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 } mtx1_wdt_device;
  70
  71 static void mtx1_wdt_trigger(unsigned long unused)
  72 {
  73         u32 tmp;
  74
  75         spin_lock(&mtx1_wdt_device.lock);
  76         if (mtx1_wdt_device.running)
  77                 ticks--;
  78         /*
  79          * toggle GPIO2_15
  80          */
  81         tmp = au_readl(GPIO2_DIR);
  82         tmp = (tmp & ~(1 << mtx1_wdt_device.gpio)) |
  83               ((~tmp) & (1 << mtx1_wdt_device.gpio));
  84         au_writel(tmp, GPIO2_DIR);
  85
  86         if (mtx1_wdt_device.queue && ticks)
  87                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
  88         else
  89                 complete(&mtx1_wdt_device.stop);
  90         spin_unlock(&mtx1_wdt_device.lock);
  91 }
  92
  93 static void mtx1_wdt_reset(void)
  94 {
  95         ticks = mtx1_wdt_device.default_ticks;
  96 }
  97
  98
  99 static void mtx1_wdt_start(void)
 100 {
 101         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 102         if (!mtx1_wdt_device.queue) {
 103                 mtx1_wdt_device.queue = 1;
 104                 gpio_set_value(mtx1_wdt_device.gpio, 1);
 105                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
 106         }
 107         mtx1_wdt_device.running++;
 108         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 109 }
 110
 111 static int mtx1_wdt_stop(void)
 112 {
 113         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 114         if (mtx1_wdt_device.queue) {
 115                 mtx1_wdt_device.queue = 0;
 116                 gpio_set_value(mtx1_wdt_device.gpio, 0);
 117         }
 118         ticks = mtx1_wdt_device.default_ticks;
 119         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 120         return 0;
 121 }
 122
 123 /* Filesystem functions */
 124
 125 static int mtx1_wdt_open(struct inode *inode, struct file *file)
 126 {
 127         if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
 128                 return -EBUSY;
 129         return nonseekable_open(inode, file);
 130 }
 131
 132
 133 static int mtx1_wdt_release(struct inode *inode, struct file *file)
 134 {
 135         clear_bit(0, &mtx1_wdt_device.inuse);
 136         return 0;
 137 }
 138
 139 static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
 140                                                         unsigned long arg)
 141 {
 142         void __user *argp = (void __user *)arg;
 143         int __user *p = (int __user *)argp;
 144         unsigned int value;
 145         static const struct watchdog_info ident = {
 146                 .options = WDIOF_CARDRESET,
 147                 .identity = "MTX-1 WDT",
 148         };
 149
 150         switch (cmd) {
 151         case WDIOC_GETSUPPORT:
 152                 if (copy_to_user(argp, &ident, sizeof(ident)))
 153                         return -EFAULT;
 154                 break;
 155         case WDIOC_GETSTATUS:
 156         case WDIOC_GETBOOTSTATUS:
 157                 put_user(0, p);
 158                 break;
 159         case WDIOC_SETOPTIONS:
 160                 if (get_user(value, p))
 161                         return -EFAULT;
 162                 if (value & WDIOS_ENABLECARD)
 163                         mtx1_wdt_start();
 164                 else if (value & WDIOS_DISABLECARD)
 165                         mtx1_wdt_stop();
 166                 else
 167                         return -EINVAL;
 168                 return 0;
 169         case WDIOC_KEEPALIVE:
 170                 mtx1_wdt_reset();
 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,
 180                                                 size_t count, loff_t *ppos)
 181 {
 182         if (!count)
 183                 return -EIO;
 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         .unlocked_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         spin_lock_init(&mtx1_wdt_device.lock);
 212         init_completion(&mtx1_wdt_device.stop);
 213         mtx1_wdt_device.queue = 0;
 214         clear_bit(0, &mtx1_wdt_device.inuse);
 215         setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
 216         mtx1_wdt_device.default_ticks = ticks;
 217
 218         ret = misc_register(&mtx1_wdt_misc);
 219         if (ret < 0) {
 220                 printk(KERN_ERR " mtx-1_wdt : failed to register\n");
 221                 return ret;
 222         }
 223         mtx1_wdt_start();
 224         printk(KERN_INFO "MTX-1 Watchdog driver\n");
 225         return 0;
 226 }
 227
 228 static int mtx1_wdt_remove(struct platform_device *pdev)
 229 {
 230         /* FIXME: do we need to lock this test ? */
 231         if (mtx1_wdt_device.queue) {
 232                 mtx1_wdt_device.queue = 0;
 233                 wait_for_completion(&mtx1_wdt_device.stop);
 234         }
 235         misc_deregister(&mtx1_wdt_misc);
 236         return 0;
 237 }
 238
 239 static struct platform_driver mtx1_wdt = {
 240         .probe = mtx1_wdt_probe,
 241         .remove = mtx1_wdt_remove,
 242         .driver.name = "mtx1-wdt",
 243         .driver.owner = THIS_MODULE,
 244 };
 245
 246 static int __init mtx1_wdt_init(void)
 247 {
 248         return platform_driver_register(&mtx1_wdt);
 249 }
 250
 251 static void __exit mtx1_wdt_exit(void)
 252 {
 253         platform_driver_unregister(&mtx1_wdt);
 254 }
 255
 256 module_init(mtx1_wdt_init);
 257 module_exit(mtx1_wdt_exit);
 258
 259 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
 260 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
 261 MODULE_LICENSE("GPL");
 262 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 263 MODULE_ALIAS("platform:mtx1-wdt");