drivers/char/watchdog/mtx-1_wdt.c

   1 /*
   2  *      Driver for the MTX-1 Watchdog.
   3  *
   4  *      (C) Copyright 2005 4G Systems <info@4g-systems.biz>, All Rights Reserved.
   5  *                              http://www.4g-systems.biz
   6  *
   7  *      (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org>
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  *
  14  *      Neither Michael Stickel nor 4G Systems admit liability nor provide
  15  *      warranty for any of this software. This material is provided
  16  *      "AS-IS" and at no charge.
  17  *
  18  *      (c) Copyright 2005    4G Systems <info@4g-systems.biz>
  19  *
  20  *      Release 0.01.
  21  *      Author: Michael Stickel  michael.stickel@4g-systems.biz
  22  *
  23  *      Release 0.02.
  24  *      Author: Florian Fainelli florian@openwrt.org
  25  *              use the Linux watchdog/timer APIs
  26  *
  27  *      The Watchdog is configured to reset the MTX-1
  28  *      if it is not triggered for 100 seconds.
  29  *      It should not be triggered more often than 1.6 seconds.
  30  *
  31  *      A timer triggers the watchdog every 5 seconds, until
  32  *      it is opened for the first time. After the first open
  33  *      it MUST be triggered every 2..95 seconds.
  34  */
  35
  36 #include <linux/module.h>
  37 #include <linux/moduleparam.h>
  38 #include <linux/types.h>
  39 #include <linux/errno.h>
  40 #include <linux/miscdevice.h>
  41 #include <linux/fs.h>
  42 #include <linux/init.h>
  43 #include <linux/ioport.h>
  44 #include <linux/timer.h>
  45 #include <linux/completion.h>
  46 #include <linux/jiffies.h>
  47 #include <linux/watchdog.h>
  48 #include <asm/io.h>
  49 #include <asm/uaccess.h>
  50
  51 #include <asm/mach-au1x00/au1000.h>
  52
  53 #define MTX1_WDT_INTERVAL       (5 * HZ)
  54
  55 static int ticks = 100 * HZ;
  56
  57 static struct {
  58         struct completion stop;
  59         volatile int running;
  60         struct timer_list timer;
  61         volatile int queue;
  62         int default_ticks;
  63         unsigned long inuse;
  64 } mtx1_wdt_device;
  65
  66 static void mtx1_wdt_trigger(unsigned long unused)
  67 {
  68         u32 tmp;
  69
  70         if (mtx1_wdt_device.running)
  71                 ticks--;
  72         /*
  73          * toggle GPIO2_15
  74          */
  75         tmp = au_readl(GPIO2_DIR);
  76         tmp = (tmp & ~(1<<15)) | ((~tmp) & (1<<15));
  77         au_writel (tmp, GPIO2_DIR);
  78
  79         if (mtx1_wdt_device.queue && ticks)
  80                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
  81         else {
  82                 complete(&mtx1_wdt_device.stop);
  83         }
  84 }
  85
  86 static void mtx1_wdt_reset(void)
  87 {
  88         ticks = mtx1_wdt_device.default_ticks;
  89 }
  90
  91
  92 static void mtx1_wdt_start(void)
  93 {
  94         if (!mtx1_wdt_device.queue) {
  95                 mtx1_wdt_device.queue = 1;
  96                 au_writel (au_readl(GPIO2_DIR) | (u32)(1<<15), GPIO2_DIR);
  97                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
  98         }
  99         mtx1_wdt_device.running++;
 100 }
 101
 102 static int mtx1_wdt_stop(void)
 103 {
 104         if (mtx1_wdt_device.queue) {
 105                 mtx1_wdt_device.queue = 0;
 106                 au_writel (au_readl(GPIO2_DIR) & ~((u32)(1<<15)), GPIO2_DIR);
 107         }
 108
 109         ticks = mtx1_wdt_device.default_ticks;
 110
 111         return 0;
 112 }
 113
 114 /* Filesystem functions */
 115
 116 static int mtx1_wdt_open(struct inode *inode, struct file *file)
 117 {
 118         if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
 119                 return -EBUSY;
 120
 121         return nonseekable_open(inode, file);
 122 }
 123
 124
 125 static int mtx1_wdt_release(struct inode *inode, struct file *file)
 126 {
 127         clear_bit(0, &mtx1_wdt_device.inuse);
 128         return 0;
 129 }
 130
 131 static int mtx1_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 132 {
 133         void __user *argp = (void __user *)arg;
 134         unsigned int value;
 135         static struct watchdog_info ident =
 136         {
 137                 .options = WDIOF_CARDRESET,
 138                 .identity = "MTX-1 WDT",
 139         };
 140
 141         switch(cmd) {
 142                 case WDIOC_KEEPALIVE:
 143                         mtx1_wdt_reset();
 144                         break;
 145                 case WDIOC_GETSTATUS:
 146                 case WDIOC_GETBOOTSTATUS:
 147                         if ( copy_to_user(argp, &value, sizeof(int)) )
 148                                 return -EFAULT;
 149                         break;
 150                 case WDIOC_GETSUPPORT:
 151                         if ( copy_to_user(argp, &ident, sizeof(ident)) )
 152                                 return -EFAULT;
 153                         break;
 154                 case WDIOC_SETOPTIONS:
 155                         if ( copy_from_user(&value, argp, sizeof(int)) )
 156                                 return -EFAULT;
 157                         switch(value) {
 158                                 case WDIOS_ENABLECARD:
 159                                         mtx1_wdt_start();
 160                                         break;
 161                                 case WDIOS_DISABLECARD:
 162                                         return mtx1_wdt_stop();
 163                                 default:
 164                                         return -EINVAL;
 165                         }
 166                         break;
 167                 default:
 168                         return -ENOTTY;
 169         }
 170         return 0;
 171 }
 172
 173
 174 static ssize_t mtx1_wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 175 {
 176         if (!count)
 177                 return -EIO;
 178
 179         mtx1_wdt_reset();
 180         return count;
 181 }
 182
 183 static struct file_operations mtx1_wdt_fops = {
 184         .owner          = THIS_MODULE,
 185         .llseek         = no_llseek,
 186         .ioctl          = mtx1_wdt_ioctl,
 187         .open           = mtx1_wdt_open,
 188         .write          = mtx1_wdt_write,
 189         .release        = mtx1_wdt_release
 190 };
 191
 192
 193 static struct miscdevice mtx1_wdt_misc = {
 194         .minor  = WATCHDOG_MINOR,
 195         .name   = "watchdog",
 196         .fops   = &mtx1_wdt_fops
 197 };
 198
 199
 200 static int __init mtx1_wdt_init(void)
 201 {
 202         int ret;
 203
 204         if ((ret = misc_register(&mtx1_wdt_misc)) < 0) {
 205                 printk(KERN_ERR " mtx-1_wdt : failed to register\n");
 206                 return ret;
 207         }
 208
 209         init_completion(&mtx1_wdt_device.stop);
 210         mtx1_wdt_device.queue = 0;
 211
 212         clear_bit(0, &mtx1_wdt_device.inuse);
 213
 214         setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
 215
 216         mtx1_wdt_device.default_ticks = ticks;
 217
 218         mtx1_wdt_start();
 219
 220         printk(KERN_INFO "MTX-1 Watchdog driver\n");
 221
 222         return 0;
 223 }
 224
 225 static void __exit mtx1_wdt_exit(void)
 226 {
 227         if (mtx1_wdt_device.queue) {
 228                 mtx1_wdt_device.queue = 0;
 229                 wait_for_completion(&mtx1_wdt_device.stop);
 230         }
 231         misc_deregister(&mtx1_wdt_misc);
 232 }
 233
 234 module_init(mtx1_wdt_init);
 235 module_exit(mtx1_wdt_exit);
 236
 237 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
 238 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
 239 MODULE_LICENSE("GPL");