target/linux/ifxmips/files/drivers/watchdog/ifxmips_wdt.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  15  *
  16  * Copyright (C) 2008 John Crispin <blogic@openwrt.org>
  17  * Based on EP93xx wdt driver
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/fs.h>
  22 #include <linux/miscdevice.h>
  23 #include <linux/miscdevice.h>
  24 #include <linux/watchdog.h>
  25 #include <linux/platform_device.h>
  26 #include <asm/uaccess.h>
  27 #include <asm-mips/ifxmips/ifxmips_cgu.h>
  28 #include <asm-mips/ifxmips/ifxmips.h>
  29
  30 #define IFXMIPS_WDT_PW1                  0x00BE0000
  31 #define IFXMIPS_WDT_PW2                  0x00DC0000
  32
  33 #ifndef CONFIG_WATCHDOG_NOWAYOUT
  34 static int wdt_ok_to_close = 0;
  35 #endif
  36
  37 int wdt_timeout = 30;
  38
  39 int
  40 ifxmips_wdt_enable(unsigned int timeout)
  41 {
  42         u32 fpi;
  43         fpi = cgu_get_io_region_clock();
  44         ifxmips_w32(IFXMIPS_WDT_PW1, IFXMIPS_BIU_WDT_CR);
  45         ifxmips_w32(IFXMIPS_WDT_PW2 |
  46                 (0x3 << 26) | // PWL
  47                 (0x3 << 24) | // CLKDIV
  48                 (0x1 << 31) | // enable
  49                 ((timeout * (fpi / 0x40000)) + 0x1000), // reload
  50                 IFXMIPS_BIU_WDT_CR);
  51         return 0;
  52 }
  53
  54 void
  55 ifxmips_wdt_disable(void)
  56 {
  57 #ifndef CONFIG_WATCHDOG_NOWAYOUT
  58         wdt_ok_to_close = 0;
  59 #endif
  60         ifxmips_w32(IFXMIPS_WDT_PW1, IFXMIPS_BIU_WDT_CR);
  61         ifxmips_w32(IFXMIPS_WDT_PW2, IFXMIPS_BIU_WDT_CR);
  62 }
  63
  64 static ssize_t
  65 ifxmips_wdt_write(struct file *file, const char __user *data, size_t len,
  66                  loff_t *ppos)
  67 {
  68         size_t i;
  69
  70         if(!len)
  71                 return 0;
  72
  73 #ifndef CONFIG_WATCHDOG_NOWAYOUT
  74         for(i = 0; i != len; i++)
  75         {
  76                 char c;
  77                 if(get_user(c, data + i))
  78                         return -EFAULT;
  79                 if(c == 'V')
  80                         wdt_ok_to_close = 1;
  81         }
  82 #endif
  83         ifxmips_wdt_enable(wdt_timeout);
  84         return len;
  85 }
  86
  87 static struct watchdog_info ident = {
  88         .options = WDIOF_MAGICCLOSE,
  89         .identity = "ifxmips Watchdog",
  90 };
  91
  92 static int
  93 ifxmips_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
  94                  unsigned long arg)
  95 {
  96         int ret = -ENOTTY;
  97
  98         switch(cmd)
  99         {
 100         case WDIOC_GETSUPPORT:
 101                 ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
 102                                 sizeof(ident)) ? -EFAULT : 0;
 103                 break;
 104
 105         case WDIOC_GETTIMEOUT:
 106                 ret = put_user(wdt_timeout, (int __user *)arg);
 107                 break;
 108
 109         case WDIOC_SETTIMEOUT:
 110                 ret = get_user(wdt_timeout, (int __user*)arg);
 111                 break;
 112
 113         case WDIOC_KEEPALIVE:
 114                 ifxmips_wdt_enable(wdt_timeout);
 115                 ret = 0;
 116                 break;
 117         }
 118         return ret;
 119 }
 120
 121 static int
 122 ifxmips_wdt_open(struct inode *inode, struct file *file)
 123 {
 124         ifxmips_wdt_enable(wdt_timeout);
 125         return nonseekable_open(inode, file);
 126 }
 127
 128 static int ifxmips_wdt_release(struct inode *inode, struct file *file)
 129 {
 130 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 131         if(wdt_ok_to_close)
 132                 ifxmips_wdt_disable();
 133         else
 134 #endif
 135                 printk("ifxmips_wdt: watchdog closed without warning, rebooting system\n");
 136         return 0;
 137 }
 138
 139 static const struct file_operations ifxmips_wdt_fops = {
 140         .owner          = THIS_MODULE,
 141         .write          = ifxmips_wdt_write,
 142         .ioctl          = ifxmips_wdt_ioctl,
 143         .open           = ifxmips_wdt_open,
 144         .release        = ifxmips_wdt_release,
 145 };
 146
 147 static struct miscdevice ifxmips_wdt_miscdev = {
 148         .minor          = WATCHDOG_MINOR,
 149         .name           = "watchdog",
 150         .fops           = &ifxmips_wdt_fops,
 151 };
 152
 153 static int
 154 ifxmips_wdt_probe(struct platform_device *dev)
 155 {
 156         int err;
 157         err = misc_register(&ifxmips_wdt_miscdev);
 158         if(err)
 159                 printk("ifxmips_wdt: error creating device\n");
 160         else
 161                 printk("ifxmips_wdt: loaded\n");
 162         return err;
 163 }
 164
 165 static int
 166 ifxmips_wdt_remove(struct platform_device *dev)
 167 {
 168         ifxmips_wdt_disable();
 169         misc_deregister(&ifxmips_wdt_miscdev);
 170         return 0;
 171 }
 172
 173
 174 static struct platform_driver ifxmips_wdt_driver = {
 175         .probe = ifxmips_wdt_probe,
 176         .remove = ifxmips_wdt_remove,
 177         .driver = {
 178                 .name = "ifxmips_wdt",
 179                 .owner = THIS_MODULE,
 180         },
 181 };
 182
 183 static int __init
 184 init_ifxmips_wdt(void)
 185 {
 186         int ret = platform_driver_register(&ifxmips_wdt_driver);
 187         if(ret)
 188                 printk(KERN_INFO "ifxmips_wdt: error registering platfom driver!");
 189         return ret;
 190 }
 191
 192 static void __exit
 193 exit_ifxmips_wdt(void)
 194 {
 195         platform_driver_unregister(&ifxmips_wdt_driver);
 196 }
 197
 198 module_init(init_ifxmips_wdt);
 199 module_exit(exit_ifxmips_wdt);
 200
 201 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 202 MODULE_DESCRIPTION("ifxmips Watchdog");
 203 MODULE_LICENSE("GPL");
 204 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);