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         /* just count up at 32 KHz */
 128         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 129                 cpu_relax();
 130
 131         __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
 132         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 133                 cpu_relax();
 134 }
 135
 136 /*
 137  *      Allow only one task to hold it open
 138  */
 139 static int omap_wdt_open(struct inode *inode, struct file *file)
 140 {
 141         struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 142         void __iomem *base = wdev->base;
 143
 144         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 145                 return -EBUSY;
 146
 147         pm_runtime_get_sync(wdev->dev);
 148
 149         /* initialize prescaler */
 150         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 151                 cpu_relax();
 152
 153         __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 154         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 155                 cpu_relax();
 156
 157         file->private_data = (void *) wdev;
 158
 159         omap_wdt_set_timeout(wdev);
 160         omap_wdt_ping(wdev); /* trigger loading of new timeout value */
 161         omap_wdt_enable(wdev);
 162
 163         return nonseekable_open(inode, file);
 164 }
 165
 166 static int omap_wdt_release(struct inode *inode, struct file *file)
 167 {
 168         struct omap_wdt_dev *wdev = file->private_data;
 169
 170         /*
 171          *      Shut off the timer unless NOWAYOUT is defined.
 172          */
 173 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 174
 175         omap_wdt_disable(wdev);
 176
 177         pm_runtime_put_sync(wdev->dev);
 178 #else
 179         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 180 #endif
 181         wdev->omap_wdt_users = 0;
 182
 183         return 0;
 184 }
 185
 186 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 187                 size_t len, loff_t *ppos)
 188 {
 189         struct omap_wdt_dev *wdev = file->private_data;
 190
 191         /* Refresh LOAD_TIME. */
 192         if (len) {
 193                 spin_lock(&wdt_lock);
 194                 omap_wdt_ping(wdev);
 195                 spin_unlock(&wdt_lock);
 196         }
 197         return len;
 198 }
 199
 200 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 201                                                 unsigned long arg)
 202 {
 203         struct omap_wdt_dev *wdev;
 204         int new_margin;
 205         static const struct watchdog_info ident = {
 206                 .identity = "OMAP Watchdog",
 207                 .options = WDIOF_SETTIMEOUT,
 208                 .firmware_version = 0,
 209         };
 210
 211         wdev = file->private_data;
 212
 213         switch (cmd) {
 214         case WDIOC_GETSUPPORT:
 215                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 216                                 sizeof(ident));
 217         case WDIOC_GETSTATUS:
 218                 return put_user(0, (int __user *)arg);
 219         case WDIOC_GETBOOTSTATUS:
 220                 if (cpu_is_omap16xx())
 221                         return put_user(__raw_readw(ARM_SYSST),
 222                                         (int __user *)arg);
 223                 if (cpu_is_omap24xx())
 224                         return put_user(omap_prcm_get_reset_sources(),
 225                                         (int __user *)arg);
 226         case WDIOC_KEEPALIVE:
 227                 spin_lock(&wdt_lock);
 228                 omap_wdt_ping(wdev);
 229                 spin_unlock(&wdt_lock);
 230                 return 0;
 231         case WDIOC_SETTIMEOUT:
 232                 if (get_user(new_margin, (int __user *)arg))
 233                         return -EFAULT;
 234                 omap_wdt_adjust_timeout(new_margin);
 235
 236                 spin_lock(&wdt_lock);
 237                 omap_wdt_disable(wdev);
 238                 omap_wdt_set_timeout(wdev);
 239                 omap_wdt_enable(wdev);
 240
 241                 omap_wdt_ping(wdev);
 242                 spin_unlock(&wdt_lock);
 243                 /* Fall */
 244         case WDIOC_GETTIMEOUT:
 245                 return put_user(timer_margin, (int __user *)arg);
 246         default:
 247                 return -ENOTTY;
 248         }
 249 }
 250
 251 static const struct file_operations omap_wdt_fops = {
 252         .owner = THIS_MODULE,
 253         .write = omap_wdt_write,
 254         .unlocked_ioctl = omap_wdt_ioctl,
 255         .open = omap_wdt_open,
 256         .release = omap_wdt_release,
 257         .llseek = no_llseek,
 258 };
 259
 260 static int __devinit omap_wdt_probe(struct platform_device *pdev)
 261 {
 262         struct resource *res, *mem;
 263         struct omap_wdt_dev *wdev;
 264         int ret;
 265
 266         /* reserve static register mappings */
 267         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 268         if (!res) {
 269                 ret = -ENOENT;
 270                 goto err_get_resource;
 271         }
 272
 273         if (omap_wdt_dev) {
 274                 ret = -EBUSY;
 275                 goto err_busy;
 276         }
 277
 278         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 279         if (!mem) {
 280                 ret = -EBUSY;
 281                 goto err_busy;
 282         }
 283
 284         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 285         if (!wdev) {
 286                 ret = -ENOMEM;
 287                 goto err_kzalloc;
 288         }
 289
 290         wdev->omap_wdt_users = 0;
 291         wdev->mem = mem;
 292         wdev->dev = &pdev->dev;
 293
 294         wdev->base = ioremap(res->start, resource_size(res));
 295         if (!wdev->base) {
 296                 ret = -ENOMEM;
 297                 goto err_ioremap;
 298         }
 299
 300         platform_set_drvdata(pdev, wdev);
 301
 302         pm_runtime_enable(wdev->dev);
 303         pm_runtime_get_sync(wdev->dev);
 304
 305         omap_wdt_disable(wdev);
 306         omap_wdt_adjust_timeout(timer_margin);
 307
 308         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 309         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 310         wdev->omap_wdt_miscdev.name = "watchdog";
 311         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 312
 313         ret = misc_register(&(wdev->omap_wdt_miscdev));
 314         if (ret)
 315                 goto err_misc;
 316
 317         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 318                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 319                 timer_margin);
 320
 321         pm_runtime_put_sync(wdev->dev);
 322
 323         omap_wdt_dev = pdev;
 324
 325         return 0;
 326
 327 err_misc:
 328         platform_set_drvdata(pdev, NULL);
 329         iounmap(wdev->base);
 330
 331 err_ioremap:
 332         wdev->base = NULL;
 333         kfree(wdev);
 334
 335 err_kzalloc:
 336         release_mem_region(res->start, resource_size(res));
 337
 338 err_busy:
 339 err_get_resource:
 340
 341         return ret;
 342 }
 343
 344 static void omap_wdt_shutdown(struct platform_device *pdev)
 345 {
 346         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 347
 348         if (wdev->omap_wdt_users)
 349                 omap_wdt_disable(wdev);
 350 }
 351
 352 static int __devexit omap_wdt_remove(struct platform_device *pdev)
 353 {
 354         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 355         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 356
 357         if (!res)
 358                 return -ENOENT;
 359
 360         misc_deregister(&(wdev->omap_wdt_miscdev));
 361         release_mem_region(res->start, resource_size(res));
 362         platform_set_drvdata(pdev, NULL);
 363
 364         iounmap(wdev->base);
 365
 366         kfree(wdev);
 367         omap_wdt_dev = NULL;
 368
 369         return 0;
 370 }
 371
 372 #ifdef  CONFIG_PM
 373
 374 /* REVISIT ... not clear this is the best way to handle system suspend; and
 375  * it's very inappropriate for selective device suspend (e.g. suspending this
 376  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 377  * may not play well enough with NOWAYOUT...
 378  */
 379
 380 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 381 {
 382         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 383
 384         if (wdev->omap_wdt_users)
 385                 omap_wdt_disable(wdev);
 386
 387         return 0;
 388 }
 389
 390 static int omap_wdt_resume(struct platform_device *pdev)
 391 {
 392         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 393
 394         if (wdev->omap_wdt_users) {
 395                 omap_wdt_enable(wdev);
 396                 omap_wdt_ping(wdev);
 397         }
 398
 399         return 0;
 400 }
 401
 402 #else
 403 #define omap_wdt_suspend        NULL
 404 #define omap_wdt_resume         NULL
 405 #endif
 406
 407 static struct platform_driver omap_wdt_driver = {
 408         .probe          = omap_wdt_probe,
 409         .remove         = __devexit_p(omap_wdt_remove),
 410         .shutdown       = omap_wdt_shutdown,
 411         .suspend        = omap_wdt_suspend,
 412         .resume         = omap_wdt_resume,
 413         .driver         = {
 414                 .owner  = THIS_MODULE,
 415                 .name   = "omap_wdt",
 416         },
 417 };
 418
 419 static int __init omap_wdt_init(void)
 420 {
 421         spin_lock_init(&wdt_lock);
 422         return platform_driver_register(&omap_wdt_driver);
 423 }
 424
 425 static void __exit omap_wdt_exit(void)
 426 {
 427         platform_driver_unregister(&omap_wdt_driver);
 428 }
 429
 430 module_init(omap_wdt_init);
 431 module_exit(omap_wdt_exit);
 432
 433 MODULE_AUTHOR("George G. Davis");
 434 MODULE_LICENSE("GPL");
 435 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 436 MODULE_ALIAS("platform:omap_wdt");