drivers/char/watchdog/pcwd.c

   1 /*
   2  * PC Watchdog Driver
   3  * by Ken Hollis (khollis@bitgate.com)
   4  *
   5  * Permission granted from Simon Machell (73244.1270@compuserve.com)
   6  * Written for the Linux Kernel, and GPLed by Ken Hollis
   7  *
   8  * 960107       Added request_region routines, modulized the whole thing.
   9  * 960108       Fixed end-of-file pointer (Thanks to Dan Hollis), added
  10  *              WD_TIMEOUT define.
  11  * 960216       Added eof marker on the file, and changed verbose messages.
  12  * 960716       Made functional and cosmetic changes to the source for
  13  *              inclusion in Linux 2.0.x kernels, thanks to Alan Cox.
  14  * 960717       Removed read/seek routines, replaced with ioctl.  Also, added
  15  *              check_region command due to Alan's suggestion.
  16  * 960821       Made changes to compile in newer 2.0.x kernels.  Added
  17  *              "cold reboot sense" entry.
  18  * 960825       Made a few changes to code, deleted some defines and made
  19  *              typedefs to replace them.  Made heartbeat reset only available
  20  *              via ioctl, and removed the write routine.
  21  * 960828       Added new items for PC Watchdog Rev.C card.
  22  * 960829       Changed around all of the IOCTLs, added new features,
  23  *              added watchdog disable/re-enable routines.  Added firmware
  24  *              version reporting.  Added read routine for temperature.
  25  *              Removed some extra defines, added an autodetect Revision
  26  *              routine.
  27  * 961006       Revised some documentation, fixed some cosmetic bugs.  Made
  28  *              drivers to panic the system if it's overheating at bootup.
  29  * 961118       Changed some verbiage on some of the output, tidied up
  30  *              code bits, and added compatibility to 2.1.x.
  31  * 970912       Enabled board on open and disable on close.
  32  * 971107       Took account of recent VFS changes (broke read).
  33  * 971210       Disable board on initialisation in case board already ticking.
  34  * 971222       Changed open/close for temperature handling
  35  *              Michael Meskes <meskes@debian.org>.
  36  * 980112       Used minor numbers from include/linux/miscdevice.h
  37  * 990403       Clear reset status after reading control status register in
  38  *              pcwd_showprevstate(). [Marc Boucher <marc@mbsi.ca>]
  39  * 990605       Made changes to code to support Firmware 1.22a, added
  40  *              fairly useless proc entry.
  41  * 990610       removed said useless proc code for the merge <alan>
  42  * 000403       Removed last traces of proc code. <davej>
  43  * 011214       Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT <Matt_Domsch@dell.com>
  44  *              Added timeout module option to override default
  45  */
  46
  47 /*
  48  *      A bells and whistles driver is available from http://www.pcwd.de/
  49  *      More info available at http://www.berkprod.com/ or http://www.pcwatchdog.com/
  50  */
  51
  52 #include <linux/config.h>       /* For CONFIG_WATCHDOG_NOWAYOUT/... */
  53 #include <linux/module.h>       /* For module specific items */
  54 #include <linux/moduleparam.h>  /* For new moduleparam's */
  55 #include <linux/types.h>        /* For standard types (like size_t) */
  56 #include <linux/errno.h>        /* For the -ENODEV/... values */
  57 #include <linux/kernel.h>       /* For printk/panic/... */
  58 #include <linux/delay.h>        /* For mdelay function */
  59 #include <linux/timer.h>        /* For timer related operations */
  60 #include <linux/jiffies.h>      /* For jiffies stuff */
  61 #include <linux/miscdevice.h>   /* For MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) */
  62 #include <linux/watchdog.h>     /* For the watchdog specific items */
  63 #include <linux/notifier.h>     /* For notifier support */
  64 #include <linux/reboot.h>       /* For reboot_notifier stuff */
  65 #include <linux/init.h>         /* For __init/__exit/... */
  66 #include <linux/fs.h>           /* For file operations */
  67 #include <linux/ioport.h>       /* For io-port access */
  68 #include <linux/spinlock.h>     /* For spin_lock/spin_unlock/... */
  69 #include <linux/sched.h>        /* TASK_INTERRUPTIBLE, set_current_state() and friends */
  70 #include <linux/slab.h>         /* For kmalloc */
  71
  72 #include <asm/uaccess.h>        /* For copy_to_user/put_user/... */
  73 #include <asm/io.h>             /* For inb/outb/... */
  74
  75 /* Module and version information */
  76 #define WD_VER                  "1.16 (03/01/2006)"
  77 #define PFX                     "pcwd: "
  78
  79 /*
  80  * It should be noted that PCWD_REVISION_B was removed because A and B
  81  * are essentially the same types of card, with the exception that B
  82  * has temperature reporting.  Since I didn't receive a Rev.B card,
  83  * the Rev.B card is not supported.  (It's a good thing too, as they
  84  * are no longer in production.)
  85  */
  86 #define PCWD_REVISION_A         1
  87 #define PCWD_REVISION_C         2
  88
  89 /*
  90  * These are the defines that describe the control status bits for the
  91  * PCI-PC Watchdog card.
  92 */
  93 /* Port 1 : Control Status #1 for the PC Watchdog card, revision A. */
  94 #define WD_WDRST                0x01    /* Previously reset state */
  95 #define WD_T110                 0x02    /* Temperature overheat sense */
  96 #define WD_HRTBT                0x04    /* Heartbeat sense */
  97 #define WD_RLY2                 0x08    /* External relay triggered */
  98 #define WD_SRLY2                0x80    /* Software external relay triggered */
  99 /* Port 1 : Control Status #1 for the PC Watchdog card, revision C. */
 100 #define WD_REVC_WTRP            0x01    /* Watchdog Trip status */
 101 #define WD_REVC_HRBT            0x02    /* Watchdog Heartbeat */
 102 #define WD_REVC_TTRP            0x04    /* Temperature Trip status */
 103 /* Port 2 : Control Status #2 */
 104 #define WD_WDIS                 0x10    /* Watchdog Disabled */
 105 #define WD_ENTP                 0x20    /* Watchdog Enable Temperature Trip */
 106 #define WD_SSEL                 0x40    /* Watchdog Switch Select (1:SW1 <-> 0:SW2) */
 107 #define WD_WCMD                 0x80    /* Watchdog Command Mode */
 108
 109 /* max. time we give an ISA watchdog card to process a command */
 110 /* 500ms for each 4 bit response (according to spec.) */
 111 #define ISA_COMMAND_TIMEOUT     1000
 112
 113 /* Watchdog's internal commands */
 114 #define CMD_ISA_IDLE                    0x00
 115 #define CMD_ISA_VERSION_INTEGER         0x01
 116 #define CMD_ISA_VERSION_TENTH           0x02
 117 #define CMD_ISA_VERSION_HUNDRETH        0x03
 118 #define CMD_ISA_VERSION_MINOR           0x04
 119 #define CMD_ISA_SWITCH_SETTINGS         0x05
 120 #define CMD_ISA_DELAY_TIME_2SECS        0x0A
 121 #define CMD_ISA_DELAY_TIME_4SECS        0x0B
 122 #define CMD_ISA_DELAY_TIME_8SECS        0x0C
 123
 124 /*
 125  * We are using an kernel timer to do the pinging of the watchdog
 126  * every ~500ms. We try to set the internal heartbeat of the
 127  * watchdog to 2 ms.
 128  */
 129
 130 #define WDT_INTERVAL (HZ/2+1)
 131
 132 /* We can only use 1 card due to the /dev/watchdog restriction */
 133 static int cards_found;
 134
 135 /* internal variables */
 136 static atomic_t open_allowed = ATOMIC_INIT(1);
 137 static char expect_close;
 138 static int temp_panic;
 139 static struct {                         /* this is private data for each ISA-PC watchdog card */
 140         int revision;                   /* The card's revision */
 141         int supports_temp;              /* Wether or not the card has a temperature device */
 142         int command_mode;               /* Wether or not the card is in command mode */
 143         int boot_status;                /* The card's boot status */
 144         int io_addr;                    /* The cards I/O address */
 145         spinlock_t io_lock;             /* the lock for io operations */
 146         struct timer_list timer;        /* The timer that pings the watchdog */
 147         unsigned long next_heartbeat;   /* the next_heartbeat for the timer */
 148 } pcwd_private;
 149
 150 /* module parameters */
 151 #define WATCHDOG_HEARTBEAT 60           /* 60 sec default heartbeat */
 152 static int heartbeat = WATCHDOG_HEARTBEAT;
 153 module_param(heartbeat, int, 0);
 154 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<=heartbeat<=7200, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
 155
 156 static int nowayout = WATCHDOG_NOWAYOUT;
 157 module_param(nowayout, int, 0);
 158 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
 159
 160 /*
 161  *      Internal functions
 162  */
 163
 164 static int send_isa_command(int cmd)
 165 {
 166         int i;
 167         int control_status;
 168         int port0, last_port0;  /* Double read for stabilising */
 169
 170         /* The WCMD bit must be 1 and the command is only 4 bits in size */
 171         control_status = (cmd & 0x0F) | WD_WCMD;
 172         outb_p(control_status, pcwd_private.io_addr + 2);
 173         udelay(ISA_COMMAND_TIMEOUT);
 174
 175         port0 = inb_p(pcwd_private.io_addr);
 176         for (i = 0; i < 25; ++i) {
 177                 last_port0 = port0;
 178                 port0 = inb_p(pcwd_private.io_addr);
 179
 180                 if (port0 == last_port0)
 181                         break;  /* Data is stable */
 182
 183                 udelay (250);
 184         }
 185
 186         return port0;
 187 }
 188
 189 static int set_command_mode(void)
 190 {
 191         int i, found=0, count=0;
 192
 193         /* Set the card into command mode */
 194         spin_lock(&pcwd_private.io_lock);
 195         while ((!found) && (count < 3)) {
 196                 i = send_isa_command(CMD_ISA_IDLE);
 197
 198                 if (i == 0x00)
 199                         found = 1;
 200                 else if (i == 0xF3) {
 201                         /* Card does not like what we've done to it */
 202                         outb_p(0x00, pcwd_private.io_addr + 2);
 203                         udelay(1200);   /* Spec says wait 1ms */
 204                         outb_p(0x00, pcwd_private.io_addr + 2);
 205                         udelay(ISA_COMMAND_TIMEOUT);
 206                 }
 207                 count++;
 208         }
 209         spin_unlock(&pcwd_private.io_lock);
 210         pcwd_private.command_mode = found;
 211
 212         return(found);
 213 }
 214
 215 static void unset_command_mode(void)
 216 {
 217         /* Set the card into normal mode */
 218         spin_lock(&pcwd_private.io_lock);
 219         outb_p(0x00, pcwd_private.io_addr + 2);
 220         udelay(ISA_COMMAND_TIMEOUT);
 221         spin_unlock(&pcwd_private.io_lock);
 222
 223         pcwd_private.command_mode = 0;
 224 }
 225
 226 static inline void pcwd_check_temperature_support(void)
 227 {
 228         if (inb(pcwd_private.io_addr) != 0xF0)
 229                 pcwd_private.supports_temp = 1;
 230 }
 231
 232 static inline char *get_firmware(void)
 233 {
 234         int one, ten, hund, minor;
 235         char *ret;
 236
 237         ret = kmalloc(6, GFP_KERNEL);
 238         if(ret == NULL)
 239                 return NULL;
 240
 241         if (set_command_mode()) {
 242                 one = send_isa_command(CMD_ISA_VERSION_INTEGER);
 243                 ten = send_isa_command(CMD_ISA_VERSION_TENTH);
 244                 hund = send_isa_command(CMD_ISA_VERSION_HUNDRETH);
 245                 minor = send_isa_command(CMD_ISA_VERSION_MINOR);
 246                 sprintf(ret, "%c.%c%c%c", one, ten, hund, minor);
 247         }
 248         else
 249                 sprintf(ret, "ERROR");
 250
 251         unset_command_mode();
 252         return(ret);
 253 }
 254
 255 static inline int pcwd_get_option_switches(void)
 256 {
 257         int option_switches=0;
 258
 259         if (set_command_mode()) {
 260                 /* Get switch settings */
 261                 option_switches = send_isa_command(CMD_ISA_SWITCH_SETTINGS);
 262         }
 263
 264         unset_command_mode();
 265         return(option_switches);
 266 }
 267
 268 static void pcwd_show_card_info(void)
 269 {
 270         char *firmware;
 271         int option_switches;
 272
 273         /* Get some extra info from the hardware (in command/debug/diag mode) */
 274         if (pcwd_private.revision == PCWD_REVISION_A)
 275                 printk(KERN_INFO PFX "ISA-PC Watchdog (REV.A) detected at port 0x%04x\n", pcwd_private.io_addr);
 276         else if (pcwd_private.revision == PCWD_REVISION_C) {
 277                 firmware = get_firmware();
 278                 printk(KERN_INFO PFX "ISA-PC Watchdog (REV.C) detected at port 0x%04x (Firmware version: %s)\n",
 279                         pcwd_private.io_addr, firmware);
 280                 kfree(firmware);
 281                 option_switches = pcwd_get_option_switches();
 282                 printk(KERN_INFO PFX "Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
 283                         option_switches,
 284                         ((option_switches & 0x10) ? "ON" : "OFF"),
 285                         ((option_switches & 0x08) ? "ON" : "OFF"));
 286
 287                 /* Reprogram internal heartbeat to 2 seconds */
 288                 if (set_command_mode()) {
 289                         send_isa_command(CMD_ISA_DELAY_TIME_2SECS);
 290                         unset_command_mode();
 291                 }
 292         }
 293
 294         if (pcwd_private.supports_temp)
 295                 printk(KERN_INFO PFX "Temperature Option Detected\n");
 296
 297         if (pcwd_private.boot_status & WDIOF_CARDRESET)
 298                 printk(KERN_INFO PFX "Previous reboot was caused by the card\n");
 299
 300         if (pcwd_private.boot_status & WDIOF_OVERHEAT) {
 301                 printk(KERN_EMERG PFX "Card senses a CPU Overheat. Panicking!\n");
 302                 printk(KERN_EMERG PFX "CPU Overheat\n");
 303         }
 304
 305         if (pcwd_private.boot_status == 0)
 306                 printk(KERN_INFO PFX "No previous trip detected - Cold boot or reset\n");
 307 }
 308
 309 static void pcwd_timer_ping(unsigned long data)
 310 {
 311         int wdrst_stat;
 312
 313         /* If we got a heartbeat pulse within the WDT_INTERVAL
 314          * we agree to ping the WDT */
 315         if(time_before(jiffies, pcwd_private.next_heartbeat)) {
 316                 /* Ping the watchdog */
 317                 spin_lock(&pcwd_private.io_lock);
 318                 if (pcwd_private.revision == PCWD_REVISION_A) {
 319                         /*  Rev A cards are reset by setting the WD_WDRST bit in register 1 */
 320                         wdrst_stat = inb_p(pcwd_private.io_addr);
 321                         wdrst_stat &= 0x0F;
 322                         wdrst_stat |= WD_WDRST;
 323
 324                         outb_p(wdrst_stat, pcwd_private.io_addr + 1);
 325                 } else {
 326                         /* Re-trigger watchdog by writing to port 0 */
 327                         outb_p(0x00, pcwd_private.io_addr);
 328                 }
 329
 330                 /* Re-set the timer interval */
 331                 mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
 332
 333                 spin_unlock(&pcwd_private.io_lock);
 334         } else {
 335                 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
 336         }
 337 }
 338
 339 static int pcwd_start(void)
 340 {
 341         int stat_reg;
 342
 343         pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
 344
 345         /* Start the timer */
 346         mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
 347
 348         /* Enable the port */
 349         if (pcwd_private.revision == PCWD_REVISION_C) {
 350                 spin_lock(&pcwd_private.io_lock);
 351                 outb_p(0x00, pcwd_private.io_addr + 3);
 352                 udelay(ISA_COMMAND_TIMEOUT);
 353                 stat_reg = inb_p(pcwd_private.io_addr + 2);
 354                 spin_unlock(&pcwd_private.io_lock);
 355                 if (stat_reg & WD_WDIS) {
 356                         printk(KERN_INFO PFX "Could not start watchdog\n");
 357                         return -EIO;
 358                 }
 359         }
 360         return 0;
 361 }
 362
 363 static int pcwd_stop(void)
 364 {
 365         int stat_reg;
 366
 367         /* Stop the timer */
 368         del_timer(&pcwd_private.timer);
 369
 370         /*  Disable the board  */
 371         if (pcwd_private.revision == PCWD_REVISION_C) {
 372                 spin_lock(&pcwd_private.io_lock);
 373                 outb_p(0xA5, pcwd_private.io_addr + 3);
 374                 udelay(ISA_COMMAND_TIMEOUT);
 375                 outb_p(0xA5, pcwd_private.io_addr + 3);
 376                 udelay(ISA_COMMAND_TIMEOUT);
 377                 stat_reg = inb_p(pcwd_private.io_addr + 2);
 378                 spin_unlock(&pcwd_private.io_lock);
 379                 if ((stat_reg & WD_WDIS) == 0) {
 380                         printk(KERN_INFO PFX "Could not stop watchdog\n");
 381                         return -EIO;
 382                 }
 383         }
 384         return 0;
 385 }
 386
 387 static int pcwd_keepalive(void)
 388 {
 389         /* user land ping */
 390         pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
 391         return 0;
 392 }
 393
 394 static int pcwd_set_heartbeat(int t)
 395 {
 396         if ((t < 2) || (t > 7200)) /* arbitrary upper limit */
 397                 return -EINVAL;
 398
 399         heartbeat = t;
 400         return 0;
 401 }
 402
 403 static int pcwd_get_status(int *status)
 404 {
 405         int card_status;
 406
 407         *status=0;
 408         spin_lock(&pcwd_private.io_lock);
 409         if (pcwd_private.revision == PCWD_REVISION_A)
 410                 /* Rev A cards return status information from
 411                  * the base register, which is used for the
 412                  * temperature in other cards. */
 413                 card_status = inb(pcwd_private.io_addr);
 414         else {
 415                 /* Rev C cards return card status in the base
 416                  * address + 1 register. And use different bits
 417                  * to indicate a card initiated reset, and an
 418                  * over-temperature condition. And the reboot
 419                  * status can be reset. */
 420                 card_status = inb(pcwd_private.io_addr + 1);
 421         }
 422         spin_unlock(&pcwd_private.io_lock);
 423
 424         if (pcwd_private.revision == PCWD_REVISION_A) {
 425                 if (card_status & WD_WDRST)
 426                         *status |= WDIOF_CARDRESET;
 427
 428                 if (card_status & WD_T110) {
 429                         *status |= WDIOF_OVERHEAT;
 430                         if (temp_panic) {
 431                                 printk (KERN_INFO PFX "Temperature overheat trip!\n");
 432                                 kernel_power_off();
 433                         }
 434                 }
 435         } else {
 436                 if (card_status & WD_REVC_WTRP)
 437                         *status |= WDIOF_CARDRESET;
 438
 439                 if (card_status & WD_REVC_TTRP) {
 440                         *status |= WDIOF_OVERHEAT;
 441                         if (temp_panic) {
 442                                 printk (KERN_INFO PFX "Temperature overheat trip!\n");
 443                                 kernel_power_off();
 444                         }
 445                 }
 446         }
 447
 448         return 0;
 449 }
 450
 451 static int pcwd_clear_status(void)
 452 {
 453         if (pcwd_private.revision == PCWD_REVISION_C) {
 454                 spin_lock(&pcwd_private.io_lock);
 455                 outb_p(0x00, pcwd_private.io_addr + 1); /* clear reset status */
 456                 spin_unlock(&pcwd_private.io_lock);
 457         }
 458         return 0;
 459 }
 460
 461 static int pcwd_get_temperature(int *temperature)
 462 {
 463         /* check that port 0 gives temperature info and no command results */
 464         if (pcwd_private.command_mode)
 465                 return -1;
 466
 467         *temperature = 0;
 468         if (!pcwd_private.supports_temp)
 469                 return -ENODEV;
 470
 471         /*
 472          * Convert celsius to fahrenheit, since this was
 473          * the decided 'standard' for this return value.
 474          */
 475         spin_lock(&pcwd_private.io_lock);
 476         *temperature = ((inb(pcwd_private.io_addr)) * 9 / 5) + 32;
 477         spin_unlock(&pcwd_private.io_lock);
 478
 479         return 0;
 480 }
 481
 482 /*
 483  *      /dev/watchdog handling
 484  */
 485
 486 static int pcwd_ioctl(struct inode *inode, struct file *file,
 487                       unsigned int cmd, unsigned long arg)
 488 {
 489         int rv;
 490         int status;
 491         int temperature;
 492         int new_heartbeat;
 493         int __user *argp = (int __user *)arg;
 494         static struct watchdog_info ident = {
 495                 .options =              WDIOF_OVERHEAT |
 496                                         WDIOF_CARDRESET |
 497                                         WDIOF_KEEPALIVEPING |
 498                                         WDIOF_SETTIMEOUT |
 499                                         WDIOF_MAGICCLOSE,
 500                 .firmware_version =     1,
 501                 .identity =             "PCWD",
 502         };
 503
 504         switch(cmd) {
 505         default:
 506                 return -ENOIOCTLCMD;
 507
 508         case WDIOC_GETSUPPORT:
 509                 if(copy_to_user(argp, &ident, sizeof(ident)))
 510                         return -EFAULT;
 511                 return 0;
 512
 513         case WDIOC_GETSTATUS:
 514                 pcwd_get_status(&status);
 515                 return put_user(status, argp);
 516
 517         case WDIOC_GETBOOTSTATUS:
 518                 return put_user(pcwd_private.boot_status, argp);
 519
 520         case WDIOC_GETTEMP:
 521                 if (pcwd_get_temperature(&temperature))
 522                         return -EFAULT;
 523
 524                 return put_user(temperature, argp);
 525
 526         case WDIOC_SETOPTIONS:
 527                 if (pcwd_private.revision == PCWD_REVISION_C)
 528                 {
 529                         if(copy_from_user(&rv, argp, sizeof(int)))
 530                                 return -EFAULT;
 531
 532                         if (rv & WDIOS_DISABLECARD)
 533                         {
 534                                 return pcwd_stop();
 535                         }
 536
 537                         if (rv & WDIOS_ENABLECARD)
 538                         {
 539                                 return pcwd_start();
 540                         }
 541
 542                         if (rv & WDIOS_TEMPPANIC)
 543                         {
 544                                 temp_panic = 1;
 545                         }
 546                 }
 547                 return -EINVAL;
 548
 549         case WDIOC_KEEPALIVE:
 550                 pcwd_keepalive();
 551                 return 0;
 552
 553         case WDIOC_SETTIMEOUT:
 554                 if (get_user(new_heartbeat, argp))
 555                         return -EFAULT;
 556
 557                 if (pcwd_set_heartbeat(new_heartbeat))
 558                         return -EINVAL;
 559
 560                 pcwd_keepalive();
 561                 /* Fall */
 562
 563         case WDIOC_GETTIMEOUT:
 564                 return put_user(heartbeat, argp);
 565         }
 566
 567         return 0;
 568 }
 569
 570 static ssize_t pcwd_write(struct file *file, const char __user *buf, size_t len,
 571                           loff_t *ppos)
 572 {
 573         if (len) {
 574                 if (!nowayout) {
 575                         size_t i;
 576
 577                         /* In case it was set long ago */
 578                         expect_close = 0;
 579
 580                         for (i = 0; i != len; i++) {
 581                                 char c;
 582
 583                                 if (get_user(c, buf + i))
 584                                         return -EFAULT;
 585                                 if (c == 'V')
 586                                         expect_close = 42;
 587                         }
 588                 }
 589                 pcwd_keepalive();
 590         }
 591         return len;
 592 }
 593
 594 static int pcwd_open(struct inode *inode, struct file *file)
 595 {
 596         if (!atomic_dec_and_test(&open_allowed) ) {
 597                 atomic_inc( &open_allowed );
 598                 return -EBUSY;
 599         }
 600
 601         if (nowayout)
 602                 __module_get(THIS_MODULE);
 603
 604         /* Activate */
 605         pcwd_start();
 606         pcwd_keepalive();
 607         return nonseekable_open(inode, file);
 608 }
 609
 610 static int pcwd_close(struct inode *inode, struct file *file)
 611 {
 612         if (expect_close == 42) {
 613                 pcwd_stop();
 614         } else {
 615                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 616                 pcwd_keepalive();
 617         }
 618         expect_close = 0;
 619         atomic_inc( &open_allowed );
 620         return 0;
 621 }
 622
 623 /*
 624  *      /dev/temperature handling
 625  */
 626
 627 static ssize_t pcwd_temp_read(struct file *file, char __user *buf, size_t count,
 628                          loff_t *ppos)
 629 {
 630         int temperature;
 631
 632         if (pcwd_get_temperature(&temperature))
 633                 return -EFAULT;
 634
 635         if (copy_to_user(buf, &temperature, 1))
 636                 return -EFAULT;
 637
 638         return 1;
 639 }
 640
 641 static int pcwd_temp_open(struct inode *inode, struct file *file)
 642 {
 643         if (!pcwd_private.supports_temp)
 644                 return -ENODEV;
 645
 646         return nonseekable_open(inode, file);
 647 }
 648
 649 static int pcwd_temp_close(struct inode *inode, struct file *file)
 650 {
 651         return 0;
 652 }
 653
 654 /*
 655  *      Notify system
 656  */
 657
 658 static int pcwd_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
 659 {
 660         if (code==SYS_DOWN || code==SYS_HALT) {
 661                 /* Turn the WDT off */
 662                 pcwd_stop();
 663         }
 664
 665         return NOTIFY_DONE;
 666 }
 667
 668 /*
 669  *      Kernel Interfaces
 670  */
 671
 672 static struct file_operations pcwd_fops = {
 673         .owner          = THIS_MODULE,
 674         .llseek         = no_llseek,
 675         .write          = pcwd_write,
 676         .ioctl          = pcwd_ioctl,
 677         .open           = pcwd_open,
 678         .release        = pcwd_close,
 679 };
 680
 681 static struct miscdevice pcwd_miscdev = {
 682         .minor =        WATCHDOG_MINOR,
 683         .name =         "watchdog",
 684         .fops =         &pcwd_fops,
 685 };
 686
 687 static struct file_operations pcwd_temp_fops = {
 688         .owner          = THIS_MODULE,
 689         .llseek         = no_llseek,
 690         .read           = pcwd_temp_read,
 691         .open           = pcwd_temp_open,
 692         .release        = pcwd_temp_close,
 693 };
 694
 695 static struct miscdevice temp_miscdev = {
 696         .minor =        TEMP_MINOR,
 697         .name =         "temperature",
 698         .fops =         &pcwd_temp_fops,
 699 };
 700
 701 static struct notifier_block pcwd_notifier = {
 702         .notifier_call =        pcwd_notify_sys,
 703 };
 704
 705 /*
 706  *      Init & exit routines
 707  */
 708
 709 static inline int get_revision(void)
 710 {
 711         int r = PCWD_REVISION_C;
 712
 713         spin_lock(&pcwd_private.io_lock);
 714         /* REV A cards use only 2 io ports; test
 715          * presumes a floating bus reads as 0xff. */
 716         if ((inb(pcwd_private.io_addr + 2) == 0xFF) ||
 717             (inb(pcwd_private.io_addr + 3) == 0xFF))
 718                 r=PCWD_REVISION_A;
 719         spin_unlock(&pcwd_private.io_lock);
 720
 721         return r;
 722 }
 723
 724 static int __devinit pcwatchdog_init(int base_addr)
 725 {
 726         int ret;
 727
 728         cards_found++;
 729         if (cards_found == 1)
 730                 printk(KERN_INFO PFX "v%s Ken Hollis (kenji@bitgate.com)\n", WD_VER);
 731
 732         if (cards_found > 1) {
 733                 printk(KERN_ERR PFX "This driver only supports 1 device\n");
 734                 return -ENODEV;
 735         }
 736
 737         if (base_addr == 0x0000) {
 738                 printk(KERN_ERR PFX "No I/O-Address for card detected\n");
 739                 return -ENODEV;
 740         }
 741         pcwd_private.io_addr = base_addr;
 742
 743         /* Check card's revision */
 744         pcwd_private.revision = get_revision();
 745
 746         if (!request_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4, "PCWD")) {
 747                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 748                         pcwd_private.io_addr);
 749                 pcwd_private.io_addr = 0x0000;
 750                 return -EIO;
 751         }
 752
 753         /* Initial variables */
 754         pcwd_private.supports_temp = 0;
 755         temp_panic = 0;
 756         pcwd_private.boot_status = 0x0000;
 757
 758         /* get the boot_status */
 759         pcwd_get_status(&pcwd_private.boot_status);
 760
 761         /* clear the "card caused reboot" flag */
 762         pcwd_clear_status();
 763
 764         init_timer(&pcwd_private.timer);
 765         pcwd_private.timer.function = pcwd_timer_ping;
 766         pcwd_private.timer.data = 0;
 767
 768         /*  Disable the board  */
 769         pcwd_stop();
 770
 771         /*  Check whether or not the card supports the temperature device */
 772         pcwd_check_temperature_support();
 773
 774         /* Show info about the card itself */
 775         pcwd_show_card_info();
 776
 777         /* Check that the heartbeat value is within it's range ; if not reset to the default */
 778         if (pcwd_set_heartbeat(heartbeat)) {
 779                 pcwd_set_heartbeat(WATCHDOG_HEARTBEAT);
 780                 printk(KERN_INFO PFX "heartbeat value must be 2<=heartbeat<=7200, using %d\n",
 781                         WATCHDOG_HEARTBEAT);
 782         }
 783
 784         ret = register_reboot_notifier(&pcwd_notifier);
 785         if (ret) {
 786                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 787                         ret);
 788                 release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 789                 pcwd_private.io_addr = 0x0000;
 790                 return ret;
 791         }
 792
 793         if (pcwd_private.supports_temp) {
 794                 ret = misc_register(&temp_miscdev);
 795                 if (ret) {
 796                         printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 797                                 TEMP_MINOR, ret);
 798                         unregister_reboot_notifier(&pcwd_notifier);
 799                         release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 800                         pcwd_private.io_addr = 0x0000;
 801                         return ret;
 802                 }
 803         }
 804
 805         ret = misc_register(&pcwd_miscdev);
 806         if (ret) {
 807                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 808                         WATCHDOG_MINOR, ret);
 809                 if (pcwd_private.supports_temp)
 810                         misc_deregister(&temp_miscdev);
 811                 unregister_reboot_notifier(&pcwd_notifier);
 812                 release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 813                 pcwd_private.io_addr = 0x0000;
 814                 return ret;
 815         }
 816
 817         printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
 818                 heartbeat, nowayout);
 819
 820         return 0;
 821 }
 822
 823 static void __devexit pcwatchdog_exit(void)
 824 {
 825         /*  Disable the board  */
 826         if (!nowayout)
 827                 pcwd_stop();
 828
 829         /* Deregister */
 830         misc_deregister(&pcwd_miscdev);
 831         if (pcwd_private.supports_temp)
 832                 misc_deregister(&temp_miscdev);
 833         unregister_reboot_notifier(&pcwd_notifier);
 834         release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 835         pcwd_private.io_addr = 0x0000;
 836         cards_found--;
 837 }
 838
 839 /*
 840  *  The ISA cards have a heartbeat bit in one of the registers, which
 841  *  register is card dependent.  The heartbeat bit is monitored, and if
 842  *  found, is considered proof that a Berkshire card has been found.
 843  *  The initial rate is once per second at board start up, then twice
 844  *  per second for normal operation.
 845  */
 846 static int __init pcwd_checkcard(int base_addr)
 847 {
 848         int port0, last_port0;  /* Reg 0, in case it's REV A */
 849         int port1, last_port1;  /* Register 1 for REV C cards */
 850         int i;
 851         int retval;
 852
 853         if (!request_region (base_addr, 4, "PCWD")) {
 854                 printk (KERN_INFO PFX "Port 0x%04x unavailable\n", base_addr);
 855                 return 0;
 856         }
 857
 858         retval = 0;
 859
 860         port0 = inb_p(base_addr);       /* For REV A boards */
 861         port1 = inb_p(base_addr + 1);   /* For REV C boards */
 862         if (port0 != 0xff || port1 != 0xff) {
 863                 /* Not an 'ff' from a floating bus, so must be a card! */
 864                 for (i = 0; i < 4; ++i) {
 865
 866                         msleep(500);
 867
 868                         last_port0 = port0;
 869                         last_port1 = port1;
 870
 871                         port0 = inb_p(base_addr);
 872                         port1 = inb_p(base_addr + 1);
 873
 874                         /* Has either hearbeat bit changed?  */
 875                         if ((port0 ^ last_port0) & WD_HRTBT ||
 876                             (port1 ^ last_port1) & WD_REVC_HRBT) {
 877                                 retval = 1;
 878                                 break;
 879                         }
 880                 }
 881         }
 882         release_region (base_addr, 4);
 883
 884         return retval;
 885 }
 886
 887 /*
 888  * These are the auto-probe addresses available.
 889  *
 890  * Revision A only uses ports 0x270 and 0x370.  Revision C introduced 0x350.
 891  * Revision A has an address range of 2 addresses, while Revision C has 4.
 892  */
 893 static int pcwd_ioports[] = { 0x270, 0x350, 0x370, 0x000 };
 894
 895 static int __init pcwd_init_module(void)
 896 {
 897         int i, found = 0;
 898
 899         spin_lock_init(&pcwd_private.io_lock);
 900
 901         for (i = 0; pcwd_ioports[i] != 0; i++) {
 902                 if (pcwd_checkcard(pcwd_ioports[i])) {
 903                         if (!(pcwatchdog_init(pcwd_ioports[i])))
 904                                 found++;
 905                 }
 906         }
 907
 908         if (!found) {
 909                 printk (KERN_INFO PFX "No card detected, or port not available\n");
 910                 return -ENODEV;
 911         }
 912
 913         return 0;
 914 }
 915
 916 static void __exit pcwd_cleanup_module(void)
 917 {
 918         if (pcwd_private.io_addr)
 919                 pcwatchdog_exit();
 920         return;
 921 }
 922
 923 module_init(pcwd_init_module);
 924 module_exit(pcwd_cleanup_module);
 925
 926 MODULE_AUTHOR("Ken Hollis <kenji@bitgate.com>");
 927 MODULE_DESCRIPTION("Berkshire ISA-PC Watchdog driver");
 928 MODULE_LICENSE("GPL");
 929 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 930 MODULE_ALIAS_MISCDEV(TEMP_MINOR);