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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * MachZ ZF-Logic Watchdog Timer driver for Linux
4 *
5 * The author does NOT admit liability nor provide warranty for
6 * any of this software. This material is provided "AS-IS" in
7 * the hope that it may be useful for others.
8 *
9 * Author: Fernando Fuganti <fuganti@conectiva.com.br>
10 *
11 * Based on sbc60xxwdt.c by Jakob Oestergaard
12 *
13 * We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
14 * following periods:
15 * wd#1 - 2 seconds;
16 * wd#2 - 7.2 ms;
17 * After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
18 * a system RESET and it starts wd#2 that unconditionally will RESET
19 * the system when the counter reaches zero.
20 *
21 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
22 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
23 */
24
25#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26
27#include <linux/module.h>
28#include <linux/moduleparam.h>
29#include <linux/types.h>
30#include <linux/timer.h>
31#include <linux/jiffies.h>
32#include <linux/miscdevice.h>
33#include <linux/watchdog.h>
34#include <linux/fs.h>
35#include <linux/ioport.h>
36#include <linux/notifier.h>
37#include <linux/reboot.h>
38#include <linux/init.h>
39#include <linux/io.h>
40#include <linux/uaccess.h>
41
42
43/* ports */
44#define ZF_IOBASE 0x218
45#define INDEX 0x218
46#define DATA_B 0x219
47#define DATA_W 0x21A
48#define DATA_D 0x21A
49
50/* indexes */ /* size */
51#define ZFL_VERSION 0x02 /* 16 */
52#define CONTROL 0x10 /* 16 */
53#define STATUS 0x12 /* 8 */
54#define COUNTER_1 0x0C /* 16 */
55#define COUNTER_2 0x0E /* 8 */
56#define PULSE_LEN 0x0F /* 8 */
57
58/* controls */
59#define ENABLE_WD1 0x0001
60#define ENABLE_WD2 0x0002
61#define RESET_WD1 0x0010
62#define RESET_WD2 0x0020
63#define GEN_SCI 0x0100
64#define GEN_NMI 0x0200
65#define GEN_SMI 0x0400
66#define GEN_RESET 0x0800
67
68
69/* utilities */
70
71#define WD1 0
72#define WD2 1
73
74#define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
75#define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
76#define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
77
78
79static unsigned short zf_readw(unsigned char port)
80{
81 outb(port, INDEX);
82 return inw(DATA_W);
83}
84
85
86MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
87MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
88MODULE_LICENSE("GPL");
89
90static bool nowayout = WATCHDOG_NOWAYOUT;
91module_param(nowayout, bool, 0);
92MODULE_PARM_DESC(nowayout,
93 "Watchdog cannot be stopped once started (default="
94 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
95
96#define PFX "machzwd"
97
98static const struct watchdog_info zf_info = {
99 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
100 .firmware_version = 1,
101 .identity = "ZF-Logic watchdog",
102};
103
104
105/*
106 * action refers to action taken when watchdog resets
107 * 0 = GEN_RESET
108 * 1 = GEN_SMI
109 * 2 = GEN_NMI
110 * 3 = GEN_SCI
111 * defaults to GEN_RESET (0)
112 */
113static int action;
114module_param(action, int, 0);
115MODULE_PARM_DESC(action, "after watchdog resets, generate: "
116 "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
117
118static void zf_ping(struct timer_list *unused);
119
120static int zf_action = GEN_RESET;
121static unsigned long zf_is_open;
122static char zf_expect_close;
123static DEFINE_SPINLOCK(zf_port_lock);
124static DEFINE_TIMER(zf_timer, zf_ping);
125static unsigned long next_heartbeat;
126
127
128/* timeout for user land heart beat (10 seconds) */
129#define ZF_USER_TIMEO (HZ*10)
130
131/* timeout for hardware watchdog (~500ms) */
132#define ZF_HW_TIMEO (HZ/2)
133
134/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
135#define ZF_CTIMEOUT 0xffff
136
137#ifndef ZF_DEBUG
138#define dprintk(format, args...)
139#else
140#define dprintk(format, args...) \
141 pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
142#endif
143
144
145static inline void zf_set_status(unsigned char new)
146{
147 zf_writeb(STATUS, new);
148}
149
150
151/* CONTROL register functions */
152
153static inline unsigned short zf_get_control(void)
154{
155 return zf_readw(CONTROL);
156}
157
158static inline void zf_set_control(unsigned short new)
159{
160 zf_writew(CONTROL, new);
161}
162
163
164/* WD#? counter functions */
165/*
166 * Just set counter value
167 */
168
169static inline void zf_set_timer(unsigned short new, unsigned char n)
170{
171 switch (n) {
172 case WD1:
173 zf_writew(COUNTER_1, new);
174 fallthrough;
175 case WD2:
176 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
177 fallthrough;
178 default:
179 return;
180 }
181}
182
183/*
184 * stop hardware timer
185 */
186static void zf_timer_off(void)
187{
188 unsigned int ctrl_reg = 0;
189 unsigned long flags;
190
191 /* stop internal ping */
192 del_timer_sync(&zf_timer);
193
194 spin_lock_irqsave(&zf_port_lock, flags);
195 /* stop watchdog timer */
196 ctrl_reg = zf_get_control();
197 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
198 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
199 zf_set_control(ctrl_reg);
200 spin_unlock_irqrestore(&zf_port_lock, flags);
201
202 pr_info("Watchdog timer is now disabled\n");
203}
204
205
206/*
207 * start hardware timer
208 */
209static void zf_timer_on(void)
210{
211 unsigned int ctrl_reg = 0;
212 unsigned long flags;
213
214 spin_lock_irqsave(&zf_port_lock, flags);
215
216 zf_writeb(PULSE_LEN, 0xff);
217
218 zf_set_timer(ZF_CTIMEOUT, WD1);
219
220 /* user land ping */
221 next_heartbeat = jiffies + ZF_USER_TIMEO;
222
223 /* start the timer for internal ping */
224 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
225
226 /* start watchdog timer */
227 ctrl_reg = zf_get_control();
228 ctrl_reg |= (ENABLE_WD1|zf_action);
229 zf_set_control(ctrl_reg);
230 spin_unlock_irqrestore(&zf_port_lock, flags);
231
232 pr_info("Watchdog timer is now enabled\n");
233}
234
235
236static void zf_ping(struct timer_list *unused)
237{
238 unsigned int ctrl_reg = 0;
239 unsigned long flags;
240
241 zf_writeb(COUNTER_2, 0xff);
242
243 if (time_before(jiffies, next_heartbeat)) {
244 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
245 /*
246 * reset event is activated by transition from 0 to 1 on
247 * RESET_WD1 bit and we assume that it is already zero...
248 */
249
250 spin_lock_irqsave(&zf_port_lock, flags);
251 ctrl_reg = zf_get_control();
252 ctrl_reg |= RESET_WD1;
253 zf_set_control(ctrl_reg);
254
255 /* ...and nothing changes until here */
256 ctrl_reg &= ~(RESET_WD1);
257 zf_set_control(ctrl_reg);
258 spin_unlock_irqrestore(&zf_port_lock, flags);
259
260 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
261 } else
262 pr_crit("I will reset your machine\n");
263}
264
265static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
266 loff_t *ppos)
267{
268 /* See if we got the magic character */
269 if (count) {
270 /*
271 * no need to check for close confirmation
272 * no way to disable watchdog ;)
273 */
274 if (!nowayout) {
275 size_t ofs;
276 /*
277 * note: just in case someone wrote the magic character
278 * five months ago...
279 */
280 zf_expect_close = 0;
281
282 /* now scan */
283 for (ofs = 0; ofs != count; ofs++) {
284 char c;
285 if (get_user(c, buf + ofs))
286 return -EFAULT;
287 if (c == 'V') {
288 zf_expect_close = 42;
289 dprintk("zf_expect_close = 42\n");
290 }
291 }
292 }
293
294 /*
295 * Well, anyhow someone wrote to us,
296 * we should return that favour
297 */
298 next_heartbeat = jiffies + ZF_USER_TIMEO;
299 dprintk("user ping at %ld\n", jiffies);
300 }
301 return count;
302}
303
304static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
305{
306 void __user *argp = (void __user *)arg;
307 int __user *p = argp;
308 switch (cmd) {
309 case WDIOC_GETSUPPORT:
310 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
311 return -EFAULT;
312 break;
313 case WDIOC_GETSTATUS:
314 case WDIOC_GETBOOTSTATUS:
315 return put_user(0, p);
316 case WDIOC_KEEPALIVE:
317 zf_ping(NULL);
318 break;
319 default:
320 return -ENOTTY;
321 }
322 return 0;
323}
324
325static int zf_open(struct inode *inode, struct file *file)
326{
327 if (test_and_set_bit(0, &zf_is_open))
328 return -EBUSY;
329 if (nowayout)
330 __module_get(THIS_MODULE);
331 zf_timer_on();
332 return stream_open(inode, file);
333}
334
335static int zf_close(struct inode *inode, struct file *file)
336{
337 if (zf_expect_close == 42)
338 zf_timer_off();
339 else {
340 del_timer(&zf_timer);
341 pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
342 }
343 clear_bit(0, &zf_is_open);
344 zf_expect_close = 0;
345 return 0;
346}
347
348/*
349 * Notifier for system down
350 */
351
352static int zf_notify_sys(struct notifier_block *this, unsigned long code,
353 void *unused)
354{
355 if (code == SYS_DOWN || code == SYS_HALT)
356 zf_timer_off();
357 return NOTIFY_DONE;
358}
359
360static const struct file_operations zf_fops = {
361 .owner = THIS_MODULE,
362 .llseek = no_llseek,
363 .write = zf_write,
364 .unlocked_ioctl = zf_ioctl,
365 .compat_ioctl = compat_ptr_ioctl,
366 .open = zf_open,
367 .release = zf_close,
368};
369
370static struct miscdevice zf_miscdev = {
371 .minor = WATCHDOG_MINOR,
372 .name = "watchdog",
373 .fops = &zf_fops,
374};
375
376
377/*
378 * The device needs to learn about soft shutdowns in order to
379 * turn the timebomb registers off.
380 */
381static struct notifier_block zf_notifier = {
382 .notifier_call = zf_notify_sys,
383};
384
385static void __init zf_show_action(int act)
386{
387 static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
388
389 pr_info("Watchdog using action = %s\n", str[act]);
390}
391
392static int __init zf_init(void)
393{
394 int ret;
395
396 pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
397
398 ret = zf_get_ZFL_version();
399 if (!ret || ret == 0xffff) {
400 pr_warn("no ZF-Logic found\n");
401 return -ENODEV;
402 }
403
404 if (action <= 3 && action >= 0)
405 zf_action = zf_action >> action;
406 else
407 action = 0;
408
409 zf_show_action(action);
410
411 if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
412 pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
413 ret = -EBUSY;
414 goto no_region;
415 }
416
417 ret = register_reboot_notifier(&zf_notifier);
418 if (ret) {
419 pr_err("can't register reboot notifier (err=%d)\n", ret);
420 goto no_reboot;
421 }
422
423 ret = misc_register(&zf_miscdev);
424 if (ret) {
425 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
426 goto no_misc;
427 }
428
429 zf_set_status(0);
430 zf_set_control(0);
431
432 return 0;
433
434no_misc:
435 unregister_reboot_notifier(&zf_notifier);
436no_reboot:
437 release_region(ZF_IOBASE, 3);
438no_region:
439 return ret;
440}
441
442
443static void __exit zf_exit(void)
444{
445 zf_timer_off();
446
447 misc_deregister(&zf_miscdev);
448 unregister_reboot_notifier(&zf_notifier);
449 release_region(ZF_IOBASE, 3);
450}
451
452module_init(zf_init);
453module_exit(zf_exit);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * MachZ ZF-Logic Watchdog Timer driver for Linux
4 *
5 * The author does NOT admit liability nor provide warranty for
6 * any of this software. This material is provided "AS-IS" in
7 * the hope that it may be useful for others.
8 *
9 * Author: Fernando Fuganti <fuganti@conectiva.com.br>
10 *
11 * Based on sbc60xxwdt.c by Jakob Oestergaard
12 *
13 * We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
14 * following periods:
15 * wd#1 - 2 seconds;
16 * wd#2 - 7.2 ms;
17 * After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
18 * a system RESET and it starts wd#2 that unconditionally will RESET
19 * the system when the counter reaches zero.
20 *
21 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
22 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
23 */
24
25#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26
27#include <linux/module.h>
28#include <linux/moduleparam.h>
29#include <linux/types.h>
30#include <linux/timer.h>
31#include <linux/jiffies.h>
32#include <linux/miscdevice.h>
33#include <linux/watchdog.h>
34#include <linux/fs.h>
35#include <linux/ioport.h>
36#include <linux/notifier.h>
37#include <linux/reboot.h>
38#include <linux/init.h>
39#include <linux/io.h>
40#include <linux/uaccess.h>
41
42
43/* ports */
44#define ZF_IOBASE 0x218
45#define INDEX 0x218
46#define DATA_B 0x219
47#define DATA_W 0x21A
48#define DATA_D 0x21A
49
50/* indexes */ /* size */
51#define ZFL_VERSION 0x02 /* 16 */
52#define CONTROL 0x10 /* 16 */
53#define STATUS 0x12 /* 8 */
54#define COUNTER_1 0x0C /* 16 */
55#define COUNTER_2 0x0E /* 8 */
56#define PULSE_LEN 0x0F /* 8 */
57
58/* controls */
59#define ENABLE_WD1 0x0001
60#define ENABLE_WD2 0x0002
61#define RESET_WD1 0x0010
62#define RESET_WD2 0x0020
63#define GEN_SCI 0x0100
64#define GEN_NMI 0x0200
65#define GEN_SMI 0x0400
66#define GEN_RESET 0x0800
67
68
69/* utilities */
70
71#define WD1 0
72#define WD2 1
73
74#define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
75#define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
76#define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
77
78
79static unsigned short zf_readw(unsigned char port)
80{
81 outb(port, INDEX);
82 return inw(DATA_W);
83}
84
85
86MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
87MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
88MODULE_LICENSE("GPL");
89
90static bool nowayout = WATCHDOG_NOWAYOUT;
91module_param(nowayout, bool, 0);
92MODULE_PARM_DESC(nowayout,
93 "Watchdog cannot be stopped once started (default="
94 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
95
96#define PFX "machzwd"
97
98static const struct watchdog_info zf_info = {
99 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
100 .firmware_version = 1,
101 .identity = "ZF-Logic watchdog",
102};
103
104
105/*
106 * action refers to action taken when watchdog resets
107 * 0 = GEN_RESET
108 * 1 = GEN_SMI
109 * 2 = GEN_NMI
110 * 3 = GEN_SCI
111 * defaults to GEN_RESET (0)
112 */
113static int action;
114module_param(action, int, 0);
115MODULE_PARM_DESC(action, "after watchdog resets, generate: "
116 "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
117
118static void zf_ping(struct timer_list *unused);
119
120static int zf_action = GEN_RESET;
121static unsigned long zf_is_open;
122static char zf_expect_close;
123static DEFINE_SPINLOCK(zf_port_lock);
124static DEFINE_TIMER(zf_timer, zf_ping);
125static unsigned long next_heartbeat;
126
127
128/* timeout for user land heart beat (10 seconds) */
129#define ZF_USER_TIMEO (HZ*10)
130
131/* timeout for hardware watchdog (~500ms) */
132#define ZF_HW_TIMEO (HZ/2)
133
134/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
135#define ZF_CTIMEOUT 0xffff
136
137#ifndef ZF_DEBUG
138#define dprintk(format, args...)
139#else
140#define dprintk(format, args...) \
141 pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
142#endif
143
144
145static inline void zf_set_status(unsigned char new)
146{
147 zf_writeb(STATUS, new);
148}
149
150
151/* CONTROL register functions */
152
153static inline unsigned short zf_get_control(void)
154{
155 return zf_readw(CONTROL);
156}
157
158static inline void zf_set_control(unsigned short new)
159{
160 zf_writew(CONTROL, new);
161}
162
163
164/* WD#? counter functions */
165/*
166 * Just set counter value
167 */
168
169static inline void zf_set_timer(unsigned short new, unsigned char n)
170{
171 switch (n) {
172 case WD1:
173 zf_writew(COUNTER_1, new);
174 fallthrough;
175 case WD2:
176 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
177 default:
178 return;
179 }
180}
181
182/*
183 * stop hardware timer
184 */
185static void zf_timer_off(void)
186{
187 unsigned int ctrl_reg = 0;
188 unsigned long flags;
189
190 /* stop internal ping */
191 del_timer_sync(&zf_timer);
192
193 spin_lock_irqsave(&zf_port_lock, flags);
194 /* stop watchdog timer */
195 ctrl_reg = zf_get_control();
196 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
197 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
198 zf_set_control(ctrl_reg);
199 spin_unlock_irqrestore(&zf_port_lock, flags);
200
201 pr_info("Watchdog timer is now disabled\n");
202}
203
204
205/*
206 * start hardware timer
207 */
208static void zf_timer_on(void)
209{
210 unsigned int ctrl_reg = 0;
211 unsigned long flags;
212
213 spin_lock_irqsave(&zf_port_lock, flags);
214
215 zf_writeb(PULSE_LEN, 0xff);
216
217 zf_set_timer(ZF_CTIMEOUT, WD1);
218
219 /* user land ping */
220 next_heartbeat = jiffies + ZF_USER_TIMEO;
221
222 /* start the timer for internal ping */
223 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
224
225 /* start watchdog timer */
226 ctrl_reg = zf_get_control();
227 ctrl_reg |= (ENABLE_WD1|zf_action);
228 zf_set_control(ctrl_reg);
229 spin_unlock_irqrestore(&zf_port_lock, flags);
230
231 pr_info("Watchdog timer is now enabled\n");
232}
233
234
235static void zf_ping(struct timer_list *unused)
236{
237 unsigned int ctrl_reg = 0;
238 unsigned long flags;
239
240 zf_writeb(COUNTER_2, 0xff);
241
242 if (time_before(jiffies, next_heartbeat)) {
243 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
244 /*
245 * reset event is activated by transition from 0 to 1 on
246 * RESET_WD1 bit and we assume that it is already zero...
247 */
248
249 spin_lock_irqsave(&zf_port_lock, flags);
250 ctrl_reg = zf_get_control();
251 ctrl_reg |= RESET_WD1;
252 zf_set_control(ctrl_reg);
253
254 /* ...and nothing changes until here */
255 ctrl_reg &= ~(RESET_WD1);
256 zf_set_control(ctrl_reg);
257 spin_unlock_irqrestore(&zf_port_lock, flags);
258
259 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
260 } else
261 pr_crit("I will reset your machine\n");
262}
263
264static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
265 loff_t *ppos)
266{
267 /* See if we got the magic character */
268 if (count) {
269 /*
270 * no need to check for close confirmation
271 * no way to disable watchdog ;)
272 */
273 if (!nowayout) {
274 size_t ofs;
275 /*
276 * note: just in case someone wrote the magic character
277 * five months ago...
278 */
279 zf_expect_close = 0;
280
281 /* now scan */
282 for (ofs = 0; ofs != count; ofs++) {
283 char c;
284 if (get_user(c, buf + ofs))
285 return -EFAULT;
286 if (c == 'V') {
287 zf_expect_close = 42;
288 dprintk("zf_expect_close = 42\n");
289 }
290 }
291 }
292
293 /*
294 * Well, anyhow someone wrote to us,
295 * we should return that favour
296 */
297 next_heartbeat = jiffies + ZF_USER_TIMEO;
298 dprintk("user ping at %ld\n", jiffies);
299 }
300 return count;
301}
302
303static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
304{
305 void __user *argp = (void __user *)arg;
306 int __user *p = argp;
307 switch (cmd) {
308 case WDIOC_GETSUPPORT:
309 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
310 return -EFAULT;
311 break;
312 case WDIOC_GETSTATUS:
313 case WDIOC_GETBOOTSTATUS:
314 return put_user(0, p);
315 case WDIOC_KEEPALIVE:
316 zf_ping(NULL);
317 break;
318 default:
319 return -ENOTTY;
320 }
321 return 0;
322}
323
324static int zf_open(struct inode *inode, struct file *file)
325{
326 if (test_and_set_bit(0, &zf_is_open))
327 return -EBUSY;
328 if (nowayout)
329 __module_get(THIS_MODULE);
330 zf_timer_on();
331 return stream_open(inode, file);
332}
333
334static int zf_close(struct inode *inode, struct file *file)
335{
336 if (zf_expect_close == 42)
337 zf_timer_off();
338 else {
339 del_timer(&zf_timer);
340 pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
341 }
342 clear_bit(0, &zf_is_open);
343 zf_expect_close = 0;
344 return 0;
345}
346
347/*
348 * Notifier for system down
349 */
350
351static int zf_notify_sys(struct notifier_block *this, unsigned long code,
352 void *unused)
353{
354 if (code == SYS_DOWN || code == SYS_HALT)
355 zf_timer_off();
356 return NOTIFY_DONE;
357}
358
359static const struct file_operations zf_fops = {
360 .owner = THIS_MODULE,
361 .llseek = no_llseek,
362 .write = zf_write,
363 .unlocked_ioctl = zf_ioctl,
364 .compat_ioctl = compat_ptr_ioctl,
365 .open = zf_open,
366 .release = zf_close,
367};
368
369static struct miscdevice zf_miscdev = {
370 .minor = WATCHDOG_MINOR,
371 .name = "watchdog",
372 .fops = &zf_fops,
373};
374
375
376/*
377 * The device needs to learn about soft shutdowns in order to
378 * turn the timebomb registers off.
379 */
380static struct notifier_block zf_notifier = {
381 .notifier_call = zf_notify_sys,
382};
383
384static void __init zf_show_action(int act)
385{
386 static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
387
388 pr_info("Watchdog using action = %s\n", str[act]);
389}
390
391static int __init zf_init(void)
392{
393 int ret;
394
395 pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
396
397 ret = zf_get_ZFL_version();
398 if (!ret || ret == 0xffff) {
399 pr_warn("no ZF-Logic found\n");
400 return -ENODEV;
401 }
402
403 if (action <= 3 && action >= 0)
404 zf_action = zf_action >> action;
405 else
406 action = 0;
407
408 zf_show_action(action);
409
410 if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
411 pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
412 ret = -EBUSY;
413 goto no_region;
414 }
415
416 ret = register_reboot_notifier(&zf_notifier);
417 if (ret) {
418 pr_err("can't register reboot notifier (err=%d)\n", ret);
419 goto no_reboot;
420 }
421
422 ret = misc_register(&zf_miscdev);
423 if (ret) {
424 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
425 goto no_misc;
426 }
427
428 zf_set_status(0);
429 zf_set_control(0);
430
431 return 0;
432
433no_misc:
434 unregister_reboot_notifier(&zf_notifier);
435no_reboot:
436 release_region(ZF_IOBASE, 3);
437no_region:
438 return ret;
439}
440
441
442static void __exit zf_exit(void)
443{
444 zf_timer_off();
445
446 misc_deregister(&zf_miscdev);
447 unregister_reboot_notifier(&zf_notifier);
448 release_region(ZF_IOBASE, 3);
449}
450
451module_init(zf_init);
452module_exit(zf_exit);