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/prcm.h>
  50
  51#include "omap_wdt.h"
  52
  53static struct platform_device *omap_wdt_dev;
  54
  55static unsigned timer_margin;
  56module_param(timer_margin, uint, 0);
  57MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  58
  59static unsigned int wdt_trgr_pattern = 0x1234;
  60static DEFINE_SPINLOCK(wdt_lock);
  61
  62struct omap_wdt_dev {
  63        void __iomem    *base;          /* physical */
  64        struct device   *dev;
  65        int             omap_wdt_users;
  66        struct resource *mem;
  67        struct miscdevice omap_wdt_miscdev;
  68};
  69
  70static 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
  87static 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
 101static 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
 115static 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
 124static 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 */
 141static 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        pm_runtime_get_sync(wdev->dev);
 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
 168static 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        omap_wdt_disable(wdev);
 177
 178        pm_runtime_put_sync(wdev->dev);
 179#else
 180        pr_crit("Unexpected close, not stopping!\n");
 181#endif
 182        wdev->omap_wdt_users = 0;
 183
 184        return 0;
 185}
 186
 187static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 188                size_t len, loff_t *ppos)
 189{
 190        struct omap_wdt_dev *wdev = file->private_data;
 191
 192        /* Refresh LOAD_TIME. */
 193        if (len) {
 194                spin_lock(&wdt_lock);
 195                omap_wdt_ping(wdev);
 196                spin_unlock(&wdt_lock);
 197        }
 198        return len;
 199}
 200
 201static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 202                                                unsigned long arg)
 203{
 204        struct omap_wdt_dev *wdev;
 205        int new_margin;
 206        static const struct watchdog_info ident = {
 207                .identity = "OMAP Watchdog",
 208                .options = WDIOF_SETTIMEOUT,
 209                .firmware_version = 0,
 210        };
 211
 212        wdev = file->private_data;
 213
 214        switch (cmd) {
 215        case WDIOC_GETSUPPORT:
 216                return copy_to_user((struct watchdog_info __user *)arg, &ident,
 217                                sizeof(ident));
 218        case WDIOC_GETSTATUS:
 219                return put_user(0, (int __user *)arg);
 220        case WDIOC_GETBOOTSTATUS:
 221                if (cpu_is_omap16xx())
 222                        return put_user(__raw_readw(ARM_SYSST),
 223                                        (int __user *)arg);
 224                if (cpu_is_omap24xx())
 225                        return put_user(omap_prcm_get_reset_sources(),
 226                                        (int __user *)arg);
 227                return put_user(0, (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
 253static 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        .llseek = no_llseek,
 260};
 261
 262static 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        wdev->dev = &pdev->dev;
 295
 296        wdev->base = ioremap(res->start, resource_size(res));
 297        if (!wdev->base) {
 298                ret = -ENOMEM;
 299                goto err_ioremap;
 300        }
 301
 302        platform_set_drvdata(pdev, wdev);
 303
 304        pm_runtime_enable(wdev->dev);
 305        pm_runtime_get_sync(wdev->dev);
 306
 307        omap_wdt_disable(wdev);
 308        omap_wdt_adjust_timeout(timer_margin);
 309
 310        wdev->omap_wdt_miscdev.parent = &pdev->dev;
 311        wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 312        wdev->omap_wdt_miscdev.name = "watchdog";
 313        wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 314
 315        ret = misc_register(&(wdev->omap_wdt_miscdev));
 316        if (ret)
 317                goto err_misc;
 318
 319        pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 320                __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 321                timer_margin);
 322
 323        pm_runtime_put_sync(wdev->dev);
 324
 325        omap_wdt_dev = pdev;
 326
 327        return 0;
 328
 329err_misc:
 330        pm_runtime_disable(wdev->dev);
 331        platform_set_drvdata(pdev, NULL);
 332        iounmap(wdev->base);
 333
 334err_ioremap:
 335        wdev->base = NULL;
 336        kfree(wdev);
 337
 338err_kzalloc:
 339        release_mem_region(res->start, resource_size(res));
 340
 341err_busy:
 342err_get_resource:
 343
 344        return ret;
 345}
 346
 347static void omap_wdt_shutdown(struct platform_device *pdev)
 348{
 349        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 350
 351        if (wdev->omap_wdt_users) {
 352                omap_wdt_disable(wdev);
 353                pm_runtime_put_sync(wdev->dev);
 354        }
 355}
 356
 357static int __devexit omap_wdt_remove(struct platform_device *pdev)
 358{
 359        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 360        struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 361
 362        pm_runtime_disable(wdev->dev);
 363        if (!res)
 364                return -ENOENT;
 365
 366        misc_deregister(&(wdev->omap_wdt_miscdev));
 367        release_mem_region(res->start, resource_size(res));
 368        platform_set_drvdata(pdev, NULL);
 369
 370        iounmap(wdev->base);
 371
 372        kfree(wdev);
 373        omap_wdt_dev = NULL;
 374
 375        return 0;
 376}
 377
 378#ifdef  CONFIG_PM
 379
 380/* REVISIT ... not clear this is the best way to handle system suspend; and
 381 * it's very inappropriate for selective device suspend (e.g. suspending this
 382 * through sysfs rather than by stopping the watchdog daemon).  Also, this
 383 * may not play well enough with NOWAYOUT...
 384 */
 385
 386static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 387{
 388        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 389
 390        if (wdev->omap_wdt_users) {
 391                omap_wdt_disable(wdev);
 392                pm_runtime_put_sync(wdev->dev);
 393        }
 394
 395        return 0;
 396}
 397
 398static int omap_wdt_resume(struct platform_device *pdev)
 399{
 400        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 401
 402        if (wdev->omap_wdt_users) {
 403                pm_runtime_get_sync(wdev->dev);
 404                omap_wdt_enable(wdev);
 405                omap_wdt_ping(wdev);
 406        }
 407
 408        return 0;
 409}
 410
 411#else
 412#define omap_wdt_suspend        NULL
 413#define omap_wdt_resume         NULL
 414#endif
 415
 416static const struct of_device_id omap_wdt_of_match[] = {
 417        { .compatible = "ti,omap3-wdt", },
 418        {},
 419};
 420MODULE_DEVICE_TABLE(of, omap_wdt_of_match);
 421
 422static struct platform_driver omap_wdt_driver = {
 423        .probe          = omap_wdt_probe,
 424        .remove         = __devexit_p(omap_wdt_remove),
 425        .shutdown       = omap_wdt_shutdown,
 426        .suspend        = omap_wdt_suspend,
 427        .resume         = omap_wdt_resume,
 428        .driver         = {
 429                .owner  = THIS_MODULE,
 430                .name   = "omap_wdt",
 431                .of_match_table = omap_wdt_of_match,
 432        },
 433};
 434
 435module_platform_driver(omap_wdt_driver);
 436
 437MODULE_AUTHOR("George G. Davis");
 438MODULE_LICENSE("GPL");
 439MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 440MODULE_ALIAS("platform:omap_wdt");
 441
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