drivers/watchdog/machzwd.c

   1 /*
   2  *  MachZ ZF-Logic Watchdog Timer driver for Linux
   3  *
   4  *
   5  *  This program is free software; you can redistribute it and/or
   6  *  modify it under the terms of the GNU General Public License
   7  *  as published by the Free Software Foundation; either version
   8  *  2 of the License, or (at your option) any later version.
   9  *
  10  *  The author does NOT admit liability nor provide warranty for
  11  *  any of this software. This material is provided "AS-IS" in
  12  *  the hope that it may be useful for others.
  13  *
  14  *  Author: Fernando Fuganti <fuganti@conectiva.com.br>
  15  *
  16  *  Based on sbc60xxwdt.c by Jakob Oestergaard
  17  *
  18  *
  19  *  We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
  20  *  following periods:
  21  *      wd#1 - 2 seconds;
  22  *      wd#2 - 7.2 ms;
  23  *  After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
  24  *  a system RESET and it starts wd#2 that unconditionaly will RESET
  25  *  the system when the counter reaches zero.
  26  *
  27  *  14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  28  *      Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  29  */
  30
  31 #include <linux/module.h>
  32 #include <linux/moduleparam.h>
  33 #include <linux/types.h>
  34 #include <linux/timer.h>
  35 #include <linux/jiffies.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/io.h>
  44 #include <linux/uaccess.h>
  45
  46 #include <asm/system.h>
  47
  48 /* ports */
  49 #define ZF_IOBASE       0x218
  50 #define INDEX           0x218
  51 #define DATA_B          0x219
  52 #define DATA_W          0x21A
  53 #define DATA_D          0x21A
  54
  55 /* indexes */                   /* size */
  56 #define ZFL_VERSION     0x02    /* 16   */
  57 #define CONTROL         0x10    /* 16   */
  58 #define STATUS          0x12    /* 8    */
  59 #define COUNTER_1       0x0C    /* 16   */
  60 #define COUNTER_2       0x0E    /* 8    */
  61 #define PULSE_LEN       0x0F    /* 8    */
  62
  63 /* controls */
  64 #define ENABLE_WD1      0x0001
  65 #define ENABLE_WD2      0x0002
  66 #define RESET_WD1       0x0010
  67 #define RESET_WD2       0x0020
  68 #define GEN_SCI         0x0100
  69 #define GEN_NMI         0x0200
  70 #define GEN_SMI         0x0400
  71 #define GEN_RESET       0x0800
  72
  73
  74 /* utilities */
  75
  76 #define WD1     0
  77 #define WD2     1
  78
  79 #define zf_writew(port, data)  { outb(port, INDEX); outw(data, DATA_W); }
  80 #define zf_writeb(port, data)  { outb(port, INDEX); outb(data, DATA_B); }
  81 #define zf_get_ZFL_version()   zf_readw(ZFL_VERSION)
  82
  83
  84 static unsigned short zf_readw(unsigned char port)
  85 {
  86         outb(port, INDEX);
  87         return inw(DATA_W);
  88 }
  89
  90
  91 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
  92 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
  93 MODULE_LICENSE("GPL");
  94 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
  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 #define PFX "machzwd"
 103
 104 static struct watchdog_info zf_info = {
 105         .options                = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 106         .firmware_version       = 1,
 107         .identity               = "ZF-Logic watchdog",
 108 };
 109
 110
 111 /*
 112  * action refers to action taken when watchdog resets
 113  * 0 = GEN_RESET
 114  * 1 = GEN_SMI
 115  * 2 = GEN_NMI
 116  * 3 = GEN_SCI
 117  * defaults to GEN_RESET (0)
 118  */
 119 static int action;
 120 module_param(action, int, 0);
 121 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*)  1 = SMI  2 = NMI  3 = SCI");
 122
 123 static void zf_ping(unsigned long data);
 124
 125 static int zf_action = GEN_RESET;
 126 static unsigned long zf_is_open;
 127 static char zf_expect_close;
 128 static DEFINE_SPINLOCK(zf_port_lock);
 129 static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
 130 static unsigned long next_heartbeat;
 131
 132
 133 /* timeout for user land heart beat (10 seconds) */
 134 #define ZF_USER_TIMEO (HZ*10)
 135
 136 /* timeout for hardware watchdog (~500ms) */
 137 #define ZF_HW_TIMEO (HZ/2)
 138
 139 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
 140 #define ZF_CTIMEOUT 0xffff
 141
 142 #ifndef ZF_DEBUG
 143 #       define dprintk(format, args...)
 144 #else
 145 #       define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __func__, __LINE__ , ## args)
 146 #endif
 147
 148
 149 static inline void zf_set_status(unsigned char new)
 150 {
 151         zf_writeb(STATUS, new);
 152 }
 153
 154
 155 /* CONTROL register functions */
 156
 157 static inline unsigned short zf_get_control(void)
 158 {
 159         return zf_readw(CONTROL);
 160 }
 161
 162 static inline void zf_set_control(unsigned short new)
 163 {
 164         zf_writew(CONTROL, new);
 165 }
 166
 167
 168 /* WD#? counter functions */
 169 /*
 170  *      Just set counter value
 171  */
 172
 173 static inline void zf_set_timer(unsigned short new, unsigned char n)
 174 {
 175         switch (n) {
 176         case WD1:
 177                 zf_writew(COUNTER_1, new);
 178         case WD2:
 179                 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
 180         default:
 181                 return;
 182         }
 183 }
 184
 185 /*
 186  * stop hardware timer
 187  */
 188 static void zf_timer_off(void)
 189 {
 190         unsigned int ctrl_reg = 0;
 191         unsigned long flags;
 192
 193         /* stop internal ping */
 194         del_timer_sync(&zf_timer);
 195
 196         spin_lock_irqsave(&zf_port_lock, flags);
 197         /* stop watchdog timer */
 198         ctrl_reg = zf_get_control();
 199         ctrl_reg |= (ENABLE_WD1|ENABLE_WD2);    /* disable wd1 and wd2 */
 200         ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
 201         zf_set_control(ctrl_reg);
 202         spin_unlock_irqrestore(&zf_port_lock, flags);
 203
 204         printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
 205 }
 206
 207
 208 /*
 209  * start hardware timer
 210  */
 211 static void zf_timer_on(void)
 212 {
 213         unsigned int ctrl_reg = 0;
 214         unsigned long flags;
 215
 216         spin_lock_irqsave(&zf_port_lock, flags);
 217
 218         zf_writeb(PULSE_LEN, 0xff);
 219
 220         zf_set_timer(ZF_CTIMEOUT, WD1);
 221
 222         /* user land ping */
 223         next_heartbeat = jiffies + ZF_USER_TIMEO;
 224
 225         /* start the timer for internal ping */
 226         mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
 227
 228         /* start watchdog timer */
 229         ctrl_reg = zf_get_control();
 230         ctrl_reg |= (ENABLE_WD1|zf_action);
 231         zf_set_control(ctrl_reg);
 232         spin_unlock_irqrestore(&zf_port_lock, flags);
 233
 234         printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
 235 }
 236
 237
 238 static void zf_ping(unsigned long data)
 239 {
 240         unsigned int ctrl_reg = 0;
 241         unsigned long flags;
 242
 243         zf_writeb(COUNTER_2, 0xff);
 244
 245         if (time_before(jiffies, next_heartbeat)) {
 246                 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
 247                 /*
 248                  * reset event is activated by transition from 0 to 1 on
 249                  * RESET_WD1 bit and we assume that it is already zero...
 250                  */
 251
 252                 spin_lock_irqsave(&zf_port_lock, flags);
 253                 ctrl_reg = zf_get_control();
 254                 ctrl_reg |= RESET_WD1;
 255                 zf_set_control(ctrl_reg);
 256
 257                 /* ...and nothing changes until here */
 258                 ctrl_reg &= ~(RESET_WD1);
 259                 zf_set_control(ctrl_reg);
 260                 spin_unlock_irqrestore(&zf_port_lock, flags);
 261
 262                 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
 263         } else
 264                 printk(KERN_CRIT PFX ": I will reset your machine\n");
 265 }
 266
 267 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
 268                                                                 loff_t *ppos)
 269 {
 270         /* See if we got the magic character */
 271         if (count) {
 272                 /*
 273                  * no need to check for close confirmation
 274                  * no way to disable watchdog ;)
 275                  */
 276                 if (!nowayout) {
 277                         size_t ofs;
 278                         /*
 279                          * note: just in case someone wrote the magic character
 280                          * five months ago...
 281                          */
 282                         zf_expect_close = 0;
 283
 284                         /* now scan */
 285                         for (ofs = 0; ofs != count; ofs++) {
 286                                 char c;
 287                                 if (get_user(c, buf + ofs))
 288                                         return -EFAULT;
 289                                 if (c == 'V') {
 290                                         zf_expect_close = 42;
 291                                         dprintk("zf_expect_close = 42\n");
 292                                 }
 293                         }
 294                 }
 295
 296                 /*
 297                  * Well, anyhow someone wrote to us,
 298                  * we should return that favour
 299                  */
 300                 next_heartbeat = jiffies + ZF_USER_TIMEO;
 301                 dprintk("user ping at %ld\n", jiffies);
 302         }
 303         return count;
 304 }
 305
 306 static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 307 {
 308         void __user *argp = (void __user *)arg;
 309         int __user *p = argp;
 310         switch (cmd) {
 311         case WDIOC_GETSUPPORT:
 312                 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
 313                         return -EFAULT;
 314                 break;
 315         case WDIOC_GETSTATUS:
 316         case WDIOC_GETBOOTSTATUS:
 317                 return put_user(0, p);
 318         case WDIOC_KEEPALIVE:
 319                 zf_ping(0);
 320                 break;
 321         default:
 322                 return -ENOTTY;
 323         }
 324         return 0;
 325 }
 326
 327 static int zf_open(struct inode *inode, struct file *file)
 328 {
 329         if (test_and_set_bit(0, &zf_is_open))
 330                 return -EBUSY;
 331         if (nowayout)
 332                 __module_get(THIS_MODULE);
 333         zf_timer_on();
 334         return nonseekable_open(inode, file);
 335 }
 336
 337 static int zf_close(struct inode *inode, struct file *file)
 338 {
 339         if (zf_expect_close == 42)
 340                 zf_timer_off();
 341         else {
 342                 del_timer(&zf_timer);
 343                 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
 344         }
 345         clear_bit(0, &zf_is_open);
 346         zf_expect_close = 0;
 347         return 0;
 348 }
 349
 350 /*
 351  * Notifier for system down
 352  */
 353
 354 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
 355                                                                 void *unused)
 356 {
 357         if (code == SYS_DOWN || code == SYS_HALT)
 358                 zf_timer_off();
 359         return NOTIFY_DONE;
 360 }
 361
 362 static const struct file_operations zf_fops = {
 363         .owner          = THIS_MODULE,
 364         .llseek         = no_llseek,
 365         .write          = zf_write,
 366         .unlocked_ioctl = zf_ioctl,
 367         .open           = zf_open,
 368         .release        = zf_close,
 369 };
 370
 371 static struct miscdevice zf_miscdev = {
 372         .minor = WATCHDOG_MINOR,
 373         .name = "watchdog",
 374         .fops = &zf_fops,
 375 };
 376
 377
 378 /*
 379  * The device needs to learn about soft shutdowns in order to
 380  * turn the timebomb registers off.
 381  */
 382 static struct notifier_block zf_notifier = {
 383         .notifier_call = zf_notify_sys,
 384 };
 385
 386 static void __init zf_show_action(int act)
 387 {
 388         char *str[] = { "RESET", "SMI", "NMI", "SCI" };
 389
 390         printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
 391 }
 392
 393 static int __init zf_init(void)
 394 {
 395         int ret;
 396
 397         printk(KERN_INFO PFX
 398                 ": MachZ ZF-Logic Watchdog driver initializing.\n");
 399
 400         ret = zf_get_ZFL_version();
 401         if (!ret || ret == 0xffff) {
 402                 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
 403                 return -ENODEV;
 404         }
 405
 406         if (action <= 3 && action >= 0)
 407                 zf_action = zf_action >> action;
 408         else
 409                 action = 0;
 410
 411         zf_show_action(action);
 412
 413         if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
 414                 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
 415                                                         ZF_IOBASE);
 416                 ret = -EBUSY;
 417                 goto no_region;
 418         }
 419
 420         ret = register_reboot_notifier(&zf_notifier);
 421         if (ret) {
 422                 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
 423                                                                         ret);
 424                 goto no_reboot;
 425         }
 426
 427         ret = misc_register(&zf_miscdev);
 428         if (ret) {
 429                 printk(KERN_ERR "can't misc_register on minor=%d\n",
 430                                                         WATCHDOG_MINOR);
 431                 goto no_misc;
 432         }
 433
 434         zf_set_status(0);
 435         zf_set_control(0);
 436
 437         return 0;
 438
 439 no_misc:
 440         unregister_reboot_notifier(&zf_notifier);
 441 no_reboot:
 442         release_region(ZF_IOBASE, 3);
 443 no_region:
 444         return ret;
 445 }
 446
 447
 448 static void __exit zf_exit(void)
 449 {
 450         zf_timer_off();
 451
 452         misc_deregister(&zf_miscdev);
 453         unregister_reboot_notifier(&zf_notifier);
 454         release_region(ZF_IOBASE, 3);
 455 }
 456
 457 module_init(zf_init);
 458 module_exit(zf_exit);