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 = 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         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                 printk(KERN_INFO PFX "Watchdog disabled\n");
 258         } else {
 259                 sc1200wdt_write_data(WDTO, timeout);
 260                 printk(KERN_CRIT PFX
 261                         "Unexpected close!, timeout = %d min(s)\n", timeout);
 262         }
 263         clear_bit(0, &open_flag);
 264         expect_close = 0;
 265
 266         return 0;
 267 }
 268
 269
 270 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
 271                                                 size_t len, loff_t *ppos)
 272 {
 273         if (len) {
 274                 if (!nowayout) {
 275                         size_t i;
 276
 277                         expect_close = 0;
 278
 279                         for (i = 0; i != len; i++) {
 280                                 char c;
 281
 282                                 if (get_user(c, data + i))
 283                                         return -EFAULT;
 284                                 if (c == 'V')
 285                                         expect_close = 42;
 286                         }
 287                 }
 288
 289                 sc1200wdt_write_data(WDTO, timeout);
 290                 return len;
 291         }
 292
 293         return 0;
 294 }
 295
 296
 297 static int sc1200wdt_notify_sys(struct notifier_block *this,
 298                                         unsigned long code, void *unused)
 299 {
 300         if (code == SYS_DOWN || code == SYS_HALT)
 301                 sc1200wdt_stop();
 302
 303         return NOTIFY_DONE;
 304 }
 305
 306
 307 static struct notifier_block sc1200wdt_notifier = {
 308         .notifier_call =        sc1200wdt_notify_sys,
 309 };
 310
 311 static const struct file_operations sc1200wdt_fops = {
 312         .owner          = THIS_MODULE,
 313         .llseek         = no_llseek,
 314         .write          = sc1200wdt_write,
 315         .unlocked_ioctl = sc1200wdt_ioctl,
 316         .open           = sc1200wdt_open,
 317         .release        = sc1200wdt_release,
 318 };
 319
 320 static struct miscdevice sc1200wdt_miscdev = {
 321         .minor          = WATCHDOG_MINOR,
 322         .name           = "watchdog",
 323         .fops           = &sc1200wdt_fops,
 324 };
 325
 326
 327 static int __init sc1200wdt_probe(void)
 328 {
 329         /* The probe works by reading the PMC3 register's default value of 0x0e
 330          * there is one caveat, if the device disables the parallel port or any
 331          * of the UARTs we won't be able to detect it.
 332          * NB. This could be done with accuracy by reading the SID registers,
 333          * but we don't have access to those io regions.
 334          */
 335
 336         unsigned char reg;
 337
 338         sc1200wdt_read_data(PMC3, &reg);
 339         reg &= 0x0f;            /* we don't want the UART busy bits */
 340         return (reg == 0x0e) ? 0 : -ENODEV;
 341 }
 342
 343
 344 #if defined CONFIG_PNP
 345
 346 static struct pnp_device_id scl200wdt_pnp_devices[] = {
 347         /* National Semiconductor PC87307/PC97307 watchdog component */
 348         {.id = "NSC0800", .driver_data = 0},
 349         {.id = ""},
 350 };
 351
 352 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
 353                                         const struct pnp_device_id *dev_id)
 354 {
 355         /* this driver only supports one card at a time */
 356         if (wdt_dev || !isapnp)
 357                 return -EBUSY;
 358
 359         wdt_dev = dev;
 360         io = pnp_port_start(wdt_dev, 0);
 361         io_len = pnp_port_len(wdt_dev, 0);
 362
 363         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 364                 printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
 365                 return -EBUSY;
 366         }
 367
 368         printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n",
 369                                                                 io, io_len);
 370         return 0;
 371 }
 372
 373 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
 374 {
 375         if (wdt_dev) {
 376                 release_region(io, io_len);
 377                 wdt_dev = NULL;
 378         }
 379 }
 380
 381 static struct pnp_driver scl200wdt_pnp_driver = {
 382         .name           = "scl200wdt",
 383         .id_table       = scl200wdt_pnp_devices,
 384         .probe          = scl200wdt_pnp_probe,
 385         .remove         = scl200wdt_pnp_remove,
 386 };
 387
 388 #endif /* CONFIG_PNP */
 389
 390
 391 static int __init sc1200wdt_init(void)
 392 {
 393         int ret;
 394
 395         printk(KERN_INFO "%s\n", banner);
 396
 397 #if defined CONFIG_PNP
 398         if (isapnp) {
 399                 ret = pnp_register_driver(&scl200wdt_pnp_driver);
 400                 if (ret)
 401                         goto out_clean;
 402         }
 403 #endif
 404
 405         if (io == -1) {
 406                 printk(KERN_ERR PFX "io parameter must be specified\n");
 407                 ret = -EINVAL;
 408                 goto out_pnp;
 409         }
 410
 411 #if defined CONFIG_PNP
 412         /* now that the user has specified an IO port and we haven't detected
 413          * any devices, disable pnp support */
 414         isapnp = 0;
 415         pnp_unregister_driver(&scl200wdt_pnp_driver);
 416 #endif
 417
 418         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 419                 printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
 420                 ret = -EBUSY;
 421                 goto out_pnp;
 422         }
 423
 424         ret = sc1200wdt_probe();
 425         if (ret)
 426                 goto out_io;
 427
 428         ret = register_reboot_notifier(&sc1200wdt_notifier);
 429         if (ret) {
 430                 printk(KERN_ERR PFX
 431                         "Unable to register reboot notifier err = %d\n", ret);
 432                 goto out_io;
 433         }
 434
 435         ret = misc_register(&sc1200wdt_miscdev);
 436         if (ret) {
 437                 printk(KERN_ERR PFX
 438                         "Unable to register miscdev on minor %d\n",
 439                                                         WATCHDOG_MINOR);
 440                 goto out_rbt;
 441         }
 442
 443         /* ret = 0 */
 444
 445 out_clean:
 446         return ret;
 447
 448 out_rbt:
 449         unregister_reboot_notifier(&sc1200wdt_notifier);
 450
 451 out_io:
 452         release_region(io, io_len);
 453
 454 out_pnp:
 455 #if defined CONFIG_PNP
 456         if (isapnp)
 457                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 458 #endif
 459         goto out_clean;
 460 }
 461
 462
 463 static void __exit sc1200wdt_exit(void)
 464 {
 465         misc_deregister(&sc1200wdt_miscdev);
 466         unregister_reboot_notifier(&sc1200wdt_notifier);
 467
 468 #if defined CONFIG_PNP
 469         if (isapnp)
 470                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 471         else
 472 #endif
 473         release_region(io, io_len);
 474 }
 475
 476 module_init(sc1200wdt_init);
 477 module_exit(sc1200wdt_exit);
 478
 479 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
 480 MODULE_DESCRIPTION(
 481         "Driver for National Semiconductor PC87307/PC97307 watchdog component");
 482 MODULE_LICENSE("GPL");
 483 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);