linux/drivers/watchdog/sc1200wdt.c
<<
>>
Prefs
   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#include <linux/module.h>
  35#include <linux/moduleparam.h>
  36#include <linux/miscdevice.h>
  37#include <linux/watchdog.h>
  38#include <linux/ioport.h>
  39#include <linux/spinlock.h>
  40#include <linux/notifier.h>
  41#include <linux/reboot.h>
  42#include <linux/init.h>
  43#include <linux/pnp.h>
  44#include <linux/fs.h>
  45#include <linux/semaphore.h>
  46#include <linux/io.h>
  47#include <linux/uaccess.h>
  48
  49#define SC1200_MODULE_VER       "build 20020303"
  50#define SC1200_MODULE_NAME      "sc1200wdt"
  51#define PFX                     SC1200_MODULE_NAME ": "
  52
  53#define MAX_TIMEOUT     255     /* 255 minutes */
  54#define PMIR            (io)    /* Power Management Index Register */
  55#define PMDR            (io+1)  /* Power Management Data Register */
  56
  57/* Data Register indexes */
  58#define FER1            0x00    /* Function enable register 1 */
  59#define FER2            0x01    /* Function enable register 2 */
  60#define PMC1            0x02    /* Power Management Ctrl 1 */
  61#define PMC2            0x03    /* Power Management Ctrl 2 */
  62#define PMC3            0x04    /* Power Management Ctrl 3 */
  63#define WDTO            0x05    /* Watchdog timeout register */
  64#define WDCF            0x06    /* Watchdog config register */
  65#define WDST            0x07    /* Watchdog status register */
  66
  67/* WDCF bitfields - which devices assert WDO */
  68#define KBC_IRQ         0x01    /* Keyboard Controller */
  69#define MSE_IRQ         0x02    /* Mouse */
  70#define UART1_IRQ       0x03    /* Serial0 */
  71#define UART2_IRQ       0x04    /* Serial1 */
  72/* 5 -7 are reserved */
  73
  74static char banner[] __initdata = PFX SC1200_MODULE_VER;
  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 int nowayout = WATCHDOG_NOWAYOUT;
  97module_param(nowayout, int, 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        printk(KERN_INFO PFX "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                printk(KERN_INFO PFX "Watchdog disabled\n");
 258        } else {
 259                sc1200wdt_write_data(WDTO, timeout);
 260                printk(KERN_CRIT PFX
 261                        "Unexpected close!, timeout = %d min(s)\n", timeout);
 262        }
 263        clear_bit(0, &open_flag);
 264        expect_close = 0;
 265
 266        return 0;
 267}
 268
 269
 270static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
 271                                                size_t len, loff_t *ppos)
 272{
 273        if (len) {
 274                if (!nowayout) {
 275                        size_t i;
 276
 277                        expect_close = 0;
 278
 279                        for (i = 0; i != len; i++) {
 280                                char c;
 281
 282                                if (get_user(c, data + i))
 283                                        return -EFAULT;
 284                                if (c == 'V')
 285                                        expect_close = 42;
 286                        }
 287                }
 288
 289                sc1200wdt_write_data(WDTO, timeout);
 290                return len;
 291        }
 292
 293        return 0;
 294}
 295
 296
 297static int sc1200wdt_notify_sys(struct notifier_block *this,
 298                                        unsigned long code, void *unused)
 299{
 300        if (code == SYS_DOWN || code == SYS_HALT)
 301                sc1200wdt_stop();
 302
 303        return NOTIFY_DONE;
 304}
 305
 306
 307static struct notifier_block sc1200wdt_notifier = {
 308        .notifier_call =        sc1200wdt_notify_sys,
 309};
 310
 311static const struct file_operations sc1200wdt_fops = {
 312        .owner          = THIS_MODULE,
 313        .llseek         = no_llseek,
 314        .write          = sc1200wdt_write,
 315        .unlocked_ioctl = sc1200wdt_ioctl,
 316        .open           = sc1200wdt_open,
 317        .release        = sc1200wdt_release,
 318};
 319
 320static struct miscdevice sc1200wdt_miscdev = {
 321        .minor          = WATCHDOG_MINOR,
 322        .name           = "watchdog",
 323        .fops           = &sc1200wdt_fops,
 324};
 325
 326
 327static int __init sc1200wdt_probe(void)
 328{
 329        /* The probe works by reading the PMC3 register's default value of 0x0e
 330         * there is one caveat, if the device disables the parallel port or any
 331         * of the UARTs we won't be able to detect it.
 332         * NB. This could be done with accuracy by reading the SID registers,
 333         * but we don't have access to those io regions.
 334         */
 335
 336        unsigned char reg;
 337
 338        sc1200wdt_read_data(PMC3, &reg);
 339        reg &= 0x0f;            /* we don't want the UART busy bits */
 340        return (reg == 0x0e) ? 0 : -ENODEV;
 341}
 342
 343
 344#if defined CONFIG_PNP
 345
 346static struct pnp_device_id scl200wdt_pnp_devices[] = {
 347        /* National Semiconductor PC87307/PC97307 watchdog component */
 348        {.id = "NSC0800", .driver_data = 0},
 349        {.id = ""},
 350};
 351
 352static int scl200wdt_pnp_probe(struct pnp_dev *dev,
 353                                        const struct pnp_device_id *dev_id)
 354{
 355        /* this driver only supports one card at a time */
 356        if (wdt_dev || !isapnp)
 357                return -EBUSY;
 358
 359        wdt_dev = dev;
 360        io = pnp_port_start(wdt_dev, 0);
 361        io_len = pnp_port_len(wdt_dev, 0);
 362
 363        if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 364                printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
 365                return -EBUSY;
 366        }
 367
 368        printk(KERN_INFO "scl200wdt: PnP device found at io port %#x/%d\n",
 369                                                                io, io_len);
 370        return 0;
 371}
 372
 373static void scl200wdt_pnp_remove(struct pnp_dev *dev)
 374{
 375        if (wdt_dev) {
 376                release_region(io, io_len);
 377                wdt_dev = NULL;
 378        }
 379}
 380
 381static struct pnp_driver scl200wdt_pnp_driver = {
 382        .name           = "scl200wdt",
 383        .id_table       = scl200wdt_pnp_devices,
 384        .probe          = scl200wdt_pnp_probe,
 385        .remove         = scl200wdt_pnp_remove,
 386};
 387
 388#endif /* CONFIG_PNP */
 389
 390
 391static int __init sc1200wdt_init(void)
 392{
 393        int ret;
 394
 395        printk(KERN_INFO "%s\n", banner);
 396
 397#if defined CONFIG_PNP
 398        if (isapnp) {
 399                ret = pnp_register_driver(&scl200wdt_pnp_driver);
 400                if (ret)
 401                        goto out_clean;
 402        }
 403#endif
 404
 405        if (io == -1) {
 406                printk(KERN_ERR PFX "io parameter must be specified\n");
 407                ret = -EINVAL;
 408                goto out_pnp;
 409        }
 410
 411#if defined CONFIG_PNP
 412        /* now that the user has specified an IO port and we haven't detected
 413         * any devices, disable pnp support */
 414        isapnp = 0;
 415        pnp_unregister_driver(&scl200wdt_pnp_driver);
 416#endif
 417
 418        if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
 419                printk(KERN_ERR PFX "Unable to register IO port %#x\n", io);
 420                ret = -EBUSY;
 421                goto out_pnp;
 422        }
 423
 424        ret = sc1200wdt_probe();
 425        if (ret)
 426                goto out_io;
 427
 428        ret = register_reboot_notifier(&sc1200wdt_notifier);
 429        if (ret) {
 430                printk(KERN_ERR PFX
 431                        "Unable to register reboot notifier err = %d\n", ret);
 432                goto out_io;
 433        }
 434
 435        ret = misc_register(&sc1200wdt_miscdev);
 436        if (ret) {
 437                printk(KERN_ERR PFX
 438                        "Unable to register miscdev on minor %d\n",
 439                                                        WATCHDOG_MINOR);
 440                goto out_rbt;
 441        }
 442
 443        /* ret = 0 */
 444
 445out_clean:
 446        return ret;
 447
 448out_rbt:
 449        unregister_reboot_notifier(&sc1200wdt_notifier);
 450
 451out_io:
 452        release_region(io, io_len);
 453
 454out_pnp:
 455#if defined CONFIG_PNP
 456        if (isapnp)
 457                pnp_unregister_driver(&scl200wdt_pnp_driver);
 458#endif
 459        goto out_clean;
 460}
 461
 462
 463static void __exit sc1200wdt_exit(void)
 464{
 465        misc_deregister(&sc1200wdt_miscdev);
 466        unregister_reboot_notifier(&sc1200wdt_notifier);
 467
 468#if defined CONFIG_PNP
 469        if (isapnp)
 470                pnp_unregister_driver(&scl200wdt_pnp_driver);
 471        else
 472#endif
 473        release_region(io, io_len);
 474}
 475
 476module_init(sc1200wdt_init);
 477module_exit(sc1200wdt_exit);
 478
 479MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
 480MODULE_DESCRIPTION(
 481        "Driver for National Semiconductor PC87307/PC97307 watchdog component");
 482MODULE_LICENSE("GPL");
 483MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 484