linux/drivers/watchdog/i6300esb.c
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   1/*
   2 *      i6300esb:       Watchdog timer driver for Intel 6300ESB chipset
   3 *
   4 *      (c) Copyright 2004 Google Inc.
   5 *      (c) Copyright 2005 David Härdeman <david@2gen.com>
   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 *      based on i810-tco.c which is in turn based on softdog.c
  13 *
  14 *      The timer is implemented in the following I/O controller hubs:
  15 *      (See the intel documentation on http://developer.intel.com.)
  16 *      6300ESB chip : document number 300641-004
  17 *
  18 *  2004YYZZ Ross Biro
  19 *      Initial version 0.01
  20 *  2004YYZZ Ross Biro
  21 *      Version 0.02
  22 *  20050210 David Härdeman <david@2gen.com>
  23 *      Ported driver to kernel 2.6
  24 */
  25
  26/*
  27 *      Includes, defines, variables, module parameters, ...
  28 */
  29
  30#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  31
  32#include <linux/module.h>
  33#include <linux/types.h>
  34#include <linux/kernel.h>
  35#include <linux/fs.h>
  36#include <linux/mm.h>
  37#include <linux/miscdevice.h>
  38#include <linux/watchdog.h>
  39#include <linux/init.h>
  40#include <linux/pci.h>
  41#include <linux/ioport.h>
  42#include <linux/uaccess.h>
  43#include <linux/io.h>
  44
  45/* Module and version information */
  46#define ESB_VERSION "0.05"
  47#define ESB_MODULE_NAME "i6300ESB timer"
  48#define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
  49
  50/* PCI configuration registers */
  51#define ESB_CONFIG_REG  0x60            /* Config register                   */
  52#define ESB_LOCK_REG    0x68            /* WDT lock register                 */
  53
  54/* Memory mapped registers */
  55#define ESB_TIMER1_REG (BASEADDR + 0x00)/* Timer1 value after each reset     */
  56#define ESB_TIMER2_REG (BASEADDR + 0x04)/* Timer2 value after each reset     */
  57#define ESB_GINTSR_REG (BASEADDR + 0x08)/* General Interrupt Status Register */
  58#define ESB_RELOAD_REG (BASEADDR + 0x0c)/* Reload register                   */
  59
  60/* Lock register bits */
  61#define ESB_WDT_FUNC    (0x01 << 2)   /* Watchdog functionality            */
  62#define ESB_WDT_ENABLE  (0x01 << 1)   /* Enable WDT                        */
  63#define ESB_WDT_LOCK    (0x01 << 0)   /* Lock (nowayout)                   */
  64
  65/* Config register bits */
  66#define ESB_WDT_REBOOT  (0x01 << 5)   /* Enable reboot on timeout          */
  67#define ESB_WDT_FREQ    (0x01 << 2)   /* Decrement frequency               */
  68#define ESB_WDT_INTTYPE (0x03 << 0)   /* Interrupt type on timer1 timeout  */
  69
  70/* Reload register bits */
  71#define ESB_WDT_TIMEOUT (0x01 << 9)    /* Watchdog timed out                */
  72#define ESB_WDT_RELOAD  (0x01 << 8)    /* prevent timeout                   */
  73
  74/* Magic constants */
  75#define ESB_UNLOCK1     0x80            /* Step 1 to unlock reset registers  */
  76#define ESB_UNLOCK2     0x86            /* Step 2 to unlock reset registers  */
  77
  78/* internal variables */
  79static void __iomem *BASEADDR;
  80static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */
  81static unsigned long timer_alive;
  82static struct pci_dev *esb_pci;
  83static unsigned short triggered; /* The status of the watchdog upon boot */
  84static char esb_expect_close;
  85
  86/* We can only use 1 card due to the /dev/watchdog restriction */
  87static int cards_found;
  88
  89/* module parameters */
  90/* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
  91#define WATCHDOG_HEARTBEAT 30
  92static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  93module_param(heartbeat, int, 0);
  94MODULE_PARM_DESC(heartbeat,
  95                "Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
  96                                __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  97
  98static bool nowayout = WATCHDOG_NOWAYOUT;
  99module_param(nowayout, bool, 0);
 100MODULE_PARM_DESC(nowayout,
 101                "Watchdog cannot be stopped once started (default="
 102                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 103
 104/*
 105 * Some i6300ESB specific functions
 106 */
 107
 108/*
 109 * Prepare for reloading the timer by unlocking the proper registers.
 110 * This is performed by first writing 0x80 followed by 0x86 to the
 111 * reload register. After this the appropriate registers can be written
 112 * to once before they need to be unlocked again.
 113 */
 114static inline void esb_unlock_registers(void)
 115{
 116        writew(ESB_UNLOCK1, ESB_RELOAD_REG);
 117        writew(ESB_UNLOCK2, ESB_RELOAD_REG);
 118}
 119
 120static int esb_timer_start(void)
 121{
 122        u8 val;
 123
 124        spin_lock(&esb_lock);
 125        esb_unlock_registers();
 126        writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 127        /* Enable or Enable + Lock? */
 128        val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
 129        pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
 130        spin_unlock(&esb_lock);
 131        return 0;
 132}
 133
 134static int esb_timer_stop(void)
 135{
 136        u8 val;
 137
 138        spin_lock(&esb_lock);
 139        /* First, reset timers as suggested by the docs */
 140        esb_unlock_registers();
 141        writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 142        /* Then disable the WDT */
 143        pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
 144        pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
 145        spin_unlock(&esb_lock);
 146
 147        /* Returns 0 if the timer was disabled, non-zero otherwise */
 148        return val & ESB_WDT_ENABLE;
 149}
 150
 151static void esb_timer_keepalive(void)
 152{
 153        spin_lock(&esb_lock);
 154        esb_unlock_registers();
 155        writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 156        /* FIXME: Do we need to flush anything here? */
 157        spin_unlock(&esb_lock);
 158}
 159
 160static int esb_timer_set_heartbeat(int time)
 161{
 162        u32 val;
 163
 164        if (time < 0x1 || time > (2 * 0x03ff))
 165                return -EINVAL;
 166
 167        spin_lock(&esb_lock);
 168
 169        /* We shift by 9, so if we are passed a value of 1 sec,
 170         * val will be 1 << 9 = 512, then write that to two
 171         * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
 172         */
 173        val = time << 9;
 174
 175        /* Write timer 1 */
 176        esb_unlock_registers();
 177        writel(val, ESB_TIMER1_REG);
 178
 179        /* Write timer 2 */
 180        esb_unlock_registers();
 181        writel(val, ESB_TIMER2_REG);
 182
 183        /* Reload */
 184        esb_unlock_registers();
 185        writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 186
 187        /* FIXME: Do we need to flush everything out? */
 188
 189        /* Done */
 190        heartbeat = time;
 191        spin_unlock(&esb_lock);
 192        return 0;
 193}
 194
 195/*
 196 *      /dev/watchdog handling
 197 */
 198
 199static int esb_open(struct inode *inode, struct file *file)
 200{
 201        /* /dev/watchdog can only be opened once */
 202        if (test_and_set_bit(0, &timer_alive))
 203                return -EBUSY;
 204
 205        /* Reload and activate timer */
 206        esb_timer_start();
 207
 208        return nonseekable_open(inode, file);
 209}
 210
 211static int esb_release(struct inode *inode, struct file *file)
 212{
 213        /* Shut off the timer. */
 214        if (esb_expect_close == 42)
 215                esb_timer_stop();
 216        else {
 217                pr_crit("Unexpected close, not stopping watchdog!\n");
 218                esb_timer_keepalive();
 219        }
 220        clear_bit(0, &timer_alive);
 221        esb_expect_close = 0;
 222        return 0;
 223}
 224
 225static ssize_t esb_write(struct file *file, const char __user *data,
 226                          size_t len, loff_t *ppos)
 227{
 228        /* See if we got the magic character 'V' and reload the timer */
 229        if (len) {
 230                if (!nowayout) {
 231                        size_t i;
 232
 233                        /* note: just in case someone wrote the magic character
 234                         * five months ago... */
 235                        esb_expect_close = 0;
 236
 237                        /* scan to see whether or not we got the
 238                         * magic character */
 239                        for (i = 0; i != len; i++) {
 240                                char c;
 241                                if (get_user(c, data + i))
 242                                        return -EFAULT;
 243                                if (c == 'V')
 244                                        esb_expect_close = 42;
 245                        }
 246                }
 247
 248                /* someone wrote to us, we should reload the timer */
 249                esb_timer_keepalive();
 250        }
 251        return len;
 252}
 253
 254static long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 255{
 256        int new_options, retval = -EINVAL;
 257        int new_heartbeat;
 258        void __user *argp = (void __user *)arg;
 259        int __user *p = argp;
 260        static const struct watchdog_info ident = {
 261                .options =              WDIOF_SETTIMEOUT |
 262                                        WDIOF_KEEPALIVEPING |
 263                                        WDIOF_MAGICCLOSE,
 264                .firmware_version =     0,
 265                .identity =             ESB_MODULE_NAME,
 266        };
 267
 268        switch (cmd) {
 269        case WDIOC_GETSUPPORT:
 270                return copy_to_user(argp, &ident,
 271                                        sizeof(ident)) ? -EFAULT : 0;
 272
 273        case WDIOC_GETSTATUS:
 274                return put_user(0, p);
 275
 276        case WDIOC_GETBOOTSTATUS:
 277                return put_user(triggered, p);
 278
 279        case WDIOC_SETOPTIONS:
 280        {
 281                if (get_user(new_options, p))
 282                        return -EFAULT;
 283
 284                if (new_options & WDIOS_DISABLECARD) {
 285                        esb_timer_stop();
 286                        retval = 0;
 287                }
 288
 289                if (new_options & WDIOS_ENABLECARD) {
 290                        esb_timer_start();
 291                        retval = 0;
 292                }
 293                return retval;
 294        }
 295        case WDIOC_KEEPALIVE:
 296                esb_timer_keepalive();
 297                return 0;
 298
 299        case WDIOC_SETTIMEOUT:
 300        {
 301                if (get_user(new_heartbeat, p))
 302                        return -EFAULT;
 303                if (esb_timer_set_heartbeat(new_heartbeat))
 304                        return -EINVAL;
 305                esb_timer_keepalive();
 306                /* Fall */
 307        }
 308        case WDIOC_GETTIMEOUT:
 309                return put_user(heartbeat, p);
 310        default:
 311                return -ENOTTY;
 312        }
 313}
 314
 315/*
 316 *      Kernel Interfaces
 317 */
 318
 319static const struct file_operations esb_fops = {
 320        .owner = THIS_MODULE,
 321        .llseek = no_llseek,
 322        .write = esb_write,
 323        .unlocked_ioctl = esb_ioctl,
 324        .open = esb_open,
 325        .release = esb_release,
 326};
 327
 328static struct miscdevice esb_miscdev = {
 329        .minor = WATCHDOG_MINOR,
 330        .name = "watchdog",
 331        .fops = &esb_fops,
 332};
 333
 334/*
 335 * Data for PCI driver interface
 336 */
 337static DEFINE_PCI_DEVICE_TABLE(esb_pci_tbl) = {
 338        { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
 339        { 0, },                 /* End of list */
 340};
 341MODULE_DEVICE_TABLE(pci, esb_pci_tbl);
 342
 343/*
 344 *      Init & exit routines
 345 */
 346
 347static unsigned char esb_getdevice(struct pci_dev *pdev)
 348{
 349        if (pci_enable_device(pdev)) {
 350                pr_err("failed to enable device\n");
 351                goto err_devput;
 352        }
 353
 354        if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
 355                pr_err("failed to request region\n");
 356                goto err_disable;
 357        }
 358
 359        BASEADDR = pci_ioremap_bar(pdev, 0);
 360        if (BASEADDR == NULL) {
 361                /* Something's wrong here, BASEADDR has to be set */
 362                pr_err("failed to get BASEADDR\n");
 363                goto err_release;
 364        }
 365
 366        /* Done */
 367        esb_pci = pdev;
 368        return 1;
 369
 370err_release:
 371        pci_release_region(pdev, 0);
 372err_disable:
 373        pci_disable_device(pdev);
 374err_devput:
 375        return 0;
 376}
 377
 378static void esb_initdevice(void)
 379{
 380        u8 val1;
 381        u16 val2;
 382
 383        /*
 384         * Config register:
 385         * Bit    5 : 0 = Enable WDT_OUTPUT
 386         * Bit    2 : 0 = set the timer frequency to the PCI clock
 387         * divided by 2^15 (approx 1KHz).
 388         * Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
 389         * The watchdog has two timers, it can be setup so that the
 390         * expiry of timer1 results in an interrupt and the expiry of
 391         * timer2 results in a reboot. We set it to not generate
 392         * any interrupts as there is not much we can do with it
 393         * right now.
 394         */
 395        pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
 396
 397        /* Check that the WDT isn't already locked */
 398        pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
 399        if (val1 & ESB_WDT_LOCK)
 400                pr_warn("nowayout already set\n");
 401
 402        /* Set the timer to watchdog mode and disable it for now */
 403        pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
 404
 405        /* Check if the watchdog was previously triggered */
 406        esb_unlock_registers();
 407        val2 = readw(ESB_RELOAD_REG);
 408        if (val2 & ESB_WDT_TIMEOUT)
 409                triggered = WDIOF_CARDRESET;
 410
 411        /* Reset WDT_TIMEOUT flag and timers */
 412        esb_unlock_registers();
 413        writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);
 414
 415        /* And set the correct timeout value */
 416        esb_timer_set_heartbeat(heartbeat);
 417}
 418
 419static int esb_probe(struct pci_dev *pdev,
 420                const struct pci_device_id *ent)
 421{
 422        int ret;
 423
 424        cards_found++;
 425        if (cards_found == 1)
 426                pr_info("Intel 6300ESB WatchDog Timer Driver v%s\n",
 427                        ESB_VERSION);
 428
 429        if (cards_found > 1) {
 430                pr_err("This driver only supports 1 device\n");
 431                return -ENODEV;
 432        }
 433
 434        /* Check whether or not the hardware watchdog is there */
 435        if (!esb_getdevice(pdev) || esb_pci == NULL)
 436                return -ENODEV;
 437
 438        /* Check that the heartbeat value is within it's range;
 439           if not reset to the default */
 440        if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
 441                heartbeat = WATCHDOG_HEARTBEAT;
 442                pr_info("heartbeat value must be 1<heartbeat<2046, using %d\n",
 443                        heartbeat);
 444        }
 445
 446        /* Initialize the watchdog and make sure it does not run */
 447        esb_initdevice();
 448
 449        /* Register the watchdog so that userspace has access to it */
 450        ret = misc_register(&esb_miscdev);
 451        if (ret != 0) {
 452                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 453                       WATCHDOG_MINOR, ret);
 454                goto err_unmap;
 455        }
 456        pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
 457                BASEADDR, heartbeat, nowayout);
 458        return 0;
 459
 460err_unmap:
 461        iounmap(BASEADDR);
 462        pci_release_region(esb_pci, 0);
 463        pci_disable_device(esb_pci);
 464        esb_pci = NULL;
 465        return ret;
 466}
 467
 468static void esb_remove(struct pci_dev *pdev)
 469{
 470        /* Stop the timer before we leave */
 471        if (!nowayout)
 472                esb_timer_stop();
 473
 474        /* Deregister */
 475        misc_deregister(&esb_miscdev);
 476        iounmap(BASEADDR);
 477        pci_release_region(esb_pci, 0);
 478        pci_disable_device(esb_pci);
 479        esb_pci = NULL;
 480}
 481
 482static void esb_shutdown(struct pci_dev *pdev)
 483{
 484        esb_timer_stop();
 485}
 486
 487static struct pci_driver esb_driver = {
 488        .name           = ESB_MODULE_NAME,
 489        .id_table       = esb_pci_tbl,
 490        .probe          = esb_probe,
 491        .remove         = esb_remove,
 492        .shutdown       = esb_shutdown,
 493};
 494
 495module_pci_driver(esb_driver);
 496
 497MODULE_AUTHOR("Ross Biro and David Härdeman");
 498MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
 499MODULE_LICENSE("GPL");
 500MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 501
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