drivers/watchdog/sc1200wdt.c

   1 /*
   2  *      National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
   3  *      (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>,
   4  *                      All Rights Reserved.
   5  *      Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  *
  12  *      The author(s) of this software shall not be held liable for damages
  13  *      of any nature resulting due to the use of this software. This
  14  *      software is provided AS-IS with no warranties.
  15  *
  16  *      Changelog:
  17  *      20020220 Zwane Mwaikambo        Code based on datasheet, no hardware.
  18  *      20020221 Zwane Mwaikambo        Cleanups as suggested by Jeff Garzik
  19  *                                      and Alan Cox.
  20  *      20020222 Zwane Mwaikambo        Added probing.
  21  *      20020225 Zwane Mwaikambo        Added ISAPNP support.
  22  *      20020412 Rob Radez              Broke out start/stop functions
  23  *               <rob@osinvestor.com>   Return proper status instead of
  24  *                                      temperature warning
  25  *                                      Add WDIOC_GETBOOTSTATUS and
  26  *                                      WDIOC_SETOPTIONS ioctls
  27  *                                      Fix CONFIG_WATCHDOG_NOWAYOUT
  28  *      20020530 Joel Becker            Add Matt Domsch's nowayout module
  29  *                                      option
  30  *      20030116 Adam Belay             Updated to the latest pnp code
  31  *
  32  */
  33
  34 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  35
  36 #include <linux/module.h>
  37 #include <linux/moduleparam.h>
  38 #include <linux/miscdevice.h>
  39 #include <linux/watchdog.h>
  40 #include <linux/ioport.h>
  41 #include <linux/spinlock.h>
  42 #include <linux/notifier.h>
  43 #include <linux/reboot.h>
  44 #include <linux/init.h>
  45 #include <linux/pnp.h>
  46 #include <linux/fs.h>
  47 #include <linux/semaphore.h>
  48 #include <linux/io.h>
  49 #include <linux/uaccess.h>
  50
  51 #define SC1200_MODULE_VER       "build 20020303"
  52 #define SC1200_MODULE_NAME      "sc1200wdt"
  53
  54 #define MAX_TIMEOUT     255     /* 255 minutes */
  55 #define PMIR            (io)    /* Power Management Index Register */
  56 #define PMDR            (io+1)  /* Power Management Data Register */
  57
  58 /* Data Register indexes */
  59 #define FER1            0x00    /* Function enable register 1 */
  60 #define FER2            0x01    /* Function enable register 2 */
  61 #define PMC1            0x02    /* Power Management Ctrl 1 */
  62 #define PMC2            0x03    /* Power Management Ctrl 2 */
  63 #define PMC3            0x04    /* Power Management Ctrl 3 */
  64 #define WDTO            0x05    /* Watchdog timeout register */
  65 #define WDCF            0x06    /* Watchdog config register */
  66 #define WDST            0x07    /* Watchdog status register */
  67
  68 /* WDCF bitfields - which devices assert WDO */
  69 #define KBC_IRQ         0x01    /* Keyboard Controller */
  70 #define MSE_IRQ         0x02    /* Mouse */
  71 #define UART1_IRQ       0x03    /* Serial0 */
  72 #define UART2_IRQ       0x04    /* Serial1 */
  73 /* 5 -7 are reserved */
  74
  75 static int timeout = 1;
  76 static int io = -1;
  77 static int io_len = 2;          /* for non plug and play */
  78 static unsigned long open_flag;
  79 static char expect_close;
  80 static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */
  81
  82 #if defined CONFIG_PNP
  83 static int isapnp = 1;
  84 static struct pnp_dev *wdt_dev;
  85
  86 module_param(isapnp, int, 0);
  87 MODULE_PARM_DESC(isapnp,
  88         "When set to 0 driver ISA PnP support will be disabled");
  89 #endif
  90
  91 module_param(io, int, 0);
  92 MODULE_PARM_DESC(io, "io port");
  93 module_param(timeout, int, 0);
  94 MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
  95
  96 static bool nowayout = WATCHDOG_NOWAYOUT;
  97 module_param(nowayout, bool, 0);
  98 MODULE_PARM_DESC(nowayout,
  99         "Watchdog cannot be stopped once started (default="
 100                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 101
 102
 103
 104 /* Read from Data Register */
 105 static inline void __sc1200wdt_read_data(unsigned char index,
 106                                                 unsigned char *data)
 107 {
 108         outb_p(index, PMIR);
 109         *data = inb(PMDR);
 110 }
 111
 112 static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
 113 {
 114         spin_lock(&sc1200wdt_lock);
 115         __sc1200wdt_read_data(index, data);
 116         spin_unlock(&sc1200wdt_lock);
 117 }
 118
 119 /* Write to Data Register */
 120 static inline void __sc1200wdt_write_data(unsigned char index,
 121                                                 unsigned char data)
 122 {
 123         outb_p(index, PMIR);
 124         outb(data, PMDR);
 125 }
 126
 127 static inline void sc1200wdt_write_data(unsigned char index,
 128                                                 unsigned char data)
 129 {
 130         spin_lock(&sc1200wdt_lock);
 131         __sc1200wdt_write_data(index, data);
 132         spin_unlock(&sc1200wdt_lock);
 133 }
 134
 135
 136 static void sc1200wdt_start(void)
 137 {
 138         unsigned char reg;
 139         spin_lock(&sc1200wdt_lock);
 140
 141         __sc1200wdt_read_data(WDCF, &reg);
 142         /* assert WDO when any of the following interrupts are triggered too */
 143         reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
 144         __sc1200wdt_write_data(WDCF, reg);
 145         /* set the timeout and get the ball rolling */
 146         __sc1200wdt_write_data(WDTO, timeout);
 147
 148         spin_unlock(&sc1200wdt_lock);
 149 }
 150
 151 static void sc1200wdt_stop(void)
 152 {
 153         sc1200wdt_write_data(WDTO, 0);
 154 }
 155
 156 /* This returns the status of the WDO signal, inactive high. */
 157 static inline int sc1200wdt_status(void)
 158 {
 159         unsigned char ret;
 160
 161         sc1200wdt_read_data(WDST, &ret);
 162         /* If the bit is inactive, the watchdog is enabled, so return
 163          * KEEPALIVEPING which is a bit of a kludge because there's nothing
 164          * else for enabled/disabled status
 165          */
 166         return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
 167 }
 168
 169 static int sc1200wdt_open(struct inode *inode, struct file *file)
 170 {
 171         /* allow one at a time */
 172         if (test_and_set_bit(0, &open_flag))
 173                 return -EBUSY;
 174
 175         if (timeout > MAX_TIMEOUT)
 176                 timeout = MAX_TIMEOUT;
 177
 178         sc1200wdt_start();
 179         pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
 180
 181         return nonseekable_open(inode, file);
 182 }
 183
 184
 185 static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
 186                                                 unsigned long arg)
 187 {
 188         int new_timeout;
 189         void __user *argp = (void __user *)arg;
 190         int __user *p = argp;
 191         static const struct watchdog_info ident = {
 192                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
 193                                                         WDIOF_MAGICCLOSE,
 194                 .firmware_version = 0,
 195                 .identity = "PC87307/PC97307",
 196         };
 197
 198         switch (cmd) {
 199         case WDIOC_GETSUPPORT:
 200                 if (copy_to_user(argp, &ident, sizeof(ident)))
 201                         return -EFAULT;
 202                 return 0;
 203
 204         case WDIOC_GETSTATUS:
 205                 return put_user(sc1200wdt_status(), p);
 206
 207         case WDIOC_GETBOOTSTATUS:
 208                 return put_user(0, p);
 209
 210         case WDIOC_SETOPTIONS:
 211         {
 212                 int options, retval = -EINVAL;
 213
 214                 if (get_user(options, p))
 215                         return -EFAULT;
 216
 217                 if (options & WDIOS_DISABLECARD) {
 218                         sc1200wdt_stop();
 219                         retval = 0;
 220                 }
 221
 222                 if (options & WDIOS_ENABLECARD) {
 223                         sc1200wdt_start();
 224                         retval = 0;
 225                 }
 226
 227                 return retval;
 228         }
 229         case WDIOC_KEEPALIVE:
 230                 sc1200wdt_write_data(WDTO, timeout);
 231                 return 0;
 232
 233         case WDIOC_SETTIMEOUT:
 234                 if (get_user(new_timeout, p))
 235                         return -EFAULT;
 236                 /* the API states this is given in secs */
 237                 new_timeout /= 60;
 238                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 239                         return -EINVAL;
 240                 timeout = new_timeout;
 241                 sc1200wdt_write_data(WDTO, timeout);
 242                 /* fall through and return the new timeout */
 243
 244         case WDIOC_GETTIMEOUT:
 245                 return put_user(timeout * 60, p);
 246
 247         default:
 248                 return -ENOTTY;
 249         }
 250 }
 251
 252
 253 static int sc1200wdt_release(struct inode *inode, struct file *file)
 254 {
 255         if (expect_close == 42) {
 256                 sc1200wdt_stop();
 257                 pr_info("Watchdog disabled\n");
 258         } else {
 259                 sc1200wdt_write_data(WDTO, timeout);
 260                 pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
 261         }
 262         clear_bit(0, &open_flag);
 263         expect_close = 0;
 264
 265         return 0;
 266 }
 267
 268
 269 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
 270                                                 size_t len, loff_t *ppos)
 271 {
 272         if (len) {
 273                 if (!nowayout) {
 274                         size_t i;
 275
 276                         expect_close = 0;
 277
 278                         for (i = 0; i != len; i++) {
 279                                 char c;
 280
 281                                 if (get_user(c, data + i))
 282                                         return -EFAULT;
 283                                 if (c == 'V')
 284                                         expect_close = 42;
 285                         }
 286                 }
 287
 288                 sc1200wdt_write_data(WDTO, timeout);
 289                 return len;
 290         }
 291
 292         return 0;
 293 }
 294
 295
 296 static int sc1200wdt_notify_sys(struct notifier_block *this,
 297                                         unsigned long code, void *unused)
 298 {
 299         if (code == SYS_DOWN || code == SYS_HALT)
 300                 sc1200wdt_stop();
 301
 302         return NOTIFY_DONE;
 303 }
 304
 305
 306 static struct notifier_block sc1200wdt_notifier = {
 307         .notifier_call =        sc1200wdt_notify_sys,
 308 };
 309
 310 static const struct file_operations sc1200wdt_fops = {
 311         .owner          = THIS_MODULE,
 312         .llseek         = no_llseek,
 313         .write          = sc1200wdt_write,
 314         .unlocked_ioctl = sc1200wdt_ioctl,
 315         .open           = sc1200wdt_open,
 316         .release        = sc1200wdt_release,
 317 };
 318
 319 static struct miscdevice sc1200wdt_miscdev = {
 320         .minor          = WATCHDOG_MINOR,
 321         .name           = "watchdog",
 322         .fops           = &sc1200wdt_fops,
 323 };
 324
 325
 326 static int __init sc1200wdt_probe(void)
 327 {
 328         /* The probe works by reading the PMC3 register's default value of 0x0e
 329          * there is one caveat, if the device disables the parallel port or any
 330          * of the UARTs we won't be able to detect it.
 331          * NB. This could be done with accuracy by reading the SID registers,
 332          * but we don't have access to those io regions.
 333          */
 334
 335         unsigned char reg;
 336
 337         sc1200wdt_read_data(PMC3, &reg);
 338         reg &= 0x0f;            /* we don't want the UART busy bits */
 339         return (reg == 0x0e) ? 0 : -ENODEV;
 340 }
 341
 342
 343 #if defined CONFIG_PNP
 344
 345 static struct pnp_device_id scl200wdt_pnp_devices[] = {
 346         /* National Semiconductor PC87307/PC97307 watchdog component */
 347         {.id = "NSC0800", .driver_data = 0},
 348         {.id = ""},
 349 };
 350
 351 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
 352                                         const struct pnp_device_id *dev_id)
 353 {
 354         /* this driver only supports one card at a time */
 355         if (wdt_dev || !isapnp)
 356                 return -EBUSY;
 357
 358         wdt_dev = dev;
 359         io = pnp_port_start(wdt_dev, 0);
 360         io_len = pnp_port_len(wdt_dev, 0);
 361
 362         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 363                 pr_err("Unable to register IO port %#x\n", io);
 364                 return -EBUSY;
 365         }
 366
 367         pr_info("PnP device found at io port %#x/%d\n", io, io_len);
 368         return 0;
 369 }
 370
 371 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
 372 {
 373         if (wdt_dev) {
 374                 release_region(io, io_len);
 375                 wdt_dev = NULL;
 376         }
 377 }
 378
 379 static struct pnp_driver scl200wdt_pnp_driver = {
 380         .name           = "scl200wdt",
 381         .id_table       = scl200wdt_pnp_devices,
 382         .probe          = scl200wdt_pnp_probe,
 383         .remove         = scl200wdt_pnp_remove,
 384 };
 385
 386 #endif /* CONFIG_PNP */
 387
 388
 389 static int __init sc1200wdt_init(void)
 390 {
 391         int ret;
 392
 393         pr_info("%s\n", SC1200_MODULE_VER);
 394
 395 #if defined CONFIG_PNP
 396         if (isapnp) {
 397                 ret = pnp_register_driver(&scl200wdt_pnp_driver);
 398                 if (ret)
 399                         goto out_clean;
 400         }
 401 #endif
 402
 403         if (io == -1) {
 404                 pr_err("io parameter must be specified\n");
 405                 ret = -EINVAL;
 406                 goto out_pnp;
 407         }
 408
 409 #if defined CONFIG_PNP
 410         /* now that the user has specified an IO port and we haven't detected
 411          * any devices, disable pnp support */
 412         isapnp = 0;
 413         pnp_unregister_driver(&scl200wdt_pnp_driver);
 414 #endif
 415
 416         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 417                 pr_err("Unable to register IO port %#x\n", io);
 418                 ret = -EBUSY;
 419                 goto out_pnp;
 420         }
 421
 422         ret = sc1200wdt_probe();
 423         if (ret)
 424                 goto out_io;
 425
 426         ret = register_reboot_notifier(&sc1200wdt_notifier);
 427         if (ret) {
 428                 pr_err("Unable to register reboot notifier err = %d\n", ret);
 429                 goto out_io;
 430         }
 431
 432         ret = misc_register(&sc1200wdt_miscdev);
 433         if (ret) {
 434                 pr_err("Unable to register miscdev on minor %d\n",
 435                        WATCHDOG_MINOR);
 436                 goto out_rbt;
 437         }
 438
 439         /* ret = 0 */
 440
 441 out_clean:
 442         return ret;
 443
 444 out_rbt:
 445         unregister_reboot_notifier(&sc1200wdt_notifier);
 446
 447 out_io:
 448         release_region(io, io_len);
 449
 450 out_pnp:
 451 #if defined CONFIG_PNP
 452         if (isapnp)
 453                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 454 #endif
 455         goto out_clean;
 456 }
 457
 458
 459 static void __exit sc1200wdt_exit(void)
 460 {
 461         misc_deregister(&sc1200wdt_miscdev);
 462         unregister_reboot_notifier(&sc1200wdt_notifier);
 463
 464 #if defined CONFIG_PNP
 465         if (isapnp)
 466                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 467         else
 468 #endif
 469         release_region(io, io_len);
 470 }
 471
 472 module_init(sc1200wdt_init);
 473 module_exit(sc1200wdt_exit);
 474
 475 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
 476 MODULE_DESCRIPTION(
 477         "Driver for National Semiconductor PC87307/PC97307 watchdog component");
 478 MODULE_LICENSE("GPL");
 479 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);