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