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