1 /* 2 * Watchdog driver for SBC-FITPC2 board 3 * 4 * Author: Denis Turischev <denis@compulab.co.il> 5 * 6 * Adapted from the IXP2000 watchdog driver by Deepak Saxena. 7 * 8 * This file is licensed under the terms of the GNU General Public 9 * License version 2. This program is licensed "as is" without any 10 * warranty of any kind, whether express or implied. 11 */ 12 13 #define pr_fmt(fmt) KBUILD_MODNAME " WATCHDOG: " fmt 14 15 #include <linux/module.h> 16 #include <linux/types.h> 17 #include <linux/miscdevice.h> 18 #include <linux/watchdog.h> 19 #include <linux/ioport.h> 20 #include <linux/delay.h> 21 #include <linux/fs.h> 22 #include <linux/init.h> 23 #include <linux/moduleparam.h> 24 #include <linux/dmi.h> 25 #include <linux/io.h> 26 #include <linux/uaccess.h> 27 28 #include <asm/system.h> 29 30 static int nowayout = WATCHDOG_NOWAYOUT; 31 static unsigned int margin = 60; /* (secs) Default is 1 minute */ 32 static unsigned long wdt_status; 33 static DEFINE_MUTEX(wdt_lock); 34 35 #define WDT_IN_USE 0 36 #define WDT_OK_TO_CLOSE 1 37 38 #define COMMAND_PORT 0x4c 39 #define DATA_PORT 0x48 40 41 #define IFACE_ON_COMMAND 1 42 #define REBOOT_COMMAND 2 43 44 #define WATCHDOG_NAME "SBC-FITPC2 Watchdog" 45 46 static void wdt_send_data(unsigned char command, unsigned char data) 47 { 48 outb(data, DATA_PORT); 49 msleep(200); 50 outb(command, COMMAND_PORT); 51 msleep(100); 52 } 53 54 static void wdt_enable(void) 55 { 56 mutex_lock(&wdt_lock); 57 wdt_send_data(IFACE_ON_COMMAND, 1); 58 wdt_send_data(REBOOT_COMMAND, margin); 59 mutex_unlock(&wdt_lock); 60 } 61 62 static void wdt_disable(void) 63 { 64 mutex_lock(&wdt_lock); 65 wdt_send_data(IFACE_ON_COMMAND, 0); 66 wdt_send_data(REBOOT_COMMAND, 0); 67 mutex_unlock(&wdt_lock); 68 } 69 70 static int fitpc2_wdt_open(struct inode *inode, struct file *file) 71 { 72 if (test_and_set_bit(WDT_IN_USE, &wdt_status)) 73 return -EBUSY; 74 75 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 76 77 wdt_enable(); 78 79 return nonseekable_open(inode, file); 80 } 81 82 static ssize_t fitpc2_wdt_write(struct file *file, const char *data, 83 size_t len, loff_t *ppos) 84 { 85 size_t i; 86 87 if (!len) 88 return 0; 89 90 if (nowayout) { 91 len = 0; 92 goto out; 93 } 94 95 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 96 97 for (i = 0; i != len; i++) { 98 char c; 99 100 if (get_user(c, data + i)) 101 return -EFAULT; 102 103 if (c == 'V') 104 set_bit(WDT_OK_TO_CLOSE, &wdt_status); 105 } 106 107 out: 108 wdt_enable(); 109 110 return len; 111 } 112 113 114 static const struct watchdog_info ident = { 115 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | 116 WDIOF_KEEPALIVEPING, 117 .identity = WATCHDOG_NAME, 118 }; 119 120 121 static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd, 122 unsigned long arg) 123 { 124 int ret = -ENOTTY; 125 int time; 126 127 switch (cmd) { 128 case WDIOC_GETSUPPORT: 129 ret = copy_to_user((struct watchdog_info *)arg, &ident, 130 sizeof(ident)) ? -EFAULT : 0; 131 break; 132 133 case WDIOC_GETSTATUS: 134 ret = put_user(0, (int *)arg); 135 break; 136 137 case WDIOC_GETBOOTSTATUS: 138 ret = put_user(0, (int *)arg); 139 break; 140 141 case WDIOC_KEEPALIVE: 142 wdt_enable(); 143 ret = 0; 144 break; 145 146 case WDIOC_SETTIMEOUT: 147 ret = get_user(time, (int *)arg); 148 if (ret) 149 break; 150 151 if (time < 31 || time > 255) { 152 ret = -EINVAL; 153 break; 154 } 155 156 margin = time; 157 wdt_enable(); 158 /* Fall through */ 159 160 case WDIOC_GETTIMEOUT: 161 ret = put_user(margin, (int *)arg); 162 break; 163 } 164 165 return ret; 166 } 167 168 static int fitpc2_wdt_release(struct inode *inode, struct file *file) 169 { 170 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { 171 wdt_disable(); 172 pr_info("Device disabled\n"); 173 } else { 174 pr_warning("Device closed unexpectedly -" 175 " timer will not stop\n"); 176 wdt_enable(); 177 } 178 179 clear_bit(WDT_IN_USE, &wdt_status); 180 clear_bit(WDT_OK_TO_CLOSE, &wdt_status); 181 182 return 0; 183 } 184 185 186 static const struct file_operations fitpc2_wdt_fops = { 187 .owner = THIS_MODULE, 188 .llseek = no_llseek, 189 .write = fitpc2_wdt_write, 190 .unlocked_ioctl = fitpc2_wdt_ioctl, 191 .open = fitpc2_wdt_open, 192 .release = fitpc2_wdt_release, 193 }; 194 195 static struct miscdevice fitpc2_wdt_miscdev = { 196 .minor = WATCHDOG_MINOR, 197 .name = "watchdog", 198 .fops = &fitpc2_wdt_fops, 199 }; 200 201 static int __init fitpc2_wdt_init(void) 202 { 203 int err; 204 205 if (!strstr(dmi_get_system_info(DMI_BOARD_NAME), "SBC-FITPC2")) 206 return -ENODEV; 207 208 pr_info("%s found\n", dmi_get_system_info(DMI_BOARD_NAME)); 209 210 if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) { 211 pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT); 212 return -EIO; 213 } 214 215 if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) { 216 pr_err("I/O address 0x%04x already in use\n", DATA_PORT); 217 err = -EIO; 218 goto err_data_port; 219 } 220 221 if (margin < 31 || margin > 255) { 222 pr_err("margin must be in range 31 - 255" 223 " seconds, you tried to set %d\n", margin); 224 err = -EINVAL; 225 goto err_margin; 226 } 227 228 err = misc_register(&fitpc2_wdt_miscdev); 229 if (err) { 230 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 231 WATCHDOG_MINOR, err); 232 goto err_margin; 233 } 234 235 return 0; 236 237 err_margin: 238 release_region(DATA_PORT, 1); 239 err_data_port: 240 release_region(COMMAND_PORT, 1); 241 242 return err; 243 } 244 245 static void __exit fitpc2_wdt_exit(void) 246 { 247 misc_deregister(&fitpc2_wdt_miscdev); 248 release_region(DATA_PORT, 1); 249 release_region(COMMAND_PORT, 1); 250 } 251 252 module_init(fitpc2_wdt_init); 253 module_exit(fitpc2_wdt_exit); 254 255 MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>"); 256 MODULE_DESCRIPTION("SBC-FITPC2 Watchdog"); 257 258 module_param(margin, int, 0); 259 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); 260 261 module_param(nowayout, int, 0); 262 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); 263 264 MODULE_LICENSE("GPL"); 265 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 266 267