drivers/watchdog/omap_wdt.c

   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/mm.h>
  35 #include <linux/watchdog.h>
  36 #include <linux/reboot.h>
  37 #include <linux/err.h>
  38 #include <linux/platform_device.h>
  39 #include <linux/moduleparam.h>
  40 #include <linux/io.h>
  41 #include <linux/slab.h>
  42 #include <linux/pm_runtime.h>
  43 #include <linux/platform_data/omap-wd-timer.h>
  44
  45 #include "omap_wdt.h"
  46
  47 static bool nowayout = WATCHDOG_NOWAYOUT;
  48 module_param(nowayout, bool, 0);
  49 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  50         "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  51
  52 static unsigned timer_margin;
  53 module_param(timer_margin, uint, 0);
  54 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
  55
  56 #define to_omap_wdt_dev(_wdog)  container_of(_wdog, struct omap_wdt_dev, wdog)
  57
  58 static bool early_enable;
  59 module_param(early_enable, bool, 0);
  60 MODULE_PARM_DESC(early_enable,
  61         "Watchdog is started on module insertion (default=0)");
  62
  63 struct omap_wdt_dev {
  64         struct watchdog_device wdog;
  65         void __iomem    *base;          /* physical */
  66         struct device   *dev;
  67         bool            omap_wdt_users;
  68         int             wdt_trgr_pattern;
  69         struct mutex    lock;           /* to avoid races with PM */
  70 };
  71
  72 static void omap_wdt_reload(struct omap_wdt_dev *wdev)
  73 {
  74         void __iomem    *base = wdev->base;
  75
  76         /* wait for posted write to complete */
  77         while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08)
  78                 cpu_relax();
  79
  80         wdev->wdt_trgr_pattern = ~wdev->wdt_trgr_pattern;
  81         writel_relaxed(wdev->wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
  82
  83         /* wait for posted write to complete */
  84         while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08)
  85                 cpu_relax();
  86         /* reloaded WCRR from WLDR */
  87 }
  88
  89 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
  90 {
  91         void __iomem *base = wdev->base;
  92
  93         /* Sequence to enable the watchdog */
  94         writel_relaxed(0xBBBB, base + OMAP_WATCHDOG_SPR);
  95         while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10)
  96                 cpu_relax();
  97
  98         writel_relaxed(0x4444, base + OMAP_WATCHDOG_SPR);
  99         while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10)
 100                 cpu_relax();
 101 }
 102
 103 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
 104 {
 105         void __iomem *base = wdev->base;
 106
 107         /* sequence required to disable watchdog */
 108         writel_relaxed(0xAAAA, base + OMAP_WATCHDOG_SPR);       /* TIMER_MODE */
 109         while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10)
 110                 cpu_relax();
 111
 112         writel_relaxed(0x5555, base + OMAP_WATCHDOG_SPR);       /* TIMER_MODE */
 113         while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10)
 114                 cpu_relax();
 115 }
 116
 117 static void omap_wdt_set_timer(struct omap_wdt_dev *wdev,
 118                                    unsigned int timeout)
 119 {
 120         u32 pre_margin = GET_WLDR_VAL(timeout);
 121         void __iomem *base = wdev->base;
 122
 123         /* just count up at 32 KHz */
 124         while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04)
 125                 cpu_relax();
 126
 127         writel_relaxed(pre_margin, base + OMAP_WATCHDOG_LDR);
 128         while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04)
 129                 cpu_relax();
 130 }
 131
 132 static int omap_wdt_start(struct watchdog_device *wdog)
 133 {
 134         struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
 135         void __iomem *base = wdev->base;
 136
 137         mutex_lock(&wdev->lock);
 138
 139         wdev->omap_wdt_users = true;
 140
 141         pm_runtime_get_sync(wdev->dev);
 142
 143         /*
 144          * Make sure the watchdog is disabled. This is unfortunately required
 145          * because writing to various registers with the watchdog running has no
 146          * effect.
 147          */
 148         omap_wdt_disable(wdev);
 149
 150         /* initialize prescaler */
 151         while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01)
 152                 cpu_relax();
 153
 154         writel_relaxed((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
 155         while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01)
 156                 cpu_relax();
 157
 158         omap_wdt_set_timer(wdev, wdog->timeout);
 159         omap_wdt_reload(wdev); /* trigger loading of new timeout value */
 160         omap_wdt_enable(wdev);
 161
 162         mutex_unlock(&wdev->lock);
 163
 164         return 0;
 165 }
 166
 167 static int omap_wdt_stop(struct watchdog_device *wdog)
 168 {
 169         struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
 170
 171         mutex_lock(&wdev->lock);
 172         omap_wdt_disable(wdev);
 173         pm_runtime_put_sync(wdev->dev);
 174         wdev->omap_wdt_users = false;
 175         mutex_unlock(&wdev->lock);
 176         return 0;
 177 }
 178
 179 static int omap_wdt_ping(struct watchdog_device *wdog)
 180 {
 181         struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
 182
 183         mutex_lock(&wdev->lock);
 184         omap_wdt_reload(wdev);
 185         mutex_unlock(&wdev->lock);
 186
 187         return 0;
 188 }
 189
 190 static int omap_wdt_set_timeout(struct watchdog_device *wdog,
 191                                 unsigned int timeout)
 192 {
 193         struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog);
 194
 195         mutex_lock(&wdev->lock);
 196         omap_wdt_disable(wdev);
 197         omap_wdt_set_timer(wdev, timeout);
 198         omap_wdt_enable(wdev);
 199         omap_wdt_reload(wdev);
 200         wdog->timeout = timeout;
 201         mutex_unlock(&wdev->lock);
 202
 203         return 0;
 204 }
 205
 206 static unsigned int omap_wdt_get_timeleft(struct watchdog_device *wdog)
 207 {
 208         struct omap_wdt_dev *wdev = watchdog_get_drvdata(wdog);
 209         void __iomem *base = wdev->base;
 210         u32 value;
 211
 212         value = readl_relaxed(base + OMAP_WATCHDOG_CRR);
 213         return GET_WCCR_SECS(value);
 214 }
 215
 216 static const struct watchdog_info omap_wdt_info = {
 217         .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 218         .identity = "OMAP Watchdog",
 219 };
 220
 221 static const struct watchdog_ops omap_wdt_ops = {
 222         .owner          = THIS_MODULE,
 223         .start          = omap_wdt_start,
 224         .stop           = omap_wdt_stop,
 225         .ping           = omap_wdt_ping,
 226         .set_timeout    = omap_wdt_set_timeout,
 227         .get_timeleft   = omap_wdt_get_timeleft,
 228 };
 229
 230 static int omap_wdt_probe(struct platform_device *pdev)
 231 {
 232         struct omap_wd_timer_platform_data *pdata = dev_get_platdata(&pdev->dev);
 233         struct resource *res;
 234         struct omap_wdt_dev *wdev;
 235         int ret;
 236
 237         wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
 238         if (!wdev)
 239                 return -ENOMEM;
 240
 241         wdev->omap_wdt_users    = false;
 242         wdev->dev               = &pdev->dev;
 243         wdev->wdt_trgr_pattern  = 0x1234;
 244         mutex_init(&wdev->lock);
 245
 246         /* reserve static register mappings */
 247         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 248         wdev->base = devm_ioremap_resource(&pdev->dev, res);
 249         if (IS_ERR(wdev->base))
 250                 return PTR_ERR(wdev->base);
 251
 252         wdev->wdog.info = &omap_wdt_info;
 253         wdev->wdog.ops = &omap_wdt_ops;
 254         wdev->wdog.min_timeout = TIMER_MARGIN_MIN;
 255         wdev->wdog.max_timeout = TIMER_MARGIN_MAX;
 256         wdev->wdog.parent = &pdev->dev;
 257
 258         if (watchdog_init_timeout(&wdev->wdog, timer_margin, &pdev->dev) < 0)
 259                 wdev->wdog.timeout = TIMER_MARGIN_DEFAULT;
 260
 261         watchdog_set_nowayout(&wdev->wdog, nowayout);
 262
 263         platform_set_drvdata(pdev, wdev);
 264
 265         pm_runtime_enable(wdev->dev);
 266         pm_runtime_get_sync(wdev->dev);
 267
 268         if (pdata && pdata->read_reset_sources) {
 269                 u32 rs = pdata->read_reset_sources();
 270                 if (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT))
 271                         wdev->wdog.bootstatus = WDIOF_CARDRESET;
 272         }
 273
 274         omap_wdt_disable(wdev);
 275
 276         ret = watchdog_register_device(&wdev->wdog);
 277         if (ret) {
 278                 pm_runtime_disable(wdev->dev);
 279                 return ret;
 280         }
 281
 282         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
 283                 readl_relaxed(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 284                 wdev->wdog.timeout);
 285
 286         pm_runtime_put_sync(wdev->dev);
 287
 288         if (early_enable)
 289                 omap_wdt_start(&wdev->wdog);
 290
 291         return 0;
 292 }
 293
 294 static void omap_wdt_shutdown(struct platform_device *pdev)
 295 {
 296         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 297
 298         mutex_lock(&wdev->lock);
 299         if (wdev->omap_wdt_users) {
 300                 omap_wdt_disable(wdev);
 301                 pm_runtime_put_sync(wdev->dev);
 302         }
 303         mutex_unlock(&wdev->lock);
 304 }
 305
 306 static int omap_wdt_remove(struct platform_device *pdev)
 307 {
 308         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 309
 310         pm_runtime_disable(wdev->dev);
 311         watchdog_unregister_device(&wdev->wdog);
 312
 313         return 0;
 314 }
 315
 316 #ifdef  CONFIG_PM
 317
 318 /* REVISIT ... not clear this is the best way to handle system suspend; and
 319  * it's very inappropriate for selective device suspend (e.g. suspending this
 320  * through sysfs rather than by stopping the watchdog daemon).  Also, this
 321  * may not play well enough with NOWAYOUT...
 322  */
 323
 324 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 325 {
 326         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 327
 328         mutex_lock(&wdev->lock);
 329         if (wdev->omap_wdt_users) {
 330                 omap_wdt_disable(wdev);
 331                 pm_runtime_put_sync(wdev->dev);
 332         }
 333         mutex_unlock(&wdev->lock);
 334
 335         return 0;
 336 }
 337
 338 static int omap_wdt_resume(struct platform_device *pdev)
 339 {
 340         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
 341
 342         mutex_lock(&wdev->lock);
 343         if (wdev->omap_wdt_users) {
 344                 pm_runtime_get_sync(wdev->dev);
 345                 omap_wdt_enable(wdev);
 346                 omap_wdt_reload(wdev);
 347         }
 348         mutex_unlock(&wdev->lock);
 349
 350         return 0;
 351 }
 352
 353 #else
 354 #define omap_wdt_suspend        NULL
 355 #define omap_wdt_resume         NULL
 356 #endif
 357
 358 static const struct of_device_id omap_wdt_of_match[] = {
 359         { .compatible = "ti,omap3-wdt", },
 360         {},
 361 };
 362 MODULE_DEVICE_TABLE(of, omap_wdt_of_match);
 363
 364 static struct platform_driver omap_wdt_driver = {
 365         .probe          = omap_wdt_probe,
 366         .remove         = omap_wdt_remove,
 367         .shutdown       = omap_wdt_shutdown,
 368         .suspend        = omap_wdt_suspend,
 369         .resume         = omap_wdt_resume,
 370         .driver         = {
 371                 .name   = "omap_wdt",
 372                 .of_match_table = omap_wdt_of_match,
 373         },
 374 };
 375
 376 module_platform_driver(omap_wdt_driver);
 377
 378 MODULE_AUTHOR("George G. Davis");
 379 MODULE_LICENSE("GPL");
 380 MODULE_ALIAS("platform:omap_wdt");