package/kernel/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/jiffies.h>
  25 #include <linux/timer.h>
  26 #include <linux/fs.h>
  27 #include <linux/miscdevice.h>
  28 #include <linux/watchdog.h>
  29 #include <linux/init.h>
  30 #include <linux/bitops.h>
  31 #include <linux/uaccess.h>
  32 #include <mach/hardware.h>
  33
  34 static int nowayout = WATCHDOG_NOWAYOUT;
  35 static int heartbeat = 20;      /* (secs) Default is 20 seconds */
  36 static unsigned long wdt_status;
  37 static atomic_t wdt_counter;
  38 struct timer_list wdt_timer;
  39
  40 #define WDT_IN_USE              0
  41 #define WDT_OK_TO_CLOSE         1
  42 #define WDT_RUNNING             2
  43
  44 static void wdt_refresh(unsigned long data)
  45 {
  46         if (test_bit(WDT_RUNNING, &wdt_status)) {
  47                 if (atomic_dec_and_test(&wdt_counter)) {
  48                         printk(KERN_WARNING "Avila watchdog expired, expect a reboot soon!\n");
  49                         clear_bit(WDT_RUNNING, &wdt_status);
  50                         return;
  51                 }
  52         }
  53
  54         /* strobe to the watchdog */
  55         gpio_line_set(14, IXP4XX_GPIO_HIGH);
  56         gpio_line_set(14, IXP4XX_GPIO_LOW);
  57
  58         mod_timer(&wdt_timer, jiffies + msecs_to_jiffies(500));
  59 }
  60
  61 static void wdt_enable(void)
  62 {
  63         atomic_set(&wdt_counter, heartbeat * 2);
  64
  65         /* Disable clock generator output on GPIO 14/15 */
  66         *IXP4XX_GPIO_GPCLKR &= ~(1 << 8);
  67
  68         /* activate GPIO 14 out */
  69         gpio_line_config(14, IXP4XX_GPIO_OUT);
  70         gpio_line_set(14, IXP4XX_GPIO_LOW);
  71
  72         if (!test_bit(WDT_RUNNING, &wdt_status))
  73                 wdt_refresh(0);
  74         set_bit(WDT_RUNNING, &wdt_status);
  75 }
  76
  77 static void wdt_disable(void)
  78 {
  79         /* Re-enable clock generator output on GPIO 14/15 */
  80         *IXP4XX_GPIO_GPCLKR |= (1 << 8);
  81 }
  82
  83 static int avila_wdt_open(struct inode *inode, struct file *file)
  84 {
  85         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
  86                 return -EBUSY;
  87
  88         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
  89         wdt_enable();
  90         return nonseekable_open(inode, file);
  91 }
  92
  93 static ssize_t
  94 avila_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
  95 {
  96         if (len) {
  97                 if (!nowayout) {
  98                         size_t i;
  99
 100                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 101
 102                         for (i = 0; i != len; i++) {
 103                                 char c;
 104
 105                                 if (get_user(c, data + i))
 106                                         return -EFAULT;
 107                                 if (c == 'V')
 108                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 109                         }
 110                 }
 111                 wdt_enable();
 112         }
 113         return len;
 114 }
 115
 116 static struct watchdog_info ident = {
 117         .options        = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
 118                           WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 119         .identity       = "Avila Watchdog",
 120 };
 121
 122
 123 static long avila_wdt_ioctl(struct file *file, unsigned int cmd,
 124                                                         unsigned long arg)
 125 {
 126         int ret = -ENOTTY;
 127         int time;
 128
 129         switch (cmd) {
 130         case WDIOC_GETSUPPORT:
 131                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
 132                                    sizeof(ident)) ? -EFAULT : 0;
 133                 break;
 134
 135         case WDIOC_GETSTATUS:
 136                 ret = put_user(0, (int *)arg);
 137                 break;
 138
 139         case WDIOC_KEEPALIVE:
 140                 wdt_enable();
 141                 ret = 0;
 142                 break;
 143
 144         case WDIOC_SETTIMEOUT:
 145                 ret = get_user(time, (int *)arg);
 146                 if (ret)
 147                         break;
 148
 149                 if (time <= 0 || time > 60) {
 150                         ret = -EINVAL;
 151                         break;
 152                 }
 153
 154                 heartbeat = time;
 155                 wdt_enable();
 156                 /* Fall through */
 157
 158         case WDIOC_GETTIMEOUT:
 159                 ret = put_user(heartbeat, (int *)arg);
 160                 break;
 161         }
 162         return ret;
 163 }
 164
 165 static int avila_wdt_release(struct inode *inode, struct file *file)
 166 {
 167         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 168                 wdt_disable();
 169         else
 170                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
 171                                         "timer will not stop\n");
 172         clear_bit(WDT_IN_USE, &wdt_status);
 173         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 174
 175         return 0;
 176 }
 177
 178
 179 static const struct file_operations avila_wdt_fops = {
 180         .owner          = THIS_MODULE,
 181         .llseek         = no_llseek,
 182         .write          = avila_wdt_write,
 183         .unlocked_ioctl = avila_wdt_ioctl,
 184         .open           = avila_wdt_open,
 185         .release        = avila_wdt_release,
 186 };
 187
 188 static struct miscdevice avila_wdt_miscdev = {
 189         .minor          = WATCHDOG_MINOR + 1,
 190         .name           = "avila_watchdog",
 191         .fops           = &avila_wdt_fops,
 192 };
 193
 194 static int __init avila_wdt_init(void)
 195 {
 196         int ret;
 197
 198         init_timer(&wdt_timer);
 199         wdt_timer.expires = 0;
 200         wdt_timer.data = 0;
 201         wdt_timer.function = wdt_refresh;
 202         ret = misc_register(&avila_wdt_miscdev);
 203         if (ret == 0)
 204                 printk(KERN_INFO "Avila Watchdog Timer: heartbeat %d sec\n",
 205                         heartbeat);
 206         return ret;
 207 }
 208
 209 static void __exit avila_wdt_exit(void)
 210 {
 211         misc_deregister(&avila_wdt_miscdev);
 212         del_timer(&wdt_timer);
 213         wdt_disable();
 214 }
 215
 216
 217 module_init(avila_wdt_init);
 218 module_exit(avila_wdt_exit);
 219
 220 MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
 221 MODULE_DESCRIPTION("Gateworks Avila Hardware Watchdog");
 222
 223 module_param(heartbeat, int, 0);
 224 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 20s)");
 225
 226 module_param(nowayout, int, 0);
 227 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
 228
 229 MODULE_LICENSE("GPL");
 230 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 231