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30
31#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33#include <linux/module.h>
34#include <linux/moduleparam.h>
35#include <linux/types.h>
36#include <linux/timer.h>
37#include <linux/jiffies.h>
38#include <linux/miscdevice.h>
39#include <linux/watchdog.h>
40#include <linux/fs.h>
41#include <linux/ioport.h>
42#include <linux/notifier.h>
43#include <linux/reboot.h>
44#include <linux/init.h>
45#include <linux/io.h>
46#include <linux/uaccess.h>
47
48
49
50#define ZF_IOBASE 0x218
51#define INDEX 0x218
52#define DATA_B 0x219
53#define DATA_W 0x21A
54#define DATA_D 0x21A
55
56
57#define ZFL_VERSION 0x02
58#define CONTROL 0x10
59#define STATUS 0x12
60#define COUNTER_1 0x0C
61#define COUNTER_2 0x0E
62#define PULSE_LEN 0x0F
63
64
65#define ENABLE_WD1 0x0001
66#define ENABLE_WD2 0x0002
67#define RESET_WD1 0x0010
68#define RESET_WD2 0x0020
69#define GEN_SCI 0x0100
70#define GEN_NMI 0x0200
71#define GEN_SMI 0x0400
72#define GEN_RESET 0x0800
73
74
75
76
77#define WD1 0
78#define WD2 1
79
80#define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
81#define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
82#define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
83
84
85static unsigned short zf_readw(unsigned char port)
86{
87 outb(port, INDEX);
88 return inw(DATA_W);
89}
90
91
92MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
93MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
94MODULE_LICENSE("GPL");
95MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
96
97static bool nowayout = WATCHDOG_NOWAYOUT;
98module_param(nowayout, bool, 0);
99MODULE_PARM_DESC(nowayout,
100 "Watchdog cannot be stopped once started (default="
101 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
102
103#define PFX "machzwd"
104
105static const struct watchdog_info zf_info = {
106 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
107 .firmware_version = 1,
108 .identity = "ZF-Logic watchdog",
109};
110
111
112
113
114
115
116
117
118
119
120static int action;
121module_param(action, int, 0);
122MODULE_PARM_DESC(action, "after watchdog resets, generate: "
123 "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
124
125static void zf_ping(unsigned long data);
126
127static int zf_action = GEN_RESET;
128static unsigned long zf_is_open;
129static char zf_expect_close;
130static DEFINE_SPINLOCK(zf_port_lock);
131static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
132static unsigned long next_heartbeat;
133
134
135
136#define ZF_USER_TIMEO (HZ*10)
137
138
139#define ZF_HW_TIMEO (HZ/2)
140
141
142#define ZF_CTIMEOUT 0xffff
143
144#ifndef ZF_DEBUG
145#define dprintk(format, args...)
146#else
147#define dprintk(format, args...) \
148 pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
149#endif
150
151
152static inline void zf_set_status(unsigned char new)
153{
154 zf_writeb(STATUS, new);
155}
156
157
158
159
160static inline unsigned short zf_get_control(void)
161{
162 return zf_readw(CONTROL);
163}
164
165static inline void zf_set_control(unsigned short new)
166{
167 zf_writew(CONTROL, new);
168}
169
170
171
172
173
174
175
176static inline void zf_set_timer(unsigned short new, unsigned char n)
177{
178 switch (n) {
179 case WD1:
180 zf_writew(COUNTER_1, new);
181 case WD2:
182 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
183 default:
184 return;
185 }
186}
187
188
189
190
191static void zf_timer_off(void)
192{
193 unsigned int ctrl_reg = 0;
194 unsigned long flags;
195
196
197 del_timer_sync(&zf_timer);
198
199 spin_lock_irqsave(&zf_port_lock, flags);
200
201 ctrl_reg = zf_get_control();
202 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2);
203 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
204 zf_set_control(ctrl_reg);
205 spin_unlock_irqrestore(&zf_port_lock, flags);
206
207 pr_info("Watchdog timer is now disabled\n");
208}
209
210
211
212
213
214static void zf_timer_on(void)
215{
216 unsigned int ctrl_reg = 0;
217 unsigned long flags;
218
219 spin_lock_irqsave(&zf_port_lock, flags);
220
221 zf_writeb(PULSE_LEN, 0xff);
222
223 zf_set_timer(ZF_CTIMEOUT, WD1);
224
225
226 next_heartbeat = jiffies + ZF_USER_TIMEO;
227
228
229 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
230
231
232 ctrl_reg = zf_get_control();
233 ctrl_reg |= (ENABLE_WD1|zf_action);
234 zf_set_control(ctrl_reg);
235 spin_unlock_irqrestore(&zf_port_lock, flags);
236
237 pr_info("Watchdog timer is now enabled\n");
238}
239
240
241static void zf_ping(unsigned long data)
242{
243 unsigned int ctrl_reg = 0;
244 unsigned long flags;
245
246 zf_writeb(COUNTER_2, 0xff);
247
248 if (time_before(jiffies, next_heartbeat)) {
249 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
250
251
252
253
254
255 spin_lock_irqsave(&zf_port_lock, flags);
256 ctrl_reg = zf_get_control();
257 ctrl_reg |= RESET_WD1;
258 zf_set_control(ctrl_reg);
259
260
261 ctrl_reg &= ~(RESET_WD1);
262 zf_set_control(ctrl_reg);
263 spin_unlock_irqrestore(&zf_port_lock, flags);
264
265 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
266 } else
267 pr_crit("I will reset your machine\n");
268}
269
270static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
271 loff_t *ppos)
272{
273
274 if (count) {
275
276
277
278
279 if (!nowayout) {
280 size_t ofs;
281
282
283
284
285 zf_expect_close = 0;
286
287
288 for (ofs = 0; ofs != count; ofs++) {
289 char c;
290 if (get_user(c, buf + ofs))
291 return -EFAULT;
292 if (c == 'V') {
293 zf_expect_close = 42;
294 dprintk("zf_expect_close = 42\n");
295 }
296 }
297 }
298
299
300
301
302
303 next_heartbeat = jiffies + ZF_USER_TIMEO;
304 dprintk("user ping at %ld\n", jiffies);
305 }
306 return count;
307}
308
309static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
310{
311 void __user *argp = (void __user *)arg;
312 int __user *p = argp;
313 switch (cmd) {
314 case WDIOC_GETSUPPORT:
315 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
316 return -EFAULT;
317 break;
318 case WDIOC_GETSTATUS:
319 case WDIOC_GETBOOTSTATUS:
320 return put_user(0, p);
321 case WDIOC_KEEPALIVE:
322 zf_ping(0);
323 break;
324 default:
325 return -ENOTTY;
326 }
327 return 0;
328}
329
330static int zf_open(struct inode *inode, struct file *file)
331{
332 if (test_and_set_bit(0, &zf_is_open))
333 return -EBUSY;
334 if (nowayout)
335 __module_get(THIS_MODULE);
336 zf_timer_on();
337 return nonseekable_open(inode, file);
338}
339
340static int zf_close(struct inode *inode, struct file *file)
341{
342 if (zf_expect_close == 42)
343 zf_timer_off();
344 else {
345 del_timer(&zf_timer);
346 pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
347 }
348 clear_bit(0, &zf_is_open);
349 zf_expect_close = 0;
350 return 0;
351}
352
353
354
355
356
357static int zf_notify_sys(struct notifier_block *this, unsigned long code,
358 void *unused)
359{
360 if (code == SYS_DOWN || code == SYS_HALT)
361 zf_timer_off();
362 return NOTIFY_DONE;
363}
364
365static const struct file_operations zf_fops = {
366 .owner = THIS_MODULE,
367 .llseek = no_llseek,
368 .write = zf_write,
369 .unlocked_ioctl = zf_ioctl,
370 .open = zf_open,
371 .release = zf_close,
372};
373
374static struct miscdevice zf_miscdev = {
375 .minor = WATCHDOG_MINOR,
376 .name = "watchdog",
377 .fops = &zf_fops,
378};
379
380
381
382
383
384
385static struct notifier_block zf_notifier = {
386 .notifier_call = zf_notify_sys,
387};
388
389static void __init zf_show_action(int act)
390{
391 static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
392
393 pr_info("Watchdog using action = %s\n", str[act]);
394}
395
396static int __init zf_init(void)
397{
398 int ret;
399
400 pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
401
402 ret = zf_get_ZFL_version();
403 if (!ret || ret == 0xffff) {
404 pr_warn("no ZF-Logic found\n");
405 return -ENODEV;
406 }
407
408 if (action <= 3 && action >= 0)
409 zf_action = zf_action >> action;
410 else
411 action = 0;
412
413 zf_show_action(action);
414
415 if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
416 pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
417 ret = -EBUSY;
418 goto no_region;
419 }
420
421 ret = register_reboot_notifier(&zf_notifier);
422 if (ret) {
423 pr_err("can't register reboot notifier (err=%d)\n", ret);
424 goto no_reboot;
425 }
426
427 ret = misc_register(&zf_miscdev);
428 if (ret) {
429 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
430 goto no_misc;
431 }
432
433 zf_set_status(0);
434 zf_set_control(0);
435
436 return 0;
437
438no_misc:
439 unregister_reboot_notifier(&zf_notifier);
440no_reboot:
441 release_region(ZF_IOBASE, 3);
442no_region:
443 return ret;
444}
445
446
447static void __exit zf_exit(void)
448{
449 zf_timer_off();
450
451 misc_deregister(&zf_miscdev);
452 unregister_reboot_notifier(&zf_notifier);
453 release_region(ZF_IOBASE, 3);
454}
455
456module_init(zf_init);
457module_exit(zf_exit);
458