linux/drivers/watchdog/pc87413_wdt.c
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   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
  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 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
  58static int io = IO_DEFAULT;
  59static int swc_base_addr = -1;
  60
  61static int timeout = DEFAULT_TIMEOUT;   /* timeout value */
  62static unsigned long timer_enabled;     /* is the timer enabled? */
  63
  64static char expect_close;               /* is the close expected? */
  65
  66static DEFINE_SPINLOCK(io_lock);        /* to guard us from io races */
  67
  68static bool nowayout = WATCHDOG_NOWAYOUT;
  69
  70/* -- Low level function ----------------------------------------*/
  71
  72/* Select pins for Watchdog output */
  73
  74static inline void pc87413_select_wdt_out(void)
  75{
  76        unsigned int cr_data = 0;
  77
  78        /* Step 1: Select multiple pin,pin55,as WDT output */
  79
  80        outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  81
  82        cr_data = inb(WDT_DATA_IO_PORT);
  83
  84        cr_data |= 0x80; /* Set Bit7 to 1*/
  85        outb_p(SIOCFG2, WDT_INDEX_IO_PORT);
  86
  87        outb_p(cr_data, WDT_DATA_IO_PORT);
  88
  89#ifdef DEBUG
  90        pr_info(DPFX
  91                "Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
  92                                                                cr_data);
  93#endif
  94}
  95
  96/* Enable SWC functions */
  97
  98static inline void pc87413_enable_swc(void)
  99{
 100        unsigned int cr_data = 0;
 101
 102        /* Step 2: Enable SWC functions */
 103
 104        outb_p(0x07, WDT_INDEX_IO_PORT);        /* Point SWC_LDN (LDN=4) */
 105        outb_p(SWC_LDN, WDT_DATA_IO_PORT);
 106
 107        outb_p(0x30, WDT_INDEX_IO_PORT);        /* Read Index 0x30 First */
 108        cr_data = inb(WDT_DATA_IO_PORT);
 109        cr_data |= 0x01;                        /* Set Bit0 to 1 */
 110        outb_p(0x30, WDT_INDEX_IO_PORT);
 111        outb_p(cr_data, WDT_DATA_IO_PORT);      /* Index0x30_bit0P1 */
 112
 113#ifdef DEBUG
 114        pr_info(DPFX "pc87413 - Enable SWC functions\n");
 115#endif
 116}
 117
 118/* Read SWC I/O base address */
 119
 120static void pc87413_get_swc_base_addr(void)
 121{
 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        pr_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}
 140
 141/* Select Bank 3 of SWC */
 142
 143static inline void pc87413_swc_bank3(void)
 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        pr_info(DPFX "Select Bank3 of SWC\n");
 149#endif
 150}
 151
 152/* Set watchdog timeout to x minutes */
 153
 154static inline void pc87413_programm_wdto(char pc87413_time)
 155{
 156        /* Step 5: Programm WDTO, Twd. */
 157        outb_p(pc87413_time, swc_base_addr + WDTO);
 158#ifdef DEBUG
 159        pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
 160#endif
 161}
 162
 163/* Enable WDEN */
 164
 165static inline void pc87413_enable_wden(void)
 166{
 167        /* Step 6: Enable WDEN */
 168        outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
 169#ifdef DEBUG
 170        pr_info(DPFX "Enable WDEN\n");
 171#endif
 172}
 173
 174/* Enable SW_WD_TREN */
 175static inline void pc87413_enable_sw_wd_tren(void)
 176{
 177        /* Enable SW_WD_TREN */
 178        outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
 179#ifdef DEBUG
 180        pr_info(DPFX "Enable SW_WD_TREN\n");
 181#endif
 182}
 183
 184/* Disable SW_WD_TREN */
 185
 186static inline void pc87413_disable_sw_wd_tren(void)
 187{
 188        /* Disable SW_WD_TREN */
 189        outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
 190#ifdef DEBUG
 191        pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
 192#endif
 193}
 194
 195/* Enable SW_WD_TRG */
 196
 197static inline void pc87413_enable_sw_wd_trg(void)
 198{
 199        /* Enable SW_WD_TRG */
 200        outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
 201#ifdef DEBUG
 202        pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
 203#endif
 204}
 205
 206/* Disable SW_WD_TRG */
 207
 208static inline void pc87413_disable_sw_wd_trg(void)
 209{
 210        /* Disable SW_WD_TRG */
 211        outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
 212#ifdef DEBUG
 213        pr_info(DPFX "Disable SW_WD_TRG\n");
 214#endif
 215}
 216
 217/* -- Higher level functions ------------------------------------*/
 218
 219/* Enable the watchdog */
 220
 221static void pc87413_enable(void)
 222{
 223        spin_lock(&io_lock);
 224
 225        pc87413_swc_bank3();
 226        pc87413_programm_wdto(timeout);
 227        pc87413_enable_wden();
 228        pc87413_enable_sw_wd_tren();
 229        pc87413_enable_sw_wd_trg();
 230
 231        spin_unlock(&io_lock);
 232}
 233
 234/* Disable the watchdog */
 235
 236static void pc87413_disable(void)
 237{
 238        spin_lock(&io_lock);
 239
 240        pc87413_swc_bank3();
 241        pc87413_disable_sw_wd_tren();
 242        pc87413_disable_sw_wd_trg();
 243        pc87413_programm_wdto(0);
 244
 245        spin_unlock(&io_lock);
 246}
 247
 248/* Refresh the watchdog */
 249
 250static void pc87413_refresh(void)
 251{
 252        spin_lock(&io_lock);
 253
 254        pc87413_swc_bank3();
 255        pc87413_disable_sw_wd_tren();
 256        pc87413_disable_sw_wd_trg();
 257        pc87413_programm_wdto(timeout);
 258        pc87413_enable_wden();
 259        pc87413_enable_sw_wd_tren();
 260        pc87413_enable_sw_wd_trg();
 261
 262        spin_unlock(&io_lock);
 263}
 264
 265/* -- File operations -------------------------------------------*/
 266
 267/**
 268 *      pc87413_open:
 269 *      @inode: inode of device
 270 *      @file: file handle to device
 271 *
 272 */
 273
 274static int pc87413_open(struct inode *inode, struct file *file)
 275{
 276        /* /dev/watchdog can only be opened once */
 277
 278        if (test_and_set_bit(0, &timer_enabled))
 279                return -EBUSY;
 280
 281        if (nowayout)
 282                __module_get(THIS_MODULE);
 283
 284        /* Reload and activate timer */
 285        pc87413_refresh();
 286
 287        pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
 288
 289        return nonseekable_open(inode, file);
 290}
 291
 292/**
 293 *      pc87413_release:
 294 *      @inode: inode to board
 295 *      @file: file handle to board
 296 *
 297 *      The watchdog has a configurable API. There is a religious dispute
 298 *      between people who want their watchdog to be able to shut down and
 299 *      those who want to be sure if the watchdog manager dies the machine
 300 *      reboots. In the former case we disable the counters, in the latter
 301 *      case you have to open it again very soon.
 302 */
 303
 304static int pc87413_release(struct inode *inode, struct file *file)
 305{
 306        /* Shut off the timer. */
 307
 308        if (expect_close == 42) {
 309                pc87413_disable();
 310                pr_info("Watchdog disabled, sleeping again...\n");
 311        } else {
 312                pr_crit("Unexpected close, not stopping watchdog!\n");
 313                pc87413_refresh();
 314        }
 315        clear_bit(0, &timer_enabled);
 316        expect_close = 0;
 317        return 0;
 318}
 319
 320/**
 321 *      pc87413_status:
 322 *
 323 *      return, if the watchdog is enabled (timeout is set...)
 324 */
 325
 326
 327static int pc87413_status(void)
 328{
 329          return 0; /* currently not supported */
 330}
 331
 332/**
 333 *      pc87413_write:
 334 *      @file: file handle to the watchdog
 335 *      @data: data buffer to write
 336 *      @len: length in bytes
 337 *      @ppos: pointer to the position to write. No seeks allowed
 338 *
 339 *      A write to a watchdog device is defined as a keepalive signal. Any
 340 *      write of data will do, as we we don't define content meaning.
 341 */
 342
 343static ssize_t pc87413_write(struct file *file, const char __user *data,
 344                             size_t len, loff_t *ppos)
 345{
 346        /* See if we got the magic character 'V' and reload the timer */
 347        if (len) {
 348                if (!nowayout) {
 349                        size_t i;
 350
 351                        /* reset expect flag */
 352                        expect_close = 0;
 353
 354                        /* scan to see whether or not we got the
 355                           magic character */
 356                        for (i = 0; i != len; i++) {
 357                                char c;
 358                                if (get_user(c, data + i))
 359                                        return -EFAULT;
 360                                if (c == 'V')
 361                                        expect_close = 42;
 362                        }
 363                }
 364
 365                /* someone wrote to us, we should reload the timer */
 366                pc87413_refresh();
 367        }
 368        return len;
 369}
 370
 371/**
 372 *      pc87413_ioctl:
 373 *      @file: file handle to the device
 374 *      @cmd: watchdog command
 375 *      @arg: argument pointer
 376 *
 377 *      The watchdog API defines a common set of functions for all watchdogs
 378 *      according to their available features. We only actually usefully support
 379 *      querying capabilities and current status.
 380 */
 381
 382static long pc87413_ioctl(struct file *file, unsigned int cmd,
 383                                                unsigned long arg)
 384{
 385        int new_timeout;
 386
 387        union {
 388                struct watchdog_info __user *ident;
 389                int __user *i;
 390        } uarg;
 391
 392        static const struct watchdog_info ident = {
 393                .options          = WDIOF_KEEPALIVEPING |
 394                                    WDIOF_SETTIMEOUT |
 395                                    WDIOF_MAGICCLOSE,
 396                .firmware_version = 1,
 397                .identity         = "PC87413(HF/F) watchdog",
 398        };
 399
 400        uarg.i = (int __user *)arg;
 401
 402        switch (cmd) {
 403        case WDIOC_GETSUPPORT:
 404                return copy_to_user(uarg.ident, &ident,
 405                                        sizeof(ident)) ? -EFAULT : 0;
 406        case WDIOC_GETSTATUS:
 407                return put_user(pc87413_status(), uarg.i);
 408        case WDIOC_GETBOOTSTATUS:
 409                return put_user(0, uarg.i);
 410        case WDIOC_SETOPTIONS:
 411        {
 412                int options, retval = -EINVAL;
 413                if (get_user(options, uarg.i))
 414                        return -EFAULT;
 415                if (options & WDIOS_DISABLECARD) {
 416                        pc87413_disable();
 417                        retval = 0;
 418                }
 419                if (options & WDIOS_ENABLECARD) {
 420                        pc87413_enable();
 421                        retval = 0;
 422                }
 423                return retval;
 424        }
 425        case WDIOC_KEEPALIVE:
 426                pc87413_refresh();
 427#ifdef DEBUG
 428                pr_info(DPFX "keepalive\n");
 429#endif
 430                return 0;
 431        case WDIOC_SETTIMEOUT:
 432                if (get_user(new_timeout, uarg.i))
 433                        return -EFAULT;
 434                /* the API states this is given in secs */
 435                new_timeout /= 60;
 436                if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 437                        return -EINVAL;
 438                timeout = new_timeout;
 439                pc87413_refresh();
 440                /* fall through and return the new timeout... */
 441        case WDIOC_GETTIMEOUT:
 442                new_timeout = timeout * 60;
 443                return put_user(new_timeout, uarg.i);
 444        default:
 445                return -ENOTTY;
 446        }
 447}
 448
 449/* -- Notifier funtions -----------------------------------------*/
 450
 451/**
 452 *      notify_sys:
 453 *      @this: our notifier block
 454 *      @code: the event being reported
 455 *      @unused: unused
 456 *
 457 *      Our notifier is called on system shutdowns. We want to turn the card
 458 *      off at reboot otherwise the machine will reboot again during memory
 459 *      test or worse yet during the following fsck. This would suck, in fact
 460 *      trust me - if it happens it does suck.
 461 */
 462
 463static int pc87413_notify_sys(struct notifier_block *this,
 464                              unsigned long code,
 465                              void *unused)
 466{
 467        if (code == SYS_DOWN || code == SYS_HALT)
 468                /* Turn the card off */
 469                pc87413_disable();
 470        return NOTIFY_DONE;
 471}
 472
 473/* -- Module's structures ---------------------------------------*/
 474
 475static const struct file_operations pc87413_fops = {
 476        .owner          = THIS_MODULE,
 477        .llseek         = no_llseek,
 478        .write          = pc87413_write,
 479        .unlocked_ioctl = pc87413_ioctl,
 480        .open           = pc87413_open,
 481        .release        = pc87413_release,
 482};
 483
 484static struct notifier_block pc87413_notifier = {
 485        .notifier_call  = pc87413_notify_sys,
 486};
 487
 488static struct miscdevice pc87413_miscdev = {
 489        .minor          = WATCHDOG_MINOR,
 490        .name           = "watchdog",
 491        .fops           = &pc87413_fops,
 492};
 493
 494/* -- Module init functions -------------------------------------*/
 495
 496/**
 497 *      pc87413_init: module's "constructor"
 498 *
 499 *      Set up the WDT watchdog board. All we have to do is grab the
 500 *      resources we require and bitch if anyone beat us to them.
 501 *      The open() function will actually kick the board off.
 502 */
 503
 504static int __init pc87413_init(void)
 505{
 506        int ret;
 507
 508        pr_info("Version " VERSION " at io 0x%X\n",
 509                                                        WDT_INDEX_IO_PORT);
 510
 511        if (!request_muxed_region(io, 2, MODNAME))
 512                return -EBUSY;
 513
 514        ret = register_reboot_notifier(&pc87413_notifier);
 515        if (ret != 0) {
 516                pr_err("cannot register reboot notifier (err=%d)\n", ret);
 517        }
 518
 519        ret = misc_register(&pc87413_miscdev);
 520        if (ret != 0) {
 521                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 522                       WATCHDOG_MINOR, ret);
 523                goto reboot_unreg;
 524        }
 525        pr_info("initialized. timeout=%d min\n", timeout);
 526
 527        pc87413_select_wdt_out();
 528        pc87413_enable_swc();
 529        pc87413_get_swc_base_addr();
 530
 531        if (!request_region(swc_base_addr, 0x20, MODNAME)) {
 532                pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
 533                ret = -EBUSY;
 534                goto misc_unreg;
 535        }
 536
 537        pc87413_enable();
 538
 539        release_region(io, 2);
 540        return 0;
 541
 542misc_unreg:
 543        misc_deregister(&pc87413_miscdev);
 544reboot_unreg:
 545        unregister_reboot_notifier(&pc87413_notifier);
 546        release_region(io, 2);
 547        return ret;
 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
 560static void __exit pc87413_exit(void)
 561{
 562        /* Stop the timer before we leave */
 563        if (!nowayout) {
 564                pc87413_disable();
 565                pr_info("Watchdog disabled\n");
 566        }
 567
 568        misc_deregister(&pc87413_miscdev);
 569        unregister_reboot_notifier(&pc87413_notifier);
 570        release_region(swc_base_addr, 0x20);
 571
 572        pr_info("watchdog component driver removed\n");
 573}
 574
 575module_init(pc87413_init);
 576module_exit(pc87413_exit);
 577
 578MODULE_AUTHOR("Sven Anders <anders@anduras.de>, "
 579                "Marcus Junker <junker@anduras.de>,");
 580MODULE_DESCRIPTION("PC87413 WDT driver");
 581MODULE_LICENSE("GPL");
 582
 583MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 584
 585module_param(io, int, 0);
 586MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
 587                                        __MODULE_STRING(IO_DEFAULT) ").");
 588
 589module_param(timeout, int, 0);
 590MODULE_PARM_DESC(timeout,
 591                "Watchdog timeout in minutes (default="
 592                                __MODULE_STRING(DEFAULT_TIMEOUT) ").");
 593
 594module_param(nowayout, bool, 0);
 595MODULE_PARM_DESC(nowayout,
 596                "Watchdog cannot be stopped once started (default="
 597                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 598
 599
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