drivers/char/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 #include <linux/config.h>
  22 #include <linux/module.h>
  23 #include <linux/types.h>
  24 #include <linux/miscdevice.h>
  25 #include <linux/watchdog.h>
  26 #include <linux/ioport.h>
  27 #include <linux/delay.h>
  28 #include <linux/notifier.h>
  29 #include <linux/fs.h>
  30 #include <linux/reboot.h>
  31 #include <linux/init.h>
  32 #include <linux/spinlock.h>
  33 #include <linux/moduleparam.h>
  34 #include <linux/version.h>
  35
  36 #include <asm/io.h>
  37 #include <asm/uaccess.h>
  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 PFX                 MODNAME ": "
  48 #define DPFX                MODNAME " - DEBUG: "
  49
  50 #define WDT_INDEX_IO_PORT   (io+0)       /* I/O port base (index register) */
  51 #define WDT_DATA_IO_PORT    (WDT_INDEX_IO_PORT+1)
  52 #define SWC_LDN             0x04
  53 #define SIOCFG2             0x22         /* Serial IO register */
  54 #define WDCTL               0x10         /* Watchdog-Timer-Controll-Register */
  55 #define WDTO                0x11         /* Watchdog timeout register */
  56 #define WDCFG               0x12         /* Watchdog config register */
  57
  58 static int io = 0x2E;                    /* Address used on Portwell Boards */
  59
  60 static int timeout = DEFAULT_TIMEOUT;    /* timeout value */
  61 static unsigned long timer_enabled = 0;  /* is the timer enabled? */
  62
  63 static char expect_close;                /* is the close expected? */
  64
  65 static spinlock_t io_lock;               /* to guard the watchdog from io races */
  66
  67 static int nowayout = WATCHDOG_NOWAYOUT;
  68
  69 /* -- Low level function ----------------------------------------*/
  70
  71 /* Select pins for Watchdog output */
  72
  73 static inline void pc87413_select_wdt_out (void)
  74 {
  75         unsigned int cr_data = 0;
  76
  77         /* Step 1: Select multiple pin,pin55,as WDT output */
  78
  79         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  80
  81         cr_data = inb (WDT_DATA_IO_PORT);
  82
  83         cr_data |= 0x80; /* Set Bit7 to 1*/
  84         outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  85
  86         outb_p(cr_data, WDT_DATA_IO_PORT);
  87
  88 #ifdef DEBUG
  89         printk(KERN_INFO DPFX "Select multiple pin,pin55,as WDT output:"
  90                               " Bit7 to 1: %d\n", cr_data);
  91 #endif
  92 }
  93
  94 /* Enable SWC functions */
  95
  96 static inline void pc87413_enable_swc(void)
  97 {
  98         unsigned int cr_data=0;
  99
 100         /* Step 2: Enable SWC functions */
 101
 102         outb_p(0x07, WDT_INDEX_IO_PORT);        /* Point SWC_LDN (LDN=4) */
 103         outb_p(SWC_LDN, WDT_DATA_IO_PORT);
 104
 105         outb_p(0x30, WDT_INDEX_IO_PORT);        /* Read Index 0x30 First */
 106         cr_data = inb(WDT_DATA_IO_PORT);
 107         cr_data |= 0x01;                        /* Set Bit0 to 1 */
 108         outb_p(0x30, WDT_INDEX_IO_PORT);
 109         outb_p(cr_data, WDT_DATA_IO_PORT);      /* Index0x30_bit0P1 */
 110
 111 #ifdef DEBUG
 112         printk(KERN_INFO DPFX "pc87413 - Enable SWC functions\n");
 113 #endif
 114 }
 115
 116 /* Read SWC I/O base address */
 117
 118 static inline unsigned int pc87413_get_swc_base(void)
 119 {
 120         unsigned int  swc_base_addr = 0;
 121         unsigned char addr_l, addr_h = 0;
 122
 123         /* Step 3: Read SWC I/O Base Address */
 124
 125         outb_p(0x60, WDT_INDEX_IO_PORT);        /* Read Index 0x60 */
 126         addr_h = inb(WDT_DATA_IO_PORT);
 127
 128         outb_p(0x61, WDT_INDEX_IO_PORT);        /* Read Index 0x61 */
 129
 130         addr_l = inb(WDT_DATA_IO_PORT);
 131
 132         swc_base_addr = (addr_h << 8) + addr_l;
 133
 134 #ifdef DEBUG
 135         printk(KERN_INFO DPFX "Read SWC I/O Base Address: low %d, high %d,"
 136                               " res %d\n", addr_l, addr_h, swc_base_addr);
 137 #endif
 138
 139         return swc_base_addr;
 140 }
 141
 142 /* Select Bank 3 of SWC */
 143
 144 static inline void pc87413_swc_bank3(unsigned int swc_base_addr)
 145 {
 146         /* Step 4: Select Bank3 of SWC */
 147
 148         outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
 149
 150 #ifdef DEBUG
 151         printk(KERN_INFO DPFX "Select Bank3 of SWC\n");
 152 #endif
 153 }
 154
 155 /* Set watchdog timeout to x minutes */
 156
 157 static inline void pc87413_programm_wdto(unsigned int swc_base_addr,
 158                                          char pc87413_time)
 159 {
 160         /* Step 5: Programm WDTO, Twd. */
 161
 162         outb_p(pc87413_time, swc_base_addr + WDTO);
 163
 164 #ifdef DEBUG
 165         printk(KERN_INFO DPFX "Set WDTO to %d minutes\n", pc87413_time);
 166 #endif
 167 }
 168
 169 /* Enable WDEN */
 170
 171 static inline void pc87413_enable_wden(unsigned int swc_base_addr)
 172 {
 173         /* Step 6: Enable WDEN */
 174
 175         outb_p(inb (swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
 176
 177 #ifdef DEBUG
 178         printk(KERN_INFO DPFX "Enable WDEN\n");
 179 #endif
 180 }
 181
 182 /* Enable SW_WD_TREN */
 183 static inline void pc87413_enable_sw_wd_tren(unsigned int swc_base_addr)
 184 {
 185         /* Enable SW_WD_TREN */
 186
 187         outb_p(inb (swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
 188
 189 #ifdef DEBUG
 190         printk(KERN_INFO DPFX "Enable SW_WD_TREN\n");
 191 #endif
 192 }
 193
 194 /* Disable SW_WD_TREN */
 195
 196 static inline void pc87413_disable_sw_wd_tren(unsigned int swc_base_addr)
 197 {
 198         /* Disable SW_WD_TREN */
 199
 200         outb_p(inb (swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
 201
 202 #ifdef DEBUG
 203         printk(KERN_INFO DPFX "pc87413 - Disable SW_WD_TREN\n");
 204 #endif
 205 }
 206
 207 /* Enable SW_WD_TRG */
 208
 209 static inline void pc87413_enable_sw_wd_trg(unsigned int swc_base_addr)
 210 {
 211         /* Enable SW_WD_TRG */
 212
 213         outb_p(inb (swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
 214
 215 #ifdef DEBUG
 216         printk(KERN_INFO DPFX "pc87413 - Enable SW_WD_TRG\n");
 217 #endif
 218 }
 219
 220 /* Disable SW_WD_TRG */
 221
 222 static inline void pc87413_disable_sw_wd_trg(unsigned int swc_base_addr)
 223 {
 224         /* Disable SW_WD_TRG */
 225
 226         outb_p(inb (swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
 227
 228 #ifdef DEBUG
 229         printk(KERN_INFO DPFX "Disable SW_WD_TRG\n");
 230 #endif
 231 }
 232
 233 /* -- Higher level functions ------------------------------------*/
 234
 235 /* Enable the watchdog */
 236
 237 static void pc87413_enable(void)
 238 {
 239         unsigned int swc_base_addr;
 240
 241         spin_lock(&io_lock);
 242
 243         pc87413_select_wdt_out();
 244         pc87413_enable_swc();
 245         swc_base_addr = pc87413_get_swc_base();
 246         pc87413_swc_bank3(swc_base_addr);
 247         pc87413_programm_wdto(swc_base_addr, timeout);
 248         pc87413_enable_wden(swc_base_addr);
 249         pc87413_enable_sw_wd_tren(swc_base_addr);
 250         pc87413_enable_sw_wd_trg(swc_base_addr);
 251
 252         spin_unlock(&io_lock);
 253 }
 254
 255 /* Disable the watchdog */
 256
 257 static void pc87413_disable(void)
 258 {
 259         unsigned int swc_base_addr;
 260
 261         spin_lock(&io_lock);
 262
 263         pc87413_select_wdt_out();
 264         pc87413_enable_swc();
 265         swc_base_addr = pc87413_get_swc_base();
 266         pc87413_swc_bank3(swc_base_addr);
 267         pc87413_disable_sw_wd_tren(swc_base_addr);
 268         pc87413_disable_sw_wd_trg(swc_base_addr);
 269         pc87413_programm_wdto(swc_base_addr, 0);
 270
 271         spin_unlock(&io_lock);
 272 }
 273
 274 /* Refresh the watchdog */
 275
 276 static void pc87413_refresh(void)
 277 {
 278         unsigned int swc_base_addr;
 279
 280         spin_lock(&io_lock);
 281
 282         pc87413_select_wdt_out();
 283         pc87413_enable_swc();
 284         swc_base_addr = pc87413_get_swc_base();
 285         pc87413_swc_bank3(swc_base_addr);
 286         pc87413_disable_sw_wd_tren(swc_base_addr);
 287         pc87413_disable_sw_wd_trg(swc_base_addr);
 288         pc87413_programm_wdto(swc_base_addr, timeout);
 289         pc87413_enable_wden(swc_base_addr);
 290         pc87413_enable_sw_wd_tren(swc_base_addr);
 291         pc87413_enable_sw_wd_trg(swc_base_addr);
 292
 293         spin_unlock(&io_lock);
 294 }
 295
 296 /* -- File operations -------------------------------------------*/
 297
 298 /**
 299  *      pc87413_open:
 300  *      @inode: inode of device
 301  *      @file: file handle to device
 302  *
 303  */
 304
 305 static int pc87413_open(struct inode *inode, struct file *file)
 306 {
 307         /* /dev/watchdog can only be opened once */
 308
 309         if (test_and_set_bit(0, &timer_enabled))
 310                 return -EBUSY;
 311
 312         if (nowayout)
 313                 __module_get(THIS_MODULE);
 314
 315         /* Reload and activate timer */
 316         pc87413_refresh();
 317
 318         printk(KERN_INFO MODNAME "Watchdog enabled. Timeout set to"
 319                                  " %d minute(s).\n", timeout);
 320
 321         return nonseekable_open(inode, file);
 322 }
 323
 324 /**
 325  *      pc87413_release:
 326  *      @inode: inode to board
 327  *      @file: file handle to board
 328  *
 329  *      The watchdog has a configurable API. There is a religious dispute
 330  *      between people who want their watchdog to be able to shut down and
 331  *      those who want to be sure if the watchdog manager dies the machine
 332  *      reboots. In the former case we disable the counters, in the latter
 333  *      case you have to open it again very soon.
 334  */
 335
 336 static int pc87413_release(struct inode *inode, struct file *file)
 337 {
 338         /* Shut off the timer. */
 339
 340         if (expect_close == 42) {
 341                 pc87413_disable();
 342                 printk(KERN_INFO MODNAME "Watchdog disabled,"
 343                                          " sleeping again...\n");
 344         } else {
 345                 printk(KERN_CRIT MODNAME "Unexpected close, not stopping"
 346                                          " watchdog!\n");
 347                 pc87413_refresh();
 348         }
 349
 350         clear_bit(0, &timer_enabled);
 351         expect_close = 0;
 352
 353         return 0;
 354 }
 355
 356 /**
 357  *      pc87413_status:
 358  *
 359  *      return, if the watchdog is enabled (timeout is set...)
 360  */
 361
 362
 363 static int pc87413_status(void)
 364 {
 365           return 0; /* currently not supported */
 366 }
 367
 368 /**
 369  *      pc87413_write:
 370  *      @file: file handle to the watchdog
 371  *      @data: data buffer to write
 372  *      @len: length in bytes
 373  *      @ppos: pointer to the position to write. No seeks allowed
 374  *
 375  *      A write to a watchdog device is defined as a keepalive signal. Any
 376  *      write of data will do, as we we don't define content meaning.
 377  */
 378
 379 static ssize_t pc87413_write(struct file *file, const char __user *data,
 380                              size_t len, loff_t *ppos)
 381 {
 382         /* See if we got the magic character 'V' and reload the timer */
 383         if (len) {
 384                 if (!nowayout) {
 385                         size_t i;
 386
 387                         /* reset expect flag */
 388                         expect_close = 0;
 389
 390                         /* scan to see whether or not we got the magic character */
 391                         for (i = 0; i != len; i++) {
 392                                 char c;
 393                                 if (get_user(c, data+i))
 394                                         return -EFAULT;
 395                                 if (c == 'V')
 396                                         expect_close = 42;
 397                         }
 398                 }
 399
 400                 /* someone wrote to us, we should reload the timer */
 401                 pc87413_refresh();
 402         }
 403         return len;
 404 }
 405
 406 /**
 407  *      pc87413_ioctl:
 408  *      @inode: inode of the device
 409  *      @file: file handle to the device
 410  *      @cmd: watchdog command
 411  *      @arg: argument pointer
 412  *
 413  *      The watchdog API defines a common set of functions for all watchdogs
 414  *      according to their available features. We only actually usefully support
 415  *      querying capabilities and current status.
 416  */
 417
 418 static int pc87413_ioctl(struct inode *inode, struct file *file,
 419                          unsigned int cmd, unsigned long arg)
 420 {
 421         int new_timeout;
 422
 423         union {
 424                 struct watchdog_info __user *ident;
 425                 int __user *i;
 426         } uarg;
 427
 428         static struct watchdog_info ident = {
 429                 .options          = WDIOF_KEEPALIVEPING |
 430                                     WDIOF_SETTIMEOUT |
 431                                     WDIOF_MAGICCLOSE,
 432                 .firmware_version = 1,
 433                 .identity         = "PC87413(HF/F) watchdog"
 434         };
 435
 436         uarg.i = (int __user *)arg;
 437
 438         switch(cmd) {
 439                 default:
 440                         return -ENOTTY;
 441
 442                 case WDIOC_GETSUPPORT:
 443                         return copy_to_user(uarg.ident, &ident,
 444                                 sizeof(ident)) ? -EFAULT : 0;
 445
 446                 case WDIOC_GETSTATUS:
 447                         return put_user(pc87413_status(), uarg.i);
 448
 449                 case WDIOC_GETBOOTSTATUS:
 450                         return put_user(0, uarg.i);
 451
 452                 case WDIOC_KEEPALIVE:
 453                         pc87413_refresh();
 454 #ifdef DEBUG
 455                         printk(KERN_INFO DPFX "keepalive\n");
 456 #endif
 457                         return 0;
 458
 459                 case WDIOC_SETTIMEOUT:
 460                         if (get_user(new_timeout, uarg.i))
 461                                 return -EFAULT;
 462
 463                         // the API states this is given in secs
 464                         new_timeout /= 60;
 465
 466                         if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 467                                 return -EINVAL;
 468
 469                         timeout = new_timeout;
 470                         pc87413_refresh();
 471
 472                         // fall through and return the new timeout...
 473
 474                 case WDIOC_GETTIMEOUT:
 475
 476                         new_timeout = timeout * 60;
 477
 478                         return put_user(new_timeout, uarg.i);
 479
 480                 case WDIOC_SETOPTIONS:
 481                 {
 482                         int options, retval = -EINVAL;
 483
 484                         if (get_user(options, uarg.i))
 485                                 return -EFAULT;
 486
 487                         if (options & WDIOS_DISABLECARD) {
 488                                 pc87413_disable();
 489                                 retval = 0;
 490                         }
 491
 492                         if (options & WDIOS_ENABLECARD) {
 493                                 pc87413_enable();
 494                                 retval = 0;
 495                         }
 496
 497                         return retval;
 498                 }
 499         }
 500 }
 501
 502 /* -- Notifier funtions -----------------------------------------*/
 503
 504 /**
 505  *      notify_sys:
 506  *      @this: our notifier block
 507  *      @code: the event being reported
 508  *      @unused: unused
 509  *
 510  *      Our notifier is called on system shutdowns. We want to turn the card
 511  *      off at reboot otherwise the machine will reboot again during memory
 512  *      test or worse yet during the following fsck. This would suck, in fact
 513  *      trust me - if it happens it does suck.
 514  */
 515
 516 static int pc87413_notify_sys(struct notifier_block *this,
 517                               unsigned long code,
 518                               void *unused)
 519 {
 520         if (code == SYS_DOWN || code == SYS_HALT)
 521         {
 522                 /* Turn the card off */
 523                 pc87413_disable();
 524         }
 525         return NOTIFY_DONE;
 526 }
 527
 528 /* -- Module's structures ---------------------------------------*/
 529
 530 static struct file_operations pc87413_fops = {
 531         .owner          = THIS_MODULE,
 532         .llseek         = no_llseek,
 533         .write          = pc87413_write,
 534         .ioctl          = pc87413_ioctl,
 535         .open           = pc87413_open,
 536         .release        = pc87413_release,
 537 };
 538
 539 static struct notifier_block pc87413_notifier =
 540 {
 541         .notifier_call  = pc87413_notify_sys,
 542 };
 543
 544 static struct miscdevice pc87413_miscdev=
 545 {
 546         .minor          = WATCHDOG_MINOR,
 547         .name           = "watchdog",
 548         .fops           = &pc87413_fops
 549 };
 550
 551 /* -- Module init functions -------------------------------------*/
 552
 553 /**
 554  *      pc87413_init: module's "constructor"
 555  *
 556  *      Set up the WDT watchdog board. All we have to do is grab the
 557  *      resources we require and bitch if anyone beat us to them.
 558  *      The open() function will actually kick the board off.
 559  */
 560
 561 static int __init pc87413_init(void)
 562 {
 563         int ret;
 564
 565         spin_lock_init(&io_lock);
 566
 567         printk(KERN_INFO PFX "Version " VERSION " at io 0x%X\n", WDT_INDEX_IO_PORT);
 568
 569         /* request_region(io, 2, "pc87413"); */
 570
 571         ret = register_reboot_notifier(&pc87413_notifier);
 572         if (ret != 0) {
 573                 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
 574                         ret);
 575         }
 576
 577         ret = misc_register(&pc87413_miscdev);
 578
 579         if (ret != 0) {
 580                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 581                         WATCHDOG_MINOR, ret);
 582                 unregister_reboot_notifier(&pc87413_notifier);
 583                 return ret;
 584         }
 585
 586         printk(KERN_INFO PFX "initialized. timeout=%d min \n", timeout);
 587
 588         pc87413_enable();
 589
 590         return 0;
 591 }
 592
 593 /**
 594  *      pc87413_exit: module's "destructor"
 595  *
 596  *      Unload the watchdog. You cannot do this with any file handles open.
 597  *      If your watchdog is set to continue ticking on close and you unload
 598  *      it, well it keeps ticking. We won't get the interrupt but the board
 599  *      will not touch PC memory so all is fine. You just have to load a new
 600  *      module in 60 seconds or reboot.
 601  */
 602
 603 static void __exit pc87413_exit(void)
 604 {
 605         /* Stop the timer before we leave */
 606         if (!nowayout)
 607         {
 608                 pc87413_disable();
 609                 printk(KERN_INFO MODNAME "Watchdog disabled.\n");
 610         }
 611
 612         misc_deregister(&pc87413_miscdev);
 613         unregister_reboot_notifier(&pc87413_notifier);
 614         /* release_region(io,2); */
 615
 616         printk(MODNAME " watchdog component driver removed.\n");
 617 }
 618
 619 module_init(pc87413_init);
 620 module_exit(pc87413_exit);
 621
 622 MODULE_AUTHOR("Sven Anders <anders@anduras.de>, Marcus Junker <junker@anduras.de>,");
 623 MODULE_DESCRIPTION("PC87413 WDT driver");
 624 MODULE_LICENSE("GPL");
 625
 626 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 627
 628 module_param(io, int, 0);
 629 MODULE_PARM_DESC(io, MODNAME " I/O port (default: " __MODULE_STRING(io) ").");
 630
 631 module_param(timeout, int, 0);
 632 MODULE_PARM_DESC(timeout, "Watchdog timeout in minutes (default=" __MODULE_STRING(timeout) ").");
 633
 634 module_param(nowayout, int, 0);
 635 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
 636