drivers/watchdog/pc87413_wdt.c

   1 /*
   2  *      NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
   3  *
   4  *      This code is based on wdt.c with original copyright.
   5  *
   6  *      (C) Copyright 2006 Sven Anders, <anders@anduras.de>
   7  *                     and Marcus Junker, <junker@anduras.de>
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  *
  14  *      Neither Sven Anders, Marcus Junker nor ANDURAS AG
  15  *      admit liability nor provide warranty for any of this software.
  16  *      This material is provided "AS-IS" and at no charge.
  17  *
  18  *      Release 1.1
  19  */
  20
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/module.h>
  24 #include <linux/types.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/watchdog.h>
  27 #include <linux/ioport.h>
  28 #include <linux/delay.h>
  29 #include <linux/notifier.h>
  30 #include <linux/fs.h>
  31 #include <linux/reboot.h>
  32 #include <linux/init.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/moduleparam.h>
  35 #include <linux/io.h>
  36 #include <linux/uaccess.h>
  37
  38
  39 /* #define DEBUG 1 */
  40
  41 #define DEFAULT_TIMEOUT     1           /* 1 minute */
  42 #define MAX_TIMEOUT         255
  43
  44 #define VERSION             "1.1"
  45 #define MODNAME             "pc87413 WDT"
  46 #define DPFX                MODNAME " - DEBUG: "
  47
  48 #define WDT_INDEX_IO_PORT   (io+0)      /* I/O port base (index register) */
  49 #define WDT_DATA_IO_PORT    (WDT_INDEX_IO_PORT+1)
  50 #define SWC_LDN             0x04
  51 #define SIOCFG2             0x22        /* Serial IO register */
  52 #define WDCTL               0x10        /* Watchdog-Timer-Control-Register */
  53 #define WDTO                0x11        /* Watchdog timeout register */
  54 #define WDCFG               0x12        /* Watchdog config register */
  55
  56 #define IO_DEFAULT      0x2E            /* Address used on Portwell Boards */
  57
  58 static int io = IO_DEFAULT;
  59 static int swc_base_addr = -1;
  60
  61 static int timeout = DEFAULT_TIMEOUT;   /* timeout value */
  62 static unsigned long timer_enabled;     /* is the timer enabled? */
  63
  64 static char expect_close;               /* is the close expected? */
  65
  66 static DEFINE_SPINLOCK(io_lock);        /* to guard us from io races */
  67
  68 static bool nowayout = WATCHDOG_NOWAYOUT;
  69
  70 /* -- Low level function ----------------------------------------*/
  71
  72 /* Select pins for Watchdog output */
  73
  74 static inline void pc87413_select_wdt_out(void)
  75 {
  76         unsigned int cr_data = 0;
  77
  78         /* Step 1: Select multiple pin,pin55,as WDT output */
  79
  80         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  81
  82         cr_data = inb(WDT_DATA_IO_PORT);
  83
  84         cr_data |= 0x80; /* Set Bit7 to 1*/
  85         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  86
  87         outb_p(cr_data, WDT_DATA_IO_PORT);
  88
  89 #ifdef DEBUG
  90         pr_info(DPFX
  91                 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
  92                                                                 cr_data);
  93 #endif
  94 }
  95
  96 /* Enable SWC functions */
  97
  98 static inline void pc87413_enable_swc(void)
  99 {
 100         unsigned int cr_data = 0;
 101
 102         /* Step 2: Enable SWC functions */
 103
 104         outb_p(0x07, WDT_INDEX_IO_PORT);        /* Point SWC_LDN (LDN=4) */
 105         outb_p(SWC_LDN, WDT_DATA_IO_PORT);
 106
 107         outb_p(0x30, WDT_INDEX_IO_PORT);        /* Read Index 0x30 First */
 108         cr_data = inb(WDT_DATA_IO_PORT);
 109         cr_data |= 0x01;                        /* Set Bit0 to 1 */
 110         outb_p(0x30, WDT_INDEX_IO_PORT);
 111         outb_p(cr_data, WDT_DATA_IO_PORT);      /* Index0x30_bit0P1 */
 112
 113 #ifdef DEBUG
 114         pr_info(DPFX "pc87413 - Enable SWC functions\n");
 115 #endif
 116 }
 117
 118 /* Read SWC I/O base address */
 119
 120 static void pc87413_get_swc_base_addr(void)
 121 {
 122         unsigned char addr_l, addr_h = 0;
 123
 124         /* Step 3: Read SWC I/O Base Address */
 125
 126         outb_p(0x60, WDT_INDEX_IO_PORT);        /* Read Index 0x60 */
 127         addr_h = inb(WDT_DATA_IO_PORT);
 128
 129         outb_p(0x61, WDT_INDEX_IO_PORT);        /* Read Index 0x61 */
 130
 131         addr_l = inb(WDT_DATA_IO_PORT);
 132
 133         swc_base_addr = (addr_h << 8) + addr_l;
 134 #ifdef DEBUG
 135         pr_info(DPFX
 136                 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
 137                                                 addr_l, addr_h, swc_base_addr);
 138 #endif
 139 }
 140
 141 /* Select Bank 3 of SWC */
 142
 143 static inline void pc87413_swc_bank3(void)
 144 {
 145         /* Step 4: Select Bank3 of SWC */
 146         outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
 147 #ifdef DEBUG
 148         pr_info(DPFX "Select Bank3 of SWC\n");
 149 #endif
 150 }
 151
 152 /* Set watchdog timeout to x minutes */
 153
 154 static inline void pc87413_programm_wdto(char pc87413_time)
 155 {
 156         /* Step 5: Programm WDTO, Twd. */
 157         outb_p(pc87413_time, swc_base_addr + WDTO);
 158 #ifdef DEBUG
 159         pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
 160 #endif
 161 }
 162
 163 /* Enable WDEN */
 164
 165 static inline void pc87413_enable_wden(void)
 166 {
 167         /* Step 6: Enable WDEN */
 168         outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
 169 #ifdef DEBUG
 170         pr_info(DPFX "Enable WDEN\n");
 171 #endif
 172 }
 173
 174 /* Enable SW_WD_TREN */
 175 static inline void pc87413_enable_sw_wd_tren(void)
 176 {
 177         /* Enable SW_WD_TREN */
 178         outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
 179 #ifdef DEBUG
 180         pr_info(DPFX "Enable SW_WD_TREN\n");
 181 #endif
 182 }
 183
 184 /* Disable SW_WD_TREN */
 185
 186 static inline void pc87413_disable_sw_wd_tren(void)
 187 {
 188         /* Disable SW_WD_TREN */
 189         outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
 190 #ifdef DEBUG
 191         pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
 192 #endif
 193 }
 194
 195 /* Enable SW_WD_TRG */
 196
 197 static inline void pc87413_enable_sw_wd_trg(void)
 198 {
 199         /* Enable SW_WD_TRG */
 200         outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
 201 #ifdef DEBUG
 202         pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
 203 #endif
 204 }
 205
 206 /* Disable SW_WD_TRG */
 207
 208 static inline void pc87413_disable_sw_wd_trg(void)
 209 {
 210         /* Disable SW_WD_TRG */
 211         outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
 212 #ifdef DEBUG
 213         pr_info(DPFX "Disable SW_WD_TRG\n");
 214 #endif
 215 }
 216
 217 /* -- Higher level functions ------------------------------------*/
 218
 219 /* Enable the watchdog */
 220
 221 static void pc87413_enable(void)
 222 {
 223         spin_lock(&io_lock);
 224
 225         pc87413_swc_bank3();
 226         pc87413_programm_wdto(timeout);
 227         pc87413_enable_wden();
 228         pc87413_enable_sw_wd_tren();
 229         pc87413_enable_sw_wd_trg();
 230
 231         spin_unlock(&io_lock);
 232 }
 233
 234 /* Disable the watchdog */
 235
 236 static void pc87413_disable(void)
 237 {
 238         spin_lock(&io_lock);
 239
 240         pc87413_swc_bank3();
 241         pc87413_disable_sw_wd_tren();
 242         pc87413_disable_sw_wd_trg();
 243         pc87413_programm_wdto(0);
 244
 245         spin_unlock(&io_lock);
 246 }
 247
 248 /* Refresh the watchdog */
 249
 250 static void pc87413_refresh(void)
 251 {
 252         spin_lock(&io_lock);
 253
 254         pc87413_swc_bank3();
 255         pc87413_disable_sw_wd_tren();
 256         pc87413_disable_sw_wd_trg();
 257         pc87413_programm_wdto(timeout);
 258         pc87413_enable_wden();
 259         pc87413_enable_sw_wd_tren();
 260         pc87413_enable_sw_wd_trg();
 261
 262         spin_unlock(&io_lock);
 263 }
 264
 265 /* -- File operations -------------------------------------------*/
 266
 267 /**
 268  *      pc87413_open:
 269  *      @inode: inode of device
 270  *      @file: file handle to device
 271  *
 272  */
 273
 274 static int pc87413_open(struct inode *inode, struct file *file)
 275 {
 276         /* /dev/watchdog can only be opened once */
 277
 278         if (test_and_set_bit(0, &timer_enabled))
 279                 return -EBUSY;
 280
 281         if (nowayout)
 282                 __module_get(THIS_MODULE);
 283
 284         /* Reload and activate timer */
 285         pc87413_refresh();
 286
 287         pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
 288
 289         return nonseekable_open(inode, file);
 290 }
 291
 292 /**
 293  *      pc87413_release:
 294  *      @inode: inode to board
 295  *      @file: file handle to board
 296  *
 297  *      The watchdog has a configurable API. There is a religious dispute
 298  *      between people who want their watchdog to be able to shut down and
 299  *      those who want to be sure if the watchdog manager dies the machine
 300  *      reboots. In the former case we disable the counters, in the latter
 301  *      case you have to open it again very soon.
 302  */
 303
 304 static int pc87413_release(struct inode *inode, struct file *file)
 305 {
 306         /* Shut off the timer. */
 307
 308         if (expect_close == 42) {
 309                 pc87413_disable();
 310                 pr_info("Watchdog disabled, sleeping again...\n");
 311         } else {
 312                 pr_crit("Unexpected close, not stopping watchdog!\n");
 313                 pc87413_refresh();
 314         }
 315         clear_bit(0, &timer_enabled);
 316         expect_close = 0;
 317         return 0;
 318 }
 319
 320 /**
 321  *      pc87413_status:
 322  *
 323  *      return, if the watchdog is enabled (timeout is set...)
 324  */
 325
 326
 327 static int pc87413_status(void)
 328 {
 329           return 0; /* currently not supported */
 330 }
 331
 332 /**
 333  *      pc87413_write:
 334  *      @file: file handle to the watchdog
 335  *      @data: data buffer to write
 336  *      @len: length in bytes
 337  *      @ppos: pointer to the position to write. No seeks allowed
 338  *
 339  *      A write to a watchdog device is defined as a keepalive signal. Any
 340  *      write of data will do, as we we don't define content meaning.
 341  */
 342
 343 static ssize_t pc87413_write(struct file *file, const char __user *data,
 344                              size_t len, loff_t *ppos)
 345 {
 346         /* See if we got the magic character 'V' and reload the timer */
 347         if (len) {
 348                 if (!nowayout) {
 349                         size_t i;
 350
 351                         /* reset expect flag */
 352                         expect_close = 0;
 353
 354                         /* scan to see whether or not we got the
 355                            magic character */
 356                         for (i = 0; i != len; i++) {
 357                                 char c;
 358                                 if (get_user(c, data + i))
 359                                         return -EFAULT;
 360                                 if (c == 'V')
 361                                         expect_close = 42;
 362                         }
 363                 }
 364
 365                 /* someone wrote to us, we should reload the timer */
 366                 pc87413_refresh();
 367         }
 368         return len;
 369 }
 370
 371 /**
 372  *      pc87413_ioctl:
 373  *      @file: file handle to the device
 374  *      @cmd: watchdog command
 375  *      @arg: argument pointer
 376  *
 377  *      The watchdog API defines a common set of functions for all watchdogs
 378  *      according to their available features. We only actually usefully support
 379  *      querying capabilities and current status.
 380  */
 381
 382 static long pc87413_ioctl(struct file *file, unsigned int cmd,
 383                                                 unsigned long arg)
 384 {
 385         int new_timeout;
 386
 387         union {
 388                 struct watchdog_info __user *ident;
 389                 int __user *i;
 390         } uarg;
 391
 392         static const struct watchdog_info ident = {
 393                 .options          = WDIOF_KEEPALIVEPING |
 394                                     WDIOF_SETTIMEOUT |
 395                                     WDIOF_MAGICCLOSE,
 396                 .firmware_version = 1,
 397                 .identity         = "PC87413(HF/F) watchdog",
 398         };
 399
 400         uarg.i = (int __user *)arg;
 401
 402         switch (cmd) {
 403         case WDIOC_GETSUPPORT:
 404                 return copy_to_user(uarg.ident, &ident,
 405                                         sizeof(ident)) ? -EFAULT : 0;
 406         case WDIOC_GETSTATUS:
 407                 return put_user(pc87413_status(), uarg.i);
 408         case WDIOC_GETBOOTSTATUS:
 409                 return put_user(0, uarg.i);
 410         case WDIOC_SETOPTIONS:
 411         {
 412                 int options, retval = -EINVAL;
 413                 if (get_user(options, uarg.i))
 414                         return -EFAULT;
 415                 if (options & WDIOS_DISABLECARD) {
 416                         pc87413_disable();
 417                         retval = 0;
 418                 }
 419                 if (options & WDIOS_ENABLECARD) {
 420                         pc87413_enable();
 421                         retval = 0;
 422                 }
 423                 return retval;
 424         }
 425         case WDIOC_KEEPALIVE:
 426                 pc87413_refresh();
 427 #ifdef DEBUG
 428                 pr_info(DPFX "keepalive\n");
 429 #endif
 430                 return 0;
 431         case WDIOC_SETTIMEOUT:
 432                 if (get_user(new_timeout, uarg.i))
 433                         return -EFAULT;
 434                 /* the API states this is given in secs */
 435                 new_timeout /= 60;
 436                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 437                         return -EINVAL;
 438                 timeout = new_timeout;
 439                 pc87413_refresh();
 440                 /* fall through and return the new timeout... */
 441         case WDIOC_GETTIMEOUT:
 442                 new_timeout = timeout * 60;
 443                 return put_user(new_timeout, uarg.i);
 444         default:
 445                 return -ENOTTY;
 446         }
 447 }
 448
 449 /* -- Notifier funtions -----------------------------------------*/
 450
 451 /**
 452  *      notify_sys:
 453  *      @this: our notifier block
 454  *      @code: the event being reported
 455  *      @unused: unused
 456  *
 457  *      Our notifier is called on system shutdowns. We want to turn the card
 458  *      off at reboot otherwise the machine will reboot again during memory
 459  *      test or worse yet during the following fsck. This would suck, in fact
 460  *      trust me - if it happens it does suck.
 461  */
 462
 463 static int pc87413_notify_sys(struct notifier_block *this,
 464                               unsigned long code,
 465                               void *unused)
 466 {
 467         if (code == SYS_DOWN || code == SYS_HALT)
 468                 /* Turn the card off */
 469                 pc87413_disable();
 470         return NOTIFY_DONE;
 471 }
 472
 473 /* -- Module's structures ---------------------------------------*/
 474
 475 static const struct file_operations pc87413_fops = {
 476         .owner          = THIS_MODULE,
 477         .llseek         = no_llseek,
 478         .write          = pc87413_write,
 479         .unlocked_ioctl = pc87413_ioctl,
 480         .open           = pc87413_open,
 481         .release        = pc87413_release,
 482 };
 483
 484 static struct notifier_block pc87413_notifier = {
 485         .notifier_call  = pc87413_notify_sys,
 486 };
 487
 488 static struct miscdevice pc87413_miscdev = {
 489         .minor          = WATCHDOG_MINOR,
 490         .name           = "watchdog",
 491         .fops           = &pc87413_fops,
 492 };
 493
 494 /* -- Module init functions -------------------------------------*/
 495
 496 /**
 497  *      pc87413_init: module's "constructor"
 498  *
 499  *      Set up the WDT watchdog board. All we have to do is grab the
 500  *      resources we require and bitch if anyone beat us to them.
 501  *      The open() function will actually kick the board off.
 502  */
 503
 504 static int __init pc87413_init(void)
 505 {
 506         int ret;
 507
 508         pr_info("Version " VERSION " at io 0x%X\n",
 509                                                         WDT_INDEX_IO_PORT);
 510
 511         if (!request_muxed_region(io, 2, MODNAME))
 512                 return -EBUSY;
 513
 514         ret = register_reboot_notifier(&pc87413_notifier);
 515         if (ret != 0) {
 516                 pr_err("cannot register reboot notifier (err=%d)\n", ret);
 517         }
 518
 519         ret = misc_register(&pc87413_miscdev);
 520         if (ret != 0) {
 521                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 522                        WATCHDOG_MINOR, ret);
 523                 goto reboot_unreg;
 524         }
 525         pr_info("initialized. timeout=%d min\n", timeout);
 526
 527         pc87413_select_wdt_out();
 528         pc87413_enable_swc();
 529         pc87413_get_swc_base_addr();
 530
 531         if (!request_region(swc_base_addr, 0x20, MODNAME)) {
 532                 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
 533                 ret = -EBUSY;
 534                 goto misc_unreg;
 535         }
 536
 537         pc87413_enable();
 538
 539         release_region(io, 2);
 540         return 0;
 541
 542 misc_unreg:
 543         misc_deregister(&pc87413_miscdev);
 544 reboot_unreg:
 545         unregister_reboot_notifier(&pc87413_notifier);
 546         release_region(io, 2);
 547         return ret;
 548 }
 549
 550 /**
 551  *      pc87413_exit: module's "destructor"
 552  *
 553  *      Unload the watchdog. You cannot do this with any file handles open.
 554  *      If your watchdog is set to continue ticking on close and you unload
 555  *      it, well it keeps ticking. We won't get the interrupt but the board
 556  *      will not touch PC memory so all is fine. You just have to load a new
 557  *      module in 60 seconds or reboot.
 558  */
 559
 560 static void __exit pc87413_exit(void)
 561 {
 562         /* Stop the timer before we leave */
 563         if (!nowayout) {
 564                 pc87413_disable();
 565                 pr_info("Watchdog disabled\n");
 566         }
 567
 568         misc_deregister(&pc87413_miscdev);
 569         unregister_reboot_notifier(&pc87413_notifier);
 570         release_region(swc_base_addr, 0x20);
 571
 572         pr_info("watchdog component driver removed\n");
 573 }
 574
 575 module_init(pc87413_init);
 576 module_exit(pc87413_exit);
 577
 578 MODULE_AUTHOR("Sven Anders <anders@anduras.de>, "
 579                 "Marcus Junker <junker@anduras.de>,");
 580 MODULE_DESCRIPTION("PC87413 WDT driver");
 581 MODULE_LICENSE("GPL");
 582
 583 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 584
 585 module_param(io, int, 0);
 586 MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
 587                                         __MODULE_STRING(IO_DEFAULT) ").");
 588
 589 module_param(timeout, int, 0);
 590 MODULE_PARM_DESC(timeout,
 591                 "Watchdog timeout in minutes (default="
 592                                 __MODULE_STRING(DEFAULT_TIMEOUT) ").");
 593
 594 module_param(nowayout, bool, 0);
 595 MODULE_PARM_DESC(nowayout,
 596                 "Watchdog cannot be stopped once started (default="
 597                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 598