drivers/watchdog/intel_scu_watchdog.c

   1 /*
   2  *      Intel_SCU 0.2:  An Intel SCU IOH Based Watchdog Device
   3  *                      for Intel part #(s):
   4  *                              - AF82MP20 PCH
   5  *
   6  *      Copyright (C) 2009-2010 Intel Corporation. All rights reserved.
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of version 2 of the GNU General
  10  *      Public License as published by the Free Software Foundation.
  11  *
  12  *      This program is distributed in the hope that it will be
  13  *      useful, but WITHOUT ANY WARRANTY; without even the implied
  14  *      warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  15  *      PURPOSE.  See the GNU General Public License for more details.
  16  *      You should have received a copy of the GNU General Public
  17  *      License along with this program; if not, write to the Free
  18  *      Software Foundation, Inc., 59 Temple Place - Suite 330,
  19  *      Boston, MA  02111-1307, USA.
  20  *      The full GNU General Public License is included in this
  21  *      distribution in the file called COPYING.
  22  *
  23  */
  24
  25 #include <linux/compiler.h>
  26 #include <linux/module.h>
  27 #include <linux/kernel.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/types.h>
  30 #include <linux/miscdevice.h>
  31 #include <linux/watchdog.h>
  32 #include <linux/fs.h>
  33 #include <linux/notifier.h>
  34 #include <linux/reboot.h>
  35 #include <linux/init.h>
  36 #include <linux/jiffies.h>
  37 #include <linux/uaccess.h>
  38 #include <linux/slab.h>
  39 #include <linux/io.h>
  40 #include <linux/interrupt.h>
  41 #include <linux/delay.h>
  42 #include <linux/sched.h>
  43 #include <linux/signal.h>
  44 #include <linux/sfi.h>
  45 #include <asm/irq.h>
  46 #include <asm/atomic.h>
  47 #include <asm/intel_scu_ipc.h>
  48 #include <asm/apb_timer.h>
  49 #include <asm/mrst.h>
  50
  51 #include "intel_scu_watchdog.h"
  52
  53 /* Bounds number of times we will retry loading time count */
  54 /* This retry is a work around for a silicon bug.          */
  55 #define MAX_RETRY 16
  56
  57 #define IPC_SET_WATCHDOG_TIMER  0xF8
  58
  59 static int timer_margin = DEFAULT_SOFT_TO_HARD_MARGIN;
  60 module_param(timer_margin, int, 0);
  61 MODULE_PARM_DESC(timer_margin,
  62                 "Watchdog timer margin"
  63                 "Time between interrupt and resetting the system"
  64                 "The range is from 1 to 160"
  65                 "This is the time for all keep alives to arrive");
  66
  67 static int timer_set = DEFAULT_TIME;
  68 module_param(timer_set, int, 0);
  69 MODULE_PARM_DESC(timer_set,
  70                 "Default Watchdog timer setting"
  71                 "Complete cycle time"
  72                 "The range is from 1 to 170"
  73                 "This is the time for all keep alives to arrive");
  74
  75 /* After watchdog device is closed, check force_boot. If:
  76  * force_boot == 0, then force boot on next watchdog interrupt after close,
  77  * force_boot == 1, then force boot immediately when device is closed.
  78  */
  79 static int force_boot;
  80 module_param(force_boot, int, 0);
  81 MODULE_PARM_DESC(force_boot,
  82                 "A value of 1 means that the driver will reboot"
  83                 "the system immediately if the /dev/watchdog device is closed"
  84                 "A value of 0 means that when /dev/watchdog device is closed"
  85                 "the watchdog timer will be refreshed for one more interval"
  86                 "of length: timer_set. At the end of this interval, the"
  87                 "watchdog timer will reset the system."
  88                 );
  89
  90 /* there is only one device in the system now; this can be made into
  91  * an array in the future if we have more than one device */
  92
  93 static struct intel_scu_watchdog_dev watchdog_device;
  94
  95 /* Forces restart, if force_reboot is set */
  96 static void watchdog_fire(void)
  97 {
  98         if (force_boot) {
  99                 printk(KERN_CRIT PFX "Initiating system reboot.\n");
 100                 emergency_restart();
 101                 printk(KERN_CRIT PFX "Reboot didn't ?????\n");
 102         }
 103
 104         else {
 105                 printk(KERN_CRIT PFX "Immediate Reboot Disabled\n");
 106                 printk(KERN_CRIT PFX
 107                         "System will reset when watchdog timer times out!\n");
 108         }
 109 }
 110
 111 static int check_timer_margin(int new_margin)
 112 {
 113         if ((new_margin < MIN_TIME_CYCLE) ||
 114             (new_margin > MAX_TIME - timer_set)) {
 115                 pr_debug("Watchdog timer: value of new_margin %d is out of the range %d to %d\n",
 116                           new_margin, MIN_TIME_CYCLE, MAX_TIME - timer_set);
 117                 return -EINVAL;
 118         }
 119         return 0;
 120 }
 121
 122 /*
 123  * IPC operations
 124  */
 125 static int watchdog_set_ipc(int soft_threshold, int threshold)
 126 {
 127         u32     *ipc_wbuf;
 128         u8       cbuf[16] = { '\0' };
 129         int      ipc_ret = 0;
 130
 131         ipc_wbuf = (u32 *)&cbuf;
 132         ipc_wbuf[0] = soft_threshold;
 133         ipc_wbuf[1] = threshold;
 134
 135         ipc_ret = intel_scu_ipc_command(
 136                         IPC_SET_WATCHDOG_TIMER,
 137                         0,
 138                         ipc_wbuf,
 139                         2,
 140                         NULL,
 141                         0);
 142
 143         if (ipc_ret != 0)
 144                 pr_err("Error setting SCU watchdog timer: %x\n", ipc_ret);
 145
 146         return ipc_ret;
 147 };
 148
 149 /*
 150  *      Intel_SCU operations
 151  */
 152
 153 /* timer interrupt handler */
 154 static irqreturn_t watchdog_timer_interrupt(int irq, void *dev_id)
 155 {
 156         int int_status;
 157         int_status = ioread32(watchdog_device.timer_interrupt_status_addr);
 158
 159         pr_debug("Watchdog timer: irq, int_status: %x\n", int_status);
 160
 161         if (int_status != 0)
 162                 return IRQ_NONE;
 163
 164         /* has the timer been started? If not, then this is spurious */
 165         if (watchdog_device.timer_started == 0) {
 166                 pr_debug("Watchdog timer: spurious interrupt received\n");
 167                 return IRQ_HANDLED;
 168         }
 169
 170         /* temporarily disable the timer */
 171         iowrite32(0x00000002, watchdog_device.timer_control_addr);
 172
 173         /* set the timer to the threshold */
 174         iowrite32(watchdog_device.threshold,
 175                   watchdog_device.timer_load_count_addr);
 176
 177         /* allow the timer to run */
 178         iowrite32(0x00000003, watchdog_device.timer_control_addr);
 179
 180         return IRQ_HANDLED;
 181 }
 182
 183 static int intel_scu_keepalive(void)
 184 {
 185
 186         /* read eoi register - clears interrupt */
 187         ioread32(watchdog_device.timer_clear_interrupt_addr);
 188
 189         /* temporarily disable the timer */
 190         iowrite32(0x00000002, watchdog_device.timer_control_addr);
 191
 192         /* set the timer to the soft_threshold */
 193         iowrite32(watchdog_device.soft_threshold,
 194                   watchdog_device.timer_load_count_addr);
 195
 196         /* allow the timer to run */
 197         iowrite32(0x00000003, watchdog_device.timer_control_addr);
 198
 199         return 0;
 200 }
 201
 202 static int intel_scu_stop(void)
 203 {
 204         iowrite32(0, watchdog_device.timer_control_addr);
 205         return 0;
 206 }
 207
 208 static int intel_scu_set_heartbeat(u32 t)
 209 {
 210         int                      ipc_ret;
 211         int                      retry_count;
 212         u32                      soft_value;
 213         u32                      hw_pre_value;
 214         u32                      hw_value;
 215
 216         watchdog_device.timer_set = t;
 217         watchdog_device.threshold =
 218                 timer_margin * watchdog_device.timer_tbl_ptr->freq_hz;
 219         watchdog_device.soft_threshold =
 220                 (watchdog_device.timer_set - timer_margin)
 221                 * watchdog_device.timer_tbl_ptr->freq_hz;
 222
 223         pr_debug("Watchdog timer: set_heartbeat: timer freq is %d\n",
 224                 watchdog_device.timer_tbl_ptr->freq_hz);
 225         pr_debug("Watchdog timer: set_heartbeat: timer_set is %x (hex)\n",
 226                 watchdog_device.timer_set);
 227         pr_debug("Watchdog timer: set_hearbeat: timer_margin is %x (hex)\n",
 228                 timer_margin);
 229         pr_debug("Watchdog timer: set_heartbeat: threshold is %x (hex)\n",
 230                 watchdog_device.threshold);
 231         pr_debug("Watchdog timer: set_heartbeat: soft_threshold is %x (hex)\n",
 232                 watchdog_device.soft_threshold);
 233
 234         /* Adjust thresholds by FREQ_ADJUSTMENT factor, to make the */
 235         /* watchdog timing come out right. */
 236         watchdog_device.threshold =
 237                 watchdog_device.threshold / FREQ_ADJUSTMENT;
 238         watchdog_device.soft_threshold =
 239                 watchdog_device.soft_threshold / FREQ_ADJUSTMENT;
 240
 241         /* temporarily disable the timer */
 242         iowrite32(0x00000002, watchdog_device.timer_control_addr);
 243
 244         /* send the threshold and soft_threshold via IPC to the processor */
 245         ipc_ret = watchdog_set_ipc(watchdog_device.soft_threshold,
 246                                    watchdog_device.threshold);
 247
 248         if (ipc_ret != 0) {
 249                 /* Make sure the watchdog timer is stopped */
 250                 intel_scu_stop();
 251                 return ipc_ret;
 252         }
 253
 254         /* Soft Threshold set loop. Early versions of silicon did */
 255         /* not always set this count correctly.  This loop checks */
 256         /* the value and retries if it was not set correctly.     */
 257
 258         retry_count = 0;
 259         soft_value = watchdog_device.soft_threshold & 0xFFFF0000;
 260         do {
 261
 262                 /* Make sure timer is stopped */
 263                 intel_scu_stop();
 264
 265                 if (MAX_RETRY < retry_count++) {
 266                         /* Unable to set timer value */
 267                         pr_err("Watchdog timer: Unable to set timer\n");
 268                         return -ENODEV;
 269                 }
 270
 271                 /* set the timer to the soft threshold */
 272                 iowrite32(watchdog_device.soft_threshold,
 273                         watchdog_device.timer_load_count_addr);
 274
 275                 /* read count value before starting timer */
 276                 hw_pre_value = ioread32(watchdog_device.timer_load_count_addr);
 277                 hw_pre_value = hw_pre_value & 0xFFFF0000;
 278
 279                 /* Start the timer */
 280                 iowrite32(0x00000003, watchdog_device.timer_control_addr);
 281
 282                 /* read the value the time loaded into its count reg */
 283                 hw_value = ioread32(watchdog_device.timer_load_count_addr);
 284                 hw_value = hw_value & 0xFFFF0000;
 285
 286
 287         } while (soft_value != hw_value);
 288
 289         watchdog_device.timer_started = 1;
 290
 291         return 0;
 292 }
 293
 294 /*
 295  * /dev/watchdog handling
 296  */
 297
 298 static int intel_scu_open(struct inode *inode, struct file *file)
 299 {
 300
 301         /* Set flag to indicate that watchdog device is open */
 302         if (test_and_set_bit(0, &watchdog_device.driver_open))
 303                 return -EBUSY;
 304
 305         /* Check for reopen of driver. Reopens are not allowed */
 306         if (watchdog_device.driver_closed)
 307                 return -EPERM;
 308
 309         return nonseekable_open(inode, file);
 310 }
 311
 312 static int intel_scu_release(struct inode *inode, struct file *file)
 313 {
 314         /*
 315          * This watchdog should not be closed, after the timer
 316          * is started with the WDIPC_SETTIMEOUT ioctl
 317          * If force_boot is set watchdog_fire() will cause an
 318          * immediate reset. If force_boot is not set, the watchdog
 319          * timer is refreshed for one more interval. At the end
 320          * of that interval, the watchdog timer will reset the system.
 321          */
 322
 323         if (!test_and_clear_bit(0, &watchdog_device.driver_open)) {
 324                 pr_debug("Watchdog timer: intel_scu_release, without open\n");
 325                 return -ENOTTY;
 326         }
 327
 328         if (!watchdog_device.timer_started) {
 329                 /* Just close, since timer has not been started */
 330                 pr_debug("Watchdog timer: closed, without starting timer\n");
 331                 return 0;
 332         }
 333
 334         printk(KERN_CRIT PFX
 335                "Unexpected close of /dev/watchdog!\n");
 336
 337         /* Since the timer was started, prevent future reopens */
 338         watchdog_device.driver_closed = 1;
 339
 340         /* Refresh the timer for one more interval */
 341         intel_scu_keepalive();
 342
 343         /* Reboot system (if force_boot is set) */
 344         watchdog_fire();
 345
 346         /* We should only reach this point if force_boot is not set */
 347         return 0;
 348 }
 349
 350 static ssize_t intel_scu_write(struct file *file,
 351                               char const *data,
 352                               size_t len,
 353                               loff_t *ppos)
 354 {
 355
 356         if (watchdog_device.timer_started)
 357                 /* Watchdog already started, keep it alive */
 358                 intel_scu_keepalive();
 359         else
 360                 /* Start watchdog with timer value set by init */
 361                 intel_scu_set_heartbeat(watchdog_device.timer_set);
 362
 363         return len;
 364 }
 365
 366 static long intel_scu_ioctl(struct file *file,
 367                            unsigned int cmd,
 368                            unsigned long arg)
 369 {
 370         void __user *argp = (void __user *)arg;
 371         u32 __user *p = argp;
 372         u32 new_margin;
 373
 374
 375         static const struct watchdog_info ident = {
 376                 .options =          WDIOF_SETTIMEOUT
 377                                     | WDIOF_KEEPALIVEPING,
 378                 .firmware_version = 0,  /* @todo Get from SCU via
 379                                                  ipc_get_scu_fw_version()? */
 380                 .identity =         "Intel_SCU IOH Watchdog"  /* len < 32 */
 381         };
 382
 383         switch (cmd) {
 384         case WDIOC_GETSUPPORT:
 385                 return copy_to_user(argp,
 386                                     &ident,
 387                                     sizeof(ident)) ? -EFAULT : 0;
 388         case WDIOC_GETSTATUS:
 389         case WDIOC_GETBOOTSTATUS:
 390                 return put_user(0, p);
 391         case WDIOC_KEEPALIVE:
 392                 intel_scu_keepalive();
 393
 394                 return 0;
 395         case WDIOC_SETTIMEOUT:
 396                 if (get_user(new_margin, p))
 397                         return -EFAULT;
 398
 399                 if (check_timer_margin(new_margin))
 400                         return -EINVAL;
 401
 402                 if (intel_scu_set_heartbeat(new_margin))
 403                         return -EINVAL;
 404                 return 0;
 405         case WDIOC_GETTIMEOUT:
 406                 return put_user(watchdog_device.soft_threshold, p);
 407
 408         default:
 409                 return -ENOTTY;
 410         }
 411 }
 412
 413 /*
 414  *      Notifier for system down
 415  */
 416 static int intel_scu_notify_sys(struct notifier_block *this,
 417                                unsigned long code,
 418                                void *another_unused)
 419 {
 420         if (code == SYS_DOWN || code == SYS_HALT)
 421                 /* Turn off the watchdog timer. */
 422                 intel_scu_stop();
 423         return NOTIFY_DONE;
 424 }
 425
 426 /*
 427  *      Kernel Interfaces
 428  */
 429 static const struct file_operations intel_scu_fops = {
 430         .owner          = THIS_MODULE,
 431         .llseek         = no_llseek,
 432         .write          = intel_scu_write,
 433         .unlocked_ioctl = intel_scu_ioctl,
 434         .open           = intel_scu_open,
 435         .release        = intel_scu_release,
 436 };
 437
 438 static int __init intel_scu_watchdog_init(void)
 439 {
 440         int ret;
 441         u32 __iomem *tmp_addr;
 442
 443         /*
 444          * We don't really need to check this as the SFI timer get will fail
 445          * but if we do so we can exit with a clearer reason and no noise.
 446          *
 447          * If it isn't an intel MID device then it doesn't have this watchdog
 448          */
 449         if (!mrst_identify_cpu())
 450                 return -ENODEV;
 451
 452         /* Check boot parameters to verify that their initial values */
 453         /* are in range. */
 454         /* Check value of timer_set boot parameter */
 455         if ((timer_set < MIN_TIME_CYCLE) ||
 456             (timer_set > MAX_TIME - MIN_TIME_CYCLE)) {
 457                 pr_err("Watchdog timer: value of timer_set %x (hex) "
 458                   "is out of range from %x to %x (hex)\n",
 459                   timer_set, MIN_TIME_CYCLE, MAX_TIME - MIN_TIME_CYCLE);
 460                 return -EINVAL;
 461         }
 462
 463         /* Check value of timer_margin boot parameter */
 464         if (check_timer_margin(timer_margin))
 465                 return -EINVAL;
 466
 467         watchdog_device.timer_tbl_ptr = sfi_get_mtmr(sfi_mtimer_num-1);
 468
 469         if (watchdog_device.timer_tbl_ptr == NULL) {
 470                 pr_debug("Watchdog timer - Intel SCU watchdog: timer is not available\n");
 471                 return -ENODEV;
 472         }
 473         /* make sure the timer exists */
 474         if (watchdog_device.timer_tbl_ptr->phys_addr == 0) {
 475                 pr_debug("Watchdog timer - Intel SCU watchdog - timer %d does not have valid physical memory\n",
 476                                                                 sfi_mtimer_num);
 477                 return -ENODEV;
 478         }
 479
 480         if (watchdog_device.timer_tbl_ptr->irq == 0) {
 481                 pr_debug("Watchdog timer: timer %d invalid irq\n",
 482                                                         sfi_mtimer_num);
 483                 return -ENODEV;
 484         }
 485
 486         tmp_addr = ioremap_nocache(watchdog_device.timer_tbl_ptr->phys_addr,
 487                         20);
 488
 489         if (tmp_addr == NULL) {
 490                 pr_debug("Watchdog timer: timer unable to ioremap\n");
 491                 return -ENOMEM;
 492         }
 493
 494         watchdog_device.timer_load_count_addr = tmp_addr++;
 495         watchdog_device.timer_current_value_addr = tmp_addr++;
 496         watchdog_device.timer_control_addr = tmp_addr++;
 497         watchdog_device.timer_clear_interrupt_addr = tmp_addr++;
 498         watchdog_device.timer_interrupt_status_addr = tmp_addr++;
 499
 500         /* Set the default time values in device structure */
 501
 502         watchdog_device.timer_set = timer_set;
 503         watchdog_device.threshold =
 504                 timer_margin * watchdog_device.timer_tbl_ptr->freq_hz;
 505         watchdog_device.soft_threshold =
 506                 (watchdog_device.timer_set - timer_margin)
 507                 * watchdog_device.timer_tbl_ptr->freq_hz;
 508
 509
 510         watchdog_device.intel_scu_notifier.notifier_call =
 511                 intel_scu_notify_sys;
 512
 513         ret = register_reboot_notifier(&watchdog_device.intel_scu_notifier);
 514         if (ret) {
 515                 pr_err("Watchdog timer: cannot register notifier %d)\n", ret);
 516                 goto register_reboot_error;
 517         }
 518
 519         watchdog_device.miscdev.minor = WATCHDOG_MINOR;
 520         watchdog_device.miscdev.name = "watchdog";
 521         watchdog_device.miscdev.fops = &intel_scu_fops;
 522
 523         ret = misc_register(&watchdog_device.miscdev);
 524         if (ret) {
 525                 pr_err("Watchdog timer: cannot register miscdev %d err =%d\n",
 526                                                         WATCHDOG_MINOR, ret);
 527                 goto misc_register_error;
 528         }
 529
 530         ret = request_irq((unsigned int)watchdog_device.timer_tbl_ptr->irq,
 531                 watchdog_timer_interrupt,
 532                 IRQF_SHARED, "watchdog",
 533                 &watchdog_device.timer_load_count_addr);
 534         if (ret) {
 535                 pr_err("Watchdog timer: error requesting irq %d\n", ret);
 536                 goto request_irq_error;
 537         }
 538         /* Make sure timer is disabled before returning */
 539         intel_scu_stop();
 540         return 0;
 541
 542 /* error cleanup */
 543
 544 request_irq_error:
 545         misc_deregister(&watchdog_device.miscdev);
 546 misc_register_error:
 547         unregister_reboot_notifier(&watchdog_device.intel_scu_notifier);
 548 register_reboot_error:
 549         intel_scu_stop();
 550         iounmap(watchdog_device.timer_load_count_addr);
 551         return ret;
 552 }
 553
 554 static void __exit intel_scu_watchdog_exit(void)
 555 {
 556
 557         misc_deregister(&watchdog_device.miscdev);
 558         unregister_reboot_notifier(&watchdog_device.intel_scu_notifier);
 559         /* disable the timer */
 560         iowrite32(0x00000002, watchdog_device.timer_control_addr);
 561         iounmap(watchdog_device.timer_load_count_addr);
 562 }
 563
 564 late_initcall(intel_scu_watchdog_init);
 565 module_exit(intel_scu_watchdog_exit);
 566
 567 MODULE_AUTHOR("Intel Corporation");
 568 MODULE_DESCRIPTION("Intel SCU Watchdog Device Driver");
 569 MODULE_LICENSE("GPL");
 570 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 571 MODULE_VERSION(WDT_VER);