release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/watchdog/i6300esb.c

   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 #include <linux/module.h>
  31 #include <linux/types.h>
  32 #include <linux/kernel.h>
  33 #include <linux/fs.h>
  34 #include <linux/mm.h>
  35 #include <linux/miscdevice.h>
  36 #include <linux/watchdog.h>
  37 #include <linux/init.h>
  38 #include <linux/pci.h>
  39 #include <linux/ioport.h>
  40 #include <linux/uaccess.h>
  41 #include <linux/io.h>
  42
  43 /* Module and version information */
  44 #define ESB_VERSION "0.05"
  45 #define ESB_MODULE_NAME "i6300ESB timer"
  46 #define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
  47 #define PFX ESB_MODULE_NAME ": "
  48
  49 /* PCI configuration registers */
  50 #define ESB_CONFIG_REG  0x60            /* Config register                   */
  51 #define ESB_LOCK_REG    0x68            /* WDT lock register                 */
  52
  53 /* Memory mapped registers */
  54 #define ESB_TIMER1_REG (BASEADDR + 0x00)/* Timer1 value after each reset     */
  55 #define ESB_TIMER2_REG (BASEADDR + 0x04)/* Timer2 value after each reset     */
  56 #define ESB_GINTSR_REG (BASEADDR + 0x08)/* General Interrupt Status Register */
  57 #define ESB_RELOAD_REG (BASEADDR + 0x0c)/* Reload register                   */
  58
  59 /* Lock register bits */
  60 #define ESB_WDT_FUNC    (0x01 << 2)   /* Watchdog functionality            */
  61 #define ESB_WDT_ENABLE  (0x01 << 1)   /* Enable WDT                        */
  62 #define ESB_WDT_LOCK    (0x01 << 0)   /* Lock (nowayout)                   */
  63
  64 /* Config register bits */
  65 #define ESB_WDT_REBOOT  (0x01 << 5)   /* Enable reboot on timeout          */
  66 #define ESB_WDT_FREQ    (0x01 << 2)   /* Decrement frequency               */
  67 #define ESB_WDT_INTTYPE (0x03 << 0)   /* Interrupt type on timer1 timeout  */
  68
  69 /* Reload register bits */
  70 #define ESB_WDT_TIMEOUT (0x01 << 9)    /* Watchdog timed out                */
  71 #define ESB_WDT_RELOAD  (0x01 << 8)    /* prevent timeout                   */
  72
  73 /* Magic constants */
  74 #define ESB_UNLOCK1     0x80            /* Step 1 to unlock reset registers  */
  75 #define ESB_UNLOCK2     0x86            /* Step 2 to unlock reset registers  */
  76
  77 /* internal variables */
  78 static void __iomem *BASEADDR;
  79 static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */
  80 static unsigned long timer_alive;
  81 static struct pci_dev *esb_pci;
  82 static unsigned short triggered; /* The status of the watchdog upon boot */
  83 static char esb_expect_close;
  84
  85 /* We can only use 1 card due to the /dev/watchdog restriction */
  86 static int cards_found;
  87
  88 /* module parameters */
  89 /* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
  90 #define WATCHDOG_HEARTBEAT 30
  91 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  92 module_param(heartbeat, int, 0);
  93 MODULE_PARM_DESC(heartbeat,
  94                 "Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
  95                                 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  96
  97 static int nowayout = WATCHDOG_NOWAYOUT;
  98 module_param(nowayout, int, 0);
  99 MODULE_PARM_DESC(nowayout,
 100                 "Watchdog cannot be stopped once started (default="
 101                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 102
 103 /*
 104  * Some i6300ESB specific functions
 105  */
 106
 107 /*
 108  * Prepare for reloading the timer by unlocking the proper registers.
 109  * This is performed by first writing 0x80 followed by 0x86 to the
 110  * reload register. After this the appropriate registers can be written
 111  * to once before they need to be unlocked again.
 112  */
 113 static inline void esb_unlock_registers(void)
 114 {
 115         writew(ESB_UNLOCK1, ESB_RELOAD_REG);
 116         writew(ESB_UNLOCK2, ESB_RELOAD_REG);
 117 }
 118
 119 static int esb_timer_start(void)
 120 {
 121         u8 val;
 122
 123         spin_lock(&esb_lock);
 124         esb_unlock_registers();
 125         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 126         /* Enable or Enable + Lock? */
 127         val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
 128         pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
 129         spin_unlock(&esb_lock);
 130         return 0;
 131 }
 132
 133 static int esb_timer_stop(void)
 134 {
 135         u8 val;
 136
 137         spin_lock(&esb_lock);
 138         /* First, reset timers as suggested by the docs */
 139         esb_unlock_registers();
 140         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 141         /* Then disable the WDT */
 142         pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
 143         pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
 144         spin_unlock(&esb_lock);
 145
 146         /* Returns 0 if the timer was disabled, non-zero otherwise */
 147         return val & ESB_WDT_ENABLE;
 148 }
 149
 150 static void esb_timer_keepalive(void)
 151 {
 152         spin_lock(&esb_lock);
 153         esb_unlock_registers();
 154         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 155         spin_unlock(&esb_lock);
 156 }
 157
 158 static int esb_timer_set_heartbeat(int time)
 159 {
 160         u32 val;
 161
 162         if (time < 0x1 || time > (2 * 0x03ff))
 163                 return -EINVAL;
 164
 165         spin_lock(&esb_lock);
 166
 167         /* We shift by 9, so if we are passed a value of 1 sec,
 168          * val will be 1 << 9 = 512, then write that to two
 169          * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
 170          */
 171         val = time << 9;
 172
 173         /* Write timer 1 */
 174         esb_unlock_registers();
 175         writel(val, ESB_TIMER1_REG);
 176
 177         /* Write timer 2 */
 178         esb_unlock_registers();
 179         writel(val, ESB_TIMER2_REG);
 180
 181         /* Reload */
 182         esb_unlock_registers();
 183         writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
 184
 185
 186         /* Done */
 187         heartbeat = time;
 188         spin_unlock(&esb_lock);
 189         return 0;
 190 }
 191
 192 /*
 193  *      /dev/watchdog handling
 194  */
 195
 196 static int esb_open(struct inode *inode, struct file *file)
 197 {
 198         /* /dev/watchdog can only be opened once */
 199         if (test_and_set_bit(0, &timer_alive))
 200                 return -EBUSY;
 201
 202         /* Reload and activate timer */
 203         esb_timer_start();
 204
 205         return nonseekable_open(inode, file);
 206 }
 207
 208 static int esb_release(struct inode *inode, struct file *file)
 209 {
 210         /* Shut off the timer. */
 211         if (esb_expect_close == 42)
 212                 esb_timer_stop();
 213         else {
 214                 printk(KERN_CRIT PFX
 215                                 "Unexpected close, not stopping watchdog!\n");
 216                 esb_timer_keepalive();
 217         }
 218         clear_bit(0, &timer_alive);
 219         esb_expect_close = 0;
 220         return 0;
 221 }
 222
 223 static ssize_t esb_write(struct file *file, const char __user *data,
 224                           size_t len, loff_t *ppos)
 225 {
 226         /* See if we got the magic character 'V' and reload the timer */
 227         if (len) {
 228                 if (!nowayout) {
 229                         size_t i;
 230
 231                         /* note: just in case someone wrote the magic character
 232                          * five months ago... */
 233                         esb_expect_close = 0;
 234
 235                         /* scan to see whether or not we got the
 236                          * magic character */
 237                         for (i = 0; i != len; i++) {
 238                                 char c;
 239                                 if (get_user(c, data + i))
 240                                         return -EFAULT;
 241                                 if (c == 'V')
 242                                         esb_expect_close = 42;
 243                         }
 244                 }
 245
 246                 /* someone wrote to us, we should reload the timer */
 247                 esb_timer_keepalive();
 248         }
 249         return len;
 250 }
 251
 252 static long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 253 {
 254         int new_options, retval = -EINVAL;
 255         int new_heartbeat;
 256         void __user *argp = (void __user *)arg;
 257         int __user *p = argp;
 258         static const struct watchdog_info ident = {
 259                 .options =              WDIOF_SETTIMEOUT |
 260                                         WDIOF_KEEPALIVEPING |
 261                                         WDIOF_MAGICCLOSE,
 262                 .firmware_version =     0,
 263                 .identity =             ESB_MODULE_NAME,
 264         };
 265
 266         switch (cmd) {
 267         case WDIOC_GETSUPPORT:
 268                 return copy_to_user(argp, &ident,
 269                                         sizeof(ident)) ? -EFAULT : 0;
 270
 271         case WDIOC_GETSTATUS:
 272                 return put_user(0, p);
 273
 274         case WDIOC_GETBOOTSTATUS:
 275                 return put_user(triggered, p);
 276
 277         case WDIOC_SETOPTIONS:
 278         {
 279                 if (get_user(new_options, p))
 280                         return -EFAULT;
 281
 282                 if (new_options & WDIOS_DISABLECARD) {
 283                         esb_timer_stop();
 284                         retval = 0;
 285                 }
 286
 287                 if (new_options & WDIOS_ENABLECARD) {
 288                         esb_timer_start();
 289                         retval = 0;
 290                 }
 291                 return retval;
 292         }
 293         case WDIOC_KEEPALIVE:
 294                 esb_timer_keepalive();
 295                 return 0;
 296
 297         case WDIOC_SETTIMEOUT:
 298         {
 299                 if (get_user(new_heartbeat, p))
 300                         return -EFAULT;
 301                 if (esb_timer_set_heartbeat(new_heartbeat))
 302                         return -EINVAL;
 303                 esb_timer_keepalive();
 304                 /* Fall */
 305         }
 306         case WDIOC_GETTIMEOUT:
 307                 return put_user(heartbeat, p);
 308         default:
 309                 return -ENOTTY;
 310         }
 311 }
 312
 313 /*
 314  *      Kernel Interfaces
 315  */
 316
 317 static const struct file_operations esb_fops = {
 318         .owner = THIS_MODULE,
 319         .llseek = no_llseek,
 320         .write = esb_write,
 321         .unlocked_ioctl = esb_ioctl,
 322         .open = esb_open,
 323         .release = esb_release,
 324 };
 325
 326 static struct miscdevice esb_miscdev = {
 327         .minor = WATCHDOG_MINOR,
 328         .name = "watchdog",
 329         .fops = &esb_fops,
 330 };
 331
 332 /*
 333  * Data for PCI driver interface
 334  */
 335 static struct pci_device_id esb_pci_tbl[] = {
 336         { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
 337         { 0, },                 /* End of list */
 338 };
 339 MODULE_DEVICE_TABLE(pci, esb_pci_tbl);
 340
 341 /*
 342  *      Init & exit routines
 343  */
 344
 345 static unsigned char __devinit esb_getdevice(struct pci_dev *pdev)
 346 {
 347         if (pci_enable_device(pdev)) {
 348                 printk(KERN_ERR PFX "failed to enable device\n");
 349                 goto err_devput;
 350         }
 351
 352         if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
 353                 printk(KERN_ERR PFX "failed to request region\n");
 354                 goto err_disable;
 355         }
 356
 357         BASEADDR = pci_ioremap_bar(pdev, 0);
 358         if (BASEADDR == NULL) {
 359                 /* Something's wrong here, BASEADDR has to be set */
 360                 printk(KERN_ERR PFX "failed to get BASEADDR\n");
 361                 goto err_release;
 362         }
 363
 364         /* Done */
 365         esb_pci = pdev;
 366         return 1;
 367
 368 err_release:
 369         pci_release_region(pdev, 0);
 370 err_disable:
 371         pci_disable_device(pdev);
 372 err_devput:
 373         return 0;
 374 }
 375
 376 static void __devinit esb_initdevice(void)
 377 {
 378         u8 val1;
 379         u16 val2;
 380
 381         /*
 382          * Config register:
 383          * Bit    5 : 0 = Enable WDT_OUTPUT
 384          * Bit    2 : 0 = set the timer frequency to the PCI clock
 385          * divided by 2^15 (approx 1KHz).
 386          * Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
 387          * The watchdog has two timers, it can be setup so that the
 388          * expiry of timer1 results in an interrupt and the expiry of
 389          * timer2 results in a reboot. We set it to not generate
 390          * any interrupts as there is not much we can do with it
 391          * right now.
 392          */
 393         pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
 394
 395         /* Check that the WDT isn't already locked */
 396         pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
 397         if (val1 & ESB_WDT_LOCK)
 398                 printk(KERN_WARNING PFX "nowayout already set\n");
 399
 400         /* Set the timer to watchdog mode and disable it for now */
 401         pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
 402
 403         /* Check if the watchdog was previously triggered */
 404         esb_unlock_registers();
 405         val2 = readw(ESB_RELOAD_REG);
 406         if (val2 & ESB_WDT_TIMEOUT)
 407                 triggered = WDIOF_CARDRESET;
 408
 409         /* Reset WDT_TIMEOUT flag and timers */
 410         esb_unlock_registers();
 411         writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);
 412
 413         /* And set the correct timeout value */
 414         esb_timer_set_heartbeat(heartbeat);
 415 }
 416
 417 static int __devinit esb_probe(struct pci_dev *pdev,
 418                 const struct pci_device_id *ent)
 419 {
 420         int ret;
 421
 422         cards_found++;
 423         if (cards_found == 1)
 424                 printk(KERN_INFO PFX "Intel 6300ESB WatchDog Timer Driver v%s\n",
 425                         ESB_VERSION);
 426
 427         if (cards_found > 1) {
 428                 printk(KERN_ERR PFX "This driver only supports 1 device\n");
 429                 return -ENODEV;
 430         }
 431
 432         /* Check whether or not the hardware watchdog is there */
 433         if (!esb_getdevice(pdev) || esb_pci == NULL)
 434                 return -ENODEV;
 435
 436         /* Check that the heartbeat value is within it's range;
 437            if not reset to the default */
 438         if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
 439                 heartbeat = WATCHDOG_HEARTBEAT;
 440                 printk(KERN_INFO PFX
 441                         "heartbeat value must be 1<heartbeat<2046, using %d\n",
 442                                                                 heartbeat);
 443         }
 444
 445         /* Initialize the watchdog and make sure it does not run */
 446         esb_initdevice();
 447
 448         /* Register the watchdog so that userspace has access to it */
 449         ret = misc_register(&esb_miscdev);
 450         if (ret != 0) {
 451                 printk(KERN_ERR PFX
 452                         "cannot register miscdev on minor=%d (err=%d)\n",
 453                                                         WATCHDOG_MINOR, ret);
 454                 goto err_unmap;
 455         }
 456         printk(KERN_INFO PFX
 457                 "initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
 458                                                 BASEADDR, heartbeat, nowayout);
 459         return 0;
 460
 461 err_unmap:
 462         iounmap(BASEADDR);
 463         pci_release_region(esb_pci, 0);
 464         pci_disable_device(esb_pci);
 465         esb_pci = NULL;
 466         return ret;
 467 }
 468
 469 static void __devexit esb_remove(struct pci_dev *pdev)
 470 {
 471         /* Stop the timer before we leave */
 472         if (!nowayout)
 473                 esb_timer_stop();
 474
 475         /* Deregister */
 476         misc_deregister(&esb_miscdev);
 477         iounmap(BASEADDR);
 478         pci_release_region(esb_pci, 0);
 479         pci_disable_device(esb_pci);
 480         esb_pci = NULL;
 481 }
 482
 483 static void esb_shutdown(struct pci_dev *pdev)
 484 {
 485         esb_timer_stop();
 486 }
 487
 488 static struct pci_driver esb_driver = {
 489         .name           = ESB_MODULE_NAME,
 490         .id_table       = esb_pci_tbl,
 491         .probe          = esb_probe,
 492         .remove         = __devexit_p(esb_remove),
 493         .shutdown       = esb_shutdown,
 494 };
 495
 496 static int __init watchdog_init(void)
 497 {
 498         return pci_register_driver(&esb_driver);
 499 }
 500
 501 static void __exit watchdog_cleanup(void)
 502 {
 503         pci_unregister_driver(&esb_driver);
 504         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
 505 }
 506
 507 module_init(watchdog_init);
 508 module_exit(watchdog_cleanup);
 509
 510 MODULE_AUTHOR("Ross Biro and David Härdeman");
 511 MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
 512 MODULE_LICENSE("GPL");
 513 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);