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/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
  44 #include <asm/io.h>
  45 #include <asm/uaccess.h>
  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 static unsigned short zf_readb(unsigned char port)
  91 {
  92         outb(port, INDEX);
  93         return inb(DATA_B);
  94 }
  95
  96
  97 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
  98 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
  99 MODULE_LICENSE("GPL");
 100 MODULE_PARM(action, "i");
 101 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*)  1 = SMI  2 = NMI  3 = SCI");
 102
 103 #ifdef CONFIG_WATCHDOG_NOWAYOUT
 104 static int nowayout = 1;
 105 #else
 106 static int nowayout = 0;
 107 #endif
 108
 109 MODULE_PARM(nowayout,"i");
 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 static int zf_action = GEN_RESET;
 131 static int zf_is_open = 0;
 132 static int zf_expect_close = 0;
 133 static spinlock_t zf_lock;
 134 static spinlock_t zf_port_lock;
 135 static struct timer_list zf_timer;
 136 static unsigned long next_heartbeat = 0;
 137
 138
 139 /* timeout for user land heart beat (10 seconds) */
 140 #define ZF_USER_TIMEO (HZ*10)
 141
 142 /* timeout for hardware watchdog (~500ms) */
 143 #define ZF_HW_TIMEO (HZ/2)
 144
 145 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
 146 #define ZF_CTIMEOUT 0xffff
 147
 148 #ifndef ZF_DEBUG
 149 #       define dprintk(format, args...)
 150 #else
 151 #       define dprintk(format, args...) printk(KERN_DEBUG PFX; ":" __FUNCTION__ ":%d: " format, __LINE__ , ## args)
 152 #endif
 153
 154
 155 /* STATUS register functions */
 156
 157 static inline unsigned char zf_get_status(void)
 158 {
 159         return zf_readb(STATUS);
 160 }
 161
 162 static inline void zf_set_status(unsigned char new)
 163 {
 164         zf_writeb(STATUS, new);
 165 }
 166
 167
 168 /* CONTROL register functions */
 169
 170 static inline unsigned short zf_get_control(void)
 171 {
 172         return zf_readw(CONTROL);
 173 }
 174
 175 static inline void zf_set_control(unsigned short new)
 176 {
 177         zf_writew(CONTROL, new);
 178 }
 179
 180
 181 /* WD#? counter functions */
 182 /*
 183  *      Just get current counter value
 184  */
 185
 186 static inline unsigned short zf_get_timer(unsigned char n)
 187 {
 188         switch(n){
 189                 case WD1:
 190                         return zf_readw(COUNTER_1);
 191                 case WD2:
 192                         return zf_readb(COUNTER_2);
 193                 default:
 194                         return 0;
 195         }
 196 }
 197
 198 /*
 199  *      Just set counter value
 200  */
 201
 202 static inline void zf_set_timer(unsigned short new, unsigned char n)
 203 {
 204         switch(n){
 205                 case WD1:
 206                         zf_writew(COUNTER_1, new);
 207                 case WD2:
 208                         zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
 209                 default:
 210                         return;
 211         }
 212 }
 213
 214 /*
 215  * stop hardware timer
 216  */
 217 static void zf_timer_off(void)
 218 {
 219         unsigned int ctrl_reg = 0;
 220         unsigned long flags;
 221
 222         /* stop internal ping */
 223         del_timer_sync(&zf_timer);
 224
 225         spin_lock_irqsave(&zf_port_lock, flags);
 226         /* stop watchdog timer */
 227         ctrl_reg = zf_get_control();
 228         ctrl_reg |= (ENABLE_WD1|ENABLE_WD2);    /* disable wd1 and wd2 */
 229         ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
 230         zf_set_control(ctrl_reg);
 231         spin_unlock_irqrestore(&zf_port_lock, flags);
 232
 233         printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
 234 }
 235
 236
 237 /*
 238  * start hardware timer
 239  */
 240 static void zf_timer_on(void)
 241 {
 242         unsigned int ctrl_reg = 0;
 243         unsigned long flags;
 244
 245         spin_lock_irqsave(&zf_port_lock, flags);
 246
 247         zf_writeb(PULSE_LEN, 0xff);
 248
 249         zf_set_timer(ZF_CTIMEOUT, WD1);
 250
 251         /* user land ping */
 252         next_heartbeat = jiffies + ZF_USER_TIMEO;
 253
 254         /* start the timer for internal ping */
 255         zf_timer.expires = jiffies + ZF_HW_TIMEO;
 256
 257         add_timer(&zf_timer);
 258
 259         /* start watchdog timer */
 260         ctrl_reg = zf_get_control();
 261         ctrl_reg |= (ENABLE_WD1|zf_action);
 262         zf_set_control(ctrl_reg);
 263         spin_unlock_irqrestore(&zf_port_lock, flags);
 264
 265         printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
 266 }
 267
 268
 269 static void zf_ping(unsigned long data)
 270 {
 271         unsigned int ctrl_reg = 0;
 272         unsigned long flags;
 273
 274         zf_writeb(COUNTER_2, 0xff);
 275
 276         if(time_before(jiffies, next_heartbeat)){
 277
 278                 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
 279
 280                 /*
 281                  * reset event is activated by transition from 0 to 1 on
 282                  * RESET_WD1 bit and we assume that it is already zero...
 283                  */
 284
 285                 spin_lock_irqsave(&zf_port_lock, flags);
 286                 ctrl_reg = zf_get_control();
 287                 ctrl_reg |= RESET_WD1;
 288                 zf_set_control(ctrl_reg);
 289
 290                 /* ...and nothing changes until here */
 291                 ctrl_reg &= ~(RESET_WD1);
 292                 zf_set_control(ctrl_reg);
 293                 spin_unlock_irqrestore(&zf_port_lock, flags);
 294
 295                 zf_timer.expires = jiffies + ZF_HW_TIMEO;
 296                 add_timer(&zf_timer);
 297         }else{
 298                 printk(KERN_CRIT PFX ": I will reset your machine\n");
 299         }
 300 }
 301
 302 static ssize_t zf_write(struct file *file, const char *buf, size_t count,
 303                                                                 loff_t *ppos)
 304 {
 305         /*  Can't seek (pwrite) on this device  */
 306         if (ppos != &file->f_pos)
 307                 return -ESPIPE;
 308
 309         /* See if we got the magic character */
 310         if(count){
 311
 312                 /*
 313                  * no need to check for close confirmation
 314                  * no way to disable watchdog ;)
 315                  */
 316                 if (!nowayout) {
 317                         size_t ofs;
 318
 319                         /*
 320                          * note: just in case someone wrote the magic character
 321                          * five months ago...
 322                          */
 323                         zf_expect_close = 0;
 324
 325                         /* now scan */
 326                         for (ofs = 0; ofs != count; ofs++){
 327                                 char c;
 328                                 if (get_user(c, buf + ofs))
 329                                         return -EFAULT;
 330                                 if (c == 'V'){
 331                                         zf_expect_close = 1;
 332                                         dprintk("zf_expect_close 1\n");
 333                                 }
 334                         }
 335                 }
 336
 337                 /*
 338                  * Well, anyhow someone wrote to us,
 339                  * we should return that favour
 340                  */
 341                 next_heartbeat = jiffies + ZF_USER_TIMEO;
 342                 dprintk("user ping at %ld\n", jiffies);
 343
 344                 return 1;
 345         }
 346
 347         return 0;
 348 }
 349
 350 static ssize_t zf_read(struct file *file, char *buf, size_t count,
 351                                                         loff_t *ppos)
 352 {
 353         return -EINVAL;
 354 }
 355
 356
 357
 358 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 359         unsigned long arg)
 360 {
 361         switch(cmd){
 362                 case WDIOC_GETSUPPORT:
 363                         if (copy_to_user((struct watchdog_info *)arg,
 364                                          &zf_info, sizeof(zf_info)))
 365                                 return -EFAULT;
 366                         break;
 367
 368                 case WDIOC_GETSTATUS:
 369                         if (copy_to_user((int *)arg, &zf_is_open, sizeof(int)))
 370                                 return -EFAULT;
 371                         break;
 372
 373                 case WDIOC_KEEPALIVE:
 374                         zf_ping(0);
 375                         break;
 376
 377                 default:
 378                         return -ENOTTY;
 379         }
 380
 381         return 0;
 382 }
 383
 384 static int zf_open(struct inode *inode, struct file *file)
 385 {
 386         switch(minor(inode->i_rdev)){
 387                 case WATCHDOG_MINOR:
 388                         spin_lock(&zf_lock);
 389                         if(zf_is_open){
 390                                 spin_unlock(&zf_lock);
 391                                 return -EBUSY;
 392                         }
 393
 394                         if (nowayout)
 395                                 __module_get(THIS_MODULE);
 396
 397                         zf_is_open = 1;
 398
 399                         spin_unlock(&zf_lock);
 400
 401                         zf_timer_on();
 402
 403                         return 0;
 404                 default:
 405                         return -ENODEV;
 406         }
 407 }
 408
 409 static int zf_close(struct inode *inode, struct file *file)
 410 {
 411         if(minor(inode->i_rdev) == WATCHDOG_MINOR){
 412
 413                 if(zf_expect_close){
 414                         zf_timer_off();
 415                 } else {
 416                         del_timer(&zf_timer);
 417                         printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
 418                 }
 419
 420                 spin_lock(&zf_lock);
 421                 zf_is_open = 0;
 422                 spin_unlock(&zf_lock);
 423
 424                 zf_expect_close = 0;
 425         }
 426
 427         return 0;
 428 }
 429
 430 /*
 431  * Notifier for system down
 432  */
 433
 434 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
 435                                                                 void *unused)
 436 {
 437         if(code == SYS_DOWN || code == SYS_HALT){
 438                 zf_timer_off();
 439         }
 440
 441         return NOTIFY_DONE;
 442 }
 443
 444
 445
 446
 447 static struct file_operations zf_fops = {
 448         .owner          = THIS_MODULE,
 449         .read           = zf_read,
 450         .write          = zf_write,
 451         .ioctl          = zf_ioctl,
 452         .open           = zf_open,
 453         .release        = zf_close,
 454 };
 455
 456 static struct miscdevice zf_miscdev = {
 457         .minor = WATCHDOG_MINOR,
 458         .name = "watchdog",
 459         .fops = &zf_fops
 460 };
 461
 462
 463 /*
 464  * The device needs to learn about soft shutdowns in order to
 465  * turn the timebomb registers off.
 466  */
 467 static struct notifier_block zf_notifier = {
 468         .notifier_call = zf_notify_sys,
 469         .next = NULL,
 470         .priority = 0
 471 };
 472
 473 static void __init zf_show_action(int act)
 474 {
 475         char *str[] = { "RESET", "SMI", "NMI", "SCI" };
 476
 477         printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
 478 }
 479
 480 static int __init zf_init(void)
 481 {
 482         int ret;
 483
 484         printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
 485
 486         ret = zf_get_ZFL_version();
 487         printk("%#x\n", ret);
 488         if((!ret) || (ret != 0xffff)){
 489                 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
 490                 return -ENODEV;
 491         }
 492
 493         if((action <= 3) && (action >= 0)){
 494                 zf_action = zf_action>>action;
 495         } else
 496                 action = 0;
 497
 498         zf_show_action(action);
 499
 500         spin_lock_init(&zf_lock);
 501         spin_lock_init(&zf_port_lock);
 502
 503         ret = misc_register(&zf_miscdev);
 504         if (ret){
 505                 printk(KERN_ERR "can't misc_register on minor=%d\n",
 506                                                         WATCHDOG_MINOR);
 507                 goto out;
 508         }
 509
 510         if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
 511                 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
 512                                                         ZF_IOBASE);
 513                 ret = -EBUSY;
 514                 goto no_region;
 515         }
 516
 517         ret = register_reboot_notifier(&zf_notifier);
 518         if(ret){
 519                 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
 520                                                                         ret);
 521                 goto no_reboot;
 522         }
 523
 524         zf_set_status(0);
 525         zf_set_control(0);
 526
 527         /* this is the timer that will do the hard work */
 528         init_timer(&zf_timer);
 529         zf_timer.function = zf_ping;
 530         zf_timer.data = 0;
 531
 532         return 0;
 533
 534 no_reboot:
 535         release_region(ZF_IOBASE, 3);
 536 no_region:
 537         misc_deregister(&zf_miscdev);
 538 out:
 539         return ret;
 540 }
 541
 542
 543 void __exit zf_exit(void)
 544 {
 545         zf_timer_off();
 546
 547         misc_deregister(&zf_miscdev);
 548         unregister_reboot_notifier(&zf_notifier);
 549         release_region(ZF_IOBASE, 3);
 550 }
 551
 552 module_init(zf_init);
 553 module_exit(zf_exit);