linux/drivers/watchdog/omap_wdt.c
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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/bitops.h>
  42#include <linux/io.h>
  43#include <linux/uaccess.h>
  44#include <linux/slab.h>
  45#include <linux/pm_runtime.h>
  46#include <mach/hardware.h>
  47#include <plat/prcm.h>
  48
  49#include "omap_wdt.h"
  50
  51static struct platform_device *omap_wdt_dev;
  52
  53static unsigned timer_margin;
  54module_param(timer_margin, uint, 0);
  55MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  56
  57static unsigned int wdt_trgr_pattern = 0x1234;
  58static spinlock_t wdt_lock;
  59
  60struct omap_wdt_dev {
  61        void __iomem    *base;          /* physical */
  62        struct device   *dev;
  63        int             omap_wdt_users;
  64        struct resource *mem;
  65        struct miscdevice omap_wdt_miscdev;
  66};
  67
  68static void omap_wdt_ping(struct omap_wdt_dev *wdev)
  69{
  70        void __iomem    *base = wdev->base;
  71
  72        /* wait for posted write to complete */
  73        while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  74                cpu_relax();
  75
  76        wdt_trgr_pattern = ~wdt_trgr_pattern;
  77        __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  78
  79        /* wait for posted write to complete */
  80        while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  81                cpu_relax();
  82        /* reloaded WCRR from WLDR */
  83}
  84
  85static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  86{
  87        void __iomem *base = wdev->base;
  88
  89        /* Sequence to enable the watchdog */
  90        __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
  91        while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  92                cpu_relax();
  93
  94        __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
  95        while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  96                cpu_relax();
  97}
  98
  99static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 100{
 101        void __iomem *base = wdev->base;
 102
 103        /* sequence required to disable watchdog */
 104        __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 105        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 106                cpu_relax();
 107
 108        __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 109        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 110                cpu_relax();
 111}
 112
 113static void omap_wdt_adjust_timeout(unsigned new_timeout)
 114{
 115        if (new_timeout < TIMER_MARGIN_MIN)
 116                new_timeout = TIMER_MARGIN_DEFAULT;
 117        if (new_timeout > TIMER_MARGIN_MAX)
 118                new_timeout = TIMER_MARGIN_MAX;
 119        timer_margin = new_timeout;
 120}
 121
 122static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
 123{
 124        u32 pre_margin = GET_WLDR_VAL(timer_margin);
 125        void __iomem *base = wdev->base;
 126
 127        /* just count up at 32 KHz */
 128        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 129                cpu_relax();
 130
 131        __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
 132        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 133                cpu_relax();
 134}
 135
 136/*
 137 *      Allow only one task to hold it open
 138 */
 139static int omap_wdt_open(struct inode *inode, struct file *file)
 140{
 141        struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 142        void __iomem *base = wdev->base;
 143
 144        if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 145                return -EBUSY;
 146
 147        pm_runtime_get_sync(wdev->dev);
 148
 149        /* initialize prescaler */
 150        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 151                cpu_relax();
 152
 153        __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 154        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 155                cpu_relax();
 156
 157        file->private_data = (void *) wdev;
 158
 159        omap_wdt_set_timeout(wdev);
 160        omap_wdt_ping(wdev); /* trigger loading of new timeout value */
 161        omap_wdt_enable(wdev);
 162
 163        return nonseekable_open(inode, file);
 164}
 165
 166static int omap_wdt_release(struct inode *inode, struct file *file)
 167{
 168        struct omap_wdt_dev *wdev = file->private_data;
 169
 170        /*
 171         *      Shut off the timer unless NOWAYOUT is defined.
 172         */
 173#ifndef CONFIG_WATCHDOG_NOWAYOUT
 174
 175        omap_wdt_disable(wdev);
 176
 177        pm_runtime_put_sync(wdev->dev);
 178#else
 179        printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 180#endif
 181        wdev->omap_wdt_users = 0;
 182
 183        return 0;
 184}
 185
 186static 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
 200static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 201                                                unsigned long arg)
 202{
 203        struct omap_wdt_dev *wdev;
 204        int new_margin;
 205        static const struct watchdog_info ident = {
 206                .identity = "OMAP Watchdog",
 207                .options = WDIOF_SETTIMEOUT,
 208                .firmware_version = 0,
 209        };
 210
 211        wdev = file->private_data;
 212
 213        switch (cmd) {
 214        case WDIOC_GETSUPPORT:
 215                return copy_to_user((struct watchdog_info __user *)arg, &ident,
 216                                sizeof(ident));
 217        case WDIOC_GETSTATUS:
 218                return put_user(0, (int __user *)arg);
 219        case WDIOC_GETBOOTSTATUS:
 220                if (cpu_is_omap16xx())
 221                        return put_user(__raw_readw(ARM_SYSST),
 222                                        (int __user *)arg);
 223                if (cpu_is_omap24xx())
 224                        return put_user(omap_prcm_get_reset_sources(),
 225                                        (int __user *)arg);
 226        case WDIOC_KEEPALIVE:
 227                spin_lock(&wdt_lock);
 228                omap_wdt_ping(wdev);
 229                spin_unlock(&wdt_lock);
 230                return 0;
 231        case WDIOC_SETTIMEOUT:
 232                if (get_user(new_margin, (int __user *)arg))
 233                        return -EFAULT;
 234                omap_wdt_adjust_timeout(new_margin);
 235
 236                spin_lock(&wdt_lock);
 237                omap_wdt_disable(wdev);
 238                omap_wdt_set_timeout(wdev);
 239                omap_wdt_enable(wdev);
 240
 241                omap_wdt_ping(wdev);
 242                spin_unlock(&wdt_lock);
 243                /* Fall */
 244        case WDIOC_GETTIMEOUT:
 245                return put_user(timer_margin, (int __user *)arg);
 246        default:
 247                return -ENOTTY;
 248        }
 249}
 250
 251static const struct file_operations omap_wdt_fops = {
 252        .owner = THIS_MODULE,
 253        .write = omap_wdt_write,
 254        .unlocked_ioctl = omap_wdt_ioctl,
 255        .open = omap_wdt_open,
 256        .release = omap_wdt_release,
 257        .llseek = no_llseek,
 258};
 259
 260static int __devinit omap_wdt_probe(struct platform_device *pdev)
 261{
 262        struct resource *res, *mem;
 263        struct omap_wdt_dev *wdev;
 264        int ret;
 265
 266        /* reserve static register mappings */
 267        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 268        if (!res) {
 269                ret = -ENOENT;
 270                goto err_get_resource;
 271        }
 272
 273        if (omap_wdt_dev) {
 274                ret = -EBUSY;
 275                goto err_busy;
 276        }
 277
 278        mem = request_mem_region(res->start, resource_size(res), pdev->name);
 279        if (!mem) {
 280                ret = -EBUSY;
 281                goto err_busy;
 282        }
 283
 284        wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 285        if (!wdev) {
 286                ret = -ENOMEM;
 287                goto err_kzalloc;
 288        }
 289
 290        wdev->omap_wdt_users = 0;
 291        wdev->mem = mem;
 292        wdev->dev = &pdev->dev;
 293
 294        wdev->base = ioremap(res->start, resource_size(res));
 295        if (!wdev->base) {
 296                ret = -ENOMEM;
 297                goto err_ioremap;
 298        }
 299
 300        platform_set_drvdata(pdev, wdev);
 301
 302        pm_runtime_enable(wdev->dev);
 303        pm_runtime_get_sync(wdev->dev);
 304
 305        omap_wdt_disable(wdev);
 306        omap_wdt_adjust_timeout(timer_margin);
 307
 308        wdev->omap_wdt_miscdev.parent = &pdev->dev;
 309        wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 310        wdev->omap_wdt_miscdev.name = "watchdog";
 311        wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 312
 313        ret = misc_register(&(wdev->omap_wdt_miscdev));
 314        if (ret)
 315                goto err_misc;
 316
 317        pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 318                __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 319                timer_margin);
 320
 321        pm_runtime_put_sync(wdev->dev);
 322
 323        omap_wdt_dev = pdev;
 324
 325        return 0;
 326
 327err_misc:
 328        platform_set_drvdata(pdev, NULL);
 329        iounmap(wdev->base);
 330
 331err_ioremap:
 332        wdev->base = NULL;
 333        kfree(wdev);
 334
 335err_kzalloc:
 336        release_mem_region(res->start, resource_size(res));
 337
 338err_busy:
 339err_get_resource:
 340
 341        return ret;
 342}
 343
 344static void omap_wdt_shutdown(struct platform_device *pdev)
 345{
 346        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 347
 348        if (wdev->omap_wdt_users)
 349                omap_wdt_disable(wdev);
 350}
 351
 352static int __devexit omap_wdt_remove(struct platform_device *pdev)
 353{
 354        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 355        struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 356
 357        if (!res)
 358                return -ENOENT;
 359
 360        misc_deregister(&(wdev->omap_wdt_miscdev));
 361        release_mem_region(res->start, resource_size(res));
 362        platform_set_drvdata(pdev, NULL);
 363
 364        iounmap(wdev->base);
 365
 366        kfree(wdev);
 367        omap_wdt_dev = NULL;
 368
 369        return 0;
 370}
 371
 372#ifdef  CONFIG_PM
 373
 374/* REVISIT ... not clear this is the best way to handle system suspend; and
 375 * it's very inappropriate for selective device suspend (e.g. suspending this
 376 * through sysfs rather than by stopping the watchdog daemon).  Also, this
 377 * may not play well enough with NOWAYOUT...
 378 */
 379
 380static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 381{
 382        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 383
 384        if (wdev->omap_wdt_users)
 385                omap_wdt_disable(wdev);
 386
 387        return 0;
 388}
 389
 390static int omap_wdt_resume(struct platform_device *pdev)
 391{
 392        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 393
 394        if (wdev->omap_wdt_users) {
 395                omap_wdt_enable(wdev);
 396                omap_wdt_ping(wdev);
 397        }
 398
 399        return 0;
 400}
 401
 402#else
 403#define omap_wdt_suspend        NULL
 404#define omap_wdt_resume         NULL
 405#endif
 406
 407static struct platform_driver omap_wdt_driver = {
 408        .probe          = omap_wdt_probe,
 409        .remove         = __devexit_p(omap_wdt_remove),
 410        .shutdown       = omap_wdt_shutdown,
 411        .suspend        = omap_wdt_suspend,
 412        .resume         = omap_wdt_resume,
 413        .driver         = {
 414                .owner  = THIS_MODULE,
 415                .name   = "omap_wdt",
 416        },
 417};
 418
 419static int __init omap_wdt_init(void)
 420{
 421        spin_lock_init(&wdt_lock);
 422        return platform_driver_register(&omap_wdt_driver);
 423}
 424
 425static void __exit omap_wdt_exit(void)
 426{
 427        platform_driver_unregister(&omap_wdt_driver);
 428}
 429
 430module_init(omap_wdt_init);
 431module_exit(omap_wdt_exit);
 432
 433MODULE_AUTHOR("George G. Davis");
 434MODULE_LICENSE("GPL");
 435MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 436MODULE_ALIAS("platform:omap_wdt");
 437