target/linux/atheros/files-2.6.28/drivers/watchdog/ar2315-wtd.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 and ifxmips wdt driver
  18  */
  19
  20 #include <linux/interrupt.h>
  21 #include <linux/module.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/types.h>
  24 #include <linux/miscdevice.h>
  25 #include <linux/watchdog.h>
  26 #include <linux/fs.h>
  27 #include <linux/ioport.h>
  28 #include <linux/notifier.h>
  29 #include <linux/reboot.h>
  30 #include <linux/init.h>
  31 #include <linux/platform_device.h>
  32
  33 #include <asm/io.h>
  34 #include <asm/uaccess.h>
  35 #include <asm/system.h>
  36 #include <asm/addrspace.h>
  37 #include <ar531x.h>
  38
  39 #define CLOCK_RATE 40000000
  40 #define HEARTBEAT(x) (x < 1 || x > 90)?(20):(x)
  41
  42 static int wdt_timeout = 20;
  43 static int started = 0;
  44 static int in_use = 0;
  45
  46 static void
  47 ar2315_wdt_enable(void)
  48 {
  49         sysRegWrite(AR5315_WD, wdt_timeout * CLOCK_RATE);
  50         sysRegWrite(AR5315_ISR, 0x80);
  51 }
  52
  53 static ssize_t
  54 ar2315_wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos)
  55 {
  56         if(len)
  57                 ar2315_wdt_enable();
  58         return len;
  59 }
  60
  61 static int
  62 ar2315_wdt_open(struct inode *inode, struct file *file)
  63 {
  64         if(in_use)
  65                 return -EBUSY;
  66         ar2315_wdt_enable();
  67         in_use = started = 1;
  68         return nonseekable_open(inode, file);
  69 }
  70
  71 static int
  72 ar2315_wdt_release(struct inode *inode, struct file *file)
  73 {
  74         in_use = 0;
  75         return 0;
  76 }
  77
  78 static irqreturn_t
  79 ar2315_wdt_interrupt(int irq, void *dev_id)
  80 {
  81         if(started)
  82         {
  83                 printk(KERN_CRIT "watchdog expired, rebooting system\n");
  84                 emergency_restart();
  85         } else {
  86                 sysRegWrite(AR5315_WDC, 0);
  87                 sysRegWrite(AR5315_WD, 0);
  88                 sysRegWrite(AR5315_ISR, 0x80);
  89         }
  90         return IRQ_HANDLED;
  91 }
  92
  93 static struct watchdog_info ident = {
  94         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
  95         .identity = "ar2315 Watchdog",
  96 };
  97
  98 static int
  99 ar2315_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 100 {
 101         int new_wdt_timeout;
 102         int ret = -ENOIOCTLCMD;
 103
 104         switch(cmd)
 105         {
 106                 case WDIOC_GETSUPPORT:
 107                         ret = copy_to_user((struct watchdog_info __user *)arg, &ident, sizeof(ident)) ? -EFAULT : 0;
 108                         break;
 109
 110                 case WDIOC_KEEPALIVE:
 111                         ar2315_wdt_enable();
 112                         ret = 0;
 113                         break;
 114
 115                 case WDIOC_SETTIMEOUT:
 116                         if((ret = get_user(new_wdt_timeout, (int __user *)arg)))
 117                                 break;
 118                         wdt_timeout = HEARTBEAT(new_wdt_timeout);
 119                         ar2315_wdt_enable();
 120                         break;
 121
 122                 case WDIOC_GETTIMEOUT:
 123                         ret = put_user(wdt_timeout, (int __user *)arg);
 124                         break;
 125         }
 126         return ret;
 127 }
 128
 129 static struct file_operations ar2315_wdt_fops = {
 130         .owner          = THIS_MODULE,
 131         .llseek         = no_llseek,
 132         .write          = ar2315_wdt_write,
 133         .ioctl          = ar2315_wdt_ioctl,
 134         .open           = ar2315_wdt_open,
 135         .release        = ar2315_wdt_release,
 136 };
 137
 138 static struct miscdevice ar2315_wdt_miscdev = {
 139         .minor  = WATCHDOG_MINOR,
 140         .name   = "watchdog",
 141         .fops   = &ar2315_wdt_fops,
 142 };
 143
 144 static int
 145 ar2315_wdt_probe(struct platform_device *dev)
 146 {
 147         int ret = 0;
 148
 149         ar2315_wdt_enable();
 150         ret = request_irq(AR531X_MISC_IRQ_WATCHDOG, ar2315_wdt_interrupt, IRQF_DISABLED, "ar2315_wdt", NULL);
 151         if(ret)
 152         {
 153                 printk(KERN_ERR "ar2315wdt: failed to register inetrrupt\n");
 154                 goto out;
 155         }
 156
 157         ret = misc_register(&ar2315_wdt_miscdev);
 158         if(ret)
 159                 printk(KERN_ERR "ar2315wdt: failed to register miscdev\n");
 160
 161 out:
 162         return ret;
 163 }
 164
 165 static int
 166 ar2315_wdt_remove(struct platform_device *dev)
 167 {
 168         misc_deregister(&ar2315_wdt_miscdev);
 169         free_irq(AR531X_MISC_IRQ_WATCHDOG, NULL);
 170         return 0;
 171 }
 172
 173 static struct platform_driver ar2315_wdt_driver = {
 174         .probe = ar2315_wdt_probe,
 175         .remove = ar2315_wdt_remove,
 176         .driver = {
 177                 .name = "ar2315_wdt",
 178                 .owner = THIS_MODULE,
 179         },
 180 };
 181
 182 static int __init
 183 init_ar2315_wdt(void)
 184 {
 185         int ret = platform_driver_register(&ar2315_wdt_driver);
 186         if(ret)
 187                 printk(KERN_INFO "ar2315_wdt: error registering platfom driver!");
 188         return ret;
 189 }
 190
 191 static void __exit
 192 exit_ar2315_wdt(void)
 193 {
 194         platform_driver_unregister(&ar2315_wdt_driver);
 195 }
 196
 197 module_init(init_ar2315_wdt);
 198 module_exit(exit_ar2315_wdt);