drivers/watchdog/bcm47xx_wdt.c

   1 /*
   2  *  Watchdog driver for Broadcom BCM47XX
   3  *
   4  *  Copyright (C) 2008 Aleksandar Radovanovic <biblbroks@sezampro.rs>
   5  *  Copyright (C) 2009 Matthieu CASTET <castet.matthieu@free.fr>
   6  *  Copyright (C) 2012-2013 Hauke Mehrtens <hauke@hauke-m.de>
   7  *
   8  *  This program is free software; you can redistribute it and/or
   9  *  modify it under the terms of the GNU General Public License
  10  *  as published by the Free Software Foundation; either version
  11  *  2 of the License, or (at your option) any later version.
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/bcm47xx_wdt.h>
  17 #include <linux/bitops.h>
  18 #include <linux/errno.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/reboot.h>
  24 #include <linux/types.h>
  25 #include <linux/watchdog.h>
  26 #include <linux/timer.h>
  27 #include <linux/jiffies.h>
  28
  29 #define DRV_NAME                "bcm47xx_wdt"
  30
  31 #define WDT_DEFAULT_TIME        30      /* seconds */
  32 #define WDT_SOFTTIMER_MAX       255     /* seconds */
  33 #define WDT_SOFTTIMER_THRESHOLD 60      /* seconds */
  34
  35 static int timeout = WDT_DEFAULT_TIME;
  36 static bool nowayout = WATCHDOG_NOWAYOUT;
  37
  38 module_param(timeout, int, 0);
  39 MODULE_PARM_DESC(timeout, "Watchdog time in seconds. (default="
  40                                 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
  41
  42 module_param(nowayout, bool, 0);
  43 MODULE_PARM_DESC(nowayout,
  44                 "Watchdog cannot be stopped once started (default="
  45                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  46
  47 static inline struct bcm47xx_wdt *bcm47xx_wdt_get(struct watchdog_device *wdd)
  48 {
  49         return container_of(wdd, struct bcm47xx_wdt, wdd);
  50 }
  51
  52 static int bcm47xx_wdt_hard_keepalive(struct watchdog_device *wdd)
  53 {
  54         struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
  55
  56         wdt->timer_set_ms(wdt, wdd->timeout * 1000);
  57
  58         return 0;
  59 }
  60
  61 static int bcm47xx_wdt_hard_start(struct watchdog_device *wdd)
  62 {
  63         return 0;
  64 }
  65
  66 static int bcm47xx_wdt_hard_stop(struct watchdog_device *wdd)
  67 {
  68         struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
  69
  70         wdt->timer_set(wdt, 0);
  71
  72         return 0;
  73 }
  74
  75 static int bcm47xx_wdt_hard_set_timeout(struct watchdog_device *wdd,
  76                                         unsigned int new_time)
  77 {
  78         struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
  79         u32 max_timer = wdt->max_timer_ms;
  80
  81         if (new_time < 1 || new_time > max_timer / 1000) {
  82                 pr_warn("timeout value must be 1<=x<=%d, using %d\n",
  83                         max_timer / 1000, new_time);
  84                 return -EINVAL;
  85         }
  86
  87         wdd->timeout = new_time;
  88         return 0;
  89 }
  90
  91 static struct watchdog_ops bcm47xx_wdt_hard_ops = {
  92         .owner          = THIS_MODULE,
  93         .start          = bcm47xx_wdt_hard_start,
  94         .stop           = bcm47xx_wdt_hard_stop,
  95         .ping           = bcm47xx_wdt_hard_keepalive,
  96         .set_timeout    = bcm47xx_wdt_hard_set_timeout,
  97 };
  98
  99 static void bcm47xx_wdt_soft_timer_tick(unsigned long data)
 100 {
 101         struct bcm47xx_wdt *wdt = (struct bcm47xx_wdt *)data;
 102         u32 next_tick = min(wdt->wdd.timeout * 1000, wdt->max_timer_ms);
 103
 104         if (!atomic_dec_and_test(&wdt->soft_ticks)) {
 105                 wdt->timer_set_ms(wdt, next_tick);
 106                 mod_timer(&wdt->soft_timer, jiffies + HZ);
 107         } else {
 108                 pr_crit("Watchdog will fire soon!!!\n");
 109         }
 110 }
 111
 112 static int bcm47xx_wdt_soft_keepalive(struct watchdog_device *wdd)
 113 {
 114         struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
 115
 116         atomic_set(&wdt->soft_ticks, wdd->timeout);
 117
 118         return 0;
 119 }
 120
 121 static int bcm47xx_wdt_soft_start(struct watchdog_device *wdd)
 122 {
 123         struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
 124
 125         bcm47xx_wdt_soft_keepalive(wdd);
 126         bcm47xx_wdt_soft_timer_tick((unsigned long)wdt);
 127
 128         return 0;
 129 }
 130
 131 static int bcm47xx_wdt_soft_stop(struct watchdog_device *wdd)
 132 {
 133         struct bcm47xx_wdt *wdt = bcm47xx_wdt_get(wdd);
 134
 135         del_timer_sync(&wdt->soft_timer);
 136         wdt->timer_set(wdt, 0);
 137
 138         return 0;
 139 }
 140
 141 static int bcm47xx_wdt_soft_set_timeout(struct watchdog_device *wdd,
 142                                         unsigned int new_time)
 143 {
 144         if (new_time < 1 || new_time > WDT_SOFTTIMER_MAX) {
 145                 pr_warn("timeout value must be 1<=x<=%d, using %d\n",
 146                         WDT_SOFTTIMER_MAX, new_time);
 147                 return -EINVAL;
 148         }
 149
 150         wdd->timeout = new_time;
 151         return 0;
 152 }
 153
 154 static const struct watchdog_info bcm47xx_wdt_info = {
 155         .identity       = DRV_NAME,
 156         .options        = WDIOF_SETTIMEOUT |
 157                                 WDIOF_KEEPALIVEPING |
 158                                 WDIOF_MAGICCLOSE,
 159 };
 160
 161 static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
 162                                   unsigned long code, void *unused)
 163 {
 164         struct bcm47xx_wdt *wdt;
 165
 166         wdt = container_of(this, struct bcm47xx_wdt, notifier);
 167         if (code == SYS_DOWN || code == SYS_HALT)
 168                 wdt->wdd.ops->stop(&wdt->wdd);
 169         return NOTIFY_DONE;
 170 }
 171
 172 static struct watchdog_ops bcm47xx_wdt_soft_ops = {
 173         .owner          = THIS_MODULE,
 174         .start          = bcm47xx_wdt_soft_start,
 175         .stop           = bcm47xx_wdt_soft_stop,
 176         .ping           = bcm47xx_wdt_soft_keepalive,
 177         .set_timeout    = bcm47xx_wdt_soft_set_timeout,
 178 };
 179
 180 static int bcm47xx_wdt_probe(struct platform_device *pdev)
 181 {
 182         int ret;
 183         bool soft;
 184         struct bcm47xx_wdt *wdt = dev_get_platdata(&pdev->dev);
 185
 186         if (!wdt)
 187                 return -ENXIO;
 188
 189         soft = wdt->max_timer_ms < WDT_SOFTTIMER_THRESHOLD * 1000;
 190
 191         if (soft) {
 192                 wdt->wdd.ops = &bcm47xx_wdt_soft_ops;
 193                 setup_timer(&wdt->soft_timer, bcm47xx_wdt_soft_timer_tick,
 194                             (long unsigned int)wdt);
 195         } else {
 196                 wdt->wdd.ops = &bcm47xx_wdt_hard_ops;
 197         }
 198
 199         wdt->wdd.info = &bcm47xx_wdt_info;
 200         wdt->wdd.timeout = WDT_DEFAULT_TIME;
 201         ret = wdt->wdd.ops->set_timeout(&wdt->wdd, timeout);
 202         if (ret)
 203                 goto err_timer;
 204         watchdog_set_nowayout(&wdt->wdd, nowayout);
 205
 206         wdt->notifier.notifier_call = &bcm47xx_wdt_notify_sys;
 207
 208         ret = register_reboot_notifier(&wdt->notifier);
 209         if (ret)
 210                 goto err_timer;
 211
 212         ret = watchdog_register_device(&wdt->wdd);
 213         if (ret)
 214                 goto err_notifier;
 215
 216         dev_info(&pdev->dev, "BCM47xx Watchdog Timer enabled (%d seconds%s%s)\n",
 217                 timeout, nowayout ? ", nowayout" : "",
 218                 soft ? ", Software Timer" : "");
 219         return 0;
 220
 221 err_notifier:
 222         unregister_reboot_notifier(&wdt->notifier);
 223 err_timer:
 224         if (soft)
 225                 del_timer_sync(&wdt->soft_timer);
 226
 227         return ret;
 228 }
 229
 230 static int bcm47xx_wdt_remove(struct platform_device *pdev)
 231 {
 232         struct bcm47xx_wdt *wdt = dev_get_platdata(&pdev->dev);
 233
 234         if (!wdt)
 235                 return -ENXIO;
 236
 237         watchdog_unregister_device(&wdt->wdd);
 238         unregister_reboot_notifier(&wdt->notifier);
 239
 240         return 0;
 241 }
 242
 243 static struct platform_driver bcm47xx_wdt_driver = {
 244         .driver         = {
 245                 .name   = "bcm47xx-wdt",
 246         },
 247         .probe          = bcm47xx_wdt_probe,
 248         .remove         = bcm47xx_wdt_remove,
 249 };
 250
 251 module_platform_driver(bcm47xx_wdt_driver);
 252
 253 MODULE_AUTHOR("Aleksandar Radovanovic");
 254 MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>");
 255 MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
 256 MODULE_LICENSE("GPL");