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22
23#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24
25#include <linux/module.h>
26#include <linux/moduleparam.h>
27#include <linux/types.h>
28#include <linux/timer.h>
29#include <linux/miscdevice.h>
30#include <linux/watchdog.h>
31#include <linux/ioport.h>
32#include <linux/notifier.h>
33#include <linux/reboot.h>
34#include <linux/init.h>
35#include <linux/fs.h>
36#include <linux/pci.h>
37#include <linux/io.h>
38#include <linux/uaccess.h>
39
40
41#define WDT_ENABLE 0x9C
42#define WDT_DISABLE 0x8C
43
44#define ALI_7101_WDT 0x92
45#define ALI_7101_GPIO 0x7D
46#define ALI_7101_GPIO_O 0x7E
47#define ALI_WDT_ARM 0x01
48
49
50
51
52
53#define WDT_INTERVAL (HZ/4+1)
54
55
56
57
58
59
60
61#define WATCHDOG_TIMEOUT 30
62
63static int timeout = WATCHDOG_TIMEOUT;
64module_param(timeout, int, 0);
65MODULE_PARM_DESC(timeout,
66 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
67 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
68
69static int use_gpio;
70module_param(use_gpio, int, 0);
71MODULE_PARM_DESC(use_gpio,
72 "Use the gpio watchdog (required by old cobalt boards).");
73
74static void wdt_timer_ping(struct timer_list *);
75static DEFINE_TIMER(timer, wdt_timer_ping);
76static unsigned long next_heartbeat;
77static unsigned long wdt_is_open;
78static char wdt_expect_close;
79static struct pci_dev *alim7101_pmu;
80
81static bool nowayout = WATCHDOG_NOWAYOUT;
82module_param(nowayout, bool, 0);
83MODULE_PARM_DESC(nowayout,
84 "Watchdog cannot be stopped once started (default="
85 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
86
87
88
89
90
91static void wdt_timer_ping(struct timer_list *unused)
92{
93
94
95
96 char tmp;
97
98 if (time_before(jiffies, next_heartbeat)) {
99
100 pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
101 pci_write_config_byte(alim7101_pmu,
102 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
103 pci_write_config_byte(alim7101_pmu,
104 ALI_7101_WDT, (tmp | ALI_WDT_ARM));
105 if (use_gpio) {
106 pci_read_config_byte(alim7101_pmu,
107 ALI_7101_GPIO_O, &tmp);
108 pci_write_config_byte(alim7101_pmu,
109 ALI_7101_GPIO_O, tmp | 0x20);
110 pci_write_config_byte(alim7101_pmu,
111 ALI_7101_GPIO_O, tmp & ~0x20);
112 }
113 } else {
114 pr_warn("Heartbeat lost! Will not ping the watchdog\n");
115 }
116
117 mod_timer(&timer, jiffies + WDT_INTERVAL);
118}
119
120
121
122
123
124static void wdt_change(int writeval)
125{
126 char tmp;
127
128 pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
129 if (writeval == WDT_ENABLE) {
130 pci_write_config_byte(alim7101_pmu,
131 ALI_7101_WDT, (tmp | ALI_WDT_ARM));
132 if (use_gpio) {
133 pci_read_config_byte(alim7101_pmu,
134 ALI_7101_GPIO_O, &tmp);
135 pci_write_config_byte(alim7101_pmu,
136 ALI_7101_GPIO_O, tmp & ~0x20);
137 }
138
139 } else {
140 pci_write_config_byte(alim7101_pmu,
141 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
142 if (use_gpio) {
143 pci_read_config_byte(alim7101_pmu,
144 ALI_7101_GPIO_O, &tmp);
145 pci_write_config_byte(alim7101_pmu,
146 ALI_7101_GPIO_O, tmp | 0x20);
147 }
148 }
149}
150
151static void wdt_startup(void)
152{
153 next_heartbeat = jiffies + (timeout * HZ);
154
155
156
157
158 wdt_change(WDT_ENABLE);
159
160
161 mod_timer(&timer, jiffies + WDT_INTERVAL);
162
163 pr_info("Watchdog timer is now enabled\n");
164}
165
166static void wdt_turnoff(void)
167{
168
169 del_timer_sync(&timer);
170 wdt_change(WDT_DISABLE);
171 pr_info("Watchdog timer is now disabled...\n");
172}
173
174static void wdt_keepalive(void)
175{
176
177 next_heartbeat = jiffies + (timeout * HZ);
178}
179
180
181
182
183
184static ssize_t fop_write(struct file *file, const char __user *buf,
185 size_t count, loff_t *ppos)
186{
187
188 if (count) {
189 if (!nowayout) {
190 size_t ofs;
191
192
193
194 wdt_expect_close = 0;
195
196
197 for (ofs = 0; ofs != count; ofs++) {
198 char c;
199 if (get_user(c, buf + ofs))
200 return -EFAULT;
201 if (c == 'V')
202 wdt_expect_close = 42;
203 }
204 }
205
206 wdt_keepalive();
207 }
208 return count;
209}
210
211static int fop_open(struct inode *inode, struct file *file)
212{
213
214 if (test_and_set_bit(0, &wdt_is_open))
215 return -EBUSY;
216
217 wdt_startup();
218 return stream_open(inode, file);
219}
220
221static int fop_close(struct inode *inode, struct file *file)
222{
223 if (wdt_expect_close == 42)
224 wdt_turnoff();
225 else {
226
227 pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
228 }
229 clear_bit(0, &wdt_is_open);
230 wdt_expect_close = 0;
231 return 0;
232}
233
234static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
235{
236 void __user *argp = (void __user *)arg;
237 int __user *p = argp;
238 static const struct watchdog_info ident = {
239 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
240 | WDIOF_MAGICCLOSE,
241 .firmware_version = 1,
242 .identity = "ALiM7101",
243 };
244
245 switch (cmd) {
246 case WDIOC_GETSUPPORT:
247 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
248 case WDIOC_GETSTATUS:
249 case WDIOC_GETBOOTSTATUS:
250 return put_user(0, p);
251 case WDIOC_SETOPTIONS:
252 {
253 int new_options, retval = -EINVAL;
254
255 if (get_user(new_options, p))
256 return -EFAULT;
257 if (new_options & WDIOS_DISABLECARD) {
258 wdt_turnoff();
259 retval = 0;
260 }
261 if (new_options & WDIOS_ENABLECARD) {
262 wdt_startup();
263 retval = 0;
264 }
265 return retval;
266 }
267 case WDIOC_KEEPALIVE:
268 wdt_keepalive();
269 return 0;
270 case WDIOC_SETTIMEOUT:
271 {
272 int new_timeout;
273
274 if (get_user(new_timeout, p))
275 return -EFAULT;
276
277 if (new_timeout < 1 || new_timeout > 3600)
278 return -EINVAL;
279 timeout = new_timeout;
280 wdt_keepalive();
281 }
282 fallthrough;
283 case WDIOC_GETTIMEOUT:
284 return put_user(timeout, p);
285 default:
286 return -ENOTTY;
287 }
288}
289
290static const struct file_operations wdt_fops = {
291 .owner = THIS_MODULE,
292 .llseek = no_llseek,
293 .write = fop_write,
294 .open = fop_open,
295 .release = fop_close,
296 .unlocked_ioctl = fop_ioctl,
297 .compat_ioctl = compat_ptr_ioctl,
298};
299
300static struct miscdevice wdt_miscdev = {
301 .minor = WATCHDOG_MINOR,
302 .name = "watchdog",
303 .fops = &wdt_fops,
304};
305
306static int wdt_restart_handle(struct notifier_block *this, unsigned long mode,
307 void *cmd)
308{
309
310
311
312
313
314 wdt_change(WDT_ENABLE);
315
316
317 while (true)
318 ;
319
320 return NOTIFY_DONE;
321}
322
323static struct notifier_block wdt_restart_handler = {
324 .notifier_call = wdt_restart_handle,
325 .priority = 128,
326};
327
328
329
330
331
332static int wdt_notify_sys(struct notifier_block *this,
333 unsigned long code, void *unused)
334{
335 if (code == SYS_DOWN || code == SYS_HALT)
336 wdt_turnoff();
337
338 return NOTIFY_DONE;
339}
340
341
342
343
344
345
346static struct notifier_block wdt_notifier = {
347 .notifier_call = wdt_notify_sys,
348};
349
350static void __exit alim7101_wdt_unload(void)
351{
352 wdt_turnoff();
353
354 misc_deregister(&wdt_miscdev);
355 unregister_reboot_notifier(&wdt_notifier);
356 unregister_restart_handler(&wdt_restart_handler);
357 pci_dev_put(alim7101_pmu);
358}
359
360static int __init alim7101_wdt_init(void)
361{
362 int rc = -EBUSY;
363 struct pci_dev *ali1543_south;
364 char tmp;
365
366 pr_info("Steve Hill <steve@navaho.co.uk>\n");
367 alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
368 NULL);
369 if (!alim7101_pmu) {
370 pr_info("ALi M7101 PMU not present - WDT not set\n");
371 return -EBUSY;
372 }
373
374
375 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
376
377 ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
378 NULL);
379 if (!ali1543_south) {
380 pr_info("ALi 1543 South-Bridge not present - WDT not set\n");
381 goto err_out;
382 }
383 pci_read_config_byte(ali1543_south, 0x5e, &tmp);
384 pci_dev_put(ali1543_south);
385 if ((tmp & 0x1e) == 0x00) {
386 if (!use_gpio) {
387 pr_info("Detected old alim7101 revision 'a1d'. If this is a cobalt board, set the 'use_gpio' module parameter.\n");
388 goto err_out;
389 }
390 nowayout = 1;
391 } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
392 pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
393 goto err_out;
394 }
395
396 if (timeout < 1 || timeout > 3600) {
397
398 timeout = WATCHDOG_TIMEOUT;
399 pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
400 timeout);
401 }
402
403 rc = register_reboot_notifier(&wdt_notifier);
404 if (rc) {
405 pr_err("cannot register reboot notifier (err=%d)\n", rc);
406 goto err_out;
407 }
408
409 rc = register_restart_handler(&wdt_restart_handler);
410 if (rc) {
411 pr_err("cannot register restart handler (err=%d)\n", rc);
412 goto err_out_reboot;
413 }
414
415 rc = misc_register(&wdt_miscdev);
416 if (rc) {
417 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
418 wdt_miscdev.minor, rc);
419 goto err_out_restart;
420 }
421
422 if (nowayout)
423 __module_get(THIS_MODULE);
424
425 pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
426 timeout, nowayout);
427 return 0;
428
429err_out_restart:
430 unregister_restart_handler(&wdt_restart_handler);
431err_out_reboot:
432 unregister_reboot_notifier(&wdt_notifier);
433err_out:
434 pci_dev_put(alim7101_pmu);
435 return rc;
436}
437
438module_init(alim7101_wdt_init);
439module_exit(alim7101_wdt_unload);
440
441static const struct pci_device_id alim7101_pci_tbl[] __used = {
442 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
443 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
444 { }
445};
446
447MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
448
449MODULE_AUTHOR("Steve Hill");
450MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
451MODULE_LICENSE("GPL");
452
