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 "1.17"
  77 #define WATCHDOG_DATE "12 Feb 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 #define WD_REVC_RL2A            0x08    /* Relay 2 activated by on-board processor */
 109 #define WD_REVC_RL1A            0x10    /* Relay 1 active */
 110 #define WD_REVC_R2DS            0x40    /* Relay 2 disable */
 111 #define WD_REVC_RLY2            0x80    /* Relay 2 activated? */
 112 /* Port 2 : Control Status #2 */
 113 #define WD_WDIS                 0x10    /* Watchdog Disabled */
 114 #define WD_ENTP                 0x20    /* Watchdog Enable Temperature Trip */
 115 #define WD_SSEL                 0x40    /* Watchdog Switch Select (1:SW1 <-> 0:SW2) */
 116 #define WD_WCMD                 0x80    /* Watchdog Command Mode */
 117
 118 /* max. time we give an ISA watchdog card to process a command */
 119 /* 500ms for each 4 bit response (according to spec.) */
 120 #define ISA_COMMAND_TIMEOUT     1000
 121
 122 /* Watchdog's internal commands */
 123 #define CMD_ISA_IDLE                    0x00
 124 #define CMD_ISA_VERSION_INTEGER         0x01
 125 #define CMD_ISA_VERSION_TENTH           0x02
 126 #define CMD_ISA_VERSION_HUNDRETH        0x03
 127 #define CMD_ISA_VERSION_MINOR           0x04
 128 #define CMD_ISA_SWITCH_SETTINGS         0x05
 129 #define CMD_ISA_DELAY_TIME_2SECS        0x0A
 130 #define CMD_ISA_DELAY_TIME_4SECS        0x0B
 131 #define CMD_ISA_DELAY_TIME_8SECS        0x0C
 132
 133 /*
 134  * We are using an kernel timer to do the pinging of the watchdog
 135  * every ~500ms. We try to set the internal heartbeat of the
 136  * watchdog to 2 ms.
 137  */
 138
 139 #define WDT_INTERVAL (HZ/2+1)
 140
 141 /* We can only use 1 card due to the /dev/watchdog restriction */
 142 static int cards_found;
 143
 144 /* internal variables */
 145 static atomic_t open_allowed = ATOMIC_INIT(1);
 146 static char expect_close;
 147 static int temp_panic;
 148 static struct {                         /* this is private data for each ISA-PC watchdog card */
 149         char fw_ver_str[6];             /* The cards firmware version */
 150         int revision;                   /* The card's revision */
 151         int supports_temp;              /* Wether or not the card has a temperature device */
 152         int command_mode;               /* Wether or not the card is in command mode */
 153         int boot_status;                /* The card's boot status */
 154         int io_addr;                    /* The cards I/O address */
 155         spinlock_t io_lock;             /* the lock for io operations */
 156         struct timer_list timer;        /* The timer that pings the watchdog */
 157         unsigned long next_heartbeat;   /* the next_heartbeat for the timer */
 158 } pcwd_private;
 159
 160 /* module parameters */
 161 #define WATCHDOG_HEARTBEAT 60           /* 60 sec default heartbeat */
 162 static int heartbeat = WATCHDOG_HEARTBEAT;
 163 module_param(heartbeat, int, 0);
 164 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<=heartbeat<=7200, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
 165
 166 static int nowayout = WATCHDOG_NOWAYOUT;
 167 module_param(nowayout, int, 0);
 168 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
 169
 170 /*
 171  *      Internal functions
 172  */
 173
 174 static int send_isa_command(int cmd)
 175 {
 176         int i;
 177         int control_status;
 178         int port0, last_port0;  /* Double read for stabilising */
 179
 180         /* The WCMD bit must be 1 and the command is only 4 bits in size */
 181         control_status = (cmd & 0x0F) | WD_WCMD;
 182         outb_p(control_status, pcwd_private.io_addr + 2);
 183         udelay(ISA_COMMAND_TIMEOUT);
 184
 185         port0 = inb_p(pcwd_private.io_addr);
 186         for (i = 0; i < 25; ++i) {
 187                 last_port0 = port0;
 188                 port0 = inb_p(pcwd_private.io_addr);
 189
 190                 if (port0 == last_port0)
 191                         break;  /* Data is stable */
 192
 193                 udelay (250);
 194         }
 195
 196         return port0;
 197 }
 198
 199 static int set_command_mode(void)
 200 {
 201         int i, found=0, count=0;
 202
 203         /* Set the card into command mode */
 204         spin_lock(&pcwd_private.io_lock);
 205         while ((!found) && (count < 3)) {
 206                 i = send_isa_command(CMD_ISA_IDLE);
 207
 208                 if (i == 0x00)
 209                         found = 1;
 210                 else if (i == 0xF3) {
 211                         /* Card does not like what we've done to it */
 212                         outb_p(0x00, pcwd_private.io_addr + 2);
 213                         udelay(1200);   /* Spec says wait 1ms */
 214                         outb_p(0x00, pcwd_private.io_addr + 2);
 215                         udelay(ISA_COMMAND_TIMEOUT);
 216                 }
 217                 count++;
 218         }
 219         spin_unlock(&pcwd_private.io_lock);
 220         pcwd_private.command_mode = found;
 221
 222         return(found);
 223 }
 224
 225 static void unset_command_mode(void)
 226 {
 227         /* Set the card into normal mode */
 228         spin_lock(&pcwd_private.io_lock);
 229         outb_p(0x00, pcwd_private.io_addr + 2);
 230         udelay(ISA_COMMAND_TIMEOUT);
 231         spin_unlock(&pcwd_private.io_lock);
 232
 233         pcwd_private.command_mode = 0;
 234 }
 235
 236 static inline void pcwd_check_temperature_support(void)
 237 {
 238         if (inb(pcwd_private.io_addr) != 0xF0)
 239                 pcwd_private.supports_temp = 1;
 240 }
 241
 242 static inline void pcwd_get_firmware(void)
 243 {
 244         int one, ten, hund, minor;
 245
 246         sprintf(pcwd_private.fw_ver_str, "ERROR");
 247
 248         if (set_command_mode()) {
 249                 one = send_isa_command(CMD_ISA_VERSION_INTEGER);
 250                 ten = send_isa_command(CMD_ISA_VERSION_TENTH);
 251                 hund = send_isa_command(CMD_ISA_VERSION_HUNDRETH);
 252                 minor = send_isa_command(CMD_ISA_VERSION_MINOR);
 253                 sprintf(pcwd_private.fw_ver_str, "%c.%c%c%c", one, ten, hund, minor);
 254         }
 255         unset_command_mode();
 256
 257         return;
 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         int option_switches;
 276
 277         /* Get some extra info from the hardware (in command/debug/diag mode) */
 278         if (pcwd_private.revision == PCWD_REVISION_A)
 279                 printk(KERN_INFO PFX "ISA-PC Watchdog (REV.A) detected at port 0x%04x\n", pcwd_private.io_addr);
 280         else if (pcwd_private.revision == PCWD_REVISION_C) {
 281                 pcwd_get_firmware();
 282                 printk(KERN_INFO PFX "ISA-PC Watchdog (REV.C) detected at port 0x%04x (Firmware version: %s)\n",
 283                         pcwd_private.io_addr, pcwd_private.fw_ver_str);
 284                 option_switches = pcwd_get_option_switches();
 285                 printk(KERN_INFO PFX "Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
 286                         option_switches,
 287                         ((option_switches & 0x10) ? "ON" : "OFF"),
 288                         ((option_switches & 0x08) ? "ON" : "OFF"));
 289
 290                 /* Reprogram internal heartbeat to 2 seconds */
 291                 if (set_command_mode()) {
 292                         send_isa_command(CMD_ISA_DELAY_TIME_2SECS);
 293                         unset_command_mode();
 294                 }
 295         }
 296
 297         if (pcwd_private.supports_temp)
 298                 printk(KERN_INFO PFX "Temperature Option Detected\n");
 299
 300         if (pcwd_private.boot_status & WDIOF_CARDRESET)
 301                 printk(KERN_INFO PFX "Previous reboot was caused by the card\n");
 302
 303         if (pcwd_private.boot_status & WDIOF_OVERHEAT) {
 304                 printk(KERN_EMERG PFX "Card senses a CPU Overheat. Panicking!\n");
 305                 printk(KERN_EMERG PFX "CPU Overheat\n");
 306         }
 307
 308         if (pcwd_private.boot_status == 0)
 309                 printk(KERN_INFO PFX "No previous trip detected - Cold boot or reset\n");
 310 }
 311
 312 static void pcwd_timer_ping(unsigned long data)
 313 {
 314         int wdrst_stat;
 315
 316         /* If we got a heartbeat pulse within the WDT_INTERVAL
 317          * we agree to ping the WDT */
 318         if(time_before(jiffies, pcwd_private.next_heartbeat)) {
 319                 /* Ping the watchdog */
 320                 spin_lock(&pcwd_private.io_lock);
 321                 if (pcwd_private.revision == PCWD_REVISION_A) {
 322                         /*  Rev A cards are reset by setting the WD_WDRST bit in register 1 */
 323                         wdrst_stat = inb_p(pcwd_private.io_addr);
 324                         wdrst_stat &= 0x0F;
 325                         wdrst_stat |= WD_WDRST;
 326
 327                         outb_p(wdrst_stat, pcwd_private.io_addr + 1);
 328                 } else {
 329                         /* Re-trigger watchdog by writing to port 0 */
 330                         outb_p(0x00, pcwd_private.io_addr);
 331                 }
 332
 333                 /* Re-set the timer interval */
 334                 mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
 335
 336                 spin_unlock(&pcwd_private.io_lock);
 337         } else {
 338                 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
 339         }
 340 }
 341
 342 static int pcwd_start(void)
 343 {
 344         int stat_reg;
 345
 346         pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
 347
 348         /* Start the timer */
 349         mod_timer(&pcwd_private.timer, jiffies + WDT_INTERVAL);
 350
 351         /* Enable the port */
 352         if (pcwd_private.revision == PCWD_REVISION_C) {
 353                 spin_lock(&pcwd_private.io_lock);
 354                 outb_p(0x00, pcwd_private.io_addr + 3);
 355                 udelay(ISA_COMMAND_TIMEOUT);
 356                 stat_reg = inb_p(pcwd_private.io_addr + 2);
 357                 spin_unlock(&pcwd_private.io_lock);
 358                 if (stat_reg & WD_WDIS) {
 359                         printk(KERN_INFO PFX "Could not start watchdog\n");
 360                         return -EIO;
 361                 }
 362         }
 363         return 0;
 364 }
 365
 366 static int pcwd_stop(void)
 367 {
 368         int stat_reg;
 369
 370         /* Stop the timer */
 371         del_timer(&pcwd_private.timer);
 372
 373         /*  Disable the board  */
 374         if (pcwd_private.revision == PCWD_REVISION_C) {
 375                 spin_lock(&pcwd_private.io_lock);
 376                 outb_p(0xA5, pcwd_private.io_addr + 3);
 377                 udelay(ISA_COMMAND_TIMEOUT);
 378                 outb_p(0xA5, pcwd_private.io_addr + 3);
 379                 udelay(ISA_COMMAND_TIMEOUT);
 380                 stat_reg = inb_p(pcwd_private.io_addr + 2);
 381                 spin_unlock(&pcwd_private.io_lock);
 382                 if ((stat_reg & WD_WDIS) == 0) {
 383                         printk(KERN_INFO PFX "Could not stop watchdog\n");
 384                         return -EIO;
 385                 }
 386         }
 387         return 0;
 388 }
 389
 390 static int pcwd_keepalive(void)
 391 {
 392         /* user land ping */
 393         pcwd_private.next_heartbeat = jiffies + (heartbeat * HZ);
 394         return 0;
 395 }
 396
 397 static int pcwd_set_heartbeat(int t)
 398 {
 399         if ((t < 2) || (t > 7200)) /* arbitrary upper limit */
 400                 return -EINVAL;
 401
 402         heartbeat = t;
 403         return 0;
 404 }
 405
 406 static int pcwd_get_status(int *status)
 407 {
 408         int control_status;
 409
 410         *status=0;
 411         spin_lock(&pcwd_private.io_lock);
 412         if (pcwd_private.revision == PCWD_REVISION_A)
 413                 /* Rev A cards return status information from
 414                  * the base register, which is used for the
 415                  * temperature in other cards. */
 416                 control_status = inb(pcwd_private.io_addr);
 417         else {
 418                 /* Rev C cards return card status in the base
 419                  * address + 1 register. And use different bits
 420                  * to indicate a card initiated reset, and an
 421                  * over-temperature condition. And the reboot
 422                  * status can be reset. */
 423                 control_status = inb(pcwd_private.io_addr + 1);
 424         }
 425         spin_unlock(&pcwd_private.io_lock);
 426
 427         if (pcwd_private.revision == PCWD_REVISION_A) {
 428                 if (control_status & WD_WDRST)
 429                         *status |= WDIOF_CARDRESET;
 430
 431                 if (control_status & WD_T110) {
 432                         *status |= WDIOF_OVERHEAT;
 433                         if (temp_panic) {
 434                                 printk (KERN_INFO PFX "Temperature overheat trip!\n");
 435                                 kernel_power_off();
 436                         }
 437                 }
 438         } else {
 439                 if (control_status & WD_REVC_WTRP)
 440                         *status |= WDIOF_CARDRESET;
 441
 442                 if (control_status & WD_REVC_TTRP) {
 443                         *status |= WDIOF_OVERHEAT;
 444                         if (temp_panic) {
 445                                 printk (KERN_INFO PFX "Temperature overheat trip!\n");
 446                                 kernel_power_off();
 447                         }
 448                 }
 449         }
 450
 451         return 0;
 452 }
 453
 454 static int pcwd_clear_status(void)
 455 {
 456         int control_status;
 457
 458         if (pcwd_private.revision == PCWD_REVISION_C) {
 459                 spin_lock(&pcwd_private.io_lock);
 460
 461                 control_status = inb_p(pcwd_private.io_addr + 1);
 462
 463                 /* clear reset status & Keep Relay 2 disable state as it is */
 464                 outb_p((control_status & WD_REVC_R2DS), pcwd_private.io_addr + 1);
 465
 466                 spin_unlock(&pcwd_private.io_lock);
 467         }
 468         return 0;
 469 }
 470
 471 static int pcwd_get_temperature(int *temperature)
 472 {
 473         /* check that port 0 gives temperature info and no command results */
 474         if (pcwd_private.command_mode)
 475                 return -1;
 476
 477         *temperature = 0;
 478         if (!pcwd_private.supports_temp)
 479                 return -ENODEV;
 480
 481         /*
 482          * Convert celsius to fahrenheit, since this was
 483          * the decided 'standard' for this return value.
 484          */
 485         spin_lock(&pcwd_private.io_lock);
 486         *temperature = ((inb(pcwd_private.io_addr)) * 9 / 5) + 32;
 487         spin_unlock(&pcwd_private.io_lock);
 488
 489         return 0;
 490 }
 491
 492 /*
 493  *      /dev/watchdog handling
 494  */
 495
 496 static int pcwd_ioctl(struct inode *inode, struct file *file,
 497                       unsigned int cmd, unsigned long arg)
 498 {
 499         int rv;
 500         int status;
 501         int temperature;
 502         int new_heartbeat;
 503         int __user *argp = (int __user *)arg;
 504         static struct watchdog_info ident = {
 505                 .options =              WDIOF_OVERHEAT |
 506                                         WDIOF_CARDRESET |
 507                                         WDIOF_KEEPALIVEPING |
 508                                         WDIOF_SETTIMEOUT |
 509                                         WDIOF_MAGICCLOSE,
 510                 .firmware_version =     1,
 511                 .identity =             "PCWD",
 512         };
 513
 514         switch(cmd) {
 515         default:
 516                 return -ENOIOCTLCMD;
 517
 518         case WDIOC_GETSUPPORT:
 519                 if(copy_to_user(argp, &ident, sizeof(ident)))
 520                         return -EFAULT;
 521                 return 0;
 522
 523         case WDIOC_GETSTATUS:
 524                 pcwd_get_status(&status);
 525                 return put_user(status, argp);
 526
 527         case WDIOC_GETBOOTSTATUS:
 528                 return put_user(pcwd_private.boot_status, argp);
 529
 530         case WDIOC_GETTEMP:
 531                 if (pcwd_get_temperature(&temperature))
 532                         return -EFAULT;
 533
 534                 return put_user(temperature, argp);
 535
 536         case WDIOC_SETOPTIONS:
 537                 if (pcwd_private.revision == PCWD_REVISION_C)
 538                 {
 539                         if(copy_from_user(&rv, argp, sizeof(int)))
 540                                 return -EFAULT;
 541
 542                         if (rv & WDIOS_DISABLECARD)
 543                         {
 544                                 return pcwd_stop();
 545                         }
 546
 547                         if (rv & WDIOS_ENABLECARD)
 548                         {
 549                                 return pcwd_start();
 550                         }
 551
 552                         if (rv & WDIOS_TEMPPANIC)
 553                         {
 554                                 temp_panic = 1;
 555                         }
 556                 }
 557                 return -EINVAL;
 558
 559         case WDIOC_KEEPALIVE:
 560                 pcwd_keepalive();
 561                 return 0;
 562
 563         case WDIOC_SETTIMEOUT:
 564                 if (get_user(new_heartbeat, argp))
 565                         return -EFAULT;
 566
 567                 if (pcwd_set_heartbeat(new_heartbeat))
 568                         return -EINVAL;
 569
 570                 pcwd_keepalive();
 571                 /* Fall */
 572
 573         case WDIOC_GETTIMEOUT:
 574                 return put_user(heartbeat, argp);
 575         }
 576
 577         return 0;
 578 }
 579
 580 static ssize_t pcwd_write(struct file *file, const char __user *buf, size_t len,
 581                           loff_t *ppos)
 582 {
 583         if (len) {
 584                 if (!nowayout) {
 585                         size_t i;
 586
 587                         /* In case it was set long ago */
 588                         expect_close = 0;
 589
 590                         for (i = 0; i != len; i++) {
 591                                 char c;
 592
 593                                 if (get_user(c, buf + i))
 594                                         return -EFAULT;
 595                                 if (c == 'V')
 596                                         expect_close = 42;
 597                         }
 598                 }
 599                 pcwd_keepalive();
 600         }
 601         return len;
 602 }
 603
 604 static int pcwd_open(struct inode *inode, struct file *file)
 605 {
 606         if (!atomic_dec_and_test(&open_allowed) ) {
 607                 atomic_inc( &open_allowed );
 608                 return -EBUSY;
 609         }
 610
 611         if (nowayout)
 612                 __module_get(THIS_MODULE);
 613
 614         /* Activate */
 615         pcwd_start();
 616         pcwd_keepalive();
 617         return nonseekable_open(inode, file);
 618 }
 619
 620 static int pcwd_close(struct inode *inode, struct file *file)
 621 {
 622         if (expect_close == 42) {
 623                 pcwd_stop();
 624         } else {
 625                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 626                 pcwd_keepalive();
 627         }
 628         expect_close = 0;
 629         atomic_inc( &open_allowed );
 630         return 0;
 631 }
 632
 633 /*
 634  *      /dev/temperature handling
 635  */
 636
 637 static ssize_t pcwd_temp_read(struct file *file, char __user *buf, size_t count,
 638                          loff_t *ppos)
 639 {
 640         int temperature;
 641
 642         if (pcwd_get_temperature(&temperature))
 643                 return -EFAULT;
 644
 645         if (copy_to_user(buf, &temperature, 1))
 646                 return -EFAULT;
 647
 648         return 1;
 649 }
 650
 651 static int pcwd_temp_open(struct inode *inode, struct file *file)
 652 {
 653         if (!pcwd_private.supports_temp)
 654                 return -ENODEV;
 655
 656         return nonseekable_open(inode, file);
 657 }
 658
 659 static int pcwd_temp_close(struct inode *inode, struct file *file)
 660 {
 661         return 0;
 662 }
 663
 664 /*
 665  *      Notify system
 666  */
 667
 668 static int pcwd_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
 669 {
 670         if (code==SYS_DOWN || code==SYS_HALT) {
 671                 /* Turn the WDT off */
 672                 pcwd_stop();
 673         }
 674
 675         return NOTIFY_DONE;
 676 }
 677
 678 /*
 679  *      Kernel Interfaces
 680  */
 681
 682 static struct file_operations pcwd_fops = {
 683         .owner          = THIS_MODULE,
 684         .llseek         = no_llseek,
 685         .write          = pcwd_write,
 686         .ioctl          = pcwd_ioctl,
 687         .open           = pcwd_open,
 688         .release        = pcwd_close,
 689 };
 690
 691 static struct miscdevice pcwd_miscdev = {
 692         .minor =        WATCHDOG_MINOR,
 693         .name =         "watchdog",
 694         .fops =         &pcwd_fops,
 695 };
 696
 697 static struct file_operations pcwd_temp_fops = {
 698         .owner          = THIS_MODULE,
 699         .llseek         = no_llseek,
 700         .read           = pcwd_temp_read,
 701         .open           = pcwd_temp_open,
 702         .release        = pcwd_temp_close,
 703 };
 704
 705 static struct miscdevice temp_miscdev = {
 706         .minor =        TEMP_MINOR,
 707         .name =         "temperature",
 708         .fops =         &pcwd_temp_fops,
 709 };
 710
 711 static struct notifier_block pcwd_notifier = {
 712         .notifier_call =        pcwd_notify_sys,
 713 };
 714
 715 /*
 716  *      Init & exit routines
 717  */
 718
 719 static inline int get_revision(void)
 720 {
 721         int r = PCWD_REVISION_C;
 722
 723         spin_lock(&pcwd_private.io_lock);
 724         /* REV A cards use only 2 io ports; test
 725          * presumes a floating bus reads as 0xff. */
 726         if ((inb(pcwd_private.io_addr + 2) == 0xFF) ||
 727             (inb(pcwd_private.io_addr + 3) == 0xFF))
 728                 r=PCWD_REVISION_A;
 729         spin_unlock(&pcwd_private.io_lock);
 730
 731         return r;
 732 }
 733
 734 static int __devinit pcwatchdog_init(int base_addr)
 735 {
 736         int ret;
 737
 738         cards_found++;
 739         if (cards_found == 1)
 740                 printk(KERN_INFO PFX "v%s Ken Hollis (kenji@bitgate.com)\n", WD_VER);
 741
 742         if (cards_found > 1) {
 743                 printk(KERN_ERR PFX "This driver only supports 1 device\n");
 744                 return -ENODEV;
 745         }
 746
 747         if (base_addr == 0x0000) {
 748                 printk(KERN_ERR PFX "No I/O-Address for card detected\n");
 749                 return -ENODEV;
 750         }
 751         pcwd_private.io_addr = base_addr;
 752
 753         /* Check card's revision */
 754         pcwd_private.revision = get_revision();
 755
 756         if (!request_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4, "PCWD")) {
 757                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 758                         pcwd_private.io_addr);
 759                 pcwd_private.io_addr = 0x0000;
 760                 return -EIO;
 761         }
 762
 763         /* Initial variables */
 764         pcwd_private.supports_temp = 0;
 765         temp_panic = 0;
 766         pcwd_private.boot_status = 0x0000;
 767
 768         /* get the boot_status */
 769         pcwd_get_status(&pcwd_private.boot_status);
 770
 771         /* clear the "card caused reboot" flag */
 772         pcwd_clear_status();
 773
 774         init_timer(&pcwd_private.timer);
 775         pcwd_private.timer.function = pcwd_timer_ping;
 776         pcwd_private.timer.data = 0;
 777
 778         /*  Disable the board  */
 779         pcwd_stop();
 780
 781         /*  Check whether or not the card supports the temperature device */
 782         pcwd_check_temperature_support();
 783
 784         /* Show info about the card itself */
 785         pcwd_show_card_info();
 786
 787         /* Check that the heartbeat value is within it's range ; if not reset to the default */
 788         if (pcwd_set_heartbeat(heartbeat)) {
 789                 pcwd_set_heartbeat(WATCHDOG_HEARTBEAT);
 790                 printk(KERN_INFO PFX "heartbeat value must be 2<=heartbeat<=7200, using %d\n",
 791                         WATCHDOG_HEARTBEAT);
 792         }
 793
 794         ret = register_reboot_notifier(&pcwd_notifier);
 795         if (ret) {
 796                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 797                         ret);
 798                 release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 799                 pcwd_private.io_addr = 0x0000;
 800                 return ret;
 801         }
 802
 803         if (pcwd_private.supports_temp) {
 804                 ret = misc_register(&temp_miscdev);
 805                 if (ret) {
 806                         printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 807                                 TEMP_MINOR, ret);
 808                         unregister_reboot_notifier(&pcwd_notifier);
 809                         release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 810                         pcwd_private.io_addr = 0x0000;
 811                         return ret;
 812                 }
 813         }
 814
 815         ret = misc_register(&pcwd_miscdev);
 816         if (ret) {
 817                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 818                         WATCHDOG_MINOR, ret);
 819                 if (pcwd_private.supports_temp)
 820                         misc_deregister(&temp_miscdev);
 821                 unregister_reboot_notifier(&pcwd_notifier);
 822                 release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 823                 pcwd_private.io_addr = 0x0000;
 824                 return ret;
 825         }
 826
 827         printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
 828                 heartbeat, nowayout);
 829
 830         return 0;
 831 }
 832
 833 static void __devexit pcwatchdog_exit(void)
 834 {
 835         /*  Disable the board  */
 836         if (!nowayout)
 837                 pcwd_stop();
 838
 839         /* Deregister */
 840         misc_deregister(&pcwd_miscdev);
 841         if (pcwd_private.supports_temp)
 842                 misc_deregister(&temp_miscdev);
 843         unregister_reboot_notifier(&pcwd_notifier);
 844         release_region(pcwd_private.io_addr, (pcwd_private.revision == PCWD_REVISION_A) ? 2 : 4);
 845         pcwd_private.io_addr = 0x0000;
 846         cards_found--;
 847 }
 848
 849 /*
 850  *  The ISA cards have a heartbeat bit in one of the registers, which
 851  *  register is card dependent.  The heartbeat bit is monitored, and if
 852  *  found, is considered proof that a Berkshire card has been found.
 853  *  The initial rate is once per second at board start up, then twice
 854  *  per second for normal operation.
 855  */
 856 static int __init pcwd_checkcard(int base_addr)
 857 {
 858         int port0, last_port0;  /* Reg 0, in case it's REV A */
 859         int port1, last_port1;  /* Register 1 for REV C cards */
 860         int i;
 861         int retval;
 862
 863         if (!request_region (base_addr, 4, "PCWD")) {
 864                 printk (KERN_INFO PFX "Port 0x%04x unavailable\n", base_addr);
 865                 return 0;
 866         }
 867
 868         retval = 0;
 869
 870         port0 = inb_p(base_addr);       /* For REV A boards */
 871         port1 = inb_p(base_addr + 1);   /* For REV C boards */
 872         if (port0 != 0xff || port1 != 0xff) {
 873                 /* Not an 'ff' from a floating bus, so must be a card! */
 874                 for (i = 0; i < 4; ++i) {
 875
 876                         msleep(500);
 877
 878                         last_port0 = port0;
 879                         last_port1 = port1;
 880
 881                         port0 = inb_p(base_addr);
 882                         port1 = inb_p(base_addr + 1);
 883
 884                         /* Has either hearbeat bit changed?  */
 885                         if ((port0 ^ last_port0) & WD_HRTBT ||
 886                             (port1 ^ last_port1) & WD_REVC_HRBT) {
 887                                 retval = 1;
 888                                 break;
 889                         }
 890                 }
 891         }
 892         release_region (base_addr, 4);
 893
 894         return retval;
 895 }
 896
 897 /*
 898  * These are the auto-probe addresses available.
 899  *
 900  * Revision A only uses ports 0x270 and 0x370.  Revision C introduced 0x350.
 901  * Revision A has an address range of 2 addresses, while Revision C has 4.
 902  */
 903 static int pcwd_ioports[] = { 0x270, 0x350, 0x370, 0x000 };
 904
 905 static int __init pcwd_init_module(void)
 906 {
 907         int i, found = 0;
 908
 909         spin_lock_init(&pcwd_private.io_lock);
 910
 911         for (i = 0; pcwd_ioports[i] != 0; i++) {
 912                 if (pcwd_checkcard(pcwd_ioports[i])) {
 913                         if (!(pcwatchdog_init(pcwd_ioports[i])))
 914                                 found++;
 915                 }
 916         }
 917
 918         if (!found) {
 919                 printk (KERN_INFO PFX "No card detected, or port not available\n");
 920                 return -ENODEV;
 921         }
 922
 923         return 0;
 924 }
 925
 926 static void __exit pcwd_cleanup_module(void)
 927 {
 928         if (pcwd_private.io_addr)
 929                 pcwatchdog_exit();
 930         return;
 931 }
 932
 933 module_init(pcwd_init_module);
 934 module_exit(pcwd_cleanup_module);
 935
 936 MODULE_AUTHOR("Ken Hollis <kenji@bitgate.com>");
 937 MODULE_DESCRIPTION("Berkshire ISA-PC Watchdog driver");
 938 MODULE_LICENSE("GPL");
 939 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 940 MODULE_ALIAS_MISCDEV(TEMP_MINOR);