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