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