1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver 4 * (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>, 5 * All Rights Reserved. 6 * Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively. 7 * 8 * The author(s) of this software shall not be held liable for damages 9 * of any nature resulting due to the use of this software. This 10 * software is provided AS-IS with no warranties. 11 * 12 * Changelog: 13 * 20020220 Zwane Mwaikambo Code based on datasheet, no hardware. 14 * 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik 15 * and Alan Cox. 16 * 20020222 Zwane Mwaikambo Added probing. 17 * 20020225 Zwane Mwaikambo Added ISAPNP support. 18 * 20020412 Rob Radez Broke out start/stop functions 19 * <rob@osinvestor.com> Return proper status instead of 20 * temperature warning 21 * Add WDIOC_GETBOOTSTATUS and 22 * WDIOC_SETOPTIONS ioctls 23 * Fix CONFIG_WATCHDOG_NOWAYOUT 24 * 20020530 Joel Becker Add Matt Domsch's nowayout module 25 * option 26 * 20030116 Adam Belay Updated to the latest pnp code 27 */ 28 29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 30 31 #include <linux/module.h> 32 #include <linux/moduleparam.h> 33 #include <linux/miscdevice.h> 34 #include <linux/watchdog.h> 35 #include <linux/ioport.h> 36 #include <linux/spinlock.h> 37 #include <linux/notifier.h> 38 #include <linux/reboot.h> 39 #include <linux/init.h> 40 #include <linux/pnp.h> 41 #include <linux/fs.h> 42 #include <linux/semaphore.h> 43 #include <linux/io.h> 44 #include <linux/uaccess.h> 45 46 #define SC1200_MODULE_VER "build 20020303" 47 #define SC1200_MODULE_NAME "sc1200wdt" 48 49 #define MAX_TIMEOUT 255 /* 255 minutes */ 50 #define PMIR (io) /* Power Management Index Register */ 51 #define PMDR (io+1) /* Power Management Data Register */ 52 53 /* Data Register indexes */ 54 #define FER1 0x00 /* Function enable register 1 */ 55 #define FER2 0x01 /* Function enable register 2 */ 56 #define PMC1 0x02 /* Power Management Ctrl 1 */ 57 #define PMC2 0x03 /* Power Management Ctrl 2 */ 58 #define PMC3 0x04 /* Power Management Ctrl 3 */ 59 #define WDTO 0x05 /* Watchdog timeout register */ 60 #define WDCF 0x06 /* Watchdog config register */ 61 #define WDST 0x07 /* Watchdog status register */ 62 63 /* WDCF bitfields - which devices assert WDO */ 64 #define KBC_IRQ 0x01 /* Keyboard Controller */ 65 #define MSE_IRQ 0x02 /* Mouse */ 66 #define UART1_IRQ 0x03 /* Serial0 */ 67 #define UART2_IRQ 0x04 /* Serial1 */ 68 /* 5 -7 are reserved */ 69 70 static int timeout = 1; 71 static int io = -1; 72 static int io_len = 2; /* for non plug and play */ 73 static unsigned long open_flag; 74 static char expect_close; 75 static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */ 76 77 #if defined CONFIG_PNP 78 static int isapnp = 1; 79 static struct pnp_dev *wdt_dev; 80 81 module_param(isapnp, int, 0); 82 MODULE_PARM_DESC(isapnp, 83 "When set to 0 driver ISA PnP support will be disabled"); 84 #endif 85 86 module_param_hw(io, int, ioport, 0); 87 MODULE_PARM_DESC(io, "io port"); 88 module_param(timeout, int, 0); 89 MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1"); 90 91 static bool nowayout = WATCHDOG_NOWAYOUT; 92 module_param(nowayout, bool, 0); 93 MODULE_PARM_DESC(nowayout, 94 "Watchdog cannot be stopped once started (default=" 95 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 96 97 98 99 /* Read from Data Register */ 100 static inline void __sc1200wdt_read_data(unsigned char index, 101 unsigned char *data) 102 { 103 outb_p(index, PMIR); 104 *data = inb(PMDR); 105 } 106 107 static void sc1200wdt_read_data(unsigned char index, unsigned char *data) 108 { 109 spin_lock(&sc1200wdt_lock); 110 __sc1200wdt_read_data(index, data); 111 spin_unlock(&sc1200wdt_lock); 112 } 113 114 /* Write to Data Register */ 115 static inline void __sc1200wdt_write_data(unsigned char index, 116 unsigned char data) 117 { 118 outb_p(index, PMIR); 119 outb(data, PMDR); 120 } 121 122 static inline void sc1200wdt_write_data(unsigned char index, 123 unsigned char data) 124 { 125 spin_lock(&sc1200wdt_lock); 126 __sc1200wdt_write_data(index, data); 127 spin_unlock(&sc1200wdt_lock); 128 } 129 130 131 static void sc1200wdt_start(void) 132 { 133 unsigned char reg; 134 spin_lock(&sc1200wdt_lock); 135 136 __sc1200wdt_read_data(WDCF, ®); 137 /* assert WDO when any of the following interrupts are triggered too */ 138 reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ); 139 __sc1200wdt_write_data(WDCF, reg); 140 /* set the timeout and get the ball rolling */ 141 __sc1200wdt_write_data(WDTO, timeout); 142 143 spin_unlock(&sc1200wdt_lock); 144 } 145 146 static void sc1200wdt_stop(void) 147 { 148 sc1200wdt_write_data(WDTO, 0); 149 } 150 151 /* This returns the status of the WDO signal, inactive high. */ 152 static inline int sc1200wdt_status(void) 153 { 154 unsigned char ret; 155 156 sc1200wdt_read_data(WDST, &ret); 157 /* If the bit is inactive, the watchdog is enabled, so return 158 * KEEPALIVEPING which is a bit of a kludge because there's nothing 159 * else for enabled/disabled status 160 */ 161 return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING; 162 } 163 164 static int sc1200wdt_open(struct inode *inode, struct file *file) 165 { 166 /* allow one at a time */ 167 if (test_and_set_bit(0, &open_flag)) 168 return -EBUSY; 169 170 if (timeout > MAX_TIMEOUT) 171 timeout = MAX_TIMEOUT; 172 173 sc1200wdt_start(); 174 pr_info("Watchdog enabled, timeout = %d min(s)", timeout); 175 176 return stream_open(inode, file); 177 } 178 179 180 static long sc1200wdt_ioctl(struct file *file, unsigned int cmd, 181 unsigned long arg) 182 { 183 int new_timeout; 184 void __user *argp = (void __user *)arg; 185 int __user *p = argp; 186 static const struct watchdog_info ident = { 187 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | 188 WDIOF_MAGICCLOSE, 189 .firmware_version = 0, 190 .identity = "PC87307/PC97307", 191 }; 192 193 switch (cmd) { 194 case WDIOC_GETSUPPORT: 195 if (copy_to_user(argp, &ident, sizeof(ident))) 196 return -EFAULT; 197 return 0; 198 199 case WDIOC_GETSTATUS: 200 return put_user(sc1200wdt_status(), p); 201 202 case WDIOC_GETBOOTSTATUS: 203 return put_user(0, p); 204 205 case WDIOC_SETOPTIONS: 206 { 207 int options, retval = -EINVAL; 208 209 if (get_user(options, p)) 210 return -EFAULT; 211 212 if (options & WDIOS_DISABLECARD) { 213 sc1200wdt_stop(); 214 retval = 0; 215 } 216 217 if (options & WDIOS_ENABLECARD) { 218 sc1200wdt_start(); 219 retval = 0; 220 } 221 222 return retval; 223 } 224 case WDIOC_KEEPALIVE: 225 sc1200wdt_write_data(WDTO, timeout); 226 return 0; 227 228 case WDIOC_SETTIMEOUT: 229 if (get_user(new_timeout, p)) 230 return -EFAULT; 231 /* the API states this is given in secs */ 232 new_timeout /= 60; 233 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) 234 return -EINVAL; 235 timeout = new_timeout; 236 sc1200wdt_write_data(WDTO, timeout); 237 fallthrough; /* and return the new timeout */ 238 239 case WDIOC_GETTIMEOUT: 240 return put_user(timeout * 60, p); 241 242 default: 243 return -ENOTTY; 244 } 245 } 246 247 248 static int sc1200wdt_release(struct inode *inode, struct file *file) 249 { 250 if (expect_close == 42) { 251 sc1200wdt_stop(); 252 pr_info("Watchdog disabled\n"); 253 } else { 254 sc1200wdt_write_data(WDTO, timeout); 255 pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout); 256 } 257 clear_bit(0, &open_flag); 258 expect_close = 0; 259 260 return 0; 261 } 262 263 264 static ssize_t sc1200wdt_write(struct file *file, const char __user *data, 265 size_t len, loff_t *ppos) 266 { 267 if (len) { 268 if (!nowayout) { 269 size_t i; 270 271 expect_close = 0; 272 273 for (i = 0; i != len; i++) { 274 char c; 275 276 if (get_user(c, data + i)) 277 return -EFAULT; 278 if (c == 'V') 279 expect_close = 42; 280 } 281 } 282 283 sc1200wdt_write_data(WDTO, timeout); 284 return len; 285 } 286 287 return 0; 288 } 289 290 291 static int sc1200wdt_notify_sys(struct notifier_block *this, 292 unsigned long code, void *unused) 293 { 294 if (code == SYS_DOWN || code == SYS_HALT) 295 sc1200wdt_stop(); 296 297 return NOTIFY_DONE; 298 } 299 300 301 static struct notifier_block sc1200wdt_notifier = { 302 .notifier_call = sc1200wdt_notify_sys, 303 }; 304 305 static const struct file_operations sc1200wdt_fops = { 306 .owner = THIS_MODULE, 307 .llseek = no_llseek, 308 .write = sc1200wdt_write, 309 .unlocked_ioctl = sc1200wdt_ioctl, 310 .compat_ioctl = compat_ptr_ioctl, 311 .open = sc1200wdt_open, 312 .release = sc1200wdt_release, 313 }; 314 315 static struct miscdevice sc1200wdt_miscdev = { 316 .minor = WATCHDOG_MINOR, 317 .name = "watchdog", 318 .fops = &sc1200wdt_fops, 319 }; 320 321 322 static int __init sc1200wdt_probe(void) 323 { 324 /* The probe works by reading the PMC3 register's default value of 0x0e 325 * there is one caveat, if the device disables the parallel port or any 326 * of the UARTs we won't be able to detect it. 327 * NB. This could be done with accuracy by reading the SID registers, 328 * but we don't have access to those io regions. 329 */ 330 331 unsigned char reg; 332 333 sc1200wdt_read_data(PMC3, ®); 334 reg &= 0x0f; /* we don't want the UART busy bits */ 335 return (reg == 0x0e) ? 0 : -ENODEV; 336 } 337 338 339 #if defined CONFIG_PNP 340 341 static const struct pnp_device_id scl200wdt_pnp_devices[] = { 342 /* National Semiconductor PC87307/PC97307 watchdog component */ 343 {.id = "NSC0800", .driver_data = 0}, 344 {.id = ""}, 345 }; 346 347 static int scl200wdt_pnp_probe(struct pnp_dev *dev, 348 const struct pnp_device_id *dev_id) 349 { 350 /* this driver only supports one card at a time */ 351 if (wdt_dev || !isapnp) 352 return -EBUSY; 353 354 wdt_dev = dev; 355 io = pnp_port_start(wdt_dev, 0); 356 io_len = pnp_port_len(wdt_dev, 0); 357 358 if (!request_region(io, io_len, SC1200_MODULE_NAME)) { 359 pr_err("Unable to register IO port %#x\n", io); 360 return -EBUSY; 361 } 362 363 pr_info("PnP device found at io port %#x/%d\n", io, io_len); 364 return 0; 365 } 366 367 static void scl200wdt_pnp_remove(struct pnp_dev *dev) 368 { 369 if (wdt_dev) { 370 release_region(io, io_len); 371 wdt_dev = NULL; 372 } 373 } 374 375 static struct pnp_driver scl200wdt_pnp_driver = { 376 .name = "scl200wdt", 377 .id_table = scl200wdt_pnp_devices, 378 .probe = scl200wdt_pnp_probe, 379 .remove = scl200wdt_pnp_remove, 380 }; 381 382 #endif /* CONFIG_PNP */ 383 384 385 static int __init sc1200wdt_init(void) 386 { 387 int ret; 388 389 pr_info("%s\n", SC1200_MODULE_VER); 390 391 #if defined CONFIG_PNP 392 if (isapnp) { 393 ret = pnp_register_driver(&scl200wdt_pnp_driver); 394 if (ret) 395 goto out_clean; 396 } 397 #endif 398 399 if (io == -1) { 400 pr_err("io parameter must be specified\n"); 401 ret = -EINVAL; 402 goto out_pnp; 403 } 404 405 #if defined CONFIG_PNP 406 /* now that the user has specified an IO port and we haven't detected 407 * any devices, disable pnp support */ 408 if (isapnp) 409 pnp_unregister_driver(&scl200wdt_pnp_driver); 410 isapnp = 0; 411 #endif 412 413 if (!request_region(io, io_len, SC1200_MODULE_NAME)) { 414 pr_err("Unable to register IO port %#x\n", io); 415 ret = -EBUSY; 416 goto out_pnp; 417 } 418 419 ret = sc1200wdt_probe(); 420 if (ret) 421 goto out_io; 422 423 ret = register_reboot_notifier(&sc1200wdt_notifier); 424 if (ret) { 425 pr_err("Unable to register reboot notifier err = %d\n", ret); 426 goto out_io; 427 } 428 429 ret = misc_register(&sc1200wdt_miscdev); 430 if (ret) { 431 pr_err("Unable to register miscdev on minor %d\n", 432 WATCHDOG_MINOR); 433 goto out_rbt; 434 } 435 436 /* ret = 0 */ 437 438 out_clean: 439 return ret; 440 441 out_rbt: 442 unregister_reboot_notifier(&sc1200wdt_notifier); 443 444 out_io: 445 release_region(io, io_len); 446 447 out_pnp: 448 #if defined CONFIG_PNP 449 if (isapnp) 450 pnp_unregister_driver(&scl200wdt_pnp_driver); 451 #endif 452 goto out_clean; 453 } 454 455 456 static void __exit sc1200wdt_exit(void) 457 { 458 misc_deregister(&sc1200wdt_miscdev); 459 unregister_reboot_notifier(&sc1200wdt_notifier); 460 461 #if defined CONFIG_PNP 462 if (isapnp) 463 pnp_unregister_driver(&scl200wdt_pnp_driver); 464 else 465 #endif 466 release_region(io, io_len); 467 } 468 469 module_init(sc1200wdt_init); 470 module_exit(sc1200wdt_exit); 471 472 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>"); 473 MODULE_DESCRIPTION( 474 "Driver for National Semiconductor PC87307/PC97307 watchdog component"); 475 MODULE_LICENSE("GPL"); 476