linux/drivers/watchdog/alim7101_wdt.c
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   1/*
   2 *      ALi M7101 PMU Computer Watchdog Timer driver
   3 *
   4 *      Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net>
   5 *      and the Cobalt kernel WDT timer driver by Tim Hockin
   6 *                                            <thockin@cobaltnet.com>
   7 *
   8 *      (c)2002 Steve Hill <steve@navaho.co.uk>
   9 *
  10 *  This WDT driver is different from most other Linux WDT
  11 *  drivers in that the driver will ping the watchdog by itself,
  12 *  because this particular WDT has a very short timeout (1.6
  13 *  seconds) and it would be insane to count on any userspace
  14 *  daemon always getting scheduled within that time frame.
  15 *
  16 *  Additions:
  17 *   Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs
  18 *                  found on very old cobalt hardware.
  19 *                  -- Mike Waychison <michael.waychison@sun.com>
  20 */
  21
  22#include <linux/module.h>
  23#include <linux/moduleparam.h>
  24#include <linux/types.h>
  25#include <linux/timer.h>
  26#include <linux/miscdevice.h>
  27#include <linux/watchdog.h>
  28#include <linux/ioport.h>
  29#include <linux/notifier.h>
  30#include <linux/reboot.h>
  31#include <linux/init.h>
  32#include <linux/fs.h>
  33#include <linux/pci.h>
  34#include <linux/io.h>
  35#include <linux/uaccess.h>
  36
  37#include <asm/system.h>
  38
  39#define OUR_NAME "alim7101_wdt"
  40#define PFX OUR_NAME ": "
  41
  42#define WDT_ENABLE 0x9C
  43#define WDT_DISABLE 0x8C
  44
  45#define ALI_7101_WDT    0x92
  46#define ALI_7101_GPIO   0x7D
  47#define ALI_7101_GPIO_O 0x7E
  48#define ALI_WDT_ARM     0x01
  49
  50/*
  51 * We're going to use a 1 second timeout.
  52 * If we reset the watchdog every ~250ms we should be safe.  */
  53
  54#define WDT_INTERVAL (HZ/4+1)
  55
  56/*
  57 * We must not require too good response from the userspace daemon.
  58 * Here we require the userspace daemon to send us a heartbeat
  59 * char to /dev/watchdog every 30 seconds.
  60 */
  61
  62#define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */
  63/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
  64static int timeout = WATCHDOG_TIMEOUT;
  65module_param(timeout, int, 0);
  66MODULE_PARM_DESC(timeout,
  67                "Watchdog timeout in seconds. (1<=timeout<=3600, default="
  68                                __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
  69
  70static int use_gpio; /* Use the pic (for a1d revision alim7101) */
  71module_param(use_gpio, int, 0);
  72MODULE_PARM_DESC(use_gpio,
  73                "Use the gpio watchdog (required by old cobalt boards).");
  74
  75static void wdt_timer_ping(unsigned long);
  76static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
  77static unsigned long next_heartbeat;
  78static unsigned long wdt_is_open;
  79static char wdt_expect_close;
  80static struct pci_dev *alim7101_pmu;
  81
  82static int nowayout = WATCHDOG_NOWAYOUT;
  83module_param(nowayout, int, 0);
  84MODULE_PARM_DESC(nowayout,
  85                "Watchdog cannot be stopped once started (default="
  86                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  87
  88/*
  89 *      Whack the dog
  90 */
  91
  92static void wdt_timer_ping(unsigned long data)
  93{
  94        /* If we got a heartbeat pulse within the WDT_US_INTERVAL
  95         * we agree to ping the WDT
  96         */
  97        char tmp;
  98
  99        if (time_before(jiffies, next_heartbeat)) {
 100                /* Ping the WDT (this is actually a disarm/arm sequence) */
 101                pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
 102                pci_write_config_byte(alim7101_pmu,
 103                                        ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
 104                pci_write_config_byte(alim7101_pmu,
 105                                        ALI_7101_WDT, (tmp | ALI_WDT_ARM));
 106                if (use_gpio) {
 107                        pci_read_config_byte(alim7101_pmu,
 108                                        ALI_7101_GPIO_O, &tmp);
 109                        pci_write_config_byte(alim7101_pmu,
 110                                        ALI_7101_GPIO_O, tmp | 0x20);
 111                        pci_write_config_byte(alim7101_pmu,
 112                                        ALI_7101_GPIO_O, tmp & ~0x20);
 113                }
 114        } else {
 115                printk(KERN_WARNING PFX
 116                        "Heartbeat lost! Will not ping the watchdog\n");
 117        }
 118        /* Re-set the timer interval */
 119        mod_timer(&timer, jiffies + WDT_INTERVAL);
 120}
 121
 122/*
 123 * Utility routines
 124 */
 125
 126static void wdt_change(int writeval)
 127{
 128        char tmp;
 129
 130        pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
 131        if (writeval == WDT_ENABLE) {
 132                pci_write_config_byte(alim7101_pmu,
 133                                        ALI_7101_WDT, (tmp | ALI_WDT_ARM));
 134                if (use_gpio) {
 135                        pci_read_config_byte(alim7101_pmu,
 136                                        ALI_7101_GPIO_O, &tmp);
 137                        pci_write_config_byte(alim7101_pmu,
 138                                        ALI_7101_GPIO_O, tmp & ~0x20);
 139                }
 140
 141        } else {
 142                pci_write_config_byte(alim7101_pmu,
 143                                        ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
 144                if (use_gpio) {
 145                        pci_read_config_byte(alim7101_pmu,
 146                                        ALI_7101_GPIO_O, &tmp);
 147                        pci_write_config_byte(alim7101_pmu,
 148                                        ALI_7101_GPIO_O, tmp | 0x20);
 149                }
 150        }
 151}
 152
 153static void wdt_startup(void)
 154{
 155        next_heartbeat = jiffies + (timeout * HZ);
 156
 157        /* We must enable before we kick off the timer in case the timer
 158           occurs as we ping it */
 159
 160        wdt_change(WDT_ENABLE);
 161
 162        /* Start the timer */
 163        mod_timer(&timer, jiffies + WDT_INTERVAL);
 164
 165        printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
 166}
 167
 168static void wdt_turnoff(void)
 169{
 170        /* Stop the timer */
 171        del_timer_sync(&timer);
 172        wdt_change(WDT_DISABLE);
 173        printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
 174}
 175
 176static void wdt_keepalive(void)
 177{
 178        /* user land ping */
 179        next_heartbeat = jiffies + (timeout * HZ);
 180}
 181
 182/*
 183 * /dev/watchdog handling
 184 */
 185
 186static ssize_t fop_write(struct file *file, const char __user *buf,
 187                                                size_t count, loff_t *ppos)
 188{
 189        /* See if we got the magic character 'V' and reload the timer */
 190        if (count) {
 191                if (!nowayout) {
 192                        size_t ofs;
 193
 194                        /* note: just in case someone wrote the magic character
 195                         * five months ago... */
 196                        wdt_expect_close = 0;
 197
 198                        /* now scan */
 199                        for (ofs = 0; ofs != count; ofs++) {
 200                                char c;
 201                                if (get_user(c, buf + ofs))
 202                                        return -EFAULT;
 203                                if (c == 'V')
 204                                        wdt_expect_close = 42;
 205                        }
 206                }
 207                /* someone wrote to us, we should restart timer */
 208                wdt_keepalive();
 209        }
 210        return count;
 211}
 212
 213static int fop_open(struct inode *inode, struct file *file)
 214{
 215        /* Just in case we're already talking to someone... */
 216        if (test_and_set_bit(0, &wdt_is_open))
 217                return -EBUSY;
 218        /* Good, fire up the show */
 219        wdt_startup();
 220        return nonseekable_open(inode, file);
 221}
 222
 223static int fop_close(struct inode *inode, struct file *file)
 224{
 225        if (wdt_expect_close == 42)
 226                wdt_turnoff();
 227        else {
 228                /* wim: shouldn't there be a: del_timer(&timer); */
 229                printk(KERN_CRIT PFX
 230                  "device file closed unexpectedly. Will not stop the WDT!\n");
 231        }
 232        clear_bit(0, &wdt_is_open);
 233        wdt_expect_close = 0;
 234        return 0;
 235}
 236
 237static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 238{
 239        void __user *argp = (void __user *)arg;
 240        int __user *p = argp;
 241        static struct watchdog_info ident = {
 242                .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
 243                                                        | WDIOF_MAGICCLOSE,
 244                .firmware_version = 1,
 245                .identity = "ALiM7101",
 246        };
 247
 248        switch (cmd) {
 249        case WDIOC_GETSUPPORT:
 250                return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 251        case WDIOC_GETSTATUS:
 252        case WDIOC_GETBOOTSTATUS:
 253                return put_user(0, p);
 254        case WDIOC_SETOPTIONS:
 255        {
 256                int new_options, retval = -EINVAL;
 257
 258                if (get_user(new_options, p))
 259                        return -EFAULT;
 260                if (new_options & WDIOS_DISABLECARD) {
 261                        wdt_turnoff();
 262                        retval = 0;
 263                }
 264                if (new_options & WDIOS_ENABLECARD) {
 265                        wdt_startup();
 266                        retval = 0;
 267                }
 268                return retval;
 269        }
 270        case WDIOC_KEEPALIVE:
 271                wdt_keepalive();
 272                return 0;
 273        case WDIOC_SETTIMEOUT:
 274        {
 275                int new_timeout;
 276
 277                if (get_user(new_timeout, p))
 278                        return -EFAULT;
 279                /* arbitrary upper limit */
 280                if (new_timeout < 1 || new_timeout > 3600)
 281                        return -EINVAL;
 282                timeout = new_timeout;
 283                wdt_keepalive();
 284                /* Fall through */
 285        }
 286        case WDIOC_GETTIMEOUT:
 287                return put_user(timeout, p);
 288        default:
 289                return -ENOTTY;
 290        }
 291}
 292
 293static const struct file_operations wdt_fops = {
 294        .owner          =       THIS_MODULE,
 295        .llseek         =       no_llseek,
 296        .write          =       fop_write,
 297        .open           =       fop_open,
 298        .release        =       fop_close,
 299        .unlocked_ioctl =       fop_ioctl,
 300};
 301
 302static struct miscdevice wdt_miscdev = {
 303        .minor  =       WATCHDOG_MINOR,
 304        .name   =       "watchdog",
 305        .fops   =       &wdt_fops,
 306};
 307
 308/*
 309 *      Notifier for system down
 310 */
 311
 312static int wdt_notify_sys(struct notifier_block *this,
 313                                        unsigned long code, void *unused)
 314{
 315        if (code == SYS_DOWN || code == SYS_HALT)
 316                wdt_turnoff();
 317
 318        if (code == SYS_RESTART) {
 319                /*
 320                 * Cobalt devices have no way of rebooting themselves other
 321                 * than getting the watchdog to pull reset, so we restart the
 322                 * watchdog on reboot with no heartbeat
 323                 */
 324                wdt_change(WDT_ENABLE);
 325                printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n");
 326        }
 327        return NOTIFY_DONE;
 328}
 329
 330/*
 331 *      The WDT needs to learn about soft shutdowns in order to
 332 *      turn the timebomb registers off.
 333 */
 334
 335static struct notifier_block wdt_notifier = {
 336        .notifier_call = wdt_notify_sys,
 337};
 338
 339static void __exit alim7101_wdt_unload(void)
 340{
 341        wdt_turnoff();
 342        /* Deregister */
 343        misc_deregister(&wdt_miscdev);
 344        unregister_reboot_notifier(&wdt_notifier);
 345        pci_dev_put(alim7101_pmu);
 346}
 347
 348static int __init alim7101_wdt_init(void)
 349{
 350        int rc = -EBUSY;
 351        struct pci_dev *ali1543_south;
 352        char tmp;
 353
 354        printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");
 355        alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
 356                NULL);
 357        if (!alim7101_pmu) {
 358                printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n");
 359                return -EBUSY;
 360        }
 361
 362        /* Set the WDT in the PMU to 1 second */
 363        pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
 364
 365        ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
 366                NULL);
 367        if (!ali1543_south) {
 368                printk(KERN_INFO PFX
 369                        "ALi 1543 South-Bridge not present - WDT not set\n");
 370                goto err_out;
 371        }
 372        pci_read_config_byte(ali1543_south, 0x5e, &tmp);
 373        pci_dev_put(ali1543_south);
 374        if ((tmp & 0x1e) == 0x00) {
 375                if (!use_gpio) {
 376                        printk(KERN_INFO PFX "Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
 377                        goto err_out;
 378                }
 379                nowayout = 1;
 380        } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
 381                printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
 382                goto err_out;
 383        }
 384
 385        if (timeout < 1 || timeout > 3600) {
 386                /* arbitrary upper limit */
 387                timeout = WATCHDOG_TIMEOUT;
 388                printk(KERN_INFO PFX
 389                        "timeout value must be 1 <= x <= 3600, using %d\n",
 390                                                                timeout);
 391        }
 392
 393        rc = register_reboot_notifier(&wdt_notifier);
 394        if (rc) {
 395                printk(KERN_ERR PFX
 396                        "cannot register reboot notifier (err=%d)\n", rc);
 397                goto err_out;
 398        }
 399
 400        rc = misc_register(&wdt_miscdev);
 401        if (rc) {
 402                printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 403                        wdt_miscdev.minor, rc);
 404                goto err_out_reboot;
 405        }
 406
 407        if (nowayout)
 408                __module_get(THIS_MODULE);
 409
 410        printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
 411                timeout, nowayout);
 412        return 0;
 413
 414err_out_reboot:
 415        unregister_reboot_notifier(&wdt_notifier);
 416err_out:
 417        pci_dev_put(alim7101_pmu);
 418        return rc;
 419}
 420
 421module_init(alim7101_wdt_init);
 422module_exit(alim7101_wdt_unload);
 423
 424static struct pci_device_id alim7101_pci_tbl[] __devinitdata = {
 425        { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
 426        { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
 427        { }
 428};
 429
 430MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
 431
 432MODULE_AUTHOR("Steve Hill");
 433MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
 434MODULE_LICENSE("GPL");
 435MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 436