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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 <linux/io.h> | |
36 | #include <linux/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 | /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ | |
64 | static int timeout = WATCHDOG_TIMEOUT; | |
65 | module_param(timeout, int, 0); | |
66 | MODULE_PARM_DESC(timeout, | |
67 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" | |
68 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
69 | ||
70 | static int use_gpio; /* Use the pic (for a1d revision alim7101) */ | |
71 | module_param(use_gpio, int, 0); | |
72 | MODULE_PARM_DESC(use_gpio, | |
73 | "Use the gpio watchdog (required by old cobalt boards)."); | |
74 | ||
75 | static void wdt_timer_ping(unsigned long); | |
76 | static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1); | |
77 | static unsigned long next_heartbeat; | |
78 | static unsigned long wdt_is_open; | |
79 | static char wdt_expect_close; | |
80 | static struct pci_dev *alim7101_pmu; | |
81 | ||
82 | static int nowayout = WATCHDOG_NOWAYOUT; | |
83 | module_param(nowayout, int, 0); | |
84 | MODULE_PARM_DESC(nowayout, | |
85 | "Watchdog cannot be stopped once started (default=" | |
86 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
87 | ||
88 | /* | |
89 | * Whack the dog | |
90 | */ | |
91 | ||
92 | static void wdt_timer_ping(unsigned long data) | |
93 | { | |
94 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL | |
95 | * we agree to ping the WDT | |
96 | */ | |
97 | char tmp; | |
98 | ||
99 | if (time_before(jiffies, next_heartbeat)) { | |
100 | /* Ping the WDT (this is actually a disarm/arm sequence) */ | |
101 | pci_read_config_byte(alim7101_pmu, 0x92, &tmp); | |
102 | pci_write_config_byte(alim7101_pmu, | |
103 | ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); | |
104 | pci_write_config_byte(alim7101_pmu, | |
105 | ALI_7101_WDT, (tmp | ALI_WDT_ARM)); | |
106 | if (use_gpio) { | |
107 | pci_read_config_byte(alim7101_pmu, | |
108 | ALI_7101_GPIO_O, &tmp); | |
109 | pci_write_config_byte(alim7101_pmu, | |
110 | ALI_7101_GPIO_O, tmp | 0x20); | |
111 | pci_write_config_byte(alim7101_pmu, | |
112 | ALI_7101_GPIO_O, tmp & ~0x20); | |
113 | } | |
114 | } else { | |
115 | printk(KERN_WARNING PFX | |
116 | "Heartbeat lost! Will not ping the watchdog\n"); | |
117 | } | |
118 | /* Re-set the timer interval */ | |
119 | mod_timer(&timer, jiffies + WDT_INTERVAL); | |
120 | } | |
121 | ||
122 | /* | |
123 | * Utility routines | |
124 | */ | |
125 | ||
126 | static void wdt_change(int writeval) | |
127 | { | |
128 | char tmp; | |
129 | ||
130 | pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp); | |
131 | if (writeval == WDT_ENABLE) { | |
132 | pci_write_config_byte(alim7101_pmu, | |
133 | ALI_7101_WDT, (tmp | ALI_WDT_ARM)); | |
134 | if (use_gpio) { | |
135 | pci_read_config_byte(alim7101_pmu, | |
136 | ALI_7101_GPIO_O, &tmp); | |
137 | pci_write_config_byte(alim7101_pmu, | |
138 | ALI_7101_GPIO_O, tmp & ~0x20); | |
139 | } | |
140 | ||
141 | } else { | |
142 | pci_write_config_byte(alim7101_pmu, | |
143 | ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); | |
144 | if (use_gpio) { | |
145 | pci_read_config_byte(alim7101_pmu, | |
146 | ALI_7101_GPIO_O, &tmp); | |
147 | pci_write_config_byte(alim7101_pmu, | |
148 | ALI_7101_GPIO_O, tmp | 0x20); | |
149 | } | |
150 | } | |
151 | } | |
152 | ||
153 | static void wdt_startup(void) | |
154 | { | |
155 | next_heartbeat = jiffies + (timeout * HZ); | |
156 | ||
157 | /* We must enable before we kick off the timer in case the timer | |
158 | occurs as we ping it */ | |
159 | ||
160 | wdt_change(WDT_ENABLE); | |
161 | ||
162 | /* Start the timer */ | |
163 | mod_timer(&timer, jiffies + WDT_INTERVAL); | |
164 | ||
165 | printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); | |
166 | } | |
167 | ||
168 | static void wdt_turnoff(void) | |
169 | { | |
170 | /* Stop the timer */ | |
171 | del_timer_sync(&timer); | |
172 | wdt_change(WDT_DISABLE); | |
173 | printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); | |
174 | } | |
175 | ||
176 | static void wdt_keepalive(void) | |
177 | { | |
178 | /* user land ping */ | |
179 | next_heartbeat = jiffies + (timeout * HZ); | |
180 | } | |
181 | ||
182 | /* | |
183 | * /dev/watchdog handling | |
184 | */ | |
185 | ||
186 | static ssize_t fop_write(struct file *file, const char __user *buf, | |
187 | size_t count, loff_t *ppos) | |
188 | { | |
189 | /* See if we got the magic character 'V' and reload the timer */ | |
190 | if (count) { | |
191 | if (!nowayout) { | |
192 | size_t ofs; | |
193 | ||
194 | /* note: just in case someone wrote the magic character | |
195 | * five months ago... */ | |
196 | wdt_expect_close = 0; | |
197 | ||
198 | /* now scan */ | |
199 | for (ofs = 0; ofs != count; ofs++) { | |
200 | char c; | |
201 | if (get_user(c, buf+ofs)) | |
202 | return -EFAULT; | |
203 | if (c == 'V') | |
204 | wdt_expect_close = 42; | |
205 | } | |
206 | } | |
207 | /* someone wrote to us, we should restart timer */ | |
208 | wdt_keepalive(); | |
209 | } | |
210 | return count; | |
211 | } | |
212 | ||
213 | static int fop_open(struct inode *inode, struct file *file) | |
214 | { | |
215 | /* Just in case we're already talking to someone... */ | |
216 | if (test_and_set_bit(0, &wdt_is_open)) | |
217 | return -EBUSY; | |
218 | /* Good, fire up the show */ | |
219 | wdt_startup(); | |
220 | return nonseekable_open(inode, file); | |
221 | } | |
222 | ||
223 | static int fop_close(struct inode *inode, struct file *file) | |
224 | { | |
225 | if (wdt_expect_close == 42) | |
226 | wdt_turnoff(); | |
227 | else { | |
228 | /* wim: shouldn't there be a: del_timer(&timer); */ | |
229 | printk(KERN_CRIT PFX | |
230 | "device file closed unexpectedly. Will not stop the WDT!\n"); | |
231 | } | |
232 | clear_bit(0, &wdt_is_open); | |
233 | wdt_expect_close = 0; | |
234 | return 0; | |
235 | } | |
236 | ||
237 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
238 | { | |
239 | void __user *argp = (void __user *)arg; | |
240 | int __user *p = argp; | |
241 | static struct watchdog_info ident = { | |
242 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | |
243 | | WDIOF_MAGICCLOSE, | |
244 | .firmware_version = 1, | |
245 | .identity = "ALiM7101", | |
246 | }; | |
247 | ||
248 | switch (cmd) { | |
249 | case WDIOC_GETSUPPORT: | |
250 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
251 | case WDIOC_GETSTATUS: | |
252 | case WDIOC_GETBOOTSTATUS: | |
253 | return put_user(0, p); | |
254 | case WDIOC_KEEPALIVE: | |
255 | wdt_keepalive(); | |
256 | return 0; | |
257 | case WDIOC_SETOPTIONS: | |
258 | { | |
259 | int new_options, retval = -EINVAL; | |
260 | ||
261 | if (get_user(new_options, p)) | |
262 | return -EFAULT; | |
263 | if (new_options & WDIOS_DISABLECARD) { | |
264 | wdt_turnoff(); | |
265 | retval = 0; | |
266 | } | |
267 | if (new_options & WDIOS_ENABLECARD) { | |
268 | wdt_startup(); | |
269 | retval = 0; | |
270 | } | |
271 | return retval; | |
272 | } | |
273 | case WDIOC_SETTIMEOUT: | |
274 | { | |
275 | int new_timeout; | |
276 | ||
277 | if (get_user(new_timeout, p)) | |
278 | return -EFAULT; | |
279 | /* arbitrary upper limit */ | |
280 | if (new_timeout < 1 || new_timeout > 3600) | |
281 | return -EINVAL; | |
282 | timeout = new_timeout; | |
283 | wdt_keepalive(); | |
284 | /* Fall through */ | |
285 | } | |
286 | case WDIOC_GETTIMEOUT: | |
287 | return put_user(timeout, p); | |
288 | default: | |
289 | return -ENOTTY; | |
290 | } | |
291 | } | |
292 | ||
293 | static const struct file_operations wdt_fops = { | |
294 | .owner = THIS_MODULE, | |
295 | .llseek = no_llseek, | |
296 | .write = fop_write, | |
297 | .open = fop_open, | |
298 | .release = fop_close, | |
299 | .unlocked_ioctl = fop_ioctl, | |
300 | }; | |
301 | ||
302 | static struct miscdevice wdt_miscdev = { | |
303 | .minor = WATCHDOG_MINOR, | |
304 | .name = "watchdog", | |
305 | .fops = &wdt_fops, | |
306 | }; | |
307 | ||
308 | /* | |
309 | * Notifier for system down | |
310 | */ | |
311 | ||
312 | static int wdt_notify_sys(struct notifier_block *this, | |
313 | unsigned long code, void *unused) | |
314 | { | |
315 | if (code == SYS_DOWN || code == SYS_HALT) | |
316 | wdt_turnoff(); | |
317 | ||
318 | if (code == SYS_RESTART) { | |
319 | /* | |
320 | * Cobalt devices have no way of rebooting themselves other | |
321 | * than getting the watchdog to pull reset, so we restart the | |
322 | * watchdog on reboot with no heartbeat | |
323 | */ | |
324 | wdt_change(WDT_ENABLE); | |
325 | printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n"); | |
326 | } | |
327 | return NOTIFY_DONE; | |
328 | } | |
329 | ||
330 | /* | |
331 | * The WDT needs to learn about soft shutdowns in order to | |
332 | * turn the timebomb registers off. | |
333 | */ | |
334 | ||
335 | static struct notifier_block wdt_notifier = { | |
336 | .notifier_call = wdt_notify_sys, | |
337 | }; | |
338 | ||
339 | static void __exit alim7101_wdt_unload(void) | |
340 | { | |
341 | wdt_turnoff(); | |
342 | /* Deregister */ | |
343 | misc_deregister(&wdt_miscdev); | |
344 | unregister_reboot_notifier(&wdt_notifier); | |
345 | pci_dev_put(alim7101_pmu); | |
346 | } | |
347 | ||
348 | static int __init alim7101_wdt_init(void) | |
349 | { | |
350 | int rc = -EBUSY; | |
351 | struct pci_dev *ali1543_south; | |
352 | char tmp; | |
353 | ||
354 | printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n"); | |
355 | alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101, | |
356 | NULL); | |
357 | if (!alim7101_pmu) { | |
358 | printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n"); | |
359 | return -EBUSY; | |
360 | } | |
361 | ||
362 | /* Set the WDT in the PMU to 1 second */ | |
363 | pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02); | |
364 | ||
365 | ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, | |
366 | NULL); | |
367 | if (!ali1543_south) { | |
368 | printk(KERN_INFO PFX | |
369 | "ALi 1543 South-Bridge not present - WDT not set\n"); | |
370 | goto err_out; | |
371 | } | |
372 | pci_read_config_byte(ali1543_south, 0x5e, &tmp); | |
373 | pci_dev_put(ali1543_south); | |
374 | if ((tmp & 0x1e) == 0x00) { | |
375 | if (!use_gpio) { | |
376 | printk(KERN_INFO PFX "Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n"); | |
377 | goto err_out; | |
378 | } | |
379 | nowayout = 1; | |
380 | } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) { | |
381 | printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n"); | |
382 | goto err_out; | |
383 | } | |
384 | ||
385 | if (timeout < 1 || timeout > 3600) { | |
386 | /* arbitrary upper limit */ | |
387 | timeout = WATCHDOG_TIMEOUT; | |
388 | printk(KERN_INFO PFX | |
389 | "timeout value must be 1 <= x <= 3600, using %d\n", | |
390 | timeout); | |
391 | } | |
392 | ||
393 | rc = register_reboot_notifier(&wdt_notifier); | |
394 | if (rc) { | |
395 | printk(KERN_ERR PFX | |
396 | "cannot register reboot notifier (err=%d)\n", rc); | |
397 | goto err_out; | |
398 | } | |
399 | ||
400 | rc = misc_register(&wdt_miscdev); | |
401 | if (rc) { | |
402 | printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", | |
403 | wdt_miscdev.minor, rc); | |
404 | goto err_out_reboot; | |
405 | } | |
406 | ||
407 | if (nowayout) | |
408 | __module_get(THIS_MODULE); | |
409 | ||
410 | printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n", | |
411 | timeout, nowayout); | |
412 | return 0; | |
413 | ||
414 | err_out_reboot: | |
415 | unregister_reboot_notifier(&wdt_notifier); | |
416 | err_out: | |
417 | pci_dev_put(alim7101_pmu); | |
418 | return rc; | |
419 | } | |
420 | ||
421 | module_init(alim7101_wdt_init); | |
422 | module_exit(alim7101_wdt_unload); | |
423 | ||
424 | static struct pci_device_id alim7101_pci_tbl[] __devinitdata = { | |
425 | { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) }, | |
426 | { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) }, | |
427 | { } | |
428 | }; | |
429 | ||
430 | MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl); | |
431 | ||
432 | MODULE_AUTHOR("Steve Hill"); | |
433 | MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver"); | |
434 | MODULE_LICENSE("GPL"); | |
435 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |