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
  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
  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, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  99
 100 #define PFX "machzwd"
 101
 102 static struct watchdog_info zf_info = {
 103         .options                = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 104         .firmware_version       = 1,
 105         .identity               = "ZF-Logic watchdog",
 106 };
 107
 108
 109 /*
 110  * action refers to action taken when watchdog resets
 111  * 0 = GEN_RESET
 112  * 1 = GEN_SMI
 113  * 2 = GEN_NMI
 114  * 3 = GEN_SCI
 115  * defaults to GEN_RESET (0)
 116  */
 117 static int action = 0;
 118 module_param(action, int, 0);
 119 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*)  1 = SMI  2 = NMI  3 = SCI");
 120
 121 static void zf_ping(unsigned long data);
 122
 123 static int zf_action = GEN_RESET;
 124 static unsigned long zf_is_open;
 125 static char zf_expect_close;
 126 static DEFINE_SPINLOCK(zf_lock);
 127 static DEFINE_SPINLOCK(zf_port_lock);
 128 static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
 129 static unsigned long next_heartbeat = 0;
 130
 131
 132 /* timeout for user land heart beat (10 seconds) */
 133 #define ZF_USER_TIMEO (HZ*10)
 134
 135 /* timeout for hardware watchdog (~500ms) */
 136 #define ZF_HW_TIMEO (HZ/2)
 137
 138 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
 139 #define ZF_CTIMEOUT 0xffff
 140
 141 #ifndef ZF_DEBUG
 142 #       define dprintk(format, args...)
 143 #else
 144 <<<<<<< HEAD:drivers/watchdog/machzwd.c
 145 #       define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args)
 146 =======
 147 #       define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __func__, __LINE__ , ## args)
 148 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:drivers/watchdog/machzwd.c
 149 #endif
 150
 151
 152 static inline void zf_set_status(unsigned char new)
 153 {
 154         zf_writeb(STATUS, new);
 155 }
 156
 157
 158 /* CONTROL register functions */
 159
 160 static inline unsigned short zf_get_control(void)
 161 {
 162         return zf_readw(CONTROL);
 163 }
 164
 165 static inline void zf_set_control(unsigned short new)
 166 {
 167         zf_writew(CONTROL, new);
 168 }
 169
 170
 171 /* WD#? counter functions */
 172 /*
 173  *      Just set counter value
 174  */
 175
 176 static inline void zf_set_timer(unsigned short new, unsigned char n)
 177 {
 178         switch(n){
 179                 case WD1:
 180                         zf_writew(COUNTER_1, new);
 181                 case WD2:
 182                         zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
 183                 default:
 184                         return;
 185         }
 186 }
 187
 188 /*
 189  * stop hardware timer
 190  */
 191 static void zf_timer_off(void)
 192 {
 193         unsigned int ctrl_reg = 0;
 194         unsigned long flags;
 195
 196         /* stop internal ping */
 197         del_timer_sync(&zf_timer);
 198
 199         spin_lock_irqsave(&zf_port_lock, flags);
 200         /* stop watchdog timer */
 201         ctrl_reg = zf_get_control();
 202         ctrl_reg |= (ENABLE_WD1|ENABLE_WD2);    /* disable wd1 and wd2 */
 203         ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
 204         zf_set_control(ctrl_reg);
 205         spin_unlock_irqrestore(&zf_port_lock, flags);
 206
 207         printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
 208 }
 209
 210
 211 /*
 212  * start hardware timer
 213  */
 214 static void zf_timer_on(void)
 215 {
 216         unsigned int ctrl_reg = 0;
 217         unsigned long flags;
 218
 219         spin_lock_irqsave(&zf_port_lock, flags);
 220
 221         zf_writeb(PULSE_LEN, 0xff);
 222
 223         zf_set_timer(ZF_CTIMEOUT, WD1);
 224
 225         /* user land ping */
 226         next_heartbeat = jiffies + ZF_USER_TIMEO;
 227
 228         /* start the timer for internal ping */
 229         mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
 230
 231         /* start watchdog timer */
 232         ctrl_reg = zf_get_control();
 233         ctrl_reg |= (ENABLE_WD1|zf_action);
 234         zf_set_control(ctrl_reg);
 235         spin_unlock_irqrestore(&zf_port_lock, flags);
 236
 237         printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
 238 }
 239
 240
 241 static void zf_ping(unsigned long data)
 242 {
 243         unsigned int ctrl_reg = 0;
 244         unsigned long flags;
 245
 246         zf_writeb(COUNTER_2, 0xff);
 247
 248         if(time_before(jiffies, next_heartbeat)){
 249
 250                 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
 251
 252                 /*
 253                  * reset event is activated by transition from 0 to 1 on
 254                  * RESET_WD1 bit and we assume that it is already zero...
 255                  */
 256
 257                 spin_lock_irqsave(&zf_port_lock, flags);
 258                 ctrl_reg = zf_get_control();
 259                 ctrl_reg |= RESET_WD1;
 260                 zf_set_control(ctrl_reg);
 261
 262                 /* ...and nothing changes until here */
 263                 ctrl_reg &= ~(RESET_WD1);
 264                 zf_set_control(ctrl_reg);
 265                 spin_unlock_irqrestore(&zf_port_lock, flags);
 266
 267                 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
 268         }else{
 269                 printk(KERN_CRIT PFX ": I will reset your machine\n");
 270         }
 271 }
 272
 273 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
 274                                                                 loff_t *ppos)
 275 {
 276         /* See if we got the magic character */
 277         if(count){
 278
 279                 /*
 280                  * no need to check for close confirmation
 281                  * no way to disable watchdog ;)
 282                  */
 283                 if (!nowayout) {
 284                         size_t ofs;
 285
 286                         /*
 287                          * note: just in case someone wrote the magic character
 288                          * five months ago...
 289                          */
 290                         zf_expect_close = 0;
 291
 292                         /* now scan */
 293                         for (ofs = 0; ofs != count; ofs++){
 294                                 char c;
 295                                 if (get_user(c, buf + ofs))
 296                                         return -EFAULT;
 297                                 if (c == 'V'){
 298                                         zf_expect_close = 42;
 299                                         dprintk("zf_expect_close = 42\n");
 300                                 }
 301                         }
 302                 }
 303
 304                 /*
 305                  * Well, anyhow someone wrote to us,
 306                  * we should return that favour
 307                  */
 308                 next_heartbeat = jiffies + ZF_USER_TIMEO;
 309                 dprintk("user ping at %ld\n", jiffies);
 310
 311         }
 312
 313         return count;
 314 }
 315
 316 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 317         unsigned long arg)
 318 {
 319         void __user *argp = (void __user *)arg;
 320         int __user *p = argp;
 321         switch (cmd) {
 322         case WDIOC_GETSUPPORT:
 323                 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
 324                         return -EFAULT;
 325                 break;
 326
 327         case WDIOC_GETSTATUS:
 328         case WDIOC_GETBOOTSTATUS:
 329                 return put_user(0, p);
 330
 331         case WDIOC_KEEPALIVE:
 332                 zf_ping(0);
 333                 break;
 334
 335         default:
 336                 return -ENOTTY;
 337         }
 338
 339         return 0;
 340 }
 341
 342 static int zf_open(struct inode *inode, struct file *file)
 343 {
 344         spin_lock(&zf_lock);
 345         if(test_and_set_bit(0, &zf_is_open)) {
 346                 spin_unlock(&zf_lock);
 347                 return -EBUSY;
 348         }
 349
 350         if (nowayout)
 351                 __module_get(THIS_MODULE);
 352
 353         spin_unlock(&zf_lock);
 354
 355         zf_timer_on();
 356
 357         return nonseekable_open(inode, file);
 358 }
 359
 360 static int zf_close(struct inode *inode, struct file *file)
 361 {
 362         if(zf_expect_close == 42){
 363                 zf_timer_off();
 364         } else {
 365                 del_timer(&zf_timer);
 366                 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
 367         }
 368
 369         spin_lock(&zf_lock);
 370         clear_bit(0, &zf_is_open);
 371         spin_unlock(&zf_lock);
 372
 373         zf_expect_close = 0;
 374
 375         return 0;
 376 }
 377
 378 /*
 379  * Notifier for system down
 380  */
 381
 382 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
 383                                                                 void *unused)
 384 {
 385         if(code == SYS_DOWN || code == SYS_HALT){
 386                 zf_timer_off();
 387         }
 388
 389         return NOTIFY_DONE;
 390 }
 391
 392
 393
 394
 395 static const struct file_operations zf_fops = {
 396         .owner          = THIS_MODULE,
 397         .llseek         = no_llseek,
 398         .write          = zf_write,
 399         .ioctl          = zf_ioctl,
 400         .open           = zf_open,
 401         .release        = zf_close,
 402 };
 403
 404 static struct miscdevice zf_miscdev = {
 405         .minor = WATCHDOG_MINOR,
 406         .name = "watchdog",
 407         .fops = &zf_fops,
 408 };
 409
 410
 411 /*
 412  * The device needs to learn about soft shutdowns in order to
 413  * turn the timebomb registers off.
 414  */
 415 static struct notifier_block zf_notifier = {
 416         .notifier_call = zf_notify_sys,
 417 };
 418
 419 static void __init zf_show_action(int act)
 420 {
 421         char *str[] = { "RESET", "SMI", "NMI", "SCI" };
 422
 423         printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
 424 }
 425
 426 static int __init zf_init(void)
 427 {
 428         int ret;
 429
 430         printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
 431
 432         ret = zf_get_ZFL_version();
 433         if ((!ret) || (ret == 0xffff)) {
 434                 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
 435                 return -ENODEV;
 436         }
 437
 438         if((action <= 3) && (action >= 0)){
 439                 zf_action = zf_action>>action;
 440         } else
 441                 action = 0;
 442
 443         zf_show_action(action);
 444
 445         if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
 446                 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
 447                                                         ZF_IOBASE);
 448                 ret = -EBUSY;
 449                 goto no_region;
 450         }
 451
 452         ret = register_reboot_notifier(&zf_notifier);
 453         if(ret){
 454                 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
 455                                                                         ret);
 456                 goto no_reboot;
 457         }
 458
 459         ret = misc_register(&zf_miscdev);
 460         if (ret){
 461                 printk(KERN_ERR "can't misc_register on minor=%d\n",
 462                                                         WATCHDOG_MINOR);
 463                 goto no_misc;
 464         }
 465
 466         zf_set_status(0);
 467         zf_set_control(0);
 468
 469         return 0;
 470
 471 no_misc:
 472         unregister_reboot_notifier(&zf_notifier);
 473 no_reboot:
 474         release_region(ZF_IOBASE, 3);
 475 no_region:
 476         return ret;
 477 }
 478
 479
 480 static void __exit zf_exit(void)
 481 {
 482         zf_timer_off();
 483
 484         misc_deregister(&zf_miscdev);
 485         unregister_reboot_notifier(&zf_notifier);
 486         release_region(ZF_IOBASE, 3);
 487 }
 488
 489 module_init(zf_init);
 490 module_exit(zf_exit);