1/* 2 * Watchdog for the 7101 PMU version found in the ALi M1535 chipsets 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 */ 9 10#include <linux/module.h> 11#include <linux/moduleparam.h> 12#include <linux/types.h> 13#include <linux/miscdevice.h> 14#include <linux/watchdog.h> 15#include <linux/ioport.h> 16#include <linux/notifier.h> 17#include <linux/reboot.h> 18#include <linux/init.h> 19#include <linux/fs.h> 20#include <linux/pci.h> 21 22#include <asm/uaccess.h> 23#include <asm/io.h> 24 25#define WATCHDOG_NAME "ALi_M1535" 26#define PFX WATCHDOG_NAME ": " 27#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ 28 29/* internal variables */ 30static unsigned long ali_is_open; 31static char ali_expect_release; 32static struct pci_dev *ali_pci; 33static u32 ali_timeout_bits; /* stores the computed timeout */ 34static spinlock_t ali_lock; /* Guards the hardware */ 35 36/* module parameters */ 37static int timeout = WATCHDOG_TIMEOUT; 38module_param(timeout, int, 0); 39MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (0<timeout<18000, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 40 41static int nowayout = WATCHDOG_NOWAYOUT; 42module_param(nowayout, int, 0); 43MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 44 45/* 46 * ali_start - start watchdog countdown 47 * 48 * Starts the timer running providing the timer has a counter 49 * configuration set. 50 */ 51 52static void ali_start(void) 53{ 54 u32 val; 55 56 spin_lock(&ali_lock); 57 58 pci_read_config_dword(ali_pci, 0xCC, &val); 59 val &= ~0x3F; /* Mask count */ 60 val |= (1<<25) | ali_timeout_bits; 61 pci_write_config_dword(ali_pci, 0xCC, val); 62 63 spin_unlock(&ali_lock); 64} 65 66/* 67 * ali_stop - stop the timer countdown 68 * 69 * Stop the ALi watchdog countdown 70 */ 71 72static void ali_stop(void) 73{ 74 u32 val; 75 76 spin_lock(&ali_lock); 77 78 pci_read_config_dword(ali_pci, 0xCC, &val); 79 val &= ~0x3F; /* Mask count to zero (disabled) */ 80 val &= ~(1<<25);/* and for safety mask the reset enable */ 81 pci_write_config_dword(ali_pci, 0xCC, val); 82 83 spin_unlock(&ali_lock); 84} 85 86/* 87 * ali_keepalive - send a keepalive to the watchdog 88 * 89 * Send a keepalive to the timer (actually we restart the timer). 90 */ 91 92static void ali_keepalive(void) 93{ 94 ali_start(); 95} 96 97/* 98 * ali_settimer - compute the timer reload value 99 * @t: time in seconds 100 * 101 * Computes the timeout values needed 102 */ 103 104static int ali_settimer(int t) 105{ 106 if(t < 0) 107 return -EINVAL; 108 else if(t < 60) 109 ali_timeout_bits = t|(1<<6); 110 else if(t < 3600) 111 ali_timeout_bits = (t/60)|(1<<7); 112 else if(t < 18000) 113 ali_timeout_bits = (t/300)|(1<<6)|(1<<7); 114 else return -EINVAL; 115 116 timeout = t; 117 return 0; 118} 119 120/* 121 * /dev/watchdog handling 122 */ 123 124/* 125 * ali_write - writes to ALi watchdog 126 * @file: file from VFS 127 * @data: user address of data 128 * @len: length of data 129 * @ppos: pointer to the file offset 130 * 131 * Handle a write to the ALi watchdog. Writing to the file pings 132 * the watchdog and resets it. Writing the magic 'V' sequence allows 133 * the next close to turn off the watchdog. 134 */ 135 136static ssize_t ali_write(struct file *file, const char __user *data, 137 size_t len, loff_t * ppos) 138{ 139 /* See if we got the magic character 'V' and reload the timer */ 140 if (len) { 141 if (!nowayout) { 142 size_t i; 143 144 /* note: just in case someone wrote the magic character 145 * five months ago... */ 146 ali_expect_release = 0; 147 148 /* scan to see whether or not we got the magic character */ 149 for (i = 0; i != len; i++) { 150 char c; 151 if(get_user(c, data+i)) 152 return -EFAULT; 153 if (c == 'V') 154 ali_expect_release = 42; 155 } 156 } 157 158 /* someone wrote to us, we should reload the timer */ 159 ali_start(); 160 } 161 return len; 162} 163 164/* 165 * ali_ioctl - handle watchdog ioctls 166 * @inode: VFS inode 167 * @file: VFS file pointer 168 * @cmd: ioctl number 169 * @arg: arguments to the ioctl 170 * 171 * Handle the watchdog ioctls supported by the ALi driver. Really 172 * we want an extension to enable irq ack monitoring and the like 173 */ 174 175static int ali_ioctl(struct inode *inode, struct file *file, 176 unsigned int cmd, unsigned long arg) 177{ 178 void __user *argp = (void __user *)arg; 179 int __user *p = argp; 180 static struct watchdog_info ident = { 181 .options = WDIOF_KEEPALIVEPING | 182 WDIOF_SETTIMEOUT | 183 WDIOF_MAGICCLOSE, 184 .firmware_version = 0, 185 .identity = "ALi M1535 WatchDog Timer", 186 }; 187 188 switch (cmd) { 189 case WDIOC_GETSUPPORT: 190 return copy_to_user(argp, &ident, 191 sizeof (ident)) ? -EFAULT : 0; 192 193 case WDIOC_GETSTATUS: 194 case WDIOC_GETBOOTSTATUS: 195 return put_user(0, p); 196 197 case WDIOC_KEEPALIVE: 198 ali_keepalive(); 199 return 0; 200 201 case WDIOC_SETOPTIONS: 202 { 203 int new_options, retval = -EINVAL; 204 205 if (get_user (new_options, p)) 206 return -EFAULT; 207 208 if (new_options & WDIOS_DISABLECARD) { 209 ali_stop(); 210 retval = 0; 211 } 212 213 if (new_options & WDIOS_ENABLECARD) { 214 ali_start(); 215 retval = 0; 216 } 217 218 return retval; 219 } 220 221 case WDIOC_SETTIMEOUT: 222 { 223 int new_timeout; 224 225 if (get_user(new_timeout, p)) 226 return -EFAULT; 227 228 if (ali_settimer(new_timeout)) 229 return -EINVAL; 230 231 ali_keepalive(); 232 /* Fall */ 233 } 234 235 case WDIOC_GETTIMEOUT: 236 return put_user(timeout, p); 237 238 default: 239 return -ENOTTY; 240 } 241} 242 243/* 244 * ali_open - handle open of ali watchdog 245 * @inode: inode from VFS 246 * @file: file from VFS 247 * 248 * Open the ALi watchdog device. Ensure only one person opens it 249 * at a time. Also start the watchdog running. 250 */ 251 252static int ali_open(struct inode *inode, struct file *file) 253{ 254 /* /dev/watchdog can only be opened once */ 255 if (test_and_set_bit(0, &ali_is_open)) 256 return -EBUSY; 257 258 /* Activate */ 259 ali_start(); 260 return nonseekable_open(inode, file); 261} 262 263/* 264 * ali_release - close an ALi watchdog 265 * @inode: inode from VFS 266 * @file: file from VFS 267 * 268 * Close the ALi watchdog device. Actual shutdown of the timer 269 * only occurs if the magic sequence has been set. 270 */ 271 272static int ali_release(struct inode *inode, struct file *file) 273{ 274 /* 275 * Shut off the timer. 276 */ 277 if (ali_expect_release == 42) { 278 ali_stop(); 279 } else { 280 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); 281 ali_keepalive(); 282 } 283 clear_bit(0, &ali_is_open); 284 ali_expect_release = 0; 285 return 0; 286} 287 288/* 289 * ali_notify_sys - System down notifier 290 * 291 * Notifier for system down 292 */ 293 294 295static int ali_notify_sys(struct notifier_block *this, unsigned long code, void *unused) 296{ 297 if (code==SYS_DOWN || code==SYS_HALT) { 298 /* Turn the WDT off */ 299 ali_stop(); 300 } 301 302 return NOTIFY_DONE; 303} 304 305/* 306 * Data for PCI driver interface 307 * 308 * This data only exists for exporting the supported 309 * PCI ids via MODULE_DEVICE_TABLE. We do not actually 310 * register a pci_driver, because someone else might one day 311 * want to register another driver on the same PCI id. 312 */ 313 314static struct pci_device_id ali_pci_tbl[] = { 315 { PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,}, 316 { 0, }, 317}; 318MODULE_DEVICE_TABLE(pci, ali_pci_tbl); 319 320/* 321 * ali_find_watchdog - find a 1535 and 7101 322 * 323 * Scans the PCI hardware for a 1535 series bridge and matching 7101 324 * watchdog device. This may be overtight but it is better to be safe 325 */ 326 327static int __init ali_find_watchdog(void) 328{ 329 struct pci_dev *pdev; 330 u32 wdog; 331 332 /* Check for a 1535 series bridge */ 333 pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL); 334 if(pdev == NULL) 335 return -ENODEV; 336 pci_dev_put(pdev); 337 338 /* Check for the a 7101 PMU */ 339 pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL); 340 if(pdev == NULL) 341 return -ENODEV; 342 343 if(pci_enable_device(pdev)) { 344 pci_dev_put(pdev); 345 return -EIO; 346 } 347 348 ali_pci = pdev; 349 350 /* 351 * Initialize the timer bits 352 */ 353 pci_read_config_dword(pdev, 0xCC, &wdog); 354 355 wdog &= ~0x3F; /* Timer bits */ 356 wdog &= ~((1<<27)|(1<<26)|(1<<25)|(1<<24)); /* Issued events */ 357 wdog &= ~((1<<16)|(1<<13)|(1<<12)|(1<<11)|(1<<10)|(1<<9)); /* No monitor bits */ 358 359 pci_write_config_dword(pdev, 0xCC, wdog); 360 361 return 0; 362} 363 364/* 365 * Kernel Interfaces 366 */ 367 368static const struct file_operations ali_fops = { 369 .owner = THIS_MODULE, 370 .llseek = no_llseek, 371 .write = ali_write, 372 .ioctl = ali_ioctl, 373 .open = ali_open, 374 .release = ali_release, 375}; 376 377static struct miscdevice ali_miscdev = { 378 .minor = WATCHDOG_MINOR, 379 .name = "watchdog", 380 .fops = &ali_fops, 381}; 382 383static struct notifier_block ali_notifier = { 384 .notifier_call = ali_notify_sys, 385}; 386 387/* 388 * watchdog_init - module initialiser 389 * 390 * Scan for a suitable watchdog and if so initialize it. Return an error 391 * if we cannot, the error causes the module to unload 392 */ 393 394static int __init watchdog_init(void) 395{ 396 int ret; 397 398 spin_lock_init(&ali_lock); 399 400 /* Check whether or not the hardware watchdog is there */ 401 if (ali_find_watchdog() != 0) { 402 return -ENODEV; 403 } 404 405 /* Check that the timeout value is within it's range ; if not reset to the default */ 406 if (timeout < 1 || timeout >= 18000) { 407 timeout = WATCHDOG_TIMEOUT; 408 printk(KERN_INFO PFX "timeout value must be 0<timeout<18000, using %d\n", 409 timeout); 410 } 411 412 /* Calculate the watchdog's timeout */ 413 ali_settimer(timeout); 414 415 ret = misc_register(&ali_miscdev); 416 if (ret != 0) { 417 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", 418 WATCHDOG_MINOR, ret); 419 goto out; 420 } 421 422 ret = register_reboot_notifier(&ali_notifier); 423 if (ret != 0) { 424 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", 425 ret); 426 goto unreg_miscdev; 427 } 428 429 printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n", 430 timeout, nowayout); 431 432out: 433 return ret; 434unreg_miscdev: 435 misc_deregister(&ali_miscdev); 436 goto out; 437} 438 439/* 440 * watchdog_exit - module de-initialiser 441 * 442 * Called while unloading a successfully installed watchdog module. 443 */ 444 445static void __exit watchdog_exit(void) 446{ 447 /* Stop the timer before we leave */ 448 ali_stop(); 449 450 /* Deregister */ 451 unregister_reboot_notifier(&ali_notifier); 452 misc_deregister(&ali_miscdev); 453 pci_dev_put(ali_pci); 454} 455 456module_init(watchdog_init); 457module_exit(watchdog_exit); 458 459MODULE_AUTHOR("Alan Cox"); 460MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver"); 461MODULE_LICENSE("GPL"); 462MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 463