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         unsigned long flags;
 102
 103         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 104         if (!mtx1_wdt_device.queue) {
 105                 mtx1_wdt_device.queue = 1;
 106                 gpio_set_value(mtx1_wdt_device.gpio, 1);
 107                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
 108         }
 109         mtx1_wdt_device.running++;
 110         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 111 }
 112
 113 static int mtx1_wdt_stop(void)
 114 {
 115         unsigned long flags;
 116
 117         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 118         if (mtx1_wdt_device.queue) {
 119                 mtx1_wdt_device.queue = 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 mtx1_wdt_probe(struct platform_device *pdev)
 210 {
 211         int ret;
 212
 213         mtx1_wdt_device.gpio = pdev->resource[0].start;
 214
 215         spin_lock_init(&mtx1_wdt_device.lock);
 216         init_completion(&mtx1_wdt_device.stop);
 217         mtx1_wdt_device.queue = 0;
 218         clear_bit(0, &mtx1_wdt_device.inuse);
 219         setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
 220         mtx1_wdt_device.default_ticks = ticks;
 221
 222         ret = misc_register(&mtx1_wdt_misc);
 223         if (ret < 0) {
 224                 printk(KERN_ERR " mtx-1_wdt : failed to register\n");
 225                 return ret;
 226         }
 227         mtx1_wdt_start();
 228         printk(KERN_INFO "MTX-1 Watchdog driver\n");
 229         return 0;
 230 }
 231
 232 static int mtx1_wdt_remove(struct platform_device *pdev)
 233 {
 234         /* FIXME: do we need to lock this test ? */
 235         if (mtx1_wdt_device.queue) {
 236                 mtx1_wdt_device.queue = 0;
 237                 wait_for_completion(&mtx1_wdt_device.stop);
 238         }
 239         misc_deregister(&mtx1_wdt_misc);
 240         return 0;
 241 }
 242
 243 static struct platform_driver mtx1_wdt = {
 244         .probe = mtx1_wdt_probe,
 245         .remove = mtx1_wdt_remove,
 246         .driver.name = "mtx1-wdt",
 247         .driver.owner = THIS_MODULE,
 248 };
 249
 250 static int __init mtx1_wdt_init(void)
 251 {
 252         return platform_driver_register(&mtx1_wdt);
 253 }
 254
 255 static void __exit mtx1_wdt_exit(void)
 256 {
 257         platform_driver_unregister(&mtx1_wdt);
 258 }
 259
 260 module_init(mtx1_wdt_init);
 261 module_exit(mtx1_wdt_exit);
 262
 263 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
 264 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
 265 MODULE_LICENSE("GPL");
 266 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 267 MODULE_ALIAS("platform:mtx1-wdt");