target/linux/ubicom32/files/drivers/watchdog/ubi32_wdt.c

   1 /*
   2  * drivers/watchdog/ubi32_wdt.c
   3  *   Ubicom32 Watchdog Driver
   4  *
   5  * Originally based on softdog.c
   6  * Copyright 2006-2007 Analog Devices Inc.
   7  * Copyright 2006-2007 Michele d'Amico
   8  * Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
   9  * (C) Copyright 2009, Ubicom, Inc.
  10  *
  11  * This file is part of the Ubicom32 Linux Kernel Port.
  12  *
  13  * The Ubicom32 Linux Kernel Port is free software: you can redistribute
  14  * it and/or modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation, either version 2 of the
  16  * License, or (at your option) any later version.
  17  *
  18  * The Ubicom32 Linux Kernel Port is distributed in the hope that it
  19  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  20  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  21  * the GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with the Ubicom32 Linux Kernel Port.  If not,
  25  * see <http://www.gnu.org/licenses/>.
  26  *
  27  * Ubicom32 implementation derived from (with many thanks):
  28  *   arch/m68knommu
  29  *   arch/blackfin
  30  *   arch/parisc
  31  */
  32 #include <linux/platform_device.h>
  33 #include <linux/module.h>
  34 #include <linux/moduleparam.h>
  35 #include <linux/types.h>
  36 #include <linux/timer.h>
  37 #include <linux/miscdevice.h>
  38 #include <linux/watchdog.h>
  39 #include <linux/fs.h>
  40 #include <linux/notifier.h>
  41 #include <linux/reboot.h>
  42 #include <linux/init.h>
  43 #include <linux/interrupt.h>
  44 #include <linux/uaccess.h>
  45 #include <asm/ip5000.h>
  46
  47 #define WATCHDOG_NAME "ubi32-wdt"
  48 #define PFX WATCHDOG_NAME ": "
  49
  50 #define OSC1_FREQ 12000000
  51 #define WATCHDOG_SEC_TO_CYC(x) (OSC1_FREQ * (x))
  52 #define WATCHDOG_MAX_SEC (0xffffffff / OSC1_FREQ)
  53
  54 #define MIN_PROCESSOR_ADDRESS 0x03000000
  55
  56 static DEFINE_SPINLOCK(ubi32_wdt_spinlock);
  57
  58 #define WATCHDOG_TIMEOUT 20
  59
  60 #if defined(CONFIG_WATCHDOG_NOWAYOUT)
  61 #define WATCHDOG_NOWAYOUT 1
  62 #else
  63 #define WATCHDOG_NOWAYOUT 0
  64 #endif
  65
  66 static unsigned int timeout = WATCHDOG_TIMEOUT;
  67 static int nowayout = WATCHDOG_NOWAYOUT;
  68 static struct watchdog_info ubi32_wdt_info;
  69 static unsigned long open_check;
  70 static char expect_close;
  71
  72 #if !defined(CONFIG_SMP)
  73 #define UBI32_WDT_LOCK(lock, flags) local_irq_save(flags)
  74 #define UBI32_WDT_UNLOCK(lock, flags) local_irq_restore(flags)
  75 #define UBI32_WDT_LOCK_CHECK()
  76 #else
  77 #define UBI32_WDT_LOCK(lock, flags) spin_lock_irqsave((lock), (flags));
  78 #define UBI32_WDT_UNLOCK(lock, flags) spin_unlock_irqrestore((lock), (flags));
  79 #define UBI32_WDT_LOCK_CHECK() BUG_ON(!spin_is_locked(&ubi32_wdt_spinlock));
  80 #endif
  81
  82 /*
  83  * ubi32_wdt_remaining()
  84  *      Return the approximate number of seconds remaining
  85  */
  86 static int ubi32_wdt_remaining(void)
  87 {
  88         int compare;
  89         int curr;
  90
  91         UBI32_WDT_LOCK_CHECK();
  92
  93         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
  94         compare = ubicom32_read_reg(&UBICOM32_IO_TIMER->wdcom);
  95         curr = ubicom32_read_reg(&UBICOM32_IO_TIMER->mptval);
  96         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
  97         return (compare - curr) / OSC1_FREQ;
  98
  99 }
 100
 101 /*
 102  * ubi32_wdt_keepalive()
 103  *      Keep the Userspace Watchdog Alive
 104  *
 105  * The Userspace watchdog got a KeepAlive: schedule the next timeout.
 106  */
 107 static int ubi32_wdt_keepalive(void)
 108 {
 109         UBI32_WDT_LOCK_CHECK();
 110         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
 111         ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcom,
 112                         ubicom32_read_reg(&UBICOM32_IO_TIMER->mptval)
 113                         + WATCHDOG_SEC_TO_CYC(timeout));
 114         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
 115         return 0;
 116 }
 117
 118 /*
 119  * ubi32_wdt_stop()
 120  *      Stop the on-chip Watchdog
 121  */
 122 static int ubi32_wdt_stop(void)
 123 {
 124         UBI32_WDT_LOCK_CHECK();
 125         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
 126         ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcfg, TIMER_WATCHDOG_DISABLE);
 127         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
 128         return 0;
 129 }
 130
 131 /*
 132  * ubi32_wdt_start()
 133  *      Start the on-chip Watchdog
 134  */
 135 static int ubi32_wdt_start(void)
 136 {
 137         UBI32_WDT_LOCK_CHECK();
 138         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
 139         ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcom,
 140                         ubicom32_read_reg(&UBICOM32_IO_TIMER->mptval)
 141                         + WATCHDOG_SEC_TO_CYC(timeout));
 142         ubicom32_write_reg(&UBICOM32_IO_TIMER->wdcfg, ~TIMER_WATCHDOG_DISABLE);
 143         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
 144         return 0;
 145 }
 146
 147 /*
 148  * ubi32_wdt_running()
 149  *      Return true if the watchdog is configured
 150  */
 151 static int ubi32_wdt_running(void)
 152 {
 153         int enabled;
 154
 155         UBI32_WDT_LOCK_CHECK();
 156         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, TIMER_TKEYVAL);
 157         enabled = ubicom32_read_reg(&UBICOM32_IO_TIMER->wdcfg) == ~TIMER_WATCHDOG_DISABLE;
 158         ubicom32_write_reg(&UBICOM32_IO_TIMER->tkey, 0);
 159         return enabled;
 160 }
 161
 162 /*
 163  * ubi32_wdt_set_timeout()
 164  *      Set the Userspace Watchdog timeout
 165  *
 166  * - @t: new timeout value (in seconds)
 167  */
 168 static int ubi32_wdt_set_timeout(unsigned long t)
 169 {
 170         UBI32_WDT_LOCK_CHECK();
 171
 172         if (t > WATCHDOG_MAX_SEC) {
 173                 printk(KERN_WARNING PFX "request to large: %ld [1-%d] sec)\n", t, WATCHDOG_MAX_SEC);
 174                 return -EINVAL;
 175         }
 176
 177         /*
 178          * If we are running, then reset the time value so
 179          * that the new value has an immediate effect.
 180          */
 181         timeout = t;
 182         if (ubi32_wdt_running()) {
 183                 ubi32_wdt_keepalive();
 184         }
 185         return 0;
 186 }
 187
 188 /*
 189  * ubi32_wdt_open()
 190  *      Open the Device
 191  */
 192 static int ubi32_wdt_open(struct inode *inode, struct file *file)
 193 {
 194         unsigned long flags;
 195
 196         if (test_and_set_bit(0, &open_check))
 197                 return -EBUSY;
 198
 199         if (nowayout)
 200                 __module_get(THIS_MODULE);
 201
 202         spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 203         ubi32_wdt_start();
 204         spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 205
 206         return nonseekable_open(inode, file);
 207 }
 208
 209 /*
 210  * ubi32_wdt_close()
 211  *      Close the Device
 212  */
 213 static int ubi32_wdt_release(struct inode *inode, struct file *file)
 214 {
 215         unsigned long flags;
 216
 217         /*
 218          * If we don't expect a close, then the watchdog continues
 219          * even though the device is closed.  The caller will have
 220          * a full timeout value to reopen the device and continue
 221          * stroking it.
 222          */
 223         if (expect_close != 42) {
 224                 printk(KERN_CRIT PFX
 225                         "Unexpected close, not stopping watchdog!\n");
 226                 spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 227                 ubi32_wdt_keepalive();
 228                 spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 229         } else {
 230                 spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 231                 ubi32_wdt_stop();
 232                 spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 233         }
 234
 235         expect_close = 0;
 236         clear_bit(0, &open_check);
 237         return 0;
 238 }
 239
 240 /*
 241  * ubi32_wdt_write()
 242  *      Write to Device
 243  *
 244  * If the user writes nothing, nothing happens.
 245  * If the user writes a V, then we expect a close and allow a release.
 246  * If the user writes anything else, it is ignored.
 247  */
 248 static ssize_t ubi32_wdt_write(struct file *file, const char __user *data,
 249                                                 size_t len, loff_t *ppos)
 250 {
 251         size_t i;
 252         unsigned long flags;
 253
 254         /*
 255          * Every write resets the expect_close.  The last write
 256          * must be a V to allow shutdown on close.
 257          */
 258         expect_close = 0;
 259
 260         /*
 261          * Empty writes still ping.
 262          */
 263         if (!len) {
 264                 goto ping;
 265         }
 266
 267         /*
 268          * If nowayout is set, it does not matter if the caller
 269          * is trying to send the magic 'V' we will not allow a
 270          * close to stop us.
 271          */
 272         if (nowayout) {
 273                 goto ping;
 274         }
 275
 276         /*
 277          * See if the program wrote a 'V' and if so disable
 278          * the watchdog on release.
 279          */
 280         for (i = 0; i < len; i++) {
 281                 char c;
 282                 if (get_user(c, data + i)) {
 283                         return -EFAULT;
 284                 }
 285
 286                 if (c == 'V') {
 287                         expect_close = 42;
 288                 }
 289         }
 290
 291 ping:
 292         spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 293         ubi32_wdt_keepalive();
 294         spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 295         return len;
 296 }
 297
 298 /*
 299  * ubi32_wdt_ioctl()
 300  *      Query the watchdog device.
 301  *
 302  * Query basic information from the device or ping it, as outlined by the
 303  * watchdog API.
 304  */
 305 static long ubi32_wdt_ioctl(struct file *file,
 306                                 unsigned int cmd, unsigned long arg)
 307 {
 308         void __user *argp = (void __user *)arg;
 309         int __user *p = argp;
 310
 311         switch (cmd) {
 312         case WDIOC_GETSUPPORT:
 313                 if (copy_to_user(argp, &ubi32_wdt_info, sizeof(ubi32_wdt_info))) {
 314                         return -EFAULT;
 315                 }
 316                 return 0;
 317
 318         case WDIOC_GETSTATUS: {
 319                 unsigned long flags;
 320                 int running;
 321
 322                 spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 323                 running = ubi32_wdt_running();
 324                 spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 325                 return running;
 326         }
 327
 328         case WDIOC_GETBOOTSTATUS:
 329                 return ubicom32_get_reset_reason();
 330
 331         case WDIOC_SETOPTIONS: {
 332                 unsigned long flags;
 333                 int options, ret = -EINVAL;
 334
 335                 /*
 336                  * The sample application does not pass a pointer
 337                  * but directly passes a value of 1 or 2; however
 338                  * all of the implementations (and thus probably
 339                  * the real applications) pass a pointer to a value.
 340                  *
 341                  * It should be noted that  WDIOC_SETOPTIONS is defined as
 342                  * _IOR(WATCHDOG_IOCTL_BASE, 4, int), which means
 343                  * that it should be an int and NOT a pointer.
 344                  *
 345                  * TODO: Examine this code for future chips.
 346                  * TODO: Report the sample code defect.
 347                  */
 348                 if ((int)p < MIN_PROCESSOR_ADDRESS) {
 349                         options = (int)p;
 350                 } else {
 351                         if (get_user(options, p))
 352                         return -EFAULT;
 353                 }
 354
 355                 spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 356                 if (options & WDIOS_DISABLECARD) {
 357                         ubi32_wdt_stop();
 358                         ret = 0;
 359                 }
 360                 if (options & WDIOS_ENABLECARD) {
 361                         ubi32_wdt_start();
 362                         ret = 0;
 363                 }
 364                 spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 365                 return ret;
 366         }
 367
 368         case WDIOC_KEEPALIVE: {
 369                 unsigned long flags;
 370
 371                 spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 372                 ubi32_wdt_keepalive();
 373                 spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 374                 return 0;
 375         }
 376
 377         case WDIOC_SETTIMEOUT: {
 378                 int new_timeout;
 379                 unsigned long flags;
 380                 int ret  = 0;
 381
 382                 if (get_user(new_timeout, p))
 383                         return -EFAULT;
 384
 385                 spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 386                 ret = ubi32_wdt_set_timeout(new_timeout);
 387                 spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 388                 return ret;
 389
 390         }
 391
 392         case WDIOC_GETTIMEOUT:
 393                 return put_user(timeout, p);
 394
 395         case WDIOC_GETTIMELEFT: {
 396                 unsigned long flags;
 397                 int remaining = 0;
 398
 399                 spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 400                 remaining = ubi32_wdt_remaining();
 401                 spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 402                 return put_user(remaining, p);
 403         }
 404
 405         default:
 406                 return -ENOTTY;
 407         }
 408 }
 409
 410 /*
 411  * ubi32_wdt_notify_sys()
 412  *      Notification callback function for system events.
 413  *
 414  * Turn off the watchdog during a SYS_DOWN or SYS_HALT.
 415  */
 416 static int ubi32_wdt_notify_sys(struct notifier_block *this,
 417                                         unsigned long code, void *unused)
 418 {
 419         if (code == SYS_DOWN || code == SYS_HALT) {
 420                 unsigned long flags;
 421
 422                 spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 423                 ubi32_wdt_stop();
 424                 spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 425         }
 426
 427         return NOTIFY_DONE;
 428 }
 429
 430 #ifdef CONFIG_PM
 431 static int state_before_suspend;
 432
 433 /*
 434  * ubi32_wdt_suspend()
 435  *      suspend the watchdog
 436  *
 437  * Remember if the watchdog was running and stop it.
 438  */
 439 static int ubi32_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 440 {
 441         unsigned long flags;
 442         spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 443         state_before_suspend = ubi32_wdt_running();
 444         ubi32_wdt_stop();
 445         spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 446
 447         return 0;
 448 }
 449
 450 /*
 451  * ubi32_wdt_resume()
 452  *      Resume the watchdog
 453  *
 454  * If the watchdog was running, turn it back on.
 455  */
 456 static int ubi32_wdt_resume(struct platform_device *pdev)
 457 {
 458         if (state_before_suspend) {
 459                 unsigned long flags;
 460                 spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 461                 ubi32_wdt_set_timeout(timeout);
 462                 ubi32_wdt_start();
 463                 spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 464         }
 465
 466         return 0;
 467 }
 468 #else
 469 # define ubi32_wdt_suspend NULL
 470 # define ubi32_wdt_resume NULL
 471 #endif
 472
 473 static const struct file_operations ubi32_wdt_fops = {
 474         .owner          = THIS_MODULE,
 475         .llseek         = no_llseek,
 476         .write          = ubi32_wdt_write,
 477         .unlocked_ioctl = ubi32_wdt_ioctl,
 478         .open           = ubi32_wdt_open,
 479         .release        = ubi32_wdt_release,
 480 };
 481
 482 static struct miscdevice ubi32_wdt_miscdev = {
 483         .minor    = WATCHDOG_MINOR,
 484         .name     = "watchdog",
 485         .fops     = &ubi32_wdt_fops,
 486 };
 487
 488 static struct watchdog_info ubi32_wdt_info = {
 489         .identity = "Ubicom32 Watchdog",
 490         .options  = WDIOF_SETTIMEOUT |
 491                     WDIOF_KEEPALIVEPING |
 492                     WDIOF_MAGICCLOSE,
 493 };
 494
 495 static struct notifier_block ubi32_wdt_notifier = {
 496         .notifier_call = ubi32_wdt_notify_sys,
 497 };
 498
 499 /*
 500  * ubi32_wdt_probe()
 501  *      Probe/register the watchdog module
 502  *
 503  * Registers the misc device and notifier handler.  Actual device
 504  * initialization is handled by ubi32_wdt_open().
 505  */
 506 static int __devinit ubi32_wdt_probe(struct platform_device *pdev)
 507 {
 508         int ret;
 509
 510         ret = register_reboot_notifier(&ubi32_wdt_notifier);
 511         if (ret) {
 512                 printk(KERN_ERR PFX
 513                         "cannot register reboot notifier (err=%d)\n", ret);
 514                 return ret;
 515         }
 516
 517         ret = misc_register(&ubi32_wdt_miscdev);
 518         if (ret) {
 519                 printk(KERN_ERR PFX
 520                         "cannot register miscdev on minor=%d (err=%d)\n",
 521                                 WATCHDOG_MINOR, ret);
 522                 unregister_reboot_notifier(&ubi32_wdt_notifier);
 523                 return ret;
 524         }
 525
 526         printk(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
 527                timeout, nowayout);
 528
 529         return 0;
 530 }
 531
 532 /*
 533  * ubi32_wdt_remove()
 534  *      Uninstall the module
 535  *
 536  * Unregisters the misc device and notifier handler.  Actual device
 537  * deinitialization is handled by ubi32_wdt_close().
 538  */
 539 static int __devexit ubi32_wdt_remove(struct platform_device *pdev)
 540 {
 541         misc_deregister(&ubi32_wdt_miscdev);
 542         unregister_reboot_notifier(&ubi32_wdt_notifier);
 543         return 0;
 544 }
 545
 546 static struct platform_device *ubi32_wdt_device;
 547
 548 static struct platform_driver ubi32_wdt_driver = {
 549         .probe     = ubi32_wdt_probe,
 550         .remove    = __devexit_p(ubi32_wdt_remove),
 551         .suspend   = ubi32_wdt_suspend,
 552         .resume    = ubi32_wdt_resume,
 553         .driver    = {
 554                 .name  = WATCHDOG_NAME,
 555                 .owner = THIS_MODULE,
 556         },
 557 };
 558
 559 /*
 560  * ubi32_wdt_init()
 561  *      Initialize the watchdog.
 562  *
 563  * Checks the module params and registers the platform device & driver.
 564  * Real work is in the platform probe function.
 565  */
 566 static int __init ubi32_wdt_init(void)
 567 {
 568         unsigned long flags;
 569         int ret;
 570
 571         /*
 572          * Check that the timeout value is within range
 573          */
 574         spin_lock_irqsave(&ubi32_wdt_spinlock, flags);
 575         ret = ubi32_wdt_set_timeout(timeout);
 576         spin_unlock_irqrestore(&ubi32_wdt_spinlock, flags);
 577         if (ret) {
 578                 return ret;
 579         }
 580
 581         /*
 582          * Since this is an on-chip device and needs no board-specific
 583          * resources, we'll handle all the platform device stuff here.
 584          */
 585         ret = platform_driver_register(&ubi32_wdt_driver);
 586         if (ret) {
 587                 printk(KERN_ERR PFX "unable to register driver\n");
 588                 return ret;
 589         }
 590
 591         ubi32_wdt_device = platform_device_register_simple(WATCHDOG_NAME, -1, NULL, 0);
 592         if (IS_ERR(ubi32_wdt_device)) {
 593                 printk(KERN_ERR PFX "unable to register device\n");
 594                 platform_driver_unregister(&ubi32_wdt_driver);
 595                 return PTR_ERR(ubi32_wdt_device);
 596         }
 597
 598         return 0;
 599 }
 600
 601 /*
 602  * ubi32_wdt_exit()
 603  *      Deinitialize module
 604  *
 605  * Back out the platform device & driver steps.  Real work is in the
 606  * platform remove function.
 607  */
 608 static void __exit ubi32_wdt_exit(void)
 609 {
 610         platform_device_unregister(ubi32_wdt_device);
 611         platform_driver_unregister(&ubi32_wdt_driver);
 612 }
 613
 614 module_init(ubi32_wdt_init);
 615 module_exit(ubi32_wdt_exit);
 616
 617 MODULE_AUTHOR("Sol Kavy<sol@ubicom.com>");
 618 MODULE_DESCRIPTION("Ubicom32 Watchdog Device Driver");
 619 MODULE_LICENSE("GPL");
 620 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 621
 622 module_param(timeout, uint, 0);
 623 MODULE_PARM_DESC(timeout,
 624         "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
 625                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
 626
 627 module_param(nowayout, int, 0);
 628 MODULE_PARM_DESC(nowayout,
 629         "Watchdog cannot be stopped once started (default="
 630                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");