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>,
   5  *                                                      All Rights Reserved.
   6  *                              http://www.4g-systems.biz
   7  *
   8  *      (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org>
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  *
  15  *      Neither Michael Stickel nor 4G Systems admit liability nor provide
  16  *      warranty for any of this software. This material is provided
  17  *      "AS-IS" and at no charge.
  18  *
  19  *      (c) Copyright 2005    4G Systems <info@4g-systems.biz>
  20  *
  21  *      Release 0.01.
  22  *      Author: Michael Stickel  michael.stickel@4g-systems.biz
  23  *
  24  *      Release 0.02.
  25  *      Author: Florian Fainelli florian@openwrt.org
  26  *              use the Linux watchdog/timer APIs
  27  *
  28  *      The Watchdog is configured to reset the MTX-1
  29  *      if it is not triggered for 100 seconds.
  30  *      It should not be triggered more often than 1.6 seconds.
  31  *
  32  *      A timer triggers the watchdog every 5 seconds, until
  33  *      it is opened for the first time. After the first open
  34  *      it MUST be triggered every 2..95 seconds.
  35  */
  36
  37 #include <linux/module.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/types.h>
  40 #include <linux/errno.h>
  41 #include <linux/miscdevice.h>
  42 #include <linux/fs.h>
  43 #include <linux/init.h>
  44 #include <linux/ioport.h>
  45 #include <linux/timer.h>
  46 #include <linux/completion.h>
  47 #include <linux/jiffies.h>
  48 #include <linux/watchdog.h>
  49 #include <linux/platform_device.h>
  50 #include <linux/io.h>
  51 #include <linux/uaccess.h>
  52 #include <linux/gpio.h>
  53
  54 #include <asm/mach-au1x00/au1000.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         spinlock_t lock;
  63         int running;
  64         struct timer_list timer;
  65         int queue;
  66         int default_ticks;
  67         unsigned long inuse;
  68         unsigned gpio;
  69         int gstate;
  70 } mtx1_wdt_device;
  71
  72 static void mtx1_wdt_trigger(unsigned long unused)
  73 {
  74         u32 tmp;
  75
  76         spin_lock(&mtx1_wdt_device.lock);
  77         if (mtx1_wdt_device.running)
  78                 ticks--;
  79
  80         /* toggle wdt gpio */
  81         mtx1_wdt_device.gstate = ~mtx1_wdt_device.gstate;
  82         if (mtx1_wdt_device.gstate)
  83                 gpio_direction_output(mtx1_wdt_device.gpio, 1);
  84         else
  85                 gpio_direction_input(mtx1_wdt_device.gpio);
  86
  87         if (mtx1_wdt_device.queue && ticks)
  88                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
  89         else
  90                 complete(&mtx1_wdt_device.stop);
  91         spin_unlock(&mtx1_wdt_device.lock);
  92 }
  93
  94 static void mtx1_wdt_reset(void)
  95 {
  96         ticks = mtx1_wdt_device.default_ticks;
  97 }
  98
  99
 100 static void mtx1_wdt_start(void)
 101 {
 102         unsigned long flags;
 103
 104         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 105         if (!mtx1_wdt_device.queue) {
 106                 mtx1_wdt_device.queue = 1;
 107                 mtx1_wdt_device.gstate = 1;
 108                 gpio_direction_output(mtx1_wdt_device.gpio, 1);
 109                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
 110         }
 111         mtx1_wdt_device.running++;
 112         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 113 }
 114
 115 static int mtx1_wdt_stop(void)
 116 {
 117         unsigned long flags;
 118
 119         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 120         if (mtx1_wdt_device.queue) {
 121                 mtx1_wdt_device.queue = 0;
 122                 mtx1_wdt_device.gstate = 0;
 123                 gpio_direction_output(mtx1_wdt_device.gpio, 0);
 124         }
 125         ticks = mtx1_wdt_device.default_ticks;
 126         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 127         return 0;
 128 }
 129
 130 /* Filesystem functions */
 131
 132 static int mtx1_wdt_open(struct inode *inode, struct file *file)
 133 {
 134         if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
 135                 return -EBUSY;
 136         return nonseekable_open(inode, file);
 137 }
 138
 139
 140 static int mtx1_wdt_release(struct inode *inode, struct file *file)
 141 {
 142         clear_bit(0, &mtx1_wdt_device.inuse);
 143         return 0;
 144 }
 145
 146 static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
 147                                                         unsigned long arg)
 148 {
 149         void __user *argp = (void __user *)arg;
 150         int __user *p = (int __user *)argp;
 151         unsigned int value;
 152         static const struct watchdog_info ident = {
 153                 .options = WDIOF_CARDRESET,
 154                 .identity = "MTX-1 WDT",
 155         };
 156
 157         switch (cmd) {
 158         case WDIOC_GETSUPPORT:
 159                 if (copy_to_user(argp, &ident, sizeof(ident)))
 160                         return -EFAULT;
 161                 break;
 162         case WDIOC_GETSTATUS:
 163         case WDIOC_GETBOOTSTATUS:
 164                 put_user(0, p);
 165                 break;
 166         case WDIOC_SETOPTIONS:
 167                 if (get_user(value, p))
 168                         return -EFAULT;
 169                 if (value & WDIOS_ENABLECARD)
 170                         mtx1_wdt_start();
 171                 else if (value & WDIOS_DISABLECARD)
 172                         mtx1_wdt_stop();
 173                 else
 174                         return -EINVAL;
 175                 return 0;
 176         case WDIOC_KEEPALIVE:
 177                 mtx1_wdt_reset();
 178                 break;
 179         default:
 180                 return -ENOTTY;
 181         }
 182         return 0;
 183 }
 184
 185
 186 static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
 187                                                 size_t count, loff_t *ppos)
 188 {
 189         if (!count)
 190                 return -EIO;
 191         mtx1_wdt_reset();
 192         return count;
 193 }
 194
 195 static const struct file_operations mtx1_wdt_fops = {
 196         .owner          = THIS_MODULE,
 197         .llseek         = no_llseek,
 198         .unlocked_ioctl = mtx1_wdt_ioctl,
 199         .open           = mtx1_wdt_open,
 200         .write          = mtx1_wdt_write,
 201         .release        = mtx1_wdt_release,
 202 };
 203
 204
 205 static struct miscdevice mtx1_wdt_misc = {
 206         .minor  = WATCHDOG_MINOR,
 207         .name   = "watchdog",
 208         .fops   = &mtx1_wdt_fops,
 209 };
 210
 211
 212 static int __devinit mtx1_wdt_probe(struct platform_device *pdev)
 213 {
 214         int ret;
 215
 216         mtx1_wdt_device.gpio = pdev->resource[0].start;
 217
 218         spin_lock_init(&mtx1_wdt_device.lock);
 219         init_completion(&mtx1_wdt_device.stop);
 220         mtx1_wdt_device.queue = 0;
 221         clear_bit(0, &mtx1_wdt_device.inuse);
 222         setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
 223         mtx1_wdt_device.default_ticks = ticks;
 224
 225         ret = misc_register(&mtx1_wdt_misc);
 226         if (ret < 0) {
 227                 printk(KERN_ERR " mtx-1_wdt : failed to register\n");
 228                 return ret;
 229         }
 230         mtx1_wdt_start();
 231         printk(KERN_INFO "MTX-1 Watchdog driver\n");
 232         return 0;
 233 }
 234
 235 static int __devexit mtx1_wdt_remove(struct platform_device *pdev)
 236 {
 237         /* FIXME: do we need to lock this test ? */
 238         if (mtx1_wdt_device.queue) {
 239                 mtx1_wdt_device.queue = 0;
 240                 wait_for_completion(&mtx1_wdt_device.stop);
 241         }
 242         misc_deregister(&mtx1_wdt_misc);
 243         return 0;
 244 }
 245
 246 static struct platform_driver mtx1_wdt = {
 247         .probe = mtx1_wdt_probe,
 248         .remove = __devexit_p(mtx1_wdt_remove),
 249         .driver.name = "mtx1-wdt",
 250         .driver.owner = THIS_MODULE,
 251 };
 252
 253 static int __init mtx1_wdt_init(void)
 254 {
 255         return platform_driver_register(&mtx1_wdt);
 256 }
 257
 258 static void __exit mtx1_wdt_exit(void)
 259 {
 260         platform_driver_unregister(&mtx1_wdt);
 261 }
 262
 263 module_init(mtx1_wdt_init);
 264 module_exit(mtx1_wdt_exit);
 265
 266 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
 267 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
 268 MODULE_LICENSE("GPL");
 269 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 270 MODULE_ALIAS("platform:mtx1-wdt");