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 #include <linux/io.h>
  35 #include <linux/uaccess.h>
  36
  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;     /* is the timer enabled? */
  61
  62 static char expect_close;               /* is the close expected? */
  63
  64 static DEFINE_SPINLOCK(io_lock);        /* to guard us 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
  89                 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
  90                                                                 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 #ifdef DEBUG
 134         printk(KERN_INFO DPFX
 135                 "Read SWC I/O Base Address: low %d, high %d, res %d\n",
 136                                                 addr_l, addr_h, swc_base_addr);
 137 #endif
 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         outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
 147 #ifdef DEBUG
 148         printk(KERN_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(unsigned int swc_base_addr,
 155                                          char pc87413_time)
 156 {
 157         /* Step 5: Programm WDTO, Twd. */
 158         outb_p(pc87413_time, swc_base_addr + WDTO);
 159 #ifdef DEBUG
 160         printk(KERN_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(unsigned int swc_base_addr)
 167 {
 168         /* Step 6: Enable WDEN */
 169         outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
 170 #ifdef DEBUG
 171         printk(KERN_INFO DPFX "Enable WDEN\n");
 172 #endif
 173 }
 174
 175 /* Enable SW_WD_TREN */
 176 static inline void pc87413_enable_sw_wd_tren(unsigned int swc_base_addr)
 177 {
 178         /* Enable SW_WD_TREN */
 179         outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
 180 #ifdef DEBUG
 181         printk(KERN_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(unsigned int swc_base_addr)
 188 {
 189         /* Disable SW_WD_TREN */
 190         outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
 191 #ifdef DEBUG
 192         printk(KERN_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(unsigned int swc_base_addr)
 199 {
 200         /* Enable SW_WD_TRG */
 201         outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
 202 #ifdef DEBUG
 203         printk(KERN_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(unsigned int swc_base_addr)
 210 {
 211         /* Disable SW_WD_TRG */
 212         outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
 213 #ifdef DEBUG
 214         printk(KERN_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         unsigned int swc_base_addr;
 225
 226         spin_lock(&io_lock);
 227
 228         pc87413_select_wdt_out();
 229         pc87413_enable_swc();
 230         swc_base_addr = pc87413_get_swc_base();
 231         pc87413_swc_bank3(swc_base_addr);
 232         pc87413_programm_wdto(swc_base_addr, timeout);
 233         pc87413_enable_wden(swc_base_addr);
 234         pc87413_enable_sw_wd_tren(swc_base_addr);
 235         pc87413_enable_sw_wd_trg(swc_base_addr);
 236
 237         spin_unlock(&io_lock);
 238 }
 239
 240 /* Disable the watchdog */
 241
 242 static void pc87413_disable(void)
 243 {
 244         unsigned int swc_base_addr;
 245
 246         spin_lock(&io_lock);
 247
 248         pc87413_select_wdt_out();
 249         pc87413_enable_swc();
 250         swc_base_addr = pc87413_get_swc_base();
 251         pc87413_swc_bank3(swc_base_addr);
 252         pc87413_disable_sw_wd_tren(swc_base_addr);
 253         pc87413_disable_sw_wd_trg(swc_base_addr);
 254         pc87413_programm_wdto(swc_base_addr, 0);
 255
 256         spin_unlock(&io_lock);
 257 }
 258
 259 /* Refresh the watchdog */
 260
 261 static void pc87413_refresh(void)
 262 {
 263         unsigned int swc_base_addr;
 264
 265         spin_lock(&io_lock);
 266
 267         pc87413_select_wdt_out();
 268         pc87413_enable_swc();
 269         swc_base_addr = pc87413_get_swc_base();
 270         pc87413_swc_bank3(swc_base_addr);
 271         pc87413_disable_sw_wd_tren(swc_base_addr);
 272         pc87413_disable_sw_wd_trg(swc_base_addr);
 273         pc87413_programm_wdto(swc_base_addr, timeout);
 274         pc87413_enable_wden(swc_base_addr);
 275         pc87413_enable_sw_wd_tren(swc_base_addr);
 276         pc87413_enable_sw_wd_trg(swc_base_addr);
 277
 278         spin_unlock(&io_lock);
 279 }
 280
 281 /* -- File operations -------------------------------------------*/
 282
 283 /**
 284  *      pc87413_open:
 285  *      @inode: inode of device
 286  *      @file: file handle to device
 287  *
 288  */
 289
 290 static int pc87413_open(struct inode *inode, struct file *file)
 291 {
 292         /* /dev/watchdog can only be opened once */
 293
 294         if (test_and_set_bit(0, &timer_enabled))
 295                 return -EBUSY;
 296
 297         if (nowayout)
 298                 __module_get(THIS_MODULE);
 299
 300         /* Reload and activate timer */
 301         pc87413_refresh();
 302
 303         printk(KERN_INFO MODNAME
 304                 "Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
 305
 306         return nonseekable_open(inode, file);
 307 }
 308
 309 /**
 310  *      pc87413_release:
 311  *      @inode: inode to board
 312  *      @file: file handle to board
 313  *
 314  *      The watchdog has a configurable API. There is a religious dispute
 315  *      between people who want their watchdog to be able to shut down and
 316  *      those who want to be sure if the watchdog manager dies the machine
 317  *      reboots. In the former case we disable the counters, in the latter
 318  *      case you have to open it again very soon.
 319  */
 320
 321 static int pc87413_release(struct inode *inode, struct file *file)
 322 {
 323         /* Shut off the timer. */
 324
 325         if (expect_close == 42) {
 326                 pc87413_disable();
 327                 printk(KERN_INFO MODNAME
 328                                 "Watchdog disabled, sleeping again...\n");
 329         } else {
 330                 printk(KERN_CRIT MODNAME
 331                                 "Unexpected close, not stopping watchdog!\n");
 332                 pc87413_refresh();
 333         }
 334         clear_bit(0, &timer_enabled);
 335         expect_close = 0;
 336         return 0;
 337 }
 338
 339 /**
 340  *      pc87413_status:
 341  *
 342  *      return, if the watchdog is enabled (timeout is set...)
 343  */
 344
 345
 346 static int pc87413_status(void)
 347 {
 348           return 0; /* currently not supported */
 349 }
 350
 351 /**
 352  *      pc87413_write:
 353  *      @file: file handle to the watchdog
 354  *      @data: data buffer to write
 355  *      @len: length in bytes
 356  *      @ppos: pointer to the position to write. No seeks allowed
 357  *
 358  *      A write to a watchdog device is defined as a keepalive signal. Any
 359  *      write of data will do, as we we don't define content meaning.
 360  */
 361
 362 static ssize_t pc87413_write(struct file *file, const char __user *data,
 363                              size_t len, loff_t *ppos)
 364 {
 365         /* See if we got the magic character 'V' and reload the timer */
 366         if (len) {
 367                 if (!nowayout) {
 368                         size_t i;
 369
 370                         /* reset expect flag */
 371                         expect_close = 0;
 372
 373                         /* scan to see whether or not we got the
 374                            magic character */
 375                         for (i = 0; i != len; i++) {
 376                                 char c;
 377                                 if (get_user(c, data + i))
 378                                         return -EFAULT;
 379                                 if (c == 'V')
 380                                         expect_close = 42;
 381                         }
 382                 }
 383
 384                 /* someone wrote to us, we should reload the timer */
 385                 pc87413_refresh();
 386         }
 387         return len;
 388 }
 389
 390 /**
 391  *      pc87413_ioctl:
 392  *      @file: file handle to the device
 393  *      @cmd: watchdog command
 394  *      @arg: argument pointer
 395  *
 396  *      The watchdog API defines a common set of functions for all watchdogs
 397  *      according to their available features. We only actually usefully support
 398  *      querying capabilities and current status.
 399  */
 400
 401 static long pc87413_ioctl(struct file *file, unsigned int cmd,
 402                                                 unsigned long arg)
 403 {
 404         int new_timeout;
 405
 406         union {
 407                 struct watchdog_info __user *ident;
 408                 int __user *i;
 409         } uarg;
 410
 411         static struct watchdog_info ident = {
 412                 .options          = WDIOF_KEEPALIVEPING |
 413                                     WDIOF_SETTIMEOUT |
 414                                     WDIOF_MAGICCLOSE,
 415                 .firmware_version = 1,
 416                 .identity         = "PC87413(HF/F) watchdog",
 417         };
 418
 419         uarg.i = (int __user *)arg;
 420
 421         switch (cmd) {
 422         case WDIOC_GETSUPPORT:
 423                 return copy_to_user(uarg.ident, &ident,
 424                                         sizeof(ident)) ? -EFAULT : 0;
 425         case WDIOC_GETSTATUS:
 426                 return put_user(pc87413_status(), uarg.i);
 427         case WDIOC_GETBOOTSTATUS:
 428                 return put_user(0, uarg.i);
 429         case WDIOC_SETOPTIONS:
 430         {
 431                 int options, retval = -EINVAL;
 432                 if (get_user(options, uarg.i))
 433                         return -EFAULT;
 434                 if (options & WDIOS_DISABLECARD) {
 435                         pc87413_disable();
 436                         retval = 0;
 437                 }
 438                 if (options & WDIOS_ENABLECARD) {
 439                         pc87413_enable();
 440                         retval = 0;
 441                 }
 442                 return retval;
 443         }
 444         case WDIOC_KEEPALIVE:
 445                 pc87413_refresh();
 446 #ifdef DEBUG
 447                 printk(KERN_INFO DPFX "keepalive\n");
 448 #endif
 449                 return 0;
 450         case WDIOC_SETTIMEOUT:
 451                 if (get_user(new_timeout, uarg.i))
 452                         return -EFAULT;
 453                 /* the API states this is given in secs */
 454                 new_timeout /= 60;
 455                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 456                         return -EINVAL;
 457                 timeout = new_timeout;
 458                 pc87413_refresh();
 459                 /* fall through and return the new timeout... */
 460         case WDIOC_GETTIMEOUT:
 461                 new_timeout = timeout * 60;
 462                 return put_user(new_timeout, uarg.i);
 463         default:
 464                 return -ENOTTY;
 465         }
 466 }
 467
 468 /* -- Notifier funtions -----------------------------------------*/
 469
 470 /**
 471  *      notify_sys:
 472  *      @this: our notifier block
 473  *      @code: the event being reported
 474  *      @unused: unused
 475  *
 476  *      Our notifier is called on system shutdowns. We want to turn the card
 477  *      off at reboot otherwise the machine will reboot again during memory
 478  *      test or worse yet during the following fsck. This would suck, in fact
 479  *      trust me - if it happens it does suck.
 480  */
 481
 482 static int pc87413_notify_sys(struct notifier_block *this,
 483                               unsigned long code,
 484                               void *unused)
 485 {
 486         if (code == SYS_DOWN || code == SYS_HALT)
 487                 /* Turn the card off */
 488                 pc87413_disable();
 489         return NOTIFY_DONE;
 490 }
 491
 492 /* -- Module's structures ---------------------------------------*/
 493
 494 static const struct file_operations pc87413_fops = {
 495         .owner          = THIS_MODULE,
 496         .llseek         = no_llseek,
 497         .write          = pc87413_write,
 498         .unlocked_ioctl = pc87413_ioctl,
 499         .open           = pc87413_open,
 500         .release        = pc87413_release,
 501 };
 502
 503 static struct notifier_block pc87413_notifier = {
 504         .notifier_call  = pc87413_notify_sys,
 505 };
 506
 507 static struct miscdevice pc87413_miscdev = {
 508         .minor          = WATCHDOG_MINOR,
 509         .name           = "watchdog",
 510         .fops           = &pc87413_fops,
 511 };
 512
 513 /* -- Module init functions -------------------------------------*/
 514
 515 /**
 516  *      pc87413_init: module's "constructor"
 517  *
 518  *      Set up the WDT watchdog board. All we have to do is grab the
 519  *      resources we require and bitch if anyone beat us to them.
 520  *      The open() function will actually kick the board off.
 521  */
 522
 523 static int __init pc87413_init(void)
 524 {
 525         int ret;
 526
 527         printk(KERN_INFO PFX "Version " VERSION " at io 0x%X\n",
 528                                                         WDT_INDEX_IO_PORT);
 529
 530         /* request_region(io, 2, "pc87413"); */
 531
 532         ret = register_reboot_notifier(&pc87413_notifier);
 533         if (ret != 0) {
 534                 printk(KERN_ERR PFX
 535                         "cannot register reboot notifier (err=%d)\n", ret);
 536         }
 537
 538         ret = misc_register(&pc87413_miscdev);
 539         if (ret != 0) {
 540                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 541                         WATCHDOG_MINOR, ret);
 542                 unregister_reboot_notifier(&pc87413_notifier);
 543                 return ret;
 544         }
 545         printk(KERN_INFO PFX "initialized. timeout=%d min \n", timeout);
 546         pc87413_enable();
 547         return 0;
 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                 printk(KERN_INFO MODNAME "Watchdog disabled.\n");
 566         }
 567
 568         misc_deregister(&pc87413_miscdev);
 569         unregister_reboot_notifier(&pc87413_notifier);
 570         /* release_region(io, 2); */
 571
 572         printk(KERN_INFO MODNAME " 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>, Marcus Junker <junker@anduras.de>,");
 579 MODULE_DESCRIPTION("PC87413 WDT driver");
 580 MODULE_LICENSE("GPL");
 581
 582 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 583
 584 module_param(io, int, 0);
 585 MODULE_PARM_DESC(io, MODNAME " I/O port (default: " __MODULE_STRING(io) ").");
 586
 587 module_param(timeout, int, 0);
 588 MODULE_PARM_DESC(timeout,
 589                 "Watchdog timeout in minutes (default="
 590                                 __MODULE_STRING(timeout) ").");
 591
 592 module_param(nowayout, int, 0);
 593 MODULE_PARM_DESC(nowayout,
 594                 "Watchdog cannot be stopped once started (default="
 595                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 596