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