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