drivers/char/watchdog/ixp4xx_wdt.c

   1 /*
   2  * drivers/watchdog/ixp4xx_wdt.c
   3  *
   4  * Watchdog driver for Intel IXP4xx network processors
   5  *
   6  * Author: Deepak Saxena <dsaxena@plexity.net>
   7  *
   8  * Copyright 2004 (c) MontaVista, Software, Inc.
   9  * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
  10  *
  11  * This file is licensed under  the terms of the GNU General Public
  12  * License version 2. This program is licensed "as is" without any
  13  * warranty of any kind, whether express or implied.
  14  */
  15
  16 #include <linux/config.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/types.h>
  20 #include <linux/kernel.h>
  21 #include <linux/fs.h>
  22 #include <linux/miscdevice.h>
  23 #include <linux/watchdog.h>
  24 #include <linux/init.h>
  25
  26 #include <asm/hardware.h>
  27 #include <asm/bitops.h>
  28 #include <asm/uaccess.h>
  29
  30 #ifdef CONFIG_WATCHDOG_NOWAYOUT
  31 static int nowayout = 1;
  32 #else
  33 static int nowayout = 0;
  34 #endif
  35 static int heartbeat = 60;      /* (secs) Default is 1 minute */
  36 static unsigned long wdt_status;
  37 static unsigned long boot_status;
  38
  39 #define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
  40
  41 #define WDT_IN_USE              0
  42 #define WDT_OK_TO_CLOSE         1
  43
  44 static void
  45 wdt_enable(void)
  46 {
  47         *IXP4XX_OSWK = IXP4XX_WDT_KEY;
  48         *IXP4XX_OSWE = 0;
  49         *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
  50         *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
  51         *IXP4XX_OSWK = 0;
  52 }
  53
  54 static void
  55 wdt_disable(void)
  56 {
  57         *IXP4XX_OSWK = IXP4XX_WDT_KEY;
  58         *IXP4XX_OSWE = 0;
  59         *IXP4XX_OSWK = 0;
  60 }
  61
  62 static int
  63 ixp4xx_wdt_open(struct inode *inode, struct file *file)
  64 {
  65         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
  66                 return -EBUSY;
  67
  68         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
  69
  70         wdt_enable();
  71
  72         return nonseekable_open(inode, file);
  73 }
  74
  75 static ssize_t
  76 ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
  77 {
  78         if (len) {
  79                 if (!nowayout) {
  80                         size_t i;
  81
  82                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
  83
  84                         for (i = 0; i != len; i++) {
  85                                 char c;
  86
  87                                 if (get_user(c, data + i))
  88                                         return -EFAULT;
  89                                 if (c == 'V')
  90                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
  91                         }
  92                 }
  93                 wdt_enable();
  94         }
  95
  96         return len;
  97 }
  98
  99 static struct watchdog_info ident = {
 100         .options        = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
 101                           WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 102         .identity       = "IXP4xx Watchdog",
 103 };
 104
 105
 106 static int
 107 ixp4xx_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 108                         unsigned long arg)
 109 {
 110         int ret = -ENOIOCTLCMD;
 111         int time;
 112
 113         switch (cmd) {
 114         case WDIOC_GETSUPPORT:
 115                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
 116                                    sizeof(ident)) ? -EFAULT : 0;
 117                 break;
 118
 119         case WDIOC_GETSTATUS:
 120                 ret = put_user(0, (int *)arg);
 121                 break;
 122
 123         case WDIOC_GETBOOTSTATUS:
 124                 ret = put_user(boot_status, (int *)arg);
 125                 break;
 126
 127         case WDIOC_SETTIMEOUT:
 128                 ret = get_user(time, (int *)arg);
 129                 if (ret)
 130                         break;
 131
 132                 if (time <= 0 || time > 60) {
 133                         ret = -EINVAL;
 134                         break;
 135                 }
 136
 137                 heartbeat = time;
 138                 wdt_enable();
 139                 /* Fall through */
 140
 141         case WDIOC_GETTIMEOUT:
 142                 ret = put_user(heartbeat, (int *)arg);
 143                 break;
 144
 145         case WDIOC_KEEPALIVE:
 146                 wdt_enable();
 147                 ret = 0;
 148                 break;
 149         }
 150         return ret;
 151 }
 152
 153 static int
 154 ixp4xx_wdt_release(struct inode *inode, struct file *file)
 155 {
 156         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
 157                 wdt_disable();
 158         } else {
 159                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectdly - "
 160                                         "timer will not stop\n");
 161         }
 162
 163         clear_bit(WDT_IN_USE, &wdt_status);
 164         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 165
 166         return 0;
 167 }
 168
 169
 170 static struct file_operations ixp4xx_wdt_fops =
 171 {
 172         .owner          = THIS_MODULE,
 173         .llseek         = no_llseek,
 174         .write          = ixp4xx_wdt_write,
 175         .ioctl          = ixp4xx_wdt_ioctl,
 176         .open           = ixp4xx_wdt_open,
 177         .release        = ixp4xx_wdt_release,
 178 };
 179
 180 static struct miscdevice ixp4xx_wdt_miscdev =
 181 {
 182         .minor          = WATCHDOG_MINOR,
 183         .name           = "IXP4xx Watchdog",
 184         .fops           = &ixp4xx_wdt_fops,
 185 };
 186
 187 static int __init ixp4xx_wdt_init(void)
 188 {
 189         int ret;
 190         unsigned long processor_id;
 191
 192         asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :);
 193         if (!(processor_id & 0xf)) {
 194                 printk("IXP4XXX Watchdog: Rev. A0 CPU detected - "
 195                         "watchdog disabled\n");
 196
 197                 return -ENODEV;
 198         }
 199
 200         ret = misc_register(&ixp4xx_wdt_miscdev);
 201         if (ret == 0)
 202                 printk("IXP4xx Watchdog Timer: heartbeat %d sec\n", heartbeat);
 203
 204         boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
 205                         WDIOF_CARDRESET : 0;
 206
 207         return ret;
 208 }
 209
 210 static void __exit ixp4xx_wdt_exit(void)
 211 {
 212         misc_deregister(&ixp4xx_wdt_miscdev);
 213 }
 214
 215
 216 module_init(ixp4xx_wdt_init);
 217 module_exit(ixp4xx_wdt_exit);
 218
 219 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net">);
 220 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
 221
 222 module_param(heartbeat, int, 0);
 223 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
 224
 225 module_param(nowayout, int, 0);
 226 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
 227
 228 MODULE_LICENSE("GPL");
 229 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 230