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   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/clk.h>
  42 #include <linux/bitops.h>
  43 #include <linux/io.h>
  44 #include <linux/uaccess.h>
  45 #include <mach/hardware.h>
  46 #include <plat/prcm.h>
  47
  48 #include "omap_wdt.h"
  49
  50 static struct platform_device *omap_wdt_dev;
  51
  52 static unsigned timer_margin;
  53 module_param(timer_margin, uint, 0);
  54 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  55
  56 static unsigned int wdt_trgr_pattern = 0x1234;
  57 static spinlock_t wdt_lock;
  58
  59 struct omap_wdt_dev {
  60         void __iomem    *base;          /* physical */
  61         struct device   *dev;
  62         int             omap_wdt_users;
  63         struct clk      *ick;
  64         struct clk      *fck;
  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         clk_enable(wdev->ick);    /* Enable the interface clock */
 149         clk_enable(wdev->fck);    /* Enable the functional clock */
 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
 177         omap_wdt_disable(wdev);
 178
 179         clk_disable(wdev->ick);
 180         clk_disable(wdev->fck);
 181 #else
 182         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 183 #endif
 184         wdev->omap_wdt_users = 0;
 185
 186         return 0;
 187 }
 188
 189 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 190                 size_t len, loff_t *ppos)
 191 {
 192         struct omap_wdt_dev *wdev = file->private_data;
 193
 194         /* Refresh LOAD_TIME. */
 195         if (len) {
 196                 spin_lock(&wdt_lock);
 197                 omap_wdt_ping(wdev);
 198                 spin_unlock(&wdt_lock);
 199         }
 200         return len;
 201 }
 202
 203 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 204                                                 unsigned long arg)
 205 {
 206         struct omap_wdt_dev *wdev;
 207         int new_margin;
 208         static const struct watchdog_info ident = {
 209                 .identity = "OMAP Watchdog",
 210                 .options = WDIOF_SETTIMEOUT,
 211                 .firmware_version = 0,
 212         };
 213
 214         wdev = file->private_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 (cpu_is_omap16xx())
 224                         return put_user(__raw_readw(ARM_SYSST),
 225                                         (int __user *)arg);
 226                 if (cpu_is_omap24xx())
 227                         return put_user(omap_prcm_get_reset_sources(),
 228                                         (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 };
 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
 295         wdev->ick = clk_get(&pdev->dev, "ick");
 296         if (IS_ERR(wdev->ick)) {
 297                 ret = PTR_ERR(wdev->ick);
 298                 wdev->ick = NULL;
 299                 goto err_clk;
 300         }
 301         wdev->fck = clk_get(&pdev->dev, "fck");
 302         if (IS_ERR(wdev->fck)) {
 303                 ret = PTR_ERR(wdev->fck);
 304                 wdev->fck = NULL;
 305                 goto err_clk;
 306         }
 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         clk_enable(wdev->ick);
 317         clk_enable(wdev->fck);
 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         /* autogate OCP interface clock */
 336         __raw_writel(0x01, wdev->base + OMAP_WATCHDOG_SYS_CONFIG);
 337
 338         clk_disable(wdev->ick);
 339         clk_disable(wdev->fck);
 340
 341         omap_wdt_dev = pdev;
 342
 343         return 0;
 344
 345 err_misc:
 346         platform_set_drvdata(pdev, NULL);
 347         iounmap(wdev->base);
 348
 349 err_ioremap:
 350         wdev->base = NULL;
 351
 352 err_clk:
 353         if (wdev->ick)
 354                 clk_put(wdev->ick);
 355         if (wdev->fck)
 356                 clk_put(wdev->fck);
 357         kfree(wdev);
 358
 359 err_kzalloc:
 360         release_mem_region(res->start, resource_size(res));
 361
 362 err_busy:
 363 err_get_resource:
 364
 365         return ret;
 366 }
 367
 368 static void omap_wdt_shutdown(struct platform_device *pdev)
 369 {
 370         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 371
 372         if (wdev->omap_wdt_users)
 373                 omap_wdt_disable(wdev);
 374 }
 375
 376 static int __devexit omap_wdt_remove(struct platform_device *pdev)
 377 {
 378         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 379         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 380
 381         if (!res)
 382                 return -ENOENT;
 383
 384         misc_deregister(&(wdev->omap_wdt_miscdev));
 385         release_mem_region(res->start, resource_size(res));
 386         platform_set_drvdata(pdev, NULL);
 387
 388         clk_put(wdev->ick);
 389         clk_put(wdev->fck);
 390         iounmap(wdev->base);
 391
 392         kfree(wdev);
 393         omap_wdt_dev = NULL;
 394
 395         return 0;
 396 }
 397
 398 #ifdef  CONFIG_PM
 399
 400 /* REVISIT ... not clear this is the best way to handle system suspend; and
 401  * it's very inappropriate for selective device suspend (e.g. suspending this
 402  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 403  * may not play well enough with NOWAYOUT...
 404  */
 405
 406 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 407 {
 408         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 409
 410         if (wdev->omap_wdt_users)
 411                 omap_wdt_disable(wdev);
 412
 413         return 0;
 414 }
 415
 416 static int omap_wdt_resume(struct platform_device *pdev)
 417 {
 418         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 419
 420         if (wdev->omap_wdt_users) {
 421                 omap_wdt_enable(wdev);
 422                 omap_wdt_ping(wdev);
 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 struct platform_driver omap_wdt_driver = {
 434         .probe          = omap_wdt_probe,
 435         .remove         = __devexit_p(omap_wdt_remove),
 436         .shutdown       = omap_wdt_shutdown,
 437         .suspend        = omap_wdt_suspend,
 438         .resume         = omap_wdt_resume,
 439         .driver         = {
 440                 .owner  = THIS_MODULE,
 441                 .name   = "omap_wdt",
 442         },
 443 };
 444
 445 static int __init omap_wdt_init(void)
 446 {
 447         spin_lock_init(&wdt_lock);
 448         return platform_driver_register(&omap_wdt_driver);
 449 }
 450
 451 static void __exit omap_wdt_exit(void)
 452 {
 453         platform_driver_unregister(&omap_wdt_driver);
 454 }
 455
 456 module_init(omap_wdt_init);
 457 module_exit(omap_wdt_exit);
 458
 459 MODULE_AUTHOR("George G. Davis");
 460 MODULE_LICENSE("GPL");
 461 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 462 MODULE_ALIAS("platform:omap_wdt");