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 #include <linux/module.h>
  35 #include <linux/moduleparam.h>
  36 #include <linux/miscdevice.h>
  37 #include <linux/watchdog.h>
  38 #include <linux/ioport.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/notifier.h>
  41 #include <linux/reboot.h>
  42 #include <linux/init.h>
  43 #include <linux/pnp.h>
  44 #include <linux/fs.h>
  45 #include <linux/semaphore.h>
  46 #include <linux/io.h>
  47 #include <linux/uaccess.h>
  48
  49 #define SC1200_MODULE_VER       "build 20020303"
  50 #define SC1200_MODULE_NAME      "sc1200wdt"
  51 #define PFX                     SC1200_MODULE_NAME ": "
  52
  53 #define MAX_TIMEOUT     255     /* 255 minutes */
  54 #define PMIR            (io)    /* Power Management Index Register */
  55 #define PMDR            (io+1)  /* Power Management Data Register */
  56
  57 /* Data Register indexes */
  58 #define FER1            0x00    /* Function enable register 1 */
  59 #define FER2            0x01    /* Function enable register 2 */
  60 #define PMC1            0x02    /* Power Management Ctrl 1 */
  61 #define PMC2            0x03    /* Power Management Ctrl 2 */
  62 #define PMC3            0x04    /* Power Management Ctrl 3 */
  63 #define WDTO            0x05    /* Watchdog timeout register */
  64 #define WDCF            0x06    /* Watchdog config register */
  65 #define WDST            0x07    /* Watchdog status register */
  66
  67 /* WDCF bitfields - which devices assert WDO */
  68 #define KBC_IRQ         0x01    /* Keyboard Controller */
  69 #define MSE_IRQ         0x02    /* Mouse */
  70 #define UART1_IRQ       0x03    /* Serial0 */
  71 #define UART2_IRQ       0x04    /* Serial1 */
  72 /* 5 -7 are reserved */
  73
  74 static char banner[] __initdata = KERN_INFO PFX SC1200_MODULE_VER;
  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 int nowayout = WATCHDOG_NOWAYOUT;
  97 module_param(nowayout, int, 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         printk(KERN_INFO PFX "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
 200         case WDIOC_GETSUPPORT:
 201                 if (copy_to_user(argp, &ident, sizeof ident))
 202                         return -EFAULT;
 203                 return 0;
 204
 205         case WDIOC_GETSTATUS:
 206                 return put_user(sc1200wdt_status(), p);
 207
 208         case WDIOC_GETBOOTSTATUS:
 209                 return put_user(0, p);
 210
 211         case WDIOC_KEEPALIVE:
 212                 sc1200wdt_write_data(WDTO, timeout);
 213                 return 0;
 214
 215         case WDIOC_SETTIMEOUT:
 216                 if (get_user(new_timeout, p))
 217                         return -EFAULT;
 218                 /* the API states this is given in secs */
 219                 new_timeout /= 60;
 220                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 221                         return -EINVAL;
 222                 timeout = new_timeout;
 223                 sc1200wdt_write_data(WDTO, timeout);
 224                 /* fall through and return the new timeout */
 225
 226         case WDIOC_GETTIMEOUT:
 227                 return put_user(timeout * 60, p);
 228
 229         case WDIOC_SETOPTIONS:
 230         {
 231                 int options, retval = -EINVAL;
 232
 233                 if (get_user(options, p))
 234                         return -EFAULT;
 235
 236                 if (options & WDIOS_DISABLECARD) {
 237                         sc1200wdt_stop();
 238                         retval = 0;
 239                 }
 240
 241                 if (options & WDIOS_ENABLECARD) {
 242                         sc1200wdt_start();
 243                         retval = 0;
 244                 }
 245
 246                 return retval;
 247         }
 248         default:
 249                 return -ENOTTY;
 250         }
 251 }
 252
 253
 254 static int sc1200wdt_release(struct inode *inode, struct file *file)
 255 {
 256         if (expect_close == 42) {
 257                 sc1200wdt_stop();
 258                 printk(KERN_INFO PFX "Watchdog disabled\n");
 259         } else {
 260                 sc1200wdt_write_data(WDTO, timeout);
 261                 printk(KERN_CRIT PFX
 262                         "Unexpected close!, timeout = %d min(s)\n", timeout);
 263         }
 264         clear_bit(0, &open_flag);
 265         expect_close = 0;
 266
 267         return 0;
 268 }
 269
 270
 271 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
 272                                                 size_t len, loff_t *ppos)
 273 {
 274         if (len) {
 275                 if (!nowayout) {
 276                         size_t i;
 277
 278                         expect_close = 0;
 279
 280                         for (i = 0; i != len; i++) {
 281                                 char c;
 282
 283                                 if (get_user(c, data+i))
 284                                         return -EFAULT;
 285                                 if (c == 'V')
 286                                         expect_close = 42;
 287                         }
 288                 }
 289
 290                 sc1200wdt_write_data(WDTO, timeout);
 291                 return len;
 292         }
 293
 294         return 0;
 295 }
 296
 297
 298 static int sc1200wdt_notify_sys(struct notifier_block *this,
 299                                         unsigned long code, void *unused)
 300 {
 301         if (code == SYS_DOWN || code == SYS_HALT)
 302                 sc1200wdt_stop();
 303
 304         return NOTIFY_DONE;
 305 }
 306
 307
 308 static struct notifier_block sc1200wdt_notifier = {
 309         .notifier_call =        sc1200wdt_notify_sys,
 310 };
 311
 312 static const struct file_operations sc1200wdt_fops = {
 313         .owner          = THIS_MODULE,
 314         .llseek         = no_llseek,
 315         .write          = sc1200wdt_write,
 316         .unlocked_ioctl = sc1200wdt_ioctl,
 317         .open           = sc1200wdt_open,
 318         .release        = sc1200wdt_release,
 319 };
 320
 321 static struct miscdevice sc1200wdt_miscdev = {
 322         .minor          = WATCHDOG_MINOR,
 323         .name           = "watchdog",
 324         .fops           = &sc1200wdt_fops,
 325 };
 326
 327
 328 static int __init sc1200wdt_probe(void)
 329 {
 330         /* The probe works by reading the PMC3 register's default value of 0x0e
 331          * there is one caveat, if the device disables the parallel port or any
 332          * of the UARTs we won't be able to detect it.
 333          * NB. This could be done with accuracy by reading the SID registers,
 334          * but we don't have access to those io regions.
 335          */
 336
 337         unsigned char reg;
 338
 339         sc1200wdt_read_data(PMC3, &reg);
 340         reg &= 0x0f;            /* we don't want the UART busy bits */
 341         return (reg == 0x0e) ? 0 : -ENODEV;
 342 }
 343
 344
 345 #if defined CONFIG_PNP
 346
 347 static struct pnp_device_id scl200wdt_pnp_devices[] = {
 348         /* National Semiconductor PC87307/PC97307 watchdog component */
 349         {.id = "NSC0800", .driver_data = 0},
 350         {.id = ""},
 351 };
 352
 353 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
 354                                         const struct pnp_device_id *dev_id)
 355 {
 356         /* this driver only supports one card at a time */
 357         if (wdt_dev || !isapnp)
 358                 return -EBUSY;
 359
 360         wdt_dev = dev;
 361         io = pnp_port_start(wdt_dev, 0);
 362         io_len = pnp_port_len(wdt_dev, 0);
 363
 364         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 365                 printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
 366                 return -EBUSY;
 367         }
 368
 369         printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n",
 370                                                                 io, io_len);
 371         return 0;
 372 }
 373
 374 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
 375 {
 376         if (wdt_dev) {
 377                 release_region(io, io_len);
 378                 wdt_dev = NULL;
 379         }
 380 }
 381
 382 static struct pnp_driver scl200wdt_pnp_driver = {
 383         .name           = "scl200wdt",
 384         .id_table       = scl200wdt_pnp_devices,
 385         .probe          = scl200wdt_pnp_probe,
 386         .remove         = scl200wdt_pnp_remove,
 387 };
 388
 389 #endif /* CONFIG_PNP */
 390
 391
 392 static int __init sc1200wdt_init(void)
 393 {
 394         int ret;
 395
 396         printk("%s\n", banner);
 397
 398 #if defined CONFIG_PNP
 399         if (isapnp) {
 400                 ret = pnp_register_driver(&scl200wdt_pnp_driver);
 401                 if (ret)
 402                         goto out_clean;
 403         }
 404 #endif
 405
 406         if (io == -1) {
 407                 printk(KERN_ERR PFX "io parameter must be specified\n");
 408                 ret = -EINVAL;
 409                 goto out_pnp;
 410         }
 411
 412 #if defined CONFIG_PNP
 413         /* now that the user has specified an IO port and we haven't detected
 414          * any devices, disable pnp support */
 415         isapnp = 0;
 416         pnp_unregister_driver(&scl200wdt_pnp_driver);
 417 #endif
 418
 419         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 420                 printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
 421                 ret = -EBUSY;
 422                 goto out_pnp;
 423         }
 424
 425         ret = sc1200wdt_probe();
 426         if (ret)
 427                 goto out_io;
 428
 429         ret = register_reboot_notifier(&sc1200wdt_notifier);
 430         if (ret) {
 431                 printk(KERN_ERR PFX
 432                         "Unable to register reboot notifier err = %d\n", ret);
 433                 goto out_io;
 434         }
 435
 436         ret = misc_register(&sc1200wdt_miscdev);
 437         if (ret) {
 438                 printk(KERN_ERR PFX
 439                         "Unable to register miscdev on minor %d\n",
 440                                                         WATCHDOG_MINOR);
 441                 goto out_rbt;
 442         }
 443
 444         /* ret = 0 */
 445
 446 out_clean:
 447         return ret;
 448
 449 out_rbt:
 450         unregister_reboot_notifier(&sc1200wdt_notifier);
 451
 452 out_io:
 453         release_region(io, io_len);
 454
 455 out_pnp:
 456 #if defined CONFIG_PNP
 457         if (isapnp)
 458                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 459 #endif
 460         goto out_clean;
 461 }
 462
 463
 464 static void __exit sc1200wdt_exit(void)
 465 {
 466         misc_deregister(&sc1200wdt_miscdev);
 467         unregister_reboot_notifier(&sc1200wdt_notifier);
 468
 469 #if defined CONFIG_PNP
 470         if (isapnp)
 471                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 472         else
 473 #endif
 474         release_region(io, io_len);
 475 }
 476
 477 module_init(sc1200wdt_init);
 478 module_exit(sc1200wdt_exit);
 479
 480 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
 481 MODULE_DESCRIPTION("Driver for National Semiconductor PC87307/PC97307 watchdog component");
 482 MODULE_LICENSE("GPL");
 483 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);