linux/drivers/watchdog/s3c2410_wdt.c
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   1/*
   2 * Copyright (c) 2004 Simtec Electronics
   3 *      Ben Dooks <ben@simtec.co.uk>
   4 *
   5 * S3C2410 Watchdog Timer Support
   6 *
   7 * Based on, softdog.c by Alan Cox,
   8 *     (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License as published by
  12 * the Free Software Foundation; either version 2 of the License, or
  13 * (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 */
  20
  21#include <linux/module.h>
  22#include <linux/moduleparam.h>
  23#include <linux/types.h>
  24#include <linux/timer.h>
  25#include <linux/watchdog.h>
  26#include <linux/platform_device.h>
  27#include <linux/interrupt.h>
  28#include <linux/clk.h>
  29#include <linux/uaccess.h>
  30#include <linux/io.h>
  31#include <linux/cpufreq.h>
  32#include <linux/slab.h>
  33#include <linux/err.h>
  34#include <linux/of.h>
  35#include <linux/of_device.h>
  36#include <linux/mfd/syscon.h>
  37#include <linux/regmap.h>
  38#include <linux/delay.h>
  39
  40#define S3C2410_WTCON           0x00
  41#define S3C2410_WTDAT           0x04
  42#define S3C2410_WTCNT           0x08
  43#define S3C2410_WTCLRINT        0x0c
  44
  45#define S3C2410_WTCNT_MAXCNT    0xffff
  46
  47#define S3C2410_WTCON_RSTEN     (1 << 0)
  48#define S3C2410_WTCON_INTEN     (1 << 2)
  49#define S3C2410_WTCON_ENABLE    (1 << 5)
  50
  51#define S3C2410_WTCON_DIV16     (0 << 3)
  52#define S3C2410_WTCON_DIV32     (1 << 3)
  53#define S3C2410_WTCON_DIV64     (2 << 3)
  54#define S3C2410_WTCON_DIV128    (3 << 3)
  55
  56#define S3C2410_WTCON_MAXDIV    0x80
  57
  58#define S3C2410_WTCON_PRESCALE(x)       ((x) << 8)
  59#define S3C2410_WTCON_PRESCALE_MASK     (0xff << 8)
  60#define S3C2410_WTCON_PRESCALE_MAX      0xff
  61
  62#define S3C2410_WATCHDOG_ATBOOT         (0)
  63#define S3C2410_WATCHDOG_DEFAULT_TIME   (15)
  64
  65#define EXYNOS5_RST_STAT_REG_OFFSET             0x0404
  66#define EXYNOS5_WDT_DISABLE_REG_OFFSET          0x0408
  67#define EXYNOS5_WDT_MASK_RESET_REG_OFFSET       0x040c
  68#define QUIRK_HAS_PMU_CONFIG                    (1 << 0)
  69#define QUIRK_HAS_RST_STAT                      (1 << 1)
  70#define QUIRK_HAS_WTCLRINT_REG                  (1 << 2)
  71
  72/* These quirks require that we have a PMU register map */
  73#define QUIRKS_HAVE_PMUREG                      (QUIRK_HAS_PMU_CONFIG | \
  74                                                 QUIRK_HAS_RST_STAT)
  75
  76static bool nowayout    = WATCHDOG_NOWAYOUT;
  77static int tmr_margin;
  78static int tmr_atboot   = S3C2410_WATCHDOG_ATBOOT;
  79static int soft_noboot;
  80
  81module_param(tmr_margin,  int, 0);
  82module_param(tmr_atboot,  int, 0);
  83module_param(nowayout,   bool, 0);
  84module_param(soft_noboot, int, 0);
  85
  86MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. (default="
  87                __MODULE_STRING(S3C2410_WATCHDOG_DEFAULT_TIME) ")");
  88MODULE_PARM_DESC(tmr_atboot,
  89                "Watchdog is started at boot time if set to 1, default="
  90                        __MODULE_STRING(S3C2410_WATCHDOG_ATBOOT));
  91MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  92                        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  93MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default 0)");
  94
  95/**
  96 * struct s3c2410_wdt_variant - Per-variant config data
  97 *
  98 * @disable_reg: Offset in pmureg for the register that disables the watchdog
  99 * timer reset functionality.
 100 * @mask_reset_reg: Offset in pmureg for the register that masks the watchdog
 101 * timer reset functionality.
 102 * @mask_bit: Bit number for the watchdog timer in the disable register and the
 103 * mask reset register.
 104 * @rst_stat_reg: Offset in pmureg for the register that has the reset status.
 105 * @rst_stat_bit: Bit number in the rst_stat register indicating a watchdog
 106 * reset.
 107 * @quirks: A bitfield of quirks.
 108 */
 109
 110struct s3c2410_wdt_variant {
 111        int disable_reg;
 112        int mask_reset_reg;
 113        int mask_bit;
 114        int rst_stat_reg;
 115        int rst_stat_bit;
 116        u32 quirks;
 117};
 118
 119struct s3c2410_wdt {
 120        struct device           *dev;
 121        struct clk              *clock;
 122        void __iomem            *reg_base;
 123        unsigned int            count;
 124        spinlock_t              lock;
 125        unsigned long           wtcon_save;
 126        unsigned long           wtdat_save;
 127        struct watchdog_device  wdt_device;
 128        struct notifier_block   freq_transition;
 129        const struct s3c2410_wdt_variant *drv_data;
 130        struct regmap *pmureg;
 131};
 132
 133static const struct s3c2410_wdt_variant drv_data_s3c2410 = {
 134        .quirks = 0
 135};
 136
 137#ifdef CONFIG_OF
 138static const struct s3c2410_wdt_variant drv_data_s3c6410 = {
 139        .quirks = QUIRK_HAS_WTCLRINT_REG,
 140};
 141
 142static const struct s3c2410_wdt_variant drv_data_exynos5250  = {
 143        .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET,
 144        .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET,
 145        .mask_bit = 20,
 146        .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
 147        .rst_stat_bit = 20,
 148        .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
 149                  | QUIRK_HAS_WTCLRINT_REG,
 150};
 151
 152static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
 153        .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET,
 154        .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET,
 155        .mask_bit = 0,
 156        .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
 157        .rst_stat_bit = 9,
 158        .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
 159                  | QUIRK_HAS_WTCLRINT_REG,
 160};
 161
 162static const struct s3c2410_wdt_variant drv_data_exynos7 = {
 163        .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET,
 164        .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET,
 165        .mask_bit = 23,
 166        .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
 167        .rst_stat_bit = 23,     /* A57 WDTRESET */
 168        .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
 169                  | QUIRK_HAS_WTCLRINT_REG,
 170};
 171
 172static const struct of_device_id s3c2410_wdt_match[] = {
 173        { .compatible = "samsung,s3c2410-wdt",
 174          .data = &drv_data_s3c2410 },
 175        { .compatible = "samsung,s3c6410-wdt",
 176          .data = &drv_data_s3c6410 },
 177        { .compatible = "samsung,exynos5250-wdt",
 178          .data = &drv_data_exynos5250 },
 179        { .compatible = "samsung,exynos5420-wdt",
 180          .data = &drv_data_exynos5420 },
 181        { .compatible = "samsung,exynos7-wdt",
 182          .data = &drv_data_exynos7 },
 183        {},
 184};
 185MODULE_DEVICE_TABLE(of, s3c2410_wdt_match);
 186#endif
 187
 188static const struct platform_device_id s3c2410_wdt_ids[] = {
 189        {
 190                .name = "s3c2410-wdt",
 191                .driver_data = (unsigned long)&drv_data_s3c2410,
 192        },
 193        {}
 194};
 195MODULE_DEVICE_TABLE(platform, s3c2410_wdt_ids);
 196
 197/* functions */
 198
 199static inline unsigned int s3c2410wdt_max_timeout(struct clk *clock)
 200{
 201        unsigned long freq = clk_get_rate(clock);
 202
 203        return S3C2410_WTCNT_MAXCNT / (freq / (S3C2410_WTCON_PRESCALE_MAX + 1)
 204                                       / S3C2410_WTCON_MAXDIV);
 205}
 206
 207static inline struct s3c2410_wdt *freq_to_wdt(struct notifier_block *nb)
 208{
 209        return container_of(nb, struct s3c2410_wdt, freq_transition);
 210}
 211
 212static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask)
 213{
 214        int ret;
 215        u32 mask_val = 1 << wdt->drv_data->mask_bit;
 216        u32 val = 0;
 217
 218        /* No need to do anything if no PMU CONFIG needed */
 219        if (!(wdt->drv_data->quirks & QUIRK_HAS_PMU_CONFIG))
 220                return 0;
 221
 222        if (mask)
 223                val = mask_val;
 224
 225        ret = regmap_update_bits(wdt->pmureg,
 226                        wdt->drv_data->disable_reg,
 227                        mask_val, val);
 228        if (ret < 0)
 229                goto error;
 230
 231        ret = regmap_update_bits(wdt->pmureg,
 232                        wdt->drv_data->mask_reset_reg,
 233                        mask_val, val);
 234 error:
 235        if (ret < 0)
 236                dev_err(wdt->dev, "failed to update reg(%d)\n", ret);
 237
 238        return ret;
 239}
 240
 241static int s3c2410wdt_keepalive(struct watchdog_device *wdd)
 242{
 243        struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 244
 245        spin_lock(&wdt->lock);
 246        writel(wdt->count, wdt->reg_base + S3C2410_WTCNT);
 247        spin_unlock(&wdt->lock);
 248
 249        return 0;
 250}
 251
 252static void __s3c2410wdt_stop(struct s3c2410_wdt *wdt)
 253{
 254        unsigned long wtcon;
 255
 256        wtcon = readl(wdt->reg_base + S3C2410_WTCON);
 257        wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
 258        writel(wtcon, wdt->reg_base + S3C2410_WTCON);
 259}
 260
 261static int s3c2410wdt_stop(struct watchdog_device *wdd)
 262{
 263        struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 264
 265        spin_lock(&wdt->lock);
 266        __s3c2410wdt_stop(wdt);
 267        spin_unlock(&wdt->lock);
 268
 269        return 0;
 270}
 271
 272static int s3c2410wdt_start(struct watchdog_device *wdd)
 273{
 274        unsigned long wtcon;
 275        struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 276
 277        spin_lock(&wdt->lock);
 278
 279        __s3c2410wdt_stop(wdt);
 280
 281        wtcon = readl(wdt->reg_base + S3C2410_WTCON);
 282        wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
 283
 284        if (soft_noboot) {
 285                wtcon |= S3C2410_WTCON_INTEN;
 286                wtcon &= ~S3C2410_WTCON_RSTEN;
 287        } else {
 288                wtcon &= ~S3C2410_WTCON_INTEN;
 289                wtcon |= S3C2410_WTCON_RSTEN;
 290        }
 291
 292        dev_dbg(wdt->dev, "Starting watchdog: count=0x%08x, wtcon=%08lx\n",
 293                wdt->count, wtcon);
 294
 295        writel(wdt->count, wdt->reg_base + S3C2410_WTDAT);
 296        writel(wdt->count, wdt->reg_base + S3C2410_WTCNT);
 297        writel(wtcon, wdt->reg_base + S3C2410_WTCON);
 298        spin_unlock(&wdt->lock);
 299
 300        return 0;
 301}
 302
 303static inline int s3c2410wdt_is_running(struct s3c2410_wdt *wdt)
 304{
 305        return readl(wdt->reg_base + S3C2410_WTCON) & S3C2410_WTCON_ENABLE;
 306}
 307
 308static int s3c2410wdt_set_heartbeat(struct watchdog_device *wdd,
 309                                    unsigned int timeout)
 310{
 311        struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 312        unsigned long freq = clk_get_rate(wdt->clock);
 313        unsigned int count;
 314        unsigned int divisor = 1;
 315        unsigned long wtcon;
 316
 317        if (timeout < 1)
 318                return -EINVAL;
 319
 320        freq = DIV_ROUND_UP(freq, 128);
 321        count = timeout * freq;
 322
 323        dev_dbg(wdt->dev, "Heartbeat: count=%d, timeout=%d, freq=%lu\n",
 324                count, timeout, freq);
 325
 326        /* if the count is bigger than the watchdog register,
 327           then work out what we need to do (and if) we can
 328           actually make this value
 329        */
 330
 331        if (count >= 0x10000) {
 332                divisor = DIV_ROUND_UP(count, 0xffff);
 333
 334                if (divisor > 0x100) {
 335                        dev_err(wdt->dev, "timeout %d too big\n", timeout);
 336                        return -EINVAL;
 337                }
 338        }
 339
 340        dev_dbg(wdt->dev, "Heartbeat: timeout=%d, divisor=%d, count=%d (%08x)\n",
 341                timeout, divisor, count, DIV_ROUND_UP(count, divisor));
 342
 343        count = DIV_ROUND_UP(count, divisor);
 344        wdt->count = count;
 345
 346        /* update the pre-scaler */
 347        wtcon = readl(wdt->reg_base + S3C2410_WTCON);
 348        wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
 349        wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
 350
 351        writel(count, wdt->reg_base + S3C2410_WTDAT);
 352        writel(wtcon, wdt->reg_base + S3C2410_WTCON);
 353
 354        wdd->timeout = (count * divisor) / freq;
 355
 356        return 0;
 357}
 358
 359static int s3c2410wdt_restart(struct watchdog_device *wdd, unsigned long action,
 360                              void *data)
 361{
 362        struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 363        void __iomem *wdt_base = wdt->reg_base;
 364
 365        /* disable watchdog, to be safe  */
 366        writel(0, wdt_base + S3C2410_WTCON);
 367
 368        /* put initial values into count and data */
 369        writel(0x80, wdt_base + S3C2410_WTCNT);
 370        writel(0x80, wdt_base + S3C2410_WTDAT);
 371
 372        /* set the watchdog to go and reset... */
 373        writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 |
 374                S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20),
 375                wdt_base + S3C2410_WTCON);
 376
 377        /* wait for reset to assert... */
 378        mdelay(500);
 379
 380        return 0;
 381}
 382
 383#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
 384
 385static const struct watchdog_info s3c2410_wdt_ident = {
 386        .options          =     OPTIONS,
 387        .firmware_version =     0,
 388        .identity         =     "S3C2410 Watchdog",
 389};
 390
 391static const struct watchdog_ops s3c2410wdt_ops = {
 392        .owner = THIS_MODULE,
 393        .start = s3c2410wdt_start,
 394        .stop = s3c2410wdt_stop,
 395        .ping = s3c2410wdt_keepalive,
 396        .set_timeout = s3c2410wdt_set_heartbeat,
 397        .restart = s3c2410wdt_restart,
 398};
 399
 400static const struct watchdog_device s3c2410_wdd = {
 401        .info = &s3c2410_wdt_ident,
 402        .ops = &s3c2410wdt_ops,
 403        .timeout = S3C2410_WATCHDOG_DEFAULT_TIME,
 404};
 405
 406/* interrupt handler code */
 407
 408static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
 409{
 410        struct s3c2410_wdt *wdt = platform_get_drvdata(param);
 411
 412        dev_info(wdt->dev, "watchdog timer expired (irq)\n");
 413
 414        s3c2410wdt_keepalive(&wdt->wdt_device);
 415
 416        if (wdt->drv_data->quirks & QUIRK_HAS_WTCLRINT_REG)
 417                writel(0x1, wdt->reg_base + S3C2410_WTCLRINT);
 418
 419        return IRQ_HANDLED;
 420}
 421
 422#ifdef CONFIG_ARM_S3C24XX_CPUFREQ
 423
 424static int s3c2410wdt_cpufreq_transition(struct notifier_block *nb,
 425                                          unsigned long val, void *data)
 426{
 427        int ret;
 428        struct s3c2410_wdt *wdt = freq_to_wdt(nb);
 429
 430        if (!s3c2410wdt_is_running(wdt))
 431                goto done;
 432
 433        if (val == CPUFREQ_PRECHANGE) {
 434                /* To ensure that over the change we don't cause the
 435                 * watchdog to trigger, we perform an keep-alive if
 436                 * the watchdog is running.
 437                 */
 438
 439                s3c2410wdt_keepalive(&wdt->wdt_device);
 440        } else if (val == CPUFREQ_POSTCHANGE) {
 441                s3c2410wdt_stop(&wdt->wdt_device);
 442
 443                ret = s3c2410wdt_set_heartbeat(&wdt->wdt_device,
 444                                                wdt->wdt_device.timeout);
 445
 446                if (ret >= 0)
 447                        s3c2410wdt_start(&wdt->wdt_device);
 448                else
 449                        goto err;
 450        }
 451
 452done:
 453        return 0;
 454
 455 err:
 456        dev_err(wdt->dev, "cannot set new value for timeout %d\n",
 457                                wdt->wdt_device.timeout);
 458        return ret;
 459}
 460
 461static inline int s3c2410wdt_cpufreq_register(struct s3c2410_wdt *wdt)
 462{
 463        wdt->freq_transition.notifier_call = s3c2410wdt_cpufreq_transition;
 464
 465        return cpufreq_register_notifier(&wdt->freq_transition,
 466                                         CPUFREQ_TRANSITION_NOTIFIER);
 467}
 468
 469static inline void s3c2410wdt_cpufreq_deregister(struct s3c2410_wdt *wdt)
 470{
 471        wdt->freq_transition.notifier_call = s3c2410wdt_cpufreq_transition;
 472
 473        cpufreq_unregister_notifier(&wdt->freq_transition,
 474                                    CPUFREQ_TRANSITION_NOTIFIER);
 475}
 476
 477#else
 478
 479static inline int s3c2410wdt_cpufreq_register(struct s3c2410_wdt *wdt)
 480{
 481        return 0;
 482}
 483
 484static inline void s3c2410wdt_cpufreq_deregister(struct s3c2410_wdt *wdt)
 485{
 486}
 487#endif
 488
 489static inline unsigned int s3c2410wdt_get_bootstatus(struct s3c2410_wdt *wdt)
 490{
 491        unsigned int rst_stat;
 492        int ret;
 493
 494        if (!(wdt->drv_data->quirks & QUIRK_HAS_RST_STAT))
 495                return 0;
 496
 497        ret = regmap_read(wdt->pmureg, wdt->drv_data->rst_stat_reg, &rst_stat);
 498        if (ret)
 499                dev_warn(wdt->dev, "Couldn't get RST_STAT register\n");
 500        else if (rst_stat & BIT(wdt->drv_data->rst_stat_bit))
 501                return WDIOF_CARDRESET;
 502
 503        return 0;
 504}
 505
 506static inline const struct s3c2410_wdt_variant *
 507s3c2410_get_wdt_drv_data(struct platform_device *pdev)
 508{
 509        const struct s3c2410_wdt_variant *variant;
 510
 511        variant = of_device_get_match_data(&pdev->dev);
 512        if (!variant) {
 513                /* Device matched by platform_device_id */
 514                variant = (struct s3c2410_wdt_variant *)
 515                           platform_get_device_id(pdev)->driver_data;
 516        }
 517
 518        return variant;
 519}
 520
 521static int s3c2410wdt_probe(struct platform_device *pdev)
 522{
 523        struct device *dev = &pdev->dev;
 524        struct s3c2410_wdt *wdt;
 525        struct resource *wdt_mem;
 526        struct resource *wdt_irq;
 527        unsigned int wtcon;
 528        int started = 0;
 529        int ret;
 530
 531        wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 532        if (!wdt)
 533                return -ENOMEM;
 534
 535        wdt->dev = dev;
 536        spin_lock_init(&wdt->lock);
 537        wdt->wdt_device = s3c2410_wdd;
 538
 539        wdt->drv_data = s3c2410_get_wdt_drv_data(pdev);
 540        if (wdt->drv_data->quirks & QUIRKS_HAVE_PMUREG) {
 541                wdt->pmureg = syscon_regmap_lookup_by_phandle(dev->of_node,
 542                                                "samsung,syscon-phandle");
 543                if (IS_ERR(wdt->pmureg)) {
 544                        dev_err(dev, "syscon regmap lookup failed.\n");
 545                        return PTR_ERR(wdt->pmureg);
 546                }
 547        }
 548
 549        wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 550        if (wdt_irq == NULL) {
 551                dev_err(dev, "no irq resource specified\n");
 552                ret = -ENOENT;
 553                goto err;
 554        }
 555
 556        /* get the memory region for the watchdog timer */
 557        wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 558        wdt->reg_base = devm_ioremap_resource(dev, wdt_mem);
 559        if (IS_ERR(wdt->reg_base)) {
 560                ret = PTR_ERR(wdt->reg_base);
 561                goto err;
 562        }
 563
 564        wdt->clock = devm_clk_get(dev, "watchdog");
 565        if (IS_ERR(wdt->clock)) {
 566                dev_err(dev, "failed to find watchdog clock source\n");
 567                ret = PTR_ERR(wdt->clock);
 568                goto err;
 569        }
 570
 571        ret = clk_prepare_enable(wdt->clock);
 572        if (ret < 0) {
 573                dev_err(dev, "failed to enable clock\n");
 574                return ret;
 575        }
 576
 577        wdt->wdt_device.min_timeout = 1;
 578        wdt->wdt_device.max_timeout = s3c2410wdt_max_timeout(wdt->clock);
 579
 580        ret = s3c2410wdt_cpufreq_register(wdt);
 581        if (ret < 0) {
 582                dev_err(dev, "failed to register cpufreq\n");
 583                goto err_clk;
 584        }
 585
 586        watchdog_set_drvdata(&wdt->wdt_device, wdt);
 587
 588        /* see if we can actually set the requested timer margin, and if
 589         * not, try the default value */
 590
 591        watchdog_init_timeout(&wdt->wdt_device, tmr_margin, dev);
 592        ret = s3c2410wdt_set_heartbeat(&wdt->wdt_device,
 593                                        wdt->wdt_device.timeout);
 594        if (ret) {
 595                started = s3c2410wdt_set_heartbeat(&wdt->wdt_device,
 596                                        S3C2410_WATCHDOG_DEFAULT_TIME);
 597
 598                if (started == 0)
 599                        dev_info(dev,
 600                                 "tmr_margin value out of range, default %d used\n",
 601                                 S3C2410_WATCHDOG_DEFAULT_TIME);
 602                else
 603                        dev_info(dev, "default timer value is out of range, cannot start\n");
 604        }
 605
 606        ret = devm_request_irq(dev, wdt_irq->start, s3c2410wdt_irq, 0,
 607                                pdev->name, pdev);
 608        if (ret != 0) {
 609                dev_err(dev, "failed to install irq (%d)\n", ret);
 610                goto err_cpufreq;
 611        }
 612
 613        watchdog_set_nowayout(&wdt->wdt_device, nowayout);
 614        watchdog_set_restart_priority(&wdt->wdt_device, 128);
 615
 616        wdt->wdt_device.bootstatus = s3c2410wdt_get_bootstatus(wdt);
 617        wdt->wdt_device.parent = dev;
 618
 619        ret = watchdog_register_device(&wdt->wdt_device);
 620        if (ret) {
 621                dev_err(dev, "cannot register watchdog (%d)\n", ret);
 622                goto err_cpufreq;
 623        }
 624
 625        ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
 626        if (ret < 0)
 627                goto err_unregister;
 628
 629        if (tmr_atboot && started == 0) {
 630                dev_info(dev, "starting watchdog timer\n");
 631                s3c2410wdt_start(&wdt->wdt_device);
 632        } else if (!tmr_atboot) {
 633                /* if we're not enabling the watchdog, then ensure it is
 634                 * disabled if it has been left running from the bootloader
 635                 * or other source */
 636
 637                s3c2410wdt_stop(&wdt->wdt_device);
 638        }
 639
 640        platform_set_drvdata(pdev, wdt);
 641
 642        /* print out a statement of readiness */
 643
 644        wtcon = readl(wdt->reg_base + S3C2410_WTCON);
 645
 646        dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n",
 647                 (wtcon & S3C2410_WTCON_ENABLE) ?  "" : "in",
 648                 (wtcon & S3C2410_WTCON_RSTEN) ? "en" : "dis",
 649                 (wtcon & S3C2410_WTCON_INTEN) ? "en" : "dis");
 650
 651        return 0;
 652
 653 err_unregister:
 654        watchdog_unregister_device(&wdt->wdt_device);
 655
 656 err_cpufreq:
 657        s3c2410wdt_cpufreq_deregister(wdt);
 658
 659 err_clk:
 660        clk_disable_unprepare(wdt->clock);
 661
 662 err:
 663        return ret;
 664}
 665
 666static int s3c2410wdt_remove(struct platform_device *dev)
 667{
 668        int ret;
 669        struct s3c2410_wdt *wdt = platform_get_drvdata(dev);
 670
 671        ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
 672        if (ret < 0)
 673                return ret;
 674
 675        watchdog_unregister_device(&wdt->wdt_device);
 676
 677        s3c2410wdt_cpufreq_deregister(wdt);
 678
 679        clk_disable_unprepare(wdt->clock);
 680
 681        return 0;
 682}
 683
 684static void s3c2410wdt_shutdown(struct platform_device *dev)
 685{
 686        struct s3c2410_wdt *wdt = platform_get_drvdata(dev);
 687
 688        s3c2410wdt_mask_and_disable_reset(wdt, true);
 689
 690        s3c2410wdt_stop(&wdt->wdt_device);
 691}
 692
 693#ifdef CONFIG_PM_SLEEP
 694
 695static int s3c2410wdt_suspend(struct device *dev)
 696{
 697        int ret;
 698        struct s3c2410_wdt *wdt = dev_get_drvdata(dev);
 699
 700        /* Save watchdog state, and turn it off. */
 701        wdt->wtcon_save = readl(wdt->reg_base + S3C2410_WTCON);
 702        wdt->wtdat_save = readl(wdt->reg_base + S3C2410_WTDAT);
 703
 704        ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
 705        if (ret < 0)
 706                return ret;
 707
 708        /* Note that WTCNT doesn't need to be saved. */
 709        s3c2410wdt_stop(&wdt->wdt_device);
 710
 711        return 0;
 712}
 713
 714static int s3c2410wdt_resume(struct device *dev)
 715{
 716        int ret;
 717        struct s3c2410_wdt *wdt = dev_get_drvdata(dev);
 718
 719        /* Restore watchdog state. */
 720        writel(wdt->wtdat_save, wdt->reg_base + S3C2410_WTDAT);
 721        writel(wdt->wtdat_save, wdt->reg_base + S3C2410_WTCNT);/* Reset count */
 722        writel(wdt->wtcon_save, wdt->reg_base + S3C2410_WTCON);
 723
 724        ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
 725        if (ret < 0)
 726                return ret;
 727
 728        dev_info(dev, "watchdog %sabled\n",
 729                (wdt->wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
 730
 731        return 0;
 732}
 733#endif
 734
 735static SIMPLE_DEV_PM_OPS(s3c2410wdt_pm_ops, s3c2410wdt_suspend,
 736                        s3c2410wdt_resume);
 737
 738static struct platform_driver s3c2410wdt_driver = {
 739        .probe          = s3c2410wdt_probe,
 740        .remove         = s3c2410wdt_remove,
 741        .shutdown       = s3c2410wdt_shutdown,
 742        .id_table       = s3c2410_wdt_ids,
 743        .driver         = {
 744                .name   = "s3c2410-wdt",
 745                .pm     = &s3c2410wdt_pm_ops,
 746                .of_match_table = of_match_ptr(s3c2410_wdt_match),
 747        },
 748};
 749
 750module_platform_driver(s3c2410wdt_driver);
 751
 752MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, Dimitry Andric <dimitry.andric@tomtom.com>");
 753MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
 754MODULE_LICENSE("GPL");
 755