drivers/char/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/config.h>
  32 #include <linux/module.h>
  33 #include <linux/moduleparam.h>
  34 #include <linux/types.h>
  35 #include <linux/timer.h>
  36 #include <linux/jiffies.h>
  37 #include <linux/miscdevice.h>
  38 #include <linux/watchdog.h>
  39 #include <linux/fs.h>
  40 #include <linux/ioport.h>
  41 #include <linux/notifier.h>
  42 #include <linux/reboot.h>
  43 #include <linux/init.h>
  44
  45 #include <asm/io.h>
  46 #include <asm/uaccess.h>
  47 #include <asm/system.h>
  48
  49 /* ports */
  50 #define ZF_IOBASE       0x218
  51 #define INDEX           0x218
  52 #define DATA_B          0x219
  53 #define DATA_W          0x21A
  54 #define DATA_D          0x21A
  55
  56 /* indexes */                   /* size */
  57 #define ZFL_VERSION     0x02    /* 16   */
  58 #define CONTROL         0x10    /* 16   */
  59 #define STATUS          0x12    /* 8    */
  60 #define COUNTER_1       0x0C    /* 16   */
  61 #define COUNTER_2       0x0E    /* 8    */
  62 #define PULSE_LEN       0x0F    /* 8    */
  63
  64 /* controls */
  65 #define ENABLE_WD1      0x0001
  66 #define ENABLE_WD2      0x0002
  67 #define RESET_WD1       0x0010
  68 #define RESET_WD2       0x0020
  69 #define GEN_SCI         0x0100
  70 #define GEN_NMI         0x0200
  71 #define GEN_SMI         0x0400
  72 #define GEN_RESET       0x0800
  73
  74
  75 /* utilities */
  76
  77 #define WD1     0
  78 #define WD2     1
  79
  80 #define zf_writew(port, data)  { outb(port, INDEX); outw(data, DATA_W); }
  81 #define zf_writeb(port, data)  { outb(port, INDEX); outb(data, DATA_B); }
  82 #define zf_get_ZFL_version()   zf_readw(ZFL_VERSION)
  83
  84
  85 static unsigned short zf_readw(unsigned char port)
  86 {
  87         outb(port, INDEX);
  88         return inw(DATA_W);
  89 }
  90
  91 static unsigned short zf_readb(unsigned char port)
  92 {
  93         outb(port, INDEX);
  94         return inb(DATA_B);
  95 }
  96
  97
  98 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
  99 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
 100 MODULE_LICENSE("GPL");
 101 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 102
 103 #ifdef CONFIG_WATCHDOG_NOWAYOUT
 104 static int nowayout = 1;
 105 #else
 106 static int nowayout = 0;
 107 #endif
 108
 109 module_param(nowayout, int, 0);
 110 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
 111
 112 #define PFX "machzwd"
 113
 114 static struct watchdog_info zf_info = {
 115         .options                = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 116         .firmware_version       = 1,
 117         .identity               = "ZF-Logic watchdog",
 118 };
 119
 120
 121 /*
 122  * action refers to action taken when watchdog resets
 123  * 0 = GEN_RESET
 124  * 1 = GEN_SMI
 125  * 2 = GEN_NMI
 126  * 3 = GEN_SCI
 127  * defaults to GEN_RESET (0)
 128  */
 129 static int action = 0;
 130 module_param(action, int, 0);
 131 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*)  1 = SMI  2 = NMI  3 = SCI");
 132
 133 static int zf_action = GEN_RESET;
 134 static unsigned long zf_is_open;
 135 static char zf_expect_close;
 136 static spinlock_t zf_lock;
 137 static spinlock_t zf_port_lock;
 138 static struct timer_list zf_timer;
 139 static unsigned long next_heartbeat = 0;
 140
 141
 142 /* timeout for user land heart beat (10 seconds) */
 143 #define ZF_USER_TIMEO (HZ*10)
 144
 145 /* timeout for hardware watchdog (~500ms) */
 146 #define ZF_HW_TIMEO (HZ/2)
 147
 148 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
 149 #define ZF_CTIMEOUT 0xffff
 150
 151 #ifndef ZF_DEBUG
 152 #       define dprintk(format, args...)
 153 #else
 154 #       define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args)
 155 #endif
 156
 157
 158 /* STATUS register functions */
 159
 160 static inline unsigned char zf_get_status(void)
 161 {
 162         return zf_readb(STATUS);
 163 }
 164
 165 static inline void zf_set_status(unsigned char new)
 166 {
 167         zf_writeb(STATUS, new);
 168 }
 169
 170
 171 /* CONTROL register functions */
 172
 173 static inline unsigned short zf_get_control(void)
 174 {
 175         return zf_readw(CONTROL);
 176 }
 177
 178 static inline void zf_set_control(unsigned short new)
 179 {
 180         zf_writew(CONTROL, new);
 181 }
 182
 183
 184 /* WD#? counter functions */
 185 /*
 186  *      Just get current counter value
 187  */
 188
 189 static inline unsigned short zf_get_timer(unsigned char n)
 190 {
 191         switch(n){
 192                 case WD1:
 193                         return zf_readw(COUNTER_1);
 194                 case WD2:
 195                         return zf_readb(COUNTER_2);
 196                 default:
 197                         return 0;
 198         }
 199 }
 200
 201 /*
 202  *      Just set counter value
 203  */
 204
 205 static inline void zf_set_timer(unsigned short new, unsigned char n)
 206 {
 207         switch(n){
 208                 case WD1:
 209                         zf_writew(COUNTER_1, new);
 210                 case WD2:
 211                         zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
 212                 default:
 213                         return;
 214         }
 215 }
 216
 217 /*
 218  * stop hardware timer
 219  */
 220 static void zf_timer_off(void)
 221 {
 222         unsigned int ctrl_reg = 0;
 223         unsigned long flags;
 224
 225         /* stop internal ping */
 226         del_timer_sync(&zf_timer);
 227
 228         spin_lock_irqsave(&zf_port_lock, flags);
 229         /* stop watchdog timer */
 230         ctrl_reg = zf_get_control();
 231         ctrl_reg |= (ENABLE_WD1|ENABLE_WD2);    /* disable wd1 and wd2 */
 232         ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
 233         zf_set_control(ctrl_reg);
 234         spin_unlock_irqrestore(&zf_port_lock, flags);
 235
 236         printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
 237 }
 238
 239
 240 /*
 241  * start hardware timer
 242  */
 243 static void zf_timer_on(void)
 244 {
 245         unsigned int ctrl_reg = 0;
 246         unsigned long flags;
 247
 248         spin_lock_irqsave(&zf_port_lock, flags);
 249
 250         zf_writeb(PULSE_LEN, 0xff);
 251
 252         zf_set_timer(ZF_CTIMEOUT, WD1);
 253
 254         /* user land ping */
 255         next_heartbeat = jiffies + ZF_USER_TIMEO;
 256
 257         /* start the timer for internal ping */
 258         zf_timer.expires = jiffies + ZF_HW_TIMEO;
 259
 260         add_timer(&zf_timer);
 261
 262         /* start watchdog timer */
 263         ctrl_reg = zf_get_control();
 264         ctrl_reg |= (ENABLE_WD1|zf_action);
 265         zf_set_control(ctrl_reg);
 266         spin_unlock_irqrestore(&zf_port_lock, flags);
 267
 268         printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
 269 }
 270
 271
 272 static void zf_ping(unsigned long data)
 273 {
 274         unsigned int ctrl_reg = 0;
 275         unsigned long flags;
 276
 277         zf_writeb(COUNTER_2, 0xff);
 278
 279         if(time_before(jiffies, next_heartbeat)){
 280
 281                 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
 282
 283                 /*
 284                  * reset event is activated by transition from 0 to 1 on
 285                  * RESET_WD1 bit and we assume that it is already zero...
 286                  */
 287
 288                 spin_lock_irqsave(&zf_port_lock, flags);
 289                 ctrl_reg = zf_get_control();
 290                 ctrl_reg |= RESET_WD1;
 291                 zf_set_control(ctrl_reg);
 292
 293                 /* ...and nothing changes until here */
 294                 ctrl_reg &= ~(RESET_WD1);
 295                 zf_set_control(ctrl_reg);
 296                 spin_unlock_irqrestore(&zf_port_lock, flags);
 297
 298                 zf_timer.expires = jiffies + ZF_HW_TIMEO;
 299                 add_timer(&zf_timer);
 300         }else{
 301                 printk(KERN_CRIT PFX ": I will reset your machine\n");
 302         }
 303 }
 304
 305 static ssize_t zf_write(struct file *file, const char *buf, size_t count,
 306                                                                 loff_t *ppos)
 307 {
 308         /*  Can't seek (pwrite) on this device  */
 309         if (ppos != &file->f_pos)
 310                 return -ESPIPE;
 311
 312         /* See if we got the magic character */
 313         if(count){
 314
 315                 /*
 316                  * no need to check for close confirmation
 317                  * no way to disable watchdog ;)
 318                  */
 319                 if (!nowayout) {
 320                         size_t ofs;
 321
 322                         /*
 323                          * note: just in case someone wrote the magic character
 324                          * five months ago...
 325                          */
 326                         zf_expect_close = 0;
 327
 328                         /* now scan */
 329                         for (ofs = 0; ofs != count; ofs++){
 330                                 char c;
 331                                 if (get_user(c, buf + ofs))
 332                                         return -EFAULT;
 333                                 if (c == 'V'){
 334                                         zf_expect_close = 42;
 335                                         dprintk("zf_expect_close = 42\n");
 336                                 }
 337                         }
 338                 }
 339
 340                 /*
 341                  * Well, anyhow someone wrote to us,
 342                  * we should return that favour
 343                  */
 344                 next_heartbeat = jiffies + ZF_USER_TIMEO;
 345                 dprintk("user ping at %ld\n", jiffies);
 346
 347         }
 348
 349         return count;
 350 }
 351
 352 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 353         unsigned long arg)
 354 {
 355         switch(cmd){
 356                 case WDIOC_GETSUPPORT:
 357                         if (copy_to_user((struct watchdog_info *)arg,
 358                                          &zf_info, sizeof(zf_info)))
 359                                 return -EFAULT;
 360                         break;
 361
 362                 case WDIOC_GETSTATUS:
 363                         return put_user(0, (int *) arg);
 364
 365                 case WDIOC_KEEPALIVE:
 366                         zf_ping(0);
 367                         break;
 368
 369                 default:
 370                         return -ENOIOCTLCMD;
 371         }
 372
 373         return 0;
 374 }
 375
 376 static int zf_open(struct inode *inode, struct file *file)
 377 {
 378         spin_lock(&zf_lock);
 379         if(test_and_set_bit(0, &zf_is_open)) {
 380                 spin_unlock(&zf_lock);
 381                 return -EBUSY;
 382         }
 383
 384         if (nowayout)
 385                 __module_get(THIS_MODULE);
 386
 387         spin_unlock(&zf_lock);
 388
 389         zf_timer_on();
 390
 391         return 0;
 392 }
 393
 394 static int zf_close(struct inode *inode, struct file *file)
 395 {
 396         if(zf_expect_close == 42){
 397                 zf_timer_off();
 398         } else {
 399                 del_timer(&zf_timer);
 400                 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
 401         }
 402
 403         spin_lock(&zf_lock);
 404         clear_bit(0, &zf_is_open);
 405         spin_unlock(&zf_lock);
 406
 407         zf_expect_close = 0;
 408
 409         return 0;
 410 }
 411
 412 /*
 413  * Notifier for system down
 414  */
 415
 416 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
 417                                                                 void *unused)
 418 {
 419         if(code == SYS_DOWN || code == SYS_HALT){
 420                 zf_timer_off();
 421         }
 422
 423         return NOTIFY_DONE;
 424 }
 425
 426
 427
 428
 429 static struct file_operations zf_fops = {
 430         .owner          = THIS_MODULE,
 431         .write          = zf_write,
 432         .ioctl          = zf_ioctl,
 433         .open           = zf_open,
 434         .release        = zf_close,
 435 };
 436
 437 static struct miscdevice zf_miscdev = {
 438         .minor = WATCHDOG_MINOR,
 439         .name = "watchdog",
 440         .fops = &zf_fops,
 441 };
 442
 443
 444 /*
 445  * The device needs to learn about soft shutdowns in order to
 446  * turn the timebomb registers off.
 447  */
 448 static struct notifier_block zf_notifier = {
 449         .notifier_call = zf_notify_sys,
 450 };
 451
 452 static void __init zf_show_action(int act)
 453 {
 454         char *str[] = { "RESET", "SMI", "NMI", "SCI" };
 455
 456         printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
 457 }
 458
 459 static int __init zf_init(void)
 460 {
 461         int ret;
 462
 463         printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
 464
 465         ret = zf_get_ZFL_version();
 466         printk("%#x\n", ret);
 467         if((!ret) || (ret != 0xffff)){
 468                 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
 469                 return -ENODEV;
 470         }
 471
 472         if((action <= 3) && (action >= 0)){
 473                 zf_action = zf_action>>action;
 474         } else
 475                 action = 0;
 476
 477         zf_show_action(action);
 478
 479         spin_lock_init(&zf_lock);
 480         spin_lock_init(&zf_port_lock);
 481
 482         ret = misc_register(&zf_miscdev);
 483         if (ret){
 484                 printk(KERN_ERR "can't misc_register on minor=%d\n",
 485                                                         WATCHDOG_MINOR);
 486                 goto out;
 487         }
 488
 489         if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
 490                 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
 491                                                         ZF_IOBASE);
 492                 ret = -EBUSY;
 493                 goto no_region;
 494         }
 495
 496         ret = register_reboot_notifier(&zf_notifier);
 497         if(ret){
 498                 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
 499                                                                         ret);
 500                 goto no_reboot;
 501         }
 502
 503         zf_set_status(0);
 504         zf_set_control(0);
 505
 506         /* this is the timer that will do the hard work */
 507         init_timer(&zf_timer);
 508         zf_timer.function = zf_ping;
 509         zf_timer.data = 0;
 510
 511         return 0;
 512
 513 no_reboot:
 514         release_region(ZF_IOBASE, 3);
 515 no_region:
 516         misc_deregister(&zf_miscdev);
 517 out:
 518         return ret;
 519 }
 520
 521
 522 void __exit zf_exit(void)
 523 {
 524         zf_timer_off();
 525
 526         misc_deregister(&zf_miscdev);
 527         unregister_reboot_notifier(&zf_notifier);
 528         release_region(ZF_IOBASE, 3);
 529 }
 530
 531 module_init(zf_init);
 532 module_exit(zf_exit);