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 <linux/io.h>
  34 #include <linux/uaccess.h>
  35 #include <linux/watchdog.h>
  36
  37 /* adjustable parameters */
  38
  39 static int verbose;
  40 static int port = 0x91;
  41 static int ticks = 10000;
  42 static spinlock_t cpu5wdt_lock;
  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         spin_lock(&cpu5wdt_lock);
  80         /* keep watchdog alive */
  81         outb(1, port + CPU5WDT_TRIGGER_REG);
  82
  83         /* requeue?? */
  84         if (cpu5wdt_device.queue && ticks)
  85                 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
  86         else {
  87                 /* ticks doesn't matter anyway */
  88                 complete(&cpu5wdt_device.stop);
  89         }
  90         spin_unlock(&cpu5wdt_lock);
  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         unsigned long flags;
 106
 107         spin_lock_irqsave(&cpu5wdt_lock, flags);
 108         if (!cpu5wdt_device.queue) {
 109                 cpu5wdt_device.queue = 1;
 110                 outb(0, port + CPU5WDT_TIME_A_REG);
 111                 outb(0, port + CPU5WDT_TIME_B_REG);
 112                 outb(1, port + CPU5WDT_MODE_REG);
 113                 outb(0, port + CPU5WDT_RESET_REG);
 114                 outb(0, port + CPU5WDT_ENABLE_REG);
 115                 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
 116         }
 117         /* if process dies, counter is not decremented */
 118         cpu5wdt_device.running++;
 119         spin_unlock_irqrestore(&cpu5wdt_lock, flags);
 120 }
 121
 122 static int cpu5wdt_stop(void)
 123 {
 124         unsigned long flags;
 125
 126         spin_lock_irqsave(&cpu5wdt_lock, flags);
 127         if (cpu5wdt_device.running)
 128                 cpu5wdt_device.running = 0;
 129         ticks = cpu5wdt_device.default_ticks;
 130         spin_unlock_irqrestore(&cpu5wdt_lock, flags);
 131         if (verbose)
 132                 printk(KERN_CRIT PFX "stop not possible\n");
 133         return -EIO;
 134 }
 135
 136 /* filesystem operations */
 137
 138 static int cpu5wdt_open(struct inode *inode, struct file *file)
 139 {
 140         if (test_and_set_bit(0, &cpu5wdt_device.inuse))
 141                 return -EBUSY;
 142         return nonseekable_open(inode, file);
 143 }
 144
 145 static int cpu5wdt_release(struct inode *inode, struct file *file)
 146 {
 147         clear_bit(0, &cpu5wdt_device.inuse);
 148         return 0;
 149 }
 150
 151 static long cpu5wdt_ioctl(struct file *file, unsigned int cmd,
 152                                                 unsigned long arg)
 153 {
 154         void __user *argp = (void __user *)arg;
 155         int __user *p = argp;
 156         unsigned int value;
 157         static const struct watchdog_info ident = {
 158                 .options = WDIOF_CARDRESET,
 159                 .identity = "CPU5 WDT",
 160         };
 161
 162         switch (cmd) {
 163         case WDIOC_GETSUPPORT:
 164                 if (copy_to_user(argp, &ident, sizeof(ident)))
 165                         return -EFAULT;
 166                 break;
 167         case WDIOC_GETSTATUS:
 168                 value = inb(port + CPU5WDT_STATUS_REG);
 169                 value = (value >> 2) & 1;
 170                 return put_user(value, p);
 171         case WDIOC_GETBOOTSTATUS:
 172                 return put_user(0, p);
 173         case WDIOC_SETOPTIONS:
 174                 if (get_user(value, p))
 175                         return -EFAULT;
 176                 if (value & WDIOS_ENABLECARD)
 177                         cpu5wdt_start();
 178                 if (value & WDIOS_DISABLECARD)
 179                         cpu5wdt_stop();
 180                 break;
 181         case WDIOC_KEEPALIVE:
 182                 cpu5wdt_reset();
 183                 break;
 184         default:
 185                 return -ENOTTY;
 186         }
 187         return 0;
 188 }
 189
 190 static ssize_t cpu5wdt_write(struct file *file, const char __user *buf,
 191                                                 size_t count, loff_t *ppos)
 192 {
 193         if (!count)
 194                 return -EIO;
 195         cpu5wdt_reset();
 196         return count;
 197 }
 198
 199 static const struct file_operations cpu5wdt_fops = {
 200         .owner          = THIS_MODULE,
 201         .llseek         = no_llseek,
 202         .unlocked_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
 223                                 "port=0x%x, verbose=%i\n", port, verbose);
 224
 225         init_completion(&cpu5wdt_device.stop);
 226         spin_lock_init(&cpu5wdt_lock);
 227         cpu5wdt_device.queue = 0;
 228         setup_timer(&cpu5wdt_device.timer, cpu5wdt_trigger, 0);
 229         cpu5wdt_device.default_ticks = ticks;
 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         err = misc_register(&cpu5wdt_misc);
 244         if (err < 0) {
 245                 printk(KERN_ERR PFX "misc_register failed\n");
 246                 goto no_misc;
 247         }
 248
 249
 250         printk(KERN_INFO PFX "init success\n");
 251         return 0;
 252
 253 no_misc:
 254         release_region(port, CPU5WDT_EXTENT);
 255 no_port:
 256         return err;
 257 }
 258
 259 static int __devinit cpu5wdt_init_module(void)
 260 {
 261         return cpu5wdt_init();
 262 }
 263
 264 static void __devexit cpu5wdt_exit(void)
 265 {
 266         if (cpu5wdt_device.queue) {
 267                 cpu5wdt_device.queue = 0;
 268                 wait_for_completion(&cpu5wdt_device.stop);
 269         }
 270
 271         misc_deregister(&cpu5wdt_misc);
 272
 273         release_region(port, CPU5WDT_EXTENT);
 274
 275 }
 276
 277 static void __devexit cpu5wdt_exit_module(void)
 278 {
 279         cpu5wdt_exit();
 280 }
 281
 282 /* module entry points */
 283
 284 module_init(cpu5wdt_init_module);
 285 module_exit(cpu5wdt_exit_module);
 286
 287 MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
 288 MODULE_DESCRIPTION("sma cpu5 watchdog driver");
 289 MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
 290 MODULE_LICENSE("GPL");
 291 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 292
 293 module_param(port, int, 0);
 294 MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
 295
 296 module_param(verbose, int, 0);
 297 MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
 298
 299 module_param(ticks, int, 0);
 300 MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");