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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  23
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/types.h>
  27 #include <linux/errno.h>
  28 #include <linux/miscdevice.h>
  29 #include <linux/fs.h>
  30 #include <linux/ioport.h>
  31 #include <linux/timer.h>
  32 #include <linux/completion.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/io.h>
  35 #include <linux/uaccess.h>
  36 #include <linux/watchdog.h>
  37
  38 /* adjustable parameters */
  39
  40 static int verbose;
  41 static int port = 0x91;
  42 static int ticks = 10000;
  43 static DEFINE_SPINLOCK(cpu5wdt_lock);
  44
  45 #define PFX                     "cpu5wdt: "
  46
  47 #define CPU5WDT_EXTENT          0x0A
  48
  49 #define CPU5WDT_STATUS_REG      0x00
  50 #define CPU5WDT_TIME_A_REG      0x02
  51 #define CPU5WDT_TIME_B_REG      0x03
  52 #define CPU5WDT_MODE_REG        0x04
  53 #define CPU5WDT_TRIGGER_REG     0x07
  54 #define CPU5WDT_ENABLE_REG      0x08
  55 #define CPU5WDT_RESET_REG       0x09
  56
  57 #define CPU5WDT_INTERVAL        (HZ/10+1)
  58
  59 /* some device data */
  60
  61 static struct {
  62         struct completion stop;
  63         int running;
  64         struct timer_list timer;
  65         int queue;
  66         int default_ticks;
  67         unsigned long inuse;
  68 } cpu5wdt_device;
  69
  70 /* generic helper functions */
  71
  72 static void cpu5wdt_trigger(unsigned long unused)
  73 {
  74         if (verbose > 2)
  75                 pr_debug("trigger at %i ticks\n", ticks);
  76
  77         if (cpu5wdt_device.running)
  78                 ticks--;
  79
  80         spin_lock(&cpu5wdt_lock);
  81         /* keep watchdog alive */
  82         outb(1, port + CPU5WDT_TRIGGER_REG);
  83
  84         /* requeue?? */
  85         if (cpu5wdt_device.queue && ticks)
  86                 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
  87         else {
  88                 /* ticks doesn't matter anyway */
  89                 complete(&cpu5wdt_device.stop);
  90         }
  91         spin_unlock(&cpu5wdt_lock);
  92
  93 }
  94
  95 static void cpu5wdt_reset(void)
  96 {
  97         ticks = cpu5wdt_device.default_ticks;
  98
  99         if (verbose)
 100                 pr_debug("reset (%i ticks)\n", (int) ticks);
 101
 102 }
 103
 104 static void cpu5wdt_start(void)
 105 {
 106         unsigned long flags;
 107
 108         spin_lock_irqsave(&cpu5wdt_lock, flags);
 109         if (!cpu5wdt_device.queue) {
 110                 cpu5wdt_device.queue = 1;
 111                 outb(0, port + CPU5WDT_TIME_A_REG);
 112                 outb(0, port + CPU5WDT_TIME_B_REG);
 113                 outb(1, port + CPU5WDT_MODE_REG);
 114                 outb(0, port + CPU5WDT_RESET_REG);
 115                 outb(0, port + CPU5WDT_ENABLE_REG);
 116                 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
 117         }
 118         /* if process dies, counter is not decremented */
 119         cpu5wdt_device.running++;
 120         spin_unlock_irqrestore(&cpu5wdt_lock, flags);
 121 }
 122
 123 static int cpu5wdt_stop(void)
 124 {
 125         unsigned long flags;
 126
 127         spin_lock_irqsave(&cpu5wdt_lock, flags);
 128         if (cpu5wdt_device.running)
 129                 cpu5wdt_device.running = 0;
 130         ticks = cpu5wdt_device.default_ticks;
 131         spin_unlock_irqrestore(&cpu5wdt_lock, flags);
 132         if (verbose)
 133                 pr_crit("stop not possible\n");
 134         return -EIO;
 135 }
 136
 137 /* filesystem operations */
 138
 139 static int cpu5wdt_open(struct inode *inode, struct file *file)
 140 {
 141         if (test_and_set_bit(0, &cpu5wdt_device.inuse))
 142                 return -EBUSY;
 143         return nonseekable_open(inode, file);
 144 }
 145
 146 static int cpu5wdt_release(struct inode *inode, struct file *file)
 147 {
 148         clear_bit(0, &cpu5wdt_device.inuse);
 149         return 0;
 150 }
 151
 152 static long cpu5wdt_ioctl(struct file *file, unsigned int cmd,
 153                                                 unsigned long arg)
 154 {
 155         void __user *argp = (void __user *)arg;
 156         int __user *p = argp;
 157         unsigned int value;
 158         static const struct watchdog_info ident = {
 159                 .options = WDIOF_CARDRESET,
 160                 .identity = "CPU5 WDT",
 161         };
 162
 163         switch (cmd) {
 164         case WDIOC_GETSUPPORT:
 165                 if (copy_to_user(argp, &ident, sizeof(ident)))
 166                         return -EFAULT;
 167                 break;
 168         case WDIOC_GETSTATUS:
 169                 value = inb(port + CPU5WDT_STATUS_REG);
 170                 value = (value >> 2) & 1;
 171                 return put_user(value, p);
 172         case WDIOC_GETBOOTSTATUS:
 173                 return put_user(0, p);
 174         case WDIOC_SETOPTIONS:
 175                 if (get_user(value, p))
 176                         return -EFAULT;
 177                 if (value & WDIOS_ENABLECARD)
 178                         cpu5wdt_start();
 179                 if (value & WDIOS_DISABLECARD)
 180                         cpu5wdt_stop();
 181                 break;
 182         case WDIOC_KEEPALIVE:
 183                 cpu5wdt_reset();
 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,
 192                                                 size_t count, loff_t *ppos)
 193 {
 194         if (!count)
 195                 return -EIO;
 196         cpu5wdt_reset();
 197         return count;
 198 }
 199
 200 static const struct file_operations cpu5wdt_fops = {
 201         .owner          = THIS_MODULE,
 202         .llseek         = no_llseek,
 203         .unlocked_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 cpu5wdt_init(void)
 218 {
 219         unsigned int val;
 220         int err;
 221
 222         if (verbose)
 223                 pr_debug("port=0x%x, verbose=%i\n", port, verbose);
 224
 225         init_completion(&cpu5wdt_device.stop);
 226         cpu5wdt_device.queue = 0;
 227         setup_timer(&cpu5wdt_device.timer, cpu5wdt_trigger, 0);
 228         cpu5wdt_device.default_ticks = ticks;
 229
 230         if (!request_region(port, CPU5WDT_EXTENT, PFX)) {
 231                 pr_err("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                 pr_info("sorry, was my fault\n");
 241
 242         err = misc_register(&cpu5wdt_misc);
 243         if (err < 0) {
 244                 pr_err("misc_register failed\n");
 245                 goto no_misc;
 246         }
 247
 248
 249         pr_info("init success\n");
 250         return 0;
 251
 252 no_misc:
 253         release_region(port, CPU5WDT_EXTENT);
 254 no_port:
 255         return err;
 256 }
 257
 258 static int cpu5wdt_init_module(void)
 259 {
 260         return cpu5wdt_init();
 261 }
 262
 263 static void cpu5wdt_exit(void)
 264 {
 265         if (cpu5wdt_device.queue) {
 266                 cpu5wdt_device.queue = 0;
 267                 wait_for_completion(&cpu5wdt_device.stop);
 268                 del_timer(&cpu5wdt_device.timer);
 269         }
 270
 271         misc_deregister(&cpu5wdt_misc);
 272
 273         release_region(port, CPU5WDT_EXTENT);
 274
 275 }
 276
 277 static void 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
 292 module_param(port, int, 0);
 293 MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
 294
 295 module_param(verbose, int, 0);
 296 MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
 297
 298 module_param(ticks, int, 0);
 299 MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");