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 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  98 static int nowayout = 1;
  99 #else
 100 static int nowayout = 0;
 101 #endif
 102
 103 module_param(nowayout, int, 0);
 104 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
 105
 106 #define PFX "machzwd"
 107
 108 static struct watchdog_info zf_info = {
 109         .options                = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 110         .firmware_version       = 1,
 111         .identity               = "ZF-Logic watchdog",
 112 };
 113
 114
 115 /*
 116  * action refers to action taken when watchdog resets
 117  * 0 = GEN_RESET
 118  * 1 = GEN_SMI
 119  * 2 = GEN_NMI
 120  * 3 = GEN_SCI
 121  * defaults to GEN_RESET (0)
 122  */
 123 static int action = 0;
 124 module_param(action, int, 0);
 125 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*)  1 = SMI  2 = NMI  3 = SCI");
 126
 127 static int zf_action = GEN_RESET;
 128 static unsigned long zf_is_open;
 129 static char zf_expect_close;
 130 static spinlock_t zf_lock;
 131 static spinlock_t zf_port_lock;
 132 static struct timer_list zf_timer;
 133 static unsigned long next_heartbeat = 0;
 134
 135
 136 /* timeout for user land heart beat (10 seconds) */
 137 #define ZF_USER_TIMEO (HZ*10)
 138
 139 /* timeout for hardware watchdog (~500ms) */
 140 #define ZF_HW_TIMEO (HZ/2)
 141
 142 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
 143 #define ZF_CTIMEOUT 0xffff
 144
 145 #ifndef ZF_DEBUG
 146 #       define dprintk(format, args...)
 147 #else
 148 #       define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args)
 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         zf_timer.expires = jiffies + ZF_HW_TIMEO;
 230
 231         add_timer(&zf_timer);
 232
 233         /* start watchdog timer */
 234         ctrl_reg = zf_get_control();
 235         ctrl_reg |= (ENABLE_WD1|zf_action);
 236         zf_set_control(ctrl_reg);
 237         spin_unlock_irqrestore(&zf_port_lock, flags);
 238
 239         printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
 240 }
 241
 242
 243 static void zf_ping(unsigned long data)
 244 {
 245         unsigned int ctrl_reg = 0;
 246         unsigned long flags;
 247
 248         zf_writeb(COUNTER_2, 0xff);
 249
 250         if(time_before(jiffies, next_heartbeat)){
 251
 252                 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
 253
 254                 /*
 255                  * reset event is activated by transition from 0 to 1 on
 256                  * RESET_WD1 bit and we assume that it is already zero...
 257                  */
 258
 259                 spin_lock_irqsave(&zf_port_lock, flags);
 260                 ctrl_reg = zf_get_control();
 261                 ctrl_reg |= RESET_WD1;
 262                 zf_set_control(ctrl_reg);
 263
 264                 /* ...and nothing changes until here */
 265                 ctrl_reg &= ~(RESET_WD1);
 266                 zf_set_control(ctrl_reg);
 267                 spin_unlock_irqrestore(&zf_port_lock, flags);
 268
 269                 zf_timer.expires = jiffies + ZF_HW_TIMEO;
 270                 add_timer(&zf_timer);
 271         }else{
 272                 printk(KERN_CRIT PFX ": I will reset your machine\n");
 273         }
 274 }
 275
 276 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
 277                                                                 loff_t *ppos)
 278 {
 279         /* See if we got the magic character */
 280         if(count){
 281
 282                 /*
 283                  * no need to check for close confirmation
 284                  * no way to disable watchdog ;)
 285                  */
 286                 if (!nowayout) {
 287                         size_t ofs;
 288
 289                         /*
 290                          * note: just in case someone wrote the magic character
 291                          * five months ago...
 292                          */
 293                         zf_expect_close = 0;
 294
 295                         /* now scan */
 296                         for (ofs = 0; ofs != count; ofs++){
 297                                 char c;
 298                                 if (get_user(c, buf + ofs))
 299                                         return -EFAULT;
 300                                 if (c == 'V'){
 301                                         zf_expect_close = 42;
 302                                         dprintk("zf_expect_close = 42\n");
 303                                 }
 304                         }
 305                 }
 306
 307                 /*
 308                  * Well, anyhow someone wrote to us,
 309                  * we should return that favour
 310                  */
 311                 next_heartbeat = jiffies + ZF_USER_TIMEO;
 312                 dprintk("user ping at %ld\n", jiffies);
 313
 314         }
 315
 316         return count;
 317 }
 318
 319 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 320         unsigned long arg)
 321 {
 322         void __user *argp = (void __user *)arg;
 323         int __user *p = argp;
 324         switch(cmd){
 325                 case WDIOC_GETSUPPORT:
 326                         if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
 327                                 return -EFAULT;
 328                         break;
 329
 330                 case WDIOC_GETSTATUS:
 331                         return put_user(0, p);
 332
 333                 case WDIOC_KEEPALIVE:
 334                         zf_ping(0);
 335                         break;
 336
 337                 default:
 338                         return -ENOIOCTLCMD;
 339         }
 340
 341         return 0;
 342 }
 343
 344 static int zf_open(struct inode *inode, struct file *file)
 345 {
 346         spin_lock(&zf_lock);
 347         if(test_and_set_bit(0, &zf_is_open)) {
 348                 spin_unlock(&zf_lock);
 349                 return -EBUSY;
 350         }
 351
 352         if (nowayout)
 353                 __module_get(THIS_MODULE);
 354
 355         spin_unlock(&zf_lock);
 356
 357         zf_timer_on();
 358
 359         return nonseekable_open(inode, file);
 360 }
 361
 362 static int zf_close(struct inode *inode, struct file *file)
 363 {
 364         if(zf_expect_close == 42){
 365                 zf_timer_off();
 366         } else {
 367                 del_timer(&zf_timer);
 368                 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
 369         }
 370
 371         spin_lock(&zf_lock);
 372         clear_bit(0, &zf_is_open);
 373         spin_unlock(&zf_lock);
 374
 375         zf_expect_close = 0;
 376
 377         return 0;
 378 }
 379
 380 /*
 381  * Notifier for system down
 382  */
 383
 384 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
 385                                                                 void *unused)
 386 {
 387         if(code == SYS_DOWN || code == SYS_HALT){
 388                 zf_timer_off();
 389         }
 390
 391         return NOTIFY_DONE;
 392 }
 393
 394
 395
 396
 397 static struct file_operations zf_fops = {
 398         .owner          = THIS_MODULE,
 399         .llseek         = no_llseek,
 400         .write          = zf_write,
 401         .ioctl          = zf_ioctl,
 402         .open           = zf_open,
 403         .release        = zf_close,
 404 };
 405
 406 static struct miscdevice zf_miscdev = {
 407         .minor = WATCHDOG_MINOR,
 408         .name = "watchdog",
 409         .fops = &zf_fops,
 410 };
 411
 412
 413 /*
 414  * The device needs to learn about soft shutdowns in order to
 415  * turn the timebomb registers off.
 416  */
 417 static struct notifier_block zf_notifier = {
 418         .notifier_call = zf_notify_sys,
 419 };
 420
 421 static void __init zf_show_action(int act)
 422 {
 423         char *str[] = { "RESET", "SMI", "NMI", "SCI" };
 424
 425         printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
 426 }
 427
 428 static int __init zf_init(void)
 429 {
 430         int ret;
 431
 432         printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
 433
 434         ret = zf_get_ZFL_version();
 435         printk("%#x\n", ret);
 436         if((!ret) || (ret != 0xffff)){
 437                 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
 438                 return -ENODEV;
 439         }
 440
 441         if((action <= 3) && (action >= 0)){
 442                 zf_action = zf_action>>action;
 443         } else
 444                 action = 0;
 445
 446         zf_show_action(action);
 447
 448         spin_lock_init(&zf_lock);
 449         spin_lock_init(&zf_port_lock);
 450
 451         ret = misc_register(&zf_miscdev);
 452         if (ret){
 453                 printk(KERN_ERR "can't misc_register on minor=%d\n",
 454                                                         WATCHDOG_MINOR);
 455                 goto out;
 456         }
 457
 458         if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
 459                 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
 460                                                         ZF_IOBASE);
 461                 ret = -EBUSY;
 462                 goto no_region;
 463         }
 464
 465         ret = register_reboot_notifier(&zf_notifier);
 466         if(ret){
 467                 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
 468                                                                         ret);
 469                 goto no_reboot;
 470         }
 471
 472         zf_set_status(0);
 473         zf_set_control(0);
 474
 475         /* this is the timer that will do the hard work */
 476         init_timer(&zf_timer);
 477         zf_timer.function = zf_ping;
 478         zf_timer.data = 0;
 479
 480         return 0;
 481
 482 no_reboot:
 483         release_region(ZF_IOBASE, 3);
 484 no_region:
 485         misc_deregister(&zf_miscdev);
 486 out:
 487         return ret;
 488 }
 489
 490
 491 static void __exit zf_exit(void)
 492 {
 493         zf_timer_off();
 494
 495         misc_deregister(&zf_miscdev);
 496         unregister_reboot_notifier(&zf_notifier);
 497         release_region(ZF_IOBASE, 3);
 498 }
 499
 500 module_init(zf_init);
 501 module_exit(zf_exit);