linux/drivers/watchdog/sc1200wdt.c
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   1/*
   2 *      National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
   3 *      (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>,
   4 *                      All Rights Reserved.
   5 *      Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
   6 *
   7 *      This program is free software; you can redistribute it and/or
   8 *      modify it under the terms of the GNU General Public License
   9 *      as published by the Free Software Foundation; either version
  10 *      2 of the License, or (at your option) any later version.
  11 *
  12 *      The author(s) of this software shall not be held liable for damages
  13 *      of any nature resulting due to the use of this software. This
  14 *      software is provided AS-IS with no warranties.
  15 *
  16 *      Changelog:
  17 *      20020220 Zwane Mwaikambo        Code based on datasheet, no hardware.
  18 *      20020221 Zwane Mwaikambo        Cleanups as suggested by Jeff Garzik
  19 *                                      and Alan Cox.
  20 *      20020222 Zwane Mwaikambo        Added probing.
  21 *      20020225 Zwane Mwaikambo        Added ISAPNP support.
  22 *      20020412 Rob Radez              Broke out start/stop functions
  23 *               <rob@osinvestor.com>   Return proper status instead of
  24 *                                      temperature warning
  25 *                                      Add WDIOC_GETBOOTSTATUS and
  26 *                                      WDIOC_SETOPTIONS ioctls
  27 *                                      Fix CONFIG_WATCHDOG_NOWAYOUT
  28 *      20020530 Joel Becker            Add Matt Domsch's nowayout module
  29 *                                      option
  30 *      20030116 Adam Belay             Updated to the latest pnp code
  31 *
  32 */
  33
  34#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  35
  36#include <linux/module.h>
  37#include <linux/moduleparam.h>
  38#include <linux/miscdevice.h>
  39#include <linux/watchdog.h>
  40#include <linux/ioport.h>
  41#include <linux/spinlock.h>
  42#include <linux/notifier.h>
  43#include <linux/reboot.h>
  44#include <linux/init.h>
  45#include <linux/pnp.h>
  46#include <linux/fs.h>
  47#include <linux/semaphore.h>
  48#include <linux/io.h>
  49#include <linux/uaccess.h>
  50
  51#define SC1200_MODULE_VER       "build 20020303"
  52#define SC1200_MODULE_NAME      "sc1200wdt"
  53
  54#define MAX_TIMEOUT     255     /* 255 minutes */
  55#define PMIR            (io)    /* Power Management Index Register */
  56#define PMDR            (io+1)  /* Power Management Data Register */
  57
  58/* Data Register indexes */
  59#define FER1            0x00    /* Function enable register 1 */
  60#define FER2            0x01    /* Function enable register 2 */
  61#define PMC1            0x02    /* Power Management Ctrl 1 */
  62#define PMC2            0x03    /* Power Management Ctrl 2 */
  63#define PMC3            0x04    /* Power Management Ctrl 3 */
  64#define WDTO            0x05    /* Watchdog timeout register */
  65#define WDCF            0x06    /* Watchdog config register */
  66#define WDST            0x07    /* Watchdog status register */
  67
  68/* WDCF bitfields - which devices assert WDO */
  69#define KBC_IRQ         0x01    /* Keyboard Controller */
  70#define MSE_IRQ         0x02    /* Mouse */
  71#define UART1_IRQ       0x03    /* Serial0 */
  72#define UART2_IRQ       0x04    /* Serial1 */
  73/* 5 -7 are reserved */
  74
  75static int timeout = 1;
  76static int io = -1;
  77static int io_len = 2;          /* for non plug and play */
  78static unsigned long open_flag;
  79static char expect_close;
  80static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */
  81
  82#if defined CONFIG_PNP
  83static int isapnp = 1;
  84static struct pnp_dev *wdt_dev;
  85
  86module_param(isapnp, int, 0);
  87MODULE_PARM_DESC(isapnp,
  88        "When set to 0 driver ISA PnP support will be disabled");
  89#endif
  90
  91module_param(io, int, 0);
  92MODULE_PARM_DESC(io, "io port");
  93module_param(timeout, int, 0);
  94MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
  95
  96static bool nowayout = WATCHDOG_NOWAYOUT;
  97module_param(nowayout, bool, 0);
  98MODULE_PARM_DESC(nowayout,
  99        "Watchdog cannot be stopped once started (default="
 100                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 101
 102
 103
 104/* Read from Data Register */
 105static inline void __sc1200wdt_read_data(unsigned char index,
 106                                                unsigned char *data)
 107{
 108        outb_p(index, PMIR);
 109        *data = inb(PMDR);
 110}
 111
 112static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
 113{
 114        spin_lock(&sc1200wdt_lock);
 115        __sc1200wdt_read_data(index, data);
 116        spin_unlock(&sc1200wdt_lock);
 117}
 118
 119/* Write to Data Register */
 120static inline void __sc1200wdt_write_data(unsigned char index,
 121                                                unsigned char data)
 122{
 123        outb_p(index, PMIR);
 124        outb(data, PMDR);
 125}
 126
 127static inline void sc1200wdt_write_data(unsigned char index,
 128                                                unsigned char data)
 129{
 130        spin_lock(&sc1200wdt_lock);
 131        __sc1200wdt_write_data(index, data);
 132        spin_unlock(&sc1200wdt_lock);
 133}
 134
 135
 136static void sc1200wdt_start(void)
 137{
 138        unsigned char reg;
 139        spin_lock(&sc1200wdt_lock);
 140
 141        __sc1200wdt_read_data(WDCF, &reg);
 142        /* assert WDO when any of the following interrupts are triggered too */
 143        reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
 144        __sc1200wdt_write_data(WDCF, reg);
 145        /* set the timeout and get the ball rolling */
 146        __sc1200wdt_write_data(WDTO, timeout);
 147
 148        spin_unlock(&sc1200wdt_lock);
 149}
 150
 151static void sc1200wdt_stop(void)
 152{
 153        sc1200wdt_write_data(WDTO, 0);
 154}
 155
 156/* This returns the status of the WDO signal, inactive high. */
 157static inline int sc1200wdt_status(void)
 158{
 159        unsigned char ret;
 160
 161        sc1200wdt_read_data(WDST, &ret);
 162        /* If the bit is inactive, the watchdog is enabled, so return
 163         * KEEPALIVEPING which is a bit of a kludge because there's nothing
 164         * else for enabled/disabled status
 165         */
 166        return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
 167}
 168
 169static int sc1200wdt_open(struct inode *inode, struct file *file)
 170{
 171        /* allow one at a time */
 172        if (test_and_set_bit(0, &open_flag))
 173                return -EBUSY;
 174
 175        if (timeout > MAX_TIMEOUT)
 176                timeout = MAX_TIMEOUT;
 177
 178        sc1200wdt_start();
 179        pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
 180
 181        return nonseekable_open(inode, file);
 182}
 183
 184
 185static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
 186                                                unsigned long arg)
 187{
 188        int new_timeout;
 189        void __user *argp = (void __user *)arg;
 190        int __user *p = argp;
 191        static const struct watchdog_info ident = {
 192                .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
 193                                                        WDIOF_MAGICCLOSE,
 194                .firmware_version = 0,
 195                .identity = "PC87307/PC97307",
 196        };
 197
 198        switch (cmd) {
 199        case WDIOC_GETSUPPORT:
 200                if (copy_to_user(argp, &ident, sizeof(ident)))
 201                        return -EFAULT;
 202                return 0;
 203
 204        case WDIOC_GETSTATUS:
 205                return put_user(sc1200wdt_status(), p);
 206
 207        case WDIOC_GETBOOTSTATUS:
 208                return put_user(0, p);
 209
 210        case WDIOC_SETOPTIONS:
 211        {
 212                int options, retval = -EINVAL;
 213
 214                if (get_user(options, p))
 215                        return -EFAULT;
 216
 217                if (options & WDIOS_DISABLECARD) {
 218                        sc1200wdt_stop();
 219                        retval = 0;
 220                }
 221
 222                if (options & WDIOS_ENABLECARD) {
 223                        sc1200wdt_start();
 224                        retval = 0;
 225                }
 226
 227                return retval;
 228        }
 229        case WDIOC_KEEPALIVE:
 230                sc1200wdt_write_data(WDTO, timeout);
 231                return 0;
 232
 233        case WDIOC_SETTIMEOUT:
 234                if (get_user(new_timeout, p))
 235                        return -EFAULT;
 236                /* the API states this is given in secs */
 237                new_timeout /= 60;
 238                if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
 239                        return -EINVAL;
 240                timeout = new_timeout;
 241                sc1200wdt_write_data(WDTO, timeout);
 242                /* fall through and return the new timeout */
 243
 244        case WDIOC_GETTIMEOUT:
 245                return put_user(timeout * 60, p);
 246
 247        default:
 248                return -ENOTTY;
 249        }
 250}
 251
 252
 253static int sc1200wdt_release(struct inode *inode, struct file *file)
 254{
 255        if (expect_close == 42) {
 256                sc1200wdt_stop();
 257                pr_info("Watchdog disabled\n");
 258        } else {
 259                sc1200wdt_write_data(WDTO, timeout);
 260                pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
 261        }
 262        clear_bit(0, &open_flag);
 263        expect_close = 0;
 264
 265        return 0;
 266}
 267
 268
 269static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
 270                                                size_t len, loff_t *ppos)
 271{
 272        if (len) {
 273                if (!nowayout) {
 274                        size_t i;
 275
 276                        expect_close = 0;
 277
 278                        for (i = 0; i != len; i++) {
 279                                char c;
 280
 281                                if (get_user(c, data + i))
 282                                        return -EFAULT;
 283                                if (c == 'V')
 284                                        expect_close = 42;
 285                        }
 286                }
 287
 288                sc1200wdt_write_data(WDTO, timeout);
 289                return len;
 290        }
 291
 292        return 0;
 293}
 294
 295
 296static int sc1200wdt_notify_sys(struct notifier_block *this,
 297                                        unsigned long code, void *unused)
 298{
 299        if (code == SYS_DOWN || code == SYS_HALT)
 300                sc1200wdt_stop();
 301
 302        return NOTIFY_DONE;
 303}
 304
 305
 306static struct notifier_block sc1200wdt_notifier = {
 307        .notifier_call =        sc1200wdt_notify_sys,
 308};
 309
 310static const struct file_operations sc1200wdt_fops = {
 311        .owner          = THIS_MODULE,
 312        .llseek         = no_llseek,
 313        .write          = sc1200wdt_write,
 314        .unlocked_ioctl = sc1200wdt_ioctl,
 315        .open           = sc1200wdt_open,
 316        .release        = sc1200wdt_release,
 317};
 318
 319static struct miscdevice sc1200wdt_miscdev = {
 320        .minor          = WATCHDOG_MINOR,
 321        .name           = "watchdog",
 322        .fops           = &sc1200wdt_fops,
 323};
 324
 325
 326static int __init sc1200wdt_probe(void)
 327{
 328        /* The probe works by reading the PMC3 register's default value of 0x0e
 329         * there is one caveat, if the device disables the parallel port or any
 330         * of the UARTs we won't be able to detect it.
 331         * NB. This could be done with accuracy by reading the SID registers,
 332         * but we don't have access to those io regions.
 333         */
 334
 335        unsigned char reg;
 336
 337        sc1200wdt_read_data(PMC3, &reg);
 338        reg &= 0x0f;            /* we don't want the UART busy bits */
 339        return (reg == 0x0e) ? 0 : -ENODEV;
 340}
 341
 342
 343#if defined CONFIG_PNP
 344
 345static struct pnp_device_id scl200wdt_pnp_devices[] = {
 346        /* National Semiconductor PC87307/PC97307 watchdog component */
 347        {.id = "NSC0800", .driver_data = 0},
 348        {.id = ""},
 349};
 350
 351static int scl200wdt_pnp_probe(struct pnp_dev *dev,
 352                                        const struct pnp_device_id *dev_id)
 353{
 354        /* this driver only supports one card at a time */
 355        if (wdt_dev || !isapnp)
 356                return -EBUSY;
 357
 358        wdt_dev = dev;
 359        io = pnp_port_start(wdt_dev, 0);
 360        io_len = pnp_port_len(wdt_dev, 0);
 361
 362        if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 363                pr_err("Unable to register IO port %#x\n", io);
 364                return -EBUSY;
 365        }
 366
 367        pr_info("PnP device found at io port %#x/%d\n", io, io_len);
 368        return 0;
 369}
 370
 371static void scl200wdt_pnp_remove(struct pnp_dev *dev)
 372{
 373        if (wdt_dev) {
 374                release_region(io, io_len);
 375                wdt_dev = NULL;
 376        }
 377}
 378
 379static struct pnp_driver scl200wdt_pnp_driver = {
 380        .name           = "scl200wdt",
 381        .id_table       = scl200wdt_pnp_devices,
 382        .probe          = scl200wdt_pnp_probe,
 383        .remove         = scl200wdt_pnp_remove,
 384};
 385
 386#endif /* CONFIG_PNP */
 387
 388
 389static int __init sc1200wdt_init(void)
 390{
 391        int ret;
 392
 393        pr_info("%s\n", SC1200_MODULE_VER);
 394
 395#if defined CONFIG_PNP
 396        if (isapnp) {
 397                ret = pnp_register_driver(&scl200wdt_pnp_driver);
 398                if (ret)
 399                        goto out_clean;
 400        }
 401#endif
 402
 403        if (io == -1) {
 404                pr_err("io parameter must be specified\n");
 405                ret = -EINVAL;
 406                goto out_pnp;
 407        }
 408
 409#if defined CONFIG_PNP
 410        /* now that the user has specified an IO port and we haven't detected
 411         * any devices, disable pnp support */
 412        isapnp = 0;
 413        pnp_unregister_driver(&scl200wdt_pnp_driver);
 414#endif
 415
 416        if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 417                pr_err("Unable to register IO port %#x\n", io);
 418                ret = -EBUSY;
 419                goto out_pnp;
 420        }
 421
 422        ret = sc1200wdt_probe();
 423        if (ret)
 424                goto out_io;
 425
 426        ret = register_reboot_notifier(&sc1200wdt_notifier);
 427        if (ret) {
 428                pr_err("Unable to register reboot notifier err = %d\n", ret);
 429                goto out_io;
 430        }
 431
 432        ret = misc_register(&sc1200wdt_miscdev);
 433        if (ret) {
 434                pr_err("Unable to register miscdev on minor %d\n",
 435                       WATCHDOG_MINOR);
 436                goto out_rbt;
 437        }
 438
 439        /* ret = 0 */
 440
 441out_clean:
 442        return ret;
 443
 444out_rbt:
 445        unregister_reboot_notifier(&sc1200wdt_notifier);
 446
 447out_io:
 448        release_region(io, io_len);
 449
 450out_pnp:
 451#if defined CONFIG_PNP
 452        if (isapnp)
 453                pnp_unregister_driver(&scl200wdt_pnp_driver);
 454#endif
 455        goto out_clean;
 456}
 457
 458
 459static void __exit sc1200wdt_exit(void)
 460{
 461        misc_deregister(&sc1200wdt_miscdev);
 462        unregister_reboot_notifier(&sc1200wdt_notifier);
 463
 464#if defined CONFIG_PNP
 465        if (isapnp)
 466                pnp_unregister_driver(&scl200wdt_pnp_driver);
 467        else
 468#endif
 469        release_region(io, io_len);
 470}
 471
 472module_init(sc1200wdt_init);
 473module_exit(sc1200wdt_exit);
 474
 475MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
 476MODULE_DESCRIPTION(
 477        "Driver for National Semiconductor PC87307/PC97307 watchdog component");
 478MODULE_LICENSE("GPL");
 479MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 480
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