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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 <mach/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_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
 176         omap_wdt_disable(wdev);
 177
 178         clk_disable(wdev->ick);
 179         clk_disable(wdev->fck);
 180 #else
 181         printk(KERN_CRIT "omap_wdt: 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                 if (cpu_is_omap16xx())
 223                         return put_user(__raw_readw(ARM_SYSST),
 224                                         (int __user *)arg);
 225                 if (cpu_is_omap24xx())
 226                         return put_user(omap_prcm_get_reset_sources(),
 227                                         (int __user *)arg);
 228         case WDIOC_KEEPALIVE:
 229                 spin_lock(&wdt_lock);
 230                 omap_wdt_ping(wdev);
 231                 spin_unlock(&wdt_lock);
 232                 return 0;
 233         case WDIOC_SETTIMEOUT:
 234                 if (get_user(new_margin, (int __user *)arg))
 235                         return -EFAULT;
 236                 omap_wdt_adjust_timeout(new_margin);
 237
 238                 spin_lock(&wdt_lock);
 239                 omap_wdt_disable(wdev);
 240                 omap_wdt_set_timeout(wdev);
 241                 omap_wdt_enable(wdev);
 242
 243                 omap_wdt_ping(wdev);
 244                 spin_unlock(&wdt_lock);
 245                 /* Fall */
 246         case WDIOC_GETTIMEOUT:
 247                 return put_user(timer_margin, (int __user *)arg);
 248         default:
 249                 return -ENOTTY;
 250         }
 251 }
 252
 253 static const struct file_operations omap_wdt_fops = {
 254         .owner = THIS_MODULE,
 255         .write = omap_wdt_write,
 256         .unlocked_ioctl = omap_wdt_ioctl,
 257         .open = omap_wdt_open,
 258         .release = omap_wdt_release,
 259 };
 260
 261 static int __init omap_wdt_probe(struct platform_device *pdev)
 262 {
 263         struct resource *res, *mem;
 264         struct omap_wdt_dev *wdev;
 265         int ret;
 266
 267         /* reserve static register mappings */
 268         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 269         if (!res) {
 270                 ret = -ENOENT;
 271                 goto err_get_resource;
 272         }
 273
 274         if (omap_wdt_dev) {
 275                 ret = -EBUSY;
 276                 goto err_busy;
 277         }
 278
 279         mem = request_mem_region(res->start, res->end - res->start + 1,
 280                                  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, res->end - res->start + 1);
 309         if (!wdev->base) {
 310                 ret = -ENOMEM;
 311                 goto err_ioremap;
 312         }
 313
 314         platform_set_drvdata(pdev, wdev);
 315
 316         omap_wdt_disable(wdev);
 317         omap_wdt_adjust_timeout(timer_margin);
 318
 319         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 320         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 321         wdev->omap_wdt_miscdev.name = "watchdog";
 322         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 323
 324         ret = misc_register(&(wdev->omap_wdt_miscdev));
 325         if (ret)
 326                 goto err_misc;
 327
 328         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 329                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 330                 timer_margin);
 331
 332         /* autogate OCP interface clock */
 333         __raw_writel(0x01, wdev->base + OMAP_WATCHDOG_SYS_CONFIG);
 334
 335         omap_wdt_dev = pdev;
 336
 337         return 0;
 338
 339 err_misc:
 340         platform_set_drvdata(pdev, NULL);
 341         iounmap(wdev->base);
 342
 343 err_ioremap:
 344         wdev->base = NULL;
 345
 346 err_clk:
 347         if (wdev->ick)
 348                 clk_put(wdev->ick);
 349         if (wdev->fck)
 350                 clk_put(wdev->fck);
 351         kfree(wdev);
 352
 353 err_kzalloc:
 354         release_mem_region(res->start, res->end - res->start + 1);
 355
 356 err_busy:
 357 err_get_resource:
 358
 359         return ret;
 360 }
 361
 362 static void omap_wdt_shutdown(struct platform_device *pdev)
 363 {
 364         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 365
 366         if (wdev->omap_wdt_users)
 367                 omap_wdt_disable(wdev);
 368 }
 369
 370 static int 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         if (!res)
 376                 return -ENOENT;
 377
 378         misc_deregister(&(wdev->omap_wdt_miscdev));
 379         release_mem_region(res->start, res->end - res->start + 1);
 380         platform_set_drvdata(pdev, NULL);
 381
 382         clk_put(wdev->ick);
 383         clk_put(wdev->fck);
 384         iounmap(wdev->base);
 385
 386         kfree(wdev);
 387         omap_wdt_dev = NULL;
 388
 389         return 0;
 390 }
 391
 392 #ifdef  CONFIG_PM
 393
 394 /* REVISIT ... not clear this is the best way to handle system suspend; and
 395  * it's very inappropriate for selective device suspend (e.g. suspending this
 396  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 397  * may not play well enough with NOWAYOUT...
 398  */
 399
 400 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 401 {
 402         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 403
 404         if (wdev->omap_wdt_users)
 405                 omap_wdt_disable(wdev);
 406
 407         return 0;
 408 }
 409
 410 static int omap_wdt_resume(struct platform_device *pdev)
 411 {
 412         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 413
 414         if (wdev->omap_wdt_users) {
 415                 omap_wdt_enable(wdev);
 416                 omap_wdt_ping(wdev);
 417         }
 418
 419         return 0;
 420 }
 421
 422 #else
 423 #define omap_wdt_suspend        NULL
 424 #define omap_wdt_resume         NULL
 425 #endif
 426
 427 static struct platform_driver omap_wdt_driver = {
 428         .probe          = omap_wdt_probe,
 429         .remove         = 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         },
 437 };
 438
 439 static int __init omap_wdt_init(void)
 440 {
 441         spin_lock_init(&wdt_lock);
 442         return platform_driver_register(&omap_wdt_driver);
 443 }
 444
 445 static void __exit omap_wdt_exit(void)
 446 {
 447         platform_driver_unregister(&omap_wdt_driver);
 448 }
 449
 450 module_init(omap_wdt_init);
 451 module_exit(omap_wdt_exit);
 452
 453 MODULE_AUTHOR("George G. Davis");
 454 MODULE_LICENSE("GPL");
 455 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 456 MODULE_ALIAS("platform:omap_wdt");