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 u32 tcobase_phys;
  46 static void __iomem *tcobase;
  47 static unsigned int pm_iobase;
  48 static DEFINE_SPINLOCK(tco_lock);       /* Guards the hardware */
  49 static unsigned long timer_alive;
  50 static char tco_expect_close;
  51 static struct pci_dev *sp5100_tco_pci;
  52
  53 /* the watchdog platform device */
  54 static struct platform_device *sp5100_tco_platform_device;
  55
  56 /* module parameters */
  57
  58 #define WATCHDOG_HEARTBEAT 60   /* 60 sec default heartbeat. */
  59 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
  60 module_param(heartbeat, int, 0);
  61 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
  62                  __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
  63
  64 static int nowayout = WATCHDOG_NOWAYOUT;
  65 module_param(nowayout, int, 0);
  66 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
  67                 " (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  68
  69 /*
  70  * Some TCO specific functions
  71  */
  72 static void tco_timer_start(void)
  73 {
  74         u32 val;
  75         unsigned long flags;
  76
  77         spin_lock_irqsave(&tco_lock, flags);
  78         val = readl(SP5100_WDT_CONTROL(tcobase));
  79         val |= SP5100_WDT_START_STOP_BIT;
  80         writel(val, SP5100_WDT_CONTROL(tcobase));
  81         spin_unlock_irqrestore(&tco_lock, flags);
  82 }
  83
  84 static void tco_timer_stop(void)
  85 {
  86         u32 val;
  87         unsigned long flags;
  88
  89         spin_lock_irqsave(&tco_lock, flags);
  90         val = readl(SP5100_WDT_CONTROL(tcobase));
  91         val &= ~SP5100_WDT_START_STOP_BIT;
  92         writel(val, SP5100_WDT_CONTROL(tcobase));
  93         spin_unlock_irqrestore(&tco_lock, flags);
  94 }
  95
  96 static void tco_timer_keepalive(void)
  97 {
  98         u32 val;
  99         unsigned long flags;
 100
 101         spin_lock_irqsave(&tco_lock, flags);
 102         val = readl(SP5100_WDT_CONTROL(tcobase));
 103         val |= SP5100_WDT_TRIGGER_BIT;
 104         writel(val, SP5100_WDT_CONTROL(tcobase));
 105         spin_unlock_irqrestore(&tco_lock, flags);
 106 }
 107
 108 static int tco_timer_set_heartbeat(int t)
 109 {
 110         unsigned long flags;
 111
 112         if (t < 0 || t > 0xffff)
 113                 return -EINVAL;
 114
 115         /* Write new heartbeat to watchdog */
 116         spin_lock_irqsave(&tco_lock, flags);
 117         writel(t, SP5100_WDT_COUNT(tcobase));
 118         spin_unlock_irqrestore(&tco_lock, flags);
 119
 120         heartbeat = t;
 121         return 0;
 122 }
 123
 124 /*
 125  *      /dev/watchdog handling
 126  */
 127
 128 static int sp5100_tco_open(struct inode *inode, struct file *file)
 129 {
 130         /* /dev/watchdog can only be opened once */
 131         if (test_and_set_bit(0, &timer_alive))
 132                 return -EBUSY;
 133
 134         /* Reload and activate timer */
 135         tco_timer_start();
 136         tco_timer_keepalive();
 137         return nonseekable_open(inode, file);
 138 }
 139
 140 static int sp5100_tco_release(struct inode *inode, struct file *file)
 141 {
 142         /* Shut off the timer. */
 143         if (tco_expect_close == 42) {
 144                 tco_timer_stop();
 145         } else {
 146                 printk(KERN_CRIT PFX
 147                         "Unexpected close, not stopping watchdog!\n");
 148                 tco_timer_keepalive();
 149         }
 150         clear_bit(0, &timer_alive);
 151         tco_expect_close = 0;
 152         return 0;
 153 }
 154
 155 static ssize_t sp5100_tco_write(struct file *file, const char __user *data,
 156                                 size_t len, loff_t *ppos)
 157 {
 158         /* See if we got the magic character 'V' and reload the timer */
 159         if (len) {
 160                 if (!nowayout) {
 161                         size_t i;
 162
 163                         /* note: just in case someone wrote the magic character
 164                          * five months ago... */
 165                         tco_expect_close = 0;
 166
 167                         /* scan to see whether or not we got the magic character
 168                          */
 169                         for (i = 0; i != len; i++) {
 170                                 char c;
 171                                 if (get_user(c, data + i))
 172                                         return -EFAULT;
 173                                 if (c == 'V')
 174                                         tco_expect_close = 42;
 175                         }
 176                 }
 177
 178                 /* someone wrote to us, we should reload the timer */
 179                 tco_timer_keepalive();
 180         }
 181         return len;
 182 }
 183
 184 static long sp5100_tco_ioctl(struct file *file, unsigned int cmd,
 185                              unsigned long arg)
 186 {
 187         int new_options, retval = -EINVAL;
 188         int new_heartbeat;
 189         void __user *argp = (void __user *)arg;
 190         int __user *p = argp;
 191         static const struct watchdog_info ident = {
 192                 .options =              WDIOF_SETTIMEOUT |
 193                                         WDIOF_KEEPALIVEPING |
 194                                         WDIOF_MAGICCLOSE,
 195                 .firmware_version =     0,
 196                 .identity =             TCO_MODULE_NAME,
 197         };
 198
 199         switch (cmd) {
 200         case WDIOC_GETSUPPORT:
 201                 return copy_to_user(argp, &ident,
 202                         sizeof(ident)) ? -EFAULT : 0;
 203         case WDIOC_GETSTATUS:
 204         case WDIOC_GETBOOTSTATUS:
 205                 return put_user(0, p);
 206         case WDIOC_SETOPTIONS:
 207                 if (get_user(new_options, p))
 208                         return -EFAULT;
 209                 if (new_options & WDIOS_DISABLECARD) {
 210                         tco_timer_stop();
 211                         retval = 0;
 212                 }
 213                 if (new_options & WDIOS_ENABLECARD) {
 214                         tco_timer_start();
 215                         tco_timer_keepalive();
 216                         retval = 0;
 217                 }
 218                 return retval;
 219         case WDIOC_KEEPALIVE:
 220                 tco_timer_keepalive();
 221                 return 0;
 222         case WDIOC_SETTIMEOUT:
 223                 if (get_user(new_heartbeat, p))
 224                         return -EFAULT;
 225                 if (tco_timer_set_heartbeat(new_heartbeat))
 226                         return -EINVAL;
 227                 tco_timer_keepalive();
 228                 /* Fall through */
 229         case WDIOC_GETTIMEOUT:
 230                 return put_user(heartbeat, p);
 231         default:
 232                 return -ENOTTY;
 233         }
 234 }
 235
 236 /*
 237  * Kernel Interfaces
 238  */
 239
 240 static const struct file_operations sp5100_tco_fops = {
 241         .owner =                THIS_MODULE,
 242         .llseek =               no_llseek,
 243         .write =                sp5100_tco_write,
 244         .unlocked_ioctl =       sp5100_tco_ioctl,
 245         .open =                 sp5100_tco_open,
 246         .release =              sp5100_tco_release,
 247 };
 248
 249 static struct miscdevice sp5100_tco_miscdev = {
 250         .minor =        WATCHDOG_MINOR,
 251         .name =         "watchdog",
 252         .fops =         &sp5100_tco_fops,
 253 };
 254
 255 /*
 256  * Data for PCI driver interface
 257  *
 258  * This data only exists for exporting the supported
 259  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 260  * register a pci_driver, because someone else might
 261  * want to register another driver on the same PCI id.
 262  */
 263 static DEFINE_PCI_DEVICE_TABLE(sp5100_tco_pci_tbl) = {
 264         { PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS, PCI_ANY_ID,
 265           PCI_ANY_ID, },
 266         { 0, },                 /* End of list */
 267 };
 268 MODULE_DEVICE_TABLE(pci, sp5100_tco_pci_tbl);
 269
 270 /*
 271  * Init & exit routines
 272  */
 273
 274 static unsigned char __devinit sp5100_tco_setupdevice(void)
 275 {
 276         struct pci_dev *dev = NULL;
 277         u32 val;
 278
 279         /* Match the PCI device */
 280         for_each_pci_dev(dev) {
 281                 if (pci_match_id(sp5100_tco_pci_tbl, dev) != NULL) {
 282                         sp5100_tco_pci = dev;
 283                         break;
 284                 }
 285         }
 286
 287         if (!sp5100_tco_pci)
 288                 return 0;
 289
 290         /* Request the IO ports used by this driver */
 291         pm_iobase = SP5100_IO_PM_INDEX_REG;
 292         if (!request_region(pm_iobase, SP5100_PM_IOPORTS_SIZE, "SP5100 TCO")) {
 293                 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
 294                         pm_iobase);
 295                 goto exit;
 296         }
 297
 298         /* Find the watchdog base address. */
 299         outb(SP5100_PM_WATCHDOG_BASE3, SP5100_IO_PM_INDEX_REG);
 300         val = inb(SP5100_IO_PM_DATA_REG);
 301         outb(SP5100_PM_WATCHDOG_BASE2, SP5100_IO_PM_INDEX_REG);
 302         val = val << 8 | inb(SP5100_IO_PM_DATA_REG);
 303         outb(SP5100_PM_WATCHDOG_BASE1, SP5100_IO_PM_INDEX_REG);
 304         val = val << 8 | inb(SP5100_IO_PM_DATA_REG);
 305         outb(SP5100_PM_WATCHDOG_BASE0, SP5100_IO_PM_INDEX_REG);
 306         /* Low three bits of BASE0 are reserved. */
 307         val = val << 8 | (inb(SP5100_IO_PM_DATA_REG) & 0xf8);
 308
 309         if (!request_mem_region_exclusive(val, SP5100_WDT_MEM_MAP_SIZE,
 310                                                                 "SP5100 TCO")) {
 311                 printk(KERN_ERR PFX "mmio address 0x%04x already in use\n",
 312                         val);
 313                 goto unreg_region;
 314         }
 315         tcobase_phys = val;
 316
 317         tcobase = ioremap(val, SP5100_WDT_MEM_MAP_SIZE);
 318         if (tcobase == 0) {
 319                 printk(KERN_ERR PFX "failed to get tcobase address\n");
 320                 goto unreg_mem_region;
 321         }
 322
 323         /* Enable watchdog decode bit */
 324         pci_read_config_dword(sp5100_tco_pci,
 325                               SP5100_PCI_WATCHDOG_MISC_REG,
 326                               &val);
 327
 328         val |= SP5100_PCI_WATCHDOG_DECODE_EN;
 329
 330         pci_write_config_dword(sp5100_tco_pci,
 331                                SP5100_PCI_WATCHDOG_MISC_REG,
 332                                val);
 333
 334         /* Enable Watchdog timer and set the resolution to 1 sec. */
 335         outb(SP5100_PM_WATCHDOG_CONTROL, SP5100_IO_PM_INDEX_REG);
 336         val = inb(SP5100_IO_PM_DATA_REG);
 337         val |= SP5100_PM_WATCHDOG_SECOND_RES;
 338         val &= ~SP5100_PM_WATCHDOG_DISABLE;
 339         outb(val, SP5100_IO_PM_DATA_REG);
 340
 341         /* Check that the watchdog action is set to reset the system. */
 342         val = readl(SP5100_WDT_CONTROL(tcobase));
 343         val &= ~SP5100_PM_WATCHDOG_ACTION_RESET;
 344         writel(val, SP5100_WDT_CONTROL(tcobase));
 345
 346         /* Set a reasonable heartbeat before we stop the timer */
 347         tco_timer_set_heartbeat(heartbeat);
 348
 349         /*
 350          * Stop the TCO before we change anything so we don't race with
 351          * a zeroed timer.
 352          */
 353         tco_timer_stop();
 354
 355         /* Done */
 356         return 1;
 357
 358 unreg_mem_region:
 359         release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
 360 unreg_region:
 361         release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
 362 exit:
 363         return 0;
 364 }
 365
 366 static int __devinit sp5100_tco_init(struct platform_device *dev)
 367 {
 368         int ret;
 369         u32 val;
 370
 371         /* Check whether or not the hardware watchdog is there. If found, then
 372          * set it up.
 373          */
 374         if (!sp5100_tco_setupdevice())
 375                 return -ENODEV;
 376
 377         /* Check to see if last reboot was due to watchdog timeout */
 378         printk(KERN_INFO PFX "Watchdog reboot %sdetected.\n",
 379                readl(SP5100_WDT_CONTROL(tcobase)) & SP5100_PM_WATCHDOG_FIRED ?
 380                       "" : "not ");
 381
 382         /* Clear out the old status */
 383         val = readl(SP5100_WDT_CONTROL(tcobase));
 384         val &= ~SP5100_PM_WATCHDOG_FIRED;
 385         writel(val, SP5100_WDT_CONTROL(tcobase));
 386
 387         /*
 388          * Check that the heartbeat value is within it's range.
 389          * If not, reset to the default.
 390          */
 391         if (tco_timer_set_heartbeat(heartbeat)) {
 392                 heartbeat = WATCHDOG_HEARTBEAT;
 393                 tco_timer_set_heartbeat(heartbeat);
 394         }
 395
 396         ret = misc_register(&sp5100_tco_miscdev);
 397         if (ret != 0) {
 398                 printk(KERN_ERR PFX "cannot register miscdev on minor="
 399                        "%d (err=%d)\n",
 400                        WATCHDOG_MINOR, ret);
 401                 goto exit;
 402         }
 403
 404         clear_bit(0, &timer_alive);
 405
 406         printk(KERN_INFO PFX "initialized (0x%p). heartbeat=%d sec"
 407                 " (nowayout=%d)\n",
 408                 tcobase, heartbeat, nowayout);
 409
 410         return 0;
 411
 412 exit:
 413         iounmap(tcobase);
 414         release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
 415         release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
 416         return ret;
 417 }
 418
 419 static void __devexit sp5100_tco_cleanup(void)
 420 {
 421         /* Stop the timer before we leave */
 422         if (!nowayout)
 423                 tco_timer_stop();
 424
 425         /* Deregister */
 426         misc_deregister(&sp5100_tco_miscdev);
 427         iounmap(tcobase);
 428         release_mem_region(tcobase_phys, SP5100_WDT_MEM_MAP_SIZE);
 429         release_region(pm_iobase, SP5100_PM_IOPORTS_SIZE);
 430 }
 431
 432 static int __devexit sp5100_tco_remove(struct platform_device *dev)
 433 {
 434         if (tcobase)
 435                 sp5100_tco_cleanup();
 436         return 0;
 437 }
 438
 439 static void sp5100_tco_shutdown(struct platform_device *dev)
 440 {
 441         tco_timer_stop();
 442 }
 443
 444 static struct platform_driver sp5100_tco_driver = {
 445         .probe          = sp5100_tco_init,
 446         .remove         = __devexit_p(sp5100_tco_remove),
 447         .shutdown       = sp5100_tco_shutdown,
 448         .driver         = {
 449                 .owner  = THIS_MODULE,
 450                 .name   = TCO_MODULE_NAME,
 451         },
 452 };
 453
 454 static int __init sp5100_tco_init_module(void)
 455 {
 456         int err;
 457
 458         printk(KERN_INFO PFX "SP5100 TCO WatchDog Timer Driver v%s\n",
 459                TCO_VERSION);
 460
 461         err = platform_driver_register(&sp5100_tco_driver);
 462         if (err)
 463                 return err;
 464
 465         sp5100_tco_platform_device = platform_device_register_simple(
 466                                         TCO_MODULE_NAME, -1, NULL, 0);
 467         if (IS_ERR(sp5100_tco_platform_device)) {
 468                 err = PTR_ERR(sp5100_tco_platform_device);
 469                 goto unreg_platform_driver;
 470         }
 471
 472         return 0;
 473
 474 unreg_platform_driver:
 475         platform_driver_unregister(&sp5100_tco_driver);
 476         return err;
 477 }
 478
 479 static void __exit sp5100_tco_cleanup_module(void)
 480 {
 481         platform_device_unregister(sp5100_tco_platform_device);
 482         platform_driver_unregister(&sp5100_tco_driver);
 483         printk(KERN_INFO PFX "SP5100 TCO Watchdog Module Unloaded.\n");
 484 }
 485
 486 module_init(sp5100_tco_init_module);
 487 module_exit(sp5100_tco_cleanup_module);
 488
 489 MODULE_AUTHOR("Priyanka Gupta");
 490 MODULE_DESCRIPTION("TCO timer driver for SP5100 chipset");
 491 MODULE_LICENSE("GPL");
 492 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);