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