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         pm_runtime_get_sync(wdev->dev);
 130
 131         /* just count up at 32 KHz */
 132         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 133                 cpu_relax();
 134
 135         __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
 136         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 137                 cpu_relax();
 138
 139         pm_runtime_put_sync(wdev->dev);
 140 }
 141
 142 /*
 143  *      Allow only one task to hold it open
 144  */
 145 static int omap_wdt_open(struct inode *inode, struct file *file)
 146 {
 147         struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 148         void __iomem *base = wdev->base;
 149
 150         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 151                 return -EBUSY;
 152
 153         pm_runtime_get_sync(wdev->dev);
 154
 155         /* initialize prescaler */
 156         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 157                 cpu_relax();
 158
 159         __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 160         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 161                 cpu_relax();
 162
 163         file->private_data = (void *) wdev;
 164
 165         omap_wdt_set_timeout(wdev);
 166         omap_wdt_ping(wdev); /* trigger loading of new timeout value */
 167         omap_wdt_enable(wdev);
 168
 169         pm_runtime_put_sync(wdev->dev);
 170
 171         return nonseekable_open(inode, file);
 172 }
 173
 174 static int omap_wdt_release(struct inode *inode, struct file *file)
 175 {
 176         struct omap_wdt_dev *wdev = file->private_data;
 177
 178         /*
 179          *      Shut off the timer unless NOWAYOUT is defined.
 180          */
 181 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 182         pm_runtime_get_sync(wdev->dev);
 183
 184         omap_wdt_disable(wdev);
 185
 186         pm_runtime_put_sync(wdev->dev);
 187 #else
 188         pr_crit("Unexpected close, not stopping!\n");
 189 #endif
 190         wdev->omap_wdt_users = 0;
 191
 192         return 0;
 193 }
 194
 195 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 196                 size_t len, loff_t *ppos)
 197 {
 198         struct omap_wdt_dev *wdev = file->private_data;
 199
 200         /* Refresh LOAD_TIME. */
 201         if (len) {
 202                 pm_runtime_get_sync(wdev->dev);
 203                 spin_lock(&wdt_lock);
 204                 omap_wdt_ping(wdev);
 205                 spin_unlock(&wdt_lock);
 206                 pm_runtime_put_sync(wdev->dev);
 207         }
 208         return len;
 209 }
 210
 211 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 212                                                 unsigned long arg)
 213 {
 214         struct omap_wdt_dev *wdev;
 215         int new_margin;
 216         static const struct watchdog_info ident = {
 217                 .identity = "OMAP Watchdog",
 218                 .options = WDIOF_SETTIMEOUT,
 219                 .firmware_version = 0,
 220         };
 221
 222         wdev = file->private_data;
 223
 224         switch (cmd) {
 225         case WDIOC_GETSUPPORT:
 226                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 227                                 sizeof(ident));
 228         case WDIOC_GETSTATUS:
 229                 return put_user(0, (int __user *)arg);
 230         case WDIOC_GETBOOTSTATUS:
 231                 if (cpu_is_omap16xx())
 232                         return put_user(__raw_readw(ARM_SYSST),
 233                                         (int __user *)arg);
 234                 if (cpu_is_omap24xx())
 235                         return put_user(omap_prcm_get_reset_sources(),
 236                                         (int __user *)arg);
 237                 return put_user(0, (int __user *)arg);
 238         case WDIOC_KEEPALIVE:
 239                 pm_runtime_get_sync(wdev->dev);
 240                 spin_lock(&wdt_lock);
 241                 omap_wdt_ping(wdev);
 242                 spin_unlock(&wdt_lock);
 243                 pm_runtime_put_sync(wdev->dev);
 244                 return 0;
 245         case WDIOC_SETTIMEOUT:
 246                 if (get_user(new_margin, (int __user *)arg))
 247                         return -EFAULT;
 248                 omap_wdt_adjust_timeout(new_margin);
 249
 250                 pm_runtime_get_sync(wdev->dev);
 251                 spin_lock(&wdt_lock);
 252                 omap_wdt_disable(wdev);
 253                 omap_wdt_set_timeout(wdev);
 254                 omap_wdt_enable(wdev);
 255
 256                 omap_wdt_ping(wdev);
 257                 spin_unlock(&wdt_lock);
 258                 pm_runtime_put_sync(wdev->dev);
 259                 /* Fall */
 260         case WDIOC_GETTIMEOUT:
 261                 return put_user(timer_margin, (int __user *)arg);
 262         default:
 263                 return -ENOTTY;
 264         }
 265 }
 266
 267 static const struct file_operations omap_wdt_fops = {
 268         .owner = THIS_MODULE,
 269         .write = omap_wdt_write,
 270         .unlocked_ioctl = omap_wdt_ioctl,
 271         .open = omap_wdt_open,
 272         .release = omap_wdt_release,
 273         .llseek = no_llseek,
 274 };
 275
 276 static int __devinit omap_wdt_probe(struct platform_device *pdev)
 277 {
 278         struct resource *res, *mem;
 279         struct omap_wdt_dev *wdev;
 280         int ret;
 281
 282         /* reserve static register mappings */
 283         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 284         if (!res) {
 285                 ret = -ENOENT;
 286                 goto err_get_resource;
 287         }
 288
 289         if (omap_wdt_dev) {
 290                 ret = -EBUSY;
 291                 goto err_busy;
 292         }
 293
 294         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 295         if (!mem) {
 296                 ret = -EBUSY;
 297                 goto err_busy;
 298         }
 299
 300         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 301         if (!wdev) {
 302                 ret = -ENOMEM;
 303                 goto err_kzalloc;
 304         }
 305
 306         wdev->omap_wdt_users = 0;
 307         wdev->mem = mem;
 308         wdev->dev = &pdev->dev;
 309
 310         wdev->base = ioremap(res->start, resource_size(res));
 311         if (!wdev->base) {
 312                 ret = -ENOMEM;
 313                 goto err_ioremap;
 314         }
 315
 316         platform_set_drvdata(pdev, wdev);
 317
 318         pm_runtime_enable(wdev->dev);
 319         pm_runtime_get_sync(wdev->dev);
 320
 321         omap_wdt_disable(wdev);
 322         omap_wdt_adjust_timeout(timer_margin);
 323
 324         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 325         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 326         wdev->omap_wdt_miscdev.name = "watchdog";
 327         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 328
 329         ret = misc_register(&(wdev->omap_wdt_miscdev));
 330         if (ret)
 331                 goto err_misc;
 332
 333         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 334                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 335                 timer_margin);
 336
 337         pm_runtime_put_sync(wdev->dev);
 338
 339         omap_wdt_dev = pdev;
 340
 341         return 0;
 342
 343 err_misc:
 344         pm_runtime_disable(wdev->dev);
 345         platform_set_drvdata(pdev, NULL);
 346         iounmap(wdev->base);
 347
 348 err_ioremap:
 349         wdev->base = NULL;
 350         kfree(wdev);
 351
 352 err_kzalloc:
 353         release_mem_region(res->start, resource_size(res));
 354
 355 err_busy:
 356 err_get_resource:
 357
 358         return ret;
 359 }
 360
 361 static void omap_wdt_shutdown(struct platform_device *pdev)
 362 {
 363         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 364
 365         if (wdev->omap_wdt_users) {
 366                 pm_runtime_get_sync(wdev->dev);
 367                 omap_wdt_disable(wdev);
 368                 pm_runtime_put_sync(wdev->dev);
 369         }
 370 }
 371
 372 static int __devexit omap_wdt_remove(struct platform_device *pdev)
 373 {
 374         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 375         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 376
 377         pm_runtime_disable(wdev->dev);
 378         if (!res)
 379                 return -ENOENT;
 380
 381         misc_deregister(&(wdev->omap_wdt_miscdev));
 382         release_mem_region(res->start, resource_size(res));
 383         platform_set_drvdata(pdev, NULL);
 384
 385         iounmap(wdev->base);
 386
 387         kfree(wdev);
 388         omap_wdt_dev = NULL;
 389
 390         return 0;
 391 }
 392
 393 #ifdef  CONFIG_PM
 394
 395 /* REVISIT ... not clear this is the best way to handle system suspend; and
 396  * it's very inappropriate for selective device suspend (e.g. suspending this
 397  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 398  * may not play well enough with NOWAYOUT...
 399  */
 400
 401 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 402 {
 403         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 404
 405         if (wdev->omap_wdt_users) {
 406                 pm_runtime_get_sync(wdev->dev);
 407                 omap_wdt_disable(wdev);
 408                 pm_runtime_put_sync(wdev->dev);
 409         }
 410
 411         return 0;
 412 }
 413
 414 static int omap_wdt_resume(struct platform_device *pdev)
 415 {
 416         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 417
 418         if (wdev->omap_wdt_users) {
 419                 pm_runtime_get_sync(wdev->dev);
 420                 omap_wdt_enable(wdev);
 421                 omap_wdt_ping(wdev);
 422                 pm_runtime_put_sync(wdev->dev);
 423         }
 424
 425         return 0;
 426 }
 427
 428 #else
 429 #define omap_wdt_suspend        NULL
 430 #define omap_wdt_resume         NULL
 431 #endif
 432
 433 static const struct of_device_id omap_wdt_of_match[] = {
 434         { .compatible = "ti,omap3-wdt", },
 435         {},
 436 };
 437 MODULE_DEVICE_TABLE(of, omap_wdt_of_match);
 438
 439 static struct platform_driver omap_wdt_driver = {
 440         .probe          = omap_wdt_probe,
 441         .remove         = __devexit_p(omap_wdt_remove),
 442         .shutdown       = omap_wdt_shutdown,
 443         .suspend        = omap_wdt_suspend,
 444         .resume         = omap_wdt_resume,
 445         .driver         = {
 446                 .owner  = THIS_MODULE,
 447                 .name   = "omap_wdt",
 448                 .of_match_table = omap_wdt_of_match,
 449         },
 450 };
 451
 452 module_platform_driver(omap_wdt_driver);
 453
 454 MODULE_AUTHOR("George G. Davis");
 455 MODULE_LICENSE("GPL");
 456 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 457 MODULE_ALIAS("platform:omap_wdt");