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#include <linux/uaccess.h> 22#include <linux/io.h> 23 24#define WATCHDOG_NAME "ALi_M1535" 25#define PFX WATCHDOG_NAME ": " 26#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ 27 28/* internal variables */ 29static unsigned long ali_is_open; 30static char ali_expect_release; 31static struct pci_dev *ali_pci; 32static u32 ali_timeout_bits; /* stores the computed timeout */ 33static DEFINE_SPINLOCK(ali_lock); /* Guards the hardware */ 34 35/* module parameters */ 36static int timeout = WATCHDOG_TIMEOUT; 37module_param(timeout, int, 0); 38MODULE_PARM_DESC(timeout, 39 "Watchdog timeout in seconds. (0 < timeout < 18000, default=" 40 __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 41 42static int nowayout = WATCHDOG_NOWAYOUT; 43module_param(nowayout, int, 0); 44MODULE_PARM_DESC(nowayout, 45 "Watchdog cannot be stopped once started (default=" 46 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 47 48/* 49 * ali_start - start watchdog countdown 50 * 51 * Starts the timer running providing the timer has a counter 52 * configuration set. 53 */ 54 55static void ali_start(void) 56{ 57 u32 val; 58 59 spin_lock(&ali_lock); 60 61 pci_read_config_dword(ali_pci, 0xCC, &val); 62 val &= ~0x3F; /* Mask count */ 63 val |= (1 << 25) | ali_timeout_bits; 64 pci_write_config_dword(ali_pci, 0xCC, val); 65 66 spin_unlock(&ali_lock); 67} 68 69/* 70 * ali_stop - stop the timer countdown 71 * 72 * Stop the ALi watchdog countdown 73 */ 74 75static void ali_stop(void) 76{ 77 u32 val; 78 79 spin_lock(&ali_lock); 80 81 pci_read_config_dword(ali_pci, 0xCC, &val); 82 val &= ~0x3F; /* Mask count to zero (disabled) */ 83 val &= ~(1 << 25); /* and for safety mask the reset enable */ 84 pci_write_config_dword(ali_pci, 0xCC, val); 85 86 spin_unlock(&ali_lock); 87} 88 89/* 90 * ali_keepalive - send a keepalive to the watchdog 91 * 92 * Send a keepalive to the timer (actually we restart the timer). 93 */ 94 95static void ali_keepalive(void) 96{ 97 ali_start(); 98} 99 100/* 101 * ali_settimer - compute the timer reload value 102 * @t: time in seconds 103 * 104 * Computes the timeout values needed 105 */ 106 107static int ali_settimer(int t) 108{ 109 if (t < 0) 110 return -EINVAL; 111 else if (t < 60) 112 ali_timeout_bits = t|(1 << 6); 113 else if (t < 3600) 114 ali_timeout_bits = (t / 60)|(1 << 7); 115 else if (t < 18000) 116 ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7); 117 else 118 return -EINVAL; 119 120 timeout = t; 121 return 0; 122} 123 124/* 125 * /dev/watchdog handling 126 */ 127 128/* 129 * ali_write - writes to ALi watchdog 130 * @file: file from VFS 131 * @data: user address of data 132 * @len: length of data 133 * @ppos: pointer to the file offset 134 * 135 * Handle a write to the ALi watchdog. Writing to the file pings 136 * the watchdog and resets it. Writing the magic 'V' sequence allows 137 * the next close to turn off the watchdog. 138 */ 139 140static ssize_t ali_write(struct file *file, const char __user *data, 141 size_t len, loff_t *ppos) 142{ 143 /* See if we got the magic character 'V' and reload the timer */ 144 if (len) { 145 if (!nowayout) { 146 size_t i; 147 148 /* note: just in case someone wrote the 149 magic character five months ago... */ 150 ali_expect_release = 0; 151 152 /* scan to see whether or not we got 153 the magic character */ 154 for (i = 0; i != len; i++) { 155 char c; 156 if (get_user(c, data + i)) 157 return -EFAULT; 158 if (c == 'V') 159 ali_expect_release = 42; 160 } 161 } 162 163 /* someone wrote to us, we should reload the timer */ 164 ali_start(); 165 } 166 return len; 167} 168 169/* 170 * ali_ioctl - handle watchdog ioctls 171 * @file: VFS file pointer 172 * @cmd: ioctl number 173 * @arg: arguments to the ioctl 174 * 175 * Handle the watchdog ioctls supported by the ALi driver. Really 176 * we want an extension to enable irq ack monitoring and the like 177 */ 178 179static long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 180{ 181 void __user *argp = (void __user *)arg; 182 int __user *p = argp; 183 static const struct watchdog_info ident = { 184 .options = WDIOF_KEEPALIVEPING | 185 WDIOF_SETTIMEOUT | 186 WDIOF_MAGICCLOSE, 187 .firmware_version = 0, 188 .identity = "ALi M1535 WatchDog Timer", 189 }; 190 191 switch (cmd) { 192 case WDIOC_GETSUPPORT: 193 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; 194 195 case WDIOC_GETSTATUS: 196 case WDIOC_GETBOOTSTATUS: 197 return put_user(0, p); 198 case WDIOC_SETOPTIONS: 199 { 200 int new_options, retval = -EINVAL; 201 202 if (get_user(new_options, p)) 203 return -EFAULT; 204 if (new_options & WDIOS_DISABLECARD) { 205 ali_stop(); 206 retval = 0; 207 } 208 if (new_options & WDIOS_ENABLECARD) { 209 ali_start(); 210 retval = 0; 211 } 212 return retval; 213 } 214 case WDIOC_KEEPALIVE: 215 ali_keepalive(); 216 return 0; 217 case WDIOC_SETTIMEOUT: 218 { 219 int new_timeout; 220 if (get_user(new_timeout, p)) 221 return -EFAULT; 222 if (ali_settimer(new_timeout)) 223 return -EINVAL; 224 ali_keepalive(); 225 /* Fall */ 226 } 227 case WDIOC_GETTIMEOUT: 228 return put_user(timeout, p); 229 default: 230 return -ENOTTY; 231 } 232} 233 234/* 235 * ali_open - handle open of ali watchdog 236 * @inode: inode from VFS 237 * @file: file from VFS 238 * 239 * Open the ALi watchdog device. Ensure only one person opens it 240 * at a time. Also start the watchdog running. 241 */ 242 243static int ali_open(struct inode *inode, struct file *file) 244{ 245 /* /dev/watchdog can only be opened once */ 246 if (test_and_set_bit(0, &ali_is_open)) 247 return -EBUSY; 248 249 /* Activate */ 250 ali_start(); 251 return nonseekable_open(inode, file); 252} 253 254/* 255 * ali_release - close an ALi watchdog 256 * @inode: inode from VFS 257 * @file: file from VFS 258 * 259 * Close the ALi watchdog device. Actual shutdown of the timer 260 * only occurs if the magic sequence has been set. 261 */ 262 263static int ali_release(struct inode *inode, struct file *file) 264{ 265 /* 266 * Shut off the timer. 267 */ 268 if (ali_expect_release == 42) 269 ali_stop(); 270 else { 271 printk(KERN_CRIT PFX 272 "Unexpected close, not stopping watchdog!\n"); 273 ali_keepalive(); 274 } 275 clear_bit(0, &ali_is_open); 276 ali_expect_release = 0; 277 return 0; 278} 279 280/* 281 * ali_notify_sys - System down notifier 282 * 283 * Notifier for system down 284 */ 285 286 287static int ali_notify_sys(struct notifier_block *this, 288 unsigned long code, void *unused) 289{ 290 if (code == SYS_DOWN || code == SYS_HALT) 291 ali_stop(); /* Turn the WDT off */ 292 return NOTIFY_DONE; 293} 294 295/* 296 * Data for PCI driver interface 297 * 298 * This data only exists for exporting the supported 299 * PCI ids via MODULE_DEVICE_TABLE. We do not actually 300 * register a pci_driver, because someone else might one day 301 * want to register another driver on the same PCI id. 302 */ 303 304static struct pci_device_id ali_pci_tbl[] = { 305 { PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,}, 306 { PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,}, 307 { 0, }, 308}; 309MODULE_DEVICE_TABLE(pci, ali_pci_tbl); 310 311/* 312 * ali_find_watchdog - find a 1535 and 7101 313 * 314 * Scans the PCI hardware for a 1535 series bridge and matching 7101 315 * watchdog device. This may be overtight but it is better to be safe 316 */ 317 318static int __init ali_find_watchdog(void) 319{ 320 struct pci_dev *pdev; 321 u32 wdog; 322 323 /* Check for a 1533/1535 series bridge */ 324 pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL); 325 if (pdev == NULL) 326 pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL); 327 if (pdev == NULL) 328 return -ENODEV; 329 pci_dev_put(pdev); 330 331 /* Check for the a 7101 PMU */ 332 pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL); 333 if (pdev == NULL) 334 return -ENODEV; 335 336 if (pci_enable_device(pdev)) { 337 pci_dev_put(pdev); 338 return -EIO; 339 } 340 341 ali_pci = pdev; 342 343 /* 344 * Initialize the timer bits 345 */ 346 pci_read_config_dword(pdev, 0xCC, &wdog); 347 348 /* Timer bits */ 349 wdog &= ~0x3F; 350 /* Issued events */ 351 wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24)); 352 /* No monitor bits */ 353 wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9)); 354 355 pci_write_config_dword(pdev, 0xCC, wdog); 356 357 return 0; 358} 359 360/* 361 * Kernel Interfaces 362 */ 363 364static const struct file_operations ali_fops = { 365 .owner = THIS_MODULE, 366 .llseek = no_llseek, 367 .write = ali_write, 368 .unlocked_ioctl = ali_ioctl, 369 .open = ali_open, 370 .release = ali_release, 371}; 372 373static struct miscdevice ali_miscdev = { 374 .minor = WATCHDOG_MINOR, 375 .name = "watchdog", 376 .fops = &ali_fops, 377}; 378 379static struct notifier_block ali_notifier = { 380 .notifier_call = ali_notify_sys, 381}; 382 383/* 384 * watchdog_init - module initialiser 385 * 386 * Scan for a suitable watchdog and if so initialize it. Return an error 387 * if we cannot, the error causes the module to unload 388 */ 389 390static int __init watchdog_init(void) 391{ 392 int ret; 393 394 /* Check whether or not the hardware watchdog is there */ 395 if (ali_find_watchdog() != 0) 396 return -ENODEV; 397 398 /* Check that the timeout value is within it's range; 399 if not reset to the default */ 400 if (timeout < 1 || timeout >= 18000) { 401 timeout = WATCHDOG_TIMEOUT; 402 printk(KERN_INFO PFX 403 "timeout value must be 0 < timeout < 18000, using %d\n", 404 timeout); 405 } 406 407 /* Calculate the watchdog's timeout */ 408 ali_settimer(timeout); 409 410 ret = register_reboot_notifier(&ali_notifier); 411 if (ret != 0) { 412 printk(KERN_ERR PFX 413 "cannot register reboot notifier (err=%d)\n", ret); 414 goto out; 415 } 416 417 ret = misc_register(&ali_miscdev); 418 if (ret != 0) { 419 printk(KERN_ERR PFX 420 "cannot register miscdev on minor=%d (err=%d)\n", 421 WATCHDOG_MINOR, ret); 422 goto unreg_reboot; 423 } 424 425 printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n", 426 timeout, nowayout); 427 428out: 429 return ret; 430unreg_reboot: 431 unregister_reboot_notifier(&ali_notifier); 432 goto out; 433} 434 435/* 436 * watchdog_exit - module de-initialiser 437 * 438 * Called while unloading a successfully installed watchdog module. 439 */ 440 441static void __exit watchdog_exit(void) 442{ 443 /* Stop the timer before we leave */ 444 ali_stop(); 445 446 /* Deregister */ 447 misc_deregister(&ali_miscdev); 448 unregister_reboot_notifier(&ali_notifier); 449 pci_dev_put(ali_pci); 450} 451 452module_init(watchdog_init); 453module_exit(watchdog_exit); 454 455MODULE_AUTHOR("Alan Cox"); 456MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver"); 457MODULE_LICENSE("GPL"); 458MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 459