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/clk.h>
  42 #include <linux/bitops.h>
  43 #include <linux/io.h>
  44 #include <linux/uaccess.h>
  45 #include <linux/slab.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 spinlock_t wdt_lock;
  59
  60 struct omap_wdt_dev {
  61         void __iomem    *base;          /* physical */
  62         struct device   *dev;
  63         int             omap_wdt_users;
  64         struct clk      *ick;
  65         struct clk      *fck;
  66         struct resource *mem;
  67         struct miscdevice omap_wdt_miscdev;
  68 };
  69
  70 static void omap_wdt_ping(struct omap_wdt_dev *wdev)
  71 {
  72         void __iomem    *base = wdev->base;
  73
  74         /* wait for posted write to complete */
  75         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  76                 cpu_relax();
  77
  78         wdt_trgr_pattern = ~wdt_trgr_pattern;
  79         __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  80
  81         /* wait for posted write to complete */
  82         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  83                 cpu_relax();
  84         /* reloaded WCRR from WLDR */
  85 }
  86
  87 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  88 {
  89         void __iomem *base = wdev->base;
  90
  91         /* Sequence to enable the watchdog */
  92         __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
  93         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  94                 cpu_relax();
  95
  96         __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
  97         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  98                 cpu_relax();
  99 }
 100
 101 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 102 {
 103         void __iomem *base = wdev->base;
 104
 105         /* sequence required to disable watchdog */
 106         __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 107         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 108                 cpu_relax();
 109
 110         __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 111         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 112                 cpu_relax();
 113 }
 114
 115 static void omap_wdt_adjust_timeout(unsigned new_timeout)
 116 {
 117         if (new_timeout < TIMER_MARGIN_MIN)
 118                 new_timeout = TIMER_MARGIN_DEFAULT;
 119         if (new_timeout > TIMER_MARGIN_MAX)
 120                 new_timeout = TIMER_MARGIN_MAX;
 121         timer_margin = new_timeout;
 122 }
 123
 124 static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
 125 {
 126         u32 pre_margin = GET_WLDR_VAL(timer_margin);
 127         void __iomem *base = wdev->base;
 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
 138 /*
 139  *      Allow only one task to hold it open
 140  */
 141 static int omap_wdt_open(struct inode *inode, struct file *file)
 142 {
 143         struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 144         void __iomem *base = wdev->base;
 145
 146         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 147                 return -EBUSY;
 148
 149         clk_enable(wdev->ick);    /* Enable the interface clock */
 150         clk_enable(wdev->fck);    /* Enable the functional clock */
 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
 178         omap_wdt_disable(wdev);
 179
 180         clk_disable(wdev->ick);
 181         clk_disable(wdev->fck);
 182 #else
 183         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 184 #endif
 185         wdev->omap_wdt_users = 0;
 186
 187         return 0;
 188 }
 189
 190 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 191                 size_t len, loff_t *ppos)
 192 {
 193         struct omap_wdt_dev *wdev = file->private_data;
 194
 195         /* Refresh LOAD_TIME. */
 196         if (len) {
 197                 spin_lock(&wdt_lock);
 198                 omap_wdt_ping(wdev);
 199                 spin_unlock(&wdt_lock);
 200         }
 201         return len;
 202 }
 203
 204 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 205                                                 unsigned long arg)
 206 {
 207         struct omap_wdt_dev *wdev;
 208         int new_margin;
 209         static const struct watchdog_info ident = {
 210                 .identity = "OMAP Watchdog",
 211                 .options = WDIOF_SETTIMEOUT,
 212                 .firmware_version = 0,
 213         };
 214
 215         wdev = file->private_data;
 216
 217         switch (cmd) {
 218         case WDIOC_GETSUPPORT:
 219                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
 220                                 sizeof(ident));
 221         case WDIOC_GETSTATUS:
 222                 return put_user(0, (int __user *)arg);
 223         case WDIOC_GETBOOTSTATUS:
 224                 if (cpu_is_omap16xx())
 225                         return put_user(__raw_readw(ARM_SYSST),
 226                                         (int __user *)arg);
 227                 if (cpu_is_omap24xx())
 228                         return put_user(omap_prcm_get_reset_sources(),
 229                                         (int __user *)arg);
 230         case WDIOC_KEEPALIVE:
 231                 spin_lock(&wdt_lock);
 232                 omap_wdt_ping(wdev);
 233                 spin_unlock(&wdt_lock);
 234                 return 0;
 235         case WDIOC_SETTIMEOUT:
 236                 if (get_user(new_margin, (int __user *)arg))
 237                         return -EFAULT;
 238                 omap_wdt_adjust_timeout(new_margin);
 239
 240                 spin_lock(&wdt_lock);
 241                 omap_wdt_disable(wdev);
 242                 omap_wdt_set_timeout(wdev);
 243                 omap_wdt_enable(wdev);
 244
 245                 omap_wdt_ping(wdev);
 246                 spin_unlock(&wdt_lock);
 247                 /* Fall */
 248         case WDIOC_GETTIMEOUT:
 249                 return put_user(timer_margin, (int __user *)arg);
 250         default:
 251                 return -ENOTTY;
 252         }
 253 }
 254
 255 static const struct file_operations omap_wdt_fops = {
 256         .owner = THIS_MODULE,
 257         .write = omap_wdt_write,
 258         .unlocked_ioctl = omap_wdt_ioctl,
 259         .open = omap_wdt_open,
 260         .release = omap_wdt_release,
 261         .llseek = no_llseek,
 262 };
 263
 264 static int __devinit omap_wdt_probe(struct platform_device *pdev)
 265 {
 266         struct resource *res, *mem;
 267         struct omap_wdt_dev *wdev;
 268         int ret;
 269
 270         /* reserve static register mappings */
 271         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 272         if (!res) {
 273                 ret = -ENOENT;
 274                 goto err_get_resource;
 275         }
 276
 277         if (omap_wdt_dev) {
 278                 ret = -EBUSY;
 279                 goto err_busy;
 280         }
 281
 282         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 283         if (!mem) {
 284                 ret = -EBUSY;
 285                 goto err_busy;
 286         }
 287
 288         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 289         if (!wdev) {
 290                 ret = -ENOMEM;
 291                 goto err_kzalloc;
 292         }
 293
 294         wdev->omap_wdt_users = 0;
 295         wdev->mem = mem;
 296
 297         wdev->ick = clk_get(&pdev->dev, "ick");
 298         if (IS_ERR(wdev->ick)) {
 299                 ret = PTR_ERR(wdev->ick);
 300                 wdev->ick = NULL;
 301                 goto err_clk;
 302         }
 303         wdev->fck = clk_get(&pdev->dev, "fck");
 304         if (IS_ERR(wdev->fck)) {
 305                 ret = PTR_ERR(wdev->fck);
 306                 wdev->fck = NULL;
 307                 goto err_clk;
 308         }
 309
 310         wdev->base = ioremap(res->start, resource_size(res));
 311         if (!wdev->base) {
 312                 ret = -ENOMEM;
 313                 goto err_ioremap;
 314         }
 315
 316         platform_set_drvdata(pdev, wdev);
 317
 318         clk_enable(wdev->ick);
 319         clk_enable(wdev->fck);
 320
 321         omap_wdt_disable(wdev);
 322         omap_wdt_adjust_timeout(timer_margin);
 323
 324         wdev->omap_wdt_miscdev.parent = &pdev->dev;
 325         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 326         wdev->omap_wdt_miscdev.name = "watchdog";
 327         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 328
 329         ret = misc_register(&(wdev->omap_wdt_miscdev));
 330         if (ret)
 331                 goto err_misc;
 332
 333         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 334                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 335                 timer_margin);
 336
 337         /* autogate OCP interface clock */
 338         __raw_writel(0x01, wdev->base + OMAP_WATCHDOG_SYS_CONFIG);
 339
 340         clk_disable(wdev->ick);
 341         clk_disable(wdev->fck);
 342
 343         omap_wdt_dev = pdev;
 344
 345         return 0;
 346
 347 err_misc:
 348         platform_set_drvdata(pdev, NULL);
 349         iounmap(wdev->base);
 350
 351 err_ioremap:
 352         wdev->base = NULL;
 353
 354 err_clk:
 355         if (wdev->ick)
 356                 clk_put(wdev->ick);
 357         if (wdev->fck)
 358                 clk_put(wdev->fck);
 359         kfree(wdev);
 360
 361 err_kzalloc:
 362         release_mem_region(res->start, resource_size(res));
 363
 364 err_busy:
 365 err_get_resource:
 366
 367         return ret;
 368 }
 369
 370 static void omap_wdt_shutdown(struct platform_device *pdev)
 371 {
 372         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 373
 374         if (wdev->omap_wdt_users)
 375                 omap_wdt_disable(wdev);
 376 }
 377
 378 static int __devexit omap_wdt_remove(struct platform_device *pdev)
 379 {
 380         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 381         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 382
 383         if (!res)
 384                 return -ENOENT;
 385
 386         misc_deregister(&(wdev->omap_wdt_miscdev));
 387         release_mem_region(res->start, resource_size(res));
 388         platform_set_drvdata(pdev, NULL);
 389
 390         clk_put(wdev->ick);
 391         clk_put(wdev->fck);
 392         iounmap(wdev->base);
 393
 394         kfree(wdev);
 395         omap_wdt_dev = NULL;
 396
 397         return 0;
 398 }
 399
 400 #ifdef  CONFIG_PM
 401
 402 /* REVISIT ... not clear this is the best way to handle system suspend; and
 403  * it's very inappropriate for selective device suspend (e.g. suspending this
 404  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 405  * may not play well enough with NOWAYOUT...
 406  */
 407
 408 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 409 {
 410         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 411
 412         if (wdev->omap_wdt_users)
 413                 omap_wdt_disable(wdev);
 414
 415         return 0;
 416 }
 417
 418 static int omap_wdt_resume(struct platform_device *pdev)
 419 {
 420         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 421
 422         if (wdev->omap_wdt_users) {
 423                 omap_wdt_enable(wdev);
 424                 omap_wdt_ping(wdev);
 425         }
 426
 427         return 0;
 428 }
 429
 430 #else
 431 #define omap_wdt_suspend        NULL
 432 #define omap_wdt_resume         NULL
 433 #endif
 434
 435 static struct platform_driver omap_wdt_driver = {
 436         .probe          = omap_wdt_probe,
 437         .remove         = __devexit_p(omap_wdt_remove),
 438         .shutdown       = omap_wdt_shutdown,
 439         .suspend        = omap_wdt_suspend,
 440         .resume         = omap_wdt_resume,
 441         .driver         = {
 442                 .owner  = THIS_MODULE,
 443                 .name   = "omap_wdt",
 444         },
 445 };
 446
 447 static int __init omap_wdt_init(void)
 448 {
 449         spin_lock_init(&wdt_lock);
 450         return platform_driver_register(&omap_wdt_driver);
 451 }
 452
 453 static void __exit omap_wdt_exit(void)
 454 {
 455         platform_driver_unregister(&omap_wdt_driver);
 456 }
 457
 458 module_init(omap_wdt_init);
 459 module_exit(omap_wdt_exit);
 460
 461 MODULE_AUTHOR("George G. Davis");
 462 MODULE_LICENSE("GPL");
 463 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 464 MODULE_ALIAS("platform:omap_wdt");