1 /* 2 * National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver 3 * (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>, 4 * All Rights Reserved. 5 * Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively. 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * The author(s) of this software shall not be held liable for damages 13 * of any nature resulting due to the use of this software. This 14 * software is provided AS-IS with no warranties. 15 * 16 * Changelog: 17 * 20020220 Zwane Mwaikambo Code based on datasheet, no hardware. 18 * 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik 19 * and Alan Cox. 20 * 20020222 Zwane Mwaikambo Added probing. 21 * 20020225 Zwane Mwaikambo Added ISAPNP support. 22 * 20020412 Rob Radez Broke out start/stop functions 23 * <rob@osinvestor.com> Return proper status instead of 24 * temperature warning 25 * Add WDIOC_GETBOOTSTATUS and 26 * WDIOC_SETOPTIONS ioctls 27 * Fix CONFIG_WATCHDOG_NOWAYOUT 28 * 20020530 Joel Becker Add Matt Domsch's nowayout module 29 * option 30 * 20030116 Adam Belay Updated to the latest pnp code 31 * 32 */ 33 34 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 35 36 #include <linux/module.h> 37 #include <linux/moduleparam.h> 38 #include <linux/miscdevice.h> 39 #include <linux/watchdog.h> 40 #include <linux/ioport.h> 41 #include <linux/spinlock.h> 42 #include <linux/notifier.h> 43 #include <linux/reboot.h> 44 #include <linux/init.h> 45 #include <linux/pnp.h> 46 #include <linux/fs.h> 47 #include <linux/semaphore.h> 48 #include <linux/io.h> 49 #include <linux/uaccess.h> 50 51 #define SC1200_MODULE_VER "build 20020303" 52 #define SC1200_MODULE_NAME "sc1200wdt" 53 54 #define MAX_TIMEOUT 255 /* 255 minutes */ 55 #define PMIR (io) /* Power Management Index Register */ 56 #define PMDR (io+1) /* Power Management Data Register */ 57 58 /* Data Register indexes */ 59 #define FER1 0x00 /* Function enable register 1 */ 60 #define FER2 0x01 /* Function enable register 2 */ 61 #define PMC1 0x02 /* Power Management Ctrl 1 */ 62 #define PMC2 0x03 /* Power Management Ctrl 2 */ 63 #define PMC3 0x04 /* Power Management Ctrl 3 */ 64 #define WDTO 0x05 /* Watchdog timeout register */ 65 #define WDCF 0x06 /* Watchdog config register */ 66 #define WDST 0x07 /* Watchdog status register */ 67 68 /* WDCF bitfields - which devices assert WDO */ 69 #define KBC_IRQ 0x01 /* Keyboard Controller */ 70 #define MSE_IRQ 0x02 /* Mouse */ 71 #define UART1_IRQ 0x03 /* Serial0 */ 72 #define UART2_IRQ 0x04 /* Serial1 */ 73 /* 5 -7 are reserved */ 74 75 static int timeout = 1; 76 static int io = -1; 77 static int io_len = 2; /* for non plug and play */ 78 static unsigned long open_flag; 79 static char expect_close; 80 static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */ 81 82 #if defined CONFIG_PNP 83 static int isapnp = 1; 84 static struct pnp_dev *wdt_dev; 85 86 module_param(isapnp, int, 0); 87 MODULE_PARM_DESC(isapnp, 88 "When set to 0 driver ISA PnP support will be disabled"); 89 #endif 90 91 module_param(io, int, 0); 92 MODULE_PARM_DESC(io, "io port"); 93 module_param(timeout, int, 0); 94 MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1"); 95 96 static bool nowayout = WATCHDOG_NOWAYOUT; 97 module_param(nowayout, bool, 0); 98 MODULE_PARM_DESC(nowayout, 99 "Watchdog cannot be stopped once started (default=" 100 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 101 102 103 104 /* Read from Data Register */ 105 static inline void __sc1200wdt_read_data(unsigned char index, 106 unsigned char *data) 107 { 108 outb_p(index, PMIR); 109 *data = inb(PMDR); 110 } 111 112 static void sc1200wdt_read_data(unsigned char index, unsigned char *data) 113 { 114 spin_lock(&sc1200wdt_lock); 115 __sc1200wdt_read_data(index, data); 116 spin_unlock(&sc1200wdt_lock); 117 } 118 119 /* Write to Data Register */ 120 static inline void __sc1200wdt_write_data(unsigned char index, 121 unsigned char data) 122 { 123 outb_p(index, PMIR); 124 outb(data, PMDR); 125 } 126 127 static inline void sc1200wdt_write_data(unsigned char index, 128 unsigned char data) 129 { 130 spin_lock(&sc1200wdt_lock); 131 __sc1200wdt_write_data(index, data); 132 spin_unlock(&sc1200wdt_lock); 133 } 134 135 136 static void sc1200wdt_start(void) 137 { 138 unsigned char reg; 139 spin_lock(&sc1200wdt_lock); 140 141 __sc1200wdt_read_data(WDCF, ®); 142 /* assert WDO when any of the following interrupts are triggered too */ 143 reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ); 144 __sc1200wdt_write_data(WDCF, reg); 145 /* set the timeout and get the ball rolling */ 146 __sc1200wdt_write_data(WDTO, timeout); 147 148 spin_unlock(&sc1200wdt_lock); 149 } 150 151 static void sc1200wdt_stop(void) 152 { 153 sc1200wdt_write_data(WDTO, 0); 154 } 155 156 /* This returns the status of the WDO signal, inactive high. */ 157 static inline int sc1200wdt_status(void) 158 { 159 unsigned char ret; 160 161 sc1200wdt_read_data(WDST, &ret); 162 /* If the bit is inactive, the watchdog is enabled, so return 163 * KEEPALIVEPING which is a bit of a kludge because there's nothing 164 * else for enabled/disabled status 165 */ 166 return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING; 167 } 168 169 static int sc1200wdt_open(struct inode *inode, struct file *file) 170 { 171 /* allow one at a time */ 172 if (test_and_set_bit(0, &open_flag)) 173 return -EBUSY; 174 175 if (timeout > MAX_TIMEOUT) 176 timeout = MAX_TIMEOUT; 177 178 sc1200wdt_start(); 179 pr_info("Watchdog enabled, timeout = %d min(s)", timeout); 180 181 return nonseekable_open(inode, file); 182 } 183 184 185 static long sc1200wdt_ioctl(struct file *file, unsigned int cmd, 186 unsigned long arg) 187 { 188 int new_timeout; 189 void __user *argp = (void __user *)arg; 190 int __user *p = argp; 191 static const struct watchdog_info ident = { 192 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | 193 WDIOF_MAGICCLOSE, 194 .firmware_version = 0, 195 .identity = "PC87307/PC97307", 196 }; 197 198 switch (cmd) { 199 case WDIOC_GETSUPPORT: 200 if (copy_to_user(argp, &ident, sizeof(ident))) 201 return -EFAULT; 202 return 0; 203 204 case WDIOC_GETSTATUS: 205 return put_user(sc1200wdt_status(), p); 206 207 case WDIOC_GETBOOTSTATUS: 208 return put_user(0, p); 209 210 case WDIOC_SETOPTIONS: 211 { 212 int options, retval = -EINVAL; 213 214 if (get_user(options, p)) 215 return -EFAULT; 216 217 if (options & WDIOS_DISABLECARD) { 218 sc1200wdt_stop(); 219 retval = 0; 220 } 221 222 if (options & WDIOS_ENABLECARD) { 223 sc1200wdt_start(); 224 retval = 0; 225 } 226 227 return retval; 228 } 229 case WDIOC_KEEPALIVE: 230 sc1200wdt_write_data(WDTO, timeout); 231 return 0; 232 233 case WDIOC_SETTIMEOUT: 234 if (get_user(new_timeout, p)) 235 return -EFAULT; 236 /* the API states this is given in secs */ 237 new_timeout /= 60; 238 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) 239 return -EINVAL; 240 timeout = new_timeout; 241 sc1200wdt_write_data(WDTO, timeout); 242 /* fall through and return the new timeout */ 243 244 case WDIOC_GETTIMEOUT: 245 return put_user(timeout * 60, p); 246 247 default: 248 return -ENOTTY; 249 } 250 } 251 252 253 static int sc1200wdt_release(struct inode *inode, struct file *file) 254 { 255 if (expect_close == 42) { 256 sc1200wdt_stop(); 257 pr_info("Watchdog disabled\n"); 258 } else { 259 sc1200wdt_write_data(WDTO, timeout); 260 pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout); 261 } 262 clear_bit(0, &open_flag); 263 expect_close = 0; 264 265 return 0; 266 } 267 268 269 static ssize_t sc1200wdt_write(struct file *file, const char __user *data, 270 size_t len, loff_t *ppos) 271 { 272 if (len) { 273 if (!nowayout) { 274 size_t i; 275 276 expect_close = 0; 277 278 for (i = 0; i != len; i++) { 279 char c; 280 281 if (get_user(c, data + i)) 282 return -EFAULT; 283 if (c == 'V') 284 expect_close = 42; 285 } 286 } 287 288 sc1200wdt_write_data(WDTO, timeout); 289 return len; 290 } 291 292 return 0; 293 } 294 295 296 static int sc1200wdt_notify_sys(struct notifier_block *this, 297 unsigned long code, void *unused) 298 { 299 if (code == SYS_DOWN || code == SYS_HALT) 300 sc1200wdt_stop(); 301 302 return NOTIFY_DONE; 303 } 304 305 306 static struct notifier_block sc1200wdt_notifier = { 307 .notifier_call = sc1200wdt_notify_sys, 308 }; 309 310 static const struct file_operations sc1200wdt_fops = { 311 .owner = THIS_MODULE, 312 .llseek = no_llseek, 313 .write = sc1200wdt_write, 314 .unlocked_ioctl = sc1200wdt_ioctl, 315 .open = sc1200wdt_open, 316 .release = sc1200wdt_release, 317 }; 318 319 static struct miscdevice sc1200wdt_miscdev = { 320 .minor = WATCHDOG_MINOR, 321 .name = "watchdog", 322 .fops = &sc1200wdt_fops, 323 }; 324 325 326 static int __init sc1200wdt_probe(void) 327 { 328 /* The probe works by reading the PMC3 register's default value of 0x0e 329 * there is one caveat, if the device disables the parallel port or any 330 * of the UARTs we won't be able to detect it. 331 * NB. This could be done with accuracy by reading the SID registers, 332 * but we don't have access to those io regions. 333 */ 334 335 unsigned char reg; 336 337 sc1200wdt_read_data(PMC3, ®); 338 reg &= 0x0f; /* we don't want the UART busy bits */ 339 return (reg == 0x0e) ? 0 : -ENODEV; 340 } 341 342 343 #if defined CONFIG_PNP 344 345 static struct pnp_device_id scl200wdt_pnp_devices[] = { 346 /* National Semiconductor PC87307/PC97307 watchdog component */ 347 {.id = "NSC0800", .driver_data = 0}, 348 {.id = ""}, 349 }; 350 351 static int scl200wdt_pnp_probe(struct pnp_dev *dev, 352 const struct pnp_device_id *dev_id) 353 { 354 /* this driver only supports one card at a time */ 355 if (wdt_dev || !isapnp) 356 return -EBUSY; 357 358 wdt_dev = dev; 359 io = pnp_port_start(wdt_dev, 0); 360 io_len = pnp_port_len(wdt_dev, 0); 361 362 if (!request_region(io, io_len, SC1200_MODULE_NAME)) { 363 pr_err("Unable to register IO port %#x\n", io); 364 return -EBUSY; 365 } 366 367 pr_info("PnP device found at io port %#x/%d\n", io, io_len); 368 return 0; 369 } 370 371 static void scl200wdt_pnp_remove(struct pnp_dev *dev) 372 { 373 if (wdt_dev) { 374 release_region(io, io_len); 375 wdt_dev = NULL; 376 } 377 } 378 379 static struct pnp_driver scl200wdt_pnp_driver = { 380 .name = "scl200wdt", 381 .id_table = scl200wdt_pnp_devices, 382 .probe = scl200wdt_pnp_probe, 383 .remove = scl200wdt_pnp_remove, 384 }; 385 386 #endif /* CONFIG_PNP */ 387 388 389 static int __init sc1200wdt_init(void) 390 { 391 int ret; 392 393 pr_info("%s\n", SC1200_MODULE_VER); 394 395 #if defined CONFIG_PNP 396 if (isapnp) { 397 ret = pnp_register_driver(&scl200wdt_pnp_driver); 398 if (ret) 399 goto out_clean; 400 } 401 #endif 402 403 if (io == -1) { 404 pr_err("io parameter must be specified\n"); 405 ret = -EINVAL; 406 goto out_pnp; 407 } 408 409 #if defined CONFIG_PNP 410 /* now that the user has specified an IO port and we haven't detected 411 * any devices, disable pnp support */ 412 if (isapnp) 413 pnp_unregister_driver(&scl200wdt_pnp_driver); 414 isapnp = 0; 415 #endif 416 417 if (!request_region(io, io_len, SC1200_MODULE_NAME)) { 418 pr_err("Unable to register IO port %#x\n", io); 419 ret = -EBUSY; 420 goto out_pnp; 421 } 422 423 ret = sc1200wdt_probe(); 424 if (ret) 425 goto out_io; 426 427 ret = register_reboot_notifier(&sc1200wdt_notifier); 428 if (ret) { 429 pr_err("Unable to register reboot notifier err = %d\n", ret); 430 goto out_io; 431 } 432 433 ret = misc_register(&sc1200wdt_miscdev); 434 if (ret) { 435 pr_err("Unable to register miscdev on minor %d\n", 436 WATCHDOG_MINOR); 437 goto out_rbt; 438 } 439 440 /* ret = 0 */ 441 442 out_clean: 443 return ret; 444 445 out_rbt: 446 unregister_reboot_notifier(&sc1200wdt_notifier); 447 448 out_io: 449 release_region(io, io_len); 450 451 out_pnp: 452 #if defined CONFIG_PNP 453 if (isapnp) 454 pnp_unregister_driver(&scl200wdt_pnp_driver); 455 #endif 456 goto out_clean; 457 } 458 459 460 static void __exit sc1200wdt_exit(void) 461 { 462 misc_deregister(&sc1200wdt_miscdev); 463 unregister_reboot_notifier(&sc1200wdt_notifier); 464 465 #if defined CONFIG_PNP 466 if (isapnp) 467 pnp_unregister_driver(&scl200wdt_pnp_driver); 468 else 469 #endif 470 release_region(io, io_len); 471 } 472 473 module_init(sc1200wdt_init); 474 module_exit(sc1200wdt_exit); 475 476 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>"); 477 MODULE_DESCRIPTION( 478 "Driver for National Semiconductor PC87307/PC97307 watchdog component"); 479 MODULE_LICENSE("GPL"); 480