| 1 | /* |
| 2 | * Advantech Single Board Computer WDT driver |
| 3 | * |
| 4 | * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl> |
| 5 | * |
| 6 | * Based on acquirewdt.c which is based on wdt.c. |
| 7 | * Original copyright messages: |
| 8 | * |
| 9 | * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
| 10 | * All Rights Reserved. |
| 11 | * |
| 12 | * This program is free software; you can redistribute it and/or |
| 13 | * modify it under the terms of the GNU General Public License |
| 14 | * as published by the Free Software Foundation; either version |
| 15 | * 2 of the License, or (at your option) any later version. |
| 16 | * |
| 17 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
| 18 | * warranty for any of this software. This material is provided |
| 19 | * "AS-IS" and at no charge. |
| 20 | * |
| 21 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> |
| 22 | * |
| 23 | * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> |
| 24 | * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT |
| 25 | * |
| 26 | * 16-Oct-2002 Rob Radez <rob@osinvestor.com> |
| 27 | * Clean up ioctls, clean up init + exit, add expect close support, |
| 28 | * add wdt_start and wdt_stop as parameters. |
| 29 | */ |
| 30 | |
| 31 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 32 | |
| 33 | #include <linux/module.h> |
| 34 | #include <linux/moduleparam.h> |
| 35 | #include <linux/types.h> |
| 36 | #include <linux/miscdevice.h> |
| 37 | #include <linux/watchdog.h> |
| 38 | #include <linux/fs.h> |
| 39 | #include <linux/ioport.h> |
| 40 | #include <linux/platform_device.h> |
| 41 | #include <linux/init.h> |
| 42 | #include <linux/io.h> |
| 43 | #include <linux/uaccess.h> |
| 44 | |
| 45 | |
| 46 | #define DRV_NAME "advantechwdt" |
| 47 | #define WATCHDOG_NAME "Advantech WDT" |
| 48 | #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ |
| 49 | |
| 50 | /* the watchdog platform device */ |
| 51 | static struct platform_device *advwdt_platform_device; |
| 52 | static unsigned long advwdt_is_open; |
| 53 | static char adv_expect_close; |
| 54 | |
| 55 | /* |
| 56 | * You must set these - there is no sane way to probe for this board. |
| 57 | * |
| 58 | * To enable or restart, write the timeout value in seconds (1 to 63) |
| 59 | * to I/O port wdt_start. To disable, read I/O port wdt_stop. |
| 60 | * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but |
| 61 | * check your manual (at least the PCA-6159 seems to be different - |
| 62 | * the manual says wdt_stop is 0x43, not 0x443). |
| 63 | * (0x43 is also a write-only control register for the 8254 timer!) |
| 64 | */ |
| 65 | |
| 66 | static int wdt_stop = 0x443; |
| 67 | module_param(wdt_stop, int, 0); |
| 68 | MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)"); |
| 69 | |
| 70 | static int wdt_start = 0x443; |
| 71 | module_param(wdt_start, int, 0); |
| 72 | MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)"); |
| 73 | |
| 74 | static int timeout = WATCHDOG_TIMEOUT; /* in seconds */ |
| 75 | module_param(timeout, int, 0); |
| 76 | MODULE_PARM_DESC(timeout, |
| 77 | "Watchdog timeout in seconds. 1<= timeout <=63, default=" |
| 78 | __MODULE_STRING(WATCHDOG_TIMEOUT) "."); |
| 79 | |
| 80 | static bool nowayout = WATCHDOG_NOWAYOUT; |
| 81 | module_param(nowayout, bool, 0); |
| 82 | MODULE_PARM_DESC(nowayout, |
| 83 | "Watchdog cannot be stopped once started (default=" |
| 84 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 85 | |
| 86 | /* |
| 87 | * Watchdog Operations |
| 88 | */ |
| 89 | |
| 90 | static void advwdt_ping(void) |
| 91 | { |
| 92 | /* Write a watchdog value */ |
| 93 | outb_p(timeout, wdt_start); |
| 94 | } |
| 95 | |
| 96 | static void advwdt_disable(void) |
| 97 | { |
| 98 | inb_p(wdt_stop); |
| 99 | } |
| 100 | |
| 101 | static int advwdt_set_heartbeat(int t) |
| 102 | { |
| 103 | if (t < 1 || t > 63) |
| 104 | return -EINVAL; |
| 105 | timeout = t; |
| 106 | return 0; |
| 107 | } |
| 108 | |
| 109 | /* |
| 110 | * /dev/watchdog handling |
| 111 | */ |
| 112 | |
| 113 | static ssize_t advwdt_write(struct file *file, const char __user *buf, |
| 114 | size_t count, loff_t *ppos) |
| 115 | { |
| 116 | if (count) { |
| 117 | if (!nowayout) { |
| 118 | size_t i; |
| 119 | |
| 120 | adv_expect_close = 0; |
| 121 | |
| 122 | for (i = 0; i != count; i++) { |
| 123 | char c; |
| 124 | if (get_user(c, buf + i)) |
| 125 | return -EFAULT; |
| 126 | if (c == 'V') |
| 127 | adv_expect_close = 42; |
| 128 | } |
| 129 | } |
| 130 | advwdt_ping(); |
| 131 | } |
| 132 | return count; |
| 133 | } |
| 134 | |
| 135 | static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| 136 | { |
| 137 | int new_timeout; |
| 138 | void __user *argp = (void __user *)arg; |
| 139 | int __user *p = argp; |
| 140 | static const struct watchdog_info ident = { |
| 141 | .options = WDIOF_KEEPALIVEPING | |
| 142 | WDIOF_SETTIMEOUT | |
| 143 | WDIOF_MAGICCLOSE, |
| 144 | .firmware_version = 1, |
| 145 | .identity = WATCHDOG_NAME, |
| 146 | }; |
| 147 | |
| 148 | switch (cmd) { |
| 149 | case WDIOC_GETSUPPORT: |
| 150 | if (copy_to_user(argp, &ident, sizeof(ident))) |
| 151 | return -EFAULT; |
| 152 | break; |
| 153 | |
| 154 | case WDIOC_GETSTATUS: |
| 155 | case WDIOC_GETBOOTSTATUS: |
| 156 | return put_user(0, p); |
| 157 | |
| 158 | case WDIOC_SETOPTIONS: |
| 159 | { |
| 160 | int options, retval = -EINVAL; |
| 161 | |
| 162 | if (get_user(options, p)) |
| 163 | return -EFAULT; |
| 164 | if (options & WDIOS_DISABLECARD) { |
| 165 | advwdt_disable(); |
| 166 | retval = 0; |
| 167 | } |
| 168 | if (options & WDIOS_ENABLECARD) { |
| 169 | advwdt_ping(); |
| 170 | retval = 0; |
| 171 | } |
| 172 | return retval; |
| 173 | } |
| 174 | case WDIOC_KEEPALIVE: |
| 175 | advwdt_ping(); |
| 176 | break; |
| 177 | |
| 178 | case WDIOC_SETTIMEOUT: |
| 179 | if (get_user(new_timeout, p)) |
| 180 | return -EFAULT; |
| 181 | if (advwdt_set_heartbeat(new_timeout)) |
| 182 | return -EINVAL; |
| 183 | advwdt_ping(); |
| 184 | /* Fall */ |
| 185 | case WDIOC_GETTIMEOUT: |
| 186 | return put_user(timeout, p); |
| 187 | default: |
| 188 | return -ENOTTY; |
| 189 | } |
| 190 | return 0; |
| 191 | } |
| 192 | |
| 193 | static int advwdt_open(struct inode *inode, struct file *file) |
| 194 | { |
| 195 | if (test_and_set_bit(0, &advwdt_is_open)) |
| 196 | return -EBUSY; |
| 197 | /* |
| 198 | * Activate |
| 199 | */ |
| 200 | |
| 201 | advwdt_ping(); |
| 202 | return nonseekable_open(inode, file); |
| 203 | } |
| 204 | |
| 205 | static int advwdt_close(struct inode *inode, struct file *file) |
| 206 | { |
| 207 | if (adv_expect_close == 42) { |
| 208 | advwdt_disable(); |
| 209 | } else { |
| 210 | pr_crit("Unexpected close, not stopping watchdog!\n"); |
| 211 | advwdt_ping(); |
| 212 | } |
| 213 | clear_bit(0, &advwdt_is_open); |
| 214 | adv_expect_close = 0; |
| 215 | return 0; |
| 216 | } |
| 217 | |
| 218 | /* |
| 219 | * Kernel Interfaces |
| 220 | */ |
| 221 | |
| 222 | static const struct file_operations advwdt_fops = { |
| 223 | .owner = THIS_MODULE, |
| 224 | .llseek = no_llseek, |
| 225 | .write = advwdt_write, |
| 226 | .unlocked_ioctl = advwdt_ioctl, |
| 227 | .open = advwdt_open, |
| 228 | .release = advwdt_close, |
| 229 | }; |
| 230 | |
| 231 | static struct miscdevice advwdt_miscdev = { |
| 232 | .minor = WATCHDOG_MINOR, |
| 233 | .name = "watchdog", |
| 234 | .fops = &advwdt_fops, |
| 235 | }; |
| 236 | |
| 237 | /* |
| 238 | * Init & exit routines |
| 239 | */ |
| 240 | |
| 241 | static int advwdt_probe(struct platform_device *dev) |
| 242 | { |
| 243 | int ret; |
| 244 | |
| 245 | if (wdt_stop != wdt_start) { |
| 246 | if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { |
| 247 | pr_err("I/O address 0x%04x already in use\n", |
| 248 | wdt_stop); |
| 249 | ret = -EIO; |
| 250 | goto out; |
| 251 | } |
| 252 | } |
| 253 | |
| 254 | if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { |
| 255 | pr_err("I/O address 0x%04x already in use\n", wdt_start); |
| 256 | ret = -EIO; |
| 257 | goto unreg_stop; |
| 258 | } |
| 259 | |
| 260 | /* Check that the heartbeat value is within it's range ; |
| 261 | * if not reset to the default */ |
| 262 | if (advwdt_set_heartbeat(timeout)) { |
| 263 | advwdt_set_heartbeat(WATCHDOG_TIMEOUT); |
| 264 | pr_info("timeout value must be 1<=x<=63, using %d\n", timeout); |
| 265 | } |
| 266 | |
| 267 | ret = misc_register(&advwdt_miscdev); |
| 268 | if (ret != 0) { |
| 269 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
| 270 | WATCHDOG_MINOR, ret); |
| 271 | goto unreg_regions; |
| 272 | } |
| 273 | pr_info("initialized. timeout=%d sec (nowayout=%d)\n", |
| 274 | timeout, nowayout); |
| 275 | out: |
| 276 | return ret; |
| 277 | unreg_regions: |
| 278 | release_region(wdt_start, 1); |
| 279 | unreg_stop: |
| 280 | if (wdt_stop != wdt_start) |
| 281 | release_region(wdt_stop, 1); |
| 282 | goto out; |
| 283 | } |
| 284 | |
| 285 | static int advwdt_remove(struct platform_device *dev) |
| 286 | { |
| 287 | misc_deregister(&advwdt_miscdev); |
| 288 | release_region(wdt_start, 1); |
| 289 | if (wdt_stop != wdt_start) |
| 290 | release_region(wdt_stop, 1); |
| 291 | |
| 292 | return 0; |
| 293 | } |
| 294 | |
| 295 | static void advwdt_shutdown(struct platform_device *dev) |
| 296 | { |
| 297 | /* Turn the WDT off if we have a soft shutdown */ |
| 298 | advwdt_disable(); |
| 299 | } |
| 300 | |
| 301 | static struct platform_driver advwdt_driver = { |
| 302 | .probe = advwdt_probe, |
| 303 | .remove = advwdt_remove, |
| 304 | .shutdown = advwdt_shutdown, |
| 305 | .driver = { |
| 306 | .owner = THIS_MODULE, |
| 307 | .name = DRV_NAME, |
| 308 | }, |
| 309 | }; |
| 310 | |
| 311 | static int __init advwdt_init(void) |
| 312 | { |
| 313 | int err; |
| 314 | |
| 315 | pr_info("WDT driver for Advantech single board computer initialising\n"); |
| 316 | |
| 317 | err = platform_driver_register(&advwdt_driver); |
| 318 | if (err) |
| 319 | return err; |
| 320 | |
| 321 | advwdt_platform_device = platform_device_register_simple(DRV_NAME, |
| 322 | -1, NULL, 0); |
| 323 | if (IS_ERR(advwdt_platform_device)) { |
| 324 | err = PTR_ERR(advwdt_platform_device); |
| 325 | goto unreg_platform_driver; |
| 326 | } |
| 327 | |
| 328 | return 0; |
| 329 | |
| 330 | unreg_platform_driver: |
| 331 | platform_driver_unregister(&advwdt_driver); |
| 332 | return err; |
| 333 | } |
| 334 | |
| 335 | static void __exit advwdt_exit(void) |
| 336 | { |
| 337 | platform_device_unregister(advwdt_platform_device); |
| 338 | platform_driver_unregister(&advwdt_driver); |
| 339 | pr_info("Watchdog Module Unloaded\n"); |
| 340 | } |
| 341 | |
| 342 | module_init(advwdt_init); |
| 343 | module_exit(advwdt_exit); |
| 344 | |
| 345 | MODULE_LICENSE("GPL"); |
| 346 | MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>"); |
| 347 | MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver"); |
| 348 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |