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 <linux/uaccess.h>
  27
  28 #include <asm/ifxmips/ifxmips_cgu.h>
  29 #include <asm/ifxmips/ifxmips.h>
  30
  31 #define IFXMIPS_WDT_PW1                 0x00BE0000
  32 #define IFXMIPS_WDT_PW2                 0x00DC0000
  33
  34 #ifndef CONFIG_WATCHDOG_NOWAYOUT
  35 static int wdt_ok_to_close;
  36 #endif
  37
  38 static int wdt_timeout = 30;
  39
  40 int 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 ifxmips_wdt_disable(void)
  55 {
  56 #ifndef CONFIG_WATCHDOG_NOWAYOUT
  57         wdt_ok_to_close = 0;
  58 #endif
  59         ifxmips_w32(IFXMIPS_WDT_PW1, IFXMIPS_BIU_WDT_CR);
  60         ifxmips_w32(IFXMIPS_WDT_PW2, IFXMIPS_BIU_WDT_CR);
  61 }
  62
  63 static ssize_t ifxmips_wdt_write(struct file *file, const char __user *data,
  64                 size_t len, loff_t *ppos)
  65 {
  66         size_t i;
  67
  68         if (!len)
  69                 return 0;
  70
  71 #ifndef CONFIG_WATCHDOG_NOWAYOUT
  72         for (i = 0; i != len; i++) {
  73                 char c;
  74                 if (get_user(c, data + i))
  75                         return -EFAULT;
  76                 if (c == 'V')
  77                         wdt_ok_to_close = 1;
  78         }
  79 #endif
  80         ifxmips_wdt_enable(wdt_timeout);
  81         return len;
  82 }
  83
  84 static struct watchdog_info ident = {
  85         .options = WDIOF_MAGICCLOSE,
  86         .identity = "ifxmips Watchdog",
  87 };
  88
  89 static int ifxmips_wdt_ioctl(struct inode *inode, struct file *file,
  90                 unsigned int cmd, unsigned long arg)
  91 {
  92         int ret = -ENOTTY;
  93
  94         switch (cmd) {
  95         case WDIOC_GETSUPPORT:
  96                 ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
  97                                 sizeof(ident)) ? -EFAULT : 0;
  98                 break;
  99
 100         case WDIOC_GETTIMEOUT:
 101                 ret = put_user(wdt_timeout, (int __user *)arg);
 102                 break;
 103
 104         case WDIOC_SETTIMEOUT:
 105                 ret = get_user(wdt_timeout, (int __user *)arg);
 106                 break;
 107
 108         case WDIOC_KEEPALIVE:
 109                 ifxmips_wdt_enable(wdt_timeout);
 110                 ret = 0;
 111                 break;
 112         }
 113         return ret;
 114 }
 115
 116 static int ifxmips_wdt_open(struct inode *inode, struct file *file)
 117 {
 118         ifxmips_wdt_enable(wdt_timeout);
 119         return nonseekable_open(inode, file);
 120 }
 121
 122 static int ifxmips_wdt_release(struct inode *inode, struct file *file)
 123 {
 124 #ifndef CONFIG_WATCHDOG_NOWAYOUT
 125         if (wdt_ok_to_close)
 126                 ifxmips_wdt_disable();
 127         else
 128 #endif
 129                 printk(KERN_ERR "ifxmips_wdt: watchdog closed without warning,"
 130                         " rebooting system\n");
 131         return 0;
 132 }
 133
 134 static const struct file_operations ifxmips_wdt_fops = {
 135         .owner          = THIS_MODULE,
 136         .write          = ifxmips_wdt_write,
 137         .ioctl          = ifxmips_wdt_ioctl,
 138         .open           = ifxmips_wdt_open,
 139         .release        = ifxmips_wdt_release,
 140 };
 141
 142 static struct miscdevice ifxmips_wdt_miscdev = {
 143         .minor          = WATCHDOG_MINOR,
 144         .name           = "watchdog",
 145         .fops           = &ifxmips_wdt_fops,
 146 };
 147
 148 static int ifxmips_wdt_probe(struct platform_device *dev)
 149 {
 150         int err;
 151         err = misc_register(&ifxmips_wdt_miscdev);
 152         if (err)
 153                 printk(KERN_INFO "ifxmips_wdt: error creating device\n");
 154         else
 155                 printk(KERN_INFO "ifxmips_wdt: loaded\n");
 156         return err;
 157 }
 158
 159 static int ifxmips_wdt_remove(struct platform_device *dev)
 160 {
 161         ifxmips_wdt_disable();
 162         misc_deregister(&ifxmips_wdt_miscdev);
 163         return 0;
 164 }
 165
 166
 167 static struct platform_driver ifxmips_wdt_driver = {
 168         .probe = ifxmips_wdt_probe,
 169         .remove = ifxmips_wdt_remove,
 170         .driver = {
 171                 .name = "ifxmips_wdt",
 172                 .owner = THIS_MODULE,
 173         },
 174 };
 175
 176 static int __init init_ifxmips_wdt(void)
 177 {
 178         int ret = platform_driver_register(&ifxmips_wdt_driver);
 179         if (ret)
 180                 printk(KERN_INFO "ifxmips_wdt: error registering platfom driver!");
 181         return ret;
 182 }
 183
 184 static void __exit exit_ifxmips_wdt(void)
 185 {
 186         platform_driver_unregister(&ifxmips_wdt_driver);
 187 }
 188
 189 module_init(init_ifxmips_wdt);
 190 module_exit(exit_ifxmips_wdt);
 191
 192 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 193 MODULE_DESCRIPTION("ifxmips Watchdog");
 194 MODULE_LICENSE("GPL");
 195 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);