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/init.h>
  31 #include <linux/ioport.h>
  32 #include <linux/timer.h>
  33 #include <linux/completion.h>
  34 #include <linux/jiffies.h>
  35 #include <linux/io.h>
  36 #include <linux/uaccess.h>
  37 #include <linux/watchdog.h>
  38
  39 /* adjustable parameters */
  40
  41 static int verbose;
  42 static int port = 0x91;
  43 static int ticks = 10000;
  44 static DEFINE_SPINLOCK(cpu5wdt_lock);
  45
  46 #define PFX                     "cpu5wdt: "
  47
  48 #define CPU5WDT_EXTENT          0x0A
  49
  50 #define CPU5WDT_STATUS_REG      0x00
  51 #define CPU5WDT_TIME_A_REG      0x02
  52 #define CPU5WDT_TIME_B_REG      0x03
  53 #define CPU5WDT_MODE_REG        0x04
  54 #define CPU5WDT_TRIGGER_REG     0x07
  55 #define CPU5WDT_ENABLE_REG      0x08
  56 #define CPU5WDT_RESET_REG       0x09
  57
  58 #define CPU5WDT_INTERVAL        (HZ/10+1)
  59
  60 /* some device data */
  61
  62 static struct {
  63         struct completion stop;
  64         int running;
  65         struct timer_list timer;
  66         int queue;
  67         int default_ticks;
  68         unsigned long inuse;
  69 } cpu5wdt_device;
  70
  71 /* generic helper functions */
  72
  73 static void cpu5wdt_trigger(unsigned long unused)
  74 {
  75         if (verbose > 2)
  76                 pr_debug("trigger at %i ticks\n", ticks);
  77
  78         if (cpu5wdt_device.running)
  79                 ticks--;
  80
  81         spin_lock(&cpu5wdt_lock);
  82         /* keep watchdog alive */
  83         outb(1, port + CPU5WDT_TRIGGER_REG);
  84
  85         /* requeue?? */
  86         if (cpu5wdt_device.queue && ticks)
  87                 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
  88         else {
  89                 /* ticks doesn't matter anyway */
  90                 complete(&cpu5wdt_device.stop);
  91         }
  92         spin_unlock(&cpu5wdt_lock);
  93
  94 }
  95
  96 static void cpu5wdt_reset(void)
  97 {
  98         ticks = cpu5wdt_device.default_ticks;
  99
 100         if (verbose)
 101                 pr_debug("reset (%i ticks)\n", (int) ticks);
 102
 103 }
 104
 105 static void cpu5wdt_start(void)
 106 {
 107         unsigned long flags;
 108
 109         spin_lock_irqsave(&cpu5wdt_lock, flags);
 110         if (!cpu5wdt_device.queue) {
 111                 cpu5wdt_device.queue = 1;
 112                 outb(0, port + CPU5WDT_TIME_A_REG);
 113                 outb(0, port + CPU5WDT_TIME_B_REG);
 114                 outb(1, port + CPU5WDT_MODE_REG);
 115                 outb(0, port + CPU5WDT_RESET_REG);
 116                 outb(0, port + CPU5WDT_ENABLE_REG);
 117                 mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
 118         }
 119         /* if process dies, counter is not decremented */
 120         cpu5wdt_device.running++;
 121         spin_unlock_irqrestore(&cpu5wdt_lock, flags);
 122 }
 123
 124 static int cpu5wdt_stop(void)
 125 {
 126         unsigned long flags;
 127
 128         spin_lock_irqsave(&cpu5wdt_lock, flags);
 129         if (cpu5wdt_device.running)
 130                 cpu5wdt_device.running = 0;
 131         ticks = cpu5wdt_device.default_ticks;
 132         spin_unlock_irqrestore(&cpu5wdt_lock, flags);
 133         if (verbose)
 134                 pr_crit("stop not possible\n");
 135         return -EIO;
 136 }
 137
 138 /* filesystem operations */
 139
 140 static int cpu5wdt_open(struct inode *inode, struct file *file)
 141 {
 142         if (test_and_set_bit(0, &cpu5wdt_device.inuse))
 143                 return -EBUSY;
 144         return nonseekable_open(inode, file);
 145 }
 146
 147 static int cpu5wdt_release(struct inode *inode, struct file *file)
 148 {
 149         clear_bit(0, &cpu5wdt_device.inuse);
 150         return 0;
 151 }
 152
 153 static long cpu5wdt_ioctl(struct file *file, unsigned int cmd,
 154                                                 unsigned long arg)
 155 {
 156         void __user *argp = (void __user *)arg;
 157         int __user *p = argp;
 158         unsigned int value;
 159         static const struct watchdog_info ident = {
 160                 .options = WDIOF_CARDRESET,
 161                 .identity = "CPU5 WDT",
 162         };
 163
 164         switch (cmd) {
 165         case WDIOC_GETSUPPORT:
 166                 if (copy_to_user(argp, &ident, sizeof(ident)))
 167                         return -EFAULT;
 168                 break;
 169         case WDIOC_GETSTATUS:
 170                 value = inb(port + CPU5WDT_STATUS_REG);
 171                 value = (value >> 2) & 1;
 172                 return put_user(value, p);
 173         case WDIOC_GETBOOTSTATUS:
 174                 return put_user(0, p);
 175         case WDIOC_SETOPTIONS:
 176                 if (get_user(value, p))
 177                         return -EFAULT;
 178                 if (value & WDIOS_ENABLECARD)
 179                         cpu5wdt_start();
 180                 if (value & WDIOS_DISABLECARD)
 181                         cpu5wdt_stop();
 182                 break;
 183         case WDIOC_KEEPALIVE:
 184                 cpu5wdt_reset();
 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,
 193                                                 size_t count, loff_t *ppos)
 194 {
 195         if (!count)
 196                 return -EIO;
 197         cpu5wdt_reset();
 198         return count;
 199 }
 200
 201 static const struct file_operations cpu5wdt_fops = {
 202         .owner          = THIS_MODULE,
 203         .llseek         = no_llseek,
 204         .unlocked_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 cpu5wdt_init(void)
 219 {
 220         unsigned int val;
 221         int err;
 222
 223         if (verbose)
 224                 pr_debug("port=0x%x, verbose=%i\n", port, verbose);
 225
 226         init_completion(&cpu5wdt_device.stop);
 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                 pr_err("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                 pr_info("sorry, was my fault\n");
 242
 243         err = misc_register(&cpu5wdt_misc);
 244         if (err < 0) {
 245                 pr_err("misc_register failed\n");
 246                 goto no_misc;
 247         }
 248
 249
 250         pr_info("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 cpu5wdt_init_module(void)
 260 {
 261         return cpu5wdt_init();
 262 }
 263
 264 static void cpu5wdt_exit(void)
 265 {
 266         if (cpu5wdt_device.queue) {
 267                 cpu5wdt_device.queue = 0;
 268                 wait_for_completion(&cpu5wdt_device.stop);
 269                 del_timer(&cpu5wdt_device.timer);
 270         }
 271
 272         misc_deregister(&cpu5wdt_misc);
 273
 274         release_region(port, CPU5WDT_EXTENT);
 275
 276 }
 277
 278 static void cpu5wdt_exit_module(void)
 279 {
 280         cpu5wdt_exit();
 281 }
 282
 283 /* module entry points */
 284
 285 module_init(cpu5wdt_init_module);
 286 module_exit(cpu5wdt_exit_module);
 287
 288 MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
 289 MODULE_DESCRIPTION("sma cpu5 watchdog driver");
 290 MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
 291 MODULE_LICENSE("GPL");
 292 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 293
 294 module_param(port, int, 0);
 295 MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
 296
 297 module_param(verbose, int, 0);
 298 MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
 299
 300 module_param(ticks, int, 0);
 301 MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");