drivers/watchdog/sp5100_tco.c

   1 /*
   2  *      sp5100_tco :    TCO timer driver for sp5100 chipsets
   3  *
   4  *      (c) Copyright 2009 Google Inc., All Rights Reserved.
   5  *
   6  *      Based on 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  *      See AMD Publication 43009 "AMD SB700/710/750 Register Reference Guide"
  17  */
  18
  19 /*
  20  *      Includes, defines, variables, module parameters, ...
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/types.h>
  26 #include <linux/miscdevice.h>
  27 #include <linux/watchdog.h>
  28 #include <linux/init.h>
  29 #include <linux/fs.h>
  30 #include <linux/pci.h>
  31 #include <linux/ioport.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/uaccess.h>
  34 #include <linux/io.h>
  35
  36 #include "sp5100_tco.h"
  37
  38 /* Module and version information */
  39 #define TCO_VERSION "0.01"
  40 #define TCO_MODULE_NAME "SP5100 TCO timer"
  41 #define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
  42 #define PFX TCO_MODULE_NAME ": "
  43
  44 /* internal variables */
  45 static void __iomem *tcobase;
  46 static unsigned int pm_iobase;
  47 static DEFINE_SPINLOCK(tco_lock);       /* Guards the hardware */
  48 static unsigned long timer_alive;
  49 static char tco_expect_close;
  50 static struct pci_dev *sp5100_tco_pci;
  51
  52 /* the watchdog platform device */
  53 static struct platform_device *sp5100_tco_platform_device;
  54
  55 /* module parameters */
  56
  57 #define WATCHDOG_HEARTBEAT 60   /* 60 sec default heartbeat. */
  58 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  59 module_param(heartbeat, int, 0);
  60 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
  61                  __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  62
  63 static int nowayout = WATCHDOG_NOWAYOUT;
  64 module_param(nowayout, int, 0);
  65 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
  66                 " (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  67
  68 /*
  69  * Some TCO specific functions
  70  */
  71 static void tco_timer_start(void)
  72 {
  73         u32 val;
  74         unsigned long flags;
  75
  76         spin_lock_irqsave(&tco_lock, flags);
  77         val = readl(SP5100_WDT_CONTROL(tcobase));
  78         val |= SP5100_WDT_START_STOP_BIT;
  79         writel(val, SP5100_WDT_CONTROL(tcobase));
  80         spin_unlock_irqrestore(&tco_lock, flags);
  81 }
  82
  83 static void tco_timer_stop(void)
  84 {
  85         u32 val;
  86         unsigned long flags;
  87
  88         spin_lock_irqsave(&tco_lock, flags);
  89         val = readl(SP5100_WDT_CONTROL(tcobase));
  90         val &= ~SP5100_WDT_START_STOP_BIT;
  91         writel(val, SP5100_WDT_CONTROL(tcobase));
  92         spin_unlock_irqrestore(&tco_lock, flags);
  93 }
  94
  95 static void tco_timer_keepalive(void)
  96 {
  97         u32 val;
  98         unsigned long flags;
  99
 100         spin_lock_irqsave(&tco_lock, flags);
 101         val = readl(SP5100_WDT_CONTROL(tcobase));
 102         val |= SP5100_WDT_TRIGGER_BIT;
 103         writel(val, SP5100_WDT_CONTROL(tcobase));
 104         spin_unlock_irqrestore(&tco_lock, flags);
 105 }
 106
 107 static int tco_timer_set_heartbeat(int t)
 108 {
 109         unsigned long flags;
 110
 111         if (t < 0 || t > 0xffff)
 112                 return -EINVAL;
 113
 114         /* Write new heartbeat to watchdog */
 115         spin_lock_irqsave(&tco_lock, flags);
 116         writel(t, SP5100_WDT_COUNT(tcobase));
 117         spin_unlock_irqrestore(&tco_lock, flags);
 118
 119         heartbeat = t;
 120         return 0;
 121 }
 122
 123 /*
 124  *      /dev/watchdog handling
 125  */
 126
 127 static int sp5100_tco_open(struct inode *inode, struct file *file)
 128 {
 129         /* /dev/watchdog can only be opened once */
 130         if (test_and_set_bit(0, &timer_alive))
 131                 return -EBUSY;
 132
 133         /* Reload and activate timer */
 134         tco_timer_start();
 135         tco_timer_keepalive();
 136         return nonseekable_open(inode, file);
 137 }
 138
 139 static int sp5100_tco_release(struct inode *inode, struct file *file)
 140 {
 141         /* Shut off the timer. */
 142         if (tco_expect_close == 42) {
 143                 tco_timer_stop();
 144         } else {
 145                 printk(KERN_CRIT PFX
 146                         "Unexpected close, not stopping watchdog!\n");
 147                 tco_timer_keepalive();
 148         }
 149         clear_bit(0, &timer_alive);
 150         tco_expect_close = 0;
 151         return 0;
 152 }
 153
 154 static ssize_t sp5100_tco_write(struct file *file, const char __user *data,
 155                                 size_t len, loff_t *ppos)
 156 {
 157         /* See if we got the magic character 'V' and reload the timer */
 158         if (len) {
 159                 if (!nowayout) {
 160                         size_t i;
 161
 162                         /* note: just in case someone wrote the magic character
 163                          * five months ago... */
 164                         tco_expect_close = 0;
 165
 166                         /* scan to see whether or not we got the magic character
 167                          */
 168                         for (i = 0; i != len; i++) {
 169                                 char c;
 170                                 if (get_user(c, data + i))
 171                                         return -EFAULT;
 172                                 if (c == 'V')
 173                                         tco_expect_close = 42;
 174                         }
 175                 }
 176
 177                 /* someone wrote to us, we should reload the timer */
 178                 tco_timer_keepalive();
 179         }
 180         return len;
 181 }
 182
 183 static long sp5100_tco_ioctl(struct file *file, unsigned int cmd,
 184                              unsigned long arg)
 185 {
 186         int new_options, retval = -EINVAL;
 187         int new_heartbeat;
 188         void __user *argp = (void __user *)arg;
 189         int __user *p = argp;
 190         static const struct watchdog_info ident = {
 191                 .options =              WDIOF_SETTIMEOUT |
 192                                         WDIOF_KEEPALIVEPING |
 193                                         WDIOF_MAGICCLOSE,
 194                 .firmware_version =     0,
 195                 .identity =             TCO_MODULE_NAME,
 196         };
 197
 198         switch (cmd) {
 199         case WDIOC_GETSUPPORT:
 200                 return copy_to_user(argp, &ident,
 201                         sizeof(ident)) ? -EFAULT : 0;
 202         case WDIOC_GETSTATUS:
 203         case WDIOC_GETBOOTSTATUS:
 204                 return put_user(0, p);
 205         case WDIOC_SETOPTIONS:
 206                 if (get_user(new_options, p))
 207                         return -EFAULT;
 208                 if (new_options & WDIOS_DISABLECARD) {
 209                         tco_timer_stop();
 210                         retval = 0;
 211                 }
 212                 if (new_options & WDIOS_ENABLECARD) {
 213                         tco_timer_start();
 214                         tco_timer_keepalive();
 215                         retval = 0;
 216                 }
 217                 return retval;
 218         case WDIOC_KEEPALIVE:
 219                 tco_timer_keepalive();
 220                 return 0;
 221         case WDIOC_SETTIMEOUT:
 222                 if (get_user(new_heartbeat, p))
 223                         return -EFAULT;
 224                 if (tco_timer_set_heartbeat(new_heartbeat))
 225                         return -EINVAL;
 226                 tco_timer_keepalive();
 227                 /* Fall through */
 228         case WDIOC_GETTIMEOUT:
 229                 return put_user(heartbeat, p);
 230         default:
 231                 return -ENOTTY;
 232         }
 233 }
 234
 235 /*
 236  * Kernel Interfaces
 237  */
 238
 239 static const struct file_operations sp5100_tco_fops = {
 240         .owner =                THIS_MODULE,
 241         .llseek =               no_llseek,
 242         .write =                sp5100_tco_write,
 243         .unlocked_ioctl =       sp5100_tco_ioctl,
 244         .open =                 sp5100_tco_open,
 245         .release =              sp5100_tco_release,
 246 };
 247
 248 static struct miscdevice sp5100_tco_miscdev = {
 249         .minor =        WATCHDOG_MINOR,
 250         .name =         "watchdog",
 251         .fops =         &sp5100_tco_fops,
 252 };
 253
 254 /*
 255  * Data for PCI driver interface
 256  *
 257  * This data only exists for exporting the supported
 258  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 259  * register a pci_driver, because someone else might
 260  * want to register another driver on the same PCI id.
 261  */
 262 static struct pci_device_id sp5100_tco_pci_tbl[] = {
 263         { PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS, PCI_ANY_ID,
 264           PCI_ANY_ID, },
 265         { 0, },                 /* End of list */
 266 };
 267 MODULE_DEVICE_TABLE(pci, sp5100_tco_pci_tbl);
 268
 269 /*
 270  * Init & exit routines
 271  */
 272
 273 static unsigned char __devinit sp5100_tco_setupdevice(void)
 274 {
 275         struct pci_dev *dev = NULL;
 276         u32 val;
 277
 278         /* Match the PCI device */
 279         for_each_pci_dev(dev) {
 280                 if (pci_match_id(sp5100_tco_pci_tbl, dev) != NULL) {
 281                         sp5100_tco_pci = dev;
 282                         break;
 283                 }
 284         }
 285
 286         if (!sp5100_tco_pci)
 287                 return 0;
 288
 289         /* Request the IO ports used by this driver */
 290         pm_iobase = SP5100_IO_PM_INDEX_REG;
 291         if (!request_region(pm_iobase, SP5100_PM_IOPORTS_SIZE, "SP5100 TCO")) {
 292                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 293                         pm_iobase);
 294                 goto exit;
 295         }
 296
 297         /* Find the watchdog base address. */
 298         outb(SP5100_PM_WATCHDOG_BASE3, SP5100_IO_PM_INDEX_REG);
 299         val = inb(SP5100_IO_PM_DATA_REG);
 300         outb(SP5100_PM_WATCHDOG_BASE2, SP5100_IO_PM_INDEX_REG);
 301         val = val << 8 | inb(SP5100_IO_PM_DATA_REG);
 302         outb(SP5100_PM_WATCHDOG_BASE1, SP5100_IO_PM_INDEX_REG);
 303         val = val << 8 | inb(SP5100_IO_PM_DATA_REG);
 304         outb(SP5100_PM_WATCHDOG_BASE0, SP5100_IO_PM_INDEX_REG);
 305         /* Low three bits of BASE0 are reserved. */
 306         val = val << 8 | (inb(SP5100_IO_PM_DATA_REG) & 0xf8);
 307
 308         tcobase = ioremap(val, SP5100_WDT_MEM_MAP_SIZE);
 309         if (tcobase == 0) {
 310                 printk(KERN_ERR PFX "failed to get tcobase address\n");
 311                 goto unreg_region;
 312         }
 313
 314         /* Enable watchdog decode bit */
 315         pci_read_config_dword(sp5100_tco_pci,
 316                               SP5100_PCI_WATCHDOG_MISC_REG,
 317                               &val);
 318
 319         val |= SP5100_PCI_WATCHDOG_DECODE_EN;
 320
 321         pci_write_config_dword(sp5100_tco_pci,
 322                                SP5100_PCI_WATCHDOG_MISC_REG,
 323                                val);
 324
 325         /* Enable Watchdog timer and set the resolution to 1 sec. */
 326         outb(SP5100_PM_WATCHDOG_CONTROL, SP5100_IO_PM_INDEX_REG);
 327         val = inb(SP5100_IO_PM_DATA_REG);
 328         val |= SP5100_PM_WATCHDOG_SECOND_RES;
 329         val &= ~SP5100_PM_WATCHDOG_DISABLE;
 330         outb(val, SP5100_IO_PM_DATA_REG);
 331
 332         /* Check that the watchdog action is set to reset the system. */
 333         val = readl(SP5100_WDT_CONTROL(tcobase));
 334         val &= ~SP5100_PM_WATCHDOG_ACTION_RESET;
 335         writel(val, SP5100_WDT_CONTROL(tcobase));
 336
 337         /* Set a reasonable heartbeat before we stop the timer */
 338         tco_timer_set_heartbeat(heartbeat);
 339
 340         /*
 341          * Stop the TCO before we change anything so we don't race with
 342          * a zeroed timer.
 343          */
 344         tco_timer_stop();
 345
 346         /* Done */
 347         return 1;
 348
 349         iounmap(tcobase);
 350 unreg_region:
 351         release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
 352 exit:
 353         return 0;
 354 }
 355
 356 static int __devinit sp5100_tco_init(struct platform_device *dev)
 357 {
 358         int ret;
 359         u32 val;
 360
 361         /* Check whether or not the hardware watchdog is there. If found, then
 362          * set it up.
 363          */
 364         if (!sp5100_tco_setupdevice())
 365                 return -ENODEV;
 366
 367         /* Check to see if last reboot was due to watchdog timeout */
 368         printk(KERN_INFO PFX "Watchdog reboot %sdetected.\n",
 369                readl(SP5100_WDT_CONTROL(tcobase)) & SP5100_PM_WATCHDOG_FIRED ?
 370                       "" : "not ");
 371
 372         /* Clear out the old status */
 373         val = readl(SP5100_WDT_CONTROL(tcobase));
 374         val &= ~SP5100_PM_WATCHDOG_FIRED;
 375         writel(val, SP5100_WDT_CONTROL(tcobase));
 376
 377         /*
 378          * Check that the heartbeat value is within it's range.
 379          * If not, reset to the default.
 380          */
 381         if (tco_timer_set_heartbeat(heartbeat)) {
 382                 heartbeat = WATCHDOG_HEARTBEAT;
 383                 tco_timer_set_heartbeat(heartbeat);
 384         }
 385
 386         ret = misc_register(&sp5100_tco_miscdev);
 387         if (ret != 0) {
 388                 printk(KERN_ERR PFX "cannot register miscdev on minor="
 389                        "%d (err=%d)\n",
 390                        WATCHDOG_MINOR, ret);
 391                 goto exit;
 392         }
 393
 394         clear_bit(0, &timer_alive);
 395
 396         printk(KERN_INFO PFX "initialized (0x%p). heartbeat=%d sec"
 397                 " (nowayout=%d)\n",
 398                 tcobase, heartbeat, nowayout);
 399
 400         return 0;
 401
 402 exit:
 403         iounmap(tcobase);
 404         release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
 405         return ret;
 406 }
 407
 408 static void __devexit sp5100_tco_cleanup(void)
 409 {
 410         /* Stop the timer before we leave */
 411         if (!nowayout)
 412                 tco_timer_stop();
 413
 414         /* Deregister */
 415         misc_deregister(&sp5100_tco_miscdev);
 416         iounmap(tcobase);
 417         release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
 418 }
 419
 420 static int __devexit sp5100_tco_remove(struct platform_device *dev)
 421 {
 422         if (tcobase)
 423                 sp5100_tco_cleanup();
 424         return 0;
 425 }
 426
 427 static void sp5100_tco_shutdown(struct platform_device *dev)
 428 {
 429         tco_timer_stop();
 430 }
 431
 432 static struct platform_driver sp5100_tco_driver = {
 433         .probe          = sp5100_tco_init,
 434         .remove         = __devexit_p(sp5100_tco_remove),
 435         .shutdown       = sp5100_tco_shutdown,
 436         .driver         = {
 437                 .owner  = THIS_MODULE,
 438                 .name   = TCO_MODULE_NAME,
 439         },
 440 };
 441
 442 static int __init sp5100_tco_init_module(void)
 443 {
 444         int err;
 445
 446         printk(KERN_INFO PFX "SP5100 TCO WatchDog Timer Driver v%s\n",
 447                TCO_VERSION);
 448
 449         err = platform_driver_register(&sp5100_tco_driver);
 450         if (err)
 451                 return err;
 452
 453         sp5100_tco_platform_device = platform_device_register_simple(
 454                                         TCO_MODULE_NAME, -1, NULL, 0);
 455         if (IS_ERR(sp5100_tco_platform_device)) {
 456                 err = PTR_ERR(sp5100_tco_platform_device);
 457                 goto unreg_platform_driver;
 458         }
 459
 460         return 0;
 461
 462 unreg_platform_driver:
 463         platform_driver_unregister(&sp5100_tco_driver);
 464         return err;
 465 }
 466
 467 static void __exit sp5100_tco_cleanup_module(void)
 468 {
 469         platform_device_unregister(sp5100_tco_platform_device);
 470         platform_driver_unregister(&sp5100_tco_driver);
 471         printk(KERN_INFO PFX "SP5100 TCO Watchdog Module Unloaded.\n");
 472 }
 473
 474 module_init(sp5100_tco_init_module);
 475 module_exit(sp5100_tco_cleanup_module);
 476
 477 MODULE_AUTHOR("Priyanka Gupta");
 478 MODULE_DESCRIPTION("TCO timer driver for SP5100 chipset");
 479 MODULE_LICENSE("GPL");
 480 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);