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 40static int verbose = 0; 41static int port = 0x91; 42static 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 60static 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 71static 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 92static 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 101static 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 116static 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 131static 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 139static int cpu5wdt_release(struct inode *inode, struct file *file) 140{ 141 clear_bit(0, &cpu5wdt_device.inuse); 142 return 0; 143} 144 145static 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_GETSUPPORT: 166 if ( copy_to_user(argp, &ident, sizeof(ident)) ) 167 return -EFAULT; 168 break; 169 case WDIOC_SETOPTIONS: 170 if ( copy_from_user(&value, argp, sizeof(int)) ) 171 return -EFAULT; 172 switch(value) { 173 case WDIOS_ENABLECARD: 174 cpu5wdt_start(); 175 break; 176 case WDIOS_DISABLECARD: 177 return cpu5wdt_stop(); 178 default: 179 return -EINVAL; 180 } 181 break; 182 default: 183 return -ENOTTY; 184 } 185 return 0; 186} 187 188static ssize_t cpu5wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 189{ 190 if ( !count ) 191 return -EIO; 192 193 cpu5wdt_reset(); 194 195 return count; 196} 197 198static const struct file_operations cpu5wdt_fops = { 199 .owner = THIS_MODULE, 200 .llseek = no_llseek, 201 .ioctl = cpu5wdt_ioctl, 202 .open = cpu5wdt_open, 203 .write = cpu5wdt_write, 204 .release = cpu5wdt_release, 205}; 206 207static struct miscdevice cpu5wdt_misc = { 208 .minor = WATCHDOG_MINOR, 209 .name = "watchdog", 210 .fops = &cpu5wdt_fops, 211}; 212 213/* init/exit function */ 214 215static int __devinit cpu5wdt_init(void) 216{ 217 unsigned int val; 218 int err; 219 220 if ( verbose ) 221 printk(KERN_DEBUG PFX "port=0x%x, verbose=%i\n", port, verbose); 222 223 if ( !request_region(port, CPU5WDT_EXTENT, PFX) ) { 224 printk(KERN_ERR PFX "request_region failed\n"); 225 err = -EBUSY; 226 goto no_port; 227 } 228 229 if ( (err = misc_register(&cpu5wdt_misc)) < 0 ) { 230 printk(KERN_ERR PFX "misc_register failed\n"); 231 goto no_misc; 232 } 233 234 /* watchdog reboot? */ 235 val = inb(port + CPU5WDT_STATUS_REG); 236 val = (val >> 2) & 1; 237 if ( !val ) 238 printk(KERN_INFO PFX "sorry, was my fault\n"); 239 240 init_completion(&cpu5wdt_device.stop); 241 cpu5wdt_device.queue = 0; 242 243 clear_bit(0, &cpu5wdt_device.inuse); 244 245 setup_timer(&cpu5wdt_device.timer, cpu5wdt_trigger, 0); 246 247 cpu5wdt_device.default_ticks = ticks; 248 249 printk(KERN_INFO PFX "init success\n"); 250 251 return 0; 252 253no_misc: 254 release_region(port, CPU5WDT_EXTENT); 255no_port: 256 return err; 257} 258 259static int __devinit cpu5wdt_init_module(void) 260{ 261 return cpu5wdt_init(); 262} 263 264static 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 277static void __devexit cpu5wdt_exit_module(void) 278{ 279 cpu5wdt_exit(); 280} 281 282/* module entry points */ 283 284module_init(cpu5wdt_init_module); 285module_exit(cpu5wdt_exit_module); 286 287MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>"); 288MODULE_DESCRIPTION("sma cpu5 watchdog driver"); 289MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog"); 290MODULE_LICENSE("GPL"); 291MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 292 293module_param(port, int, 0); 294MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91"); 295 296module_param(verbose, int, 0); 297MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)"); 298 299module_param(ticks, int, 0); 300MODULE_PARM_DESC(ticks, "count down ticks, default is 10000"); 301