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/drivers/watchdog/alim1535_wdt.c

https://bitbucket.org/cyanogenmod/android_kernel_asus_tf300t
C | 458 lines | 259 code | 69 blank | 130 comment | 43 complexity | bae687b511dd9aa8599af8cb0e34a9f7 MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
  1/*
  2 *	Watchdog for the 7101 PMU version found in the ALi M1535 chipsets
  3 *
  4 *	This program is free software; you can redistribute it and/or
  5 *	modify it under the terms of the GNU General Public License
  6 *	as published by the Free Software Foundation; either version
  7 *	2 of the License, or (at your option) any later version.
  8 */
  9
 10#include <linux/module.h>
 11#include <linux/moduleparam.h>
 12#include <linux/types.h>
 13#include <linux/miscdevice.h>
 14#include <linux/watchdog.h>
 15#include <linux/ioport.h>
 16#include <linux/notifier.h>
 17#include <linux/reboot.h>
 18#include <linux/init.h>
 19#include <linux/fs.h>
 20#include <linux/pci.h>
 21#include <linux/uaccess.h>
 22#include <linux/io.h>
 23
 24#define WATCHDOG_NAME "ALi_M1535"
 25#define PFX WATCHDOG_NAME ": "
 26#define WATCHDOG_TIMEOUT 60	/* 60 sec default timeout */
 27
 28/* internal variables */
 29static unsigned long ali_is_open;
 30static char ali_expect_release;
 31static struct pci_dev *ali_pci;
 32static u32 ali_timeout_bits;		/* stores the computed timeout */
 33static DEFINE_SPINLOCK(ali_lock);	/* Guards the hardware */
 34
 35/* module parameters */
 36static int timeout = WATCHDOG_TIMEOUT;
 37module_param(timeout, int, 0);
 38MODULE_PARM_DESC(timeout,
 39		"Watchdog timeout in seconds. (0 < timeout < 18000, default="
 40				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
 41
 42static int nowayout = WATCHDOG_NOWAYOUT;
 43module_param(nowayout, int, 0);
 44MODULE_PARM_DESC(nowayout,
 45		"Watchdog cannot be stopped once started (default="
 46				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 47
 48/*
 49 *	ali_start	-	start watchdog countdown
 50 *
 51 *	Starts the timer running providing the timer has a counter
 52 *	configuration set.
 53 */
 54
 55static void ali_start(void)
 56{
 57	u32 val;
 58
 59	spin_lock(&ali_lock);
 60
 61	pci_read_config_dword(ali_pci, 0xCC, &val);
 62	val &= ~0x3F;	/* Mask count */
 63	val |= (1 << 25) | ali_timeout_bits;
 64	pci_write_config_dword(ali_pci, 0xCC, val);
 65
 66	spin_unlock(&ali_lock);
 67}
 68
 69/*
 70 *	ali_stop	-	stop the timer countdown
 71 *
 72 *	Stop the ALi watchdog countdown
 73 */
 74
 75static void ali_stop(void)
 76{
 77	u32 val;
 78
 79	spin_lock(&ali_lock);
 80
 81	pci_read_config_dword(ali_pci, 0xCC, &val);
 82	val &= ~0x3F;		/* Mask count to zero (disabled) */
 83	val &= ~(1 << 25);	/* and for safety mask the reset enable */
 84	pci_write_config_dword(ali_pci, 0xCC, val);
 85
 86	spin_unlock(&ali_lock);
 87}
 88
 89/*
 90 *	ali_keepalive	-	send a keepalive to the watchdog
 91 *
 92 *	Send a keepalive to the timer (actually we restart the timer).
 93 */
 94
 95static void ali_keepalive(void)
 96{
 97	ali_start();
 98}
 99
100/*
101 *	ali_settimer	-	compute the timer reload value
102 *	@t: time in seconds
103 *
104 *	Computes the timeout values needed
105 */
106
107static int ali_settimer(int t)
108{
109	if (t < 0)
110		return -EINVAL;
111	else if (t < 60)
112		ali_timeout_bits = t|(1 << 6);
113	else if (t < 3600)
114		ali_timeout_bits = (t / 60)|(1 << 7);
115	else if (t < 18000)
116		ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7);
117	else
118		return -EINVAL;
119
120	timeout = t;
121	return 0;
122}
123
124/*
125 *	/dev/watchdog handling
126 */
127
128/*
129 *	ali_write	-	writes to ALi watchdog
130 *	@file: file from VFS
131 *	@data: user address of data
132 *	@len: length of data
133 *	@ppos: pointer to the file offset
134 *
135 *	Handle a write to the ALi watchdog. Writing to the file pings
136 *	the watchdog and resets it. Writing the magic 'V' sequence allows
137 *	the next close to turn off the watchdog.
138 */
139
140static ssize_t ali_write(struct file *file, const char __user *data,
141						size_t len, loff_t *ppos)
142{
143	/* See if we got the magic character 'V' and reload the timer */
144	if (len) {
145		if (!nowayout) {
146			size_t i;
147
148			/* note: just in case someone wrote the
149			   magic character five months ago... */
150			ali_expect_release = 0;
151
152			/* scan to see whether or not we got
153			   the magic character */
154			for (i = 0; i != len; i++) {
155				char c;
156				if (get_user(c, data + i))
157					return -EFAULT;
158				if (c == 'V')
159					ali_expect_release = 42;
160			}
161		}
162
163		/* someone wrote to us, we should reload the timer */
164		ali_start();
165	}
166	return len;
167}
168
169/*
170 *	ali_ioctl	-	handle watchdog ioctls
171 *	@file: VFS file pointer
172 *	@cmd: ioctl number
173 *	@arg: arguments to the ioctl
174 *
175 *	Handle the watchdog ioctls supported by the ALi driver. Really
176 *	we want an extension to enable irq ack monitoring and the like
177 */
178
179static long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
180{
181	void __user *argp = (void __user *)arg;
182	int __user *p = argp;
183	static const struct watchdog_info ident = {
184		.options =		WDIOF_KEEPALIVEPING |
185					WDIOF_SETTIMEOUT |
186					WDIOF_MAGICCLOSE,
187		.firmware_version =	0,
188		.identity =		"ALi M1535 WatchDog Timer",
189	};
190
191	switch (cmd) {
192	case WDIOC_GETSUPPORT:
193		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
194
195	case WDIOC_GETSTATUS:
196	case WDIOC_GETBOOTSTATUS:
197		return put_user(0, p);
198	case WDIOC_SETOPTIONS:
199	{
200		int new_options, retval = -EINVAL;
201
202		if (get_user(new_options, p))
203			return -EFAULT;
204		if (new_options & WDIOS_DISABLECARD) {
205			ali_stop();
206			retval = 0;
207		}
208		if (new_options & WDIOS_ENABLECARD) {
209			ali_start();
210			retval = 0;
211		}
212		return retval;
213	}
214	case WDIOC_KEEPALIVE:
215		ali_keepalive();
216		return 0;
217	case WDIOC_SETTIMEOUT:
218	{
219		int new_timeout;
220		if (get_user(new_timeout, p))
221			return -EFAULT;
222		if (ali_settimer(new_timeout))
223			return -EINVAL;
224		ali_keepalive();
225		/* Fall */
226	}
227	case WDIOC_GETTIMEOUT:
228		return put_user(timeout, p);
229	default:
230		return -ENOTTY;
231	}
232}
233
234/*
235 *	ali_open	-	handle open of ali watchdog
236 *	@inode: inode from VFS
237 *	@file: file from VFS
238 *
239 *	Open the ALi watchdog device. Ensure only one person opens it
240 *	at a time. Also start the watchdog running.
241 */
242
243static int ali_open(struct inode *inode, struct file *file)
244{
245	/* /dev/watchdog can only be opened once */
246	if (test_and_set_bit(0, &ali_is_open))
247		return -EBUSY;
248
249	/* Activate */
250	ali_start();
251	return nonseekable_open(inode, file);
252}
253
254/*
255 *	ali_release	-	close an ALi watchdog
256 *	@inode: inode from VFS
257 *	@file: file from VFS
258 *
259 *	Close the ALi watchdog device. Actual shutdown of the timer
260 *	only occurs if the magic sequence has been set.
261 */
262
263static int ali_release(struct inode *inode, struct file *file)
264{
265	/*
266	 *      Shut off the timer.
267	 */
268	if (ali_expect_release == 42)
269		ali_stop();
270	else {
271		printk(KERN_CRIT PFX
272				"Unexpected close, not stopping watchdog!\n");
273		ali_keepalive();
274	}
275	clear_bit(0, &ali_is_open);
276	ali_expect_release = 0;
277	return 0;
278}
279
280/*
281 *	ali_notify_sys	-	System down notifier
282 *
283 *	Notifier for system down
284 */
285
286
287static int ali_notify_sys(struct notifier_block *this,
288					unsigned long code, void *unused)
289{
290	if (code == SYS_DOWN || code == SYS_HALT)
291		ali_stop();		/* Turn the WDT off */
292	return NOTIFY_DONE;
293}
294
295/*
296 *	Data for PCI driver interface
297 *
298 *	This data only exists for exporting the supported
299 *	PCI ids via MODULE_DEVICE_TABLE.  We do not actually
300 *	register a pci_driver, because someone else might one day
301 *	want to register another driver on the same PCI id.
302 */
303
304static DEFINE_PCI_DEVICE_TABLE(ali_pci_tbl) __used = {
305	{ PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,},
306	{ PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,},
307	{ 0, },
308};
309MODULE_DEVICE_TABLE(pci, ali_pci_tbl);
310
311/*
312 *	ali_find_watchdog	-	find a 1535 and 7101
313 *
314 *	Scans the PCI hardware for a 1535 series bridge and matching 7101
315 *	watchdog device. This may be overtight but it is better to be safe
316 */
317
318static int __init ali_find_watchdog(void)
319{
320	struct pci_dev *pdev;
321	u32 wdog;
322
323	/* Check for a 1533/1535 series bridge */
324	pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL);
325	if (pdev == NULL)
326		pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL);
327	if (pdev == NULL)
328		return -ENODEV;
329	pci_dev_put(pdev);
330
331	/* Check for the a 7101 PMU */
332	pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL);
333	if (pdev == NULL)
334		return -ENODEV;
335
336	if (pci_enable_device(pdev)) {
337		pci_dev_put(pdev);
338		return -EIO;
339	}
340
341	ali_pci = pdev;
342
343	/*
344	 *	Initialize the timer bits
345	 */
346	pci_read_config_dword(pdev, 0xCC, &wdog);
347
348	/* Timer bits */
349	wdog &= ~0x3F;
350	/* Issued events */
351	wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24));
352	/* No monitor bits */
353	wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9));
354
355	pci_write_config_dword(pdev, 0xCC, wdog);
356
357	return 0;
358}
359
360/*
361 *	Kernel Interfaces
362 */
363
364static const struct file_operations ali_fops = {
365	.owner		=	THIS_MODULE,
366	.llseek		=	no_llseek,
367	.write		=	ali_write,
368	.unlocked_ioctl =	ali_ioctl,
369	.open		=	ali_open,
370	.release	=	ali_release,
371};
372
373static struct miscdevice ali_miscdev = {
374	.minor =	WATCHDOG_MINOR,
375	.name =		"watchdog",
376	.fops =		&ali_fops,
377};
378
379static struct notifier_block ali_notifier = {
380	.notifier_call =	ali_notify_sys,
381};
382
383/*
384 *	watchdog_init	-	module initialiser
385 *
386 *	Scan for a suitable watchdog and if so initialize it. Return an error
387 *	if we cannot, the error causes the module to unload
388 */
389
390static int __init watchdog_init(void)
391{
392	int ret;
393
394	/* Check whether or not the hardware watchdog is there */
395	if (ali_find_watchdog() != 0)
396		return -ENODEV;
397
398	/* Check that the timeout value is within it's range;
399	   if not reset to the default */
400	if (timeout < 1 || timeout >= 18000) {
401		timeout = WATCHDOG_TIMEOUT;
402		printk(KERN_INFO PFX
403		     "timeout value must be 0 < timeout < 18000, using %d\n",
404							timeout);
405	}
406
407	/* Calculate the watchdog's timeout */
408	ali_settimer(timeout);
409
410	ret = register_reboot_notifier(&ali_notifier);
411	if (ret != 0) {
412		printk(KERN_ERR PFX
413			"cannot register reboot notifier (err=%d)\n", ret);
414		goto out;
415	}
416
417	ret = misc_register(&ali_miscdev);
418	if (ret != 0) {
419		printk(KERN_ERR PFX
420			"cannot register miscdev on minor=%d (err=%d)\n",
421						WATCHDOG_MINOR, ret);
422		goto unreg_reboot;
423	}
424
425	printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
426		timeout, nowayout);
427
428out:
429	return ret;
430unreg_reboot:
431	unregister_reboot_notifier(&ali_notifier);
432	goto out;
433}
434
435/*
436 *	watchdog_exit	-	module de-initialiser
437 *
438 *	Called while unloading a successfully installed watchdog module.
439 */
440
441static void __exit watchdog_exit(void)
442{
443	/* Stop the timer before we leave */
444	ali_stop();
445
446	/* Deregister */
447	misc_deregister(&ali_miscdev);
448	unregister_reboot_notifier(&ali_notifier);
449	pci_dev_put(ali_pci);
450}
451
452module_init(watchdog_init);
453module_exit(watchdog_exit);
454
455MODULE_AUTHOR("Alan Cox");
456MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");
457MODULE_LICENSE("GPL");
458MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);