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/cpu.h>
  50 #include <plat/prcm.h>
  51
  52 #include "omap_wdt.h"
  53
  54 static struct platform_device *omap_wdt_dev;
  55
  56 static unsigned timer_margin;
  57 module_param(timer_margin, uint, 0);
  58 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  59
  60 static unsigned int wdt_trgr_pattern = 0x1234;
  61 static DEFINE_SPINLOCK(wdt_lock);
  62
  63 struct omap_wdt_dev {
  64         void __iomem    *base;          /* physical */
  65         struct device   *dev;
  66         int             omap_wdt_users;
  67         struct resource *mem;
  68         struct miscdevice omap_wdt_miscdev;
  69 };
  70
  71 static void omap_wdt_ping(struct omap_wdt_dev *wdev)
  72 {
  73         void __iomem    *base = wdev->base;
  74
  75         /* wait for posted write to complete */
  76         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  77                 cpu_relax();
  78
  79         wdt_trgr_pattern = ~wdt_trgr_pattern;
  80         __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  81
  82         /* wait for posted write to complete */
  83         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  84                 cpu_relax();
  85         /* reloaded WCRR from WLDR */
  86 }
  87
  88 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  89 {
  90         void __iomem *base = wdev->base;
  91
  92         /* Sequence to enable the watchdog */
  93         __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
  94         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  95                 cpu_relax();
  96
  97         __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
  98         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  99                 cpu_relax();
 100 }
 101
 102 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 103 {
 104         void __iomem *base = wdev->base;
 105
 106         /* sequence required to disable watchdog */
 107         __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 108         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 109                 cpu_relax();
 110
 111         __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 112         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 113                 cpu_relax();
 114 }
 115
 116 static void omap_wdt_adjust_timeout(unsigned new_timeout)
 117 {
 118         if (new_timeout < TIMER_MARGIN_MIN)
 119                 new_timeout = TIMER_MARGIN_DEFAULT;
 120         if (new_timeout > TIMER_MARGIN_MAX)
 121                 new_timeout = TIMER_MARGIN_MAX;
 122         timer_margin = new_timeout;
 123 }
 124
 125 static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
 126 {
 127         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 128         void __iomem *base = wdev->base;
 129
 130         /* just count up at 32 KHz */
 131         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 132                 cpu_relax();
 133
 134         __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
 135         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 136                 cpu_relax();
 137 }
 138
 139 /*
 140  *      Allow only one task to hold it open
 141  */
 142 static int omap_wdt_open(struct inode *inode, struct file *file)
 143 {
 144         struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 145         void __iomem *base = wdev->base;
 146
 147         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 148                 return -EBUSY;
 149
 150         pm_runtime_get_sync(wdev->dev);
 151
 152         /* initialize prescaler */
 153         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 154                 cpu_relax();
 155
 156         __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 157         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 158                 cpu_relax();
 159
 160         file->private_data = (void *) wdev;
 161
 162         omap_wdt_set_timeout(wdev);
 163         omap_wdt_ping(wdev); /* trigger loading of new timeout value */
 164         omap_wdt_enable(wdev);
 165
 166         return nonseekable_open(inode, file);
 167 }
 168
 169 static int omap_wdt_release(struct inode *inode, struct file *file)
 170 {
 171         struct omap_wdt_dev *wdev = file->private_data;
 172
 173         /*
 174          *      Shut off the timer unless NOWAYOUT is defined.
 175          */
 176 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 177         omap_wdt_disable(wdev);
 178
 179         pm_runtime_put_sync(wdev->dev);
 180 #else
 181         pr_crit("Unexpected close, not stopping!\n");
 182 #endif
 183         wdev->omap_wdt_users = 0;
 184
 185         return 0;
 186 }
 187
 188 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 189                 size_t len, loff_t *ppos)
 190 {
 191         struct omap_wdt_dev *wdev = file->private_data;
 192
 193         /* Refresh LOAD_TIME. */
 194         if (len) {
 195                 spin_lock(&wdt_lock);
 196                 omap_wdt_ping(wdev);
 197                 spin_unlock(&wdt_lock);
 198         }
 199         return len;
 200 }
 201
 202 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 203                                                 unsigned long arg)
 204 {
 205         struct omap_wdt_dev *wdev;
 206         int new_margin;
 207         static const struct watchdog_info ident = {
 208                 .identity = "OMAP Watchdog",
 209                 .options = WDIOF_SETTIMEOUT,
 210                 .firmware_version = 0,
 211         };
 212
 213         wdev = file->private_data;
 214
 215         switch (cmd) {
 216         case WDIOC_GETSUPPORT:
 217                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 218                                 sizeof(ident));
 219         case WDIOC_GETSTATUS:
 220                 return put_user(0, (int __user *)arg);
 221         case WDIOC_GETBOOTSTATUS:
 222 #ifdef CONFIG_ARCH_OMAP1
 223                 if (cpu_is_omap16xx())
 224                         return put_user(__raw_readw(ARM_SYSST),
 225                                         (int __user *)arg);
 226 #endif
 227 #ifdef CONFIG_ARCH_OMAP2PLUS
 228                 if (cpu_is_omap24xx())
 229                         return put_user(omap_prcm_get_reset_sources(),
 230                                         (int __user *)arg);
 231 #endif
 232                 return put_user(0, (int __user *)arg);
 233         case WDIOC_KEEPALIVE:
 234                 spin_lock(&wdt_lock);
 235                 omap_wdt_ping(wdev);
 236                 spin_unlock(&wdt_lock);
 237                 return 0;
 238         case WDIOC_SETTIMEOUT:
 239                 if (get_user(new_margin, (int __user *)arg))
 240                         return -EFAULT;
 241                 omap_wdt_adjust_timeout(new_margin);
 242
 243                 spin_lock(&wdt_lock);
 244                 omap_wdt_disable(wdev);
 245                 omap_wdt_set_timeout(wdev);
 246                 omap_wdt_enable(wdev);
 247
 248                 omap_wdt_ping(wdev);
 249                 spin_unlock(&wdt_lock);
 250                 /* Fall */
 251         case WDIOC_GETTIMEOUT:
 252                 return put_user(timer_margin, (int __user *)arg);
 253         default:
 254                 return -ENOTTY;
 255         }
 256 }
 257
 258 static const struct file_operations omap_wdt_fops = {
 259         .owner = THIS_MODULE,
 260         .write = omap_wdt_write,
 261         .unlocked_ioctl = omap_wdt_ioctl,
 262         .open = omap_wdt_open,
 263         .release = omap_wdt_release,
 264         .llseek = no_llseek,
 265 };
 266
 267 static int __devinit omap_wdt_probe(struct platform_device *pdev)
 268 {
 269         struct resource *res, *mem;
 270         struct omap_wdt_dev *wdev;
 271         int ret;
 272
 273         /* reserve static register mappings */
 274         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 275         if (!res) {
 276                 ret = -ENOENT;
 277                 goto err_get_resource;
 278         }
 279
 280         if (omap_wdt_dev) {
 281                 ret = -EBUSY;
 282                 goto err_busy;
 283         }
 284
 285         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 286         if (!mem) {
 287                 ret = -EBUSY;
 288                 goto err_busy;
 289         }
 290
 291         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 292         if (!wdev) {
 293                 ret = -ENOMEM;
 294                 goto err_kzalloc;
 295         }
 296
 297         wdev->omap_wdt_users = 0;
 298         wdev->mem = mem;
 299         wdev->dev = &pdev->dev;
 300
 301         wdev->base = ioremap(res->start, resource_size(res));
 302         if (!wdev->base) {
 303                 ret = -ENOMEM;
 304                 goto err_ioremap;
 305         }
 306
 307         platform_set_drvdata(pdev, wdev);
 308
 309         pm_runtime_enable(wdev->dev);
 310         pm_runtime_get_sync(wdev->dev);
 311
 312         omap_wdt_disable(wdev);
 313         omap_wdt_adjust_timeout(timer_margin);
 314
 315         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 316         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 317         wdev->omap_wdt_miscdev.name = "watchdog";
 318         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 319
 320         ret = misc_register(&(wdev->omap_wdt_miscdev));
 321         if (ret)
 322                 goto err_misc;
 323
 324         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 325                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 326                 timer_margin);
 327
 328         pm_runtime_put_sync(wdev->dev);
 329
 330         omap_wdt_dev = pdev;
 331
 332         return 0;
 333
 334 err_misc:
 335         pm_runtime_disable(wdev->dev);
 336         platform_set_drvdata(pdev, NULL);
 337         iounmap(wdev->base);
 338
 339 err_ioremap:
 340         wdev->base = NULL;
 341         kfree(wdev);
 342
 343 err_kzalloc:
 344         release_mem_region(res->start, resource_size(res));
 345
 346 err_busy:
 347 err_get_resource:
 348
 349         return ret;
 350 }
 351
 352 static void omap_wdt_shutdown(struct platform_device *pdev)
 353 {
 354         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 355
 356         if (wdev->omap_wdt_users) {
 357                 omap_wdt_disable(wdev);
 358                 pm_runtime_put_sync(wdev->dev);
 359         }
 360 }
 361
 362 static int __devexit omap_wdt_remove(struct platform_device *pdev)
 363 {
 364         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 365         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 366
 367         pm_runtime_disable(wdev->dev);
 368         if (!res)
 369                 return -ENOENT;
 370
 371         misc_deregister(&(wdev->omap_wdt_miscdev));
 372         release_mem_region(res->start, resource_size(res));
 373         platform_set_drvdata(pdev, NULL);
 374
 375         iounmap(wdev->base);
 376
 377         kfree(wdev);
 378         omap_wdt_dev = NULL;
 379
 380         return 0;
 381 }
 382
 383 #ifdef  CONFIG_PM
 384
 385 /* REVISIT ... not clear this is the best way to handle system suspend; and
 386  * it's very inappropriate for selective device suspend (e.g. suspending this
 387  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 388  * may not play well enough with NOWAYOUT...
 389  */
 390
 391 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 392 {
 393         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 394
 395         if (wdev->omap_wdt_users) {
 396                 omap_wdt_disable(wdev);
 397                 pm_runtime_put_sync(wdev->dev);
 398         }
 399
 400         return 0;
 401 }
 402
 403 static int omap_wdt_resume(struct platform_device *pdev)
 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_enable(wdev);
 410                 omap_wdt_ping(wdev);
 411         }
 412
 413         return 0;
 414 }
 415
 416 #else
 417 #define omap_wdt_suspend        NULL
 418 #define omap_wdt_resume         NULL
 419 #endif
 420
 421 static const struct of_device_id omap_wdt_of_match[] = {
 422         { .compatible = "ti,omap3-wdt", },
 423         {},
 424 };
 425 MODULE_DEVICE_TABLE(of, omap_wdt_of_match);
 426
 427 static struct platform_driver omap_wdt_driver = {
 428         .probe          = omap_wdt_probe,
 429         .remove         = __devexit_p(omap_wdt_remove),
 430         .shutdown       = omap_wdt_shutdown,
 431         .suspend        = omap_wdt_suspend,
 432         .resume         = omap_wdt_resume,
 433         .driver         = {
 434                 .owner  = THIS_MODULE,
 435                 .name   = "omap_wdt",
 436                 .of_match_table = omap_wdt_of_match,
 437         },
 438 };
 439
 440 module_platform_driver(omap_wdt_driver);
 441
 442 MODULE_AUTHOR("George G. Davis");
 443 MODULE_LICENSE("GPL");
 444 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 445 MODULE_ALIAS("platform:omap_wdt");