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/fs.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/miscdevice.h>
  21 #include <linux/module.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/reboot.h>
  24 #include <linux/types.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/watchdog.h>
  27 #include <linux/timer.h>
  28 #include <linux/jiffies.h>
  29 #include <linux/ssb/ssb_embedded.h>
  30 #include <asm/mach-bcm47xx/bcm47xx.h>
  31
  32 #define DRV_NAME                "bcm47xx_wdt"
  33
  34 #define WDT_DEFAULT_TIME        30      /* seconds */
  35 #define WDT_MAX_TIME            255     /* seconds */
  36
  37 static int wdt_time = WDT_DEFAULT_TIME;
  38 static bool nowayout = WATCHDOG_NOWAYOUT;
  39
  40 module_param(wdt_time, int, 0);
  41 MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
  42                                 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
  43
  44 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  45 module_param(nowayout, bool, 0);
  46 MODULE_PARM_DESC(nowayout,
  47                 "Watchdog cannot be stopped once started (default="
  48                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  49 #endif
  50
  51 static unsigned long bcm47xx_wdt_busy;
  52 static char expect_release;
  53 static struct timer_list wdt_timer;
  54 static atomic_t ticks;
  55
  56 static inline void bcm47xx_wdt_hw_start(void)
  57 {
  58         /* this is 2,5s on 100Mhz clock  and 2s on 133 Mhz */
  59         switch (bcm47xx_bus_type) {
  60 #ifdef CONFIG_BCM47XX_SSB
  61         case BCM47XX_BUS_TYPE_SSB:
  62                 ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0xfffffff);
  63                 break;
  64 #endif
  65 #ifdef CONFIG_BCM47XX_BCMA
  66         case BCM47XX_BUS_TYPE_BCMA:
  67                 bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc,
  68                                                0xfffffff);
  69                 break;
  70 #endif
  71         }
  72 }
  73
  74 static inline int bcm47xx_wdt_hw_stop(void)
  75 {
  76         switch (bcm47xx_bus_type) {
  77 #ifdef CONFIG_BCM47XX_SSB
  78         case BCM47XX_BUS_TYPE_SSB:
  79                 return ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0);
  80 #endif
  81 #ifdef CONFIG_BCM47XX_BCMA
  82         case BCM47XX_BUS_TYPE_BCMA:
  83                 bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc, 0);
  84                 return 0;
  85 #endif
  86         }
  87         return -EINVAL;
  88 }
  89
  90 static void bcm47xx_timer_tick(unsigned long unused)
  91 {
  92         if (!atomic_dec_and_test(&ticks)) {
  93                 bcm47xx_wdt_hw_start();
  94                 mod_timer(&wdt_timer, jiffies + HZ);
  95         } else {
  96                 pr_crit("Watchdog will fire soon!!!\n");
  97         }
  98 }
  99
 100 static inline void bcm47xx_wdt_pet(void)
 101 {
 102         atomic_set(&ticks, wdt_time);
 103 }
 104
 105 static void bcm47xx_wdt_start(void)
 106 {
 107         bcm47xx_wdt_pet();
 108         bcm47xx_timer_tick(0);
 109 }
 110
 111 static void bcm47xx_wdt_pause(void)
 112 {
 113         del_timer_sync(&wdt_timer);
 114         bcm47xx_wdt_hw_stop();
 115 }
 116
 117 static void bcm47xx_wdt_stop(void)
 118 {
 119         bcm47xx_wdt_pause();
 120 }
 121
 122 static int bcm47xx_wdt_settimeout(int new_time)
 123 {
 124         if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
 125                 return -EINVAL;
 126
 127         wdt_time = new_time;
 128         return 0;
 129 }
 130
 131 static int bcm47xx_wdt_open(struct inode *inode, struct file *file)
 132 {
 133         if (test_and_set_bit(0, &bcm47xx_wdt_busy))
 134                 return -EBUSY;
 135
 136         bcm47xx_wdt_start();
 137         return nonseekable_open(inode, file);
 138 }
 139
 140 static int bcm47xx_wdt_release(struct inode *inode, struct file *file)
 141 {
 142         if (expect_release == 42) {
 143                 bcm47xx_wdt_stop();
 144         } else {
 145                 pr_crit("Unexpected close, not stopping watchdog!\n");
 146                 bcm47xx_wdt_start();
 147         }
 148
 149         clear_bit(0, &bcm47xx_wdt_busy);
 150         expect_release = 0;
 151         return 0;
 152 }
 153
 154 static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data,
 155                                 size_t len, loff_t *ppos)
 156 {
 157         if (len) {
 158                 if (!nowayout) {
 159                         size_t i;
 160
 161                         expect_release = 0;
 162
 163                         for (i = 0; i != len; i++) {
 164                                 char c;
 165                                 if (get_user(c, data + i))
 166                                         return -EFAULT;
 167                                 if (c == 'V')
 168                                         expect_release = 42;
 169                         }
 170                 }
 171                 bcm47xx_wdt_pet();
 172         }
 173         return len;
 174 }
 175
 176 static const struct watchdog_info bcm47xx_wdt_info = {
 177         .identity       = DRV_NAME,
 178         .options        = WDIOF_SETTIMEOUT |
 179                                 WDIOF_KEEPALIVEPING |
 180                                 WDIOF_MAGICCLOSE,
 181 };
 182
 183 static long bcm47xx_wdt_ioctl(struct file *file,
 184                                         unsigned int cmd, unsigned long arg)
 185 {
 186         void __user *argp = (void __user *)arg;
 187         int __user *p = argp;
 188         int new_value, retval = -EINVAL;
 189
 190         switch (cmd) {
 191         case WDIOC_GETSUPPORT:
 192                 return copy_to_user(argp, &bcm47xx_wdt_info,
 193                                 sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0;
 194
 195         case WDIOC_GETSTATUS:
 196         case WDIOC_GETBOOTSTATUS:
 197                 return put_user(0, p);
 198
 199         case WDIOC_SETOPTIONS:
 200                 if (get_user(new_value, p))
 201                         return -EFAULT;
 202
 203                 if (new_value & WDIOS_DISABLECARD) {
 204                         bcm47xx_wdt_stop();
 205                         retval = 0;
 206                 }
 207
 208                 if (new_value & WDIOS_ENABLECARD) {
 209                         bcm47xx_wdt_start();
 210                         retval = 0;
 211                 }
 212
 213                 return retval;
 214
 215         case WDIOC_KEEPALIVE:
 216                 bcm47xx_wdt_pet();
 217                 return 0;
 218
 219         case WDIOC_SETTIMEOUT:
 220                 if (get_user(new_value, p))
 221                         return -EFAULT;
 222
 223                 if (bcm47xx_wdt_settimeout(new_value))
 224                         return -EINVAL;
 225
 226                 bcm47xx_wdt_pet();
 227
 228         case WDIOC_GETTIMEOUT:
 229                 return put_user(wdt_time, p);
 230
 231         default:
 232                 return -ENOTTY;
 233         }
 234 }
 235
 236 static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
 237         unsigned long code, void *unused)
 238 {
 239         if (code == SYS_DOWN || code == SYS_HALT)
 240                 bcm47xx_wdt_stop();
 241         return NOTIFY_DONE;
 242 }
 243
 244 static const struct file_operations bcm47xx_wdt_fops = {
 245         .owner          = THIS_MODULE,
 246         .llseek         = no_llseek,
 247         .unlocked_ioctl = bcm47xx_wdt_ioctl,
 248         .open           = bcm47xx_wdt_open,
 249         .release        = bcm47xx_wdt_release,
 250         .write          = bcm47xx_wdt_write,
 251 };
 252
 253 static struct miscdevice bcm47xx_wdt_miscdev = {
 254         .minor          = WATCHDOG_MINOR,
 255         .name           = "watchdog",
 256         .fops           = &bcm47xx_wdt_fops,
 257 };
 258
 259 static struct notifier_block bcm47xx_wdt_notifier = {
 260         .notifier_call = bcm47xx_wdt_notify_sys,
 261 };
 262
 263 static int __init bcm47xx_wdt_init(void)
 264 {
 265         int ret;
 266
 267         if (bcm47xx_wdt_hw_stop() < 0)
 268                 return -ENODEV;
 269
 270         setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L);
 271
 272         if (bcm47xx_wdt_settimeout(wdt_time)) {
 273                 bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME);
 274                 pr_info("wdt_time value must be 0 < wdt_time < %d, using %d\n",
 275                         (WDT_MAX_TIME + 1), wdt_time);
 276         }
 277
 278         ret = register_reboot_notifier(&bcm47xx_wdt_notifier);
 279         if (ret)
 280                 return ret;
 281
 282         ret = misc_register(&bcm47xx_wdt_miscdev);
 283         if (ret) {
 284                 unregister_reboot_notifier(&bcm47xx_wdt_notifier);
 285                 return ret;
 286         }
 287
 288         pr_info("BCM47xx Watchdog Timer enabled (%d seconds%s)\n",
 289                 wdt_time, nowayout ? ", nowayout" : "");
 290         return 0;
 291 }
 292
 293 static void __exit bcm47xx_wdt_exit(void)
 294 {
 295         if (!nowayout)
 296                 bcm47xx_wdt_stop();
 297
 298         misc_deregister(&bcm47xx_wdt_miscdev);
 299
 300         unregister_reboot_notifier(&bcm47xx_wdt_notifier);
 301 }
 302
 303 module_init(bcm47xx_wdt_init);
 304 module_exit(bcm47xx_wdt_exit);
 305
 306 MODULE_AUTHOR("Aleksandar Radovanovic");
 307 MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
 308 MODULE_LICENSE("GPL");
 309 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);