Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * AMD Elan SC520 processor Watchdog Timer driver | |
3 | * | |
4 | * Based on acquirewdt.c by Alan Cox, | |
5 | * and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version | |
10 | * 2 of the License, or (at your option) any later version. | |
11 | * | |
12 | * The authors do NOT admit liability nor provide warranty for | |
13 | * any of this software. This material is provided "AS-IS" in | |
14 | * the hope that it may be useful for others. | |
15 | * | |
16 | * (c) Copyright 2001 Scott Jennings <linuxdrivers@oro.net> | |
17 | * 9/27 - 2001 [Initial release] | |
18 | * | |
19 | * Additional fixes Alan Cox | |
20 | * - Fixed formatting | |
21 | * - Removed debug printks | |
22 | * - Fixed SMP built kernel deadlock | |
23 | * - Switched to private locks not lock_kernel | |
24 | * - Used ioremap/writew/readw | |
25 | * - Added NOWAYOUT support | |
26 | * 4/12 - 2002 Changes by Rob Radez <rob@osinvestor.com> | |
27 | * - Change comments | |
28 | * - Eliminate fop_llseek | |
29 | * - Change CONFIG_WATCHDOG_NOWAYOUT semantics | |
30 | * - Add KERN_* tags to printks | |
31 | * - fix possible wdt_is_open race | |
32 | * - Report proper capabilities in watchdog_info | |
33 | * - Add WDIOC_{GETSTATUS, GETBOOTSTATUS, SETTIMEOUT, | |
34 | * GETTIMEOUT, SETOPTIONS} ioctls | |
35 | * 09/8 - 2003 Changes by Wim Van Sebroeck <wim@iguana.be> | |
36 | * - cleanup of trailing spaces | |
37 | * - added extra printk's for startup problems | |
38 | * - use module_param | |
39 | * - made timeout (the emulated heartbeat) a module_param | |
40 | * - made the keepalive ping an internal subroutine | |
41 | * 3/27 - 2004 Changes by Sean Young <sean@mess.org> | |
42 | * - set MMCR_BASE to 0xfffef000 | |
43 | * - CBAR does not need to be read | |
44 | * - removed debugging printks | |
45 | * | |
46 | * This WDT driver is different from most other Linux WDT | |
47 | * drivers in that the driver will ping the watchdog by itself, | |
48 | * because this particular WDT has a very short timeout (1.6 | |
49 | * seconds) and it would be insane to count on any userspace | |
50 | * daemon always getting scheduled within that time frame. | |
51 | * | |
52 | * This driver uses memory mapped IO, and spinlock. | |
53 | */ | |
54 | ||
55 | #include <linux/module.h> | |
56 | #include <linux/moduleparam.h> | |
57 | #include <linux/types.h> | |
58 | #include <linux/timer.h> | |
59 | #include <linux/miscdevice.h> | |
60 | #include <linux/watchdog.h> | |
61 | #include <linux/fs.h> | |
62 | #include <linux/ioport.h> | |
63 | #include <linux/notifier.h> | |
64 | #include <linux/reboot.h> | |
65 | #include <linux/init.h> | |
4e57b681 | 66 | #include <linux/jiffies.h> |
1da177e4 LT |
67 | |
68 | #include <asm/io.h> | |
69 | #include <asm/uaccess.h> | |
70 | #include <asm/system.h> | |
71 | ||
72 | #define OUR_NAME "sc520_wdt" | |
73 | #define PFX OUR_NAME ": " | |
74 | ||
75 | /* | |
76 | * The AMD Elan SC520 timeout value is 492us times a power of 2 (0-7) | |
77 | * | |
78 | * 0: 492us 2: 1.01s 4: 4.03s 6: 16.22s | |
79 | * 1: 503ms 3: 2.01s 5: 8.05s 7: 32.21s | |
80 | * | |
81 | * We will program the SC520 watchdog for a timeout of 2.01s. | |
82 | * If we reset the watchdog every ~250ms we should be safe. | |
83 | */ | |
84 | ||
85 | #define WDT_INTERVAL (HZ/4+1) | |
86 | ||
87 | /* | |
88 | * We must not require too good response from the userspace daemon. | |
89 | * Here we require the userspace daemon to send us a heartbeat | |
90 | * char to /dev/watchdog every 30 seconds. | |
91 | */ | |
92 | ||
93 | #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ | |
94 | static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ | |
95 | module_param(timeout, int, 0); | |
96 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
97 | ||
4bfdf378 | 98 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 | 99 | module_param(nowayout, int, 0); |
bffda5c8 | 100 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
1da177e4 LT |
101 | |
102 | /* | |
103 | * AMD Elan SC520 - Watchdog Timer Registers | |
104 | */ | |
105 | #define MMCR_BASE 0xfffef000 /* The default base address */ | |
106 | #define OFFS_WDTMRCTL 0xCB0 /* Watchdog Timer Control Register */ | |
107 | ||
108 | /* WDT Control Register bit definitions */ | |
109 | #define WDT_EXP_SEL_01 0x0001 /* [01] Time-out = 496 us (with 33 Mhz clk). */ | |
110 | #define WDT_EXP_SEL_02 0x0002 /* [02] Time-out = 508 ms (with 33 Mhz clk). */ | |
111 | #define WDT_EXP_SEL_03 0x0004 /* [03] Time-out = 1.02 s (with 33 Mhz clk). */ | |
112 | #define WDT_EXP_SEL_04 0x0008 /* [04] Time-out = 2.03 s (with 33 Mhz clk). */ | |
113 | #define WDT_EXP_SEL_05 0x0010 /* [05] Time-out = 4.07 s (with 33 Mhz clk). */ | |
114 | #define WDT_EXP_SEL_06 0x0020 /* [06] Time-out = 8.13 s (with 33 Mhz clk). */ | |
115 | #define WDT_EXP_SEL_07 0x0040 /* [07] Time-out = 16.27s (with 33 Mhz clk). */ | |
116 | #define WDT_EXP_SEL_08 0x0080 /* [08] Time-out = 32.54s (with 33 Mhz clk). */ | |
117 | #define WDT_IRQ_FLG 0x1000 /* [12] Interrupt Request Flag */ | |
118 | #define WDT_WRST_ENB 0x4000 /* [14] Watchdog Timer Reset Enable */ | |
119 | #define WDT_ENB 0x8000 /* [15] Watchdog Timer Enable */ | |
120 | ||
121 | static __u16 __iomem *wdtmrctl; | |
122 | ||
123 | static void wdt_timer_ping(unsigned long); | |
82eb7c50 | 124 | static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0); |
1da177e4 LT |
125 | static unsigned long next_heartbeat; |
126 | static unsigned long wdt_is_open; | |
127 | static char wdt_expect_close; | |
128 | static spinlock_t wdt_spinlock; | |
129 | ||
130 | /* | |
131 | * Whack the dog | |
132 | */ | |
133 | ||
134 | static void wdt_timer_ping(unsigned long data) | |
135 | { | |
136 | /* If we got a heartbeat pulse within the WDT_US_INTERVAL | |
137 | * we agree to ping the WDT | |
138 | */ | |
139 | if(time_before(jiffies, next_heartbeat)) | |
140 | { | |
141 | /* Ping the WDT */ | |
142 | spin_lock(&wdt_spinlock); | |
143 | writew(0xAAAA, wdtmrctl); | |
144 | writew(0x5555, wdtmrctl); | |
145 | spin_unlock(&wdt_spinlock); | |
146 | ||
147 | /* Re-set the timer interval */ | |
82eb7c50 | 148 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
1da177e4 LT |
149 | } else { |
150 | printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n"); | |
151 | } | |
152 | } | |
153 | ||
154 | /* | |
155 | * Utility routines | |
156 | */ | |
157 | ||
158 | static void wdt_config(int writeval) | |
159 | { | |
160 | __u16 dummy; | |
161 | unsigned long flags; | |
162 | ||
163 | /* buy some time (ping) */ | |
164 | spin_lock_irqsave(&wdt_spinlock, flags); | |
165 | dummy=readw(wdtmrctl); /* ensure write synchronization */ | |
166 | writew(0xAAAA, wdtmrctl); | |
167 | writew(0x5555, wdtmrctl); | |
168 | /* unlock WDT = make WDT configuration register writable one time */ | |
169 | writew(0x3333, wdtmrctl); | |
170 | writew(0xCCCC, wdtmrctl); | |
171 | /* write WDT configuration register */ | |
172 | writew(writeval, wdtmrctl); | |
173 | spin_unlock_irqrestore(&wdt_spinlock, flags); | |
174 | } | |
175 | ||
176 | static int wdt_startup(void) | |
177 | { | |
178 | next_heartbeat = jiffies + (timeout * HZ); | |
179 | ||
180 | /* Start the timer */ | |
82eb7c50 | 181 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
1da177e4 LT |
182 | |
183 | /* Start the watchdog */ | |
184 | wdt_config(WDT_ENB | WDT_WRST_ENB | WDT_EXP_SEL_04); | |
185 | ||
186 | printk(KERN_INFO PFX "Watchdog timer is now enabled.\n"); | |
187 | return 0; | |
188 | } | |
189 | ||
190 | static int wdt_turnoff(void) | |
191 | { | |
192 | /* Stop the timer */ | |
193 | del_timer(&timer); | |
194 | ||
195 | /* Stop the watchdog */ | |
196 | wdt_config(0); | |
197 | ||
198 | printk(KERN_INFO PFX "Watchdog timer is now disabled...\n"); | |
199 | return 0; | |
200 | } | |
201 | ||
202 | static int wdt_keepalive(void) | |
203 | { | |
204 | /* user land ping */ | |
205 | next_heartbeat = jiffies + (timeout * HZ); | |
206 | return 0; | |
207 | } | |
208 | ||
209 | static int wdt_set_heartbeat(int t) | |
210 | { | |
211 | if ((t < 1) || (t > 3600)) /* arbitrary upper limit */ | |
212 | return -EINVAL; | |
213 | ||
214 | timeout = t; | |
215 | return 0; | |
216 | } | |
217 | ||
218 | /* | |
219 | * /dev/watchdog handling | |
220 | */ | |
221 | ||
222 | static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos) | |
223 | { | |
224 | /* See if we got the magic character 'V' and reload the timer */ | |
225 | if(count) { | |
226 | if (!nowayout) { | |
227 | size_t ofs; | |
228 | ||
229 | /* note: just in case someone wrote the magic character | |
230 | * five months ago... */ | |
231 | wdt_expect_close = 0; | |
232 | ||
233 | /* now scan */ | |
234 | for(ofs = 0; ofs != count; ofs++) { | |
235 | char c; | |
236 | if (get_user(c, buf + ofs)) | |
237 | return -EFAULT; | |
238 | if(c == 'V') | |
239 | wdt_expect_close = 42; | |
240 | } | |
241 | } | |
242 | ||
243 | /* Well, anyhow someone wrote to us, we should return that favour */ | |
244 | wdt_keepalive(); | |
245 | } | |
246 | return count; | |
247 | } | |
248 | ||
249 | static int fop_open(struct inode * inode, struct file * file) | |
250 | { | |
1da177e4 LT |
251 | /* Just in case we're already talking to someone... */ |
252 | if(test_and_set_bit(0, &wdt_is_open)) | |
253 | return -EBUSY; | |
254 | if (nowayout) | |
255 | __module_get(THIS_MODULE); | |
256 | ||
257 | /* Good, fire up the show */ | |
258 | wdt_startup(); | |
6abe78bf | 259 | return nonseekable_open(inode, file); |
1da177e4 LT |
260 | } |
261 | ||
262 | static int fop_close(struct inode * inode, struct file * file) | |
263 | { | |
264 | if(wdt_expect_close == 42) { | |
265 | wdt_turnoff(); | |
266 | } else { | |
267 | printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); | |
268 | wdt_keepalive(); | |
269 | } | |
270 | clear_bit(0, &wdt_is_open); | |
271 | wdt_expect_close = 0; | |
272 | return 0; | |
273 | } | |
274 | ||
275 | static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
276 | unsigned long arg) | |
277 | { | |
278 | void __user *argp = (void __user *)arg; | |
279 | int __user *p = argp; | |
280 | static struct watchdog_info ident = { | |
281 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, | |
282 | .firmware_version = 1, | |
283 | .identity = "SC520", | |
284 | }; | |
285 | ||
286 | switch(cmd) | |
287 | { | |
288 | default: | |
795b89d2 | 289 | return -ENOTTY; |
1da177e4 LT |
290 | case WDIOC_GETSUPPORT: |
291 | return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0; | |
292 | case WDIOC_GETSTATUS: | |
293 | case WDIOC_GETBOOTSTATUS: | |
294 | return put_user(0, p); | |
295 | case WDIOC_KEEPALIVE: | |
296 | wdt_keepalive(); | |
297 | return 0; | |
298 | case WDIOC_SETOPTIONS: | |
299 | { | |
300 | int new_options, retval = -EINVAL; | |
301 | ||
302 | if(get_user(new_options, p)) | |
303 | return -EFAULT; | |
304 | ||
305 | if(new_options & WDIOS_DISABLECARD) { | |
306 | wdt_turnoff(); | |
307 | retval = 0; | |
308 | } | |
309 | ||
310 | if(new_options & WDIOS_ENABLECARD) { | |
311 | wdt_startup(); | |
312 | retval = 0; | |
313 | } | |
314 | ||
315 | return retval; | |
316 | } | |
317 | case WDIOC_SETTIMEOUT: | |
318 | { | |
319 | int new_timeout; | |
320 | ||
321 | if(get_user(new_timeout, p)) | |
322 | return -EFAULT; | |
323 | ||
324 | if(wdt_set_heartbeat(new_timeout)) | |
325 | return -EINVAL; | |
326 | ||
327 | wdt_keepalive(); | |
328 | /* Fall through */ | |
329 | } | |
330 | case WDIOC_GETTIMEOUT: | |
331 | return put_user(timeout, p); | |
332 | } | |
333 | } | |
334 | ||
62322d25 | 335 | static const struct file_operations wdt_fops = { |
1da177e4 LT |
336 | .owner = THIS_MODULE, |
337 | .llseek = no_llseek, | |
338 | .write = fop_write, | |
339 | .open = fop_open, | |
340 | .release = fop_close, | |
341 | .ioctl = fop_ioctl, | |
342 | }; | |
343 | ||
344 | static struct miscdevice wdt_miscdev = { | |
345 | .minor = WATCHDOG_MINOR, | |
346 | .name = "watchdog", | |
347 | .fops = &wdt_fops, | |
348 | }; | |
349 | ||
350 | /* | |
351 | * Notifier for system down | |
352 | */ | |
353 | ||
354 | static int wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
355 | void *unused) | |
356 | { | |
357 | if(code==SYS_DOWN || code==SYS_HALT) | |
358 | wdt_turnoff(); | |
359 | return NOTIFY_DONE; | |
360 | } | |
361 | ||
362 | /* | |
363 | * The WDT needs to learn about soft shutdowns in order to | |
364 | * turn the timebomb registers off. | |
365 | */ | |
366 | ||
367 | static struct notifier_block wdt_notifier = { | |
368 | .notifier_call = wdt_notify_sys, | |
369 | }; | |
370 | ||
371 | static void __exit sc520_wdt_unload(void) | |
372 | { | |
373 | if (!nowayout) | |
374 | wdt_turnoff(); | |
375 | ||
376 | /* Deregister */ | |
377 | misc_deregister(&wdt_miscdev); | |
378 | unregister_reboot_notifier(&wdt_notifier); | |
379 | iounmap(wdtmrctl); | |
380 | } | |
381 | ||
382 | static int __init sc520_wdt_init(void) | |
383 | { | |
384 | int rc = -EBUSY; | |
385 | ||
386 | spin_lock_init(&wdt_spinlock); | |
387 | ||
1da177e4 LT |
388 | /* Check that the timeout value is within it's range ; if not reset to the default */ |
389 | if (wdt_set_heartbeat(timeout)) { | |
390 | wdt_set_heartbeat(WATCHDOG_TIMEOUT); | |
391 | printk(KERN_INFO PFX "timeout value must be 1<=timeout<=3600, using %d\n", | |
392 | WATCHDOG_TIMEOUT); | |
393 | } | |
394 | ||
395 | wdtmrctl = ioremap((unsigned long)(MMCR_BASE + OFFS_WDTMRCTL), 2); | |
396 | if (!wdtmrctl) { | |
397 | printk(KERN_ERR PFX "Unable to remap memory\n"); | |
398 | rc = -ENOMEM; | |
399 | goto err_out_region2; | |
400 | } | |
401 | ||
402 | rc = register_reboot_notifier(&wdt_notifier); | |
403 | if (rc) { | |
404 | printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", | |
405 | rc); | |
406 | goto err_out_ioremap; | |
407 | } | |
408 | ||
409 | rc = misc_register(&wdt_miscdev); | |
410 | if (rc) { | |
411 | printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", | |
412 | WATCHDOG_MINOR, rc); | |
413 | goto err_out_notifier; | |
414 | } | |
415 | ||
416 | printk(KERN_INFO PFX "WDT driver for SC520 initialised. timeout=%d sec (nowayout=%d)\n", | |
417 | timeout,nowayout); | |
418 | ||
419 | return 0; | |
420 | ||
421 | err_out_notifier: | |
422 | unregister_reboot_notifier(&wdt_notifier); | |
423 | err_out_ioremap: | |
424 | iounmap(wdtmrctl); | |
425 | err_out_region2: | |
426 | return rc; | |
427 | } | |
428 | ||
429 | module_init(sc520_wdt_init); | |
430 | module_exit(sc520_wdt_unload); | |
431 | ||
432 | MODULE_AUTHOR("Scott and Bill Jennings"); | |
433 | MODULE_DESCRIPTION("Driver for watchdog timer in AMD \"Elan\" SC520 uProcessor"); | |
434 | MODULE_LICENSE("GPL"); | |
435 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |