git.oblomov.eu Git - linux-2.6/blob - 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 WATCHDOG_VERSION "1.16"
  77 #define WATCHDOG_DATE "03 Jan 2006"
  78 #define WATCHDOG_DRIVER_NAME "ISA-PC Watchdog"
  79 #define WATCHDOG_NAME "pcwd"
  80 #define PFX WATCHDOG_NAME ": "
  81 #define DRIVER_VERSION WATCHDOG_DRIVER_NAME " driver, v" WATCHDOG_VERSION " (" WATCHDOG_DATE ")\n"
  82 #define WD_VER WATCHDOG_VERSION " (" WATCHDOG_DATE ")"
  83
  84 /*
  85  * It should be noted that PCWD_REVISION_B was removed because A and B
  86  * are essentially the same types of card, with the exception that B
  87  * has temperature reporting.  Since I didn't receive a Rev.B card,
  88  * the Rev.B card is not supported.  (It's a good thing too, as they
  89  * are no longer in production.)
  90  */
  91 #define PCWD_REVISION_A         1
  92 #define PCWD_REVISION_C         2
  93
  94 /*
  95  * These are the defines that describe the control status bits for the
  96  * PCI-PC Watchdog card.
  97 */
  98 /* Port 1 : Control Status #1 for the PC Watchdog card, revision A. */
  99 #define WD_WDRST                0x01    /* Previously reset state */
 100 #define WD_T110                 0x02    /* Temperature overheat sense */
 101 #define WD_HRTBT                0x04    /* Heartbeat sense */
 102 #define WD_RLY2                 0x08    /* External relay triggered */
 103 #define WD_SRLY2                0x80    /* Software external relay triggered */
 104 /* Port 1 : Control Status #1 for the PC Watchdog card, revision C. */
 105 #define WD_REVC_WTRP            0x01    /* Watchdog Trip status */
 106 #define WD_REVC_HRBT            0x02    /* Watchdog Heartbeat */
 107 #define WD_REVC_TTRP            0x04    /* Temperature Trip status */
 108 /* Port 2 : Control Status #2 */
 109 #define WD_WDIS                 0x10    /* Watchdog Disabled */
 110 #define WD_ENTP                 0x20    /* Watchdog Enable Temperature Trip */
 111 #define WD_SSEL                 0x40    /* Watchdog Switch Select (1:SW1 <-> 0:SW2) */
 112 #define WD_WCMD                 0x80    /* Watchdog Command Mode */
 113
 114 /* max. time we give an ISA watchdog card to process a command */
 115 /* 500ms for each 4 bit response (according to spec.) */
 116 #define ISA_COMMAND_TIMEOUT     1000
 117
 118 /* Watchdog's internal commands */
 119 #define CMD_ISA_IDLE                    0x00
 120 #define CMD_ISA_VERSION_INTEGER         0x01
 121 #define CMD_ISA_VERSION_TENTH           0x02
 122 #define CMD_ISA_VERSION_HUNDRETH        0x03
 123 #define CMD_ISA_VERSION_MINOR           0x04
 124 #define CMD_ISA_SWITCH_SETTINGS         0x05
 125 #define CMD_ISA_DELAY_TIME_2SECS        0x0A
 126 #define CMD_ISA_DELAY_TIME_4SECS        0x0B
 127 #define CMD_ISA_DELAY_TIME_8SECS        0x0C
 128
 129 /*
 130  * We are using an kernel timer to do the pinging of the watchdog
 131  * every ~500ms. We try to set the internal heartbeat of the
 132  * watchdog to 2 ms.
 133  */
 134
 135 #define WDT_INTERVAL (HZ/2+1)
 136
 137 /* We can only use 1 card due to the /dev/watchdog restriction */
 138 static int cards_found;
 139
 140 /* internal variables */
 141 static atomic_t open_allowed = ATOMIC_INIT(1);
 142 static char expect_close;
 143 static int temp_panic;
 144 static struct {                         /* this is private data for each ISA-PC watchdog card */
 145         int revision;                   /* The card's revision */
 146         int supports_temp;              /* Wether or not the card has a temperature device */
 147         int command_mode;               /* Wether or not the card is in command mode */
 148         int boot_status;                /* The card's boot status */
 149         int io_addr;                    /* The cards I/O address */
 150         spinlock_t io_lock;             /* the lock for io operations */
 151         struct timer_list timer;        /* The timer that pings the watchdog */
 152         unsigned long next_heartbeat;   /* the next_heartbeat for the timer */
 153 } pcwd_private;
 154
 155 /* module parameters */
 156 #define WATCHDOG_HEARTBEAT 60           /* 60 sec default heartbeat */
 157 static int heartbeat = WATCHDOG_HEARTBEAT;
 158 module_param(heartbeat, int, 0);
 159 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<=heartbeat<=7200, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
 160
 161 static int nowayout = WATCHDOG_NOWAYOUT;
 162 module_param(nowayout, int, 0);
 163 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
 164
 165 /*
 166  *      Internal functions
 167  */
 168
 169 static int send_isa_command(int cmd)
 170 {
 171         int i;
 172         int control_status;
 173         int port0, last_port0;  /* Double read for stabilising */
 174
 175         /* The WCMD bit must be 1 and the command is only 4 bits in size */
 176         control_status = (cmd & 0x0F) | WD_WCMD;
 177         outb_p(control_status, pcwd_private.io_addr + 2);
 178         udelay(ISA_COMMAND_TIMEOUT);
 179
 180         port0 = inb_p(pcwd_private.io_addr);
 181         for (i = 0; i < 25; ++i) {
 182                 last_port0 = port0;
 183                 port0 = inb_p(pcwd_private.io_addr);
 184
 185                 if (port0 == last_port0)
 186                         break;  /* Data is stable */
 187
 188                 udelay (250);
 189         }
 190
 191         return port0;
 192 }
 193
 194 static int set_command_mode(void)
 195 {
 196         int i, found=0, count=0;
 197
 198         /* Set the card into command mode */
 199         spin_lock(&pcwd_private.io_lock);
 200         while ((!found) && (count < 3)) {
 201                 i = send_isa_command(CMD_ISA_IDLE);
 202
 203                 if (i == 0x00)
 204                         found = 1;
 205                 else if (i == 0xF3) {
 206                         /* Card does not like what we've done to it */
 207                         outb_p(0x00, pcwd_private.io_addr + 2);
 208                         udelay(1200);   /* Spec says wait 1ms */
 209                         outb_p(0x00, pcwd_private.io_addr + 2);
 210                         udelay(ISA_COMMAND_TIMEOUT);
 211                 }
 212                 count++;
 213         }
 214         spin_unlock(&pcwd_private.io_lock);
 215         pcwd_private.command_mode = found;
 216
 217         return(found);
 218 }
 219
 220 static void unset_command_mode(void)
 221 {
 222         /* Set the card into normal mode */
 223         spin_lock(&pcwd_private.io_lock);
 224         outb_p(0x00, pcwd_private.io_addr + 2);
 225         udelay(ISA_COMMAND_TIMEOUT);
 226         spin_unlock(&pcwd_private.io_lock);
 227
 228         pcwd_private.command_mode = 0;
 229 }
 230
 231 static inline void pcwd_check_temperature_support(void)
 232 {
 233         if (inb(pcwd_private.io_addr) != 0xF0)
 234                 pcwd_private.supports_temp = 1;
 235 }
 236
 237 static inline char *get_firmware(void)
 238 {
 239         int one, ten, hund, minor;
 240         char *ret;
 241
 242         ret = kmalloc(6, GFP_KERNEL);
 243         if(ret == NULL)
 244                 return NULL;
 245
 246         if (set_command_mode()) {
 247                 one = send_isa_command(CMD_ISA_VERSION_INTEGER);
 248                 ten = send_isa_command(CMD_ISA_VERSION_TENTH);
 249                 hund = send_isa_command(CMD_ISA_VERSION_HUNDRETH);
 250                 minor = send_isa_command(CMD_ISA_VERSION_MINOR);
 251                 sprintf(ret, "%c.%c%c%c", one, ten, hund, minor);
 252         }
 253         else
 254                 sprintf(ret, "ERROR");
 255
 256         unset_command_mode();
 257         return(ret);
 258 }
 259
 260 static inline int pcwd_get_option_switches(void)
 261 {
 262         int option_switches=0;
 263
 264         if (set_command_mode()) {
 265                 /* Get switch settings */
 266                 option_switches = send_isa_command(CMD_ISA_SWITCH_SETTINGS);
 267         }
 268
 269         unset_command_mode();
 270         return(option_switches);
 271 }
 272
 273 static void pcwd_show_card_info(void)
 274 {
 275         char *firmware;
 276         int option_switches;
 277
 278         /* Get some extra info from the hardware (in command/debug/diag mode) */
 279         if (pcwd_private.revision == PCWD_REVISION_A)
 280                 printk(KERN_INFO PFX "ISA-PC Watchdog (REV.A) detected at port 0x%04x\n", pcwd_private.io_addr);
 281         else if (pcwd_private.revision == PCWD_REVISION_C) {
 282                 firmware = get_firmware();
 283                 printk(KERN_INFO PFX "ISA-PC Watchdog (REV.C) detected at port 0x%04x (Firmware version: %s)\n",
 284                         pcwd_private.io_addr, firmware);
 285                 kfree(firmware);
 286                 option_switches = pcwd_get_option_switches();
 287                 printk(KERN_INFO PFX "Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
 288                         option_switches,
 289                         ((option_switches & 0x10) ? "ON" : "OFF"),
 290                         ((option_switches & 0x08) ? "ON" : "OFF"));
 291
 292                 /* Reprogram internal heartbeat to 2 seconds */
 293                 if (set_command_mode()) {
 294                         send_isa_command(CMD_ISA_DELAY_TIME_2SECS);
 295                         unset_command_mode();
 296                 }
 297         }
 298
 299         if (pcwd_private.supports_temp)
 300                 printk(KERN_INFO PFX "Temperature Option Detected\n");
 301
 302         if (pcwd_private.boot_status & WDIOF_CARDRESET)
 303                 printk(KERN_INFO PFX "Previous reboot was caused by the card\n");
 304
 305         if (pcwd_private.boot_status & WDIOF_OVERHEAT) {
 306                 printk(KERN_EMERG PFX "Card senses a CPU Overheat. Panicking!\n");
 307                 printk(KERN_EMERG PFX "CPU Overheat\n");
 308         }
 309
 310         if (pcwd_private.boot_status == 0)
 311                 printk(KERN_INFO PFX "No previous trip detected - Cold boot or reset\n");
 312 }
 313
 314 static void pcwd_timer_ping(unsigned long data)
 315 {
 316         int wdrst_stat;
 317
 318         /* If we got a heartbeat pulse within the WDT_INTERVAL
 319          * we agree to ping the WDT */
 320         if(time_before(jiffies, pcwd_private.next_heartbeat)) {
 321                 /* Ping the watchdog */
 322                 spin_lock(&pcwd_private.io_lock);
 323                 if (pcwd_private.revision == PCWD_REVISION_A) {
 324                         /*  Rev A cards are reset by setting the WD_WDRST bit in register 1 */
 325                         wdrst_stat = inb_p(pcwd_private.io_addr);
 326                         wdrst_stat &= 0x0F;
 327                         wdrst_stat |= WD_WDRST;
 328
 329                         outb_p(wdrst_stat, pcwd_private.io_addr + 1);
 330                 } else {
 331                         /* Re-trigger watchdog by writing to port 0 */
 332                         outb_p(0x00, pcwd_private.io_addr);
 333                 }
 334
 335                 /* Re-set the timer interval */
 336                 mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
 337
 338                 spin_unlock(&pcwd_private.io_lock);
 339         } else {
 340                 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
 341         }
 342 }
 343
 344 static int pcwd_start(void)
 345 {
 346         int stat_reg;
 347
 348         pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
 349
 350         /* Start the timer */
 351         mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
 352
 353         /* Enable the port */
 354         if (pcwd_private.revision == PCWD_REVISION_C) {
 355                 spin_lock(&pcwd_private.io_lock);
 356                 outb_p(0x00, pcwd_private.io_addr + 3);
 357                 udelay(ISA_COMMAND_TIMEOUT);
 358                 stat_reg = inb_p(pcwd_private.io_addr + 2);
 359                 spin_unlock(&pcwd_private.io_lock);
 360                 if (stat_reg & WD_WDIS) {
 361                         printk(KERN_INFO PFX "Could not start watchdog\n");
 362                         return -EIO;
 363                 }
 364         }
 365         return 0;
 366 }
 367
 368 static int pcwd_stop(void)
 369 {
 370         int stat_reg;
 371
 372         /* Stop the timer */
 373         del_timer(&pcwd_private.timer);
 374
 375         /*  Disable the board  */
 376         if (pcwd_private.revision == PCWD_REVISION_C) {
 377                 spin_lock(&pcwd_private.io_lock);
 378                 outb_p(0xA5, pcwd_private.io_addr + 3);
 379                 udelay(ISA_COMMAND_TIMEOUT);
 380                 outb_p(0xA5, pcwd_private.io_addr + 3);
 381                 udelay(ISA_COMMAND_TIMEOUT);
 382                 stat_reg = inb_p(pcwd_private.io_addr + 2);
 383                 spin_unlock(&pcwd_private.io_lock);
 384                 if ((stat_reg & WD_WDIS) == 0) {
 385                         printk(KERN_INFO PFX "Could not stop watchdog\n");
 386                         return -EIO;
 387                 }
 388         }
 389         return 0;
 390 }
 391
 392 static int pcwd_keepalive(void)
 393 {
 394         /* user land ping */
 395         pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
 396         return 0;
 397 }
 398
 399 static int pcwd_set_heartbeat(int t)
 400 {
 401         if ((t < 2) || (t > 7200)) /* arbitrary upper limit */
 402                 return -EINVAL;
 403
 404         heartbeat = t;
 405         return 0;
 406 }
 407
 408 static int pcwd_get_status(int *status)
 409 {
 410         int card_status;
 411
 412         *status=0;
 413         spin_lock(&pcwd_private.io_lock);
 414         if (pcwd_private.revision == PCWD_REVISION_A)
 415                 /* Rev A cards return status information from
 416                  * the base register, which is used for the
 417                  * temperature in other cards. */
 418                 card_status = inb(pcwd_private.io_addr);
 419         else {
 420                 /* Rev C cards return card status in the base
 421                  * address + 1 register. And use different bits
 422                  * to indicate a card initiated reset, and an
 423                  * over-temperature condition. And the reboot
 424                  * status can be reset. */
 425                 card_status = inb(pcwd_private.io_addr + 1);
 426         }
 427         spin_unlock(&pcwd_private.io_lock);
 428
 429         if (pcwd_private.revision == PCWD_REVISION_A) {
 430                 if (card_status & WD_WDRST)
 431                         *status |= WDIOF_CARDRESET;
 432
 433                 if (card_status & WD_T110) {
 434                         *status |= WDIOF_OVERHEAT;
 435                         if (temp_panic) {
 436                                 printk (KERN_INFO PFX "Temperature overheat trip!\n");
 437                                 kernel_power_off();
 438                         }
 439                 }
 440         } else {
 441                 if (card_status & WD_REVC_WTRP)
 442                         *status |= WDIOF_CARDRESET;
 443
 444                 if (card_status & WD_REVC_TTRP) {
 445                         *status |= WDIOF_OVERHEAT;
 446                         if (temp_panic) {
 447                                 printk (KERN_INFO PFX "Temperature overheat trip!\n");
 448                                 kernel_power_off();
 449                         }
 450                 }
 451         }
 452
 453         return 0;
 454 }
 455
 456 static int pcwd_clear_status(void)
 457 {
 458         if (pcwd_private.revision == PCWD_REVISION_C) {
 459                 spin_lock(&pcwd_private.io_lock);
 460                 outb_p(0x00, pcwd_private.io_addr + 1); /* clear reset status */
 461                 spin_unlock(&pcwd_private.io_lock);
 462         }
 463         return 0;
 464 }
 465
 466 static int pcwd_get_temperature(int *temperature)
 467 {
 468         /* check that port 0 gives temperature info and no command results */
 469         if (pcwd_private.command_mode)
 470                 return -1;
 471
 472         *temperature = 0;
 473         if (!pcwd_private.supports_temp)
 474                 return -ENODEV;
 475
 476         /*
 477          * Convert celsius to fahrenheit, since this was
 478          * the decided 'standard' for this return value.
 479          */
 480         spin_lock(&pcwd_private.io_lock);
 481         *temperature = ((inb(pcwd_private.io_addr)) * 9 / 5) + 32;
 482         spin_unlock(&pcwd_private.io_lock);
 483
 484         return 0;
 485 }
 486
 487 /*
 488  *      /dev/watchdog handling
 489  */
 490
 491 static int pcwd_ioctl(struct inode *inode, struct file *file,
 492                       unsigned int cmd, unsigned long arg)
 493 {
 494         int rv;
 495         int status;
 496         int temperature;
 497         int new_heartbeat;
 498         int __user *argp = (int __user *)arg;
 499         static struct watchdog_info ident = {
 500                 .options =              WDIOF_OVERHEAT |
 501                                         WDIOF_CARDRESET |
 502                                         WDIOF_KEEPALIVEPING |
 503                                         WDIOF_SETTIMEOUT |
 504                                         WDIOF_MAGICCLOSE,
 505                 .firmware_version =     1,
 506                 .identity =             "PCWD",
 507         };
 508
 509         switch(cmd) {
 510         default:
 511                 return -ENOIOCTLCMD;
 512
 513         case WDIOC_GETSUPPORT:
 514                 if(copy_to_user(argp, &ident, sizeof(ident)))
 515                         return -EFAULT;
 516                 return 0;
 517
 518         case WDIOC_GETSTATUS:
 519                 pcwd_get_status(&status);
 520                 return put_user(status, argp);
 521
 522         case WDIOC_GETBOOTSTATUS:
 523                 return put_user(pcwd_private.boot_status, argp);
 524
 525         case WDIOC_GETTEMP:
 526                 if (pcwd_get_temperature(&temperature))
 527                         return -EFAULT;
 528
 529                 return put_user(temperature, argp);
 530
 531         case WDIOC_SETOPTIONS:
 532                 if (pcwd_private.revision == PCWD_REVISION_C)
 533                 {
 534                         if(copy_from_user(&rv, argp, sizeof(int)))
 535                                 return -EFAULT;
 536
 537                         if (rv & WDIOS_DISABLECARD)
 538                         {
 539                                 return pcwd_stop();
 540                         }
 541
 542                         if (rv & WDIOS_ENABLECARD)
 543                         {
 544                                 return pcwd_start();
 545                         }
 546
 547                         if (rv & WDIOS_TEMPPANIC)
 548                         {
 549                                 temp_panic = 1;
 550                         }
 551                 }
 552                 return -EINVAL;
 553
 554         case WDIOC_KEEPALIVE:
 555                 pcwd_keepalive();
 556                 return 0;
 557
 558         case WDIOC_SETTIMEOUT:
 559                 if (get_user(new_heartbeat, argp))
 560                         return -EFAULT;
 561
 562                 if (pcwd_set_heartbeat(new_heartbeat))
 563                         return -EINVAL;
 564
 565                 pcwd_keepalive();
 566                 /* Fall */
 567
 568         case WDIOC_GETTIMEOUT:
 569                 return put_user(heartbeat, argp);
 570         }
 571
 572         return 0;
 573 }
 574
 575 static ssize_t pcwd_write(struct file *file, const char __user *buf, size_t len,
 576                           loff_t *ppos)
 577 {
 578         if (len) {
 579                 if (!nowayout) {
 580                         size_t i;
 581
 582                         /* In case it was set long ago */
 583                         expect_close = 0;
 584
 585                         for (i = 0; i != len; i++) {
 586                                 char c;
 587
 588                                 if (get_user(c, buf + i))
 589                                         return -EFAULT;
 590                                 if (c == 'V')
 591                                         expect_close = 42;
 592                         }
 593                 }
 594                 pcwd_keepalive();
 595         }
 596         return len;
 597 }
 598
 599 static int pcwd_open(struct inode *inode, struct file *file)
 600 {
 601         if (!atomic_dec_and_test(&open_allowed) ) {
 602                 atomic_inc( &open_allowed );
 603                 return -EBUSY;
 604         }
 605
 606         if (nowayout)
 607                 __module_get(THIS_MODULE);
 608
 609         /* Activate */
 610         pcwd_start();
 611         pcwd_keepalive();
 612         return nonseekable_open(inode, file);
 613 }
 614
 615 static int pcwd_close(struct inode *inode, struct file *file)
 616 {
 617         if (expect_close == 42) {
 618                 pcwd_stop();
 619         } else {
 620                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 621                 pcwd_keepalive();
 622         }
 623         expect_close = 0;
 624         atomic_inc( &open_allowed );
 625         return 0;
 626 }
 627
 628 /*
 629  *      /dev/temperature handling
 630  */
 631
 632 static ssize_t pcwd_temp_read(struct file *file, char __user *buf, size_t count,
 633                          loff_t *ppos)
 634 {
 635         int temperature;
 636
 637         if (pcwd_get_temperature(&temperature))
 638                 return -EFAULT;
 639
 640         if (copy_to_user(buf, &temperature, 1))
 641                 return -EFAULT;
 642
 643         return 1;
 644 }
 645
 646 static int pcwd_temp_open(struct inode *inode, struct file *file)
 647 {
 648         if (!pcwd_private.supports_temp)
 649                 return -ENODEV;
 650
 651         return nonseekable_open(inode, file);
 652 }
 653
 654 static int pcwd_temp_close(struct inode *inode, struct file *file)
 655 {
 656         return 0;
 657 }
 658
 659 /*
 660  *      Notify system
 661  */
 662
 663 static int pcwd_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
 664 {
 665         if (code==SYS_DOWN || code==SYS_HALT) {
 666                 /* Turn the WDT off */
 667                 pcwd_stop();
 668         }
 669
 670         return NOTIFY_DONE;
 671 }
 672
 673 /*
 674  *      Kernel Interfaces
 675  */
 676
 677 static struct file_operations pcwd_fops = {
 678         .owner          = THIS_MODULE,
 679         .llseek         = no_llseek,
 680         .write          = pcwd_write,
 681         .ioctl          = pcwd_ioctl,
 682         .open           = pcwd_open,
 683         .release        = pcwd_close,
 684 };
 685
 686 static struct miscdevice pcwd_miscdev = {
 687         .minor =        WATCHDOG_MINOR,
 688         .name =         "watchdog",
 689         .fops =         &pcwd_fops,
 690 };
 691
 692 static struct file_operations pcwd_temp_fops = {
 693         .owner          = THIS_MODULE,
 694         .llseek         = no_llseek,
 695         .read           = pcwd_temp_read,
 696         .open           = pcwd_temp_open,
 697         .release        = pcwd_temp_close,
 698 };
 699
 700 static struct miscdevice temp_miscdev = {
 701         .minor =        TEMP_MINOR,
 702         .name =         "temperature",
 703         .fops =         &pcwd_temp_fops,
 704 };
 705
 706 static struct notifier_block pcwd_notifier = {
 707         .notifier_call =        pcwd_notify_sys,
 708 };
 709
 710 /*
 711  *      Init & exit routines
 712  */
 713
 714 static inline int get_revision(void)
 715 {
 716         int r = PCWD_REVISION_C;
 717
 718         spin_lock(&pcwd_private.io_lock);
 719         /* REV A cards use only 2 io ports; test
 720          * presumes a floating bus reads as 0xff. */
 721         if ((inb(pcwd_private.io_addr + 2) == 0xFF) ||
 722             (inb(pcwd_private.io_addr + 3) == 0xFF))
 723                 r=PCWD_REVISION_A;
 724         spin_unlock(&pcwd_private.io_lock);
 725
 726         return r;
 727 }
 728
 729 static int __devinit pcwatchdog_init(int base_addr)
 730 {
 731         int ret;
 732
 733         cards_found++;
 734         if (cards_found == 1)
 735                 printk(KERN_INFO PFX "v%s Ken Hollis (kenji@bitgate.com)\n", WD_VER);
 736
 737         if (cards_found > 1) {
 738                 printk(KERN_ERR PFX "This driver only supports 1 device\n");
 739                 return -ENODEV;
 740         }
 741
 742         if (base_addr == 0x0000) {
 743                 printk(KERN_ERR PFX "No I/O-Address for card detected\n");
 744                 return -ENODEV;
 745         }
 746         pcwd_private.io_addr = base_addr;
 747
 748         /* Check card's revision */
 749         pcwd_private.revision = get_revision();
 750
 751         if (!request_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4, "PCWD")) {
 752                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 753                         pcwd_private.io_addr);
 754                 pcwd_private.io_addr = 0x0000;
 755                 return -EIO;
 756         }
 757
 758         /* Initial variables */
 759         pcwd_private.supports_temp = 0;
 760         temp_panic = 0;
 761         pcwd_private.boot_status = 0x0000;
 762
 763         /* get the boot_status */
 764         pcwd_get_status(&pcwd_private.boot_status);
 765
 766         /* clear the "card caused reboot" flag */
 767         pcwd_clear_status();
 768
 769         init_timer(&pcwd_private.timer);
 770         pcwd_private.timer.function = pcwd_timer_ping;
 771         pcwd_private.timer.data = 0;
 772
 773         /*  Disable the board  */
 774         pcwd_stop();
 775
 776         /*  Check whether or not the card supports the temperature device */
 777         pcwd_check_temperature_support();
 778
 779         /* Show info about the card itself */
 780         pcwd_show_card_info();
 781
 782         /* Check that the heartbeat value is within it's range ; if not reset to the default */
 783         if (pcwd_set_heartbeat(heartbeat)) {
 784                 pcwd_set_heartbeat(WATCHDOG_HEARTBEAT);
 785                 printk(KERN_INFO PFX "heartbeat value must be 2<=heartbeat<=7200, using %d\n",
 786                         WATCHDOG_HEARTBEAT);
 787         }
 788
 789         ret = register_reboot_notifier(&pcwd_notifier);
 790         if (ret) {
 791                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 792                         ret);
 793                 release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 794                 pcwd_private.io_addr = 0x0000;
 795                 return ret;
 796         }
 797
 798         if (pcwd_private.supports_temp) {
 799                 ret = misc_register(&temp_miscdev);
 800                 if (ret) {
 801                         printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 802                                 TEMP_MINOR, ret);
 803                         unregister_reboot_notifier(&pcwd_notifier);
 804                         release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 805                         pcwd_private.io_addr = 0x0000;
 806                         return ret;
 807                 }
 808         }
 809
 810         ret = misc_register(&pcwd_miscdev);
 811         if (ret) {
 812                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 813                         WATCHDOG_MINOR, ret);
 814                 if (pcwd_private.supports_temp)
 815                         misc_deregister(&temp_miscdev);
 816                 unregister_reboot_notifier(&pcwd_notifier);
 817                 release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 818                 pcwd_private.io_addr = 0x0000;
 819                 return ret;
 820         }
 821
 822         printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
 823                 heartbeat, nowayout);
 824
 825         return 0;
 826 }
 827
 828 static void __devexit pcwatchdog_exit(void)
 829 {
 830         /*  Disable the board  */
 831         if (!nowayout)
 832                 pcwd_stop();
 833
 834         /* Deregister */
 835         misc_deregister(&pcwd_miscdev);
 836         if (pcwd_private.supports_temp)
 837                 misc_deregister(&temp_miscdev);
 838         unregister_reboot_notifier(&pcwd_notifier);
 839         release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 840         pcwd_private.io_addr = 0x0000;
 841         cards_found--;
 842 }
 843
 844 /*
 845  *  The ISA cards have a heartbeat bit in one of the registers, which
 846  *  register is card dependent.  The heartbeat bit is monitored, and if
 847  *  found, is considered proof that a Berkshire card has been found.
 848  *  The initial rate is once per second at board start up, then twice
 849  *  per second for normal operation.
 850  */
 851 static int __init pcwd_checkcard(int base_addr)
 852 {
 853         int port0, last_port0;  /* Reg 0, in case it's REV A */
 854         int port1, last_port1;  /* Register 1 for REV C cards */
 855         int i;
 856         int retval;
 857
 858         if (!request_region (base_addr, 4, "PCWD")) {
 859                 printk (KERN_INFO PFX "Port 0x%04x unavailable\n", base_addr);
 860                 return 0;
 861         }
 862
 863         retval = 0;
 864
 865         port0 = inb_p(base_addr);       /* For REV A boards */
 866         port1 = inb_p(base_addr + 1);   /* For REV C boards */
 867         if (port0 != 0xff || port1 != 0xff) {
 868                 /* Not an 'ff' from a floating bus, so must be a card! */
 869                 for (i = 0; i < 4; ++i) {
 870
 871                         msleep(500);
 872
 873                         last_port0 = port0;
 874                         last_port1 = port1;
 875
 876                         port0 = inb_p(base_addr);
 877                         port1 = inb_p(base_addr + 1);
 878
 879                         /* Has either hearbeat bit changed?  */
 880                         if ((port0 ^ last_port0) & WD_HRTBT ||
 881                             (port1 ^ last_port1) & WD_REVC_HRBT) {
 882                                 retval = 1;
 883                                 break;
 884                         }
 885                 }
 886         }
 887         release_region (base_addr, 4);
 888
 889         return retval;
 890 }
 891
 892 /*
 893  * These are the auto-probe addresses available.
 894  *
 895  * Revision A only uses ports 0x270 and 0x370.  Revision C introduced 0x350.
 896  * Revision A has an address range of 2 addresses, while Revision C has 4.
 897  */
 898 static int pcwd_ioports[] = { 0x270, 0x350, 0x370, 0x000 };
 899
 900 static int __init pcwd_init_module(void)
 901 {
 902         int i, found = 0;
 903
 904         spin_lock_init(&pcwd_private.io_lock);
 905
 906         for (i = 0; pcwd_ioports[i] != 0; i++) {
 907                 if (pcwd_checkcard(pcwd_ioports[i])) {
 908                         if (!(pcwatchdog_init(pcwd_ioports[i])))
 909                                 found++;
 910                 }
 911         }
 912
 913         if (!found) {
 914                 printk (KERN_INFO PFX "No card detected, or port not available\n");
 915                 return -ENODEV;
 916         }
 917
 918         return 0;
 919 }
 920
 921 static void __exit pcwd_cleanup_module(void)
 922 {
 923         if (pcwd_private.io_addr)
 924                 pcwatchdog_exit();
 925         return;
 926 }
 927
 928 module_init(pcwd_init_module);
 929 module_exit(pcwd_cleanup_module);
 930
 931 MODULE_AUTHOR("Ken Hollis <kenji@bitgate.com>");
 932 MODULE_DESCRIPTION("Berkshire ISA-PC Watchdog driver");
 933 MODULE_LICENSE("GPL");
 934 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 935 MODULE_ALIAS_MISCDEV(TEMP_MINOR);