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