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         spin_lock(&mtx1_wdt_device.lock);
  75         if (mtx1_wdt_device.running)
  76                 ticks--;
  77
  78         /* toggle wdt gpio */
  79         mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
  80         gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);
  81
  82         if (mtx1_wdt_device.queue && ticks)
  83                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
  84         else
  85                 complete(&mtx1_wdt_device.stop);
  86         spin_unlock(&mtx1_wdt_device.lock);
  87 }
  88
  89 static void mtx1_wdt_reset(void)
  90 {
  91         ticks = mtx1_wdt_device.default_ticks;
  92 }
  93
  94
  95 static void mtx1_wdt_start(void)
  96 {
  97         unsigned long flags;
  98
  99         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 100         if (!mtx1_wdt_device.queue) {
 101                 mtx1_wdt_device.queue = 1;
 102                 mtx1_wdt_device.gstate = 1;
 103                 gpio_set_value(mtx1_wdt_device.gpio, 1);
 104                 mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
 105         }
 106         mtx1_wdt_device.running++;
 107         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 108 }
 109
 110 static int mtx1_wdt_stop(void)
 111 {
 112         unsigned long flags;
 113
 114         spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 115         if (mtx1_wdt_device.queue) {
 116                 mtx1_wdt_device.queue = 0;
 117                 mtx1_wdt_device.gstate = 0;
 118                 gpio_set_value(mtx1_wdt_device.gpio, 0);
 119         }
 120         ticks = mtx1_wdt_device.default_ticks;
 121         spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
 122         return 0;
 123 }
 124
 125 /* Filesystem functions */
 126
 127 static int mtx1_wdt_open(struct inode *inode, struct file *file)
 128 {
 129         if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
 130                 return -EBUSY;
 131         return nonseekable_open(inode, file);
 132 }
 133
 134
 135 static int mtx1_wdt_release(struct inode *inode, struct file *file)
 136 {
 137         clear_bit(0, &mtx1_wdt_device.inuse);
 138         return 0;
 139 }
 140
 141 static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
 142                                                         unsigned long arg)
 143 {
 144         void __user *argp = (void __user *)arg;
 145         int __user *p = (int __user *)argp;
 146         unsigned int value;
 147         static const struct watchdog_info ident = {
 148                 .options = WDIOF_CARDRESET,
 149                 .identity = "MTX-1 WDT",
 150         };
 151
 152         switch (cmd) {
 153         case WDIOC_GETSUPPORT:
 154                 if (copy_to_user(argp, &ident, sizeof(ident)))
 155                         return -EFAULT;
 156                 break;
 157         case WDIOC_GETSTATUS:
 158         case WDIOC_GETBOOTSTATUS:
 159                 put_user(0, p);
 160                 break;
 161         case WDIOC_SETOPTIONS:
 162                 if (get_user(value, p))
 163                         return -EFAULT;
 164                 if (value & WDIOS_ENABLECARD)
 165                         mtx1_wdt_start();
 166                 else if (value & WDIOS_DISABLECARD)
 167                         mtx1_wdt_stop();
 168                 else
 169                         return -EINVAL;
 170                 return 0;
 171         case WDIOC_KEEPALIVE:
 172                 mtx1_wdt_reset();
 173                 break;
 174         default:
 175                 return -ENOTTY;
 176         }
 177         return 0;
 178 }
 179
 180
 181 static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
 182                                                 size_t count, loff_t *ppos)
 183 {
 184         if (!count)
 185                 return -EIO;
 186         mtx1_wdt_reset();
 187         return count;
 188 }
 189
 190 static const struct file_operations mtx1_wdt_fops = {
 191         .owner          = THIS_MODULE,
 192         .llseek         = no_llseek,
 193         .unlocked_ioctl = mtx1_wdt_ioctl,
 194         .open           = mtx1_wdt_open,
 195         .write          = mtx1_wdt_write,
 196         .release        = mtx1_wdt_release,
 197 };
 198
 199
 200 static struct miscdevice mtx1_wdt_misc = {
 201         .minor  = WATCHDOG_MINOR,
 202         .name   = "watchdog",
 203         .fops   = &mtx1_wdt_fops,
 204 };
 205
 206
 207 static int mtx1_wdt_probe(struct platform_device *pdev)
 208 {
 209         int ret;
 210
 211         mtx1_wdt_device.gpio = pdev->resource[0].start;
 212         ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio,
 213                                 GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
 214         if (ret < 0) {
 215                 dev_err(&pdev->dev, "failed to request gpio");
 216                 return ret;
 217         }
 218
 219         spin_lock_init(&mtx1_wdt_device.lock);
 220         init_completion(&mtx1_wdt_device.stop);
 221         mtx1_wdt_device.queue = 0;
 222         clear_bit(0, &mtx1_wdt_device.inuse);
 223         setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
 224         mtx1_wdt_device.default_ticks = ticks;
 225
 226         ret = misc_register(&mtx1_wdt_misc);
 227         if (ret < 0) {
 228                 dev_err(&pdev->dev, "failed to register\n");
 229                 return ret;
 230         }
 231         mtx1_wdt_start();
 232         dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
 233         return 0;
 234 }
 235
 236 static int mtx1_wdt_remove(struct platform_device *pdev)
 237 {
 238         /* FIXME: do we need to lock this test ? */
 239         if (mtx1_wdt_device.queue) {
 240                 mtx1_wdt_device.queue = 0;
 241                 wait_for_completion(&mtx1_wdt_device.stop);
 242         }
 243
 244         misc_deregister(&mtx1_wdt_misc);
 245         return 0;
 246 }
 247
 248 static struct platform_driver mtx1_wdt_driver = {
 249         .probe = mtx1_wdt_probe,
 250         .remove = mtx1_wdt_remove,
 251         .driver.name = "mtx1-wdt",
 252         .driver.owner = THIS_MODULE,
 253 };
 254
 255 module_platform_driver(mtx1_wdt_driver);
 256
 257 MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
 258 MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
 259 MODULE_LICENSE("GPL");
 260 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 261 MODULE_ALIAS("platform:mtx1-wdt");