package/avila-wdt/src/avila-wdt.c

   1 /*
   2  * avila-wdt.c
   3  * Copyright (C) 2009 Felix Fietkau <nbd@openwrt.org>
   4  *
   5  * based on:
   6  * drivers/char/watchdog/ixp4xx_wdt.c
   7  *
   8  * Watchdog driver for Intel IXP4xx network processors
   9  *
  10  * Author: Deepak Saxena <dsaxena@plexity.net>
  11  *
  12  * Copyright 2004 (c) MontaVista, Software, Inc.
  13  * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
  14  *
  15  * This file is licensed under  the terms of the GNU General Public
  16  * License version 2. This program is licensed "as is" without any
  17  * warranty of any kind, whether express or implied.
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/types.h>
  23 #include <linux/kernel.h>
  24 #include <linux/fs.h>
  25 #include <linux/miscdevice.h>
  26 #include <linux/watchdog.h>
  27 #include <linux/init.h>
  28 #include <linux/bitops.h>
  29 #include <linux/uaccess.h>
  30 #include <mach/hardware.h>
  31
  32 static int nowayout = WATCHDOG_NOWAYOUT;
  33 static int heartbeat = 20;      /* (secs) Default is 20 seconds */
  34 static unsigned long wdt_status;
  35 static atomic_t wdt_counter;
  36 struct timer_list wdt_timer;
  37
  38 #define WDT_IN_USE              0
  39 #define WDT_OK_TO_CLOSE         1
  40 #define WDT_RUNNING             2
  41
  42 static void wdt_refresh(unsigned long data)
  43 {
  44         if (test_bit(WDT_RUNNING, &wdt_status)) {
  45                 if (atomic_dec_and_test(&wdt_counter)) {
  46                         printk(KERN_WARNING "Avila watchdog expired, expect a reboot soon!\n");
  47                         clear_bit(WDT_RUNNING, &wdt_status);
  48                         return;
  49                 }
  50         }
  51
  52         /* strobe to the watchdog */
  53         gpio_line_set(14, IXP4XX_GPIO_HIGH);
  54         gpio_line_set(14, IXP4XX_GPIO_LOW);
  55
  56         mod_timer(&wdt_timer, jiffies + msecs_to_jiffies(500));
  57 }
  58
  59 static void wdt_enable(void)
  60 {
  61         atomic_set(&wdt_counter, heartbeat * 2);
  62
  63         /* Disable clock generator output on GPIO 14/15 */
  64         *IXP4XX_GPIO_GPCLKR &= ~(1 << 8);
  65
  66         /* activate GPIO 14 out */
  67         gpio_line_config(14, IXP4XX_GPIO_OUT);
  68         gpio_line_set(14, IXP4XX_GPIO_LOW);
  69
  70         if (!test_bit(WDT_RUNNING, &wdt_status))
  71                 wdt_refresh(0);
  72         set_bit(WDT_RUNNING, &wdt_status);
  73 }
  74
  75 static void wdt_disable(void)
  76 {
  77         /* Re-enable clock generator output on GPIO 14/15 */
  78         *IXP4XX_GPIO_GPCLKR |= (1 << 8);
  79 }
  80
  81 static int avila_wdt_open(struct inode *inode, struct file *file)
  82 {
  83         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
  84                 return -EBUSY;
  85
  86         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
  87         wdt_enable();
  88         return nonseekable_open(inode, file);
  89 }
  90
  91 static ssize_t
  92 avila_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
  93 {
  94         if (len) {
  95                 if (!nowayout) {
  96                         size_t i;
  97
  98                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
  99
 100                         for (i = 0; i != len; i++) {
 101                                 char c;
 102
 103                                 if (get_user(c, data + i))
 104                                         return -EFAULT;
 105                                 if (c == 'V')
 106                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 107                         }
 108                 }
 109                 wdt_enable();
 110         }
 111         return len;
 112 }
 113
 114 static struct watchdog_info ident = {
 115         .options        = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
 116                           WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 117         .identity       = "Avila Watchdog",
 118 };
 119
 120
 121 static long avila_wdt_ioctl(struct file *file, unsigned int cmd,
 122                                                         unsigned long arg)
 123 {
 124         int ret = -ENOTTY;
 125         int time;
 126
 127         switch (cmd) {
 128         case WDIOC_GETSUPPORT:
 129                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
 130                                    sizeof(ident)) ? -EFAULT : 0;
 131                 break;
 132
 133         case WDIOC_GETSTATUS:
 134                 ret = put_user(0, (int *)arg);
 135                 break;
 136
 137         case WDIOC_KEEPALIVE:
 138                 wdt_enable();
 139                 ret = 0;
 140                 break;
 141
 142         case WDIOC_SETTIMEOUT:
 143                 ret = get_user(time, (int *)arg);
 144                 if (ret)
 145                         break;
 146
 147                 if (time <= 0 || time > 60) {
 148                         ret = -EINVAL;
 149                         break;
 150                 }
 151
 152                 heartbeat = time;
 153                 wdt_enable();
 154                 /* Fall through */
 155
 156         case WDIOC_GETTIMEOUT:
 157                 ret = put_user(heartbeat, (int *)arg);
 158                 break;
 159         }
 160         return ret;
 161 }
 162
 163 static int avila_wdt_release(struct inode *inode, struct file *file)
 164 {
 165         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 166                 wdt_disable();
 167         else
 168                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
 169                                         "timer will not stop\n");
 170         clear_bit(WDT_IN_USE, &wdt_status);
 171         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 172
 173         return 0;
 174 }
 175
 176
 177 static const struct file_operations avila_wdt_fops = {
 178         .owner          = THIS_MODULE,
 179         .llseek         = no_llseek,
 180         .write          = avila_wdt_write,
 181         .unlocked_ioctl = avila_wdt_ioctl,
 182         .open           = avila_wdt_open,
 183         .release        = avila_wdt_release,
 184 };
 185
 186 static struct miscdevice avila_wdt_miscdev = {
 187         .minor          = WATCHDOG_MINOR + 1,
 188         .name           = "avila_watchdog",
 189         .fops           = &avila_wdt_fops,
 190 };
 191
 192 static int __init avila_wdt_init(void)
 193 {
 194         int ret;
 195
 196         init_timer(&wdt_timer);
 197         wdt_timer.expires = 0;
 198         wdt_timer.data = 0;
 199         wdt_timer.function = wdt_refresh;
 200         ret = misc_register(&avila_wdt_miscdev);
 201         if (ret == 0)
 202                 printk(KERN_INFO "Avila Watchdog Timer: heartbeat %d sec\n",
 203                         heartbeat);
 204         return ret;
 205 }
 206
 207 static void __exit avila_wdt_exit(void)
 208 {
 209         misc_deregister(&avila_wdt_miscdev);
 210         del_timer(&wdt_timer);
 211         wdt_disable();
 212 }
 213
 214
 215 module_init(avila_wdt_init);
 216 module_exit(avila_wdt_exit);
 217
 218 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 219 MODULE_DESCRIPTION("Gateworks Avila Hardware Watchdog");
 220
 221 module_param(heartbeat, int, 0);
 222 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 20s)");
 223
 224 module_param(nowayout, int, 0);
 225 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
 226
 227 MODULE_LICENSE("GPL");
 228 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 229