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