target/linux/rb532/files-2.6.23/drivers/char/watchdog/rc32434_wdt.c

   1 /*
   2  *      RC32434_WDT 0.01: IDT Interprise 79RC32434 watchdog driver
   3  *      Copyright (c) Ondrej Zajicek <santiago@crfreenet.org>, 2006
   4  *
   5  *      based on
   6  *
   7  *      SoftDog 0.05:   A Software Watchdog Device
   8  *
   9  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  10  *
  11  *      This program is free software; you can redistribute it and/or
  12  *      modify it under the terms of the GNU General Public License
  13  *      as published by the Free Software Foundation; either version
  14  *      2 of the License, or (at your option) any later version.
  15  *
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/types.h>
  20 #include <linux/kernel.h>
  21 #include <linux/fs.h>
  22 #include <linux/mm.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/watchdog.h>
  25 #include <linux/reboot.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/init.h>
  28 #include <asm/bootinfo.h>
  29 #include <asm/time.h>
  30 #include <asm/uaccess.h>
  31 #include <asm/rc32434/integ.h>
  32
  33 #define DEFAULT_TIMEOUT 15              /* (secs) Default is 15 seconds */
  34 #define MAX_TIMEOUT     20
  35 /*
  36  * (secs) Max is 20 seconds
  37  * (max frequency of counter is ~200 MHz, counter is 32-bit unsigned int)
  38  */
  39
  40 #define NAME "rc32434_wdt"
  41 #define VERSION "0.1"
  42
  43 static INTEG_t rc_wdt = (INTEG_t) INTEG_VirtualAddress;
  44
  45 static int expect_close = 0;
  46 static int access = 0;
  47 static int timeout = 0;
  48
  49 static int nowayout = WATCHDOG_NOWAYOUT;
  50 module_param(nowayout, int, 0);
  51 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  52 MODULE_LICENSE("GPL");
  53
  54
  55 static inline void start_wdt(void)
  56 {
  57         rc_wdt -> wtcount = 0;
  58         rc_wdt -> errcs |= ERRCS_wre_m;
  59         rc_wdt -> wtc   |= WTC_en_m;
  60 }
  61
  62 static inline void stop_wdt(void)
  63 {
  64         rc_wdt -> wtc   &= ~WTC_en_m;
  65         rc_wdt -> errcs &= ~ERRCS_wre_m;
  66 }
  67
  68 static inline void set_wdt(int new_timeout)
  69 {
  70         u32 cmp = new_timeout * mips_hpt_frequency;
  71         u32 state;
  72
  73         timeout = new_timeout;
  74         /*
  75          * store and disable WTC
  76          */
  77         state = rc_wdt -> wtc & WTC_en_m;
  78         rc_wdt -> wtc   &= ~WTC_en_m;
  79
  80         rc_wdt -> wtcount = 0;
  81         rc_wdt -> wtcompare = cmp;
  82
  83         /*
  84          * restore WTC
  85          */
  86         rc_wdt -> wtc |= state;
  87 }
  88
  89 static inline void update_wdt(void)
  90 {
  91         rc_wdt -> wtcount = 0;
  92 }
  93
  94 /*
  95  *      Allow only one person to hold it open
  96  */
  97
  98 static int wdt_open(struct inode *inode, struct file *file)
  99 {
 100         if (access)
 101                 return -EBUSY;
 102         if (nowayout) {
 103                 __module_get(THIS_MODULE);
 104         }
 105         /*
 106          *      Activate timer
 107          */
 108         start_wdt();
 109         printk(KERN_INFO NAME ": enabling watchdog timer\n");
 110         access = 1;
 111         return 0;
 112 }
 113
 114 static int wdt_release(struct inode *inode, struct file *file)
 115 {
 116         /*
 117          *      Shut off the timer.
 118          *      Lock it in if it's a module and we set nowayout
 119          */
 120         if (expect_close && nowayout == 0) {
 121                 stop_wdt ();
 122                 printk(KERN_INFO NAME ": disabling watchdog timer\n");
 123                 module_put(THIS_MODULE);
 124         } else {
 125                 printk (KERN_CRIT NAME ": device closed unexpectedly.  WDT will not stop!\n");
 126         }
 127         access = 0;
 128         return 0;
 129 }
 130
 131 static ssize_t wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
 132 {
 133         /*
 134          *      Refresh the timer.
 135          */
 136         if (len) {
 137                 if (!nowayout) {
 138                         size_t i;
 139
 140                         /* In case it was set long ago */
 141                         expect_close = 0;
 142
 143                         for (i = 0; i != len; i++) {
 144                                 char c;
 145                                 if (get_user(c, data + i))
 146                                         return -EFAULT;
 147                                 if (c == 'V')
 148                                         expect_close = 1;
 149                         }
 150                 }
 151                 update_wdt ();
 152                 return len;
 153         }
 154         return 0;
 155 }
 156
 157 static int wdt_ioctl(struct inode *inode, struct file *file,
 158         unsigned int cmd, unsigned long arg)
 159 {
 160         int new_timeout;
 161         static struct watchdog_info ident = {
 162                 .options =              WDIOF_SETTIMEOUT |
 163                                         WDIOF_KEEPALIVEPING |
 164                                         WDIOF_MAGICCLOSE,
 165                 .firmware_version =     0,
 166                 .identity =             "RC32434_WDT Watchdog",
 167         };
 168         switch (cmd) {
 169                 default:
 170                         return -ENOTTY;
 171                 case WDIOC_GETSUPPORT:
 172                         if(copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)))
 173                                 return -EFAULT;
 174                         return 0;
 175                 case WDIOC_GETSTATUS:
 176                 case WDIOC_GETBOOTSTATUS:
 177                         return put_user(0,(int *)arg);
 178                 case WDIOC_KEEPALIVE:
 179                         update_wdt();
 180                         return 0;
 181                 case WDIOC_SETTIMEOUT:
 182                         if (get_user(new_timeout, (int *)arg))
 183                                 return -EFAULT;
 184                         if (new_timeout < 1)
 185                                 return -EINVAL;
 186                         if (new_timeout > MAX_TIMEOUT)
 187                                 return -EINVAL;
 188                         set_wdt(new_timeout);
 189                         /* Fall */
 190                 case WDIOC_GETTIMEOUT:
 191                         return put_user(timeout, (int *)arg);
 192         }
 193 }
 194
 195 static struct file_operations wdt_fops = {
 196         owner:          THIS_MODULE,
 197         llseek:         no_llseek,
 198         write:          wdt_write,
 199         ioctl:          wdt_ioctl,
 200         open:           wdt_open,
 201         release:        wdt_release,
 202 };
 203
 204 static struct miscdevice wdt_miscdev = {
 205         minor:          WATCHDOG_MINOR,
 206         name:           "watchdog",
 207         fops:           &wdt_fops,
 208 };
 209
 210 static char banner[] __initdata = KERN_INFO NAME ": Watchdog Timer version " VERSION ", timer margin: %d sec\n";
 211
 212 static int __init watchdog_init(void)
 213 {
 214         int ret;
 215
 216         /*
 217          * There should be check for RC32434 SoC
 218          */
 219         if (mips_machgroup != MACH_GROUP_MIKROTIK) return -1;
 220
 221         ret = misc_register(&wdt_miscdev);
 222
 223         if (ret)
 224                 return ret;
 225
 226         stop_wdt();
 227         set_wdt(DEFAULT_TIMEOUT);
 228
 229         printk(banner, timeout);
 230
 231         return 0;
 232 }
 233
 234 static void __exit watchdog_exit(void)
 235 {
 236         misc_deregister(&wdt_miscdev);
 237 }
 238
 239 module_init(watchdog_init);
 240 module_exit(watchdog_exit);