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 <linux/platform_data/omap-wd-timer.h>
  49
  50 #include "omap_wdt.h"
  51
  52 static struct platform_device *omap_wdt_dev;
  53
  54 static unsigned timer_margin;
  55 module_param(timer_margin, uint, 0);
  56 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  57
  58 static unsigned int wdt_trgr_pattern = 0x1234;
  59 static DEFINE_SPINLOCK(wdt_lock);
  60
  61 struct omap_wdt_dev {
  62         void __iomem    *base;          /* physical */
  63         struct device   *dev;
  64         int             omap_wdt_users;
  65         struct resource *mem;
  66         struct miscdevice omap_wdt_miscdev;
  67 };
  68
  69 static void omap_wdt_ping(struct omap_wdt_dev *wdev)
  70 {
  71         void __iomem    *base = wdev->base;
  72
  73         /* wait for posted write to complete */
  74         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  75                 cpu_relax();
  76
  77         wdt_trgr_pattern = ~wdt_trgr_pattern;
  78         __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  79
  80         /* wait for posted write to complete */
  81         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  82                 cpu_relax();
  83         /* reloaded WCRR from WLDR */
  84 }
  85
  86 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  87 {
  88         void __iomem *base = wdev->base;
  89
  90         /* Sequence to enable the watchdog */
  91         __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
  92         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  93                 cpu_relax();
  94
  95         __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
  96         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  97                 cpu_relax();
  98 }
  99
 100 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 101 {
 102         void __iomem *base = wdev->base;
 103
 104         /* sequence required to disable watchdog */
 105         __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 106         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 107                 cpu_relax();
 108
 109         __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 110         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 111                 cpu_relax();
 112 }
 113
 114 static void omap_wdt_adjust_timeout(unsigned new_timeout)
 115 {
 116         if (new_timeout < TIMER_MARGIN_MIN)
 117                 new_timeout = TIMER_MARGIN_DEFAULT;
 118         if (new_timeout > TIMER_MARGIN_MAX)
 119                 new_timeout = TIMER_MARGIN_MAX;
 120         timer_margin = new_timeout;
 121 }
 122
 123 static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
 124 {
 125         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 126         void __iomem *base = wdev->base;
 127
 128         /* just count up at 32 KHz */
 129         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 130                 cpu_relax();
 131
 132         __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
 133         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 134                 cpu_relax();
 135 }
 136
 137 /*
 138  *      Allow only one task to hold it open
 139  */
 140 static int omap_wdt_open(struct inode *inode, struct file *file)
 141 {
 142         struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 143         void __iomem *base = wdev->base;
 144
 145         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 146                 return -EBUSY;
 147
 148         pm_runtime_get_sync(wdev->dev);
 149
 150         /* initialize prescaler */
 151         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 152                 cpu_relax();
 153
 154         __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 155         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 156                 cpu_relax();
 157
 158         file->private_data = (void *) wdev;
 159
 160         omap_wdt_set_timeout(wdev);
 161         omap_wdt_ping(wdev); /* trigger loading of new timeout value */
 162         omap_wdt_enable(wdev);
 163
 164         return nonseekable_open(inode, file);
 165 }
 166
 167 static int omap_wdt_release(struct inode *inode, struct file *file)
 168 {
 169         struct omap_wdt_dev *wdev = file->private_data;
 170
 171         /*
 172          *      Shut off the timer unless NOWAYOUT is defined.
 173          */
 174 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 175         omap_wdt_disable(wdev);
 176
 177         pm_runtime_put_sync(wdev->dev);
 178 #else
 179         pr_crit("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_wd_timer_platform_data *pdata;
 204         struct omap_wdt_dev *wdev;
 205         u32 rs;
 206         int new_margin, bs;
 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         pdata = wdev->dev->platform_data;
 215
 216         switch (cmd) {
 217         case WDIOC_GETSUPPORT:
 218                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 219                                 sizeof(ident));
 220         case WDIOC_GETSTATUS:
 221                 return put_user(0, (int __user *)arg);
 222         case WDIOC_GETBOOTSTATUS:
 223                 if (!pdata || !pdata->read_reset_sources)
 224                         return put_user(0, (int __user *)arg);
 225                 rs = pdata->read_reset_sources();
 226                 bs = (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT)) ?
 227                         WDIOF_CARDRESET : 0;
 228                 return put_user(bs, (int __user *)arg);
 229         case WDIOC_KEEPALIVE:
 230                 spin_lock(&wdt_lock);
 231                 omap_wdt_ping(wdev);
 232                 spin_unlock(&wdt_lock);
 233                 return 0;
 234         case WDIOC_SETTIMEOUT:
 235                 if (get_user(new_margin, (int __user *)arg))
 236                         return -EFAULT;
 237                 omap_wdt_adjust_timeout(new_margin);
 238
 239                 spin_lock(&wdt_lock);
 240                 omap_wdt_disable(wdev);
 241                 omap_wdt_set_timeout(wdev);
 242                 omap_wdt_enable(wdev);
 243
 244                 omap_wdt_ping(wdev);
 245                 spin_unlock(&wdt_lock);
 246                 /* Fall */
 247         case WDIOC_GETTIMEOUT:
 248                 return put_user(timer_margin, (int __user *)arg);
 249         default:
 250                 return -ENOTTY;
 251         }
 252 }
 253
 254 static const struct file_operations omap_wdt_fops = {
 255         .owner = THIS_MODULE,
 256         .write = omap_wdt_write,
 257         .unlocked_ioctl = omap_wdt_ioctl,
 258         .open = omap_wdt_open,
 259         .release = omap_wdt_release,
 260         .llseek = no_llseek,
 261 };
 262
 263 static int omap_wdt_probe(struct platform_device *pdev)
 264 {
 265         struct resource *res, *mem;
 266         struct omap_wdt_dev *wdev;
 267         int ret;
 268
 269         /* reserve static register mappings */
 270         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 271         if (!res) {
 272                 ret = -ENOENT;
 273                 goto err_get_resource;
 274         }
 275
 276         if (omap_wdt_dev) {
 277                 ret = -EBUSY;
 278                 goto err_busy;
 279         }
 280
 281         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 282         if (!mem) {
 283                 ret = -EBUSY;
 284                 goto err_busy;
 285         }
 286
 287         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 288         if (!wdev) {
 289                 ret = -ENOMEM;
 290                 goto err_kzalloc;
 291         }
 292
 293         wdev->omap_wdt_users = 0;
 294         wdev->mem = mem;
 295         wdev->dev = &pdev->dev;
 296
 297         wdev->base = ioremap(res->start, resource_size(res));
 298         if (!wdev->base) {
 299                 ret = -ENOMEM;
 300                 goto err_ioremap;
 301         }
 302
 303         platform_set_drvdata(pdev, wdev);
 304
 305         pm_runtime_enable(wdev->dev);
 306         pm_runtime_get_sync(wdev->dev);
 307
 308         omap_wdt_disable(wdev);
 309         omap_wdt_adjust_timeout(timer_margin);
 310
 311         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 312         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 313         wdev->omap_wdt_miscdev.name = "watchdog";
 314         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 315
 316         ret = misc_register(&(wdev->omap_wdt_miscdev));
 317         if (ret)
 318                 goto err_misc;
 319
 320         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 321                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 322                 timer_margin);
 323
 324         pm_runtime_put_sync(wdev->dev);
 325
 326         omap_wdt_dev = pdev;
 327
 328         return 0;
 329
 330 err_misc:
 331         pm_runtime_disable(wdev->dev);
 332         platform_set_drvdata(pdev, NULL);
 333         iounmap(wdev->base);
 334
 335 err_ioremap:
 336         wdev->base = NULL;
 337         kfree(wdev);
 338
 339 err_kzalloc:
 340         release_mem_region(res->start, resource_size(res));
 341
 342 err_busy:
 343 err_get_resource:
 344
 345         return ret;
 346 }
 347
 348 static void omap_wdt_shutdown(struct platform_device *pdev)
 349 {
 350         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 351
 352         if (wdev->omap_wdt_users) {
 353                 omap_wdt_disable(wdev);
 354                 pm_runtime_put_sync(wdev->dev);
 355         }
 356 }
 357
 358 static int omap_wdt_remove(struct platform_device *pdev)
 359 {
 360         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 361         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 362
 363         pm_runtime_disable(wdev->dev);
 364         if (!res)
 365                 return -ENOENT;
 366
 367         misc_deregister(&(wdev->omap_wdt_miscdev));
 368         release_mem_region(res->start, resource_size(res));
 369         platform_set_drvdata(pdev, NULL);
 370
 371         iounmap(wdev->base);
 372
 373         kfree(wdev);
 374         omap_wdt_dev = NULL;
 375
 376         return 0;
 377 }
 378
 379 #ifdef  CONFIG_PM
 380
 381 /* REVISIT ... not clear this is the best way to handle system suspend; and
 382  * it's very inappropriate for selective device suspend (e.g. suspending this
 383  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 384  * may not play well enough with NOWAYOUT...
 385  */
 386
 387 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 388 {
 389         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 390
 391         if (wdev->omap_wdt_users) {
 392                 omap_wdt_disable(wdev);
 393                 pm_runtime_put_sync(wdev->dev);
 394         }
 395
 396         return 0;
 397 }
 398
 399 static int omap_wdt_resume(struct platform_device *pdev)
 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_enable(wdev);
 406                 omap_wdt_ping(wdev);
 407         }
 408
 409         return 0;
 410 }
 411
 412 #else
 413 #define omap_wdt_suspend        NULL
 414 #define omap_wdt_resume         NULL
 415 #endif
 416
 417 static const struct of_device_id omap_wdt_of_match[] = {
 418         { .compatible = "ti,omap3-wdt", },
 419         {},
 420 };
 421 MODULE_DEVICE_TABLE(of, omap_wdt_of_match);
 422
 423 static struct platform_driver omap_wdt_driver = {
 424         .probe          = omap_wdt_probe,
 425         .remove         = omap_wdt_remove,
 426         .shutdown       = omap_wdt_shutdown,
 427         .suspend        = omap_wdt_suspend,
 428         .resume         = omap_wdt_resume,
 429         .driver         = {
 430                 .owner  = THIS_MODULE,
 431                 .name   = "omap_wdt",
 432                 .of_match_table = omap_wdt_of_match,
 433         },
 434 };
 435
 436 module_platform_driver(omap_wdt_driver);
 437
 438 MODULE_AUTHOR("George G. Davis");
 439 MODULE_LICENSE("GPL");
 440 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 441 MODULE_ALIAS("platform:omap_wdt");