drivers/watchdog/s3c2410_wdt.c

   1 /* linux/drivers/char/watchdog/s3c2410_wdt.c
   2  *
   3  * Copyright (c) 2004 Simtec Electronics
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *
   6  * S3C2410 Watchdog Timer Support
   7  *
   8  * Based on, softdog.c by Alan Cox,
   9  *     (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  24 */
  25
  26 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  27
  28 #include <linux/module.h>
  29 #include <linux/moduleparam.h>
  30 #include <linux/types.h>
  31 #include <linux/timer.h>
  32 #include <linux/watchdog.h>
  33 #include <linux/platform_device.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/clk.h>
  36 #include <linux/uaccess.h>
  37 #include <linux/io.h>
  38 #include <linux/cpufreq.h>
  39 #include <linux/slab.h>
  40 #include <linux/err.h>
  41 #include <linux/of.h>
  42 #include <linux/mfd/syscon.h>
  43 #include <linux/regmap.h>
  44 #include <linux/reboot.h>
  45 #include <linux/delay.h>
  46
  47 #define S3C2410_WTCON           0x00
  48 #define S3C2410_WTDAT           0x04
  49 #define S3C2410_WTCNT           0x08
  50
  51 #define S3C2410_WTCON_RSTEN     (1 << 0)
  52 #define S3C2410_WTCON_INTEN     (1 << 2)
  53 #define S3C2410_WTCON_ENABLE    (1 << 5)
  54
  55 #define S3C2410_WTCON_DIV16     (0 << 3)
  56 #define S3C2410_WTCON_DIV32     (1 << 3)
  57 #define S3C2410_WTCON_DIV64     (2 << 3)
  58 #define S3C2410_WTCON_DIV128    (3 << 3)
  59
  60 #define S3C2410_WTCON_PRESCALE(x)       ((x) << 8)
  61 #define S3C2410_WTCON_PRESCALE_MASK     (0xff << 8)
  62
  63 #define CONFIG_S3C2410_WATCHDOG_ATBOOT          (0)
  64 #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME    (15)
  65
  66 #define EXYNOS5_RST_STAT_REG_OFFSET             0x0404
  67 #define EXYNOS5_WDT_DISABLE_REG_OFFSET          0x0408
  68 #define EXYNOS5_WDT_MASK_RESET_REG_OFFSET       0x040c
  69 #define QUIRK_HAS_PMU_CONFIG                    (1 << 0)
  70 #define QUIRK_HAS_RST_STAT                      (1 << 1)
  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
  76 static bool nowayout    = WATCHDOG_NOWAYOUT;
  77 static int tmr_margin;
  78 static int tmr_atboot   = CONFIG_S3C2410_WATCHDOG_ATBOOT;
  79 static int soft_noboot;
  80 static int debug;
  81
  82 module_param(tmr_margin,  int, 0);
  83 module_param(tmr_atboot,  int, 0);
  84 module_param(nowayout,   bool, 0);
  85 module_param(soft_noboot, int, 0);
  86 module_param(debug,       int, 0);
  87
  88 MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. (default="
  89                 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
  90 MODULE_PARM_DESC(tmr_atboot,
  91                 "Watchdog is started at boot time if set to 1, default="
  92                         __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
  93 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  94                         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  95 MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, "
  96                         "0 to reboot (default 0)");
  97 MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug (default 0)");
  98
  99 /**
 100  * struct s3c2410_wdt_variant - Per-variant config data
 101  *
 102  * @disable_reg: Offset in pmureg for the register that disables the watchdog
 103  * timer reset functionality.
 104  * @mask_reset_reg: Offset in pmureg for the register that masks the watchdog
 105  * timer reset functionality.
 106  * @mask_bit: Bit number for the watchdog timer in the disable register and the
 107  * mask reset register.
 108  * @rst_stat_reg: Offset in pmureg for the register that has the reset status.
 109  * @rst_stat_bit: Bit number in the rst_stat register indicating a watchdog
 110  * reset.
 111  * @quirks: A bitfield of quirks.
 112  */
 113
 114 struct s3c2410_wdt_variant {
 115         int disable_reg;
 116         int mask_reset_reg;
 117         int mask_bit;
 118         int rst_stat_reg;
 119         int rst_stat_bit;
 120         u32 quirks;
 121 };
 122
 123 struct s3c2410_wdt {
 124         struct device           *dev;
 125         struct clk              *clock;
 126         void __iomem            *reg_base;
 127         unsigned int            count;
 128         spinlock_t              lock;
 129         unsigned long           wtcon_save;
 130         unsigned long           wtdat_save;
 131         struct watchdog_device  wdt_device;
 132         struct notifier_block   freq_transition;
 133         struct notifier_block   restart_handler;
 134         struct s3c2410_wdt_variant *drv_data;
 135         struct regmap *pmureg;
 136 };
 137
 138 static const struct s3c2410_wdt_variant drv_data_s3c2410 = {
 139         .quirks = 0
 140 };
 141
 142 #ifdef CONFIG_OF
 143 static const struct s3c2410_wdt_variant drv_data_exynos5250  = {
 144         .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET,
 145         .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET,
 146         .mask_bit = 20,
 147         .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
 148         .rst_stat_bit = 20,
 149         .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT,
 150 };
 151
 152 static 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 };
 160
 161 static const struct s3c2410_wdt_variant drv_data_exynos7 = {
 162         .disable_reg = EXYNOS5_WDT_DISABLE_REG_OFFSET,
 163         .mask_reset_reg = EXYNOS5_WDT_MASK_RESET_REG_OFFSET,
 164         .mask_bit = 23,
 165         .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
 166         .rst_stat_bit = 23,     /* A57 WDTRESET */
 167         .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT,
 168 };
 169
 170 static const struct of_device_id s3c2410_wdt_match[] = {
 171         { .compatible = "samsung,s3c2410-wdt",
 172           .data = &drv_data_s3c2410 },
 173         { .compatible = "samsung,exynos5250-wdt",
 174           .data = &drv_data_exynos5250 },
 175         { .compatible = "samsung,exynos5420-wdt",
 176           .data = &drv_data_exynos5420 },
 177         { .compatible = "samsung,exynos7-wdt",
 178           .data = &drv_data_exynos7 },
 179         {},
 180 };
 181 MODULE_DEVICE_TABLE(of, s3c2410_wdt_match);
 182 #endif
 183
 184 static const struct platform_device_id s3c2410_wdt_ids[] = {
 185         {
 186                 .name = "s3c2410-wdt",
 187                 .driver_data = (unsigned long)&drv_data_s3c2410,
 188         },
 189         {}
 190 };
 191 MODULE_DEVICE_TABLE(platform, s3c2410_wdt_ids);
 192
 193 /* watchdog control routines */
 194
 195 #define DBG(fmt, ...)                                   \
 196 do {                                                    \
 197         if (debug)                                      \
 198                 pr_info(fmt, ##__VA_ARGS__);            \
 199 } while (0)
 200
 201 /* functions */
 202
 203 static inline struct s3c2410_wdt *freq_to_wdt(struct notifier_block *nb)
 204 {
 205         return container_of(nb, struct s3c2410_wdt, freq_transition);
 206 }
 207
 208 static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask)
 209 {
 210         int ret;
 211         u32 mask_val = 1 << wdt->drv_data->mask_bit;
 212         u32 val = 0;
 213
 214         /* No need to do anything if no PMU CONFIG needed */
 215         if (!(wdt->drv_data->quirks & QUIRK_HAS_PMU_CONFIG))
 216                 return 0;
 217
 218         if (mask)
 219                 val = mask_val;
 220
 221         ret = regmap_update_bits(wdt->pmureg,
 222                         wdt->drv_data->disable_reg,
 223                         mask_val, val);
 224         if (ret < 0)
 225                 goto error;
 226
 227         ret = regmap_update_bits(wdt->pmureg,
 228                         wdt->drv_data->mask_reset_reg,
 229                         mask_val, val);
 230  error:
 231         if (ret < 0)
 232                 dev_err(wdt->dev, "failed to update reg(%d)\n", ret);
 233
 234         return ret;
 235 }
 236
 237 static int s3c2410wdt_keepalive(struct watchdog_device *wdd)
 238 {
 239         struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 240
 241         spin_lock(&wdt->lock);
 242         writel(wdt->count, wdt->reg_base + S3C2410_WTCNT);
 243         spin_unlock(&wdt->lock);
 244
 245         return 0;
 246 }
 247
 248 static void __s3c2410wdt_stop(struct s3c2410_wdt *wdt)
 249 {
 250         unsigned long wtcon;
 251
 252         wtcon = readl(wdt->reg_base + S3C2410_WTCON);
 253         wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
 254         writel(wtcon, wdt->reg_base + S3C2410_WTCON);
 255 }
 256
 257 static int s3c2410wdt_stop(struct watchdog_device *wdd)
 258 {
 259         struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 260
 261         spin_lock(&wdt->lock);
 262         __s3c2410wdt_stop(wdt);
 263         spin_unlock(&wdt->lock);
 264
 265         return 0;
 266 }
 267
 268 static int s3c2410wdt_start(struct watchdog_device *wdd)
 269 {
 270         unsigned long wtcon;
 271         struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 272
 273         spin_lock(&wdt->lock);
 274
 275         __s3c2410wdt_stop(wdt);
 276
 277         wtcon = readl(wdt->reg_base + S3C2410_WTCON);
 278         wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
 279
 280         if (soft_noboot) {
 281                 wtcon |= S3C2410_WTCON_INTEN;
 282                 wtcon &= ~S3C2410_WTCON_RSTEN;
 283         } else {
 284                 wtcon &= ~S3C2410_WTCON_INTEN;
 285                 wtcon |= S3C2410_WTCON_RSTEN;
 286         }
 287
 288         DBG("%s: count=0x%08x, wtcon=%08lx\n",
 289             __func__, wdt->count, wtcon);
 290
 291         writel(wdt->count, wdt->reg_base + S3C2410_WTDAT);
 292         writel(wdt->count, wdt->reg_base + S3C2410_WTCNT);
 293         writel(wtcon, wdt->reg_base + S3C2410_WTCON);
 294         spin_unlock(&wdt->lock);
 295
 296         return 0;
 297 }
 298
 299 static inline int s3c2410wdt_is_running(struct s3c2410_wdt *wdt)
 300 {
 301         return readl(wdt->reg_base + S3C2410_WTCON) & S3C2410_WTCON_ENABLE;
 302 }
 303
 304 static int s3c2410wdt_set_heartbeat(struct watchdog_device *wdd, unsigned timeout)
 305 {
 306         struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 307         unsigned long freq = clk_get_rate(wdt->clock);
 308         unsigned int count;
 309         unsigned int divisor = 1;
 310         unsigned long wtcon;
 311
 312         if (timeout < 1)
 313                 return -EINVAL;
 314
 315         freq = DIV_ROUND_UP(freq, 128);
 316         count = timeout * freq;
 317
 318         DBG("%s: count=%d, timeout=%d, freq=%lu\n",
 319             __func__, count, timeout, freq);
 320
 321         /* if the count is bigger than the watchdog register,
 322            then work out what we need to do (and if) we can
 323            actually make this value
 324         */
 325
 326         if (count >= 0x10000) {
 327                 divisor = DIV_ROUND_UP(count, 0xffff);
 328
 329                 if (divisor > 0x100) {
 330                         dev_err(wdt->dev, "timeout %d too big\n", timeout);
 331                         return -EINVAL;
 332                 }
 333         }
 334
 335         DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
 336             __func__, timeout, divisor, count, DIV_ROUND_UP(count, divisor));
 337
 338         count = DIV_ROUND_UP(count, divisor);
 339         wdt->count = count;
 340
 341         /* update the pre-scaler */
 342         wtcon = readl(wdt->reg_base + S3C2410_WTCON);
 343         wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
 344         wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
 345
 346         writel(count, wdt->reg_base + S3C2410_WTDAT);
 347         writel(wtcon, wdt->reg_base + S3C2410_WTCON);
 348
 349         wdd->timeout = (count * divisor) / freq;
 350
 351         return 0;
 352 }
 353
 354 #define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
 355
 356 static const struct watchdog_info s3c2410_wdt_ident = {
 357         .options          =     OPTIONS,
 358         .firmware_version =     0,
 359         .identity         =     "S3C2410 Watchdog",
 360 };
 361
 362 static struct watchdog_ops s3c2410wdt_ops = {
 363         .owner = THIS_MODULE,
 364         .start = s3c2410wdt_start,
 365         .stop = s3c2410wdt_stop,
 366         .ping = s3c2410wdt_keepalive,
 367         .set_timeout = s3c2410wdt_set_heartbeat,
 368 };
 369
 370 static struct watchdog_device s3c2410_wdd = {
 371         .info = &s3c2410_wdt_ident,
 372         .ops = &s3c2410wdt_ops,
 373         .timeout = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME,
 374 };
 375
 376 /* interrupt handler code */
 377
 378 static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
 379 {
 380         struct s3c2410_wdt *wdt = platform_get_drvdata(param);
 381
 382         dev_info(wdt->dev, "watchdog timer expired (irq)\n");
 383
 384         s3c2410wdt_keepalive(&wdt->wdt_device);
 385         return IRQ_HANDLED;
 386 }
 387
 388 #ifdef CONFIG_ARM_S3C24XX_CPUFREQ
 389
 390 static int s3c2410wdt_cpufreq_transition(struct notifier_block *nb,
 391                                           unsigned long val, void *data)
 392 {
 393         int ret;
 394         struct s3c2410_wdt *wdt = freq_to_wdt(nb);
 395
 396         if (!s3c2410wdt_is_running(wdt))
 397                 goto done;
 398
 399         if (val == CPUFREQ_PRECHANGE) {
 400                 /* To ensure that over the change we don't cause the
 401                  * watchdog to trigger, we perform an keep-alive if
 402                  * the watchdog is running.
 403                  */
 404
 405                 s3c2410wdt_keepalive(&wdt->wdt_device);
 406         } else if (val == CPUFREQ_POSTCHANGE) {
 407                 s3c2410wdt_stop(&wdt->wdt_device);
 408
 409                 ret = s3c2410wdt_set_heartbeat(&wdt->wdt_device,
 410                                                 wdt->wdt_device.timeout);
 411
 412                 if (ret >= 0)
 413                         s3c2410wdt_start(&wdt->wdt_device);
 414                 else
 415                         goto err;
 416         }
 417
 418 done:
 419         return 0;
 420
 421  err:
 422         dev_err(wdt->dev, "cannot set new value for timeout %d\n",
 423                                 wdt->wdt_device.timeout);
 424         return ret;
 425 }
 426
 427 static inline int s3c2410wdt_cpufreq_register(struct s3c2410_wdt *wdt)
 428 {
 429         wdt->freq_transition.notifier_call = s3c2410wdt_cpufreq_transition;
 430
 431         return cpufreq_register_notifier(&wdt->freq_transition,
 432                                          CPUFREQ_TRANSITION_NOTIFIER);
 433 }
 434
 435 static inline void s3c2410wdt_cpufreq_deregister(struct s3c2410_wdt *wdt)
 436 {
 437         wdt->freq_transition.notifier_call = s3c2410wdt_cpufreq_transition;
 438
 439         cpufreq_unregister_notifier(&wdt->freq_transition,
 440                                     CPUFREQ_TRANSITION_NOTIFIER);
 441 }
 442
 443 #else
 444
 445 static inline int s3c2410wdt_cpufreq_register(struct s3c2410_wdt *wdt)
 446 {
 447         return 0;
 448 }
 449
 450 static inline void s3c2410wdt_cpufreq_deregister(struct s3c2410_wdt *wdt)
 451 {
 452 }
 453 #endif
 454
 455 static int s3c2410wdt_restart(struct notifier_block *this,
 456                               unsigned long mode, void *cmd)
 457 {
 458         struct s3c2410_wdt *wdt = container_of(this, struct s3c2410_wdt,
 459                                                restart_handler);
 460         void __iomem *wdt_base = wdt->reg_base;
 461
 462         /* disable watchdog, to be safe  */
 463         writel(0, wdt_base + S3C2410_WTCON);
 464
 465         /* put initial values into count and data */
 466         writel(0x80, wdt_base + S3C2410_WTCNT);
 467         writel(0x80, wdt_base + S3C2410_WTDAT);
 468
 469         /* set the watchdog to go and reset... */
 470         writel(S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV16 |
 471                 S3C2410_WTCON_RSTEN | S3C2410_WTCON_PRESCALE(0x20),
 472                 wdt_base + S3C2410_WTCON);
 473
 474         /* wait for reset to assert... */
 475         mdelay(500);
 476
 477         return NOTIFY_DONE;
 478 }
 479
 480 static inline unsigned int s3c2410wdt_get_bootstatus(struct s3c2410_wdt *wdt)
 481 {
 482         unsigned int rst_stat;
 483         int ret;
 484
 485         if (!(wdt->drv_data->quirks & QUIRK_HAS_RST_STAT))
 486                 return 0;
 487
 488         ret = regmap_read(wdt->pmureg, wdt->drv_data->rst_stat_reg, &rst_stat);
 489         if (ret)
 490                 dev_warn(wdt->dev, "Couldn't get RST_STAT register\n");
 491         else if (rst_stat & BIT(wdt->drv_data->rst_stat_bit))
 492                 return WDIOF_CARDRESET;
 493
 494         return 0;
 495 }
 496
 497 /* s3c2410_get_wdt_driver_data */
 498 static inline struct s3c2410_wdt_variant *
 499 get_wdt_drv_data(struct platform_device *pdev)
 500 {
 501         if (pdev->dev.of_node) {
 502                 const struct of_device_id *match;
 503                 match = of_match_node(s3c2410_wdt_match, pdev->dev.of_node);
 504                 return (struct s3c2410_wdt_variant *)match->data;
 505         } else {
 506                 return (struct s3c2410_wdt_variant *)
 507                         platform_get_device_id(pdev)->driver_data;
 508         }
 509 }
 510
 511 static int s3c2410wdt_probe(struct platform_device *pdev)
 512 {
 513         struct device *dev;
 514         struct s3c2410_wdt *wdt;
 515         struct resource *wdt_mem;
 516         struct resource *wdt_irq;
 517         unsigned int wtcon;
 518         int started = 0;
 519         int ret;
 520
 521         DBG("%s: probe=%p\n", __func__, pdev);
 522
 523         dev = &pdev->dev;
 524
 525         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 526         if (!wdt)
 527                 return -ENOMEM;
 528
 529         wdt->dev = &pdev->dev;
 530         spin_lock_init(&wdt->lock);
 531         wdt->wdt_device = s3c2410_wdd;
 532
 533         wdt->drv_data = get_wdt_drv_data(pdev);
 534         if (wdt->drv_data->quirks & QUIRKS_HAVE_PMUREG) {
 535                 wdt->pmureg = syscon_regmap_lookup_by_phandle(dev->of_node,
 536                                                 "samsung,syscon-phandle");
 537                 if (IS_ERR(wdt->pmureg)) {
 538                         dev_err(dev, "syscon regmap lookup failed.\n");
 539                         return PTR_ERR(wdt->pmureg);
 540                 }
 541         }
 542
 543         wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 544         if (wdt_irq == NULL) {
 545                 dev_err(dev, "no irq resource specified\n");
 546                 ret = -ENOENT;
 547                 goto err;
 548         }
 549
 550         /* get the memory region for the watchdog timer */
 551         wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 552         wdt->reg_base = devm_ioremap_resource(dev, wdt_mem);
 553         if (IS_ERR(wdt->reg_base)) {
 554                 ret = PTR_ERR(wdt->reg_base);
 555                 goto err;
 556         }
 557
 558         DBG("probe: mapped reg_base=%p\n", wdt->reg_base);
 559
 560         wdt->clock = devm_clk_get(dev, "watchdog");
 561         if (IS_ERR(wdt->clock)) {
 562                 dev_err(dev, "failed to find watchdog clock source\n");
 563                 ret = PTR_ERR(wdt->clock);
 564                 goto err;
 565         }
 566
 567         ret = clk_prepare_enable(wdt->clock);
 568         if (ret < 0) {
 569                 dev_err(dev, "failed to enable clock\n");
 570                 return ret;
 571         }
 572
 573         ret = s3c2410wdt_cpufreq_register(wdt);
 574         if (ret < 0) {
 575                 dev_err(dev, "failed to register cpufreq\n");
 576                 goto err_clk;
 577         }
 578
 579         watchdog_set_drvdata(&wdt->wdt_device, wdt);
 580
 581         /* see if we can actually set the requested timer margin, and if
 582          * not, try the default value */
 583
 584         watchdog_init_timeout(&wdt->wdt_device, tmr_margin, &pdev->dev);
 585         ret = s3c2410wdt_set_heartbeat(&wdt->wdt_device,
 586                                         wdt->wdt_device.timeout);
 587         if (ret) {
 588                 started = s3c2410wdt_set_heartbeat(&wdt->wdt_device,
 589                                         CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
 590
 591                 if (started == 0)
 592                         dev_info(dev,
 593                            "tmr_margin value out of range, default %d used\n",
 594                                CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
 595                 else
 596                         dev_info(dev, "default timer value is out of range, "
 597                                                         "cannot start\n");
 598         }
 599
 600         ret = devm_request_irq(dev, wdt_irq->start, s3c2410wdt_irq, 0,
 601                                 pdev->name, pdev);
 602         if (ret != 0) {
 603                 dev_err(dev, "failed to install irq (%d)\n", ret);
 604                 goto err_cpufreq;
 605         }
 606
 607         watchdog_set_nowayout(&wdt->wdt_device, nowayout);
 608
 609         wdt->wdt_device.bootstatus = s3c2410wdt_get_bootstatus(wdt);
 610
 611         ret = watchdog_register_device(&wdt->wdt_device);
 612         if (ret) {
 613                 dev_err(dev, "cannot register watchdog (%d)\n", ret);
 614                 goto err_cpufreq;
 615         }
 616
 617         ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
 618         if (ret < 0)
 619                 goto err_unregister;
 620
 621         if (tmr_atboot && started == 0) {
 622                 dev_info(dev, "starting watchdog timer\n");
 623                 s3c2410wdt_start(&wdt->wdt_device);
 624         } else if (!tmr_atboot) {
 625                 /* if we're not enabling the watchdog, then ensure it is
 626                  * disabled if it has been left running from the bootloader
 627                  * or other source */
 628
 629                 s3c2410wdt_stop(&wdt->wdt_device);
 630         }
 631
 632         platform_set_drvdata(pdev, wdt);
 633
 634         wdt->restart_handler.notifier_call = s3c2410wdt_restart;
 635         wdt->restart_handler.priority = 128;
 636         ret = register_restart_handler(&wdt->restart_handler);
 637         if (ret)
 638                 pr_err("cannot register restart handler, %d\n", ret);
 639
 640         /* print out a statement of readiness */
 641
 642         wtcon = readl(wdt->reg_base + S3C2410_WTCON);
 643
 644         dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n",
 645                  (wtcon & S3C2410_WTCON_ENABLE) ?  "" : "in",
 646                  (wtcon & S3C2410_WTCON_RSTEN) ? "en" : "dis",
 647                  (wtcon & S3C2410_WTCON_INTEN) ? "en" : "dis");
 648
 649         return 0;
 650
 651  err_unregister:
 652         watchdog_unregister_device(&wdt->wdt_device);
 653
 654  err_cpufreq:
 655         s3c2410wdt_cpufreq_deregister(wdt);
 656
 657  err_clk:
 658         clk_disable_unprepare(wdt->clock);
 659
 660  err:
 661         return ret;
 662 }
 663
 664 static int s3c2410wdt_remove(struct platform_device *dev)
 665 {
 666         int ret;
 667         struct s3c2410_wdt *wdt = platform_get_drvdata(dev);
 668
 669         unregister_restart_handler(&wdt->restart_handler);
 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
 684 static 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
 695 static 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
 714 static 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
 735 static SIMPLE_DEV_PM_OPS(s3c2410wdt_pm_ops, s3c2410wdt_suspend,
 736                         s3c2410wdt_resume);
 737
 738 static 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
 750 module_platform_driver(s3c2410wdt_driver);
 751
 752 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
 753               "Dimitry Andric <dimitry.andric@tomtom.com>");
 754 MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
 755 MODULE_LICENSE("GPL");