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
 152 static void sc1200wdt_stop(void)
 153 {
 154         sc1200wdt_write_data(WDTO, 0);
 155 }
 156
 157
 158 /* This returns the status of the WDO signal, inactive high. */
 159 static inline int sc1200wdt_status(void)
 160 {
 161         unsigned char ret;
 162
 163         sc1200wdt_read_data(WDST, &ret);
 164         /* If the bit is inactive, the watchdog is enabled, so return
 165          * KEEPALIVEPING which is a bit of a kludge because there's nothing
 166          * else for enabled/disabled status
 167          */
 168         return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
 169         /* bits 1 - 7 are undefined */
 170 }
 171
 172
 173 static int sc1200wdt_open(struct inode *inode, struct file *file)
 174 {
 175         /* allow one at a time */
 176         if (test_and_set_bit(0, &open_flag))
 177                 return -EBUSY;
 178
 179         if (timeout > MAX_TIMEOUT)
 180                 timeout = MAX_TIMEOUT;
 181
 182         sc1200wdt_start();
 183         printk(KERN_INFO PFX "Watchdog enabled, timeout = %d min(s)", timeout);
 184
 185         return nonseekable_open(inode, file);
 186 }
 187
 188
 189 static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
 190                                                 unsigned long arg)
 191 {
 192         int new_timeout;
 193         void __user *argp = (void __user *)arg;
 194         int __user *p = argp;
 195         static const struct watchdog_info ident = {
 196                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
 197                                                         WDIOF_MAGICCLOSE,
 198                 .firmware_version = 0,
 199                 .identity = "PC87307/PC97307",
 200         };
 201
 202         switch (cmd) {
 203
 204         case WDIOC_GETSUPPORT:
 205                 if (copy_to_user(argp, &ident, sizeof ident))
 206                         return -EFAULT;
 207                 return 0;
 208
 209         case WDIOC_GETSTATUS:
 210                 return put_user(sc1200wdt_status(), p);
 211
 212         case WDIOC_GETBOOTSTATUS:
 213                 return put_user(0, p);
 214
 215         case WDIOC_KEEPALIVE:
 216                 sc1200wdt_write_data(WDTO, timeout);
 217                 return 0;
 218
 219         case WDIOC_SETTIMEOUT:
 220                 if (get_user(new_timeout, p))
 221                         return -EFAULT;
 222                 /* the API states this is given in secs */
 223                 new_timeout /= 60;
 224                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 225                         return -EINVAL;
 226                 timeout = new_timeout;
 227                 sc1200wdt_write_data(WDTO, timeout);
 228                 /* fall through and return the new timeout */
 229
 230         case WDIOC_GETTIMEOUT:
 231                 return put_user(timeout * 60, p);
 232
 233         case WDIOC_SETOPTIONS:
 234         {
 235                 int options, retval = -EINVAL;
 236
 237                 if (get_user(options, p))
 238                         return -EFAULT;
 239
 240                 if (options & WDIOS_DISABLECARD) {
 241                         sc1200wdt_stop();
 242                         retval = 0;
 243                 }
 244
 245                 if (options & WDIOS_ENABLECARD) {
 246                         sc1200wdt_start();
 247                         retval = 0;
 248                 }
 249
 250                 return retval;
 251         }
 252         default:
 253                 return -ENOTTY;
 254         }
 255 }
 256
 257
 258 static int sc1200wdt_release(struct inode *inode, struct file *file)
 259 {
 260         if (expect_close == 42) {
 261                 sc1200wdt_stop();
 262                 printk(KERN_INFO PFX "Watchdog disabled\n");
 263         } else {
 264                 sc1200wdt_write_data(WDTO, timeout);
 265                 printk(KERN_CRIT PFX
 266                         "Unexpected close!, timeout = %d min(s)\n", timeout);
 267         }
 268         clear_bit(0, &open_flag);
 269         expect_close = 0;
 270
 271         return 0;
 272 }
 273
 274
 275 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
 276                                                 size_t len, loff_t *ppos)
 277 {
 278         if (len) {
 279                 if (!nowayout) {
 280                         size_t i;
 281
 282                         expect_close = 0;
 283
 284                         for (i = 0; i != len; i++) {
 285                                 char c;
 286
 287                                 if (get_user(c, data+i))
 288                                         return -EFAULT;
 289                                 if (c == 'V')
 290                                         expect_close = 42;
 291                         }
 292                 }
 293
 294                 sc1200wdt_write_data(WDTO, timeout);
 295                 return len;
 296         }
 297
 298         return 0;
 299 }
 300
 301
 302 static int sc1200wdt_notify_sys(struct notifier_block *this,
 303                                         unsigned long code, void *unused)
 304 {
 305         if (code == SYS_DOWN || code == SYS_HALT)
 306                 sc1200wdt_stop();
 307
 308         return NOTIFY_DONE;
 309 }
 310
 311
 312 static struct notifier_block sc1200wdt_notifier = {
 313         .notifier_call =        sc1200wdt_notify_sys,
 314 };
 315
 316 static const struct file_operations sc1200wdt_fops = {
 317         .owner          = THIS_MODULE,
 318         .llseek         = no_llseek,
 319         .write          = sc1200wdt_write,
 320         .unlocked_ioctl = sc1200wdt_ioctl,
 321         .open           = sc1200wdt_open,
 322         .release        = sc1200wdt_release,
 323 };
 324
 325 static struct miscdevice sc1200wdt_miscdev = {
 326         .minor          = WATCHDOG_MINOR,
 327         .name           = "watchdog",
 328         .fops           = &sc1200wdt_fops,
 329 };
 330
 331
 332 static int __init sc1200wdt_probe(void)
 333 {
 334         /* The probe works by reading the PMC3 register's default value of 0x0e
 335          * there is one caveat, if the device disables the parallel port or any
 336          * of the UARTs we won't be able to detect it.
 337          * NB. This could be done with accuracy by reading the SID registers,
 338          * but we don't have access to those io regions.
 339          */
 340
 341         unsigned char reg;
 342
 343         sc1200wdt_read_data(PMC3, &reg);
 344         reg &= 0x0f;            /* we don't want the UART busy bits */
 345         return (reg == 0x0e) ? 0 : -ENODEV;
 346 }
 347
 348
 349 #if defined CONFIG_PNP
 350
 351 static struct pnp_device_id scl200wdt_pnp_devices[] = {
 352         /* National Semiconductor PC87307/PC97307 watchdog component */
 353         {.id = "NSC0800", .driver_data = 0},
 354         {.id = ""},
 355 };
 356
 357 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
 358                                         const struct pnp_device_id *dev_id)
 359 {
 360         /* this driver only supports one card at a time */
 361         if (wdt_dev || !isapnp)
 362                 return -EBUSY;
 363
 364         wdt_dev = dev;
 365         io = pnp_port_start(wdt_dev, 0);
 366         io_len = pnp_port_len(wdt_dev, 0);
 367
 368         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 369                 printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
 370                 return -EBUSY;
 371         }
 372
 373         printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n",
 374                                                                 io, io_len);
 375         return 0;
 376 }
 377
 378 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
 379 {
 380         if (wdt_dev) {
 381                 release_region(io, io_len);
 382                 wdt_dev = NULL;
 383         }
 384 }
 385
 386 static struct pnp_driver scl200wdt_pnp_driver = {
 387         .name           = "scl200wdt",
 388         .id_table       = scl200wdt_pnp_devices,
 389         .probe          = scl200wdt_pnp_probe,
 390         .remove         = scl200wdt_pnp_remove,
 391 };
 392
 393 #endif /* CONFIG_PNP */
 394
 395
 396 static int __init sc1200wdt_init(void)
 397 {
 398         int ret;
 399
 400         printk("%s\n", banner);
 401
 402 #if defined CONFIG_PNP
 403         if (isapnp) {
 404                 ret = pnp_register_driver(&scl200wdt_pnp_driver);
 405                 if (ret)
 406                         goto out_clean;
 407         }
 408 #endif
 409
 410         if (io == -1) {
 411                 printk(KERN_ERR PFX "io parameter must be specified\n");
 412                 ret = -EINVAL;
 413                 goto out_pnp;
 414         }
 415
 416 #if defined CONFIG_PNP
 417         /* now that the user has specified an IO port and we haven't detected
 418          * any devices, disable pnp support */
 419         isapnp = 0;
 420         pnp_unregister_driver(&scl200wdt_pnp_driver);
 421 #endif
 422
 423         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 424                 printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
 425                 ret = -EBUSY;
 426                 goto out_pnp;
 427         }
 428
 429         ret = sc1200wdt_probe();
 430         if (ret)
 431                 goto out_io;
 432
 433         ret = register_reboot_notifier(&sc1200wdt_notifier);
 434         if (ret) {
 435                 printk(KERN_ERR PFX
 436                         "Unable to register reboot notifier err = %d\n", ret);
 437                 goto out_io;
 438         }
 439
 440         ret = misc_register(&sc1200wdt_miscdev);
 441         if (ret) {
 442                 printk(KERN_ERR PFX
 443                         "Unable to register miscdev on minor %d\n",
 444                                                         WATCHDOG_MINOR);
 445                 goto out_rbt;
 446         }
 447
 448         /* ret = 0 */
 449
 450 out_clean:
 451         return ret;
 452
 453 out_rbt:
 454         unregister_reboot_notifier(&sc1200wdt_notifier);
 455
 456 out_io:
 457         release_region(io, io_len);
 458
 459 out_pnp:
 460 #if defined CONFIG_PNP
 461         if (isapnp)
 462                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 463 #endif
 464         goto out_clean;
 465 }
 466
 467
 468 static void __exit sc1200wdt_exit(void)
 469 {
 470         misc_deregister(&sc1200wdt_miscdev);
 471         unregister_reboot_notifier(&sc1200wdt_notifier);
 472
 473 #if defined CONFIG_PNP
 474         if (isapnp)
 475                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 476         else
 477 #endif
 478         release_region(io, io_len);
 479 }
 480
 481 module_init(sc1200wdt_init);
 482 module_exit(sc1200wdt_exit);
 483
 484 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
 485 MODULE_DESCRIPTION("Driver for National Semiconductor PC87307/PC97307 watchdog component");
 486 MODULE_LICENSE("GPL");
 487 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);