linux/drivers/watchdog/nv_tco.c
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   1/*
   2 *      nv_tco 0.01:    TCO timer driver for NV chipsets
   3 *
   4 *      (c) Copyright 2005 Google Inc., All Rights Reserved.
   5 *
   6 *      Based off i8xx_tco.c:
   7 *      (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
   8 *      Reserved.
   9 *                              http://www.kernelconcepts.de
  10 *
  11 *      This program is free software; you can redistribute it and/or
  12 *      modify it under the terms of the GNU General Public License
  13 *      as published by the Free Software Foundation; either version
  14 *      2 of the License, or (at your option) any later version.
  15 *
  16 *      TCO timer driver for NV chipsets
  17 *      based on softdog.c by Alan Cox <alan@redhat.com>
  18 */
  19
  20/*
  21 *      Includes, defines, variables, module parameters, ...
  22 */
  23
  24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  25
  26#include <linux/module.h>
  27#include <linux/moduleparam.h>
  28#include <linux/types.h>
  29#include <linux/miscdevice.h>
  30#include <linux/watchdog.h>
  31#include <linux/init.h>
  32#include <linux/fs.h>
  33#include <linux/pci.h>
  34#include <linux/ioport.h>
  35#include <linux/jiffies.h>
  36#include <linux/platform_device.h>
  37#include <linux/uaccess.h>
  38#include <linux/io.h>
  39
  40#include "nv_tco.h"
  41
  42/* Module and version information */
  43#define TCO_VERSION "0.01"
  44#define TCO_MODULE_NAME "NV_TCO"
  45#define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
  46
  47/* internal variables */
  48static unsigned int tcobase;
  49static DEFINE_SPINLOCK(tco_lock);       /* Guards the hardware */
  50static unsigned long timer_alive;
  51static char tco_expect_close;
  52static struct pci_dev *tco_pci;
  53
  54/* the watchdog platform device */
  55static struct platform_device *nv_tco_platform_device;
  56
  57/* module parameters */
  58#define WATCHDOG_HEARTBEAT 30   /* 30 sec default heartbeat (2<heartbeat<39) */
  59static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  60module_param(heartbeat, int, 0);
  61MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
  62                            "default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  63
  64static bool nowayout = WATCHDOG_NOWAYOUT;
  65module_param(nowayout, bool, 0);
  66MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
  67                " (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  68
  69/*
  70 * Some TCO specific functions
  71 */
  72static inline unsigned char seconds_to_ticks(int seconds)
  73{
  74        /* the internal timer is stored as ticks which decrement
  75         * every 0.6 seconds */
  76        return (seconds * 10) / 6;
  77}
  78
  79static void tco_timer_start(void)
  80{
  81        u32 val;
  82        unsigned long flags;
  83
  84        spin_lock_irqsave(&tco_lock, flags);
  85        val = inl(TCO_CNT(tcobase));
  86        val &= ~TCO_CNT_TCOHALT;
  87        outl(val, TCO_CNT(tcobase));
  88        spin_unlock_irqrestore(&tco_lock, flags);
  89}
  90
  91static void tco_timer_stop(void)
  92{
  93        u32 val;
  94        unsigned long flags;
  95
  96        spin_lock_irqsave(&tco_lock, flags);
  97        val = inl(TCO_CNT(tcobase));
  98        val |= TCO_CNT_TCOHALT;
  99        outl(val, TCO_CNT(tcobase));
 100        spin_unlock_irqrestore(&tco_lock, flags);
 101}
 102
 103static void tco_timer_keepalive(void)
 104{
 105        unsigned long flags;
 106
 107        spin_lock_irqsave(&tco_lock, flags);
 108        outb(0x01, TCO_RLD(tcobase));
 109        spin_unlock_irqrestore(&tco_lock, flags);
 110}
 111
 112static int tco_timer_set_heartbeat(int t)
 113{
 114        int ret = 0;
 115        unsigned char tmrval;
 116        unsigned long flags;
 117        u8 val;
 118
 119        /*
 120         * note seconds_to_ticks(t) > t, so if t > 0x3f, so is
 121         * tmrval=seconds_to_ticks(t).  Check that the count in seconds isn't
 122         * out of range on it's own (to avoid overflow in tmrval).
 123         */
 124        if (t < 0 || t > 0x3f)
 125                return -EINVAL;
 126        tmrval = seconds_to_ticks(t);
 127
 128        /* "Values of 0h-3h are ignored and should not be attempted" */
 129        if (tmrval > 0x3f || tmrval < 0x04)
 130                return -EINVAL;
 131
 132        /* Write new heartbeat to watchdog */
 133        spin_lock_irqsave(&tco_lock, flags);
 134        val = inb(TCO_TMR(tcobase));
 135        val &= 0xc0;
 136        val |= tmrval;
 137        outb(val, TCO_TMR(tcobase));
 138        val = inb(TCO_TMR(tcobase));
 139
 140        if ((val & 0x3f) != tmrval)
 141                ret = -EINVAL;
 142        spin_unlock_irqrestore(&tco_lock, flags);
 143
 144        if (ret)
 145                return ret;
 146
 147        heartbeat = t;
 148        return 0;
 149}
 150
 151/*
 152 *      /dev/watchdog handling
 153 */
 154
 155static int nv_tco_open(struct inode *inode, struct file *file)
 156{
 157        /* /dev/watchdog can only be opened once */
 158        if (test_and_set_bit(0, &timer_alive))
 159                return -EBUSY;
 160
 161        /* Reload and activate timer */
 162        tco_timer_keepalive();
 163        tco_timer_start();
 164        return nonseekable_open(inode, file);
 165}
 166
 167static int nv_tco_release(struct inode *inode, struct file *file)
 168{
 169        /* Shut off the timer */
 170        if (tco_expect_close == 42) {
 171                tco_timer_stop();
 172        } else {
 173                pr_crit("Unexpected close, not stopping watchdog!\n");
 174                tco_timer_keepalive();
 175        }
 176        clear_bit(0, &timer_alive);
 177        tco_expect_close = 0;
 178        return 0;
 179}
 180
 181static ssize_t nv_tco_write(struct file *file, const char __user *data,
 182                            size_t len, loff_t *ppos)
 183{
 184        /* See if we got the magic character 'V' and reload the timer */
 185        if (len) {
 186                if (!nowayout) {
 187                        size_t i;
 188
 189                        /*
 190                         * note: just in case someone wrote the magic character
 191                         * five months ago...
 192                         */
 193                        tco_expect_close = 0;
 194
 195                        /*
 196                         * scan to see whether or not we got the magic
 197                         * character
 198                         */
 199                        for (i = 0; i != len; i++) {
 200                                char c;
 201                                if (get_user(c, data + i))
 202                                        return -EFAULT;
 203                                if (c == 'V')
 204                                        tco_expect_close = 42;
 205                        }
 206                }
 207
 208                /* someone wrote to us, we should reload the timer */
 209                tco_timer_keepalive();
 210        }
 211        return len;
 212}
 213
 214static long nv_tco_ioctl(struct file *file, unsigned int cmd,
 215                         unsigned long arg)
 216{
 217        int new_options, retval = -EINVAL;
 218        int new_heartbeat;
 219        void __user *argp = (void __user *)arg;
 220        int __user *p = argp;
 221        static const struct watchdog_info ident = {
 222                .options =              WDIOF_SETTIMEOUT |
 223                                        WDIOF_KEEPALIVEPING |
 224                                        WDIOF_MAGICCLOSE,
 225                .firmware_version =     0,
 226                .identity =             TCO_MODULE_NAME,
 227        };
 228
 229        switch (cmd) {
 230        case WDIOC_GETSUPPORT:
 231                return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 232        case WDIOC_GETSTATUS:
 233        case WDIOC_GETBOOTSTATUS:
 234                return put_user(0, p);
 235        case WDIOC_SETOPTIONS:
 236                if (get_user(new_options, p))
 237                        return -EFAULT;
 238                if (new_options & WDIOS_DISABLECARD) {
 239                        tco_timer_stop();
 240                        retval = 0;
 241                }
 242                if (new_options & WDIOS_ENABLECARD) {
 243                        tco_timer_keepalive();
 244                        tco_timer_start();
 245                        retval = 0;
 246                }
 247                return retval;
 248        case WDIOC_KEEPALIVE:
 249                tco_timer_keepalive();
 250                return 0;
 251        case WDIOC_SETTIMEOUT:
 252                if (get_user(new_heartbeat, p))
 253                        return -EFAULT;
 254                if (tco_timer_set_heartbeat(new_heartbeat))
 255                        return -EINVAL;
 256                tco_timer_keepalive();
 257                /* Fall through */
 258        case WDIOC_GETTIMEOUT:
 259                return put_user(heartbeat, p);
 260        default:
 261                return -ENOTTY;
 262        }
 263}
 264
 265/*
 266 *      Kernel Interfaces
 267 */
 268
 269static const struct file_operations nv_tco_fops = {
 270        .owner =                THIS_MODULE,
 271        .llseek =               no_llseek,
 272        .write =                nv_tco_write,
 273        .unlocked_ioctl =       nv_tco_ioctl,
 274        .open =                 nv_tco_open,
 275        .release =              nv_tco_release,
 276};
 277
 278static struct miscdevice nv_tco_miscdev = {
 279        .minor =        WATCHDOG_MINOR,
 280        .name =         "watchdog",
 281        .fops =         &nv_tco_fops,
 282};
 283
 284/*
 285 * Data for PCI driver interface
 286 *
 287 * This data only exists for exporting the supported
 288 * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 289 * register a pci_driver, because someone else might one day
 290 * want to register another driver on the same PCI id.
 291 */
 292static DEFINE_PCI_DEVICE_TABLE(tco_pci_tbl) = {
 293        { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS,
 294          PCI_ANY_ID, PCI_ANY_ID, },
 295        { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS,
 296          PCI_ANY_ID, PCI_ANY_ID, },
 297        { 0, },                 /* End of list */
 298};
 299MODULE_DEVICE_TABLE(pci, tco_pci_tbl);
 300
 301/*
 302 *      Init & exit routines
 303 */
 304
 305static unsigned char __devinit nv_tco_getdevice(void)
 306{
 307        struct pci_dev *dev = NULL;
 308        u32 val;
 309
 310        /* Find the PCI device */
 311        for_each_pci_dev(dev) {
 312                if (pci_match_id(tco_pci_tbl, dev) != NULL) {
 313                        tco_pci = dev;
 314                        break;
 315                }
 316        }
 317
 318        if (!tco_pci)
 319                return 0;
 320
 321        /* Find the base io port */
 322        pci_read_config_dword(tco_pci, 0x64, &val);
 323        val &= 0xffff;
 324        if (val == 0x0001 || val == 0x0000) {
 325                /* Something is wrong here, bar isn't setup */
 326                pr_err("failed to get tcobase address\n");
 327                return 0;
 328        }
 329        val &= 0xff00;
 330        tcobase = val + 0x40;
 331
 332        if (!request_region(tcobase, 0x10, "NV TCO")) {
 333                pr_err("I/O address 0x%04x already in use\n", tcobase);
 334                return 0;
 335        }
 336
 337        /* Set a reasonable heartbeat before we stop the timer */
 338        tco_timer_set_heartbeat(30);
 339
 340        /*
 341         * Stop the TCO before we change anything so we don't race with
 342         * a zeroed timer.
 343         */
 344        tco_timer_keepalive();
 345        tco_timer_stop();
 346
 347        /* Disable SMI caused by TCO */
 348        if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) {
 349                pr_err("I/O address 0x%04x already in use\n",
 350                       MCP51_SMI_EN(tcobase));
 351                goto out;
 352        }
 353        val = inl(MCP51_SMI_EN(tcobase));
 354        val &= ~MCP51_SMI_EN_TCO;
 355        outl(val, MCP51_SMI_EN(tcobase));
 356        val = inl(MCP51_SMI_EN(tcobase));
 357        release_region(MCP51_SMI_EN(tcobase), 4);
 358        if (val & MCP51_SMI_EN_TCO) {
 359                pr_err("Could not disable SMI caused by TCO\n");
 360                goto out;
 361        }
 362
 363        /* Check chipset's NO_REBOOT bit */
 364        pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 365        val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT;
 366        pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
 367        pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 368        if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) {
 369                pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n");
 370                goto out;
 371        }
 372
 373        return 1;
 374out:
 375        release_region(tcobase, 0x10);
 376        return 0;
 377}
 378
 379static int __devinit nv_tco_init(struct platform_device *dev)
 380{
 381        int ret;
 382
 383        /* Check whether or not the hardware watchdog is there */
 384        if (!nv_tco_getdevice())
 385                return -ENODEV;
 386
 387        /* Check to see if last reboot was due to watchdog timeout */
 388        pr_info("Watchdog reboot %sdetected\n",
 389                inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not ");
 390
 391        /* Clear out the old status */
 392        outl(TCO_STS_RESET, TCO_STS(tcobase));
 393
 394        /*
 395         * Check that the heartbeat value is within it's range.
 396         * If not, reset to the default.
 397         */
 398        if (tco_timer_set_heartbeat(heartbeat)) {
 399                heartbeat = WATCHDOG_HEARTBEAT;
 400                tco_timer_set_heartbeat(heartbeat);
 401                pr_info("heartbeat value must be 2<heartbeat<39, using %d\n",
 402                        heartbeat);
 403        }
 404
 405        ret = misc_register(&nv_tco_miscdev);
 406        if (ret != 0) {
 407                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 408                       WATCHDOG_MINOR, ret);
 409                goto unreg_region;
 410        }
 411
 412        clear_bit(0, &timer_alive);
 413
 414        tco_timer_stop();
 415
 416        pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n",
 417                tcobase, heartbeat, nowayout);
 418
 419        return 0;
 420
 421unreg_region:
 422        release_region(tcobase, 0x10);
 423        return ret;
 424}
 425
 426static void __devexit nv_tco_cleanup(void)
 427{
 428        u32 val;
 429
 430        /* Stop the timer before we leave */
 431        if (!nowayout)
 432                tco_timer_stop();
 433
 434        /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
 435        pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 436        val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
 437        pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
 438        pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 439        if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) {
 440                pr_crit("Couldn't unset REBOOT bit.  Machine may soon reset\n");
 441        }
 442
 443        /* Deregister */
 444        misc_deregister(&nv_tco_miscdev);
 445        release_region(tcobase, 0x10);
 446}
 447
 448static int __devexit nv_tco_remove(struct platform_device *dev)
 449{
 450        if (tcobase)
 451                nv_tco_cleanup();
 452
 453        return 0;
 454}
 455
 456static void nv_tco_shutdown(struct platform_device *dev)
 457{
 458        u32 val;
 459
 460        tco_timer_stop();
 461
 462        /* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not
 463         * unset during shutdown. */
 464        pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
 465        val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
 466        pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
 467}
 468
 469static struct platform_driver nv_tco_driver = {
 470        .probe          = nv_tco_init,
 471        .remove         = __devexit_p(nv_tco_remove),
 472        .shutdown       = nv_tco_shutdown,
 473        .driver         = {
 474                .owner  = THIS_MODULE,
 475                .name   = TCO_MODULE_NAME,
 476        },
 477};
 478
 479static int __init nv_tco_init_module(void)
 480{
 481        int err;
 482
 483        pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION);
 484
 485        err = platform_driver_register(&nv_tco_driver);
 486        if (err)
 487                return err;
 488
 489        nv_tco_platform_device = platform_device_register_simple(
 490                                        TCO_MODULE_NAME, -1, NULL, 0);
 491        if (IS_ERR(nv_tco_platform_device)) {
 492                err = PTR_ERR(nv_tco_platform_device);
 493                goto unreg_platform_driver;
 494        }
 495
 496        return 0;
 497
 498unreg_platform_driver:
 499        platform_driver_unregister(&nv_tco_driver);
 500        return err;
 501}
 502
 503static void __exit nv_tco_cleanup_module(void)
 504{
 505        platform_device_unregister(nv_tco_platform_device);
 506        platform_driver_unregister(&nv_tco_driver);
 507        pr_info("NV TCO Watchdog Module Unloaded\n");
 508}
 509
 510module_init(nv_tco_init_module);
 511module_exit(nv_tco_cleanup_module);
 512
 513MODULE_AUTHOR("Mike Waychison");
 514MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
 515MODULE_LICENSE("GPL");
 516MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 517
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