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/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 #include <linux/io.h>
  50 #include <linux/uaccess.h>
  51 #include <linux/gpio.h>
  52
  53 #include <asm/mach-au1x00/au1000.h>
  54
  55 #define MTX1_WDT_INTERVAL       (5 * HZ)
  56
  57 static int ticks = 100 * HZ;
  58
  59 static struct {
  60         struct completion stop;
  61         spinlock_t lock;
  62         int running;
  63         struct timer_list timer;
  64         int queue;
  65         int default_ticks;
  66         unsigned long inuse;
  67         unsigned gpio;
  68         unsigned int gstate;
  69 } mtx1_wdt_device;
  70
  71 static void mtx1_wdt_trigger(struct timer_list *unused)
  72 {
  73         spin_lock(&mtx1_wdt_device.lock);
  74         if (mtx1_wdt_device.running)
  75                 ticks--;
  76
  77         /* toggle wdt gpio */
  78         mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
  79         gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);
  80
  81         if (mtx1_wdt_device.queue && ticks)
  82                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
  83         else
  84                 complete(&mtx1_wdt_device.stop);
  85         spin_unlock(&mtx1_wdt_device.lock);
  86 }
  87
  88 static void mtx1_wdt_reset(void)
  89 {
  90         ticks = mtx1_wdt_device.default_ticks;
  91 }
  92
  93
  94 static void mtx1_wdt_start(void)
  95 {
  96         unsigned long flags;
  97
  98         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
  99         if (!mtx1_wdt_device.queue) {
 100                 mtx1_wdt_device.queue = 1;
 101                 mtx1_wdt_device.gstate = 1;
 102                 gpio_set_value(mtx1_wdt_device.gpio, 1);
 103                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
 104         }
 105         mtx1_wdt_device.running++;
 106         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 107 }
 108
 109 static int mtx1_wdt_stop(void)
 110 {
 111         unsigned long flags;
 112
 113         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 114         if (mtx1_wdt_device.queue) {
 115                 mtx1_wdt_device.queue = 0;
 116                 mtx1_wdt_device.gstate = 0;
 117                 gpio_set_value(mtx1_wdt_device.gpio, 0);
 118         }
 119         ticks = mtx1_wdt_device.default_ticks;
 120         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 121         return 0;
 122 }
 123
 124 /* Filesystem functions */
 125
 126 static int mtx1_wdt_open(struct inode *inode, struct file *file)
 127 {
 128         if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
 129                 return -EBUSY;
 130         return nonseekable_open(inode, file);
 131 }
 132
 133
 134 static int mtx1_wdt_release(struct inode *inode, struct file *file)
 135 {
 136         clear_bit(0, &mtx1_wdt_device.inuse);
 137         return 0;
 138 }
 139
 140 static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
 141                                                         unsigned long arg)
 142 {
 143         void __user *argp = (void __user *)arg;
 144         int __user *p = (int __user *)argp;
 145         unsigned int value;
 146         static const struct watchdog_info ident = {
 147                 .options = WDIOF_CARDRESET,
 148                 .identity = "MTX-1 WDT",
 149         };
 150
 151         switch (cmd) {
 152         case WDIOC_GETSUPPORT:
 153                 if (copy_to_user(argp, &ident, sizeof(ident)))
 154                         return -EFAULT;
 155                 break;
 156         case WDIOC_GETSTATUS:
 157         case WDIOC_GETBOOTSTATUS:
 158                 put_user(0, p);
 159                 break;
 160         case WDIOC_SETOPTIONS:
 161                 if (get_user(value, p))
 162                         return -EFAULT;
 163                 if (value & WDIOS_ENABLECARD)
 164                         mtx1_wdt_start();
 165                 else if (value & WDIOS_DISABLECARD)
 166                         mtx1_wdt_stop();
 167                 else
 168                         return -EINVAL;
 169                 return 0;
 170         case WDIOC_KEEPALIVE:
 171                 mtx1_wdt_reset();
 172                 break;
 173         default:
 174                 return -ENOTTY;
 175         }
 176         return 0;
 177 }
 178
 179
 180 static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
 181                                                 size_t count, loff_t *ppos)
 182 {
 183         if (!count)
 184                 return -EIO;
 185         mtx1_wdt_reset();
 186         return count;
 187 }
 188
 189 static const struct file_operations mtx1_wdt_fops = {
 190         .owner          = THIS_MODULE,
 191         .llseek         = no_llseek,
 192         .unlocked_ioctl = mtx1_wdt_ioctl,
 193         .open           = mtx1_wdt_open,
 194         .write          = mtx1_wdt_write,
 195         .release        = mtx1_wdt_release,
 196 };
 197
 198
 199 static struct miscdevice mtx1_wdt_misc = {
 200         .minor  = WATCHDOG_MINOR,
 201         .name   = "watchdog",
 202         .fops   = &mtx1_wdt_fops,
 203 };
 204
 205
 206 static int mtx1_wdt_probe(struct platform_device *pdev)
 207 {
 208         int ret;
 209
 210         mtx1_wdt_device.gpio = pdev->resource[0].start;
 211         ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio,
 212                                 GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
 213         if (ret < 0) {
 214                 dev_err(&pdev->dev, "failed to request gpio");
 215                 return ret;
 216         }
 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         timer_setup(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0);
 223         mtx1_wdt_device.default_ticks = ticks;
 224
 225         ret = misc_register(&mtx1_wdt_misc);
 226         if (ret < 0) {
 227                 dev_err(&pdev->dev, "failed to register\n");
 228                 return ret;
 229         }
 230         mtx1_wdt_start();
 231         dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
 232         return 0;
 233 }
 234
 235 static int 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
 243         misc_deregister(&mtx1_wdt_misc);
 244         return 0;
 245 }
 246
 247 static struct platform_driver mtx1_wdt_driver = {
 248         .probe = mtx1_wdt_probe,
 249         .remove = mtx1_wdt_remove,
 250         .driver.name = "mtx1-wdt",
 251         .driver.owner = THIS_MODULE,
 252 };
 253
 254 module_platform_driver(mtx1_wdt_driver);
 255
 256 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
 257 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
 258 MODULE_LICENSE("GPL");
 259 MODULE_ALIAS("platform:mtx1-wdt");