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         unsigned 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         gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);
  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         spin_unlock(&mtx1_wdt_device.lock);
  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         unsigned long flags;
 100
 101         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 102         if (!mtx1_wdt_device.queue) {
 103                 mtx1_wdt_device.queue = 1;
 104                 mtx1_wdt_device.gstate = 1;
 105                 gpio_set_value(mtx1_wdt_device.gpio, 1);
 106                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
 107         }
 108         mtx1_wdt_device.running++;
 109         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 110 }
 111
 112 static int mtx1_wdt_stop(void)
 113 {
 114         unsigned long flags;
 115
 116         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 117         if (mtx1_wdt_device.queue) {
 118                 mtx1_wdt_device.queue = 0;
 119                 mtx1_wdt_device.gstate = 0;
 120                 gpio_set_value(mtx1_wdt_device.gpio, 0);
 121         }
 122         ticks = mtx1_wdt_device.default_ticks;
 123         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 124         return 0;
 125 }
 126
 127 /* Filesystem functions */
 128
 129 static int mtx1_wdt_open(struct inode *inode, struct file *file)
 130 {
 131         if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
 132                 return -EBUSY;
 133         return nonseekable_open(inode, file);
 134 }
 135
 136
 137 static int mtx1_wdt_release(struct inode *inode, struct file *file)
 138 {
 139         clear_bit(0, &mtx1_wdt_device.inuse);
 140         return 0;
 141 }
 142
 143 static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
 144                                                         unsigned long arg)
 145 {
 146         void __user *argp = (void __user *)arg;
 147         int __user *p = (int __user *)argp;
 148         unsigned int value;
 149         static const struct watchdog_info ident = {
 150                 .options = WDIOF_CARDRESET,
 151                 .identity = "MTX-1 WDT",
 152         };
 153
 154         switch (cmd) {
 155         case WDIOC_GETSUPPORT:
 156                 if (copy_to_user(argp, &ident, sizeof(ident)))
 157                         return -EFAULT;
 158                 break;
 159         case WDIOC_GETSTATUS:
 160         case WDIOC_GETBOOTSTATUS:
 161                 put_user(0, p);
 162                 break;
 163         case WDIOC_SETOPTIONS:
 164                 if (get_user(value, p))
 165                         return -EFAULT;
 166                 if (value & WDIOS_ENABLECARD)
 167                         mtx1_wdt_start();
 168                 else if (value & WDIOS_DISABLECARD)
 169                         mtx1_wdt_stop();
 170                 else
 171                         return -EINVAL;
 172                 return 0;
 173         case WDIOC_KEEPALIVE:
 174                 mtx1_wdt_reset();
 175                 break;
 176         default:
 177                 return -ENOTTY;
 178         }
 179         return 0;
 180 }
 181
 182
 183 static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
 184                                                 size_t count, loff_t *ppos)
 185 {
 186         if (!count)
 187                 return -EIO;
 188         mtx1_wdt_reset();
 189         return count;
 190 }
 191
 192 static const struct file_operations mtx1_wdt_fops = {
 193         .owner          = THIS_MODULE,
 194         .llseek         = no_llseek,
 195         .unlocked_ioctl = mtx1_wdt_ioctl,
 196         .open           = mtx1_wdt_open,
 197         .write          = mtx1_wdt_write,
 198         .release        = mtx1_wdt_release,
 199 };
 200
 201
 202 static struct miscdevice mtx1_wdt_misc = {
 203         .minor  = WATCHDOG_MINOR,
 204         .name   = "watchdog",
 205         .fops   = &mtx1_wdt_fops,
 206 };
 207
 208
 209 static int __devinit mtx1_wdt_probe(struct platform_device *pdev)
 210 {
 211         int ret;
 212
 213         mtx1_wdt_device.gpio = pdev->resource[0].start;
 214         ret = gpio_request_one(mtx1_wdt_device.gpio,
 215                                 GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
 216         if (ret < 0) {
 217                 dev_err(&pdev->dev, "failed to request gpio");
 218                 return ret;
 219         }
 220
 221         spin_lock_init(&mtx1_wdt_device.lock);
 222         init_completion(&mtx1_wdt_device.stop);
 223         mtx1_wdt_device.queue = 0;
 224         clear_bit(0, &mtx1_wdt_device.inuse);
 225         setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
 226         mtx1_wdt_device.default_ticks = ticks;
 227
 228         ret = misc_register(&mtx1_wdt_misc);
 229         if (ret < 0) {
 230                 printk(KERN_ERR " mtx-1_wdt : failed to register\n");
 231                 return ret;
 232         }
 233         mtx1_wdt_start();
 234         printk(KERN_INFO "MTX-1 Watchdog driver\n");
 235         return 0;
 236 }
 237
 238 static int __devexit mtx1_wdt_remove(struct platform_device *pdev)
 239 {
 240         /* FIXME: do we need to lock this test ? */
 241         if (mtx1_wdt_device.queue) {
 242                 mtx1_wdt_device.queue = 0;
 243                 wait_for_completion(&mtx1_wdt_device.stop);
 244         }
 245
 246         gpio_free(mtx1_wdt_device.gpio);
 247         misc_deregister(&mtx1_wdt_misc);
 248         return 0;
 249 }
 250
 251 static struct platform_driver mtx1_wdt = {
 252         .probe = mtx1_wdt_probe,
 253         .remove = __devexit_p(mtx1_wdt_remove),
 254         .driver.name = "mtx1-wdt",
 255         .driver.owner = THIS_MODULE,
 256 };
 257
 258 static int __init mtx1_wdt_init(void)
 259 {
 260         return platform_driver_register(&mtx1_wdt);
 261 }
 262
 263 static void __exit mtx1_wdt_exit(void)
 264 {
 265         platform_driver_unregister(&mtx1_wdt);
 266 }
 267
 268 module_init(mtx1_wdt_init);
 269 module_exit(mtx1_wdt_exit);
 270
 271 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
 272 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
 273 MODULE_LICENSE("GPL");
 274 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 275 MODULE_ALIAS("platform:mtx1-wdt");