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 <asm/io.h>
  32 #include <asm/uaccess.h>
  33
  34 #include <linux/watchdog.h>
  35
  36 /* adjustable parameters */
  37
  38 static int verbose = 0;
  39 static int port = 0x91;
  40 static int ticks = 10000;
  41
  42 #define PFX                     "cpu5wdt: "
  43
  44 #define CPU5WDT_EXTENT          0x0A
  45
  46 #define CPU5WDT_STATUS_REG      0x00
  47 #define CPU5WDT_TIME_A_REG      0x02
  48 #define CPU5WDT_TIME_B_REG      0x03
  49 #define CPU5WDT_MODE_REG        0x04
  50 #define CPU5WDT_TRIGGER_REG     0x07
  51 #define CPU5WDT_ENABLE_REG      0x08
  52 #define CPU5WDT_RESET_REG       0x09
  53
  54 #define CPU5WDT_INTERVAL        (HZ/10+1)
  55
  56 /* some device data */
  57
  58 static struct {
  59         struct semaphore stop;
  60         volatile int running;
  61         struct timer_list timer;
  62         volatile int queue;
  63         int default_ticks;
  64         unsigned long inuse;
  65 } cpu5wdt_device;
  66
  67 /* generic helper functions */
  68
  69 static void cpu5wdt_trigger(unsigned long unused)
  70 {
  71         if ( verbose > 2 )
  72                 printk(KERN_DEBUG PFX "trigger at %i ticks\n", ticks);
  73
  74         if( cpu5wdt_device.running )
  75                 ticks--;
  76
  77         /* keep watchdog alive */
  78         outb(1, port + CPU5WDT_TRIGGER_REG);
  79
  80         /* requeue?? */
  81         if( cpu5wdt_device.queue && ticks ) {
  82                 cpu5wdt_device.timer.expires = jiffies + CPU5WDT_INTERVAL;
  83                 add_timer(&cpu5wdt_device.timer);
  84         }
  85         else {
  86                 /* ticks doesn't matter anyway */
  87                 up(&cpu5wdt_device.stop);
  88         }
  89
  90 }
  91
  92 static void cpu5wdt_reset(void)
  93 {
  94         ticks = cpu5wdt_device.default_ticks;
  95
  96         if ( verbose )
  97                 printk(KERN_DEBUG PFX "reset (%i ticks)\n", (int) ticks);
  98
  99 }
 100
 101 static void cpu5wdt_start(void)
 102 {
 103         if ( !cpu5wdt_device.queue ) {
 104                 cpu5wdt_device.queue = 1;
 105                 outb(0, port + CPU5WDT_TIME_A_REG);
 106                 outb(0, port + CPU5WDT_TIME_B_REG);
 107                 outb(1, port + CPU5WDT_MODE_REG);
 108                 outb(0, port + CPU5WDT_RESET_REG);
 109                 outb(0, port + CPU5WDT_ENABLE_REG);
 110                 cpu5wdt_device.timer.expires = jiffies + CPU5WDT_INTERVAL;
 111                 add_timer(&cpu5wdt_device.timer);
 112         }
 113         /* if process dies, counter is not decremented */
 114         cpu5wdt_device.running++;
 115 }
 116
 117 static int cpu5wdt_stop(void)
 118 {
 119         if ( cpu5wdt_device.running )
 120                 cpu5wdt_device.running = 0;
 121
 122         ticks = cpu5wdt_device.default_ticks;
 123
 124         if ( verbose )
 125                 printk(KERN_CRIT PFX "stop not possible\n");
 126
 127         return -EIO;
 128 }
 129
 130 /* filesystem operations */
 131
 132 static int cpu5wdt_open(struct inode *inode, struct file *file)
 133 {
 134         if ( test_and_set_bit(0, &cpu5wdt_device.inuse) )
 135                 return -EBUSY;
 136
 137         return nonseekable_open(inode, file);
 138 }
 139
 140 static int cpu5wdt_release(struct inode *inode, struct file *file)
 141 {
 142         clear_bit(0, &cpu5wdt_device.inuse);
 143         return 0;
 144 }
 145
 146 static int cpu5wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 147 {
 148         void __user *argp = (void __user *)arg;
 149         unsigned int value;
 150         static struct watchdog_info ident =
 151         {
 152                 .options = WDIOF_CARDRESET,
 153                 .identity = "CPU5 WDT",
 154         };
 155
 156         switch(cmd) {
 157                 case WDIOC_KEEPALIVE:
 158                         cpu5wdt_reset();
 159                         break;
 160                 case WDIOC_GETSTATUS:
 161                         value = inb(port + CPU5WDT_STATUS_REG);
 162                         value = (value >> 2) & 1;
 163                         if ( copy_to_user(argp, &value, sizeof(int)) )
 164                                 return -EFAULT;
 165                         break;
 166                 case WDIOC_GETSUPPORT:
 167                         if ( copy_to_user(argp, &ident, sizeof(ident)) )
 168                                 return -EFAULT;
 169                         break;
 170                 case WDIOC_SETOPTIONS:
 171                         if ( copy_from_user(&value, argp, sizeof(int)) )
 172                                 return -EFAULT;
 173                         switch(value) {
 174                                 case WDIOS_ENABLECARD:
 175                                         cpu5wdt_start();
 176                                         break;
 177                                 case WDIOS_DISABLECARD:
 178                                         return cpu5wdt_stop();
 179                                 default:
 180                                         return -EINVAL;
 181                         }
 182                         break;
 183                 default:
 184                         return -ENOIOCTLCMD;
 185         }
 186         return 0;
 187 }
 188
 189 static ssize_t cpu5wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 190 {
 191         if ( !count )
 192                 return -EIO;
 193
 194         cpu5wdt_reset();
 195
 196         return count;
 197 }
 198
 199 static struct file_operations cpu5wdt_fops = {
 200         .owner          = THIS_MODULE,
 201         .llseek         = no_llseek,
 202         .ioctl          = cpu5wdt_ioctl,
 203         .open           = cpu5wdt_open,
 204         .write          = cpu5wdt_write,
 205         .release        = cpu5wdt_release,
 206 };
 207
 208 static struct miscdevice cpu5wdt_misc = {
 209         .minor  = WATCHDOG_MINOR,
 210         .name   = "watchdog",
 211         .fops   = &cpu5wdt_fops,
 212 };
 213
 214 /* init/exit function */
 215
 216 static int __devinit cpu5wdt_init(void)
 217 {
 218         unsigned int val;
 219         int err;
 220
 221         if ( verbose )
 222                 printk(KERN_DEBUG PFX "port=0x%x, verbose=%i\n", port, verbose);
 223
 224         if ( (err = misc_register(&cpu5wdt_misc)) < 0 ) {
 225                 printk(KERN_ERR PFX "misc_register failed\n");
 226                 goto no_misc;
 227         }
 228
 229         if ( !request_region(port, CPU5WDT_EXTENT, PFX) ) {
 230                 printk(KERN_ERR PFX "request_region failed\n");
 231                 err = -EBUSY;
 232                 goto no_port;
 233         }
 234
 235         /* watchdog reboot? */
 236         val = inb(port + CPU5WDT_STATUS_REG);
 237         val = (val >> 2) & 1;
 238         if ( !val )
 239                 printk(KERN_INFO PFX "sorry, was my fault\n");
 240
 241         init_MUTEX_LOCKED(&cpu5wdt_device.stop);
 242         cpu5wdt_device.queue = 0;
 243
 244         clear_bit(0, &cpu5wdt_device.inuse);
 245
 246         init_timer(&cpu5wdt_device.timer);
 247         cpu5wdt_device.timer.function = cpu5wdt_trigger;
 248         cpu5wdt_device.timer.data = 0;
 249
 250         cpu5wdt_device.default_ticks = ticks;
 251
 252         printk(KERN_INFO PFX "init success\n");
 253
 254         return 0;
 255
 256 no_port:
 257         misc_deregister(&cpu5wdt_misc);
 258 no_misc:
 259         return err;
 260 }
 261
 262 static int __devinit cpu5wdt_init_module(void)
 263 {
 264         return cpu5wdt_init();
 265 }
 266
 267 static void __devexit cpu5wdt_exit(void)
 268 {
 269         if ( cpu5wdt_device.queue ) {
 270                 cpu5wdt_device.queue = 0;
 271                 down(&cpu5wdt_device.stop);
 272         }
 273
 274         misc_deregister(&cpu5wdt_misc);
 275
 276         release_region(port, CPU5WDT_EXTENT);
 277
 278 }
 279
 280 static void __devexit cpu5wdt_exit_module(void)
 281 {
 282         cpu5wdt_exit();
 283 }
 284
 285 /* module entry points */
 286
 287 module_init(cpu5wdt_init_module);
 288 module_exit(cpu5wdt_exit_module);
 289
 290 MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
 291 MODULE_DESCRIPTION("sma cpu5 watchdog driver");
 292 MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
 293 MODULE_LICENSE("GPL");
 294 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 295
 296 module_param(port, int, 0);
 297 MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
 298
 299 module_param(verbose, int, 0);
 300 MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
 301
 302 module_param(ticks, int, 0);
 303 MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");