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