1/*
2 *	nv_tco 0.01:	TCO timer driver for NV chipsets
3 *
4 *	(c) Copyright 2005 Google Inc., All Rights Reserved.
5 *
6 *	Based off i8xx_tco.c:
7 *	(c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
8 *	Reserved.
9 *				http://www.kernelconcepts.de
10 *
11 *	This program is free software; you can redistribute it and/or
12 *	modify it under the terms of the GNU General Public License
13 *	as published by the Free Software Foundation; either version
14 *	2 of the License, or (at your option) any later version.
15 *
16 *	TCO timer driver for NV chipsets
17 *	based on softdog.c by Alan Cox <alan@redhat.com>
18 */
19
20/*
21 *	Includes, defines, variables, module parameters, ...
22 */
23
24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/types.h>
29#include <linux/miscdevice.h>
30#include <linux/watchdog.h>
31#include <linux/init.h>
32#include <linux/fs.h>
33#include <linux/pci.h>
34#include <linux/ioport.h>
35#include <linux/jiffies.h>
36#include <linux/platform_device.h>
37#include <linux/uaccess.h>
38#include <linux/io.h>
39
40#include "nv_tco.h"
41
42/* Module and version information */
43#define TCO_VERSION "0.01"
44#define TCO_MODULE_NAME "NV_TCO"
45#define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
46
47/* internal variables */
48static unsigned int tcobase;
49static DEFINE_SPINLOCK(tco_lock);	/* Guards the hardware */
50static unsigned long timer_alive;
51static char tco_expect_close;
52static struct pci_dev *tco_pci;
53
54/* the watchdog platform device */
55static struct platform_device *nv_tco_platform_device;
56
57/* module parameters */
58#define WATCHDOG_HEARTBEAT 30	/* 30 sec default heartbeat (2<heartbeat<39) */
59static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
60module_param(heartbeat, int, 0);
61MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
62			    "default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
63
64static bool nowayout = WATCHDOG_NOWAYOUT;
65module_param(nowayout, bool, 0);
66MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
67		" (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
68
69/*
70 * Some TCO specific functions
71 */
72static inline unsigned char seconds_to_ticks(int seconds)
73{
74	/* the internal timer is stored as ticks which decrement
75	 * every 0.6 seconds */
76	return (seconds * 10) / 6;
77}
78
79static void tco_timer_start(void)
80{
81	u32 val;
82	unsigned long flags;
83
84	spin_lock_irqsave(&tco_lock, flags);
85	val = inl(TCO_CNT(tcobase));
86	val &= ~TCO_CNT_TCOHALT;
87	outl(val, TCO_CNT(tcobase));
88	spin_unlock_irqrestore(&tco_lock, flags);
89}
90
91static void tco_timer_stop(void)
92{
93	u32 val;
94	unsigned long flags;
95
96	spin_lock_irqsave(&tco_lock, flags);
97	val = inl(TCO_CNT(tcobase));
98	val |= TCO_CNT_TCOHALT;
99	outl(val, TCO_CNT(tcobase));
100	spin_unlock_irqrestore(&tco_lock, flags);
101}
102
103static void tco_timer_keepalive(void)
104{
105	unsigned long flags;
106
107	spin_lock_irqsave(&tco_lock, flags);
108	outb(0x01, TCO_RLD(tcobase));
109	spin_unlock_irqrestore(&tco_lock, flags);
110}
111
112static int tco_timer_set_heartbeat(int t)
113{
114	int ret = 0;
115	unsigned char tmrval;
116	unsigned long flags;
117	u8 val;
118
119	/*
120	 * note seconds_to_ticks(t) > t, so if t > 0x3f, so is
121	 * tmrval=seconds_to_ticks(t).  Check that the count in seconds isn't
122	 * out of range on it's own (to avoid overflow in tmrval).
123	 */
124	if (t < 0 || t > 0x3f)
125		return -EINVAL;
126	tmrval = seconds_to_ticks(t);
127
128	/* "Values of 0h-3h are ignored and should not be attempted" */
129	if (tmrval > 0x3f || tmrval < 0x04)
130		return -EINVAL;
131
132	/* Write new heartbeat to watchdog */
133	spin_lock_irqsave(&tco_lock, flags);
134	val = inb(TCO_TMR(tcobase));
135	val &= 0xc0;
136	val |= tmrval;
137	outb(val, TCO_TMR(tcobase));
138	val = inb(TCO_TMR(tcobase));
139
140	if ((val & 0x3f) != tmrval)
141		ret = -EINVAL;
142	spin_unlock_irqrestore(&tco_lock, flags);
143
144	if (ret)
145		return ret;
146
147	heartbeat = t;
148	return 0;
149}
150
151/*
152 *	/dev/watchdog handling
153 */
154
155static int nv_tco_open(struct inode *inode, struct file *file)
156{
157	/* /dev/watchdog can only be opened once */
158	if (test_and_set_bit(0, &timer_alive))
159		return -EBUSY;
160
161	/* Reload and activate timer */
162	tco_timer_keepalive();
163	tco_timer_start();
164	return nonseekable_open(inode, file);
165}
166
167static int nv_tco_release(struct inode *inode, struct file *file)
168{
169	/* Shut off the timer */
170	if (tco_expect_close == 42) {
171		tco_timer_stop();
172	} else {
173		pr_crit("Unexpected close, not stopping watchdog!\n");
174		tco_timer_keepalive();
175	}
176	clear_bit(0, &timer_alive);
177	tco_expect_close = 0;
178	return 0;
179}
180
181static ssize_t nv_tco_write(struct file *file, const char __user *data,
182			    size_t len, loff_t *ppos)
183{
184	/* See if we got the magic character 'V' and reload the timer */
185	if (len) {
186		if (!nowayout) {
187			size_t i;
188
189			/*
190			 * note: just in case someone wrote the magic character
191			 * five months ago...
192			 */
193			tco_expect_close = 0;
194
195			/*
196			 * scan to see whether or not we got the magic
197			 * character
198			 */
199			for (i = 0; i != len; i++) {
200				char c;
201				if (get_user(c, data + i))
202					return -EFAULT;
203				if (c == 'V')
204					tco_expect_close = 42;
205			}
206		}
207
208		/* someone wrote to us, we should reload the timer */
209		tco_timer_keepalive();
210	}
211	return len;
212}
213
214static long nv_tco_ioctl(struct file *file, unsigned int cmd,
215			 unsigned long arg)
216{
217	int new_options, retval = -EINVAL;
218	int new_heartbeat;
219	void __user *argp = (void __user *)arg;
220	int __user *p = argp;
221	static const struct watchdog_info ident = {
222		.options =		WDIOF_SETTIMEOUT |
223					WDIOF_KEEPALIVEPING |
224					WDIOF_MAGICCLOSE,
225		.firmware_version =	0,
226		.identity =		TCO_MODULE_NAME,
227	};
228
229	switch (cmd) {
230	case WDIOC_GETSUPPORT:
231		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
232	case WDIOC_GETSTATUS:
233	case WDIOC_GETBOOTSTATUS:
234		return put_user(0, p);
235	case WDIOC_SETOPTIONS:
236		if (get_user(new_options, p))
237			return -EFAULT;
238		if (new_options & WDIOS_DISABLECARD) {
239			tco_timer_stop();
240			retval = 0;
241		}
242		if (new_options & WDIOS_ENABLECARD) {
243			tco_timer_keepalive();
244			tco_timer_start();
245			retval = 0;
246		}
247		return retval;
248	case WDIOC_KEEPALIVE:
249		tco_timer_keepalive();
250		return 0;
251	case WDIOC_SETTIMEOUT:
252		if (get_user(new_heartbeat, p))
253			return -EFAULT;
254		if (tco_timer_set_heartbeat(new_heartbeat))
255			return -EINVAL;
256		tco_timer_keepalive();
257		/* Fall through */
258	case WDIOC_GETTIMEOUT:
259		return put_user(heartbeat, p);
260	default:
261		return -ENOTTY;
262	}
263}
264
265/*
266 *	Kernel Interfaces
267 */
268
269static const struct file_operations nv_tco_fops = {
270	.owner =		THIS_MODULE,
271	.llseek =		no_llseek,
272	.write =		nv_tco_write,
273	.unlocked_ioctl =	nv_tco_ioctl,
274	.open =			nv_tco_open,
275	.release =		nv_tco_release,
276};
277
278static struct miscdevice nv_tco_miscdev = {
279	.minor =	WATCHDOG_MINOR,
280	.name =		"watchdog",
281	.fops =		&nv_tco_fops,
282};
283
284/*
285 * Data for PCI driver interface
286 *
287 * This data only exists for exporting the supported
288 * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
289 * register a pci_driver, because someone else might one day
290 * want to register another driver on the same PCI id.
291 */
292static const struct pci_device_id tco_pci_tbl[] = {
293	{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS,
294	  PCI_ANY_ID, PCI_ANY_ID, },
295	{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS,
296	  PCI_ANY_ID, PCI_ANY_ID, },
297	{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_SMBUS,
298	  PCI_ANY_ID, PCI_ANY_ID, },
299	{ 0, },			/* End of list */
300};
301MODULE_DEVICE_TABLE(pci, tco_pci_tbl);
302
303/*
304 *	Init & exit routines
305 */
306
307static unsigned char nv_tco_getdevice(void)
308{
309	struct pci_dev *dev = NULL;
310	u32 val;
311
312	/* Find the PCI device */
313	for_each_pci_dev(dev) {
314		if (pci_match_id(tco_pci_tbl, dev) != NULL) {
315			tco_pci = dev;
316			break;
317		}
318	}
319
320	if (!tco_pci)
321		return 0;
322
323	/* Find the base io port */
324	pci_read_config_dword(tco_pci, 0x64, &val);
325	val &= 0xffff;
326	if (val == 0x0001 || val == 0x0000) {
327		/* Something is wrong here, bar isn't setup */
328		pr_err("failed to get tcobase address\n");
329		return 0;
330	}
331	val &= 0xff00;
332	tcobase = val + 0x40;
333
334	if (!request_region(tcobase, 0x10, "NV TCO")) {
335		pr_err("I/O address 0x%04x already in use\n", tcobase);
336		return 0;
337	}
338
339	/* Set a reasonable heartbeat before we stop the timer */
340	tco_timer_set_heartbeat(30);
341
342	/*
343	 * Stop the TCO before we change anything so we don't race with
344	 * a zeroed timer.
345	 */
346	tco_timer_keepalive();
347	tco_timer_stop();
348
349	/* Disable SMI caused by TCO */
350	if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) {
351		pr_err("I/O address 0x%04x already in use\n",
352		       MCP51_SMI_EN(tcobase));
353		goto out;
354	}
355	val = inl(MCP51_SMI_EN(tcobase));
356	val &= ~MCP51_SMI_EN_TCO;
357	outl(val, MCP51_SMI_EN(tcobase));
358	val = inl(MCP51_SMI_EN(tcobase));
359	release_region(MCP51_SMI_EN(tcobase), 4);
360	if (val & MCP51_SMI_EN_TCO) {
361		pr_err("Could not disable SMI caused by TCO\n");
362		goto out;
363	}
364
365	/* Check chipset's NO_REBOOT bit */
366	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
367	val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT;
368	pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
369	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
370	if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) {
371		pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n");
372		goto out;
373	}
374
375	return 1;
376out:
377	release_region(tcobase, 0x10);
378	return 0;
379}
380
381static int nv_tco_init(struct platform_device *dev)
382{
383	int ret;
384
385	/* Check whether or not the hardware watchdog is there */
386	if (!nv_tco_getdevice())
387		return -ENODEV;
388
389	/* Check to see if last reboot was due to watchdog timeout */
390	pr_info("Watchdog reboot %sdetected\n",
391		inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not ");
392
393	/* Clear out the old status */
394	outl(TCO_STS_RESET, TCO_STS(tcobase));
395
396	/*
397	 * Check that the heartbeat value is within it's range.
398	 * If not, reset to the default.
399	 */
400	if (tco_timer_set_heartbeat(heartbeat)) {
401		heartbeat = WATCHDOG_HEARTBEAT;
402		tco_timer_set_heartbeat(heartbeat);
403		pr_info("heartbeat value must be 2<heartbeat<39, using %d\n",
404			heartbeat);
405	}
406
407	ret = misc_register(&nv_tco_miscdev);
408	if (ret != 0) {
409		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
410		       WATCHDOG_MINOR, ret);
411		goto unreg_region;
412	}
413
414	clear_bit(0, &timer_alive);
415
416	tco_timer_stop();
417
418	pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n",
419		tcobase, heartbeat, nowayout);
420
421	return 0;
422
423unreg_region:
424	release_region(tcobase, 0x10);
425	return ret;
426}
427
428static void nv_tco_cleanup(void)
429{
430	u32 val;
431
432	/* Stop the timer before we leave */
433	if (!nowayout)
434		tco_timer_stop();
435
436	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
437	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
438	val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
439	pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
440	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
441	if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) {
442		pr_crit("Couldn't unset REBOOT bit.  Machine may soon reset\n");
443	}
444
445	/* Deregister */
446	misc_deregister(&nv_tco_miscdev);
447	release_region(tcobase, 0x10);
448}
449
450static int nv_tco_remove(struct platform_device *dev)
451{
452	if (tcobase)
453		nv_tco_cleanup();
454
455	return 0;
456}
457
458static void nv_tco_shutdown(struct platform_device *dev)
459{
460	u32 val;
461
462	tco_timer_stop();
463
464	/* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not
465	 * unset during shutdown. */
466	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
467	val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
468	pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
469}
470
471static struct platform_driver nv_tco_driver = {
472	.probe		= nv_tco_init,
473	.remove		= nv_tco_remove,
474	.shutdown	= nv_tco_shutdown,
475	.driver		= {
476		.name	= TCO_MODULE_NAME,
477	},
478};
479
480static int __init nv_tco_init_module(void)
481{
482	int err;
483
484	pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION);
485
486	err = platform_driver_register(&nv_tco_driver);
487	if (err)
488		return err;
489
490	nv_tco_platform_device = platform_device_register_simple(
491					TCO_MODULE_NAME, -1, NULL, 0);
492	if (IS_ERR(nv_tco_platform_device)) {
493		err = PTR_ERR(nv_tco_platform_device);
494		goto unreg_platform_driver;
495	}
496
497	return 0;
498
499unreg_platform_driver:
500	platform_driver_unregister(&nv_tco_driver);
501	return err;
502}
503
504static void __exit nv_tco_cleanup_module(void)
505{
506	platform_device_unregister(nv_tco_platform_device);
507	platform_driver_unregister(&nv_tco_driver);
508	pr_info("NV TCO Watchdog Module Unloaded\n");
509}
510
511module_init(nv_tco_init_module);
512module_exit(nv_tco_cleanup_module);
513
514MODULE_AUTHOR("Mike Waychison");
515MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
516MODULE_LICENSE("GPL");
517