linux/drivers/watchdog/omap_wdt.c
<<
>>
Prefs
   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
  50static struct platform_device *omap_wdt_dev;
  51
  52static unsigned timer_margin;
  53module_param(timer_margin, uint, 0);
  54MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  55
  56static unsigned int wdt_trgr_pattern = 0x1234;
  57static spinlock_t wdt_lock;
  58
  59struct omap_wdt_dev {
  60        void __iomem    *base;          /* physical */
  61        struct device   *dev;
  62        int             omap_wdt_users;
  63        struct clk      *armwdt_ck;
  64        struct clk      *mpu_wdt_ick;
  65        struct clk      *mpu_wdt_fck;
  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        if (cpu_is_omap16xx())
 150                clk_enable(wdev->armwdt_ck);    /* Enable the clock */
 151
 152        if (cpu_is_omap24xx() || cpu_is_omap34xx()) {
 153                clk_enable(wdev->mpu_wdt_ick);    /* Enable the interface clock */
 154                clk_enable(wdev->mpu_wdt_fck);    /* Enable the functional clock */
 155        }
 156
 157        /* initialize prescaler */
 158        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 159                cpu_relax();
 160
 161        __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 162        while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
 163                cpu_relax();
 164
 165        file->private_data = (void *) wdev;
 166
 167        omap_wdt_set_timeout(wdev);
 168        omap_wdt_enable(wdev);
 169
 170        return nonseekable_open(inode, file);
 171}
 172
 173static int omap_wdt_release(struct inode *inode, struct file *file)
 174{
 175        struct omap_wdt_dev *wdev = file->private_data;
 176
 177        /*
 178         *      Shut off the timer unless NOWAYOUT is defined.
 179         */
 180#ifndef CONFIG_WATCHDOG_NOWAYOUT
 181
 182        omap_wdt_disable(wdev);
 183
 184        if (cpu_is_omap16xx())
 185                clk_disable(wdev->armwdt_ck);   /* Disable the clock */
 186
 187        if (cpu_is_omap24xx() || cpu_is_omap34xx()) {
 188                clk_disable(wdev->mpu_wdt_ick); /* Disable the clock */
 189                clk_disable(wdev->mpu_wdt_fck); /* Disable the clock */
 190        }
 191#else
 192        printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
 193#endif
 194        wdev->omap_wdt_users = 0;
 195
 196        return 0;
 197}
 198
 199static ssize_t omap_wdt_write(struct file *file, const char __user *data,
 200                size_t len, loff_t *ppos)
 201{
 202        struct omap_wdt_dev *wdev = file->private_data;
 203
 204        /* Refresh LOAD_TIME. */
 205        if (len) {
 206                spin_lock(&wdt_lock);
 207                omap_wdt_ping(wdev);
 208                spin_unlock(&wdt_lock);
 209        }
 210        return len;
 211}
 212
 213static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
 214                                                unsigned long arg)
 215{
 216        struct omap_wdt_dev *wdev;
 217        int new_margin;
 218        static const struct watchdog_info ident = {
 219                .identity = "OMAP Watchdog",
 220                .options = WDIOF_SETTIMEOUT,
 221                .firmware_version = 0,
 222        };
 223
 224        wdev = file->private_data;
 225
 226        switch (cmd) {
 227        case WDIOC_GETSUPPORT:
 228                return copy_to_user((struct watchdog_info __user *)arg, &ident,
 229                                sizeof(ident));
 230        case WDIOC_GETSTATUS:
 231                return put_user(0, (int __user *)arg);
 232        case WDIOC_GETBOOTSTATUS:
 233                if (cpu_is_omap16xx())
 234                        return put_user(__raw_readw(ARM_SYSST),
 235                                        (int __user *)arg);
 236                if (cpu_is_omap24xx())
 237                        return put_user(omap_prcm_get_reset_sources(),
 238                                        (int __user *)arg);
 239        case WDIOC_KEEPALIVE:
 240                spin_lock(&wdt_lock);
 241                omap_wdt_ping(wdev);
 242                spin_unlock(&wdt_lock);
 243                return 0;
 244        case WDIOC_SETTIMEOUT:
 245                if (get_user(new_margin, (int __user *)arg))
 246                        return -EFAULT;
 247                omap_wdt_adjust_timeout(new_margin);
 248
 249                spin_lock(&wdt_lock);
 250                omap_wdt_disable(wdev);
 251                omap_wdt_set_timeout(wdev);
 252                omap_wdt_enable(wdev);
 253
 254                omap_wdt_ping(wdev);
 255                spin_unlock(&wdt_lock);
 256                /* Fall */
 257        case WDIOC_GETTIMEOUT:
 258                return put_user(timer_margin, (int __user *)arg);
 259        default:
 260                return -ENOTTY;
 261        }
 262}
 263
 264static const struct file_operations omap_wdt_fops = {
 265        .owner = THIS_MODULE,
 266        .write = omap_wdt_write,
 267        .unlocked_ioctl = omap_wdt_ioctl,
 268        .open = omap_wdt_open,
 269        .release = omap_wdt_release,
 270};
 271
 272static int __init omap_wdt_probe(struct platform_device *pdev)
 273{
 274        struct resource *res, *mem;
 275        struct omap_wdt_dev *wdev;
 276        int ret;
 277
 278        /* reserve static register mappings */
 279        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 280        if (!res) {
 281                ret = -ENOENT;
 282                goto err_get_resource;
 283        }
 284
 285        if (omap_wdt_dev) {
 286                ret = -EBUSY;
 287                goto err_busy;
 288        }
 289
 290        mem = request_mem_region(res->start, res->end - res->start + 1,
 291                                 pdev->name);
 292        if (!mem) {
 293                ret = -EBUSY;
 294                goto err_busy;
 295        }
 296
 297        wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
 298        if (!wdev) {
 299                ret = -ENOMEM;
 300                goto err_kzalloc;
 301        }
 302
 303        wdev->omap_wdt_users = 0;
 304        wdev->mem = mem;
 305
 306        if (cpu_is_omap16xx()) {
 307                wdev->armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
 308                if (IS_ERR(wdev->armwdt_ck)) {
 309                        ret = PTR_ERR(wdev->armwdt_ck);
 310                        wdev->armwdt_ck = NULL;
 311                        goto err_clk;
 312                }
 313        }
 314
 315        if (cpu_is_omap24xx()) {
 316                wdev->mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
 317                if (IS_ERR(wdev->mpu_wdt_ick)) {
 318                        ret = PTR_ERR(wdev->mpu_wdt_ick);
 319                        wdev->mpu_wdt_ick = NULL;
 320                        goto err_clk;
 321                }
 322                wdev->mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
 323                if (IS_ERR(wdev->mpu_wdt_fck)) {
 324                        ret = PTR_ERR(wdev->mpu_wdt_fck);
 325                        wdev->mpu_wdt_fck = NULL;
 326                        goto err_clk;
 327                }
 328        }
 329
 330        if (cpu_is_omap34xx()) {
 331                wdev->mpu_wdt_ick = clk_get(&pdev->dev, "wdt2_ick");
 332                if (IS_ERR(wdev->mpu_wdt_ick)) {
 333                        ret = PTR_ERR(wdev->mpu_wdt_ick);
 334                        wdev->mpu_wdt_ick = NULL;
 335                        goto err_clk;
 336                }
 337                wdev->mpu_wdt_fck = clk_get(&pdev->dev, "wdt2_fck");
 338                if (IS_ERR(wdev->mpu_wdt_fck)) {
 339                        ret = PTR_ERR(wdev->mpu_wdt_fck);
 340                        wdev->mpu_wdt_fck = NULL;
 341                        goto err_clk;
 342                }
 343        }
 344        wdev->base = ioremap(res->start, res->end - res->start + 1);
 345        if (!wdev->base) {
 346                ret = -ENOMEM;
 347                goto err_ioremap;
 348        }
 349
 350        platform_set_drvdata(pdev, wdev);
 351
 352        omap_wdt_disable(wdev);
 353        omap_wdt_adjust_timeout(timer_margin);
 354
 355        wdev->omap_wdt_miscdev.parent = &pdev->dev;
 356        wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
 357        wdev->omap_wdt_miscdev.name = "watchdog";
 358        wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
 359
 360        ret = misc_register(&(wdev->omap_wdt_miscdev));
 361        if (ret)
 362                goto err_misc;
 363
 364        pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 365                __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 366                timer_margin);
 367
 368        /* autogate OCP interface clock */
 369        __raw_writel(0x01, wdev->base + OMAP_WATCHDOG_SYS_CONFIG);
 370
 371        omap_wdt_dev = pdev;
 372
 373        return 0;
 374
 375err_misc:
 376        platform_set_drvdata(pdev, NULL);
 377        iounmap(wdev->base);
 378
 379err_ioremap:
 380        wdev->base = NULL;
 381
 382err_clk:
 383        if (wdev->armwdt_ck)
 384                clk_put(wdev->armwdt_ck);
 385        if (wdev->mpu_wdt_ick)
 386                clk_put(wdev->mpu_wdt_ick);
 387        if (wdev->mpu_wdt_fck)
 388                clk_put(wdev->mpu_wdt_fck);
 389        kfree(wdev);
 390
 391err_kzalloc:
 392        release_mem_region(res->start, res->end - res->start + 1);
 393
 394err_busy:
 395err_get_resource:
 396
 397        return ret;
 398}
 399
 400static void omap_wdt_shutdown(struct platform_device *pdev)
 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
 408static int omap_wdt_remove(struct platform_device *pdev)
 409{
 410        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 411        struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 412
 413        if (!res)
 414                return -ENOENT;
 415
 416        misc_deregister(&(wdev->omap_wdt_miscdev));
 417        release_mem_region(res->start, res->end - res->start + 1);
 418        platform_set_drvdata(pdev, NULL);
 419
 420        if (wdev->armwdt_ck) {
 421                clk_put(wdev->armwdt_ck);
 422                wdev->armwdt_ck = NULL;
 423        }
 424
 425        if (wdev->mpu_wdt_ick) {
 426                clk_put(wdev->mpu_wdt_ick);
 427                wdev->mpu_wdt_ick = NULL;
 428        }
 429
 430        if (wdev->mpu_wdt_fck) {
 431                clk_put(wdev->mpu_wdt_fck);
 432                wdev->mpu_wdt_fck = NULL;
 433        }
 434        iounmap(wdev->base);
 435
 436        kfree(wdev);
 437        omap_wdt_dev = NULL;
 438
 439        return 0;
 440}
 441
 442#ifdef  CONFIG_PM
 443
 444/* REVISIT ... not clear this is the best way to handle system suspend; and
 445 * it's very inappropriate for selective device suspend (e.g. suspending this
 446 * through sysfs rather than by stopping the watchdog daemon).  Also, this
 447 * may not play well enough with NOWAYOUT...
 448 */
 449
 450static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 451{
 452        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 453
 454        if (wdev->omap_wdt_users)
 455                omap_wdt_disable(wdev);
 456
 457        return 0;
 458}
 459
 460static int omap_wdt_resume(struct platform_device *pdev)
 461{
 462        struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 463
 464        if (wdev->omap_wdt_users) {
 465                omap_wdt_enable(wdev);
 466                omap_wdt_ping(wdev);
 467        }
 468
 469        return 0;
 470}
 471
 472#else
 473#define omap_wdt_suspend        NULL
 474#define omap_wdt_resume         NULL
 475#endif
 476
 477static struct platform_driver omap_wdt_driver = {
 478        .probe          = omap_wdt_probe,
 479        .remove         = omap_wdt_remove,
 480        .shutdown       = omap_wdt_shutdown,
 481        .suspend        = omap_wdt_suspend,
 482        .resume         = omap_wdt_resume,
 483        .driver         = {
 484                .owner  = THIS_MODULE,
 485                .name   = "omap_wdt",
 486        },
 487};
 488
 489static int __init omap_wdt_init(void)
 490{
 491        spin_lock_init(&wdt_lock);
 492        return platform_driver_register(&omap_wdt_driver);
 493}
 494
 495static void __exit omap_wdt_exit(void)
 496{
 497        platform_driver_unregister(&omap_wdt_driver);
 498}
 499
 500module_init(omap_wdt_init);
 501module_exit(omap_wdt_exit);
 502
 503MODULE_AUTHOR("George G. Davis");
 504MODULE_LICENSE("GPL");
 505MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 506MODULE_ALIAS("platform:omap_wdt");
 507
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.