1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Advantech Single Board Computer WDT driver 4 * 5 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl> 6 * 7 * Based on acquirewdt.c which is based on wdt.c. 8 * Original copyright messages: 9 * 10 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, 11 * All Rights Reserved. 12 * 13 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide 14 * warranty for any of this software. This material is provided 15 * "AS-IS" and at no charge. 16 * 17 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> 18 * 19 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> 20 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT 21 * 22 * 16-Oct-2002 Rob Radez <rob@osinvestor.com> 23 * Clean up ioctls, clean up init + exit, add expect close support, 24 * add wdt_start and wdt_stop as parameters. 25 */ 26 27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 28 29 #include <linux/module.h> 30 #include <linux/moduleparam.h> 31 #include <linux/types.h> 32 #include <linux/miscdevice.h> 33 #include <linux/watchdog.h> 34 #include <linux/fs.h> 35 #include <linux/ioport.h> 36 #include <linux/platform_device.h> 37 #include <linux/init.h> 38 #include <linux/io.h> 39 #include <linux/uaccess.h> 40 41 42 #define DRV_NAME "advantechwdt" 43 #define WATCHDOG_NAME "Advantech WDT" 44 #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ 45 46 /* the watchdog platform device */ 47 static struct platform_device *advwdt_platform_device; 48 static unsigned long advwdt_is_open; 49 static char adv_expect_close; 50 51 /* 52 * You must set these - there is no sane way to probe for this board. 53 * 54 * To enable or restart, write the timeout value in seconds (1 to 63) 55 * to I/O port wdt_start. To disable, read I/O port wdt_stop. 56 * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but 57 * check your manual (at least the PCA-6159 seems to be different - 58 * the manual says wdt_stop is 0x43, not 0x443). 59 * (0x43 is also a write-only control register for the 8254 timer!) 60 */ 61 62 static int wdt_stop = 0x443; 63 module_param(wdt_stop, int, 0); 64 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)"); 65 66 static int wdt_start = 0x443; 67 module_param(wdt_start, int, 0); 68 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)"); 69 70 static int timeout = WATCHDOG_TIMEOUT; /* in seconds */ 71 module_param(timeout, int, 0); 72 MODULE_PARM_DESC(timeout, 73 "Watchdog timeout in seconds. 1<= timeout <=63, default=" 74 __MODULE_STRING(WATCHDOG_TIMEOUT) "."); 75 76 static bool nowayout = WATCHDOG_NOWAYOUT; 77 module_param(nowayout, bool, 0); 78 MODULE_PARM_DESC(nowayout, 79 "Watchdog cannot be stopped once started (default=" 80 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 81 82 /* 83 * Watchdog Operations 84 */ 85 86 static void advwdt_ping(void) 87 { 88 /* Write a watchdog value */ 89 outb_p(timeout, wdt_start); 90 } 91 92 static void advwdt_disable(void) 93 { 94 inb_p(wdt_stop); 95 } 96 97 static int advwdt_set_heartbeat(int t) 98 { 99 if (t < 1 || t > 63) 100 return -EINVAL; 101 timeout = t; 102 return 0; 103 } 104 105 /* 106 * /dev/watchdog handling 107 */ 108 109 static ssize_t advwdt_write(struct file *file, const char __user *buf, 110 size_t count, loff_t *ppos) 111 { 112 if (count) { 113 if (!nowayout) { 114 size_t i; 115 116 adv_expect_close = 0; 117 118 for (i = 0; i != count; i++) { 119 char c; 120 if (get_user(c, buf + i)) 121 return -EFAULT; 122 if (c == 'V') 123 adv_expect_close = 42; 124 } 125 } 126 advwdt_ping(); 127 } 128 return count; 129 } 130 131 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 132 { 133 int new_timeout; 134 void __user *argp = (void __user *)arg; 135 int __user *p = argp; 136 static const struct watchdog_info ident = { 137 .options = WDIOF_KEEPALIVEPING | 138 WDIOF_SETTIMEOUT | 139 WDIOF_MAGICCLOSE, 140 .firmware_version = 1, 141 .identity = WATCHDOG_NAME, 142 }; 143 144 switch (cmd) { 145 case WDIOC_GETSUPPORT: 146 if (copy_to_user(argp, &ident, sizeof(ident))) 147 return -EFAULT; 148 break; 149 150 case WDIOC_GETSTATUS: 151 case WDIOC_GETBOOTSTATUS: 152 return put_user(0, p); 153 154 case WDIOC_SETOPTIONS: 155 { 156 int options, retval = -EINVAL; 157 158 if (get_user(options, p)) 159 return -EFAULT; 160 if (options & WDIOS_DISABLECARD) { 161 advwdt_disable(); 162 retval = 0; 163 } 164 if (options & WDIOS_ENABLECARD) { 165 advwdt_ping(); 166 retval = 0; 167 } 168 return retval; 169 } 170 case WDIOC_KEEPALIVE: 171 advwdt_ping(); 172 break; 173 174 case WDIOC_SETTIMEOUT: 175 if (get_user(new_timeout, p)) 176 return -EFAULT; 177 if (advwdt_set_heartbeat(new_timeout)) 178 return -EINVAL; 179 advwdt_ping(); 180 fallthrough; 181 case WDIOC_GETTIMEOUT: 182 return put_user(timeout, p); 183 default: 184 return -ENOTTY; 185 } 186 return 0; 187 } 188 189 static int advwdt_open(struct inode *inode, struct file *file) 190 { 191 if (test_and_set_bit(0, &advwdt_is_open)) 192 return -EBUSY; 193 /* 194 * Activate 195 */ 196 197 advwdt_ping(); 198 return stream_open(inode, file); 199 } 200 201 static int advwdt_close(struct inode *inode, struct file *file) 202 { 203 if (adv_expect_close == 42) { 204 advwdt_disable(); 205 } else { 206 pr_crit("Unexpected close, not stopping watchdog!\n"); 207 advwdt_ping(); 208 } 209 clear_bit(0, &advwdt_is_open); 210 adv_expect_close = 0; 211 return 0; 212 } 213 214 /* 215 * Kernel Interfaces 216 */ 217 218 static const struct file_operations advwdt_fops = { 219 .owner = THIS_MODULE, 220 .llseek = no_llseek, 221 .write = advwdt_write, 222 .unlocked_ioctl = advwdt_ioctl, 223 .compat_ioctl = compat_ptr_ioctl, 224 .open = advwdt_open, 225 .release = advwdt_close, 226 }; 227 228 static struct miscdevice advwdt_miscdev = { 229 .minor = WATCHDOG_MINOR, 230 .name = "watchdog", 231 .fops = &advwdt_fops, 232 }; 233 234 /* 235 * Init & exit routines 236 */ 237 238 static int __init advwdt_probe(struct platform_device *dev) 239 { 240 int ret; 241 242 if (wdt_stop != wdt_start) { 243 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { 244 pr_err("I/O address 0x%04x already in use\n", 245 wdt_stop); 246 ret = -EIO; 247 goto out; 248 } 249 } 250 251 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { 252 pr_err("I/O address 0x%04x already in use\n", wdt_start); 253 ret = -EIO; 254 goto unreg_stop; 255 } 256 257 /* Check that the heartbeat value is within it's range ; 258 * if not reset to the default */ 259 if (advwdt_set_heartbeat(timeout)) { 260 advwdt_set_heartbeat(WATCHDOG_TIMEOUT); 261 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout); 262 } 263 264 ret = misc_register(&advwdt_miscdev); 265 if (ret != 0) { 266 pr_err("cannot register miscdev on minor=%d (err=%d)\n", 267 WATCHDOG_MINOR, ret); 268 goto unreg_regions; 269 } 270 pr_info("initialized. timeout=%d sec (nowayout=%d)\n", 271 timeout, nowayout); 272 out: 273 return ret; 274 unreg_regions: 275 release_region(wdt_start, 1); 276 unreg_stop: 277 if (wdt_stop != wdt_start) 278 release_region(wdt_stop, 1); 279 goto out; 280 } 281 282 static int advwdt_remove(struct platform_device *dev) 283 { 284 misc_deregister(&advwdt_miscdev); 285 release_region(wdt_start, 1); 286 if (wdt_stop != wdt_start) 287 release_region(wdt_stop, 1); 288 289 return 0; 290 } 291 292 static void advwdt_shutdown(struct platform_device *dev) 293 { 294 /* Turn the WDT off if we have a soft shutdown */ 295 advwdt_disable(); 296 } 297 298 static struct platform_driver advwdt_driver = { 299 .remove = advwdt_remove, 300 .shutdown = advwdt_shutdown, 301 .driver = { 302 .name = DRV_NAME, 303 }, 304 }; 305 306 static int __init advwdt_init(void) 307 { 308 int err; 309 310 pr_info("WDT driver for Advantech single board computer initialising\n"); 311 312 advwdt_platform_device = platform_device_register_simple(DRV_NAME, 313 -1, NULL, 0); 314 if (IS_ERR(advwdt_platform_device)) 315 return PTR_ERR(advwdt_platform_device); 316 317 err = platform_driver_probe(&advwdt_driver, advwdt_probe); 318 if (err) 319 goto unreg_platform_device; 320 321 return 0; 322 323 unreg_platform_device: 324 platform_device_unregister(advwdt_platform_device); 325 return err; 326 } 327 328 static void __exit advwdt_exit(void) 329 { 330 platform_device_unregister(advwdt_platform_device); 331 platform_driver_unregister(&advwdt_driver); 332 pr_info("Watchdog Module Unloaded\n"); 333 } 334 335 module_init(advwdt_init); 336 module_exit(advwdt_exit); 337 338 MODULE_LICENSE("GPL"); 339 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>"); 340 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver"); 341