xref: /openbmc/linux/drivers/watchdog/iTCO_wdt.c (revision 52cdded0)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *	intel TCO Watchdog Driver
4  *
5  *	(c) Copyright 2006-2011 Wim Van Sebroeck <wim@iguana.be>.
6  *
7  *	Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
8  *	provide warranty for any of this software. This material is
9  *	provided "AS-IS" and at no charge.
10  *
11  *	The TCO watchdog is implemented in the following I/O controller hubs:
12  *	(See the intel documentation on http://developer.intel.com.)
13  *	document number 290655-003, 290677-014: 82801AA (ICH), 82801AB (ICHO)
14  *	document number 290687-002, 298242-027: 82801BA (ICH2)
15  *	document number 290733-003, 290739-013: 82801CA (ICH3-S)
16  *	document number 290716-001, 290718-007: 82801CAM (ICH3-M)
17  *	document number 290744-001, 290745-025: 82801DB (ICH4)
18  *	document number 252337-001, 252663-008: 82801DBM (ICH4-M)
19  *	document number 273599-001, 273645-002: 82801E (C-ICH)
20  *	document number 252516-001, 252517-028: 82801EB (ICH5), 82801ER (ICH5R)
21  *	document number 300641-004, 300884-013: 6300ESB
22  *	document number 301473-002, 301474-026: 82801F (ICH6)
23  *	document number 313082-001, 313075-006: 631xESB, 632xESB
24  *	document number 307013-003, 307014-024: 82801G (ICH7)
25  *	document number 322896-001, 322897-001: NM10
26  *	document number 313056-003, 313057-017: 82801H (ICH8)
27  *	document number 316972-004, 316973-012: 82801I (ICH9)
28  *	document number 319973-002, 319974-002: 82801J (ICH10)
29  *	document number 322169-001, 322170-003: 5 Series, 3400 Series (PCH)
30  *	document number 320066-003, 320257-008: EP80597 (IICH)
31  *	document number 324645-001, 324646-001: Cougar Point (CPT)
32  *	document number TBD                   : Patsburg (PBG)
33  *	document number TBD                   : DH89xxCC
34  *	document number TBD                   : Panther Point
35  *	document number TBD                   : Lynx Point
36  *	document number TBD                   : Lynx Point-LP
37  */
38 
39 /*
40  *	Includes, defines, variables, module parameters, ...
41  */
42 
43 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
44 
45 /* Module and version information */
46 #define DRV_NAME	"iTCO_wdt"
47 #define DRV_VERSION	"1.11"
48 
49 /* Includes */
50 #include <linux/acpi.h>			/* For ACPI support */
51 #include <linux/bits.h>			/* For BIT() */
52 #include <linux/module.h>		/* For module specific items */
53 #include <linux/moduleparam.h>		/* For new moduleparam's */
54 #include <linux/types.h>		/* For standard types (like size_t) */
55 #include <linux/errno.h>		/* For the -ENODEV/... values */
56 #include <linux/kernel.h>		/* For printk/panic/... */
57 #include <linux/watchdog.h>		/* For the watchdog specific items */
58 #include <linux/init.h>			/* For __init/__exit/... */
59 #include <linux/fs.h>			/* For file operations */
60 #include <linux/platform_device.h>	/* For platform_driver framework */
61 #include <linux/pci.h>			/* For pci functions */
62 #include <linux/ioport.h>		/* For io-port access */
63 #include <linux/spinlock.h>		/* For spin_lock/spin_unlock/... */
64 #include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
65 #include <linux/io.h>			/* For inb/outb/... */
66 #include <linux/platform_data/itco_wdt.h>
67 #include <linux/mfd/intel_pmc_bxt.h>
68 
69 #include "iTCO_vendor.h"
70 
71 /* Address definitions for the TCO */
72 /* TCO base address */
73 #define TCOBASE(p)	((p)->tco_res->start)
74 /* SMI Control and Enable Register */
75 #define SMI_EN(p)	((p)->smi_res->start)
76 
77 #define TCO_RLD(p)	(TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */
78 #define TCOv1_TMR(p)	(TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/
79 #define TCO_DAT_IN(p)	(TCOBASE(p) + 0x02) /* TCO Data In Register	*/
80 #define TCO_DAT_OUT(p)	(TCOBASE(p) + 0x03) /* TCO Data Out Register	*/
81 #define TCO1_STS(p)	(TCOBASE(p) + 0x04) /* TCO1 Status Register	*/
82 #define TCO2_STS(p)	(TCOBASE(p) + 0x06) /* TCO2 Status Register	*/
83 #define TCO1_CNT(p)	(TCOBASE(p) + 0x08) /* TCO1 Control Register	*/
84 #define TCO2_CNT(p)	(TCOBASE(p) + 0x0a) /* TCO2 Control Register	*/
85 #define TCOv2_TMR(p)	(TCOBASE(p) + 0x12) /* TCOv2 Timer Initial Value*/
86 
87 /* internal variables */
88 struct iTCO_wdt_private {
89 	struct watchdog_device wddev;
90 
91 	/* TCO version/generation */
92 	unsigned int iTCO_version;
93 	struct resource *tco_res;
94 	struct resource *smi_res;
95 	/*
96 	 * NO_REBOOT flag is Memory-Mapped GCS register bit 5 (TCO version 2),
97 	 * or memory-mapped PMC register bit 4 (TCO version 3).
98 	 */
99 	struct resource *gcs_pmc_res;
100 	unsigned long __iomem *gcs_pmc;
101 	/* the lock for io operations */
102 	spinlock_t io_lock;
103 	/* the PCI-device */
104 	struct pci_dev *pci_dev;
105 	/* whether or not the watchdog has been suspended */
106 	bool suspended;
107 	/* no reboot API private data */
108 	void *no_reboot_priv;
109 	/* no reboot update function pointer */
110 	int (*update_no_reboot_bit)(void *p, bool set);
111 };
112 
113 /* module parameters */
114 #define WATCHDOG_TIMEOUT 30	/* 30 sec default heartbeat */
115 static int heartbeat = WATCHDOG_TIMEOUT;  /* in seconds */
116 module_param(heartbeat, int, 0);
117 MODULE_PARM_DESC(heartbeat, "Watchdog timeout in seconds. "
118 	"5..76 (TCO v1) or 3..614 (TCO v2), default="
119 				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
120 
121 static bool nowayout = WATCHDOG_NOWAYOUT;
122 module_param(nowayout, bool, 0);
123 MODULE_PARM_DESC(nowayout,
124 	"Watchdog cannot be stopped once started (default="
125 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
126 
127 static int turn_SMI_watchdog_clear_off = 1;
128 module_param(turn_SMI_watchdog_clear_off, int, 0);
129 MODULE_PARM_DESC(turn_SMI_watchdog_clear_off,
130 	"Turn off SMI clearing watchdog (depends on TCO-version)(default=1)");
131 
132 /*
133  * Some TCO specific functions
134  */
135 
136 /*
137  * The iTCO v1 and v2's internal timer is stored as ticks which decrement
138  * every 0.6 seconds.  v3's internal timer is stored as seconds (some
139  * datasheets incorrectly state 0.6 seconds).
140  */
141 static inline unsigned int seconds_to_ticks(struct iTCO_wdt_private *p,
142 					    int secs)
143 {
144 	return p->iTCO_version == 3 ? secs : (secs * 10) / 6;
145 }
146 
147 static inline unsigned int ticks_to_seconds(struct iTCO_wdt_private *p,
148 					    int ticks)
149 {
150 	return p->iTCO_version == 3 ? ticks : (ticks * 6) / 10;
151 }
152 
153 static inline u32 no_reboot_bit(struct iTCO_wdt_private *p)
154 {
155 	u32 enable_bit;
156 
157 	switch (p->iTCO_version) {
158 	case 5:
159 	case 3:
160 		enable_bit = 0x00000010;
161 		break;
162 	case 2:
163 		enable_bit = 0x00000020;
164 		break;
165 	case 4:
166 	case 1:
167 	default:
168 		enable_bit = 0x00000002;
169 		break;
170 	}
171 
172 	return enable_bit;
173 }
174 
175 static int update_no_reboot_bit_def(void *priv, bool set)
176 {
177 	return 0;
178 }
179 
180 static int update_no_reboot_bit_pci(void *priv, bool set)
181 {
182 	struct iTCO_wdt_private *p = priv;
183 	u32 val32 = 0, newval32 = 0;
184 
185 	pci_read_config_dword(p->pci_dev, 0xd4, &val32);
186 	if (set)
187 		val32 |= no_reboot_bit(p);
188 	else
189 		val32 &= ~no_reboot_bit(p);
190 	pci_write_config_dword(p->pci_dev, 0xd4, val32);
191 	pci_read_config_dword(p->pci_dev, 0xd4, &newval32);
192 
193 	/* make sure the update is successful */
194 	if (val32 != newval32)
195 		return -EIO;
196 
197 	return 0;
198 }
199 
200 static int update_no_reboot_bit_mem(void *priv, bool set)
201 {
202 	struct iTCO_wdt_private *p = priv;
203 	u32 val32 = 0, newval32 = 0;
204 
205 	val32 = readl(p->gcs_pmc);
206 	if (set)
207 		val32 |= no_reboot_bit(p);
208 	else
209 		val32 &= ~no_reboot_bit(p);
210 	writel(val32, p->gcs_pmc);
211 	newval32 = readl(p->gcs_pmc);
212 
213 	/* make sure the update is successful */
214 	if (val32 != newval32)
215 		return -EIO;
216 
217 	return 0;
218 }
219 
220 static int update_no_reboot_bit_cnt(void *priv, bool set)
221 {
222 	struct iTCO_wdt_private *p = priv;
223 	u16 val, newval;
224 
225 	val = inw(TCO1_CNT(p));
226 	if (set)
227 		val |= BIT(0);
228 	else
229 		val &= ~BIT(0);
230 	outw(val, TCO1_CNT(p));
231 	newval = inw(TCO1_CNT(p));
232 
233 	/* make sure the update is successful */
234 	return val != newval ? -EIO : 0;
235 }
236 
237 static int update_no_reboot_bit_pmc(void *priv, bool set)
238 {
239 	struct intel_pmc_dev *pmc = priv;
240 	u32 bits = PMC_CFG_NO_REBOOT_EN;
241 	u32 value = set ? bits : 0;
242 
243 	return intel_pmc_gcr_update(pmc, PMC_GCR_PMC_CFG_REG, bits, value);
244 }
245 
246 static void iTCO_wdt_no_reboot_bit_setup(struct iTCO_wdt_private *p,
247 					 struct platform_device *pdev,
248 					 struct itco_wdt_platform_data *pdata)
249 {
250 	if (pdata->no_reboot_use_pmc) {
251 		struct intel_pmc_dev *pmc = dev_get_drvdata(pdev->dev.parent);
252 
253 		p->update_no_reboot_bit = update_no_reboot_bit_pmc;
254 		p->no_reboot_priv = pmc;
255 		return;
256 	}
257 
258 	if (p->iTCO_version >= 6)
259 		p->update_no_reboot_bit = update_no_reboot_bit_cnt;
260 	else if (p->iTCO_version >= 2)
261 		p->update_no_reboot_bit = update_no_reboot_bit_mem;
262 	else if (p->iTCO_version == 1)
263 		p->update_no_reboot_bit = update_no_reboot_bit_pci;
264 	else
265 		p->update_no_reboot_bit = update_no_reboot_bit_def;
266 
267 	p->no_reboot_priv = p;
268 }
269 
270 static int iTCO_wdt_start(struct watchdog_device *wd_dev)
271 {
272 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
273 	unsigned int val;
274 
275 	spin_lock(&p->io_lock);
276 
277 	iTCO_vendor_pre_start(p->smi_res, wd_dev->timeout);
278 
279 	/* disable chipset's NO_REBOOT bit */
280 	if (p->update_no_reboot_bit(p->no_reboot_priv, false)) {
281 		spin_unlock(&p->io_lock);
282 		pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware/BIOS\n");
283 		return -EIO;
284 	}
285 
286 	/* Force the timer to its reload value by writing to the TCO_RLD
287 	   register */
288 	if (p->iTCO_version >= 2)
289 		outw(0x01, TCO_RLD(p));
290 	else if (p->iTCO_version == 1)
291 		outb(0x01, TCO_RLD(p));
292 
293 	/* Bit 11: TCO Timer Halt -> 0 = The TCO timer is enabled to count */
294 	val = inw(TCO1_CNT(p));
295 	val &= 0xf7ff;
296 	outw(val, TCO1_CNT(p));
297 	val = inw(TCO1_CNT(p));
298 	spin_unlock(&p->io_lock);
299 
300 	if (val & 0x0800)
301 		return -1;
302 	return 0;
303 }
304 
305 static int iTCO_wdt_stop(struct watchdog_device *wd_dev)
306 {
307 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
308 	unsigned int val;
309 
310 	spin_lock(&p->io_lock);
311 
312 	iTCO_vendor_pre_stop(p->smi_res);
313 
314 	/* Bit 11: TCO Timer Halt -> 1 = The TCO timer is disabled */
315 	val = inw(TCO1_CNT(p));
316 	val |= 0x0800;
317 	outw(val, TCO1_CNT(p));
318 	val = inw(TCO1_CNT(p));
319 
320 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
321 	p->update_no_reboot_bit(p->no_reboot_priv, true);
322 
323 	spin_unlock(&p->io_lock);
324 
325 	if ((val & 0x0800) == 0)
326 		return -1;
327 	return 0;
328 }
329 
330 static int iTCO_wdt_ping(struct watchdog_device *wd_dev)
331 {
332 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
333 
334 	spin_lock(&p->io_lock);
335 
336 	/* Reload the timer by writing to the TCO Timer Counter register */
337 	if (p->iTCO_version >= 2) {
338 		outw(0x01, TCO_RLD(p));
339 	} else if (p->iTCO_version == 1) {
340 		/* Reset the timeout status bit so that the timer
341 		 * needs to count down twice again before rebooting */
342 		outw(0x0008, TCO1_STS(p));	/* write 1 to clear bit */
343 
344 		outb(0x01, TCO_RLD(p));
345 	}
346 
347 	spin_unlock(&p->io_lock);
348 	return 0;
349 }
350 
351 static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
352 {
353 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
354 	unsigned int val16;
355 	unsigned char val8;
356 	unsigned int tmrval;
357 
358 	tmrval = seconds_to_ticks(p, t);
359 
360 	/* For TCO v1 the timer counts down twice before rebooting */
361 	if (p->iTCO_version == 1)
362 		tmrval /= 2;
363 
364 	/* from the specs: */
365 	/* "Values of 0h-3h are ignored and should not be attempted" */
366 	if (tmrval < 0x04)
367 		return -EINVAL;
368 	if ((p->iTCO_version >= 2 && tmrval > 0x3ff) ||
369 	    (p->iTCO_version == 1 && tmrval > 0x03f))
370 		return -EINVAL;
371 
372 	/* Write new heartbeat to watchdog */
373 	if (p->iTCO_version >= 2) {
374 		spin_lock(&p->io_lock);
375 		val16 = inw(TCOv2_TMR(p));
376 		val16 &= 0xfc00;
377 		val16 |= tmrval;
378 		outw(val16, TCOv2_TMR(p));
379 		val16 = inw(TCOv2_TMR(p));
380 		spin_unlock(&p->io_lock);
381 
382 		if ((val16 & 0x3ff) != tmrval)
383 			return -EINVAL;
384 	} else if (p->iTCO_version == 1) {
385 		spin_lock(&p->io_lock);
386 		val8 = inb(TCOv1_TMR(p));
387 		val8 &= 0xc0;
388 		val8 |= (tmrval & 0xff);
389 		outb(val8, TCOv1_TMR(p));
390 		val8 = inb(TCOv1_TMR(p));
391 		spin_unlock(&p->io_lock);
392 
393 		if ((val8 & 0x3f) != tmrval)
394 			return -EINVAL;
395 	}
396 
397 	wd_dev->timeout = t;
398 	return 0;
399 }
400 
401 static unsigned int iTCO_wdt_get_timeleft(struct watchdog_device *wd_dev)
402 {
403 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
404 	unsigned int val16;
405 	unsigned char val8;
406 	unsigned int time_left = 0;
407 
408 	/* read the TCO Timer */
409 	if (p->iTCO_version >= 2) {
410 		spin_lock(&p->io_lock);
411 		val16 = inw(TCO_RLD(p));
412 		val16 &= 0x3ff;
413 		spin_unlock(&p->io_lock);
414 
415 		time_left = ticks_to_seconds(p, val16);
416 	} else if (p->iTCO_version == 1) {
417 		spin_lock(&p->io_lock);
418 		val8 = inb(TCO_RLD(p));
419 		val8 &= 0x3f;
420 		if (!(inw(TCO1_STS(p)) & 0x0008))
421 			val8 += (inb(TCOv1_TMR(p)) & 0x3f);
422 		spin_unlock(&p->io_lock);
423 
424 		time_left = ticks_to_seconds(p, val8);
425 	}
426 	return time_left;
427 }
428 
429 /*
430  *	Kernel Interfaces
431  */
432 
433 static const struct watchdog_info ident = {
434 	.options =		WDIOF_SETTIMEOUT |
435 				WDIOF_KEEPALIVEPING |
436 				WDIOF_MAGICCLOSE,
437 	.firmware_version =	0,
438 	.identity =		DRV_NAME,
439 };
440 
441 static const struct watchdog_ops iTCO_wdt_ops = {
442 	.owner =		THIS_MODULE,
443 	.start =		iTCO_wdt_start,
444 	.stop =			iTCO_wdt_stop,
445 	.ping =			iTCO_wdt_ping,
446 	.set_timeout =		iTCO_wdt_set_timeout,
447 	.get_timeleft =		iTCO_wdt_get_timeleft,
448 };
449 
450 /*
451  *	Init & exit routines
452  */
453 
454 static int iTCO_wdt_probe(struct platform_device *pdev)
455 {
456 	struct device *dev = &pdev->dev;
457 	struct itco_wdt_platform_data *pdata = dev_get_platdata(dev);
458 	struct iTCO_wdt_private *p;
459 	unsigned long val32;
460 	int ret;
461 
462 	if (!pdata)
463 		return -ENODEV;
464 
465 	p = devm_kzalloc(dev, sizeof(*p), GFP_KERNEL);
466 	if (!p)
467 		return -ENOMEM;
468 
469 	spin_lock_init(&p->io_lock);
470 
471 	p->tco_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_TCO);
472 	if (!p->tco_res)
473 		return -ENODEV;
474 
475 	p->iTCO_version = pdata->version;
476 	p->pci_dev = to_pci_dev(dev->parent);
477 
478 	p->smi_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_SMI);
479 	if (p->smi_res) {
480 		/* The TCO logic uses the TCO_EN bit in the SMI_EN register */
481 		if (!devm_request_region(dev, p->smi_res->start,
482 					 resource_size(p->smi_res),
483 					 pdev->name)) {
484 			pr_err("I/O address 0x%04llx already in use, device disabled\n",
485 			       (u64)SMI_EN(p));
486 			return -EBUSY;
487 		}
488 	} else if (iTCO_vendorsupport ||
489 		   turn_SMI_watchdog_clear_off >= p->iTCO_version) {
490 		pr_err("SMI I/O resource is missing\n");
491 		return -ENODEV;
492 	}
493 
494 	iTCO_wdt_no_reboot_bit_setup(p, pdev, pdata);
495 
496 	/*
497 	 * Get the Memory-Mapped GCS or PMC register, we need it for the
498 	 * NO_REBOOT flag (TCO v2 and v3).
499 	 */
500 	if (p->iTCO_version >= 2 && p->iTCO_version < 6 &&
501 	    !pdata->no_reboot_use_pmc) {
502 		p->gcs_pmc_res = platform_get_resource(pdev,
503 						       IORESOURCE_MEM,
504 						       ICH_RES_MEM_GCS_PMC);
505 		p->gcs_pmc = devm_ioremap_resource(dev, p->gcs_pmc_res);
506 		if (IS_ERR(p->gcs_pmc))
507 			return PTR_ERR(p->gcs_pmc);
508 	}
509 
510 	/* Check chipset's NO_REBOOT bit */
511 	if (p->update_no_reboot_bit(p->no_reboot_priv, false) &&
512 	    iTCO_vendor_check_noreboot_on()) {
513 		pr_info("unable to reset NO_REBOOT flag, device disabled by hardware/BIOS\n");
514 		return -ENODEV;	/* Cannot reset NO_REBOOT bit */
515 	}
516 
517 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
518 	p->update_no_reboot_bit(p->no_reboot_priv, true);
519 
520 	if (turn_SMI_watchdog_clear_off >= p->iTCO_version) {
521 		/*
522 		 * Bit 13: TCO_EN -> 0
523 		 * Disables TCO logic generating an SMI#
524 		 */
525 		val32 = inl(SMI_EN(p));
526 		val32 &= 0xffffdfff;	/* Turn off SMI clearing watchdog */
527 		outl(val32, SMI_EN(p));
528 	}
529 
530 	if (!devm_request_region(dev, p->tco_res->start,
531 				 resource_size(p->tco_res),
532 				 pdev->name)) {
533 		pr_err("I/O address 0x%04llx already in use, device disabled\n",
534 		       (u64)TCOBASE(p));
535 		return -EBUSY;
536 	}
537 
538 	pr_info("Found a %s TCO device (Version=%d, TCOBASE=0x%04llx)\n",
539 		pdata->name, pdata->version, (u64)TCOBASE(p));
540 
541 	/* Clear out the (probably old) status */
542 	switch (p->iTCO_version) {
543 	case 6:
544 	case 5:
545 	case 4:
546 		outw(0x0008, TCO1_STS(p)); /* Clear the Time Out Status bit */
547 		outw(0x0002, TCO2_STS(p)); /* Clear SECOND_TO_STS bit */
548 		break;
549 	case 3:
550 		outl(0x20008, TCO1_STS(p));
551 		break;
552 	case 2:
553 	case 1:
554 	default:
555 		outw(0x0008, TCO1_STS(p)); /* Clear the Time Out Status bit */
556 		outw(0x0002, TCO2_STS(p)); /* Clear SECOND_TO_STS bit */
557 		outw(0x0004, TCO2_STS(p)); /* Clear BOOT_STS bit */
558 		break;
559 	}
560 
561 	p->wddev.info =	&ident,
562 	p->wddev.ops = &iTCO_wdt_ops,
563 	p->wddev.bootstatus = 0;
564 	p->wddev.timeout = WATCHDOG_TIMEOUT;
565 	watchdog_set_nowayout(&p->wddev, nowayout);
566 	p->wddev.parent = dev;
567 
568 	watchdog_set_drvdata(&p->wddev, p);
569 	platform_set_drvdata(pdev, p);
570 
571 	/* Make sure the watchdog is not running */
572 	iTCO_wdt_stop(&p->wddev);
573 
574 	/* Check that the heartbeat value is within it's range;
575 	   if not reset to the default */
576 	if (iTCO_wdt_set_timeout(&p->wddev, heartbeat)) {
577 		iTCO_wdt_set_timeout(&p->wddev, WATCHDOG_TIMEOUT);
578 		pr_info("timeout value out of range, using %d\n",
579 			WATCHDOG_TIMEOUT);
580 	}
581 
582 	watchdog_stop_on_reboot(&p->wddev);
583 	watchdog_stop_on_unregister(&p->wddev);
584 	ret = devm_watchdog_register_device(dev, &p->wddev);
585 	if (ret != 0) {
586 		pr_err("cannot register watchdog device (err=%d)\n", ret);
587 		return ret;
588 	}
589 
590 	pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
591 		heartbeat, nowayout);
592 
593 	return 0;
594 }
595 
596 #ifdef CONFIG_PM_SLEEP
597 /*
598  * Suspend-to-idle requires this, because it stops the ticks and timekeeping, so
599  * the watchdog cannot be pinged while in that state.  In ACPI sleep states the
600  * watchdog is stopped by the platform firmware.
601  */
602 
603 #ifdef CONFIG_ACPI
604 static inline bool need_suspend(void)
605 {
606 	return acpi_target_system_state() == ACPI_STATE_S0;
607 }
608 #else
609 static inline bool need_suspend(void) { return true; }
610 #endif
611 
612 static int iTCO_wdt_suspend_noirq(struct device *dev)
613 {
614 	struct iTCO_wdt_private *p = dev_get_drvdata(dev);
615 	int ret = 0;
616 
617 	p->suspended = false;
618 	if (watchdog_active(&p->wddev) && need_suspend()) {
619 		ret = iTCO_wdt_stop(&p->wddev);
620 		if (!ret)
621 			p->suspended = true;
622 	}
623 	return ret;
624 }
625 
626 static int iTCO_wdt_resume_noirq(struct device *dev)
627 {
628 	struct iTCO_wdt_private *p = dev_get_drvdata(dev);
629 
630 	if (p->suspended)
631 		iTCO_wdt_start(&p->wddev);
632 
633 	return 0;
634 }
635 
636 static const struct dev_pm_ops iTCO_wdt_pm = {
637 	.suspend_noirq = iTCO_wdt_suspend_noirq,
638 	.resume_noirq = iTCO_wdt_resume_noirq,
639 };
640 
641 #define ITCO_WDT_PM_OPS	(&iTCO_wdt_pm)
642 #else
643 #define ITCO_WDT_PM_OPS	NULL
644 #endif /* CONFIG_PM_SLEEP */
645 
646 static struct platform_driver iTCO_wdt_driver = {
647 	.probe          = iTCO_wdt_probe,
648 	.driver         = {
649 		.name   = DRV_NAME,
650 		.pm     = ITCO_WDT_PM_OPS,
651 	},
652 };
653 
654 static int __init iTCO_wdt_init_module(void)
655 {
656 	pr_info("Intel TCO WatchDog Timer Driver v%s\n", DRV_VERSION);
657 
658 	return platform_driver_register(&iTCO_wdt_driver);
659 }
660 
661 static void __exit iTCO_wdt_cleanup_module(void)
662 {
663 	platform_driver_unregister(&iTCO_wdt_driver);
664 	pr_info("Watchdog Module Unloaded\n");
665 }
666 
667 module_init(iTCO_wdt_init_module);
668 module_exit(iTCO_wdt_cleanup_module);
669 
670 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
671 MODULE_DESCRIPTION("Intel TCO WatchDog Timer Driver");
672 MODULE_VERSION(DRV_VERSION);
673 MODULE_LICENSE("GPL");
674 MODULE_ALIAS("platform:" DRV_NAME);
675