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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 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
23 | |
24 | #include <linux/module.h> |
25 | #include <linux/moduleparam.h> |
26 | #include <linux/types.h> |
27 | #include <linux/timer.h> |
28 | #include <linux/miscdevice.h> |
29 | #include <linux/watchdog.h> |
30 | #include <linux/ioport.h> |
31 | #include <linux/notifier.h> |
32 | #include <linux/reboot.h> |
33 | #include <linux/init.h> |
34 | #include <linux/fs.h> |
35 | #include <linux/pci.h> |
36 | #include <linux/io.h> |
37 | #include <linux/uaccess.h> |
38 | |
39 | |
40 | #define WDT_ENABLE 0x9C |
41 | #define WDT_DISABLE 0x8C |
42 | |
43 | #define ALI_7101_WDT 0x92 |
44 | #define ALI_7101_GPIO 0x7D |
45 | #define ALI_7101_GPIO_O 0x7E |
46 | #define ALI_WDT_ARM 0x01 |
47 | |
48 | /* |
49 | * We're going to use a 1 second timeout. |
50 | * If we reset the watchdog every ~250ms we should be safe. */ |
51 | |
52 | #define WDT_INTERVAL (HZ/4+1) |
53 | |
54 | /* |
55 | * We must not require too good response from the userspace daemon. |
56 | * Here we require the userspace daemon to send us a heartbeat |
57 | * char to /dev/watchdog every 30 seconds. |
58 | */ |
59 | |
60 | #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ |
61 | /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ |
62 | static int timeout = WATCHDOG_TIMEOUT; |
63 | module_param(timeout, int, 0); |
64 | MODULE_PARM_DESC(timeout, |
65 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" |
66 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
67 | |
68 | static int use_gpio; /* Use the pic (for a1d revision alim7101) */ |
69 | module_param(use_gpio, int, 0); |
70 | MODULE_PARM_DESC(use_gpio, |
71 | "Use the gpio watchdog (required by old cobalt boards)."); |
72 | |
73 | static void wdt_timer_ping(unsigned long); |
74 | static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1); |
75 | static unsigned long next_heartbeat; |
76 | static unsigned long wdt_is_open; |
77 | static char wdt_expect_close; |
78 | static struct pci_dev *alim7101_pmu; |
79 | |
80 | static bool nowayout = WATCHDOG_NOWAYOUT; |
81 | module_param(nowayout, bool, 0); |
82 | MODULE_PARM_DESC(nowayout, |
83 | "Watchdog cannot be stopped once started (default=" |
84 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
85 | |
86 | /* |
87 | * Whack the dog |
88 | */ |
89 | |
90 | static void wdt_timer_ping(unsigned long data) |
91 | { |
92 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL |
93 | * we agree to ping the WDT |
94 | */ |
95 | char tmp; |
96 | |
97 | if (time_before(jiffies, next_heartbeat)) { |
98 | /* Ping the WDT (this is actually a disarm/arm sequence) */ |
99 | pci_read_config_byte(alim7101_pmu, 0x92, &tmp); |
100 | pci_write_config_byte(alim7101_pmu, |
101 | ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); |
102 | pci_write_config_byte(alim7101_pmu, |
103 | ALI_7101_WDT, (tmp | ALI_WDT_ARM)); |
104 | if (use_gpio) { |
105 | pci_read_config_byte(alim7101_pmu, |
106 | ALI_7101_GPIO_O, &tmp); |
107 | pci_write_config_byte(alim7101_pmu, |
108 | ALI_7101_GPIO_O, tmp | 0x20); |
109 | pci_write_config_byte(alim7101_pmu, |
110 | ALI_7101_GPIO_O, tmp & ~0x20); |
111 | } |
112 | } else { |
113 | pr_warn("Heartbeat lost! Will not ping the watchdog\n"); |
114 | } |
115 | /* Re-set the timer interval */ |
116 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
117 | } |
118 | |
119 | /* |
120 | * Utility routines |
121 | */ |
122 | |
123 | static void wdt_change(int writeval) |
124 | { |
125 | char tmp; |
126 | |
127 | pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp); |
128 | if (writeval == WDT_ENABLE) { |
129 | pci_write_config_byte(alim7101_pmu, |
130 | ALI_7101_WDT, (tmp | ALI_WDT_ARM)); |
131 | if (use_gpio) { |
132 | pci_read_config_byte(alim7101_pmu, |
133 | ALI_7101_GPIO_O, &tmp); |
134 | pci_write_config_byte(alim7101_pmu, |
135 | ALI_7101_GPIO_O, tmp & ~0x20); |
136 | } |
137 | |
138 | } else { |
139 | pci_write_config_byte(alim7101_pmu, |
140 | ALI_7101_WDT, (tmp & ~ALI_WDT_ARM)); |
141 | if (use_gpio) { |
142 | pci_read_config_byte(alim7101_pmu, |
143 | ALI_7101_GPIO_O, &tmp); |
144 | pci_write_config_byte(alim7101_pmu, |
145 | ALI_7101_GPIO_O, tmp | 0x20); |
146 | } |
147 | } |
148 | } |
149 | |
150 | static void wdt_startup(void) |
151 | { |
152 | next_heartbeat = jiffies + (timeout * HZ); |
153 | |
154 | /* We must enable before we kick off the timer in case the timer |
155 | occurs as we ping it */ |
156 | |
157 | wdt_change(WDT_ENABLE); |
158 | |
159 | /* Start the timer */ |
160 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
161 | |
162 | pr_info("Watchdog timer is now enabled\n"); |
163 | } |
164 | |
165 | static void wdt_turnoff(void) |
166 | { |
167 | /* Stop the timer */ |
168 | del_timer_sync(&timer); |
169 | wdt_change(WDT_DISABLE); |
170 | pr_info("Watchdog timer is now disabled...\n"); |
171 | } |
172 | |
173 | static void wdt_keepalive(void) |
174 | { |
175 | /* user land ping */ |
176 | next_heartbeat = jiffies + (timeout * HZ); |
177 | } |
178 | |
179 | /* |
180 | * /dev/watchdog handling |
181 | */ |
182 | |
183 | static ssize_t fop_write(struct file *file, const char __user *buf, |
184 | size_t count, loff_t *ppos) |
185 | { |
186 | /* See if we got the magic character 'V' and reload the timer */ |
187 | if (count) { |
188 | if (!nowayout) { |
189 | size_t ofs; |
190 | |
191 | /* note: just in case someone wrote the magic character |
192 | * five months ago... */ |
193 | wdt_expect_close = 0; |
194 | |
195 | /* now scan */ |
196 | for (ofs = 0; ofs != count; ofs++) { |
197 | char c; |
198 | if (get_user(c, buf + ofs)) |
199 | return -EFAULT; |
200 | if (c == 'V') |
201 | wdt_expect_close = 42; |
202 | } |
203 | } |
204 | /* someone wrote to us, we should restart timer */ |
205 | wdt_keepalive(); |
206 | } |
207 | return count; |
208 | } |
209 | |
210 | static int fop_open(struct inode *inode, struct file *file) |
211 | { |
212 | /* Just in case we're already talking to someone... */ |
213 | if (test_and_set_bit(0, &wdt_is_open)) |
214 | return -EBUSY; |
215 | /* Good, fire up the show */ |
216 | wdt_startup(); |
217 | return nonseekable_open(inode, file); |
218 | } |
219 | |
220 | static int fop_close(struct inode *inode, struct file *file) |
221 | { |
222 | if (wdt_expect_close == 42) |
223 | wdt_turnoff(); |
224 | else { |
225 | /* wim: shouldn't there be a: del_timer(&timer); */ |
226 | pr_crit("device file closed unexpectedly. Will not stop the WDT!\n"); |
227 | } |
228 | clear_bit(0, &wdt_is_open); |
229 | wdt_expect_close = 0; |
230 | return 0; |
231 | } |
232 | |
233 | static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
234 | { |
235 | void __user *argp = (void __user *)arg; |
236 | int __user *p = argp; |
237 | static const struct watchdog_info ident = { |
238 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
239 | | WDIOF_MAGICCLOSE, |
240 | .firmware_version = 1, |
241 | .identity = "ALiM7101", |
242 | }; |
243 | |
244 | switch (cmd) { |
245 | case WDIOC_GETSUPPORT: |
246 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
247 | case WDIOC_GETSTATUS: |
248 | case WDIOC_GETBOOTSTATUS: |
249 | return put_user(0, p); |
250 | case WDIOC_SETOPTIONS: |
251 | { |
252 | int new_options, retval = -EINVAL; |
253 | |
254 | if (get_user(new_options, p)) |
255 | return -EFAULT; |
256 | if (new_options & WDIOS_DISABLECARD) { |
257 | wdt_turnoff(); |
258 | retval = 0; |
259 | } |
260 | if (new_options & WDIOS_ENABLECARD) { |
261 | wdt_startup(); |
262 | retval = 0; |
263 | } |
264 | return retval; |
265 | } |
266 | case WDIOC_KEEPALIVE: |
267 | wdt_keepalive(); |
268 | return 0; |
269 | case WDIOC_SETTIMEOUT: |
270 | { |
271 | int new_timeout; |
272 | |
273 | if (get_user(new_timeout, p)) |
274 | return -EFAULT; |
275 | /* arbitrary upper limit */ |
276 | if (new_timeout < 1 || new_timeout > 3600) |
277 | return -EINVAL; |
278 | timeout = new_timeout; |
279 | wdt_keepalive(); |
280 | /* Fall through */ |
281 | } |
282 | case WDIOC_GETTIMEOUT: |
283 | return put_user(timeout, p); |
284 | default: |
285 | return -ENOTTY; |
286 | } |
287 | } |
288 | |
289 | static const struct file_operations wdt_fops = { |
290 | .owner = THIS_MODULE, |
291 | .llseek = no_llseek, |
292 | .write = fop_write, |
293 | .open = fop_open, |
294 | .release = fop_close, |
295 | .unlocked_ioctl = fop_ioctl, |
296 | }; |
297 | |
298 | static struct miscdevice wdt_miscdev = { |
299 | .minor = WATCHDOG_MINOR, |
300 | .name = "watchdog", |
301 | .fops = &wdt_fops, |
302 | }; |
303 | |
304 | /* |
305 | * Notifier for system down |
306 | */ |
307 | |
308 | static int wdt_notify_sys(struct notifier_block *this, |
309 | unsigned long code, void *unused) |
310 | { |
311 | if (code == SYS_DOWN || code == SYS_HALT) |
312 | wdt_turnoff(); |
313 | |
314 | if (code == SYS_RESTART) { |
315 | /* |
316 | * Cobalt devices have no way of rebooting themselves other |
317 | * than getting the watchdog to pull reset, so we restart the |
318 | * watchdog on reboot with no heartbeat |
319 | */ |
320 | wdt_change(WDT_ENABLE); |
321 | pr_info("Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second\n"); |
322 | } |
323 | return NOTIFY_DONE; |
324 | } |
325 | |
326 | /* |
327 | * The WDT needs to learn about soft shutdowns in order to |
328 | * turn the timebomb registers off. |
329 | */ |
330 | |
331 | static struct notifier_block wdt_notifier = { |
332 | .notifier_call = wdt_notify_sys, |
333 | }; |
334 | |
335 | static void __exit alim7101_wdt_unload(void) |
336 | { |
337 | wdt_turnoff(); |
338 | /* Deregister */ |
339 | misc_deregister(&wdt_miscdev); |
340 | unregister_reboot_notifier(&wdt_notifier); |
341 | pci_dev_put(alim7101_pmu); |
342 | } |
343 | |
344 | static int __init alim7101_wdt_init(void) |
345 | { |
346 | int rc = -EBUSY; |
347 | struct pci_dev *ali1543_south; |
348 | char tmp; |
349 | |
350 | pr_info("Steve Hill <steve@navaho.co.uk>\n"); |
351 | alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101, |
352 | NULL); |
353 | if (!alim7101_pmu) { |
354 | pr_info("ALi M7101 PMU not present - WDT not set\n"); |
355 | return -EBUSY; |
356 | } |
357 | |
358 | /* Set the WDT in the PMU to 1 second */ |
359 | pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02); |
360 | |
361 | ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, |
362 | NULL); |
363 | if (!ali1543_south) { |
364 | pr_info("ALi 1543 South-Bridge not present - WDT not set\n"); |
365 | goto err_out; |
366 | } |
367 | pci_read_config_byte(ali1543_south, 0x5e, &tmp); |
368 | pci_dev_put(ali1543_south); |
369 | if ((tmp & 0x1e) == 0x00) { |
370 | if (!use_gpio) { |
371 | pr_info("Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n"); |
372 | goto err_out; |
373 | } |
374 | nowayout = 1; |
375 | } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) { |
376 | pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n"); |
377 | goto err_out; |
378 | } |
379 | |
380 | if (timeout < 1 || timeout > 3600) { |
381 | /* arbitrary upper limit */ |
382 | timeout = WATCHDOG_TIMEOUT; |
383 | pr_info("timeout value must be 1 <= x <= 3600, using %d\n", |
384 | timeout); |
385 | } |
386 | |
387 | rc = register_reboot_notifier(&wdt_notifier); |
388 | if (rc) { |
389 | pr_err("cannot register reboot notifier (err=%d)\n", rc); |
390 | goto err_out; |
391 | } |
392 | |
393 | rc = misc_register(&wdt_miscdev); |
394 | if (rc) { |
395 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
396 | wdt_miscdev.minor, rc); |
397 | goto err_out_reboot; |
398 | } |
399 | |
400 | if (nowayout) |
401 | __module_get(THIS_MODULE); |
402 | |
403 | pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n", |
404 | timeout, nowayout); |
405 | return 0; |
406 | |
407 | err_out_reboot: |
408 | unregister_reboot_notifier(&wdt_notifier); |
409 | err_out: |
410 | pci_dev_put(alim7101_pmu); |
411 | return rc; |
412 | } |
413 | |
414 | module_init(alim7101_wdt_init); |
415 | module_exit(alim7101_wdt_unload); |
416 | |
417 | static DEFINE_PCI_DEVICE_TABLE(alim7101_pci_tbl) __used = { |
418 | { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) }, |
419 | { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) }, |
420 | { } |
421 | }; |
422 | |
423 | MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl); |
424 | |
425 | MODULE_AUTHOR("Steve Hill"); |
426 | MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver"); |
427 | MODULE_LICENSE("GPL"); |
428 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
429 |
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