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