopped once started (default="
  71                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  72
  73 /*
  74  *      Kernel methods.
  75  */
  76
  77 #define WDT_EFER (wdt_io+0)   /* Extended Function Enable Registers */
  78 #define WDT_EFIR (wdt_io+0)   /* Extended Function Index Register
  79                                                         (same as EFER) */
  80 #define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
  81
  82 static int w83697ug_select_wd_register(void)
  83 {
  84         unsigned char c;
  85         unsigned char version;
  86
  87         outb_p(0x87, WDT_EFER); /* Enter extended function mode */
  88         outb_p(0x87, WDT_EFER); /* Again according to manual */
  89
  90         outb(0x20, WDT_EFER);   /* check chip version   */
  91         version = inb(WDT_EFDR);
  92
  93         if (version == 0x68) {  /* W83697UG             */
  94                 printk(KERN_INFO PFX "Watchdog chip version 0x%02x = "
  95                         "W83697UG/UF found at 0x%04x\n", version, wdt_io);
  96
  97                 outb_p(0x2b, WDT_EFER);
  98                 c = inb_p(WDT_EFDR);    /* select WDT0 */
  99                 c &= ~0x04;
 100                 outb_p(0x2b, WDT_EFER);
 101                 outb_p(c, WDT_EFDR);    /* set pin118 to WDT0 */
 102
 103         } else {
 104                 printk(KERN_ERR PFX "No W83697UG/UF could be found\n");
 105                 return -ENODEV;
 106         }
 107
 108         outb_p(0x07, WDT_EFER); /* point to logical device number reg */
 109         outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
 110         outb_p(0x30, WDT_EFER); /* select CR30 */
 111         c = inb_p(WDT_EFDR);
 112         outb_p(c || 0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
 113
 114         return 0;
 115 }
 116
 117 static void w83697ug_unselect_wd_register(void)
 118 {
 119         outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
 120 }
 121
 122 static int w83697ug_init(void)
 123 {
 124         int ret;
 125         unsigned char t;
 126
 127         ret = w83697ug_select_wd_register();
 128         if (ret != 0)
 129                 return ret;
 130
 131         outb_p(0xF6, WDT_EFER); /* Select CRF6 */
 132         t = inb_p(WDT_EFDR);    /* read CRF6 */
 133         if (t != 0) {
 134                 printk(KERN_INFO PFX "Watchdog already running."
 135                         " Resetting timeout to %d sec\n", timeout);
 136                 outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
 137         }
 138         outb_p(0xF5, WDT_EFER); /* Select CRF5 */
 139         t = inb_p(WDT_EFDR);    /* read CRF5 */
 140         t &= ~0x0C;             /* set second mode &
 141                                         disable keyboard turning off watchdog */
 142         outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
 143
 144         w83697ug_unselect_wd_register();
 145         return 0;
 146 }
 147
 148 static void wdt_ctrl(int timeout)
 149 {
 150         spin_lock(&io_lock);
 151
 152         if (w83697ug_select_wd_register() < 0)
 153                 return;
 154
 155         outb_p(0xF4, WDT_EFER);    /* Select CRF4 */
 156         outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
 157
 158         w83697ug_unselect_wd_register();
 159
 160         spin_unlock(&io_lock);
 161 }
 162
 163 static int wdt_ping(void)
 164 {
 165         wdt_ctrl(timeout);
 166         return 0;
 167 }
 168
 169 static int wdt_disable(void)
 170 {
 171         wdt_ctrl(0);
 172         return 0;
 173 }
 174
 175 static int wdt_set_heartbeat(int t)
 176 {
 177         if (t < 1 || t > 255)
 178                 return -EINVAL;
 179
 180         timeout = t;
 181         return 0;
 182 }
 183
 184 static ssize_t wdt_write(struct file *file, const char __user *buf,
 185                                                 size_t count, loff_t *ppos)
 186 {
 187         if (count) {
 188                 if (!nowayout) {
 189                         size_t i;
 190
 191                         expect_close = 0;
 192
 193                         for (i = 0; i != count; i++) {
 194                                 char c;
 195                                 if (get_user(c, buf + i))
 196                                         return -EFAULT;
 197                                 if (c == 'V')
 198                                         expect_close = 42;
 199                         }
 200                 }
 201                 wdt_ping();
 202         }
 203         return count;
 204 }
 205
 206 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 207 {
 208         void __user *argp = (void __user *)arg;
 209         int __user *p = argp;
 210         int new_timeout;
 211         static const struct watchdog_info ident = {
 212                 .options =              WDIOF_KEEPALIVEPING |
 213                                         WDIOF_SETTIMEOUT |
 214                                         WDIOF_MAGICCLOSE,
 215                 .firmware_version =     1,
 216                 .identity =             "W83697UG WDT",
 217         };
 218
 219         switch (cmd) {
 220         case WDIOC_GETSUPPORT:
 221                 if (copy_to_user(argp, &ident, sizeof(ident)))
 222                         return -EFAULT;
 223                 break;
 224
 225         case WDIOC_GETSTATUS:
 226         case WDIOC_GETBOOTSTATUS:
 227                 return put_user(0, p);
 228
 229         case WDIOC_SETOPTIONS:
 230         {
 231                 int options, retval = -EINVAL;
 232
 233                 if (get_user(options, p))
 234                         return -EFAULT;
 235
 236                 if (options & WDIOS_DISABLECARD) {
 237                         wdt_disable();
 238                         retval = 0;
 239                 }
 240
 241                 if (options & WDIOS_ENABLECARD) {
 242                         wdt_ping();
 243                         retval = 0;
 244                 }
 245
 246                 return retval;
 247         }
 248
 249         case WDIOC_KEEPALIVE:
 250                 wdt_ping();
 251                 break;
 252
 253         case WDIOC_SETTIMEOUT:
 254                 if (get_user(new_timeout, p))
 255                         return -EFAULT;
 256                 if (wdt_set_heartbeat(new_timeout))
 257                         return -EINVAL;
 258                 wdt_ping();
 259                 /* Fall */
 260
 261         case WDIOC_GETTIMEOUT:
 262                 return put_user(timeout, p);
 263
 264         default:
 265                 return -ENOTTY;
 266         }
 267         return 0;
 268 }
 269
 270 static int wdt_open(struct inode *inode, struct file *file)
 271 {
 272         if (test_and_set_bit(0, &wdt_is_open))
 273                 return -EBUSY;
 274         /*
 275          *      Activate
 276          */
 277
 278         wdt_ping();
 279         return nonseekable_open(inode, file);
 280 }
 281
 282 static int wdt_close(struct inode *inode, struct file *file)
 283 {
 284         if (expect_close == 42)
 285                 wdt_disable();
 286         else {
 287                 printk(KERN_CRIT PFX
 288                         "Unexpected close, not stopping watchdog!\n");
 289                 wdt_ping();
 290         }
 291         expect_close = 0;
 292         clear_bit(0, &wdt_is_open);
 293         return 0;
 294 }
 295
 296 /*
 297  *      Notifier for system down
 298  */
 299
 300 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 301         void *unused)
 302 {
 303         if (code == SYS_DOWN || code == SYS_HALT)
 304                 wdt_disable();  /* Turn the WDT off */
 305
 306         return NOTIFY_DONE;
 307 }
 308
 309 /*
 310  *      Kernel Interfaces
 311  */
 312
 313 static const struct file_operations wdt_fops = {
 314         .owner          = THIS_MODULE,
 315         .llseek         = no_llseek,
 316         .write          = wdt_write,
 317         .unlocked_ioctl = wdt_ioctl,
 318         .open           = wdt_open,
 319         .release        = wdt_close,
 320 };
 321
 322 static struct miscdevice wdt_miscdev = {
 323         .minor = WATCHDOG_MINOR,
 324         .name = "watchdog",
 325         .fops = &wdt_fops,
 326 };
 327
 328 /*
 329  *      The WDT needs to learn about soft shutdowns in order to
 330  *      turn the timebomb registers off.
 331  */
 332
 333 static struct notifier_block wdt_notifier = {
 334         .notifier_call = wdt_notify_sys,
 335 };
 336
 337 static int __init wdt_init(void)
 338 {
 339         int ret;
 340
 341         printk(KERN_INFO "WDT driver for the Winbond(TM) W83697UG/UF Super I/O chip initialising.\n");
 342
 343         if (wdt_set_heartbeat(timeout)) {
 344                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 345                 printk(KERN_INFO PFX
 346                         "timeout value must be 1<=timeout<=255, using %d\n",
 347                         WATCHDOG_TIMEOUT);
 348         }
 349
 350         if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
 351                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 352                         wdt_io);
 353                 ret = -EIO;
 354                 goto out;
 355         }
 356
 357         ret = w83697ug_init();
 358         if (ret != 0)
 359                 goto unreg_regions;
 360
 361         ret = register_reboot_notifier(&wdt_notifier);
 362         if (ret != 0) {
 363                 printk(KERN_ERR PFX
 364                         "cannot register reboot notifier (err=%d)\n", ret);
 365                 goto unreg_regions;
 366         }
 367
 368         ret = misc_register(&wdt_miscdev);
 369         if (ret != 0) {
 370                 printk(KERN_ERR PFX
 371                         "cannot register miscdev on minor=%d (err=%d)\n",
 372                         WATCHDOG_MINOR, ret);
 373                 goto unreg_reboot;
 374         }
 375
 376         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 377                 timeout, nowayout);
 378
 379 out:
 380         return ret;
 381 unreg_reboot:
 382         unregister_reboot_notifier(&wdt_notifier);
 383 unreg_regions:
 384         release_region(wdt_io, 1);
 385         goto out;
 386 }
 387
 388 static void __exit wdt_exit(void)
 389 {
 390         misc_deregister(&wdt_miscdev);
 391         unregister_reboot_notifier(&wdt_notifier);
 392         release_region(wdt_io, 1);
 393 }
 394
 395 module_init(wdt_init);
 396 module_exit(wdt_exit);
 397
 398 MODULE_LICENSE("GPL");
 399 MODULE_AUTHOR("Flemming Frandsen <ff@nrvissing.net>");
 400 MODULE_DESCRIPTION("w83697ug/uf WDT driver");
 401 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);