1/*
2 *	ALi M7101 PMU Computer Watchdog Timer driver
3 *
4 *	Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net>
5 *	and the Cobalt kernel WDT timer driver by Tim Hockin
6 *	                                      <thockin@cobaltnet.com>
7 *
8 *	(c)2002 Steve Hill <steve@navaho.co.uk>
9 *
10 *  This WDT driver is different from most other Linux WDT
11 *  drivers in that the driver will ping the watchdog by itself,
12 *  because this particular WDT has a very short timeout (1.6
13 *  seconds) and it would be insane to count on any userspace
14 *  daemon always getting scheduled within that time frame.
15 *
16 *  Additions:
17 *   Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs
18 *                  found on very old cobalt hardware.
19 *                  -- Mike Waychison <michael.waychison@sun.com>
20 */
21
22#include <linux/module.h>
23#include <linux/moduleparam.h>
24#include <linux/types.h>
25#include <linux/timer.h>
26#include <linux/miscdevice.h>
27#include <linux/watchdog.h>
28#include <linux/ioport.h>
29#include <linux/notifier.h>
30#include <linux/reboot.h>
31#include <linux/init.h>
32#include <linux/fs.h>
33#include <linux/pci.h>
34
35#include <asm/io.h>
36#include <asm/uaccess.h>
37#include <asm/system.h>
38
39#define OUR_NAME "alim7101_wdt"
40#define PFX OUR_NAME ": "
41
42#define WDT_ENABLE 0x9C
43#define WDT_DISABLE 0x8C
44
45#define ALI_7101_WDT    0x92
46#define ALI_7101_GPIO   0x7D
47#define ALI_7101_GPIO_O 0x7E
48#define ALI_WDT_ARM     0x01
49
50/*
51 * We're going to use a 1 second timeout.
52 * If we reset the watchdog every ~250ms we should be safe.  */
53
54#define WDT_INTERVAL (HZ/4+1)
55
56/*
57 * We must not require too good response from the userspace daemon.
58 * Here we require the userspace daemon to send us a heartbeat
59 * char to /dev/watchdog every 30 seconds.
60 */
61
62#define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */
63static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
64module_param(timeout, int, 0);
65MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
66
67static int use_gpio = 0; /* Use the pic (for a1d revision alim7101) */
68module_param(use_gpio, int, 0);
69MODULE_PARM_DESC(use_gpio, "Use the gpio watchdog.  (required by old cobalt boards)");
70
71static void wdt_timer_ping(unsigned long);
72static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
73static unsigned long next_heartbeat;
74static unsigned long wdt_is_open;
75static char wdt_expect_close;
76static struct pci_dev *alim7101_pmu;
77
78static int nowayout = WATCHDOG_NOWAYOUT;
79module_param(nowayout, int, 0);
80MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
81		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
82
83/*
84 *	Whack the dog
85 */
86
87static void wdt_timer_ping(unsigned long data)
88{
89	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
90	 * we agree to ping the WDT
91	 */
92	char	tmp;
93
94	if(time_before(jiffies, next_heartbeat))
95	{
96		/* Ping the WDT (this is actually a disarm/arm sequence) */
97		pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
98		pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
99		pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
100		if (use_gpio) {
101			pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
102			pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp
103					| 0x20);
104			pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp
105					& ~0x20);
106		}
107	} else {
108		printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
109	}
110	/* Re-set the timer interval */
111	mod_timer(&timer, jiffies + WDT_INTERVAL);
112}
113
114/*
115 * Utility routines
116 */
117
118static void wdt_change(int writeval)
119{
120	char	tmp;
121
122	pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
123	if (writeval == WDT_ENABLE) {
124		pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
125		if (use_gpio) {
126			pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
127			pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp & ~0x20);
128		}
129
130	} else {
131		pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
132		if (use_gpio) {
133			pci_read_config_byte(alim7101_pmu, ALI_7101_GPIO_O, &tmp);
134			pci_write_config_byte(alim7101_pmu, ALI_7101_GPIO_O, tmp | 0x20);
135		}
136	}
137}
138
139static void wdt_startup(void)
140{
141	next_heartbeat = jiffies + (timeout * HZ);
142
143	/* We must enable before we kick off the timer in case the timer
144	   occurs as we ping it */
145
146	wdt_change(WDT_ENABLE);
147
148	/* Start the timer */
149	mod_timer(&timer, jiffies + WDT_INTERVAL);
150
151	printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
152}
153
154static void wdt_turnoff(void)
155{
156	/* Stop the timer */
157	del_timer_sync(&timer);
158	wdt_change(WDT_DISABLE);
159	printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
160}
161
162static void wdt_keepalive(void)
163{
164	/* user land ping */
165	next_heartbeat = jiffies + (timeout * HZ);
166}
167
168/*
169 * /dev/watchdog handling
170 */
171
172static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos)
173{
174	/* See if we got the magic character 'V' and reload the timer */
175	if(count) {
176		if (!nowayout) {
177			size_t ofs;
178
179			/* note: just in case someone wrote the magic character
180			 * five months ago... */
181			wdt_expect_close = 0;
182
183			/* now scan */
184			for (ofs = 0; ofs != count; ofs++) {
185				char c;
186				if (get_user(c, buf+ofs))
187					return -EFAULT;
188				if (c == 'V')
189					wdt_expect_close = 42;
190			}
191		}
192		/* someone wrote to us, we should restart timer */
193		wdt_keepalive();
194	}
195	return count;
196}
197
198static int fop_open(struct inode * inode, struct file * file)
199{
200	/* Just in case we're already talking to someone... */
201	if(test_and_set_bit(0, &wdt_is_open))
202		return -EBUSY;
203	/* Good, fire up the show */
204	wdt_startup();
205	return nonseekable_open(inode, file);
206}
207
208static int fop_close(struct inode * inode, struct file * file)
209{
210	if(wdt_expect_close == 42)
211		wdt_turnoff();
212	else {
213		/* wim: shouldn't there be a: del_timer(&timer); */
214		printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
215	}
216	clear_bit(0, &wdt_is_open);
217	wdt_expect_close = 0;
218	return 0;
219}
220
221static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
222{
223	void __user *argp = (void __user *)arg;
224	int __user *p = argp;
225	static struct watchdog_info ident =
226	{
227		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
228		.firmware_version = 1,
229		.identity = "ALiM7101",
230	};
231
232	switch(cmd)
233	{
234		case WDIOC_GETSUPPORT:
235			return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;
236		case WDIOC_GETSTATUS:
237		case WDIOC_GETBOOTSTATUS:
238			return put_user(0, p);
239		case WDIOC_KEEPALIVE:
240			wdt_keepalive();
241			return 0;
242		case WDIOC_SETOPTIONS:
243		{
244			int new_options, retval = -EINVAL;
245
246			if(get_user(new_options, p))
247				return -EFAULT;
248
249			if(new_options & WDIOS_DISABLECARD) {
250				wdt_turnoff();
251				retval = 0;
252			}
253
254			if(new_options & WDIOS_ENABLECARD) {
255				wdt_startup();
256				retval = 0;
257			}
258
259			return retval;
260		}
261		case WDIOC_SETTIMEOUT:
262		{
263			int new_timeout;
264
265			if(get_user(new_timeout, p))
266				return -EFAULT;
267
268			if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
269				return -EINVAL;
270
271			timeout = new_timeout;
272			wdt_keepalive();
273			/* Fall through */
274		}
275		case WDIOC_GETTIMEOUT:
276			return put_user(timeout, p);
277		default:
278			return -ENOTTY;
279	}
280}
281
282static const struct file_operations wdt_fops = {
283	.owner=		THIS_MODULE,
284	.llseek=	no_llseek,
285	.write=		fop_write,
286	.open=		fop_open,
287	.release=	fop_close,
288	.ioctl=		fop_ioctl,
289};
290
291static struct miscdevice wdt_miscdev = {
292	.minor=WATCHDOG_MINOR,
293	.name="watchdog",
294	.fops=&wdt_fops,
295};
296
297/*
298 *	Notifier for system down
299 */
300
301static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
302{
303	if (code==SYS_DOWN || code==SYS_HALT)
304		wdt_turnoff();
305
306	if (code==SYS_RESTART) {
307		/*
308		 * Cobalt devices have no way of rebooting themselves other than
309		 * getting the watchdog to pull reset, so we restart the watchdog on
310		 * reboot with no heartbeat
311		 */
312		wdt_change(WDT_ENABLE);
313		printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n");
314	}
315	return NOTIFY_DONE;
316}
317
318/*
319 *	The WDT needs to learn about soft shutdowns in order to
320 *	turn the timebomb registers off.
321 */
322
323static struct notifier_block wdt_notifier=
324{
325	.notifier_call = wdt_notify_sys,
326};
327
328static void __exit alim7101_wdt_unload(void)
329{
330	wdt_turnoff();
331	/* Deregister */
332	misc_deregister(&wdt_miscdev);
333	unregister_reboot_notifier(&wdt_notifier);
334	pci_dev_put(alim7101_pmu);
335}
336
337static int __init alim7101_wdt_init(void)
338{
339	int rc = -EBUSY;
340	struct pci_dev *ali1543_south;
341	char tmp;
342
343	printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");
344	alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
345		NULL);
346	if (!alim7101_pmu) {
347		printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n");
348		return -EBUSY;
349	}
350
351	/* Set the WDT in the PMU to 1 second */
352	pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
353
354	ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
355		NULL);
356	if (!ali1543_south) {
357		printk(KERN_INFO PFX "ALi 1543 South-Bridge not present - WDT not set\n");
358		goto err_out;
359	}
360	pci_read_config_byte(ali1543_south, 0x5e, &tmp);
361	pci_dev_put(ali1543_south);
362	if ((tmp & 0x1e) == 0x00) {
363		if (!use_gpio) {
364			printk(KERN_INFO PFX "Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
365			goto err_out;
366		}
367		nowayout = 1;
368	} else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
369		printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
370		goto err_out;
371	}
372
373	if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
374	{
375		timeout = WATCHDOG_TIMEOUT;
376		printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
377			timeout);
378	}
379
380	rc = misc_register(&wdt_miscdev);
381	if (rc) {
382		printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
383			wdt_miscdev.minor, rc);
384		goto err_out;
385	}
386
387	rc = register_reboot_notifier(&wdt_notifier);
388	if (rc) {
389		printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
390			rc);
391		goto err_out_miscdev;
392	}
393
394	if (nowayout) {
395		__module_get(THIS_MODULE);
396	}
397
398	printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
399		timeout, nowayout);
400	return 0;
401
402err_out_miscdev:
403	misc_deregister(&wdt_miscdev);
404err_out:
405	pci_dev_put(alim7101_pmu);
406	return rc;
407}
408
409module_init(alim7101_wdt_init);
410module_exit(alim7101_wdt_unload);
411
412static struct pci_device_id alim7101_pci_tbl[] __devinitdata = {
413	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
414	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
415	{ }
416};
417
418MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
419
420MODULE_AUTHOR("Steve Hill");
421MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
422MODULE_LICENSE("GPL");
423MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
424