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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  30
  31 #include <linux/module.h>
  32 #include <linux/types.h>
  33 #include <linux/kernel.h>
  34 #include <linux/fs.h>
  35 #include <linux/mm.h>
  36 #include <linux/miscdevice.h>
  37 #include <linux/watchdog.h>
  38 #include <linux/reboot.h>
  39 #include <linux/init.h>
  40 #include <linux/err.h>
  41 #include <linux/platform_device.h>
  42 #include <linux/moduleparam.h>
  43 #include <linux/bitops.h>
  44 #include <linux/io.h>
  45 #include <linux/uaccess.h>
  46 #include <linux/slab.h>
  47 #include <linux/pm_runtime.h>
  48 #include <mach/hardware.h>
  49 #include <plat/prcm.h>
  50
  51 #include "omap_wdt.h"
  52
  53 static struct platform_device *omap_wdt_dev;
  54
  55 static unsigned timer_margin;
  56 module_param(timer_margin, uint, 0);
  57 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  58
  59 static unsigned int wdt_trgr_pattern = 0x1234;
  60 static DEFINE_SPINLOCK(wdt_lock);
  61
  62 struct omap_wdt_dev {
  63         void __iomem    *base;          /* physical */
  64         struct device   *dev;
  65         int             omap_wdt_users;
  66         struct resource *mem;
  67         struct miscdevice omap_wdt_miscdev;
  68 };
  69
  70 static void omap_wdt_ping(struct omap_wdt_dev *wdev)
  71 {
  72         void __iomem    *base = wdev->base;
  73
  74         /* wait for posted write to complete */
  75         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  76                 cpu_relax();
  77
  78         wdt_trgr_pattern = ~wdt_trgr_pattern;
  79         __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  80
  81         /* wait for posted write to complete */
  82         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  83                 cpu_relax();
  84         /* reloaded WCRR from WLDR */
  85 }
  86
  87 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  88 {
  89         void __iomem *base = wdev->base;
  90
  91         /* Sequence to enable the watchdog */
  92         __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
  93         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  94                 cpu_relax();
  95
  96         __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
  97         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  98                 cpu_relax();
  99 }
 100
 101 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 102 {
 103         void __iomem *base = wdev->base;
 104
 105         /* sequence required to disable watchdog */
 106         __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 107         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 108                 cpu_relax();
 109
 110         __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 111         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 112                 cpu_relax();
 113 }
 114
 115 static void omap_wdt_adjust_timeout(unsigned new_timeout)
 116 {
 117         if (new_timeout < TIMER_MARGIN_MIN)
 118                 new_timeout = TIMER_MARGIN_DEFAULT;
 119         if (new_timeout > TIMER_MARGIN_MAX)
 120                 new_timeout = TIMER_MARGIN_MAX;
 121         timer_margin = new_timeout;
 122 }
 123
 124 static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
 125 {
 126         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 127         void __iomem *base = wdev->base;
 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
 138 /*
 139  *      Allow only one task to hold it open
 140  */
 141 static int omap_wdt_open(struct inode *inode, struct file *file)
 142 {
 143         struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 144         void __iomem *base = wdev->base;
 145
 146         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 147                 return -EBUSY;
 148
 149         pm_runtime_get_sync(wdev->dev);
 150
 151         /* initialize prescaler */
 152         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 153                 cpu_relax();
 154
 155         __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 156         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 157                 cpu_relax();
 158
 159         file->private_data = (void *) wdev;
 160
 161         omap_wdt_set_timeout(wdev);
 162         omap_wdt_ping(wdev); /* trigger loading of new timeout value */
 163         omap_wdt_enable(wdev);
 164
 165         return nonseekable_open(inode, file);
 166 }
 167
 168 static int omap_wdt_release(struct inode *inode, struct file *file)
 169 {
 170         struct omap_wdt_dev *wdev = file->private_data;
 171
 172         /*
 173          *      Shut off the timer unless NOWAYOUT is defined.
 174          */
 175 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 176         omap_wdt_disable(wdev);
 177
 178         pm_runtime_put_sync(wdev->dev);
 179 #else
 180         pr_crit("Unexpected close, not stopping!\n");
 181 #endif
 182         wdev->omap_wdt_users = 0;
 183
 184         return 0;
 185 }
 186
 187 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 188                 size_t len, loff_t *ppos)
 189 {
 190         struct omap_wdt_dev *wdev = file->private_data;
 191
 192         /* Refresh LOAD_TIME. */
 193         if (len) {
 194                 spin_lock(&wdt_lock);
 195                 omap_wdt_ping(wdev);
 196                 spin_unlock(&wdt_lock);
 197         }
 198         return len;
 199 }
 200
 201 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 202                                                 unsigned long arg)
 203 {
 204         struct omap_wdt_dev *wdev;
 205         int new_margin;
 206         static const struct watchdog_info ident = {
 207                 .identity = "OMAP Watchdog",
 208                 .options = WDIOF_SETTIMEOUT,
 209                 .firmware_version = 0,
 210         };
 211
 212         wdev = file->private_data;
 213
 214         switch (cmd) {
 215         case WDIOC_GETSUPPORT:
 216                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 217                                 sizeof(ident));
 218         case WDIOC_GETSTATUS:
 219                 return put_user(0, (int __user *)arg);
 220         case WDIOC_GETBOOTSTATUS:
 221                 if (cpu_is_omap16xx())
 222                         return put_user(__raw_readw(ARM_SYSST),
 223                                         (int __user *)arg);
 224                 if (cpu_is_omap24xx())
 225                         return put_user(omap_prcm_get_reset_sources(),
 226                                         (int __user *)arg);
 227                 return put_user(0, (int __user *)arg);
 228         case WDIOC_KEEPALIVE:
 229                 spin_lock(&wdt_lock);
 230                 omap_wdt_ping(wdev);
 231                 spin_unlock(&wdt_lock);
 232                 return 0;
 233         case WDIOC_SETTIMEOUT:
 234                 if (get_user(new_margin, (int __user *)arg))
 235                         return -EFAULT;
 236                 omap_wdt_adjust_timeout(new_margin);
 237
 238                 spin_lock(&wdt_lock);
 239                 omap_wdt_disable(wdev);
 240                 omap_wdt_set_timeout(wdev);
 241                 omap_wdt_enable(wdev);
 242
 243                 omap_wdt_ping(wdev);
 244                 spin_unlock(&wdt_lock);
 245                 /* Fall */
 246         case WDIOC_GETTIMEOUT:
 247                 return put_user(timer_margin, (int __user *)arg);
 248         default:
 249                 return -ENOTTY;
 250         }
 251 }
 252
 253 static const struct file_operations omap_wdt_fops = {
 254         .owner = THIS_MODULE,
 255         .write = omap_wdt_write,
 256         .unlocked_ioctl = omap_wdt_ioctl,
 257         .open = omap_wdt_open,
 258         .release = omap_wdt_release,
 259         .llseek = no_llseek,
 260 };
 261
 262 static int __devinit omap_wdt_probe(struct platform_device *pdev)
 263 {
 264         struct resource *res, *mem;
 265         struct omap_wdt_dev *wdev;
 266         int ret;
 267
 268         /* reserve static register mappings */
 269         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 270         if (!res) {
 271                 ret = -ENOENT;
 272                 goto err_get_resource;
 273         }
 274
 275         if (omap_wdt_dev) {
 276                 ret = -EBUSY;
 277                 goto err_busy;
 278         }
 279
 280         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 281         if (!mem) {
 282                 ret = -EBUSY;
 283                 goto err_busy;
 284         }
 285
 286         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 287         if (!wdev) {
 288                 ret = -ENOMEM;
 289                 goto err_kzalloc;
 290         }
 291
 292         wdev->omap_wdt_users = 0;
 293         wdev->mem = mem;
 294         wdev->dev = &pdev->dev;
 295
 296         wdev->base = ioremap(res->start, resource_size(res));
 297         if (!wdev->base) {
 298                 ret = -ENOMEM;
 299                 goto err_ioremap;
 300         }
 301
 302         platform_set_drvdata(pdev, wdev);
 303
 304         pm_runtime_enable(wdev->dev);
 305         pm_runtime_get_sync(wdev->dev);
 306
 307         omap_wdt_disable(wdev);
 308         omap_wdt_adjust_timeout(timer_margin);
 309
 310         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 311         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 312         wdev->omap_wdt_miscdev.name = "watchdog";
 313         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 314
 315         ret = misc_register(&(wdev->omap_wdt_miscdev));
 316         if (ret)
 317                 goto err_misc;
 318
 319         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 320                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 321                 timer_margin);
 322
 323         pm_runtime_put_sync(wdev->dev);
 324
 325         omap_wdt_dev = pdev;
 326
 327         return 0;
 328
 329 err_misc:
 330         pm_runtime_disable(wdev->dev);
 331         platform_set_drvdata(pdev, NULL);
 332         iounmap(wdev->base);
 333
 334 err_ioremap:
 335         wdev->base = NULL;
 336         kfree(wdev);
 337
 338 err_kzalloc:
 339         release_mem_region(res->start, resource_size(res));
 340
 341 err_busy:
 342 err_get_resource:
 343
 344         return ret;
 345 }
 346
 347 static void omap_wdt_shutdown(struct platform_device *pdev)
 348 {
 349         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 350
 351         if (wdev->omap_wdt_users) {
 352                 omap_wdt_disable(wdev);
 353                 pm_runtime_put_sync(wdev->dev);
 354         }
 355 }
 356
 357 static int __devexit omap_wdt_remove(struct platform_device *pdev)
 358 {
 359         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 360         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 361
 362         pm_runtime_disable(wdev->dev);
 363         if (!res)
 364                 return -ENOENT;
 365
 366         misc_deregister(&(wdev->omap_wdt_miscdev));
 367         release_mem_region(res->start, resource_size(res));
 368         platform_set_drvdata(pdev, NULL);
 369
 370         iounmap(wdev->base);
 371
 372         kfree(wdev);
 373         omap_wdt_dev = NULL;
 374
 375         return 0;
 376 }
 377
 378 #ifdef  CONFIG_PM
 379
 380 /* REVISIT ... not clear this is the best way to handle system suspend; and
 381  * it's very inappropriate for selective device suspend (e.g. suspending this
 382  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 383  * may not play well enough with NOWAYOUT...
 384  */
 385
 386 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 387 {
 388         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 389
 390         if (wdev->omap_wdt_users) {
 391                 omap_wdt_disable(wdev);
 392                 pm_runtime_put_sync(wdev->dev);
 393         }
 394
 395         return 0;
 396 }
 397
 398 static int omap_wdt_resume(struct platform_device *pdev)
 399 {
 400         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 401
 402         if (wdev->omap_wdt_users) {
 403                 pm_runtime_get_sync(wdev->dev);
 404                 omap_wdt_enable(wdev);
 405                 omap_wdt_ping(wdev);
 406         }
 407
 408         return 0;
 409 }
 410
 411 #else
 412 #define omap_wdt_suspend        NULL
 413 #define omap_wdt_resume         NULL
 414 #endif
 415
 416 static const struct of_device_id omap_wdt_of_match[] = {
 417         { .compatible = "ti,omap3-wdt", },
 418         {},
 419 };
 420 MODULE_DEVICE_TABLE(of, omap_wdt_of_match);
 421
 422 static struct platform_driver omap_wdt_driver = {
 423         .probe          = omap_wdt_probe,
 424         .remove         = __devexit_p(omap_wdt_remove),
 425         .shutdown       = omap_wdt_shutdown,
 426         .suspend        = omap_wdt_suspend,
 427         .resume         = omap_wdt_resume,
 428         .driver         = {
 429                 .owner  = THIS_MODULE,
 430                 .name   = "omap_wdt",
 431                 .of_match_table = omap_wdt_of_match,
 432         },
 433 };
 434
 435 module_platform_driver(omap_wdt_driver);
 436
 437 MODULE_AUTHOR("George G. Davis");
 438 MODULE_LICENSE("GPL");
 439 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 440 MODULE_ALIAS("platform:omap_wdt");