drivers/watchdog/omap_wdt.c

   1 /*
   2  * omap_wdt.c
   3  *
   4  * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
   5  *
   6  * Author: MontaVista Software, Inc.
   7  *       <gdavis@mvista.com> or <source@mvista.com>
   8  *
   9  * 2003 (c) MontaVista Software, Inc. This file is licensed under the
  10  * terms of the GNU General Public License version 2. This program is
  11  * licensed "as is" without any warranty of any kind, whether express
  12  * or implied.
  13  *
  14  * History:
  15  *
  16  * 20030527: George G. Davis <gdavis@mvista.com>
  17  *      Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
  18  *      (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
  19  *      Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
  20  *
  21  * Copyright (c) 2004 Texas Instruments.
  22  *      1. Modified to support OMAP1610 32-KHz watchdog timer
  23  *      2. Ported to 2.6 kernel
  24  *
  25  * Copyright (c) 2005 David Brownell
  26  *      Use the driver model and standard identifiers; handle bigger timeouts.
  27  */
  28
  29 #include <linux/module.h>
  30 #include <linux/types.h>
  31 #include <linux/kernel.h>
  32 #include <linux/fs.h>
  33 #include <linux/mm.h>
  34 #include <linux/miscdevice.h>
  35 #include <linux/watchdog.h>
  36 #include <linux/reboot.h>
  37 #include <linux/init.h>
  38 #include <linux/err.h>
  39 #include <linux/platform_device.h>
  40 #include <linux/moduleparam.h>
  41 #include <linux/bitops.h>
  42 #include <linux/io.h>
  43 #include <linux/uaccess.h>
  44 #include <linux/slab.h>
  45 #include <linux/pm_runtime.h>
  46 #include <mach/hardware.h>
  47 #include <plat/prcm.h>
  48
  49 #include "omap_wdt.h"
  50
  51 static struct platform_device *omap_wdt_dev;
  52
  53 static unsigned timer_margin;
  54 module_param(timer_margin, uint, 0);
  55 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  56
  57 static unsigned int wdt_trgr_pattern = 0x1234;
  58 static spinlock_t wdt_lock;
  59
  60 struct omap_wdt_dev {
  61         void __iomem    *base;          /* physical */
  62         struct device   *dev;
  63         int             omap_wdt_users;
  64         struct resource *mem;
  65         struct miscdevice omap_wdt_miscdev;
  66 };
  67
  68 static void omap_wdt_ping(struct omap_wdt_dev *wdev)
  69 {
  70         void __iomem    *base = wdev->base;
  71
  72         /* wait for posted write to complete */
  73         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  74                 cpu_relax();
  75
  76         wdt_trgr_pattern = ~wdt_trgr_pattern;
  77         __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  78
  79         /* wait for posted write to complete */
  80         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  81                 cpu_relax();
  82         /* reloaded WCRR from WLDR */
  83 }
  84
  85 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  86 {
  87         void __iomem *base = wdev->base;
  88
  89         /* Sequence to enable the watchdog */
  90         __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
  91         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  92                 cpu_relax();
  93
  94         __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
  95         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  96                 cpu_relax();
  97 }
  98
  99 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 100 {
 101         void __iomem *base = wdev->base;
 102
 103         /* sequence required to disable watchdog */
 104         __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 105         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 106                 cpu_relax();
 107
 108         __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 109         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 110                 cpu_relax();
 111 }
 112
 113 static void omap_wdt_adjust_timeout(unsigned new_timeout)
 114 {
 115         if (new_timeout < TIMER_MARGIN_MIN)
 116                 new_timeout = TIMER_MARGIN_DEFAULT;
 117         if (new_timeout > TIMER_MARGIN_MAX)
 118                 new_timeout = TIMER_MARGIN_MAX;
 119         timer_margin = new_timeout;
 120 }
 121
 122 static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
 123 {
 124         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 125         void __iomem *base = wdev->base;
 126
 127         pm_runtime_get_sync(wdev->dev);
 128
 129         /* just count up at 32 KHz */
 130         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 131                 cpu_relax();
 132
 133         __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
 134         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 135                 cpu_relax();
 136
 137         pm_runtime_put_sync(wdev->dev);
 138 }
 139
 140 /*
 141  *      Allow only one task to hold it open
 142  */
 143 static int omap_wdt_open(struct inode *inode, struct file *file)
 144 {
 145         struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 146         void __iomem *base = wdev->base;
 147
 148         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 149                 return -EBUSY;
 150
 151         pm_runtime_get_sync(wdev->dev);
 152
 153         /*
 154          * Make sure the watchdog is disabled. This is unfortunately required
 155          * because writing to various registers with the watchdog running has no
 156          * effect.
 157          */
 158         omap_wdt_disable(wdev);
 159
 160         /* initialize prescaler */
 161         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 162                 cpu_relax();
 163
 164         __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 165         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 166                 cpu_relax();
 167
 168         file->private_data = (void *) wdev;
 169
 170         omap_wdt_set_timeout(wdev);
 171         omap_wdt_ping(wdev); /* trigger loading of new timeout value */
 172         omap_wdt_enable(wdev);
 173
 174         pm_runtime_put_sync(wdev->dev);
 175
 176         return nonseekable_open(inode, file);
 177 }
 178
 179 static int omap_wdt_release(struct inode *inode, struct file *file)
 180 {
 181         struct omap_wdt_dev *wdev = file->private_data;
 182
 183         /*
 184          *      Shut off the timer unless NOWAYOUT is defined.
 185          */
 186 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 187         pm_runtime_get_sync(wdev->dev);
 188
 189         omap_wdt_disable(wdev);
 190
 191         pm_runtime_put_sync(wdev->dev);
 192 #else
 193         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 194 #endif
 195         wdev->omap_wdt_users = 0;
 196
 197         return 0;
 198 }
 199
 200 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 201                 size_t len, loff_t *ppos)
 202 {
 203         struct omap_wdt_dev *wdev = file->private_data;
 204
 205         /* Refresh LOAD_TIME. */
 206         if (len) {
 207                 pm_runtime_get_sync(wdev->dev);
 208                 spin_lock(&wdt_lock);
 209                 omap_wdt_ping(wdev);
 210                 spin_unlock(&wdt_lock);
 211                 pm_runtime_put_sync(wdev->dev);
 212         }
 213         return len;
 214 }
 215
 216 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 217                                                 unsigned long arg)
 218 {
 219         struct omap_wdt_dev *wdev;
 220         int new_margin;
 221         static const struct watchdog_info ident = {
 222                 .identity = "OMAP Watchdog",
 223                 .options = WDIOF_SETTIMEOUT,
 224                 .firmware_version = 0,
 225         };
 226
 227         wdev = file->private_data;
 228
 229         switch (cmd) {
 230         case WDIOC_GETSUPPORT:
 231                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 232                                 sizeof(ident));
 233         case WDIOC_GETSTATUS:
 234                 return put_user(0, (int __user *)arg);
 235         case WDIOC_GETBOOTSTATUS:
 236                 if (cpu_is_omap16xx())
 237                         return put_user(__raw_readw(ARM_SYSST),
 238                                         (int __user *)arg);
 239                 if (cpu_is_omap24xx())
 240                         return put_user(omap_prcm_get_reset_sources(),
 241                                         (int __user *)arg);
 242         case WDIOC_KEEPALIVE:
 243                 pm_runtime_get_sync(wdev->dev);
 244                 spin_lock(&wdt_lock);
 245                 omap_wdt_ping(wdev);
 246                 spin_unlock(&wdt_lock);
 247                 pm_runtime_put_sync(wdev->dev);
 248                 return 0;
 249         case WDIOC_SETTIMEOUT:
 250                 if (get_user(new_margin, (int __user *)arg))
 251                         return -EFAULT;
 252                 omap_wdt_adjust_timeout(new_margin);
 253
 254                 pm_runtime_get_sync(wdev->dev);
 255                 spin_lock(&wdt_lock);
 256                 omap_wdt_disable(wdev);
 257                 omap_wdt_set_timeout(wdev);
 258                 omap_wdt_enable(wdev);
 259
 260                 omap_wdt_ping(wdev);
 261                 spin_unlock(&wdt_lock);
 262                 pm_runtime_put_sync(wdev->dev);
 263                 /* Fall */
 264         case WDIOC_GETTIMEOUT:
 265                 return put_user(timer_margin, (int __user *)arg);
 266         default:
 267                 return -ENOTTY;
 268         }
 269 }
 270
 271 static const struct file_operations omap_wdt_fops = {
 272         .owner = THIS_MODULE,
 273         .write = omap_wdt_write,
 274         .unlocked_ioctl = omap_wdt_ioctl,
 275         .open = omap_wdt_open,
 276         .release = omap_wdt_release,
 277         .llseek = no_llseek,
 278 };
 279
 280 static int __devinit omap_wdt_probe(struct platform_device *pdev)
 281 {
 282         struct resource *res, *mem;
 283         struct omap_wdt_dev *wdev;
 284         int ret;
 285
 286         /* reserve static register mappings */
 287         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 288         if (!res) {
 289                 ret = -ENOENT;
 290                 goto err_get_resource;
 291         }
 292
 293         if (omap_wdt_dev) {
 294                 ret = -EBUSY;
 295                 goto err_busy;
 296         }
 297
 298         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 299         if (!mem) {
 300                 ret = -EBUSY;
 301                 goto err_busy;
 302         }
 303
 304         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 305         if (!wdev) {
 306                 ret = -ENOMEM;
 307                 goto err_kzalloc;
 308         }
 309
 310         wdev->omap_wdt_users = 0;
 311         wdev->mem = mem;
 312         wdev->dev = &pdev->dev;
 313
 314         wdev->base = ioremap(res->start, resource_size(res));
 315         if (!wdev->base) {
 316                 ret = -ENOMEM;
 317                 goto err_ioremap;
 318         }
 319
 320         platform_set_drvdata(pdev, wdev);
 321
 322         pm_runtime_enable(wdev->dev);
 323         pm_runtime_get_sync(wdev->dev);
 324
 325         omap_wdt_disable(wdev);
 326         omap_wdt_adjust_timeout(timer_margin);
 327
 328         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 329         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 330         wdev->omap_wdt_miscdev.name = "watchdog";
 331         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 332
 333         ret = misc_register(&(wdev->omap_wdt_miscdev));
 334         if (ret)
 335                 goto err_misc;
 336
 337         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 338                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 339                 timer_margin);
 340
 341         pm_runtime_put_sync(wdev->dev);
 342
 343         omap_wdt_dev = pdev;
 344
 345         return 0;
 346
 347 err_misc:
 348         platform_set_drvdata(pdev, NULL);
 349         iounmap(wdev->base);
 350
 351 err_ioremap:
 352         wdev->base = NULL;
 353         kfree(wdev);
 354
 355 err_kzalloc:
 356         release_mem_region(res->start, resource_size(res));
 357
 358 err_busy:
 359 err_get_resource:
 360
 361         return ret;
 362 }
 363
 364 static void omap_wdt_shutdown(struct platform_device *pdev)
 365 {
 366         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 367
 368         if (wdev->omap_wdt_users) {
 369                 pm_runtime_get_sync(wdev->dev);
 370                 omap_wdt_disable(wdev);
 371                 pm_runtime_put_sync(wdev->dev);
 372         }
 373 }
 374
 375 static int __devexit omap_wdt_remove(struct platform_device *pdev)
 376 {
 377         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 378         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 379
 380         if (!res)
 381                 return -ENOENT;
 382
 383         misc_deregister(&(wdev->omap_wdt_miscdev));
 384         release_mem_region(res->start, resource_size(res));
 385         platform_set_drvdata(pdev, NULL);
 386
 387         iounmap(wdev->base);
 388
 389         kfree(wdev);
 390         omap_wdt_dev = NULL;
 391
 392         return 0;
 393 }
 394
 395 #ifdef  CONFIG_PM
 396
 397 /* REVISIT ... not clear this is the best way to handle system suspend; and
 398  * it's very inappropriate for selective device suspend (e.g. suspending this
 399  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 400  * may not play well enough with NOWAYOUT...
 401  */
 402
 403 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 404 {
 405         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 406
 407         if (wdev->omap_wdt_users) {
 408                 pm_runtime_get_sync(wdev->dev);
 409                 omap_wdt_disable(wdev);
 410                 pm_runtime_put_sync(wdev->dev);
 411         }
 412
 413         return 0;
 414 }
 415
 416 static int omap_wdt_resume(struct platform_device *pdev)
 417 {
 418         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 419
 420         if (wdev->omap_wdt_users) {
 421                 pm_runtime_get_sync(wdev->dev);
 422                 omap_wdt_enable(wdev);
 423                 omap_wdt_ping(wdev);
 424                 pm_runtime_put_sync(wdev->dev);
 425         }
 426
 427         return 0;
 428 }
 429
 430 #else
 431 #define omap_wdt_suspend        NULL
 432 #define omap_wdt_resume         NULL
 433 #endif
 434
 435 static struct platform_driver omap_wdt_driver = {
 436         .probe          = omap_wdt_probe,
 437         .remove         = __devexit_p(omap_wdt_remove),
 438         .shutdown       = omap_wdt_shutdown,
 439         .suspend        = omap_wdt_suspend,
 440         .resume         = omap_wdt_resume,
 441         .driver         = {
 442                 .owner  = THIS_MODULE,
 443                 .name   = "omap_wdt",
 444         },
 445 };
 446
 447 static int __init omap_wdt_init(void)
 448 {
 449         spin_lock_init(&wdt_lock);
 450         return platform_driver_register(&omap_wdt_driver);
 451 }
 452
 453 static void __exit omap_wdt_exit(void)
 454 {
 455         platform_driver_unregister(&omap_wdt_driver);
 456 }
 457
 458 module_init(omap_wdt_init);
 459 module_exit(omap_wdt_exit);
 460
 461 MODULE_AUTHOR("George G. Davis");
 462 MODULE_LICENSE("GPL");
 463 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 464 MODULE_ALIAS("platform:omap_wdt");