drivers/watchdog/sc1200wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
   4  *      (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>,
   5  *                      All Rights Reserved.
   6  *      Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
   7  *
   8  *      The author(s) of this software shall not be held liable for damages
   9  *      of any nature resulting due to the use of this software. This
  10  *      software is provided AS-IS with no warranties.
  11  *
  12  *      Changelog:
  13  *      20020220 Zwane Mwaikambo        Code based on datasheet, no hardware.
  14  *      20020221 Zwane Mwaikambo        Cleanups as suggested by Jeff Garzik
  15  *                                      and Alan Cox.
  16  *      20020222 Zwane Mwaikambo        Added probing.
  17  *      20020225 Zwane Mwaikambo        Added ISAPNP support.
  18  *      20020412 Rob Radez              Broke out start/stop functions
  19  *               <rob@osinvestor.com>   Return proper status instead of
  20  *                                      temperature warning
  21  *                                      Add WDIOC_GETBOOTSTATUS and
  22  *                                      WDIOC_SETOPTIONS ioctls
  23  *                                      Fix CONFIG_WATCHDOG_NOWAYOUT
  24  *      20020530 Joel Becker            Add Matt Domsch's nowayout module
  25  *                                      option
  26  *      20030116 Adam Belay             Updated to the latest pnp code
  27  */
  28
  29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  30
  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/semaphore.h>
  43 #include <linux/io.h>
  44 #include <linux/uaccess.h>
  45
  46 #define SC1200_MODULE_VER       "build 20020303"
  47 #define SC1200_MODULE_NAME      "sc1200wdt"
  48
  49 #define MAX_TIMEOUT     255     /* 255 minutes */
  50 #define PMIR            (io)    /* Power Management Index Register */
  51 #define PMDR            (io+1)  /* Power Management Data Register */
  52
  53 /* Data Register indexes */
  54 #define FER1            0x00    /* Function enable register 1 */
  55 #define FER2            0x01    /* Function enable register 2 */
  56 #define PMC1            0x02    /* Power Management Ctrl 1 */
  57 #define PMC2            0x03    /* Power Management Ctrl 2 */
  58 #define PMC3            0x04    /* Power Management Ctrl 3 */
  59 #define WDTO            0x05    /* Watchdog timeout register */
  60 #define WDCF            0x06    /* Watchdog config register */
  61 #define WDST            0x07    /* Watchdog status register */
  62
  63 /* WDCF bitfields - which devices assert WDO */
  64 #define KBC_IRQ         0x01    /* Keyboard Controller */
  65 #define MSE_IRQ         0x02    /* Mouse */
  66 #define UART1_IRQ       0x03    /* Serial0 */
  67 #define UART2_IRQ       0x04    /* Serial1 */
  68 /* 5 -7 are reserved */
  69
  70 static int timeout = 1;
  71 static int io = -1;
  72 static int io_len = 2;          /* for non plug and play */
  73 static unsigned long open_flag;
  74 static char expect_close;
  75 static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */
  76
  77 #if defined CONFIG_PNP
  78 static int isapnp = 1;
  79 static struct pnp_dev *wdt_dev;
  80
  81 module_param(isapnp, int, 0);
  82 MODULE_PARM_DESC(isapnp,
  83         "When set to 0 driver ISA PnP support will be disabled");
  84 #endif
  85
  86 module_param_hw(io, int, ioport, 0);
  87 MODULE_PARM_DESC(io, "io port");
  88 module_param(timeout, int, 0);
  89 MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
  90
  91 static bool nowayout = WATCHDOG_NOWAYOUT;
  92 module_param(nowayout, bool, 0);
  93 MODULE_PARM_DESC(nowayout,
  94         "Watchdog cannot be stopped once started (default="
  95                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  96
  97
  98
  99 /* Read from Data Register */
 100 static inline void __sc1200wdt_read_data(unsigned char index,
 101                                                 unsigned char *data)
 102 {
 103         outb_p(index, PMIR);
 104         *data = inb(PMDR);
 105 }
 106
 107 static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
 108 {
 109         spin_lock(&sc1200wdt_lock);
 110         __sc1200wdt_read_data(index, data);
 111         spin_unlock(&sc1200wdt_lock);
 112 }
 113
 114 /* Write to Data Register */
 115 static inline void __sc1200wdt_write_data(unsigned char index,
 116                                                 unsigned char data)
 117 {
 118         outb_p(index, PMIR);
 119         outb(data, PMDR);
 120 }
 121
 122 static inline void sc1200wdt_write_data(unsigned char index,
 123                                                 unsigned char data)
 124 {
 125         spin_lock(&sc1200wdt_lock);
 126         __sc1200wdt_write_data(index, data);
 127         spin_unlock(&sc1200wdt_lock);
 128 }
 129
 130
 131 static void sc1200wdt_start(void)
 132 {
 133         unsigned char reg;
 134         spin_lock(&sc1200wdt_lock);
 135
 136         __sc1200wdt_read_data(WDCF, &reg);
 137         /* assert WDO when any of the following interrupts are triggered too */
 138         reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
 139         __sc1200wdt_write_data(WDCF, reg);
 140         /* set the timeout and get the ball rolling */
 141         __sc1200wdt_write_data(WDTO, timeout);
 142
 143         spin_unlock(&sc1200wdt_lock);
 144 }
 145
 146 static void sc1200wdt_stop(void)
 147 {
 148         sc1200wdt_write_data(WDTO, 0);
 149 }
 150
 151 /* This returns the status of the WDO signal, inactive high. */
 152 static inline int sc1200wdt_status(void)
 153 {
 154         unsigned char ret;
 155
 156         sc1200wdt_read_data(WDST, &ret);
 157         /* If the bit is inactive, the watchdog is enabled, so return
 158          * KEEPALIVEPING which is a bit of a kludge because there's nothing
 159          * else for enabled/disabled status
 160          */
 161         return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
 162 }
 163
 164 static int sc1200wdt_open(struct inode *inode, struct file *file)
 165 {
 166         /* allow one at a time */
 167         if (test_and_set_bit(0, &open_flag))
 168                 return -EBUSY;
 169
 170         if (timeout > MAX_TIMEOUT)
 171                 timeout = MAX_TIMEOUT;
 172
 173         sc1200wdt_start();
 174         pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
 175
 176         return stream_open(inode, file);
 177 }
 178
 179
 180 static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
 181                                                 unsigned long arg)
 182 {
 183         int new_timeout;
 184         void __user *argp = (void __user *)arg;
 185         int __user *p = argp;
 186         static const struct watchdog_info ident = {
 187                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
 188                                                         WDIOF_MAGICCLOSE,
 189                 .firmware_version = 0,
 190                 .identity = "PC87307/PC97307",
 191         };
 192
 193         switch (cmd) {
 194         case WDIOC_GETSUPPORT:
 195                 if (copy_to_user(argp, &ident, sizeof(ident)))
 196                         return -EFAULT;
 197                 return 0;
 198
 199         case WDIOC_GETSTATUS:
 200                 return put_user(sc1200wdt_status(), p);
 201
 202         case WDIOC_GETBOOTSTATUS:
 203                 return put_user(0, p);
 204
 205         case WDIOC_SETOPTIONS:
 206         {
 207                 int options, retval = -EINVAL;
 208
 209                 if (get_user(options, p))
 210                         return -EFAULT;
 211
 212                 if (options & WDIOS_DISABLECARD) {
 213                         sc1200wdt_stop();
 214                         retval = 0;
 215                 }
 216
 217                 if (options & WDIOS_ENABLECARD) {
 218                         sc1200wdt_start();
 219                         retval = 0;
 220                 }
 221
 222                 return retval;
 223         }
 224         case WDIOC_KEEPALIVE:
 225                 sc1200wdt_write_data(WDTO, timeout);
 226                 return 0;
 227
 228         case WDIOC_SETTIMEOUT:
 229                 if (get_user(new_timeout, p))
 230                         return -EFAULT;
 231                 /* the API states this is given in secs */
 232                 new_timeout /= 60;
 233                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 234                         return -EINVAL;
 235                 timeout = new_timeout;
 236                 sc1200wdt_write_data(WDTO, timeout);
 237                 fallthrough;    /* and return the new timeout */
 238
 239         case WDIOC_GETTIMEOUT:
 240                 return put_user(timeout * 60, p);
 241
 242         default:
 243                 return -ENOTTY;
 244         }
 245 }
 246
 247
 248 static int sc1200wdt_release(struct inode *inode, struct file *file)
 249 {
 250         if (expect_close == 42) {
 251                 sc1200wdt_stop();
 252                 pr_info("Watchdog disabled\n");
 253         } else {
 254                 sc1200wdt_write_data(WDTO, timeout);
 255                 pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
 256         }
 257         clear_bit(0, &open_flag);
 258         expect_close = 0;
 259
 260         return 0;
 261 }
 262
 263
 264 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
 265                                                 size_t len, loff_t *ppos)
 266 {
 267         if (len) {
 268                 if (!nowayout) {
 269                         size_t i;
 270
 271                         expect_close = 0;
 272
 273                         for (i = 0; i != len; i++) {
 274                                 char c;
 275
 276                                 if (get_user(c, data + i))
 277                                         return -EFAULT;
 278                                 if (c == 'V')
 279                                         expect_close = 42;
 280                         }
 281                 }
 282
 283                 sc1200wdt_write_data(WDTO, timeout);
 284                 return len;
 285         }
 286
 287         return 0;
 288 }
 289
 290
 291 static int sc1200wdt_notify_sys(struct notifier_block *this,
 292                                         unsigned long code, void *unused)
 293 {
 294         if (code == SYS_DOWN || code == SYS_HALT)
 295                 sc1200wdt_stop();
 296
 297         return NOTIFY_DONE;
 298 }
 299
 300
 301 static struct notifier_block sc1200wdt_notifier = {
 302         .notifier_call =        sc1200wdt_notify_sys,
 303 };
 304
 305 static const struct file_operations sc1200wdt_fops = {
 306         .owner          = THIS_MODULE,
 307         .llseek         = no_llseek,
 308         .write          = sc1200wdt_write,
 309         .unlocked_ioctl = sc1200wdt_ioctl,
 310         .compat_ioctl   = compat_ptr_ioctl,
 311         .open           = sc1200wdt_open,
 312         .release        = sc1200wdt_release,
 313 };
 314
 315 static struct miscdevice sc1200wdt_miscdev = {
 316         .minor          = WATCHDOG_MINOR,
 317         .name           = "watchdog",
 318         .fops           = &sc1200wdt_fops,
 319 };
 320
 321
 322 static int __init sc1200wdt_probe(void)
 323 {
 324         /* The probe works by reading the PMC3 register's default value of 0x0e
 325          * there is one caveat, if the device disables the parallel port or any
 326          * of the UARTs we won't be able to detect it.
 327          * NB. This could be done with accuracy by reading the SID registers,
 328          * but we don't have access to those io regions.
 329          */
 330
 331         unsigned char reg;
 332
 333         sc1200wdt_read_data(PMC3, &reg);
 334         reg &= 0x0f;            /* we don't want the UART busy bits */
 335         return (reg == 0x0e) ? 0 : -ENODEV;
 336 }
 337
 338
 339 #if defined CONFIG_PNP
 340
 341 static const struct pnp_device_id scl200wdt_pnp_devices[] = {
 342         /* National Semiconductor PC87307/PC97307 watchdog component */
 343         {.id = "NSC0800", .driver_data = 0},
 344         {.id = ""},
 345 };
 346
 347 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
 348                                         const struct pnp_device_id *dev_id)
 349 {
 350         /* this driver only supports one card at a time */
 351         if (wdt_dev || !isapnp)
 352                 return -EBUSY;
 353
 354         wdt_dev = dev;
 355         io = pnp_port_start(wdt_dev, 0);
 356         io_len = pnp_port_len(wdt_dev, 0);
 357
 358         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 359                 pr_err("Unable to register IO port %#x\n", io);
 360                 return -EBUSY;
 361         }
 362
 363         pr_info("PnP device found at io port %#x/%d\n", io, io_len);
 364         return 0;
 365 }
 366
 367 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
 368 {
 369         if (wdt_dev) {
 370                 release_region(io, io_len);
 371                 wdt_dev = NULL;
 372         }
 373 }
 374
 375 static struct pnp_driver scl200wdt_pnp_driver = {
 376         .name           = "scl200wdt",
 377         .id_table       = scl200wdt_pnp_devices,
 378         .probe          = scl200wdt_pnp_probe,
 379         .remove         = scl200wdt_pnp_remove,
 380 };
 381
 382 #endif /* CONFIG_PNP */
 383
 384
 385 static int __init sc1200wdt_init(void)
 386 {
 387         int ret;
 388
 389         pr_info("%s\n", SC1200_MODULE_VER);
 390
 391 #if defined CONFIG_PNP
 392         if (isapnp) {
 393                 ret = pnp_register_driver(&scl200wdt_pnp_driver);
 394                 if (ret)
 395                         goto out_clean;
 396         }
 397 #endif
 398
 399         if (io == -1) {
 400                 pr_err("io parameter must be specified\n");
 401                 ret = -EINVAL;
 402                 goto out_pnp;
 403         }
 404
 405 #if defined CONFIG_PNP
 406         /* now that the user has specified an IO port and we haven't detected
 407          * any devices, disable pnp support */
 408         if (isapnp)
 409                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 410         isapnp = 0;
 411 #endif
 412
 413         if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 414                 pr_err("Unable to register IO port %#x\n", io);
 415                 ret = -EBUSY;
 416                 goto out_pnp;
 417         }
 418
 419         ret = sc1200wdt_probe();
 420         if (ret)
 421                 goto out_io;
 422
 423         ret = register_reboot_notifier(&sc1200wdt_notifier);
 424         if (ret) {
 425                 pr_err("Unable to register reboot notifier err = %d\n", ret);
 426                 goto out_io;
 427         }
 428
 429         ret = misc_register(&sc1200wdt_miscdev);
 430         if (ret) {
 431                 pr_err("Unable to register miscdev on minor %d\n",
 432                        WATCHDOG_MINOR);
 433                 goto out_rbt;
 434         }
 435
 436         /* ret = 0 */
 437
 438 out_clean:
 439         return ret;
 440
 441 out_rbt:
 442         unregister_reboot_notifier(&sc1200wdt_notifier);
 443
 444 out_io:
 445         release_region(io, io_len);
 446
 447 out_pnp:
 448 #if defined CONFIG_PNP
 449         if (isapnp)
 450                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 451 #endif
 452         goto out_clean;
 453 }
 454
 455
 456 static void __exit sc1200wdt_exit(void)
 457 {
 458         misc_deregister(&sc1200wdt_miscdev);
 459         unregister_reboot_notifier(&sc1200wdt_notifier);
 460
 461 #if defined CONFIG_PNP
 462         if (isapnp)
 463                 pnp_unregister_driver(&scl200wdt_pnp_driver);
 464         else
 465 #endif
 466         release_region(io, io_len);
 467 }
 468
 469 module_init(sc1200wdt_init);
 470 module_exit(sc1200wdt_exit);
 471
 472 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
 473 MODULE_DESCRIPTION(
 474         "Driver for National Semiconductor PC87307/PC97307 watchdog component");
 475 MODULE_LICENSE("GPL");