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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 | #include <linux/io.h> |
35 | #include <linux/uaccess.h> |
36 | |
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 const 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_SETOPTIONS: |
255 | { |
256 | int new_options, retval = -EINVAL; |
257 | |
258 | if (get_user(new_options, p)) |
259 | return -EFAULT; |
260 | if (new_options & WDIOS_DISABLECARD) { |
261 | wdt_turnoff(); |
262 | retval = 0; |
263 | } |
264 | if (new_options & WDIOS_ENABLECARD) { |
265 | wdt_startup(); |
266 | retval = 0; |
267 | } |
268 | return retval; |
269 | } |
270 | case WDIOC_KEEPALIVE: |
271 | wdt_keepalive(); |
272 | return 0; |
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 " |
326 | "with no heartbeat - should reboot in ~1 second.\n"); |
327 | } |
328 | return NOTIFY_DONE; |
329 | } |
330 | |
331 | /* |
332 | * The WDT needs to learn about soft shutdowns in order to |
333 | * turn the timebomb registers off. |
334 | */ |
335 | |
336 | static struct notifier_block wdt_notifier = { |
337 | .notifier_call = wdt_notify_sys, |
338 | }; |
339 | |
340 | static void __exit alim7101_wdt_unload(void) |
341 | { |
342 | wdt_turnoff(); |
343 | /* Deregister */ |
344 | misc_deregister(&wdt_miscdev); |
345 | unregister_reboot_notifier(&wdt_notifier); |
346 | pci_dev_put(alim7101_pmu); |
347 | } |
348 | |
349 | static int __init alim7101_wdt_init(void) |
350 | { |
351 | int rc = -EBUSY; |
352 | struct pci_dev *ali1543_south; |
353 | char tmp; |
354 | |
355 | printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n"); |
356 | alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101, |
357 | NULL); |
358 | if (!alim7101_pmu) { |
359 | printk(KERN_INFO PFX |
360 | "ALi M7101 PMU not present - WDT not set\n"); |
361 | return -EBUSY; |
362 | } |
363 | |
364 | /* Set the WDT in the PMU to 1 second */ |
365 | pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02); |
366 | |
367 | ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, |
368 | NULL); |
369 | if (!ali1543_south) { |
370 | printk(KERN_INFO PFX |
371 | "ALi 1543 South-Bridge not present - WDT not set\n"); |
372 | goto err_out; |
373 | } |
374 | pci_read_config_byte(ali1543_south, 0x5e, &tmp); |
375 | pci_dev_put(ali1543_south); |
376 | if ((tmp & 0x1e) == 0x00) { |
377 | if (!use_gpio) { |
378 | printk(KERN_INFO PFX |
379 | "Detected old alim7101 revision 'a1d'. " |
380 | "If this is a cobalt board, set the 'use_gpio' " |
381 | "module parameter.\n"); |
382 | goto err_out; |
383 | } |
384 | nowayout = 1; |
385 | } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) { |
386 | printk(KERN_INFO PFX |
387 | "ALi 1543 South-Bridge does not have the correct " |
388 | "revision number (???1001?) - WDT not set\n"); |
389 | goto err_out; |
390 | } |
391 | |
392 | if (timeout < 1 || timeout > 3600) { |
393 | /* arbitrary upper limit */ |
394 | timeout = WATCHDOG_TIMEOUT; |
395 | printk(KERN_INFO PFX |
396 | "timeout value must be 1 <= x <= 3600, using %d\n", |
397 | timeout); |
398 | } |
399 | |
400 | rc = register_reboot_notifier(&wdt_notifier); |
401 | if (rc) { |
402 | printk(KERN_ERR PFX |
403 | "cannot register reboot notifier (err=%d)\n", rc); |
404 | goto err_out; |
405 | } |
406 | |
407 | rc = misc_register(&wdt_miscdev); |
408 | if (rc) { |
409 | printk(KERN_ERR PFX |
410 | "cannot register miscdev on minor=%d (err=%d)\n", |
411 | wdt_miscdev.minor, rc); |
412 | goto err_out_reboot; |
413 | } |
414 | |
415 | if (nowayout) |
416 | __module_get(THIS_MODULE); |
417 | |
418 | printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. " |
419 | "timeout=%d sec (nowayout=%d)\n", |
420 | timeout, nowayout); |
421 | return 0; |
422 | |
423 | err_out_reboot: |
424 | unregister_reboot_notifier(&wdt_notifier); |
425 | err_out: |
426 | pci_dev_put(alim7101_pmu); |
427 | return rc; |
428 | } |
429 | |
430 | module_init(alim7101_wdt_init); |
431 | module_exit(alim7101_wdt_unload); |
432 | |
433 | static struct pci_device_id alim7101_pci_tbl[] __devinitdata = { |
434 | { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) }, |
435 | { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) }, |
436 | { } |
437 | }; |
438 | |
439 | MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl); |
440 | |
441 | MODULE_AUTHOR("Steve Hill"); |
442 | MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver"); |
443 | MODULE_LICENSE("GPL"); |
444 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
445 |
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