release/src-rt-6.x/linux/linux-2.6/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                         if ( copy_to_user(argp, &value, sizeof(int)) )
 147                                 return -EFAULT;
 148                         break;
 149                 case WDIOC_GETSUPPORT:
 150                         if ( copy_to_user(argp, &ident, sizeof(ident)) )
 151                                 return -EFAULT;
 152                         break;
 153                 case WDIOC_SETOPTIONS:
 154                         if ( copy_from_user(&value, argp, sizeof(int)) )
 155                                 return -EFAULT;
 156                         switch(value) {
 157                                 case WDIOS_ENABLECARD:
 158                                         mtx1_wdt_start();
 159                                         break;
 160                                 case WDIOS_DISABLECARD:
 161                                         return mtx1_wdt_stop();
 162                                 default:
 163                                         return -EINVAL;
 164                         }
 165                         break;
 166                 default:
 167                         return -ENOTTY;
 168         }
 169         return 0;
 170 }
 171
 172
 173 static ssize_t mtx1_wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 174 {
 175         if (!count)
 176                 return -EIO;
 177
 178         mtx1_wdt_reset();
 179         return count;
 180 }
 181
 182 static struct file_operations mtx1_wdt_fops = {
 183         .owner          = THIS_MODULE,
 184         .llseek         = no_llseek,
 185         .ioctl          = mtx1_wdt_ioctl,
 186         .open           = mtx1_wdt_open,
 187         .write          = mtx1_wdt_write,
 188         .release        = mtx1_wdt_release
 189 };
 190
 191
 192 static struct miscdevice mtx1_wdt_misc = {
 193         .minor  = WATCHDOG_MINOR,
 194         .name   = "watchdog",
 195         .fops   = &mtx1_wdt_fops
 196 };
 197
 198
 199 static int __init mtx1_wdt_init(void)
 200 {
 201         int ret;
 202
 203         if ((ret = misc_register(&mtx1_wdt_misc)) < 0) {
 204                 printk(KERN_ERR " mtx-1_wdt : failed to register\n");
 205                 return ret;
 206         }
 207
 208         init_completion(&mtx1_wdt_device.stop);
 209         mtx1_wdt_device.queue = 0;
 210
 211         clear_bit(0, &mtx1_wdt_device.inuse);
 212
 213         setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
 214
 215         mtx1_wdt_device.default_ticks = ticks;
 216
 217         mtx1_wdt_start();
 218
 219         printk(KERN_INFO "MTX-1 Watchdog driver\n");
 220
 221         return 0;
 222 }
 223
 224 static void __exit mtx1_wdt_exit(void)
 225 {
 226         if (mtx1_wdt_device.queue) {
 227                 mtx1_wdt_device.queue = 0;
 228                 wait_for_completion(&mtx1_wdt_device.stop);
 229         }
 230         misc_deregister(&mtx1_wdt_misc);
 231 }
 232
 233 module_init(mtx1_wdt_init);
 234 module_exit(mtx1_wdt_exit);
 235
 236 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
 237 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
 238 MODULE_LICENSE("GPL");