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