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  *
   7  *  This program is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU General Public License
   9  *  as published by the Free Software Foundation; either version
  10  *  2 of the License, or (at your option) any later version.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/bitops.h>
  16 #include <linux/errno.h>
  17 #include <linux/init.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/moduleparam.h>
  21 #include <linux/reboot.h>
  22 #include <linux/types.h>
  23 #include <linux/watchdog.h>
  24 #include <linux/timer.h>
  25 #include <linux/jiffies.h>
  26 #include <linux/ssb/ssb_embedded.h>
  27 #include <asm/mach-bcm47xx/bcm47xx.h>
  28
  29 #define DRV_NAME                "bcm47xx_wdt"
  30
  31 #define WDT_DEFAULT_TIME        30      /* seconds */
  32 #define WDT_MAX_TIME            255     /* seconds */
  33
  34 static int wdt_time = WDT_DEFAULT_TIME;
  35 static bool nowayout = WATCHDOG_NOWAYOUT;
  36
  37 module_param(wdt_time, int, 0);
  38 MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
  39                                 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
  40
  41 module_param(nowayout, bool, 0);
  42 MODULE_PARM_DESC(nowayout,
  43                 "Watchdog cannot be stopped once started (default="
  44                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  45
  46 static struct timer_list wdt_timer;
  47 static atomic_t ticks;
  48
  49 static inline void bcm47xx_wdt_hw_start(void)
  50 {
  51         /* this is 2,5s on 100Mhz clock  and 2s on 133 Mhz */
  52         switch (bcm47xx_bus_type) {
  53 #ifdef CONFIG_BCM47XX_SSB
  54         case BCM47XX_BUS_TYPE_SSB:
  55                 ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0xfffffff);
  56                 break;
  57 #endif
  58 #ifdef CONFIG_BCM47XX_BCMA
  59         case BCM47XX_BUS_TYPE_BCMA:
  60                 bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc,
  61                                                0xfffffff);
  62                 break;
  63 #endif
  64         }
  65 }
  66
  67 static inline int bcm47xx_wdt_hw_stop(void)
  68 {
  69         switch (bcm47xx_bus_type) {
  70 #ifdef CONFIG_BCM47XX_SSB
  71         case BCM47XX_BUS_TYPE_SSB:
  72                 return ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0);
  73 #endif
  74 #ifdef CONFIG_BCM47XX_BCMA
  75         case BCM47XX_BUS_TYPE_BCMA:
  76                 bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc, 0);
  77                 return 0;
  78 #endif
  79         }
  80         return -EINVAL;
  81 }
  82
  83 static void bcm47xx_timer_tick(unsigned long unused)
  84 {
  85         if (!atomic_dec_and_test(&ticks)) {
  86                 bcm47xx_wdt_hw_start();
  87                 mod_timer(&wdt_timer, jiffies + HZ);
  88         } else {
  89                 pr_crit("Watchdog will fire soon!!!\n");
  90         }
  91 }
  92
  93 static int bcm47xx_wdt_keepalive(struct watchdog_device *wdd)
  94 {
  95         atomic_set(&ticks, wdt_time);
  96
  97         return 0;
  98 }
  99
 100 static int bcm47xx_wdt_start(struct watchdog_device *wdd)
 101 {
 102         bcm47xx_wdt_pet();
 103         bcm47xx_timer_tick(0);
 104
 105         return 0;
 106 }
 107
 108 static int bcm47xx_wdt_stop(struct watchdog_device *wdd)
 109 {
 110         del_timer_sync(&wdt_timer);
 111         bcm47xx_wdt_hw_stop();
 112
 113         return 0;
 114 }
 115
 116 static int bcm47xx_wdt_set_timeout(struct watchdog_device *wdd,
 117                                    unsigned int new_time)
 118 {
 119         if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
 120                 return -EINVAL;
 121
 122         wdt_time = new_time;
 123         return 0;
 124 }
 125
 126 static const struct watchdog_info bcm47xx_wdt_info = {
 127         .identity       = DRV_NAME,
 128         .options        = WDIOF_SETTIMEOUT |
 129                                 WDIOF_KEEPALIVEPING |
 130                                 WDIOF_MAGICCLOSE,
 131 };
 132
 133 static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
 134                                   unsigned long code, void *unused)
 135 {
 136         if (code == SYS_DOWN || code == SYS_HALT)
 137                 bcm47xx_wdt_stop();
 138         return NOTIFY_DONE;
 139 }
 140
 141 static struct watchdog_ops bcm47xx_wdt_ops = {
 142         .owner          = THIS_MODULE,
 143         .start          = bcm47xx_wdt_start,
 144         .stop           = bcm47xx_wdt_stop,
 145         .ping           = bcm47xx_wdt_keepalive,
 146         .set_timeout    = bcm47xx_wdt_set_timeout,
 147 };
 148
 149 static struct watchdog_device bcm47xx_wdt_wdd = {
 150         .info           = &bcm47xx_wdt_info,
 151         .ops            = &bcm47xx_wdt_ops,
 152 };
 153
 154 static struct notifier_block bcm47xx_wdt_notifier = {
 155         .notifier_call = bcm47xx_wdt_notify_sys,
 156 };
 157
 158 static int __init bcm47xx_wdt_init(void)
 159 {
 160         int ret;
 161
 162         if (bcm47xx_wdt_hw_stop() < 0)
 163                 return -ENODEV;
 164
 165         setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L);
 166
 167         if (bcm47xx_wdt_settimeout(wdt_time)) {
 168                 bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME);
 169                 pr_info("wdt_time value must be 0 < wdt_time < %d, using %d\n",
 170                         (WDT_MAX_TIME + 1), wdt_time);
 171         }
 172         watchdog_set_nowayout(&bcm47xx_wdt_wdd, nowayout);
 173
 174         ret = register_reboot_notifier(&bcm47xx_wdt_notifier);
 175         if (ret)
 176                 return ret;
 177
 178         ret = watchdog_register_device(&bcm47xx_wdt_wdd);
 179         if (ret) {
 180                 unregister_reboot_notifier(&bcm47xx_wdt_notifier);
 181                 return ret;
 182         }
 183
 184         pr_info("BCM47xx Watchdog Timer enabled (%d seconds%s)\n",
 185                 wdt_time, nowayout ? ", nowayout" : "");
 186         return 0;
 187 }
 188
 189 static void __exit bcm47xx_wdt_exit(void)
 190 {
 191         watchdog_unregister_device(&bcm47xx_wdt_wdd);
 192
 193         unregister_reboot_notifier(&bcm47xx_wdt_notifier);
 194 }
 195
 196 module_init(bcm47xx_wdt_init);
 197 module_exit(bcm47xx_wdt_exit);
 198
 199 MODULE_AUTHOR("Aleksandar Radovanovic");
 200 MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
 201 MODULE_LICENSE("GPL");