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 supoprt 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 void 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;
 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
 115 static void w83697ug_unselect_wd_register(void)
 116 {
 117         outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
 118 }
 119
 120 static void w83697ug_init(void)
 121 {
 122         unsigned char t;
 123
 124         w83697ug_select_wd_register();
 125
 126         outb_p(0xF6, WDT_EFER); /* Select CRF6 */
 127         t = inb_p(WDT_EFDR);    /* read CRF6 */
 128         if (t != 0) {
 129                 printk(KERN_INFO PFX "Watchdog already running."
 130                         " Resetting timeout to %d sec\n", timeout);
 131                 outb_p(timeout, WDT_EFDR);    /* Write back to CRF6 */
 132         }
 133         outb_p(0xF5, WDT_EFER); /* Select CRF5 */
 134         t = inb_p(WDT_EFDR);    /* read CRF5 */
 135         t &= ~0x0C;             /* set second mode &
 136                                         disable keyboard turning off watchdog */
 137         outb_p(t, WDT_EFDR);    /* Write back to CRF5 */
 138
 139         w83697ug_unselect_wd_register();
 140 }
 141
 142 static void wdt_ctrl(int timeout)
 143 {
 144         spin_lock(&io_lock);
 145
 146         w83697ug_select_wd_register();
 147
 148         outb_p(0xF4, WDT_EFER);    /* Select CRF4 */
 149         outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
 150
 151         w83697ug_unselect_wd_register();
 152
 153         spin_unlock(&io_lock);
 154 }
 155
 156 static int wdt_ping(void)
 157 {
 158         wdt_ctrl(timeout);
 159         return 0;
 160 }
 161
 162 static int wdt_disable(void)
 163 {
 164         wdt_ctrl(0);
 165         return 0;
 166 }
 167
 168 static int wdt_set_heartbeat(int t)
 169 {
 170         if (t < 1 || t > 255)
 171                 return -EINVAL;
 172
 173         timeout = t;
 174         return 0;
 175 }
 176
 177 static ssize_t wdt_write(struct file *file, const char __user *buf,
 178                                                 size_t count, loff_t *ppos)
 179 {
 180         if (count) {
 181                 if (!nowayout) {
 182                         size_t i;
 183
 184                         expect_close = 0;
 185
 186                         for (i = 0; i != count; i++) {
 187                                 char c;
 188                                 if (get_user(c, buf + i))
 189                                         return -EFAULT;
 190                                 if (c == 'V')
 191                                         expect_close = 42;
 192                         }
 193                 }
 194                 wdt_ping();
 195         }
 196         return count;
 197 }
 198
 199 static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 200 {
 201         void __user *argp = (void __user *)arg;
 202         int __user *p = argp;
 203         int new_timeout;
 204         static const struct watchdog_info ident = {
 205                 .options =              WDIOF_KEEPALIVEPING |
 206                                         WDIOF_SETTIMEOUT |
 207                                         WDIOF_MAGICCLOSE,
 208                 .firmware_version =     1,
 209                 .identity =             "W83697UG WDT",
 210         };
 211
 212         switch (cmd) {
 213         case WDIOC_GETSUPPORT:
 214                 if (copy_to_user(argp, &ident, sizeof(ident)))
 215                         return -EFAULT;
 216                 break;
 217
 218         case WDIOC_GETSTATUS:
 219         case WDIOC_GETBOOTSTATUS:
 220                 return put_user(0, p);
 221
 222         case WDIOC_SETOPTIONS:
 223         {
 224                 int options, retval = -EINVAL;
 225
 226                 if (get_user(options, p))
 227                         return -EFAULT;
 228
 229                 if (options & WDIOS_DISABLECARD) {
 230                         wdt_disable();
 231                         retval = 0;
 232                 }
 233
 234                 if (options & WDIOS_ENABLECARD) {
 235                         wdt_ping();
 236                         retval = 0;
 237                 }
 238
 239                 return retval;
 240         }
 241
 242         case WDIOC_KEEPALIVE:
 243                 wdt_ping();
 244                 break;
 245
 246         case WDIOC_SETTIMEOUT:
 247                 if (get_user(new_timeout, p))
 248                         return -EFAULT;
 249                 if (wdt_set_heartbeat(new_timeout))
 250                         return -EINVAL;
 251                 wdt_ping();
 252                 /* Fall */
 253
 254         case WDIOC_GETTIMEOUT:
 255                 return put_user(timeout, p);
 256
 257         default:
 258                 return -ENOTTY;
 259         }
 260         return 0;
 261 }
 262
 263 static int wdt_open(struct inode *inode, struct file *file)
 264 {
 265         if (test_and_set_bit(0, &wdt_is_open))
 266                 return -EBUSY;
 267         /*
 268          *      Activate
 269          */
 270
 271         wdt_ping();
 272         return nonseekable_open(inode, file);
 273 }
 274
 275 static int wdt_close(struct inode *inode, struct file *file)
 276 {
 277         if (expect_close == 42)
 278                 wdt_disable();
 279         else {
 280                 printk(KERN_CRIT PFX
 281                         "Unexpected close, not stopping watchdog!\n");
 282                 wdt_ping();
 283         }
 284         expect_close = 0;
 285         clear_bit(0, &wdt_is_open);
 286         return 0;
 287 }
 288
 289 /*
 290  *      Notifier for system down
 291  */
 292
 293 static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
 294         void *unused)
 295 {
 296         if (code == SYS_DOWN || code == SYS_HALT)
 297                 wdt_disable();  /* Turn the WDT off */
 298
 299         return NOTIFY_DONE;
 300 }
 301
 302 /*
 303  *      Kernel Interfaces
 304  */
 305
 306 static const struct file_operations wdt_fops = {
 307         .owner          = THIS_MODULE,
 308         .llseek         = no_llseek,
 309         .write          = wdt_write,
 310         .unlocked_ioctl = wdt_ioctl,
 311         .open           = wdt_open,
 312         .release        = wdt_close,
 313 };
 314
 315 static struct miscdevice wdt_miscdev = {
 316         .minor = WATCHDOG_MINOR,
 317         .name = "watchdog",
 318         .fops = &wdt_fops,
 319 };
 320
 321 /*
 322  *      The WDT needs to learn about soft shutdowns in order to
 323  *      turn the timebomb registers off.
 324  */
 325
 326 static struct notifier_block wdt_notifier = {
 327         .notifier_call = wdt_notify_sys,
 328 };
 329
 330 static int __init wdt_init(void)
 331 {
 332         int ret;
 333
 334         printk(KERN_INFO "WDT driver for the Winbond(TM) W83697UG/UF Super I/O chip initialising.\n");
 335
 336         if (wdt_set_heartbeat(timeout)) {
 337                 wdt_set_heartbeat(WATCHDOG_TIMEOUT);
 338                 printk(KERN_INFO PFX
 339                         "timeout value must be 1<=timeout<=255, using %d\n",
 340                         WATCHDOG_TIMEOUT);
 341         }
 342
 343         if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
 344                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 345                         wdt_io);
 346                 ret = -EIO;
 347                 goto out;
 348         }
 349
 350         w83697ug_init();
 351
 352         ret = register_reboot_notifier(&wdt_notifier);
 353         if (ret != 0) {
 354                 printk(KERN_ERR PFX
 355                         "cannot register reboot notifier (err=%d)\n", ret);
 356                 goto unreg_regions;
 357         }
 358
 359         ret = misc_register(&wdt_miscdev);
 360         if (ret != 0) {
 361                 printk(KERN_ERR PFX
 362                         "cannot register miscdev on minor=%d (err=%d)\n",
 363                         WATCHDOG_MINOR, ret);
 364                 goto unreg_reboot;
 365         }
 366
 367         printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 368                 timeout, nowayout);
 369
 370 out:
 371         return ret;
 372 unreg_reboot:
 373         unregister_reboot_notifier(&wdt_notifier);
 374 unreg_regions:
 375         release_region(wdt_io, 1);
 376         goto out;
 377 }
 378
 379 static void __exit wdt_exit(void)
 380 {
 381         misc_deregister(&wdt_miscdev);
 382         unregister_reboot_notifier(&wdt_notifier);
 383         release_region(wdt_io, 1);
 384 }
 385
 386 module_init(wdt_init);
 387 module_exit(wdt_exit);
 388
 389 MODULE_LICENSE("GPL");
 390 MODULE_AUTHOR("Flemming Frandsen <ff@nrvissing.net>");
 391 MODULE_DESCRIPTION("w83697ug/uf WDT driver");
 392 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);