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authorWim Van Sebroeck <wim@iguana.be>2007-08-17 04:38:02 -0400
committerWim Van Sebroeck <wim@iguana.be>2007-10-18 06:39:03 -0400
commitb7e04f8c61a46d742de23af5d7ca2b41b33e40ac (patch)
treec52a7ea568648e2d8ed0d423098b42298de2058b /drivers/watchdog/sc520_wdt.c
parentd85714d81cc0408daddb68c10f7fd69eafe7c213 (diff)
mv watchdog tree under drivers
move watchdog tree from drivers/char/watchdog to drivers/watchdog. Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'drivers/watchdog/sc520_wdt.c')
-rw-r--r--drivers/watchdog/sc520_wdt.c435
1 files changed, 435 insertions, 0 deletions
diff --git a/drivers/watchdog/sc520_wdt.c b/drivers/watchdog/sc520_wdt.c
new file mode 100644
index 000000000000..e8594c64d1e6
--- /dev/null
+++ b/drivers/watchdog/sc520_wdt.c
@@ -0,0 +1,435 @@
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>
66#include <linux/jiffies.h>
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 */
94static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
95module_param(timeout, int, 0);
96MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
97
98static int nowayout = WATCHDOG_NOWAYOUT;
99module_param(nowayout, int, 0);
100MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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
121static __u16 __iomem *wdtmrctl;
122
123static void wdt_timer_ping(unsigned long);
124static DEFINE_TIMER(timer, wdt_timer_ping, 0, 0);
125static unsigned long next_heartbeat;
126static unsigned long wdt_is_open;
127static char wdt_expect_close;
128static spinlock_t wdt_spinlock;
129
130/*
131 * Whack the dog
132 */
133
134static 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 */
148 mod_timer(&timer, jiffies + WDT_INTERVAL);
149 } else {
150 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
151 }
152}
153
154/*
155 * Utility routines
156 */
157
158static 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
176static int wdt_startup(void)
177{
178 next_heartbeat = jiffies + (timeout * HZ);
179
180 /* Start the timer */
181 mod_timer(&timer, jiffies + WDT_INTERVAL);
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
190static 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
202static int wdt_keepalive(void)
203{
204 /* user land ping */
205 next_heartbeat = jiffies + (timeout * HZ);
206 return 0;
207}
208
209static 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
222static 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
249static int fop_open(struct inode * inode, struct file * file)
250{
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();
259 return nonseekable_open(inode, file);
260}
261
262static 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
275static 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:
289 return -ENOTTY;
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
335static const struct file_operations wdt_fops = {
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
344static 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
354static 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
367static struct notifier_block wdt_notifier = {
368 .notifier_call = wdt_notify_sys,
369};
370
371static 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
382static int __init sc520_wdt_init(void)
383{
384 int rc = -EBUSY;
385
386 spin_lock_init(&wdt_spinlock);
387
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
421err_out_notifier:
422 unregister_reboot_notifier(&wdt_notifier);
423err_out_ioremap:
424 iounmap(wdtmrctl);
425err_out_region2:
426 return rc;
427}
428
429module_init(sc520_wdt_init);
430module_exit(sc520_wdt_unload);
431
432MODULE_AUTHOR("Scott and Bill Jennings");
433MODULE_DESCRIPTION("Driver for watchdog timer in AMD \"Elan\" SC520 uProcessor");
434MODULE_LICENSE("GPL");
435MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);