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/io.h>
  34 #include <linux/uaccess.h>
  35
  36 #include <asm/system.h>
  37
  38 /* #define DEBUG 1 */
  39
  40 #define DEFAULT_TIMEOUT     1           /* 1 minute */
  41 #define MAX_TIMEOUT         255
  42
  43 #define VERSION             "1.1"
  44 #define MODNAME             "pc87413 WDT"
  45 #define PFX                 MODNAME ": "
  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
  60 static int timeout = DEFAULT_TIMEOUT;   /* timeout value */
  61 static unsigned long timer_enabled;     /* is the timer enabled? */
  62
  63 static char expect_close;               /* is the close expected? */
  64
  65 static DEFINE_SPINLOCK(io_lock);        /* to guard us 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
  90                 "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
  91                                                                 cr_data);
  92 #endif
  93 }
  94
  95 /* Enable SWC functions */
  96
  97 static inline void pc87413_enable_swc(void)
  98 {
  99         unsigned int cr_data = 0;
 100
 101         /* Step 2: Enable SWC functions */
 102
 103         outb_p(0x07, WDT_INDEX_IO_PORT);        /* Point SWC_LDN (LDN=4) */
 104         outb_p(SWC_LDN, WDT_DATA_IO_PORT);
 105
 106         outb_p(0x30, WDT_INDEX_IO_PORT);        /* Read Index 0x30 First */
 107         cr_data = inb(WDT_DATA_IO_PORT);
 108         cr_data |= 0x01;                        /* Set Bit0 to 1 */
 109         outb_p(0x30, WDT_INDEX_IO_PORT);
 110         outb_p(cr_data, WDT_DATA_IO_PORT);      /* Index0x30_bit0P1 */
 111
 112 #ifdef DEBUG
 113         printk(KERN_INFO DPFX "pc87413 - Enable SWC functions\n");
 114 #endif
 115 }
 116
 117 /* Read SWC I/O base address */
 118
 119 static inline unsigned int pc87413_get_swc_base(void)
 120 {
 121         unsigned int  swc_base_addr = 0;
 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         printk(KERN_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         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         outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
 148 #ifdef DEBUG
 149         printk(KERN_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(unsigned int swc_base_addr,
 156                                          char pc87413_time)
 157 {
 158         /* Step 5: Programm WDTO, Twd. */
 159         outb_p(pc87413_time, swc_base_addr + WDTO);
 160 #ifdef DEBUG
 161         printk(KERN_INFO DPFX "Set WDTO to %d minutes\n", pc87413_time);
 162 #endif
 163 }
 164
 165 /* Enable WDEN */
 166
 167 static inline void pc87413_enable_wden(unsigned int swc_base_addr)
 168 {
 169         /* Step 6: Enable WDEN */
 170         outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
 171 #ifdef DEBUG
 172         printk(KERN_INFO DPFX "Enable WDEN\n");
 173 #endif
 174 }
 175
 176 /* Enable SW_WD_TREN */
 177 static inline void pc87413_enable_sw_wd_tren(unsigned int swc_base_addr)
 178 {
 179         /* Enable SW_WD_TREN */
 180         outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
 181 #ifdef DEBUG
 182         printk(KERN_INFO DPFX "Enable SW_WD_TREN\n");
 183 #endif
 184 }
 185
 186 /* Disable SW_WD_TREN */
 187
 188 static inline void pc87413_disable_sw_wd_tren(unsigned int swc_base_addr)
 189 {
 190         /* Disable SW_WD_TREN */
 191         outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
 192 #ifdef DEBUG
 193         printk(KERN_INFO DPFX "pc87413 - Disable SW_WD_TREN\n");
 194 #endif
 195 }
 196
 197 /* Enable SW_WD_TRG */
 198
 199 static inline void pc87413_enable_sw_wd_trg(unsigned int swc_base_addr)
 200 {
 201         /* Enable SW_WD_TRG */
 202         outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
 203 #ifdef DEBUG
 204         printk(KERN_INFO DPFX "pc87413 - Enable SW_WD_TRG\n");
 205 #endif
 206 }
 207
 208 /* Disable SW_WD_TRG */
 209
 210 static inline void pc87413_disable_sw_wd_trg(unsigned int swc_base_addr)
 211 {
 212         /* Disable SW_WD_TRG */
 213         outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
 214 #ifdef DEBUG
 215         printk(KERN_INFO DPFX "Disable SW_WD_TRG\n");
 216 #endif
 217 }
 218
 219 /* -- Higher level functions ------------------------------------*/
 220
 221 /* Enable the watchdog */
 222
 223 static void pc87413_enable(void)
 224 {
 225         unsigned int swc_base_addr;
 226
 227         spin_lock(&io_lock);
 228
 229         pc87413_select_wdt_out();
 230         pc87413_enable_swc();
 231         swc_base_addr = pc87413_get_swc_base();
 232         pc87413_swc_bank3(swc_base_addr);
 233         pc87413_programm_wdto(swc_base_addr, timeout);
 234         pc87413_enable_wden(swc_base_addr);
 235         pc87413_enable_sw_wd_tren(swc_base_addr);
 236         pc87413_enable_sw_wd_trg(swc_base_addr);
 237
 238         spin_unlock(&io_lock);
 239 }
 240
 241 /* Disable the watchdog */
 242
 243 static void pc87413_disable(void)
 244 {
 245         unsigned int swc_base_addr;
 246
 247         spin_lock(&io_lock);
 248
 249         pc87413_select_wdt_out();
 250         pc87413_enable_swc();
 251         swc_base_addr = pc87413_get_swc_base();
 252         pc87413_swc_bank3(swc_base_addr);
 253         pc87413_disable_sw_wd_tren(swc_base_addr);
 254         pc87413_disable_sw_wd_trg(swc_base_addr);
 255         pc87413_programm_wdto(swc_base_addr, 0);
 256
 257         spin_unlock(&io_lock);
 258 }
 259
 260 /* Refresh the watchdog */
 261
 262 static void pc87413_refresh(void)
 263 {
 264         unsigned int swc_base_addr;
 265
 266         spin_lock(&io_lock);
 267
 268         pc87413_select_wdt_out();
 269         pc87413_enable_swc();
 270         swc_base_addr = pc87413_get_swc_base();
 271         pc87413_swc_bank3(swc_base_addr);
 272         pc87413_disable_sw_wd_tren(swc_base_addr);
 273         pc87413_disable_sw_wd_trg(swc_base_addr);
 274         pc87413_programm_wdto(swc_base_addr, timeout);
 275         pc87413_enable_wden(swc_base_addr);
 276         pc87413_enable_sw_wd_tren(swc_base_addr);
 277         pc87413_enable_sw_wd_trg(swc_base_addr);
 278
 279         spin_unlock(&io_lock);
 280 }
 281
 282 /* -- File operations -------------------------------------------*/
 283
 284 /**
 285  *      pc87413_open:
 286  *      @inode: inode of device
 287  *      @file: file handle to device
 288  *
 289  */
 290
 291 static int pc87413_open(struct inode *inode, struct file *file)
 292 {
 293         /* /dev/watchdog can only be opened once */
 294
 295         if (test_and_set_bit(0, &timer_enabled))
 296                 return -EBUSY;
 297
 298         if (nowayout)
 299                 __module_get(THIS_MODULE);
 300
 301         /* Reload and activate timer */
 302         pc87413_refresh();
 303
 304         printk(KERN_INFO MODNAME
 305                 "Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
 306
 307         return nonseekable_open(inode, file);
 308 }
 309
 310 /**
 311  *      pc87413_release:
 312  *      @inode: inode to board
 313  *      @file: file handle to board
 314  *
 315  *      The watchdog has a configurable API. There is a religious dispute
 316  *      between people who want their watchdog to be able to shut down and
 317  *      those who want to be sure if the watchdog manager dies the machine
 318  *      reboots. In the former case we disable the counters, in the latter
 319  *      case you have to open it again very soon.
 320  */
 321
 322 static int pc87413_release(struct inode *inode, struct file *file)
 323 {
 324         /* Shut off the timer. */
 325
 326         if (expect_close == 42) {
 327                 pc87413_disable();
 328                 printk(KERN_INFO MODNAME
 329                                 "Watchdog disabled, sleeping again...\n");
 330         } else {
 331                 printk(KERN_CRIT MODNAME
 332                                 "Unexpected close, not stopping watchdog!\n");
 333                 pc87413_refresh();
 334         }
 335         clear_bit(0, &timer_enabled);
 336         expect_close = 0;
 337         return 0;
 338 }
 339
 340 /**
 341  *      pc87413_status:
 342  *
 343  *      return, if the watchdog is enabled (timeout is set...)
 344  */
 345
 346
 347 static int pc87413_status(void)
 348 {
 349           return 0; /* currently not supported */
 350 }
 351
 352 /**
 353  *      pc87413_write:
 354  *      @file: file handle to the watchdog
 355  *      @data: data buffer to write
 356  *      @len: length in bytes
 357  *      @ppos: pointer to the position to write. No seeks allowed
 358  *
 359  *      A write to a watchdog device is defined as a keepalive signal. Any
 360  *      write of data will do, as we we don't define content meaning.
 361  */
 362
 363 static ssize_t pc87413_write(struct file *file, const char __user *data,
 364                              size_t len, loff_t *ppos)
 365 {
 366         /* See if we got the magic character 'V' and reload the timer */
 367         if (len) {
 368                 if (!nowayout) {
 369                         size_t i;
 370
 371                         /* reset expect flag */
 372                         expect_close = 0;
 373
 374                         /* scan to see whether or not we got the
 375                            magic character */
 376                         for (i = 0; i != len; i++) {
 377                                 char c;
 378                                 if (get_user(c, data + i))
 379                                         return -EFAULT;
 380                                 if (c == 'V')
 381                                         expect_close = 42;
 382                         }
 383                 }
 384
 385                 /* someone wrote to us, we should reload the timer */
 386                 pc87413_refresh();
 387         }
 388         return len;
 389 }
 390
 391 /**
 392  *      pc87413_ioctl:
 393  *      @file: file handle to the device
 394  *      @cmd: watchdog command
 395  *      @arg: argument pointer
 396  *
 397  *      The watchdog API defines a common set of functions for all watchdogs
 398  *      according to their available features. We only actually usefully support
 399  *      querying capabilities and current status.
 400  */
 401
 402 static long pc87413_ioctl(struct file *file, unsigned int cmd,
 403                                                 unsigned long arg)
 404 {
 405         int new_timeout;
 406
 407         union {
 408                 struct watchdog_info __user *ident;
 409                 int __user *i;
 410         } uarg;
 411
 412         static const struct watchdog_info ident = {
 413                 .options          = WDIOF_KEEPALIVEPING |
 414                                     WDIOF_SETTIMEOUT |
 415                                     WDIOF_MAGICCLOSE,
 416                 .firmware_version = 1,
 417                 .identity         = "PC87413(HF/F) watchdog",
 418         };
 419
 420         uarg.i = (int __user *)arg;
 421
 422         switch (cmd) {
 423         case WDIOC_GETSUPPORT:
 424                 return copy_to_user(uarg.ident, &ident,
 425                                         sizeof(ident)) ? -EFAULT : 0;
 426         case WDIOC_GETSTATUS:
 427                 return put_user(pc87413_status(), uarg.i);
 428         case WDIOC_GETBOOTSTATUS:
 429                 return put_user(0, uarg.i);
 430         case WDIOC_SETOPTIONS:
 431         {
 432                 int options, retval = -EINVAL;
 433                 if (get_user(options, uarg.i))
 434                         return -EFAULT;
 435                 if (options & WDIOS_DISABLECARD) {
 436                         pc87413_disable();
 437                         retval = 0;
 438                 }
 439                 if (options & WDIOS_ENABLECARD) {
 440                         pc87413_enable();
 441                         retval = 0;
 442                 }
 443                 return retval;
 444         }
 445         case WDIOC_KEEPALIVE:
 446                 pc87413_refresh();
 447 #ifdef DEBUG
 448                 printk(KERN_INFO DPFX "keepalive\n");
 449 #endif
 450                 return 0;
 451         case WDIOC_SETTIMEOUT:
 452                 if (get_user(new_timeout, uarg.i))
 453                         return -EFAULT;
 454                 /* the API states this is given in secs */
 455                 new_timeout /= 60;
 456                 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 457                         return -EINVAL;
 458                 timeout = new_timeout;
 459                 pc87413_refresh();
 460                 /* fall through and return the new timeout... */
 461         case WDIOC_GETTIMEOUT:
 462                 new_timeout = timeout * 60;
 463                 return put_user(new_timeout, uarg.i);
 464         default:
 465                 return -ENOTTY;
 466         }
 467 }
 468
 469 /* -- Notifier funtions -----------------------------------------*/
 470
 471 /**
 472  *      notify_sys:
 473  *      @this: our notifier block
 474  *      @code: the event being reported
 475  *      @unused: unused
 476  *
 477  *      Our notifier is called on system shutdowns. We want to turn the card
 478  *      off at reboot otherwise the machine will reboot again during memory
 479  *      test or worse yet during the following fsck. This would suck, in fact
 480  *      trust me - if it happens it does suck.
 481  */
 482
 483 static int pc87413_notify_sys(struct notifier_block *this,
 484                               unsigned long code,
 485                               void *unused)
 486 {
 487         if (code == SYS_DOWN || code == SYS_HALT)
 488                 /* Turn the card off */
 489                 pc87413_disable();
 490         return NOTIFY_DONE;
 491 }
 492
 493 /* -- Module's structures ---------------------------------------*/
 494
 495 static const struct file_operations pc87413_fops = {
 496         .owner          = THIS_MODULE,
 497         .llseek         = no_llseek,
 498         .write          = pc87413_write,
 499         .unlocked_ioctl = pc87413_ioctl,
 500         .open           = pc87413_open,
 501         .release        = pc87413_release,
 502 };
 503
 504 static struct notifier_block pc87413_notifier = {
 505         .notifier_call  = pc87413_notify_sys,
 506 };
 507
 508 static struct miscdevice pc87413_miscdev = {
 509         .minor          = WATCHDOG_MINOR,
 510         .name           = "watchdog",
 511         .fops           = &pc87413_fops,
 512 };
 513
 514 /* -- Module init functions -------------------------------------*/
 515
 516 /**
 517  *      pc87413_init: module's "constructor"
 518  *
 519  *      Set up the WDT watchdog board. All we have to do is grab the
 520  *      resources we require and bitch if anyone beat us to them.
 521  *      The open() function will actually kick the board off.
 522  */
 523
 524 static int __init pc87413_init(void)
 525 {
 526         int ret;
 527
 528         printk(KERN_INFO PFX "Version " VERSION " at io 0x%X\n",
 529                                                         WDT_INDEX_IO_PORT);
 530
 531         /* request_region(io, 2, "pc87413"); */
 532
 533         ret = register_reboot_notifier(&pc87413_notifier);
 534         if (ret != 0) {
 535                 printk(KERN_ERR PFX
 536                         "cannot register reboot notifier (err=%d)\n", ret);
 537         }
 538
 539         ret = misc_register(&pc87413_miscdev);
 540         if (ret != 0) {
 541                 printk(KERN_ERR PFX
 542                         "cannot register miscdev on minor=%d (err=%d)\n",
 543                         WATCHDOG_MINOR, ret);
 544                 unregister_reboot_notifier(&pc87413_notifier);
 545                 return ret;
 546         }
 547         printk(KERN_INFO PFX "initialized. timeout=%d min \n", timeout);
 548         pc87413_enable();
 549         return 0;
 550 }
 551
 552 /**
 553  *      pc87413_exit: module's "destructor"
 554  *
 555  *      Unload the watchdog. You cannot do this with any file handles open.
 556  *      If your watchdog is set to continue ticking on close and you unload
 557  *      it, well it keeps ticking. We won't get the interrupt but the board
 558  *      will not touch PC memory so all is fine. You just have to load a new
 559  *      module in 60 seconds or reboot.
 560  */
 561
 562 static void __exit pc87413_exit(void)
 563 {
 564         /* Stop the timer before we leave */
 565         if (!nowayout) {
 566                 pc87413_disable();
 567                 printk(KERN_INFO MODNAME "Watchdog disabled.\n");
 568         }
 569
 570         misc_deregister(&pc87413_miscdev);
 571         unregister_reboot_notifier(&pc87413_notifier);
 572         /* release_region(io, 2); */
 573
 574         printk(KERN_INFO MODNAME " watchdog component driver removed.\n");
 575 }
 576
 577 module_init(pc87413_init);
 578 module_exit(pc87413_exit);
 579
 580 MODULE_AUTHOR("Sven Anders <anders@anduras.de>, "
 581                 "Marcus Junker <junker@anduras.de>,");
 582 MODULE_DESCRIPTION("PC87413 WDT driver");
 583 MODULE_LICENSE("GPL");
 584
 585 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 586
 587 module_param(io, int, 0);
 588 MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
 589                                         __MODULE_STRING(IO_DEFAULT) ").");
 590
 591 module_param(timeout, int, 0);
 592 MODULE_PARM_DESC(timeout,
 593                 "Watchdog timeout in minutes (default="
 594                                 __MODULE_STRING(DEFAULT_TIMEOUT) ").");
 595
 596 module_param(nowayout, int, 0);
 597 MODULE_PARM_DESC(nowayout,
 598                 "Watchdog cannot be stopped once started (default="
 599                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 600