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#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 <mach/hardware.h>
  49#include <plat/cpu.h>
  50#include <plat/prcm.h>
  51
  52#include "omap_wdt.h"
  53
  54static struct platform_device *omap_wdt_dev;
  55
  56static unsigned timer_margin;
  57module_param(timer_margin, uint, 0);
  58MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  59
  60static unsigned int wdt_trgr_pattern = 0x1234;
  61static DEFINE_SPINLOCK(wdt_lock);
  62
  63struct omap_wdt_dev {
  64        void __iomem    *base;          /* physical */
  65        struct device   *dev;
  66        int             omap_wdt_users;
  67        struct resource *mem;
  68        struct miscdevice omap_wdt_miscdev;
  69};
  70
  71static void omap_wdt_ping(struct omap_wdt_dev *wdev)
  72{
  73        void __iomem    *base = wdev->base;
  74
  75        /* wait for posted write to complete */
  76        while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  77                cpu_relax();
  78
  79        wdt_trgr_pattern = ~wdt_trgr_pattern;
  80        __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  81
  82        /* wait for posted write to complete */
  83        while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
  84                cpu_relax();
  85        /* reloaded WCRR from WLDR */
  86}
  87
  88static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  89{
  90        void __iomem *base = wdev->base;
  91
  92        /* Sequence to enable the watchdog */
  93        __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
  94        while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  95                cpu_relax();
  96
  97        __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
  98        while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
  99                cpu_relax();
 100}
 101
 102static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 103{
 104        void __iomem *base = wdev->base;
 105
 106        /* sequence required to disable watchdog */
 107        __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 108        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 109                cpu_relax();
 110
 111        __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
 112        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
 113                cpu_relax();
 114}
 115
 116static void omap_wdt_adjust_timeout(unsigned new_timeout)
 117{
 118        if (new_timeout < TIMER_MARGIN_MIN)
 119                new_timeout = TIMER_MARGIN_DEFAULT;
 120        if (new_timeout > TIMER_MARGIN_MAX)
 121                new_timeout = TIMER_MARGIN_MAX;
 122        timer_margin = new_timeout;
 123}
 124
 125static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
 126{
 127        u32 pre_margin = GET_WLDR_VAL(timer_margin);
 128        void __iomem *base = wdev->base;
 129
 130        /* just count up at 32 KHz */
 131        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 132                cpu_relax();
 133
 134        __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
 135        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
 136                cpu_relax();
 137}
 138
 139/*
 140 *      Allow only one task to hold it open
 141 */
 142static int omap_wdt_open(struct inode *inode, struct file *file)
 143{
 144        struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
 145        void __iomem *base = wdev->base;
 146
 147        if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
 148                return -EBUSY;
 149
 150        pm_runtime_get_sync(wdev->dev);
 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
 169static 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        omap_wdt_disable(wdev);
 178
 179        pm_runtime_put_sync(wdev->dev);
 180#else
 181        pr_crit("Unexpected close, not stopping!\n");
 182#endif
 183        wdev->omap_wdt_users = 0;
 184
 185        return 0;
 186}
 187
 188static 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
 202static 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#ifdef CONFIG_ARCH_OMAP1
 223                if (cpu_is_omap16xx())
 224                        return put_user(__raw_readw(ARM_SYSST),
 225                                        (int __user *)arg);
 226#endif
 227#ifdef CONFIG_ARCH_OMAP2PLUS
 228                if (cpu_is_omap24xx())
 229                        return put_user(omap_prcm_get_reset_sources(),
 230                                        (int __user *)arg);
 231#endif
 232                return put_user(0, (int __user *)arg);
 233        case WDIOC_KEEPALIVE:
 234                spin_lock(&wdt_lock);
 235                omap_wdt_ping(wdev);
 236                spin_unlock(&wdt_lock);
 237                return 0;
 238        case WDIOC_SETTIMEOUT:
 239                if (get_user(new_margin, (int __user *)arg))
 240                        return -EFAULT;
 241                omap_wdt_adjust_timeout(new_margin);
 242
 243                spin_lock(&wdt_lock);
 244                omap_wdt_disable(wdev);
 245                omap_wdt_set_timeout(wdev);
 246                omap_wdt_enable(wdev);
 247
 248                omap_wdt_ping(wdev);
 249                spin_unlock(&wdt_lock);
 250                /* Fall */
 251        case WDIOC_GETTIMEOUT:
 252                return put_user(timer_margin, (int __user *)arg);
 253        default:
 254                return -ENOTTY;
 255        }
 256}
 257
 258static const struct file_operations omap_wdt_fops = {
 259        .owner = THIS_MODULE,
 260        .write = omap_wdt_write,
 261        .unlocked_ioctl = omap_wdt_ioctl,
 262        .open = omap_wdt_open,
 263        .release = omap_wdt_release,
 264        .llseek = no_llseek,
 265};
 266
 267static int __devinit omap_wdt_probe(struct platform_device *pdev)
 268{
 269        struct resource *res, *mem;
 270        struct omap_wdt_dev *wdev;
 271        int ret;
 272
 273        /* reserve static register mappings */
 274        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 275        if (!res) {
 276                ret = -ENOENT;
 277                goto err_get_resource;
 278        }
 279
 280        if (omap_wdt_dev) {
 281                ret = -EBUSY;
 282                goto err_busy;
 283        }
 284
 285        mem = request_mem_region(res->start, resource_size(res), pdev->name);
 286        if (!mem) {
 287                ret = -EBUSY;
 288                goto err_busy;
 289        }
 290
 291        wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 292        if (!wdev) {
 293                ret = -ENOMEM;
 294                goto err_kzalloc;
 295        }
 296
 297        wdev->omap_wdt_users = 0;
 298        wdev->mem = mem;
 299        wdev->dev = &pdev->dev;
 300
 301        wdev->base = ioremap(res->start, resource_size(res));
 302        if (!wdev->base) {
 303                ret = -ENOMEM;
 304                goto err_ioremap;
 305        }
 306
 307        platform_set_drvdata(pdev, wdev);
 308
 309        pm_runtime_enable(wdev->dev);
 310        pm_runtime_get_sync(wdev->dev);
 311
 312        omap_wdt_disable(wdev);
 313        omap_wdt_adjust_timeout(timer_margin);
 314
 315        wdev->omap_wdt_miscdev.parent = &pdev->dev;
 316        wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 317        wdev->omap_wdt_miscdev.name = "watchdog";
 318        wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 319
 320        ret = misc_register(&(wdev->omap_wdt_miscdev));
 321        if (ret)
 322                goto err_misc;
 323
 324        pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 325                __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 326                timer_margin);
 327
 328        pm_runtime_put_sync(wdev->dev);
 329
 330        omap_wdt_dev = pdev;
 331
 332        return 0;
 333
 334err_misc:
 335        pm_runtime_disable(wdev->dev);
 336        platform_set_drvdata(pdev, NULL);
 337        iounmap(wdev->base);
 338
 339err_ioremap:
 340        wdev->base = NULL;
 341        kfree(wdev);
 342
 343err_kzalloc:
 344        release_mem_region(res->start, resource_size(res));
 345
 346err_busy:
 347err_get_resource:
 348
 349        return ret;
 350}
 351
 352static void omap_wdt_shutdown(struct platform_device *pdev)
 353{
 354        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 355
 356        if (wdev->omap_wdt_users) {
 357                omap_wdt_disable(wdev);
 358                pm_runtime_put_sync(wdev->dev);
 359        }
 360}
 361
 362static int __devexit omap_wdt_remove(struct platform_device *pdev)
 363{
 364        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 365        struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 366
 367        pm_runtime_disable(wdev->dev);
 368        if (!res)
 369                return -ENOENT;
 370
 371        misc_deregister(&(wdev->omap_wdt_miscdev));
 372        release_mem_region(res->start, resource_size(res));
 373        platform_set_drvdata(pdev, NULL);
 374
 375        iounmap(wdev->base);
 376
 377        kfree(wdev);
 378        omap_wdt_dev = NULL;
 379
 380        return 0;
 381}
 382
 383#ifdef  CONFIG_PM
 384
 385/* REVISIT ... not clear this is the best way to handle system suspend; and
 386 * it's very inappropriate for selective device suspend (e.g. suspending this
 387 * through sysfs rather than by stopping the watchdog daemon).  Also, this
 388 * may not play well enough with NOWAYOUT...
 389 */
 390
 391static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 392{
 393        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 394
 395        if (wdev->omap_wdt_users) {
 396                omap_wdt_disable(wdev);
 397                pm_runtime_put_sync(wdev->dev);
 398        }
 399
 400        return 0;
 401}
 402
 403static int omap_wdt_resume(struct platform_device *pdev)
 404{
 405        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 406
 407        if (wdev->omap_wdt_users) {
 408                pm_runtime_get_sync(wdev->dev);
 409                omap_wdt_enable(wdev);
 410                omap_wdt_ping(wdev);
 411        }
 412
 413        return 0;
 414}
 415
 416#else
 417#define omap_wdt_suspend        NULL
 418#define omap_wdt_resume         NULL
 419#endif
 420
 421static const struct of_device_id omap_wdt_of_match[] = {
 422        { .compatible = "ti,omap3-wdt", },
 423        {},
 424};
 425MODULE_DEVICE_TABLE(of, omap_wdt_of_match);
 426
 427static struct platform_driver omap_wdt_driver = {
 428        .probe          = omap_wdt_probe,
 429        .remove         = __devexit_p(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                .of_match_table = omap_wdt_of_match,
 437        },
 438};
 439
 440module_platform_driver(omap_wdt_driver);
 441
 442MODULE_AUTHOR("George G. Davis");
 443MODULE_LICENSE("GPL");
 444MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 445MODULE_ALIAS("platform:omap_wdt");
 446
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