drivers/char/watchdog/cpu5wdt.c

   1 /*
   2  * sma cpu5 watchdog driver
   3  *
   4  * Copyright (C) 2003 Heiko Ronsdorf <hero@ihg.uni-duisburg.de>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  *
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/moduleparam.h>
  24 #include <linux/types.h>
  25 #include <linux/errno.h>
  26 #include <linux/miscdevice.h>
  27 #include <linux/fs.h>
  28 #include <linux/init.h>
  29 #include <linux/ioport.h>
  30 #include <linux/timer.h>
  31 #include <linux/jiffies.h>
  32 #include <asm/io.h>
  33 #include <asm/uaccess.h>
  34
  35 #include <linux/watchdog.h>
  36
  37 /* adjustable parameters */
  38
  39 static int verbose = 0;
  40 static int port = 0x91;
  41 static int ticks = 10000;
  42
  43 #define PFX                     "cpu5wdt: "
  44
  45 #define CPU5WDT_EXTENT          0x0A
  46
  47 #define CPU5WDT_STATUS_REG      0x00
  48 #define CPU5WDT_TIME_A_REG      0x02
  49 #define CPU5WDT_TIME_B_REG      0x03
  50 #define CPU5WDT_MODE_REG        0x04
  51 #define CPU5WDT_TRIGGER_REG     0x07
  52 #define CPU5WDT_ENABLE_REG      0x08
  53 #define CPU5WDT_RESET_REG       0x09
  54
  55 #define CPU5WDT_INTERVAL        (HZ/10+1)
  56
  57 /* some device data */
  58
  59 static struct {
  60         struct semaphore stop;
  61         volatile int running;
  62         struct timer_list timer;
  63         volatile int queue;
  64         int default_ticks;
  65         unsigned long inuse;
  66 } cpu5wdt_device;
  67
  68 /* generic helper functions */
  69
  70 static void cpu5wdt_trigger(unsigned long unused)
  71 {
  72         if ( verbose > 2 )
  73                 printk(KERN_DEBUG PFX "trigger at %i ticks\n", ticks);
  74
  75         if( cpu5wdt_device.running )
  76                 ticks--;
  77
  78         /* keep watchdog alive */
  79         outb(1, port + CPU5WDT_TRIGGER_REG);
  80
  81         /* requeue?? */
  82         if( cpu5wdt_device.queue && ticks ) {
  83                 cpu5wdt_device.timer.expires = jiffies + CPU5WDT_INTERVAL;
  84                 add_timer(&cpu5wdt_device.timer);
  85         }
  86         else {
  87                 /* ticks doesn't matter anyway */
  88                 up(&cpu5wdt_device.stop);
  89         }
  90
  91 }
  92
  93 static void cpu5wdt_reset(void)
  94 {
  95         ticks = cpu5wdt_device.default_ticks;
  96
  97         if ( verbose )
  98                 printk(KERN_DEBUG PFX "reset (%i ticks)\n", (int) ticks);
  99
 100 }
 101
 102 static void cpu5wdt_start(void)
 103 {
 104         if ( !cpu5wdt_device.queue ) {
 105                 cpu5wdt_device.queue = 1;
 106                 outb(0, port + CPU5WDT_TIME_A_REG);
 107                 outb(0, port + CPU5WDT_TIME_B_REG);
 108                 outb(1, port + CPU5WDT_MODE_REG);
 109                 outb(0, port + CPU5WDT_RESET_REG);
 110                 outb(0, port + CPU5WDT_ENABLE_REG);
 111                 cpu5wdt_device.timer.expires = jiffies + CPU5WDT_INTERVAL;
 112                 add_timer(&cpu5wdt_device.timer);
 113         }
 114         /* if process dies, counter is not decremented */
 115         cpu5wdt_device.running++;
 116 }
 117
 118 static int cpu5wdt_stop(void)
 119 {
 120         if ( cpu5wdt_device.running )
 121                 cpu5wdt_device.running = 0;
 122
 123         ticks = cpu5wdt_device.default_ticks;
 124
 125         if ( verbose )
 126                 printk(KERN_CRIT PFX "stop not possible\n");
 127
 128         return -EIO;
 129 }
 130
 131 /* filesystem operations */
 132
 133 static int cpu5wdt_open(struct inode *inode, struct file *file)
 134 {
 135         if ( test_and_set_bit(0, &cpu5wdt_device.inuse) )
 136                 return -EBUSY;
 137
 138         return nonseekable_open(inode, file);
 139 }
 140
 141 static int cpu5wdt_release(struct inode *inode, struct file *file)
 142 {
 143         clear_bit(0, &cpu5wdt_device.inuse);
 144         return 0;
 145 }
 146
 147 static int cpu5wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 148 {
 149         void __user *argp = (void __user *)arg;
 150         unsigned int value;
 151         static struct watchdog_info ident =
 152         {
 153                 .options = WDIOF_CARDRESET,
 154                 .identity = "CPU5 WDT",
 155         };
 156
 157         switch(cmd) {
 158                 case WDIOC_KEEPALIVE:
 159                         cpu5wdt_reset();
 160                         break;
 161                 case WDIOC_GETSTATUS:
 162                         value = inb(port + CPU5WDT_STATUS_REG);
 163                         value = (value >> 2) & 1;
 164                         if ( copy_to_user(argp, &value, sizeof(int)) )
 165                                 return -EFAULT;
 166                         break;
 167                 case WDIOC_GETSUPPORT:
 168                         if ( copy_to_user(argp, &ident, sizeof(ident)) )
 169                                 return -EFAULT;
 170                         break;
 171                 case WDIOC_SETOPTIONS:
 172                         if ( copy_from_user(&value, argp, sizeof(int)) )
 173                                 return -EFAULT;
 174                         switch(value) {
 175                                 case WDIOS_ENABLECARD:
 176                                         cpu5wdt_start();
 177                                         break;
 178                                 case WDIOS_DISABLECARD:
 179                                         return cpu5wdt_stop();
 180                                 default:
 181                                         return -EINVAL;
 182                         }
 183                         break;
 184                 default:
 185                         return -ENOIOCTLCMD;
 186         }
 187         return 0;
 188 }
 189
 190 static ssize_t cpu5wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 191 {
 192         if ( !count )
 193                 return -EIO;
 194
 195         cpu5wdt_reset();
 196
 197         return count;
 198 }
 199
 200 static struct file_operations cpu5wdt_fops = {
 201         .owner          = THIS_MODULE,
 202         .llseek         = no_llseek,
 203         .ioctl          = cpu5wdt_ioctl,
 204         .open           = cpu5wdt_open,
 205         .write          = cpu5wdt_write,
 206         .release        = cpu5wdt_release,
 207 };
 208
 209 static struct miscdevice cpu5wdt_misc = {
 210         .minor  = WATCHDOG_MINOR,
 211         .name   = "watchdog",
 212         .fops   = &cpu5wdt_fops,
 213 };
 214
 215 /* init/exit function */
 216
 217 static int __devinit cpu5wdt_init(void)
 218 {
 219         unsigned int val;
 220         int err;
 221
 222         if ( verbose )
 223                 printk(KERN_DEBUG PFX "port=0x%x, verbose=%i\n", port, verbose);
 224
 225         if ( (err = misc_register(&cpu5wdt_misc)) < 0 ) {
 226                 printk(KERN_ERR PFX "misc_register failed\n");
 227                 goto no_misc;
 228         }
 229
 230         if ( !request_region(port, CPU5WDT_EXTENT, PFX) ) {
 231                 printk(KERN_ERR PFX "request_region failed\n");
 232                 err = -EBUSY;
 233                 goto no_port;
 234         }
 235
 236         /* watchdog reboot? */
 237         val = inb(port + CPU5WDT_STATUS_REG);
 238         val = (val >> 2) & 1;
 239         if ( !val )
 240                 printk(KERN_INFO PFX "sorry, was my fault\n");
 241
 242         init_MUTEX_LOCKED(&cpu5wdt_device.stop);
 243         cpu5wdt_device.queue = 0;
 244
 245         clear_bit(0, &cpu5wdt_device.inuse);
 246
 247         init_timer(&cpu5wdt_device.timer);
 248         cpu5wdt_device.timer.function = cpu5wdt_trigger;
 249         cpu5wdt_device.timer.data = 0;
 250
 251         cpu5wdt_device.default_ticks = ticks;
 252
 253         printk(KERN_INFO PFX "init success\n");
 254
 255         return 0;
 256
 257 no_port:
 258         misc_deregister(&cpu5wdt_misc);
 259 no_misc:
 260         return err;
 261 }
 262
 263 static int __devinit cpu5wdt_init_module(void)
 264 {
 265         return cpu5wdt_init();
 266 }
 267
 268 static void __devexit cpu5wdt_exit(void)
 269 {
 270         if ( cpu5wdt_device.queue ) {
 271                 cpu5wdt_device.queue = 0;
 272                 down(&cpu5wdt_device.stop);
 273         }
 274
 275         misc_deregister(&cpu5wdt_misc);
 276
 277         release_region(port, CPU5WDT_EXTENT);
 278
 279 }
 280
 281 static void __devexit cpu5wdt_exit_module(void)
 282 {
 283         cpu5wdt_exit();
 284 }
 285
 286 /* module entry points */
 287
 288 module_init(cpu5wdt_init_module);
 289 module_exit(cpu5wdt_exit_module);
 290
 291 MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
 292 MODULE_DESCRIPTION("sma cpu5 watchdog driver");
 293 MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
 294 MODULE_LICENSE("GPL");
 295 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 296
 297 module_param(port, int, 0);
 298 MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
 299
 300 module_param(verbose, int, 0);
 301 MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
 302
 303 module_param(ticks, int, 0);
 304 MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");