drivers/watchdog/eurotechwdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *      Eurotech CPU-1220/1410/1420 on board WDT driver
   4  *
   5  *      (c) Copyright 2001 Ascensit <support@ascensit.com>
   6  *      (c) Copyright 2001 Rodolfo Giometti <giometti@ascensit.com>
   7  *      (c) Copyright 2002 Rob Radez <rob@osinvestor.com>
   8  *
   9  *      Based on wdt.c.
  10  *      Original copyright messages:
  11  *
  12  *      (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  13  *                                              All Rights Reserved.
  14  *
  15  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  16  *      warranty for any of this software. This material is provided
  17  *      "AS-IS" and at no charge.
  18  *
  19  *      (c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>*
  20  */
  21
  22 /* Changelog:
  23  *
  24  * 2001 - Rodolfo Giometti
  25  *      Initial release
  26  *
  27  * 2002/04/25 - Rob Radez
  28  *      clean up #includes
  29  *      clean up locking
  30  *      make __setup param unique
  31  *      proper options in watchdog_info
  32  *      add WDIOC_GETSTATUS and WDIOC_SETOPTIONS ioctls
  33  *      add expect_close support
  34  *
  35  * 2002.05.30 - Joel Becker <joel.becker@oracle.com>
  36  *      Added Matt Domsch's nowayout module option.
  37  */
  38
  39 /*
  40  *      The eurotech CPU-1220/1410/1420's watchdog is a part
  41  *      of the on-board SUPER I/O device SMSC FDC 37B782.
  42  */
  43
  44 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  45
  46 #include <linux/interrupt.h>
  47 #include <linux/module.h>
  48 #include <linux/moduleparam.h>
  49 #include <linux/types.h>
  50 #include <linux/miscdevice.h>
  51 #include <linux/watchdog.h>
  52 #include <linux/fs.h>
  53 #include <linux/ioport.h>
  54 #include <linux/notifier.h>
  55 #include <linux/reboot.h>
  56 #include <linux/init.h>
  57 #include <linux/io.h>
  58 #include <linux/uaccess.h>
  59
  60
  61 static unsigned long eurwdt_is_open;
  62 static int eurwdt_timeout;
  63 static char eur_expect_close;
  64 static DEFINE_SPINLOCK(eurwdt_lock);
  65
  66 /*
  67  * You must set these - there is no sane way to probe for this board.
  68  */
  69
  70 static int io = 0x3f0;
  71 static int irq = 10;
  72 static char *ev = "int";
  73
  74 #define WDT_TIMEOUT             60                /* 1 minute */
  75
  76 static bool nowayout = WATCHDOG_NOWAYOUT;
  77 module_param(nowayout, bool, 0);
  78 MODULE_PARM_DESC(nowayout,
  79                 "Watchdog cannot be stopped once started (default="
  80                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  81
  82 /*
  83  * Some symbolic names
  84  */
  85
  86 #define WDT_CTRL_REG            0x30
  87 #define WDT_OUTPIN_CFG          0xe2
  88 #define WDT_EVENT_INT           0x00
  89 #define WDT_EVENT_REBOOT        0x08
  90 #define WDT_UNIT_SEL            0xf1
  91 #define WDT_UNIT_SECS           0x80
  92 #define WDT_TIMEOUT_VAL         0xf2
  93 #define WDT_TIMER_CFG           0xf3
  94
  95
  96 module_param_hw(io, int, ioport, 0);
  97 MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
  98 module_param_hw(irq, int, irq, 0);
  99 MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
 100 module_param(ev, charp, 0);
 101 MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
 102
 103
 104 /*
 105  * Programming support
 106  */
 107
 108 static inline void eurwdt_write_reg(u8 index, u8 data)
 109 {
 110         outb(index, io);
 111         outb(data, io+1);
 112 }
 113
 114 static inline void eurwdt_lock_chip(void)
 115 {
 116         outb(0xaa, io);
 117 }
 118
 119 static inline void eurwdt_unlock_chip(void)
 120 {
 121         outb(0x55, io);
 122         eurwdt_write_reg(0x07, 0x08);   /* set the logical device */
 123 }
 124
 125 static inline void eurwdt_set_timeout(int timeout)
 126 {
 127         eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout);
 128 }
 129
 130 static inline void eurwdt_disable_timer(void)
 131 {
 132         eurwdt_set_timeout(0);
 133 }
 134
 135 static void eurwdt_activate_timer(void)
 136 {
 137         eurwdt_disable_timer();
 138         eurwdt_write_reg(WDT_CTRL_REG, 0x01);   /* activate the WDT */
 139         eurwdt_write_reg(WDT_OUTPIN_CFG,
 140                 !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT);
 141
 142         /* Setting interrupt line */
 143         if (irq == 2 || irq > 15 || irq < 0) {
 144                 pr_err("invalid irq number\n");
 145                 irq = 0;        /* if invalid we disable interrupt */
 146         }
 147         if (irq == 0)
 148                 pr_info("interrupt disabled\n");
 149
 150         eurwdt_write_reg(WDT_TIMER_CFG, irq << 4);
 151
 152         eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS);  /* we use seconds */
 153         eurwdt_set_timeout(0);  /* the default timeout */
 154 }
 155
 156
 157 /*
 158  * Kernel methods.
 159  */
 160
 161 static irqreturn_t eurwdt_interrupt(int irq, void *dev_id)
 162 {
 163         pr_crit("timeout WDT timeout\n");
 164
 165 #ifdef ONLY_TESTING
 166         pr_crit("Would Reboot\n");
 167 #else
 168         pr_crit("Initiating system reboot\n");
 169         emergency_restart();
 170 #endif
 171         return IRQ_HANDLED;
 172 }
 173
 174
 175 /**
 176  * eurwdt_ping:
 177  *
 178  * Reload counter one with the watchdog timeout.
 179  */
 180
 181 static void eurwdt_ping(void)
 182 {
 183         /* Write the watchdog default value */
 184         eurwdt_set_timeout(eurwdt_timeout);
 185 }
 186
 187 /**
 188  * eurwdt_write:
 189  * @file: file handle to the watchdog
 190  * @buf: buffer to write (unused as data does not matter here
 191  * @count: count of bytes
 192  * @ppos: pointer to the position to write. No seeks allowed
 193  *
 194  * A write to a watchdog device is defined as a keepalive signal. Any
 195  * write of data will do, as we we don't define content meaning.
 196  */
 197
 198 static ssize_t eurwdt_write(struct file *file, const char __user *buf,
 199 size_t count, loff_t *ppos)
 200 {
 201         if (count) {
 202                 if (!nowayout) {
 203                         size_t i;
 204
 205                         eur_expect_close = 0;
 206
 207                         for (i = 0; i != count; i++) {
 208                                 char c;
 209                                 if (get_user(c, buf + i))
 210                                         return -EFAULT;
 211                                 if (c == 'V')
 212                                         eur_expect_close = 42;
 213                         }
 214                 }
 215                 spin_lock(&eurwdt_lock);
 216                 eurwdt_ping();  /* the default timeout */
 217                 spin_unlock(&eurwdt_lock);
 218         }
 219         return count;
 220 }
 221
 222 /**
 223  * eurwdt_ioctl:
 224  * @file: file handle to the device
 225  * @cmd: watchdog command
 226  * @arg: argument pointer
 227  *
 228  * The watchdog API defines a common set of functions for all watchdogs
 229  * according to their available features.
 230  */
 231
 232 static long eurwdt_ioctl(struct file *file,
 233                                         unsigned int cmd, unsigned long arg)
 234 {
 235         void __user *argp = (void __user *)arg;
 236         int __user *p = argp;
 237         static const struct watchdog_info ident = {
 238                 .options          = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
 239                                                         | WDIOF_MAGICCLOSE,
 240                 .firmware_version = 1,
 241                 .identity         = "WDT Eurotech CPU-1220/1410",
 242         };
 243
 244         int time;
 245         int options, retval = -EINVAL;
 246
 247         switch (cmd) {
 248         case WDIOC_GETSUPPORT:
 249                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 250
 251         case WDIOC_GETSTATUS:
 252         case WDIOC_GETBOOTSTATUS:
 253                 return put_user(0, p);
 254
 255         case WDIOC_SETOPTIONS:
 256                 if (get_user(options, p))
 257                         return -EFAULT;
 258                 spin_lock(&eurwdt_lock);
 259                 if (options & WDIOS_DISABLECARD) {
 260                         eurwdt_disable_timer();
 261                         retval = 0;
 262                 }
 263                 if (options & WDIOS_ENABLECARD) {
 264                         eurwdt_activate_timer();
 265                         eurwdt_ping();
 266                         retval = 0;
 267                 }
 268                 spin_unlock(&eurwdt_lock);
 269                 return retval;
 270
 271         case WDIOC_KEEPALIVE:
 272                 spin_lock(&eurwdt_lock);
 273                 eurwdt_ping();
 274                 spin_unlock(&eurwdt_lock);
 275                 return 0;
 276
 277         case WDIOC_SETTIMEOUT:
 278                 if (copy_from_user(&time, p, sizeof(int)))
 279                         return -EFAULT;
 280
 281                 /* Sanity check */
 282                 if (time < 0 || time > 255)
 283                         return -EINVAL;
 284
 285                 spin_lock(&eurwdt_lock);
 286                 eurwdt_timeout = time;
 287                 eurwdt_set_timeout(time);
 288                 spin_unlock(&eurwdt_lock);
 289                 fallthrough;
 290
 291         case WDIOC_GETTIMEOUT:
 292                 return put_user(eurwdt_timeout, p);
 293
 294         default:
 295                 return -ENOTTY;
 296         }
 297 }
 298
 299 /**
 300  * eurwdt_open:
 301  * @inode: inode of device
 302  * @file: file handle to device
 303  *
 304  * The misc device has been opened. The watchdog device is single
 305  * open and on opening we load the counter.
 306  */
 307
 308 static int eurwdt_open(struct inode *inode, struct file *file)
 309 {
 310         if (test_and_set_bit(0, &eurwdt_is_open))
 311                 return -EBUSY;
 312         eurwdt_timeout = WDT_TIMEOUT;   /* initial timeout */
 313         /* Activate the WDT */
 314         eurwdt_activate_timer();
 315         return stream_open(inode, file);
 316 }
 317
 318 /**
 319  * eurwdt_release:
 320  * @inode: inode to board
 321  * @file: file handle to board
 322  *
 323  * The watchdog has a configurable API. There is a religious dispute
 324  * between people who want their watchdog to be able to shut down and
 325  * those who want to be sure if the watchdog manager dies the machine
 326  * reboots. In the former case we disable the counters, in the latter
 327  * case you have to open it again very soon.
 328  */
 329
 330 static int eurwdt_release(struct inode *inode, struct file *file)
 331 {
 332         if (eur_expect_close == 42)
 333                 eurwdt_disable_timer();
 334         else {
 335                 pr_crit("Unexpected close, not stopping watchdog!\n");
 336                 eurwdt_ping();
 337         }
 338         clear_bit(0, &eurwdt_is_open);
 339         eur_expect_close = 0;
 340         return 0;
 341 }
 342
 343 /**
 344  * eurwdt_notify_sys:
 345  * @this: our notifier block
 346  * @code: the event being reported
 347  * @unused: unused
 348  *
 349  * Our notifier is called on system shutdowns. We want to turn the card
 350  * off at reboot otherwise the machine will reboot again during memory
 351  * test or worse yet during the following fsck. This would suck, in fact
 352  * trust me - if it happens it does suck.
 353  */
 354
 355 static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code,
 356         void *unused)
 357 {
 358         if (code == SYS_DOWN || code == SYS_HALT)
 359                 eurwdt_disable_timer(); /* Turn the card off */
 360
 361         return NOTIFY_DONE;
 362 }
 363
 364 /*
 365  * Kernel Interfaces
 366  */
 367
 368
 369 static const struct file_operations eurwdt_fops = {
 370         .owner          = THIS_MODULE,
 371         .llseek         = no_llseek,
 372         .write          = eurwdt_write,
 373         .unlocked_ioctl = eurwdt_ioctl,
 374         .compat_ioctl   = compat_ptr_ioctl,
 375         .open           = eurwdt_open,
 376         .release        = eurwdt_release,
 377 };
 378
 379 static struct miscdevice eurwdt_miscdev = {
 380         .minor  = WATCHDOG_MINOR,
 381         .name   = "watchdog",
 382         .fops   = &eurwdt_fops,
 383 };
 384
 385 /*
 386  * The WDT card needs to learn about soft shutdowns in order to
 387  * turn the timebomb registers off.
 388  */
 389
 390 static struct notifier_block eurwdt_notifier = {
 391         .notifier_call = eurwdt_notify_sys,
 392 };
 393
 394 /**
 395  * cleanup_module:
 396  *
 397  * Unload the watchdog. You cannot do this with any file handles open.
 398  * If your watchdog is set to continue ticking on close and you unload
 399  * it, well it keeps ticking. We won't get the interrupt but the board
 400  * will not touch PC memory so all is fine. You just have to load a new
 401  * module in 60 seconds or reboot.
 402  */
 403
 404 static void __exit eurwdt_exit(void)
 405 {
 406         eurwdt_lock_chip();
 407
 408         misc_deregister(&eurwdt_miscdev);
 409
 410         unregister_reboot_notifier(&eurwdt_notifier);
 411         release_region(io, 2);
 412         free_irq(irq, NULL);
 413 }
 414
 415 /**
 416  * eurwdt_init:
 417  *
 418  * Set up the WDT watchdog board. After grabbing the resources
 419  * we require we need also to unlock the device.
 420  * The open() function will actually kick the board off.
 421  */
 422
 423 static int __init eurwdt_init(void)
 424 {
 425         int ret;
 426
 427         ret = request_irq(irq, eurwdt_interrupt, 0, "eurwdt", NULL);
 428         if (ret) {
 429                 pr_err("IRQ %d is not free\n", irq);
 430                 goto out;
 431         }
 432
 433         if (!request_region(io, 2, "eurwdt")) {
 434                 pr_err("IO %X is not free\n", io);
 435                 ret = -EBUSY;
 436                 goto outirq;
 437         }
 438
 439         ret = register_reboot_notifier(&eurwdt_notifier);
 440         if (ret) {
 441                 pr_err("can't register reboot notifier (err=%d)\n", ret);
 442                 goto outreg;
 443         }
 444
 445         ret = misc_register(&eurwdt_miscdev);
 446         if (ret) {
 447                 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
 448                 goto outreboot;
 449         }
 450
 451         eurwdt_unlock_chip();
 452
 453         ret = 0;
 454         pr_info("Eurotech WDT driver 0.01 at %X (Interrupt %d) - timeout event: %s\n",
 455                 io, irq, (!strcmp("int", ev) ? "int" : "reboot"));
 456
 457 out:
 458         return ret;
 459
 460 outreboot:
 461         unregister_reboot_notifier(&eurwdt_notifier);
 462
 463 outreg:
 464         release_region(io, 2);
 465
 466 outirq:
 467         free_irq(irq, NULL);
 468         goto out;
 469 }
 470
 471 module_init(eurwdt_init);
 472 module_exit(eurwdt_exit);
 473
 474 MODULE_AUTHOR("Rodolfo Giometti");
 475 MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog");
 476 MODULE_LICENSE("GPL");