Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * ALi M7101 PMU Computer Watchdog Timer driver |
| 3 | * |
| 4 | * Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net> |
| 5 | * and the Cobalt kernel WDT timer driver by Tim Hockin |
| 6 | * <thockin@cobaltnet.com> |
| 7 | * |
| 8 | * (c)2002 Steve Hill <steve@navaho.co.uk> |
| 9 | * |
| 10 | * This WDT driver is different from most other Linux WDT |
| 11 | * drivers in that the driver will ping the watchdog by itself, |
| 12 | * because this particular WDT has a very short timeout (1.6 |
| 13 | * seconds) and it would be insane to count on any userspace |
| 14 | * daemon always getting scheduled within that time frame. |
| 15 | * |
| 16 | * Additions: |
| 17 | * Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs |
| 18 | * found on very old cobalt hardware. |
| 19 | * -- Mike Waychison <michael.waychison@sun.com> |
| 20 | */ |
| 21 | |
| 22 | #include <linux/module.h> |
| 23 | #include <linux/moduleparam.h> |
| 24 | #include <linux/types.h> |
| 25 | #include <linux/timer.h> |
| 26 | #include <linux/miscdevice.h> |
| 27 | #include <linux/watchdog.h> |
| 28 | #include <linux/ioport.h> |
| 29 | #include <linux/notifier.h> |
| 30 | #include <linux/reboot.h> |
| 31 | #include <linux/init.h> |
| 32 | #include <linux/fs.h> |
| 33 | #include <linux/pci.h> |
| 34 | |
| 35 | #include <asm/io.h> |
| 36 | #include <asm/uaccess.h> |
| 37 | #include <asm/system.h> |
| 38 | |
| 39 | #define OUR_NAME "alim7101_wdt" |
| 40 | #define PFX OUR_NAME ": " |
| 41 | |
| 42 | #define WDT_ENABLE 0x9C |
| 43 | #define WDT_DISABLE 0x8C |
| 44 | |
| 45 | #define ALI_7101_WDT 0x92 |
| 46 | #define ALI_7101_GPIO 0x7D |
| 47 | #define ALI_7101_GPIO_O 0x7E |
| 48 | #define ALI_WDT_ARM 0x01 |
| 49 | |
| 50 | /* |
| 51 | * We're going to use a 1 second timeout. |
| 52 | * If we reset the watchdog every ~250ms we should be safe. */ |
| 53 | |
| 54 | #define WDT_INTERVAL (HZ/4+1) |
| 55 | |
| 56 | /* |
| 57 | * We must not require too good response from the userspace daemon. |
| 58 | * Here we require the userspace daemon to send us a heartbeat |
| 59 | * char to /dev/watchdog every 30 seconds. |
| 60 | */ |
| 61 | |
| 62 | #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ |
| 63 | static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ |
| 64 | module_param(timeout, int, 0); |
| 65 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
| 66 | |
| 67 | static int use_gpio = 0; /* Use the pic (for a1d revision alim7101) */ |
| 68 | module_param(use_gpio, int, 0); |
| 69 | MODULE_PARM_DESC(use_gpio, "Use the gpio watchdog. (required by old cobalt boards)"); |
| 70 | |
| 71 | static void wdt_timer_ping(unsigned long); |
| 72 | static struct timer_list timer; |
| 73 | static unsigned long next_heartbeat; |
| 74 | static unsigned long wdt_is_open; |
| 75 | static char wdt_expect_close; |
| 76 | static struct pci_dev *alim7101_pmu; |
| 77 | |
Andrey Panin | 4bfdf37 | 2005-07-27 11:43:58 -0700 | [diff] [blame] | 78 | static int nowayout = WATCHDOG_NOWAYOUT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | module_param(nowayout, int, 0); |
| 80 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); |
| 81 | |
| 82 | /* |
| 83 | * Whack the dog |
| 84 | */ |
| 85 | |
| 86 | static void wdt_timer_ping(unsigned long data) |
| 87 | { |
| 88 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL |
| 89 | * we agree to ping the WDT |
| 90 | */ |
| 91 | char tmp; |
| 92 | |
| 93 | if(time_before(jiffies, next_heartbeat)) |
| 94 | { |
| 95 | /* Ping the WDT (this is actually a disarm/arm sequence) */ |
| 96 | pci_read_config_byte(alim7101_pmu, 0x92, &tmp); |
| 97 | pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); |
| 98 | pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM)); |
| 99 | if (use_gpio) { |
| 100 | pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp); |
| 101 | pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp |
| 102 | | 0x20); |
| 103 | pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp |
| 104 | & ~0x20); |
| 105 | } |
| 106 | } else { |
| 107 | printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n"); |
| 108 | } |
| 109 | /* Re-set the timer interval */ |
| 110 | timer.expires = jiffies + WDT_INTERVAL; |
| 111 | add_timer(&timer); |
| 112 | } |
| 113 | |
| 114 | /* |
| 115 | * Utility routines |
| 116 | */ |
| 117 | |
| 118 | static void wdt_change(int writeval) |
| 119 | { |
| 120 | char tmp; |
| 121 | |
| 122 | pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp); |
| 123 | if (writeval == WDT_ENABLE) { |
| 124 | pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM)); |
| 125 | if (use_gpio) { |
| 126 | pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp); |
| 127 | pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp & ~0x20); |
| 128 | } |
| 129 | |
| 130 | } else { |
| 131 | pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); |
| 132 | if (use_gpio) { |
| 133 | pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp); |
| 134 | pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp | 0x20); |
| 135 | } |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | static void wdt_startup(void) |
| 140 | { |
| 141 | next_heartbeat = jiffies + (timeout * HZ); |
| 142 | |
| 143 | /* We must enable before we kick off the timer in case the timer |
| 144 | occurs as we ping it */ |
| 145 | |
| 146 | wdt_change(WDT_ENABLE); |
| 147 | |
| 148 | /* Start the timer */ |
| 149 | timer.expires = jiffies + WDT_INTERVAL; |
| 150 | add_timer(&timer); |
| 151 | |
| 152 | |
| 153 | printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); |
| 154 | } |
| 155 | |
| 156 | static void wdt_turnoff(void) |
| 157 | { |
| 158 | /* Stop the timer */ |
| 159 | del_timer_sync(&timer); |
| 160 | wdt_change(WDT_DISABLE); |
| 161 | printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); |
| 162 | } |
| 163 | |
| 164 | static void wdt_keepalive(void) |
| 165 | { |
| 166 | /* user land ping */ |
| 167 | next_heartbeat = jiffies + (timeout * HZ); |
| 168 | } |
| 169 | |
| 170 | /* |
| 171 | * /dev/watchdog handling |
| 172 | */ |
| 173 | |
| 174 | static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos) |
| 175 | { |
| 176 | /* See if we got the magic character 'V' and reload the timer */ |
| 177 | if(count) { |
| 178 | if (!nowayout) { |
| 179 | size_t ofs; |
| 180 | |
| 181 | /* note: just in case someone wrote the magic character |
| 182 | * five months ago... */ |
| 183 | wdt_expect_close = 0; |
| 184 | |
| 185 | /* now scan */ |
| 186 | for (ofs = 0; ofs != count; ofs++) { |
| 187 | char c; |
| 188 | if (get_user(c, buf+ofs)) |
| 189 | return -EFAULT; |
| 190 | if (c == 'V') |
| 191 | wdt_expect_close = 42; |
| 192 | } |
| 193 | } |
| 194 | /* someone wrote to us, we should restart timer */ |
| 195 | wdt_keepalive(); |
| 196 | } |
| 197 | return count; |
| 198 | } |
| 199 | |
| 200 | static int fop_open(struct inode * inode, struct file * file) |
| 201 | { |
| 202 | /* Just in case we're already talking to someone... */ |
| 203 | if(test_and_set_bit(0, &wdt_is_open)) |
| 204 | return -EBUSY; |
| 205 | /* Good, fire up the show */ |
| 206 | wdt_startup(); |
| 207 | return nonseekable_open(inode, file); |
| 208 | } |
| 209 | |
| 210 | static int fop_close(struct inode * inode, struct file * file) |
| 211 | { |
| 212 | if(wdt_expect_close == 42) |
| 213 | wdt_turnoff(); |
| 214 | else { |
| 215 | /* wim: shouldn't there be a: del_timer(&timer); */ |
| 216 | printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n"); |
| 217 | } |
| 218 | clear_bit(0, &wdt_is_open); |
| 219 | wdt_expect_close = 0; |
| 220 | return 0; |
| 221 | } |
| 222 | |
| 223 | static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) |
| 224 | { |
| 225 | void __user *argp = (void __user *)arg; |
| 226 | int __user *p = argp; |
| 227 | static struct watchdog_info ident = |
| 228 | { |
| 229 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, |
| 230 | .firmware_version = 1, |
| 231 | .identity = "ALiM7101", |
| 232 | }; |
| 233 | |
| 234 | switch(cmd) |
| 235 | { |
| 236 | case WDIOC_GETSUPPORT: |
| 237 | return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0; |
| 238 | case WDIOC_GETSTATUS: |
| 239 | case WDIOC_GETBOOTSTATUS: |
| 240 | return put_user(0, p); |
| 241 | case WDIOC_KEEPALIVE: |
| 242 | wdt_keepalive(); |
| 243 | return 0; |
| 244 | case WDIOC_SETOPTIONS: |
| 245 | { |
| 246 | int new_options, retval = -EINVAL; |
| 247 | |
| 248 | if(get_user(new_options, p)) |
| 249 | return -EFAULT; |
| 250 | |
| 251 | if(new_options & WDIOS_DISABLECARD) { |
| 252 | wdt_turnoff(); |
| 253 | retval = 0; |
| 254 | } |
| 255 | |
| 256 | if(new_options & WDIOS_ENABLECARD) { |
| 257 | wdt_startup(); |
| 258 | retval = 0; |
| 259 | } |
| 260 | |
| 261 | return retval; |
| 262 | } |
| 263 | case WDIOC_SETTIMEOUT: |
| 264 | { |
| 265 | int new_timeout; |
| 266 | |
| 267 | if(get_user(new_timeout, p)) |
| 268 | return -EFAULT; |
| 269 | |
| 270 | if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */ |
| 271 | return -EINVAL; |
| 272 | |
| 273 | timeout = new_timeout; |
| 274 | wdt_keepalive(); |
| 275 | /* Fall through */ |
| 276 | } |
| 277 | case WDIOC_GETTIMEOUT: |
| 278 | return put_user(timeout, p); |
| 279 | default: |
| 280 | return -ENOIOCTLCMD; |
| 281 | } |
| 282 | } |
| 283 | |
| 284 | static struct file_operations wdt_fops = { |
| 285 | .owner= THIS_MODULE, |
| 286 | .llseek= no_llseek, |
| 287 | .write= fop_write, |
| 288 | .open= fop_open, |
| 289 | .release= fop_close, |
| 290 | .ioctl= fop_ioctl, |
| 291 | }; |
| 292 | |
| 293 | static struct miscdevice wdt_miscdev = { |
| 294 | .minor=WATCHDOG_MINOR, |
| 295 | .name="watchdog", |
| 296 | .fops=&wdt_fops, |
| 297 | }; |
| 298 | |
| 299 | /* |
| 300 | * Notifier for system down |
| 301 | */ |
| 302 | |
| 303 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) |
| 304 | { |
| 305 | if (code==SYS_DOWN || code==SYS_HALT) |
| 306 | wdt_turnoff(); |
| 307 | |
| 308 | if (code==SYS_RESTART) { |
| 309 | /* |
| 310 | * Cobalt devices have no way of rebooting themselves other than |
| 311 | * getting the watchdog to pull reset, so we restart the watchdog on |
| 312 | * reboot with no heartbeat |
| 313 | */ |
| 314 | wdt_change(WDT_ENABLE); |
| 315 | printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n"); |
| 316 | } |
| 317 | return NOTIFY_DONE; |
| 318 | } |
| 319 | |
| 320 | /* |
| 321 | * The WDT needs to learn about soft shutdowns in order to |
| 322 | * turn the timebomb registers off. |
| 323 | */ |
| 324 | |
| 325 | static struct notifier_block wdt_notifier= |
| 326 | { |
| 327 | .notifier_call = wdt_notify_sys, |
| 328 | }; |
| 329 | |
| 330 | static void __exit alim7101_wdt_unload(void) |
| 331 | { |
| 332 | wdt_turnoff(); |
| 333 | /* Deregister */ |
| 334 | misc_deregister(&wdt_miscdev); |
| 335 | unregister_reboot_notifier(&wdt_notifier); |
| 336 | } |
| 337 | |
| 338 | static int __init alim7101_wdt_init(void) |
| 339 | { |
| 340 | int rc = -EBUSY; |
| 341 | struct pci_dev *ali1543_south; |
| 342 | char tmp; |
| 343 | |
| 344 | printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n"); |
| 345 | alim7101_pmu = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,NULL); |
| 346 | if (!alim7101_pmu) { |
| 347 | printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n"); |
| 348 | return -EBUSY; |
| 349 | } |
| 350 | |
| 351 | /* Set the WDT in the PMU to 1 second */ |
| 352 | pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02); |
| 353 | |
| 354 | ali1543_south = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, NULL); |
| 355 | if (!ali1543_south) { |
| 356 | printk(KERN_INFO PFX "ALi 1543 South-Bridge not present - WDT not set\n"); |
| 357 | return -EBUSY; |
| 358 | } |
| 359 | pci_read_config_byte(ali1543_south, 0x5e, &tmp); |
| 360 | if ((tmp & 0x1e) == 0x00) { |
| 361 | if (!use_gpio) { |
| 362 | printk(KERN_INFO PFX "Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n"); |
| 363 | return -EBUSY; |
| 364 | } |
| 365 | nowayout = 1; |
| 366 | } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) { |
| 367 | printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n"); |
| 368 | return -EBUSY; |
| 369 | } |
| 370 | |
| 371 | if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */ |
| 372 | { |
| 373 | timeout = WATCHDOG_TIMEOUT; |
| 374 | printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n", |
| 375 | timeout); |
| 376 | } |
| 377 | |
| 378 | init_timer(&timer); |
| 379 | timer.function = wdt_timer_ping; |
| 380 | timer.data = 1; |
| 381 | |
| 382 | rc = misc_register(&wdt_miscdev); |
| 383 | if (rc) { |
| 384 | printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", |
| 385 | wdt_miscdev.minor, rc); |
| 386 | goto err_out; |
| 387 | } |
| 388 | |
| 389 | rc = register_reboot_notifier(&wdt_notifier); |
| 390 | if (rc) { |
| 391 | printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", |
| 392 | rc); |
| 393 | goto err_out_miscdev; |
| 394 | } |
| 395 | |
| 396 | if (nowayout) { |
| 397 | __module_get(THIS_MODULE); |
| 398 | } |
| 399 | |
| 400 | printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n", |
| 401 | timeout, nowayout); |
| 402 | return 0; |
| 403 | |
| 404 | err_out_miscdev: |
| 405 | misc_deregister(&wdt_miscdev); |
| 406 | err_out: |
| 407 | return rc; |
| 408 | } |
| 409 | |
| 410 | module_init(alim7101_wdt_init); |
| 411 | module_exit(alim7101_wdt_unload); |
| 412 | |
| 413 | MODULE_AUTHOR("Steve Hill"); |
| 414 | MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver"); |
| 415 | MODULE_LICENSE("GPL"); |
| 416 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |