drivers/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 <linux/platform_device.h>
  49
  50 #include <asm/io.h>
  51 #include <asm/uaccess.h>
  52
  53 #include <asm/mach-au1x00/au1000.h>
  54 #include <asm/gpio.h>
  55
  56 #define MTX1_WDT_INTERVAL       (5 * HZ)
  57
  58 static int ticks = 100 * HZ;
  59
  60 static struct {
  61         struct completion stop;
  62         int running;
  63         struct timer_list timer;
  64         int queue;
  65         int default_ticks;
  66         unsigned long inuse;
  67         unsigned gpio;
  68 } mtx1_wdt_device;
  69
  70 static void mtx1_wdt_trigger(unsigned long unused)
  71 {
  72         u32 tmp;
  73
  74         if (mtx1_wdt_device.running)
  75                 ticks--;
  76         /*
  77          * toggle GPIO2_15
  78          */
  79         tmp = au_readl(GPIO2_DIR);
  80         tmp = (tmp & ~(1 << mtx1_wdt_device.gpio)) |
  81               ((~tmp) & (1 << mtx1_wdt_device.gpio));
  82         au_writel (tmp, GPIO2_DIR);
  83
  84         if (mtx1_wdt_device.queue && ticks)
  85                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
  86         else {
  87                 complete(&mtx1_wdt_device.stop);
  88         }
  89 }
  90
  91 static void mtx1_wdt_reset(void)
  92 {
  93         ticks = mtx1_wdt_device.default_ticks;
  94 }
  95
  96
  97 static void mtx1_wdt_start(void)
  98 {
  99         if (!mtx1_wdt_device.queue) {
 100                 mtx1_wdt_device.queue = 1;
 101                 gpio_set_value(mtx1_wdt_device.gpio, 1);
 102                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
 103         }
 104         mtx1_wdt_device.running++;
 105 }
 106
 107 static int mtx1_wdt_stop(void)
 108 {
 109         if (mtx1_wdt_device.queue) {
 110                 mtx1_wdt_device.queue = 0;
 111                 gpio_set_value(mtx1_wdt_device.gpio, 0);
 112         }
 113
 114         ticks = mtx1_wdt_device.default_ticks;
 115
 116         return 0;
 117 }
 118
 119 /* Filesystem functions */
 120
 121 static int mtx1_wdt_open(struct inode *inode, struct file *file)
 122 {
 123         if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
 124                 return -EBUSY;
 125
 126         return nonseekable_open(inode, file);
 127 }
 128
 129
 130 static int mtx1_wdt_release(struct inode *inode, struct file *file)
 131 {
 132         clear_bit(0, &mtx1_wdt_device.inuse);
 133         return 0;
 134 }
 135
 136 static int mtx1_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 137 {
 138         void __user *argp = (void __user *)arg;
 139         unsigned int value;
 140         static struct watchdog_info ident =
 141         {
 142                 .options = WDIOF_CARDRESET,
 143                 .identity = "MTX-1 WDT",
 144         };
 145
 146         switch(cmd) {
 147                 case WDIOC_KEEPALIVE:
 148                         mtx1_wdt_reset();
 149                         break;
 150                 case WDIOC_GETSTATUS:
 151                 case WDIOC_GETBOOTSTATUS:
 152                         if ( copy_to_user(argp, &value, sizeof(int)) )
 153                                 return -EFAULT;
 154                         break;
 155                 case WDIOC_GETSUPPORT:
 156                         if ( copy_to_user(argp, &ident, sizeof(ident)) )
 157                                 return -EFAULT;
 158                         break;
 159                 case WDIOC_SETOPTIONS:
 160                         if ( copy_from_user(&value, argp, sizeof(int)) )
 161                                 return -EFAULT;
 162                         switch(value) {
 163                                 case WDIOS_ENABLECARD:
 164                                         mtx1_wdt_start();
 165                                         break;
 166                                 case WDIOS_DISABLECARD:
 167                                         return mtx1_wdt_stop();
 168                                 default:
 169                                         return -EINVAL;
 170                         }
 171                         break;
 172                 default:
 173                         return -ENOTTY;
 174         }
 175         return 0;
 176 }
 177
 178
 179 static ssize_t mtx1_wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
 180 {
 181         if (!count)
 182                 return -EIO;
 183
 184         mtx1_wdt_reset();
 185         return count;
 186 }
 187
 188 static const struct file_operations mtx1_wdt_fops = {
 189         .owner          = THIS_MODULE,
 190         .llseek         = no_llseek,
 191         .ioctl          = mtx1_wdt_ioctl,
 192         .open           = mtx1_wdt_open,
 193         .write          = mtx1_wdt_write,
 194         .release        = mtx1_wdt_release
 195 };
 196
 197
 198 static struct miscdevice mtx1_wdt_misc = {
 199         .minor  = WATCHDOG_MINOR,
 200         .name   = "watchdog",
 201         .fops   = &mtx1_wdt_fops
 202 };
 203
 204
 205 static int mtx1_wdt_probe(struct platform_device *pdev)
 206 {
 207         int ret;
 208
 209         mtx1_wdt_device.gpio = pdev->resource[0].start;
 210
 211         if ((ret = misc_register(&mtx1_wdt_misc)) < 0) {
 212                 printk(KERN_ERR " mtx-1_wdt : failed to register\n");
 213                 return ret;
 214         }
 215
 216         init_completion(&mtx1_wdt_device.stop);
 217         mtx1_wdt_device.queue = 0;
 218
 219         clear_bit(0, &mtx1_wdt_device.inuse);
 220
 221         setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
 222
 223         mtx1_wdt_device.default_ticks = ticks;
 224
 225         mtx1_wdt_start();
 226
 227         printk(KERN_INFO "MTX-1 Watchdog driver\n");
 228
 229         return 0;
 230 }
 231
 232 static int mtx1_wdt_remove(struct platform_device *pdev)
 233 {
 234         if (mtx1_wdt_device.queue) {
 235                 mtx1_wdt_device.queue = 0;
 236                 wait_for_completion(&mtx1_wdt_device.stop);
 237         }
 238         misc_deregister(&mtx1_wdt_misc);
 239         return 0;
 240 }
 241
 242 static struct platform_driver mtx1_wdt = {
 243         .probe = mtx1_wdt_probe,
 244         .remove = mtx1_wdt_remove,
 245         .driver.name = "mtx1-wdt",
 246 };
 247
 248 static int __init mtx1_wdt_init(void)
 249 {
 250         return platform_driver_register(&mtx1_wdt);
 251 }
 252
 253 static void __exit mtx1_wdt_exit(void)
 254 {
 255         platform_driver_unregister(&mtx1_wdt);
 256 }
 257
 258 module_init(mtx1_wdt_init);
 259 module_exit(mtx1_wdt_exit);
 260
 261 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
 262 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
 263 MODULE_LICENSE("GPL");
 264 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);