drivers/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/completion.h>
  32 #include <linux/jiffies.h>
  33 #include <asm/io.h>
  34 #include <asm/uaccess.h>
  35
  36 #include <linux/watchdog.h>
  37
  38 /* adjustable parameters */
  39
  40 static int verbose = 0;
  41 static int port = 0x91;
  42 static int ticks = 10000;
  43
  44 #define PFX                     "cpu5wdt: "
  45
  46 #define CPU5WDT_EXTENT          0x0A
  47
  48 #define CPU5WDT_STATUS_REG      0x00
  49 #define CPU5WDT_TIME_A_REG      0x02
  50 #define CPU5WDT_TIME_B_REG      0x03
  51 #define CPU5WDT_MODE_REG        0x04
  52 #define CPU5WDT_TRIGGER_REG     0x07
  53 #define CPU5WDT_ENABLE_REG      0x08
  54 #define CPU5WDT_RESET_REG       0x09
  55
  56 #define CPU5WDT_INTERVAL        (HZ/10+1)
  57
  58 /* some device data */
  59
  60 static struct {
  61         struct completion stop;
  62         int running;
  63         struct timer_list timer;
  64         int queue;
  65         int default_ticks;
  66         unsigned long inuse;
  67 } cpu5wdt_device;
  68
  69 /* generic helper functions */
  70
  71 static void cpu5wdt_trigger(unsigned long unused)
  72 {
  73         if ( verbose > 2 )
  74                 printk(KERN_DEBUG PFX "trigger at %i ticks\n", ticks);
  75
  76         if( cpu5wdt_device.running )
  77                 ticks--;
  78
  79         /* keep watchdog alive */
  80         outb(1, port + CPU5WDT_TRIGGER_REG);
  81
  82         /* requeue?? */
  83         if (cpu5wdt_device.queue && ticks)
  84                 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
  85         else {
  86                 /* ticks doesn't matter anyway */
  87                 complete(&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                 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
 111         }
 112         /* if process dies, counter is not decremented */
 113         cpu5wdt_device.running++;
 114 }
 115
 116 static int cpu5wdt_stop(void)
 117 {
 118         if ( cpu5wdt_device.running )
 119                 cpu5wdt_device.running = 0;
 120
 121         ticks = cpu5wdt_device.default_ticks;
 122
 123         if ( verbose )
 124                 printk(KERN_CRIT PFX "stop not possible\n");
 125
 126         return -EIO;
 127 }
 128
 129 /* filesystem operations */
 130
 131 static int cpu5wdt_open(struct inode *inode, struct file *file)
 132 {
 133         if ( test_and_set_bit(0, &cpu5wdt_device.inuse) )
 134                 return -EBUSY;
 135
 136         return nonseekable_open(inode, file);
 137 }
 138
 139 static int cpu5wdt_release(struct inode *inode, struct file *file)
 140 {
 141         clear_bit(0, &cpu5wdt_device.inuse);
 142         return 0;
 143 }
 144
 145 static int cpu5wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 146 {
 147         void __user *argp = (void __user *)arg;
 148         unsigned int value;
 149         static struct watchdog_info ident =
 150         {
 151                 .options = WDIOF_CARDRESET,
 152                 .identity = "CPU5 WDT",
 153         };
 154
 155         switch(cmd) {
 156                 case WDIOC_KEEPALIVE:
 157                         cpu5wdt_reset();
 158                         break;
 159                 case WDIOC_GETSTATUS:
 160                         value = inb(port + CPU5WDT_STATUS_REG);
 161                         value = (value >> 2) & 1;
 162                         if ( copy_to_user(argp, &value, sizeof(int)) )
 163                                 return -EFAULT;
 164                         break;
 165                 case WDIOC_GETBOOTSTATUS:
 166                         if ( copy_to_user(argp, &value, sizeof(int)) )
 167                                 return -EFAULT;
 168                         break;
 169                 case WDIOC_GETSUPPORT:
 170                         if ( copy_to_user(argp, &ident, sizeof(ident)) )
 171                                 return -EFAULT;
 172                         break;
 173                 case WDIOC_SETOPTIONS:
 174                         if ( copy_from_user(&value, argp, sizeof(int)) )
 175                                 return -EFAULT;
 176                         switch(value) {
 177                                 case WDIOS_ENABLECARD:
 178                                         cpu5wdt_start();
 179                                         break;
 180                                 case WDIOS_DISABLECARD:
 181                                         return cpu5wdt_stop();
 182                                 default:
 183                                         return -EINVAL;
 184                         }
 185                         break;
 186                 default:
 187                         return -ENOTTY;
 188         }
 189         return 0;
 190 }
 191
 192 static ssize_t cpu5wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 193 {
 194         if ( !count )
 195                 return -EIO;
 196
 197         cpu5wdt_reset();
 198
 199         return count;
 200 }
 201
 202 static const struct file_operations cpu5wdt_fops = {
 203         .owner          = THIS_MODULE,
 204         .llseek         = no_llseek,
 205         .ioctl          = cpu5wdt_ioctl,
 206         .open           = cpu5wdt_open,
 207         .write          = cpu5wdt_write,
 208         .release        = cpu5wdt_release,
 209 };
 210
 211 static struct miscdevice cpu5wdt_misc = {
 212         .minor  = WATCHDOG_MINOR,
 213         .name   = "watchdog",
 214         .fops   = &cpu5wdt_fops,
 215 };
 216
 217 /* init/exit function */
 218
 219 static int __devinit cpu5wdt_init(void)
 220 {
 221         unsigned int val;
 222         int err;
 223
 224         if ( verbose )
 225                 printk(KERN_DEBUG PFX "port=0x%x, verbose=%i\n", port, verbose);
 226
 227         if ( !request_region(port, CPU5WDT_EXTENT, PFX) ) {
 228                 printk(KERN_ERR PFX "request_region failed\n");
 229                 err = -EBUSY;
 230                 goto no_port;
 231         }
 232
 233         if ( (err = misc_register(&cpu5wdt_misc)) < 0 ) {
 234                 printk(KERN_ERR PFX "misc_register failed\n");
 235                 goto no_misc;
 236         }
 237
 238         /* watchdog reboot? */
 239         val = inb(port + CPU5WDT_STATUS_REG);
 240         val = (val >> 2) & 1;
 241         if ( !val )
 242                 printk(KERN_INFO PFX "sorry, was my fault\n");
 243
 244         init_completion(&cpu5wdt_device.stop);
 245         cpu5wdt_device.queue = 0;
 246
 247         clear_bit(0, &cpu5wdt_device.inuse);
 248
 249         setup_timer(&cpu5wdt_device.timer, cpu5wdt_trigger, 0);
 250
 251         cpu5wdt_device.default_ticks = ticks;
 252
 253         printk(KERN_INFO PFX "init success\n");
 254
 255         return 0;
 256
 257 no_misc:
 258         release_region(port, CPU5WDT_EXTENT);
 259 no_port:
 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                 wait_for_completion(&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");