| 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 */ |
| 29 | static unsigned long ali_is_open; |
| 30 | static char ali_expect_release; |
| 31 | static struct pci_dev *ali_pci; |
| 32 | static u32 ali_timeout_bits; /* stores the computed timeout */ |
| 33 | static DEFINE_SPINLOCK(ali_lock); /* Guards the hardware */ |
| 34 | |
| 35 | /* module parameters */ |
| 36 | static int timeout = WATCHDOG_TIMEOUT; |
| 37 | module_param(timeout, int, 0); |
| 38 | MODULE_PARM_DESC(timeout, |
| 39 | "Watchdog timeout in seconds. (0 < timeout < 18000, default=" |
| 40 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
| 41 | |
| 42 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 43 | module_param(nowayout, int, 0); |
| 44 | MODULE_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 | |
| 55 | static 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 | |
| 75 | static 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 | |
| 95 | static 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 | |
| 107 | static 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 | |
| 140 | static 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 | |
| 179 | static 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 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 | |
| 243 | static 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 | |
| 263 | static 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 | |
| 287 | static 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 | |
| 304 | static 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 | }; |
| 309 | MODULE_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 | |
| 318 | static 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 | |
| 364 | static 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 | |
| 373 | static struct miscdevice ali_miscdev = { |
| 374 | .minor = WATCHDOG_MINOR, |
| 375 | .name = "watchdog", |
| 376 | .fops = &ali_fops, |
| 377 | }; |
| 378 | |
| 379 | static 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 | |
| 390 | static 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 | |
| 428 | out: |
| 429 | return ret; |
| 430 | unreg_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 | |
| 441 | static 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 | |
| 452 | module_init(watchdog_init); |
| 453 | module_exit(watchdog_exit); |
| 454 | |
| 455 | MODULE_AUTHOR("Alan Cox"); |
| 456 | MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver"); |
| 457 | MODULE_LICENSE("GPL"); |
| 458 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |