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 #include <asm/system.h>
  39
  40 /* #define DEBUG 1 */
  41
  42 #define DEFAULT_TIMEOUT     1           /* 1 minute */
  43 #define MAX_TIMEOUT         255
  44
  45 #define VERSION             "1.1"
  46 #define MODNAME             "pc87413 WDT"
  47 #define DPFX                MODNAME " - DEBUG: "
  48
  49 #define WDT_INDEX_IO_PORT   (io+0)      /* I/O port base (index register) */
  50 #define WDT_DATA_IO_PORT    (WDT_INDEX_IO_PORT+1)
  51 #define SWC_LDN             0x04
  52 #define SIOCFG2             0x22        /* Serial IO register */
  53 #define WDCTL               0x10        /* Watchdog-Timer-Control-Register */
  54 #define WDTO                0x11        /* Watchdog timeout register */
  55 #define WDCFG               0x12        /* Watchdog config register */
  56
  57 #define IO_DEFAULT      0x2E            /* Address used on Portwell Boards */
  58
  59 static int io = IO_DEFAULT;
  60 static int swc_base_addr = -1;
  61
  62 static int timeout = DEFAULT_TIMEOUT;   /* timeout value */
  63 static unsigned long timer_enabled;     /* is the timer enabled? */
  64
  65 static char expect_close;               /* is the close expected? */
  66
  67 static DEFINE_SPINLOCK(io_lock);        /* to guard us from io races */
  68
  69 static int nowayout = WATCHDOG_NOWAYOUT;
  70
  71 /* -- Low level function ----------------------------------------*/
  72
  73 /* Select pins for Watchdog output */
  74
  75 static inline void pc87413_select_wdt_out(void)
  76 {
  77         unsigned int cr_data = 0;
  78
  79         /* Step 1: Select multiple pin,pin55,as WDT output */
  80
  81         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  82
  83         cr_data = inb(WDT_DATA_IO_PORT);
  84
  85         cr_data |= 0x80; /* Set Bit7 to 1*/
  86         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  87
  88         outb_p(cr_data, WDT_DATA_IO_PORT);
  89
  90 #ifdef DEBUG
  91         pr_info(DPFX
  92                 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
  93                                                                 cr_data);
  94 #endif
  95 }
  96
  97 /* Enable SWC functions */
  98
  99 static inline void pc87413_enable_swc(void)
 100 {
 101         unsigned int cr_data = 0;
 102
 103         /* Step 2: Enable SWC functions */
 104
 105         outb_p(0x07, WDT_INDEX_IO_PORT);        /* Point SWC_LDN (LDN=4) */
 106         outb_p(SWC_LDN, WDT_DATA_IO_PORT);
 107
 108         outb_p(0x30, WDT_INDEX_IO_PORT);        /* Read Index 0x30 First */
 109         cr_data = inb(WDT_DATA_IO_PORT);
 110         cr_data |= 0x01;                        /* Set Bit0 to 1 */
 111         outb_p(0x30, WDT_INDEX_IO_PORT);
 112         outb_p(cr_data, WDT_DATA_IO_PORT);      /* Index0x30_bit0P1 */
 113
 114 #ifdef DEBUG
 115         pr_info(DPFX "pc87413 - Enable SWC functions\n");
 116 #endif
 117 }
 118
 119 /* Read SWC I/O base address */
 120
 121 static void pc87413_get_swc_base_addr(void)
 122 {
 123         unsigned char addr_l, addr_h = 0;
 124
 125         /* Step 3: Read SWC I/O Base Address */
 126
 127         outb_p(0x60, WDT_INDEX_IO_PORT);        /* Read Index 0x60 */
 128         addr_h = inb(WDT_DATA_IO_PORT);
 129
 130         outb_p(0x61, WDT_INDEX_IO_PORT);        /* Read Index 0x61 */
 131
 132         addr_l = inb(WDT_DATA_IO_PORT);
 133
 134         swc_base_addr = (addr_h << 8) + addr_l;
 135 #ifdef DEBUG
 136         pr_info(DPFX
 137                 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
 138                                                 addr_l, addr_h, swc_base_addr);
 139 #endif
 140 }
 141
 142 /* Select Bank 3 of SWC */
 143
 144 static inline void pc87413_swc_bank3(void)
 145 {
 146         /* Step 4: Select Bank3 of SWC */
 147         outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
 148 #ifdef DEBUG
 149         pr_info(DPFX "Select Bank3 of SWC\n");
 150 #endif
 151 }
 152
 153 /* Set watchdog timeout to x minutes */
 154
 155 static inline void pc87413_programm_wdto(char pc87413_time)
 156 {
 157         /* Step 5: Programm WDTO, Twd. */
 158         outb_p(pc87413_time, swc_base_addr + WDTO);
 159 #ifdef DEBUG
 160         pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
 161 #endif
 162 }
 163
 164 /* Enable WDEN */
 165
 166 static inline void pc87413_enable_wden(void)
 167 {
 168         /* Step 6: Enable WDEN */
 169         outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
 170 #ifdef DEBUG
 171         pr_info(DPFX "Enable WDEN\n");
 172 #endif
 173 }
 174
 175 /* Enable SW_WD_TREN */
 176 static inline void pc87413_enable_sw_wd_tren(void)
 177 {
 178         /* Enable SW_WD_TREN */
 179         outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
 180 #ifdef DEBUG
 181         pr_info(DPFX "Enable SW_WD_TREN\n");
 182 #endif
 183 }
 184
 185 /* Disable SW_WD_TREN */
 186
 187 static inline void pc87413_disable_sw_wd_tren(void)
 188 {
 189         /* Disable SW_WD_TREN */
 190         outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
 191 #ifdef DEBUG
 192         pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
 193 #endif
 194 }
 195
 196 /* Enable SW_WD_TRG */
 197
 198 static inline void pc87413_enable_sw_wd_trg(void)
 199 {
 200         /* Enable SW_WD_TRG */
 201         outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
 202 #ifdef DEBUG
 203         pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
 204 #endif
 205 }
 206
 207 /* Disable SW_WD_TRG */
 208
 209 static inline void pc87413_disable_sw_wd_trg(void)
 210 {
 211         /* Disable SW_WD_TRG */
 212         outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
 213 #ifdef DEBUG
 214         pr_info(DPFX "Disable SW_WD_TRG\n");
 215 #endif
 216 }
 217
 218 /* -- Higher level functions ------------------------------------*/
 219
 220 /* Enable the watchdog */
 221
 222 static void pc87413_enable(void)
 223 {
 224         spin_lock(&io_lock);
 225
 226         pc87413_swc_bank3();
 227         pc87413_programm_wdto(timeout);
 228         pc87413_enable_wden();
 229         pc87413_enable_sw_wd_tren();
 230         pc87413_enable_sw_wd_trg();
 231
 232         spin_unlock(&io_lock);
 233 }
 234
 235 /* Disable the watchdog */
 236
 237 static void pc87413_disable(void)
 238 {
 239         spin_lock(&io_lock);
 240
 241         pc87413_swc_bank3();
 242         pc87413_disable_sw_wd_tren();
 243         pc87413_disable_sw_wd_trg();
 244         pc87413_programm_wdto(0);
 245
 246         spin_unlock(&io_lock);
 247 }
 248
 249 /* Refresh the watchdog */
 250
 251 static void pc87413_refresh(void)
 252 {
 253         spin_lock(&io_lock);
 254
 255         pc87413_swc_bank3();
 256         pc87413_disable_sw_wd_tren();
 257         pc87413_disable_sw_wd_trg();
 258         pc87413_programm_wdto(timeout);
 259         pc87413_enable_wden();
 260         pc87413_enable_sw_wd_tren();
 261         pc87413_enable_sw_wd_trg();
 262
 263         spin_unlock(&io_lock);
 264 }
 265
 266 /* -- File operations -------------------------------------------*/
 267
 268 /**
 269  *      pc87413_open:
 270  *      @inode: inode of device
 271  *      @file: file handle to device
 272  *
 273  */
 274
 275 static int pc87413_open(struct inode *inode, struct file *file)
 276 {
 277         /* /dev/watchdog can only be opened once */
 278
 279         if (test_and_set_bit(0, &timer_enabled))
 280                 return -EBUSY;
 281
 282         if (nowayout)
 283                 __module_get(THIS_MODULE);
 284
 285         /* Reload and activate timer */
 286         pc87413_refresh();
 287
 288         pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
 289
 290         return nonseekable_open(inode, file);
 291 }
 292
 293 /**
 294  *      pc87413_release:
 295  *      @inode: inode to board
 296  *      @file: file handle to board
 297  *
 298  *      The watchdog has a configurable API. There is a religious dispute
 299  *      between people who want their watchdog to be able to shut down and
 300  *      those who want to be sure if the watchdog manager dies the machine
 301  *      reboots. In the former case we disable the counters, in the latter
 302  *      case you have to open it again very soon.
 303  */
 304
 305 static int pc87413_release(struct inode *inode, struct file *file)
 306 {
 307         /* Shut off the timer. */
 308
 309         if (expect_close == 42) {
 310                 pc87413_disable();
 311                 pr_info("Watchdog disabled, sleeping again...\n");
 312         } else {
 313                 pr_crit("Unexpected close, not stopping watchdog!\n");
 314                 pc87413_refresh();
 315         }
 316         clear_bit(0, &timer_enabled);
 317         expect_close = 0;
 318         return 0;
 319 }
 320
 321 /**
 322  *      pc87413_status:
 323  *
 324  *      return, if the watchdog is enabled (timeout is set...)
 325  */
 326
 327
 328 static int pc87413_status(void)
 329 {
 330           return 0; /* currently not supported */
 331 }
 332
 333 /**
 334  *      pc87413_write:
 335  *      @file: file handle to the watchdog
 336  *      @data: data buffer to write
 337  *      @len: length in bytes
 338  *      @ppos: pointer to the position to write. No seeks allowed
 339  *
 340  *      A write to a watchdog device is defined as a keepalive signal. Any
 341  *      write of data will do, as we we don't define content meaning.
 342  */
 343
 344 static ssize_t pc87413_write(struct file *file, const char __user *data,
 345                              size_t len, loff_t *ppos)
 346 {
 347         /* See if we got the magic character 'V' and reload the timer */
 348         if (len) {
 349                 if (!nowayout) {
 350                         size_t i;
 351
 352                         /* reset expect flag */
 353                         expect_close = 0;
 354
 355                         /* scan to see whether or not we got the
 356                            magic character */
 357                         for (i = 0; i != len; i++) {
 358                                 char c;
 359                                 if (get_user(c, data + i))
 360                                         return -EFAULT;
 361                                 if (c == 'V')
 362                                         expect_close = 42;
 363                         }
 364                 }
 365
 366                 /* someone wrote to us, we should reload the timer */
 367                 pc87413_refresh();
 368         }
 369         return len;
 370 }
 371
 372 /**
 373  *      pc87413_ioctl:
 374  *      @file: file handle to the device
 375  *      @cmd: watchdog command
 376  *      @arg: argument pointer
 377  *
 378  *      The watchdog API defines a common set of functions for all watchdogs
 379  *      according to their available features. We only actually usefully support
 380  *      querying capabilities and current status.
 381  */
 382
 383 static long pc87413_ioctl(struct file *file, unsigned int cmd,
 384                                                 unsigned long arg)
 385 {
 386         int new_timeout;
 387
 388         union {
 389                 struct watchdog_info __user *ident;
 390                 int __user *i;
 391         } uarg;
 392
 393         static const struct watchdog_info ident = {
 394                 .options          = WDIOF_KEEPALIVEPING |
 395                                     WDIOF_SETTIMEOUT |
 396                                     WDIOF_MAGICCLOSE,
 397                 .firmware_version = 1,
 398                 .identity         = "PC87413(HF/F) watchdog",
 399         };
 400
 401         uarg.i = (int __user *)arg;
 402
 403         switch (cmd) {
 404         case WDIOC_GETSUPPORT:
 405                 return copy_to_user(uarg.ident, &ident,
 406                                         sizeof(ident)) ? -EFAULT : 0;
 407         case WDIOC_GETSTATUS:
 408                 return put_user(pc87413_status(), uarg.i);
 409         case WDIOC_GETBOOTSTATUS:
 410                 return put_user(0, uarg.i);
 411         case WDIOC_SETOPTIONS:
 412         {
 413                 int options, retval = -EINVAL;
 414                 if (get_user(options, uarg.i))
 415                         return -EFAULT;
 416                 if (options & WDIOS_DISABLECARD) {
 417                         pc87413_disable();
 418                         retval = 0;
 419                 }
 420                 if (options & WDIOS_ENABLECARD) {
 421                         pc87413_enable();
 422                         retval = 0;
 423                 }
 424                 return retval;
 425         }
 426         case WDIOC_KEEPALIVE:
 427                 pc87413_refresh();
 428 #ifdef DEBUG
 429                 pr_info(DPFX "keepalive\n");
 430 #endif
 431                 return 0;
 432         case WDIOC_SETTIMEOUT:
 433                 if (get_user(new_timeout, uarg.i))
 434                         return -EFAULT;
 435                 /* the API states this is given in secs */
 436                 new_timeout /= 60;
 437                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 438                         return -EINVAL;
 439                 timeout = new_timeout;
 440                 pc87413_refresh();
 441                 /* fall through and return the new timeout... */
 442         case WDIOC_GETTIMEOUT:
 443                 new_timeout = timeout * 60;
 444                 return put_user(new_timeout, uarg.i);
 445         default:
 446                 return -ENOTTY;
 447         }
 448 }
 449
 450 /* -- Notifier funtions -----------------------------------------*/
 451
 452 /**
 453  *      notify_sys:
 454  *      @this: our notifier block
 455  *      @code: the event being reported
 456  *      @unused: unused
 457  *
 458  *      Our notifier is called on system shutdowns. We want to turn the card
 459  *      off at reboot otherwise the machine will reboot again during memory
 460  *      test or worse yet during the following fsck. This would suck, in fact
 461  *      trust me - if it happens it does suck.
 462  */
 463
 464 static int pc87413_notify_sys(struct notifier_block *this,
 465                               unsigned long code,
 466                               void *unused)
 467 {
 468         if (code == SYS_DOWN || code == SYS_HALT)
 469                 /* Turn the card off */
 470                 pc87413_disable();
 471         return NOTIFY_DONE;
 472 }
 473
 474 /* -- Module's structures ---------------------------------------*/
 475
 476 static const struct file_operations pc87413_fops = {
 477         .owner          = THIS_MODULE,
 478         .llseek         = no_llseek,
 479         .write          = pc87413_write,
 480         .unlocked_ioctl = pc87413_ioctl,
 481         .open           = pc87413_open,
 482         .release        = pc87413_release,
 483 };
 484
 485 static struct notifier_block pc87413_notifier = {
 486         .notifier_call  = pc87413_notify_sys,
 487 };
 488
 489 static struct miscdevice pc87413_miscdev = {
 490         .minor          = WATCHDOG_MINOR,
 491         .name           = "watchdog",
 492         .fops           = &pc87413_fops,
 493 };
 494
 495 /* -- Module init functions -------------------------------------*/
 496
 497 /**
 498  *      pc87413_init: module's "constructor"
 499  *
 500  *      Set up the WDT watchdog board. All we have to do is grab the
 501  *      resources we require and bitch if anyone beat us to them.
 502  *      The open() function will actually kick the board off.
 503  */
 504
 505 static int __init pc87413_init(void)
 506 {
 507         int ret;
 508
 509         pr_info("Version " VERSION " at io 0x%X\n",
 510                                                         WDT_INDEX_IO_PORT);
 511
 512         if (!request_muxed_region(io, 2, MODNAME))
 513                 return -EBUSY;
 514
 515         ret = register_reboot_notifier(&pc87413_notifier);
 516         if (ret != 0) {
 517                 pr_err("cannot register reboot notifier (err=%d)\n", ret);
 518         }
 519
 520         ret = misc_register(&pc87413_miscdev);
 521         if (ret != 0) {
 522                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 523                        WATCHDOG_MINOR, ret);
 524                 goto reboot_unreg;
 525         }
 526         pr_info("initialized. timeout=%d min\n", timeout);
 527
 528         pc87413_select_wdt_out();
 529         pc87413_enable_swc();
 530         pc87413_get_swc_base_addr();
 531
 532         if (!request_region(swc_base_addr, 0x20, MODNAME)) {
 533                 pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
 534                 ret = -EBUSY;
 535                 goto misc_unreg;
 536         }
 537
 538         pc87413_enable();
 539
 540         release_region(io, 2);
 541         return 0;
 542
 543 misc_unreg:
 544         misc_deregister(&pc87413_miscdev);
 545 reboot_unreg:
 546         unregister_reboot_notifier(&pc87413_notifier);
 547         release_region(io, 2);
 548         return ret;
 549 }
 550
 551 /**
 552  *      pc87413_exit: module's "destructor"
 553  *
 554  *      Unload the watchdog. You cannot do this with any file handles open.
 555  *      If your watchdog is set to continue ticking on close and you unload
 556  *      it, well it keeps ticking. We won't get the interrupt but the board
 557  *      will not touch PC memory so all is fine. You just have to load a new
 558  *      module in 60 seconds or reboot.
 559  */
 560
 561 static void __exit pc87413_exit(void)
 562 {
 563         /* Stop the timer before we leave */
 564         if (!nowayout) {
 565                 pc87413_disable();
 566                 pr_info("Watchdog disabled\n");
 567         }
 568
 569         misc_deregister(&pc87413_miscdev);
 570         unregister_reboot_notifier(&pc87413_notifier);
 571         release_region(swc_base_addr, 0x20);
 572
 573         pr_info("watchdog component driver removed\n");
 574 }
 575
 576 module_init(pc87413_init);
 577 module_exit(pc87413_exit);
 578
 579 MODULE_AUTHOR("Sven Anders <anders@anduras.de>, "
 580                 "Marcus Junker <junker@anduras.de>,");
 581 MODULE_DESCRIPTION("PC87413 WDT driver");
 582 MODULE_LICENSE("GPL");
 583
 584 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 585
 586 module_param(io, int, 0);
 587 MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
 588                                         __MODULE_STRING(IO_DEFAULT) ").");
 589
 590 module_param(timeout, int, 0);
 591 MODULE_PARM_DESC(timeout,
 592                 "Watchdog timeout in minutes (default="
 593                                 __MODULE_STRING(DEFAULT_TIMEOUT) ").");
 594
 595 module_param(nowayout, int, 0);
 596 MODULE_PARM_DESC(nowayout,
 597                 "Watchdog cannot be stopped once started (default="
 598                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 599