xref: /openbmc/linux/drivers/watchdog/iTCO_wdt.c (revision de6da33e)
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 /* Module and version information */
44 #define DRV_NAME	"iTCO_wdt"
45 #define DRV_VERSION	"1.11"
46 
47 /* Includes */
48 #include <linux/acpi.h>			/* For ACPI support */
49 #include <linux/bits.h>			/* For BIT() */
50 #include <linux/module.h>		/* For module specific items */
51 #include <linux/moduleparam.h>		/* For new moduleparam's */
52 #include <linux/types.h>		/* For standard types (like size_t) */
53 #include <linux/errno.h>		/* For the -ENODEV/... values */
54 #include <linux/kernel.h>		/* For printk/panic/... */
55 #include <linux/watchdog.h>		/* For the watchdog specific items */
56 #include <linux/init.h>			/* For __init/__exit/... */
57 #include <linux/fs.h>			/* For file operations */
58 #include <linux/platform_device.h>	/* For platform_driver framework */
59 #include <linux/pci.h>			/* For pci functions */
60 #include <linux/ioport.h>		/* For io-port access */
61 #include <linux/spinlock.h>		/* For spin_lock/spin_unlock/... */
62 #include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
63 #include <linux/io.h>			/* For inb/outb/... */
64 #include <linux/platform_data/itco_wdt.h>
65 #include <linux/mfd/intel_pmc_bxt.h>
66 
67 #include "iTCO_vendor.h"
68 
69 /* Address definitions for the TCO */
70 /* TCO base address */
71 #define TCOBASE(p)	((p)->tco_res->start)
72 /* SMI Control and Enable Register */
73 #define SMI_EN(p)	((p)->smi_res->start)
74 
75 #define TCO_RLD(p)	(TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */
76 #define TCOv1_TMR(p)	(TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/
77 #define TCO_DAT_IN(p)	(TCOBASE(p) + 0x02) /* TCO Data In Register	*/
78 #define TCO_DAT_OUT(p)	(TCOBASE(p) + 0x03) /* TCO Data Out Register	*/
79 #define TCO1_STS(p)	(TCOBASE(p) + 0x04) /* TCO1 Status Register	*/
80 #define TCO2_STS(p)	(TCOBASE(p) + 0x06) /* TCO2 Status Register	*/
81 #define TCO1_CNT(p)	(TCOBASE(p) + 0x08) /* TCO1 Control Register	*/
82 #define TCO2_CNT(p)	(TCOBASE(p) + 0x0a) /* TCO2 Control Register	*/
83 #define TCOv2_TMR(p)	(TCOBASE(p) + 0x12) /* TCOv2 Timer Initial Value*/
84 
85 /* internal variables */
86 struct iTCO_wdt_private {
87 	struct watchdog_device wddev;
88 
89 	/* TCO version/generation */
90 	unsigned int iTCO_version;
91 	struct resource *tco_res;
92 	struct resource *smi_res;
93 	/*
94 	 * NO_REBOOT flag is Memory-Mapped GCS register bit 5 (TCO version 2),
95 	 * or memory-mapped PMC register bit 4 (TCO version 3).
96 	 */
97 	unsigned long __iomem *gcs_pmc;
98 	/* the lock for io operations */
99 	spinlock_t io_lock;
100 	/* the PCI-device */
101 	struct pci_dev *pci_dev;
102 	/* whether or not the watchdog has been suspended */
103 	bool suspended;
104 	/* no reboot API private data */
105 	void *no_reboot_priv;
106 	/* no reboot update function pointer */
107 	int (*update_no_reboot_bit)(void *p, bool set);
108 };
109 
110 /* module parameters */
111 #define WATCHDOG_TIMEOUT 30	/* 30 sec default heartbeat */
112 static int heartbeat = WATCHDOG_TIMEOUT;  /* in seconds */
113 module_param(heartbeat, int, 0);
114 MODULE_PARM_DESC(heartbeat, "Watchdog timeout in seconds. "
115 	"5..76 (TCO v1) or 3..614 (TCO v2), default="
116 				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
117 
118 static bool nowayout = WATCHDOG_NOWAYOUT;
119 module_param(nowayout, bool, 0);
120 MODULE_PARM_DESC(nowayout,
121 	"Watchdog cannot be stopped once started (default="
122 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
123 
124 static int turn_SMI_watchdog_clear_off = 1;
125 module_param(turn_SMI_watchdog_clear_off, int, 0);
126 MODULE_PARM_DESC(turn_SMI_watchdog_clear_off,
127 	"Turn off SMI clearing watchdog (depends on TCO-version)(default=1)");
128 
129 /*
130  * Some TCO specific functions
131  */
132 
133 /*
134  * The iTCO v1 and v2's internal timer is stored as ticks which decrement
135  * every 0.6 seconds.  v3's internal timer is stored as seconds (some
136  * datasheets incorrectly state 0.6 seconds).
137  */
138 static inline unsigned int seconds_to_ticks(struct iTCO_wdt_private *p,
139 					    int secs)
140 {
141 	return p->iTCO_version == 3 ? secs : (secs * 10) / 6;
142 }
143 
144 static inline unsigned int ticks_to_seconds(struct iTCO_wdt_private *p,
145 					    int ticks)
146 {
147 	return p->iTCO_version == 3 ? ticks : (ticks * 6) / 10;
148 }
149 
150 static inline u32 no_reboot_bit(struct iTCO_wdt_private *p)
151 {
152 	u32 enable_bit;
153 
154 	switch (p->iTCO_version) {
155 	case 5:
156 	case 3:
157 		enable_bit = 0x00000010;
158 		break;
159 	case 2:
160 		enable_bit = 0x00000020;
161 		break;
162 	case 4:
163 	case 1:
164 	default:
165 		enable_bit = 0x00000002;
166 		break;
167 	}
168 
169 	return enable_bit;
170 }
171 
172 static int update_no_reboot_bit_def(void *priv, bool set)
173 {
174 	return 0;
175 }
176 
177 static int update_no_reboot_bit_pci(void *priv, bool set)
178 {
179 	struct iTCO_wdt_private *p = priv;
180 	u32 val32 = 0, newval32 = 0;
181 
182 	pci_read_config_dword(p->pci_dev, 0xd4, &val32);
183 	if (set)
184 		val32 |= no_reboot_bit(p);
185 	else
186 		val32 &= ~no_reboot_bit(p);
187 	pci_write_config_dword(p->pci_dev, 0xd4, val32);
188 	pci_read_config_dword(p->pci_dev, 0xd4, &newval32);
189 
190 	/* make sure the update is successful */
191 	if (val32 != newval32)
192 		return -EIO;
193 
194 	return 0;
195 }
196 
197 static int update_no_reboot_bit_mem(void *priv, bool set)
198 {
199 	struct iTCO_wdt_private *p = priv;
200 	u32 val32 = 0, newval32 = 0;
201 
202 	val32 = readl(p->gcs_pmc);
203 	if (set)
204 		val32 |= no_reboot_bit(p);
205 	else
206 		val32 &= ~no_reboot_bit(p);
207 	writel(val32, p->gcs_pmc);
208 	newval32 = readl(p->gcs_pmc);
209 
210 	/* make sure the update is successful */
211 	if (val32 != newval32)
212 		return -EIO;
213 
214 	return 0;
215 }
216 
217 static int update_no_reboot_bit_cnt(void *priv, bool set)
218 {
219 	struct iTCO_wdt_private *p = priv;
220 	u16 val, newval;
221 
222 	val = inw(TCO1_CNT(p));
223 	if (set)
224 		val |= BIT(0);
225 	else
226 		val &= ~BIT(0);
227 	outw(val, TCO1_CNT(p));
228 	newval = inw(TCO1_CNT(p));
229 
230 	/* make sure the update is successful */
231 	return val != newval ? -EIO : 0;
232 }
233 
234 static int update_no_reboot_bit_pmc(void *priv, bool set)
235 {
236 	struct intel_pmc_dev *pmc = priv;
237 	u32 bits = PMC_CFG_NO_REBOOT_EN;
238 	u32 value = set ? bits : 0;
239 
240 	return intel_pmc_gcr_update(pmc, PMC_GCR_PMC_CFG_REG, bits, value);
241 }
242 
243 static void iTCO_wdt_no_reboot_bit_setup(struct iTCO_wdt_private *p,
244 					 struct platform_device *pdev,
245 					 struct itco_wdt_platform_data *pdata)
246 {
247 	if (pdata->no_reboot_use_pmc) {
248 		struct intel_pmc_dev *pmc = dev_get_drvdata(pdev->dev.parent);
249 
250 		p->update_no_reboot_bit = update_no_reboot_bit_pmc;
251 		p->no_reboot_priv = pmc;
252 		return;
253 	}
254 
255 	if (p->iTCO_version >= 6)
256 		p->update_no_reboot_bit = update_no_reboot_bit_cnt;
257 	else if (p->iTCO_version >= 2)
258 		p->update_no_reboot_bit = update_no_reboot_bit_mem;
259 	else if (p->iTCO_version == 1)
260 		p->update_no_reboot_bit = update_no_reboot_bit_pci;
261 	else
262 		p->update_no_reboot_bit = update_no_reboot_bit_def;
263 
264 	p->no_reboot_priv = p;
265 }
266 
267 static int iTCO_wdt_start(struct watchdog_device *wd_dev)
268 {
269 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
270 	unsigned int val;
271 
272 	spin_lock(&p->io_lock);
273 
274 	iTCO_vendor_pre_start(p->smi_res, wd_dev->timeout);
275 
276 	/* disable chipset's NO_REBOOT bit */
277 	if (p->update_no_reboot_bit(p->no_reboot_priv, false)) {
278 		spin_unlock(&p->io_lock);
279 		dev_err(wd_dev->parent, "failed to reset NO_REBOOT flag, reboot disabled by hardware/BIOS\n");
280 		return -EIO;
281 	}
282 
283 	/* Force the timer to its reload value by writing to the TCO_RLD
284 	   register */
285 	if (p->iTCO_version >= 2)
286 		outw(0x01, TCO_RLD(p));
287 	else if (p->iTCO_version == 1)
288 		outb(0x01, TCO_RLD(p));
289 
290 	/* Bit 11: TCO Timer Halt -> 0 = The TCO timer is enabled to count */
291 	val = inw(TCO1_CNT(p));
292 	val &= 0xf7ff;
293 	outw(val, TCO1_CNT(p));
294 	val = inw(TCO1_CNT(p));
295 	spin_unlock(&p->io_lock);
296 
297 	if (val & 0x0800)
298 		return -1;
299 	return 0;
300 }
301 
302 static int iTCO_wdt_stop(struct watchdog_device *wd_dev)
303 {
304 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
305 	unsigned int val;
306 
307 	spin_lock(&p->io_lock);
308 
309 	iTCO_vendor_pre_stop(p->smi_res);
310 
311 	/* Bit 11: TCO Timer Halt -> 1 = The TCO timer is disabled */
312 	val = inw(TCO1_CNT(p));
313 	val |= 0x0800;
314 	outw(val, TCO1_CNT(p));
315 	val = inw(TCO1_CNT(p));
316 
317 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
318 	p->update_no_reboot_bit(p->no_reboot_priv, true);
319 
320 	spin_unlock(&p->io_lock);
321 
322 	if ((val & 0x0800) == 0)
323 		return -1;
324 	return 0;
325 }
326 
327 static int iTCO_wdt_ping(struct watchdog_device *wd_dev)
328 {
329 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
330 
331 	spin_lock(&p->io_lock);
332 
333 	/* Reload the timer by writing to the TCO Timer Counter register */
334 	if (p->iTCO_version >= 2) {
335 		outw(0x01, TCO_RLD(p));
336 	} else if (p->iTCO_version == 1) {
337 		/* Reset the timeout status bit so that the timer
338 		 * needs to count down twice again before rebooting */
339 		outw(0x0008, TCO1_STS(p));	/* write 1 to clear bit */
340 
341 		outb(0x01, TCO_RLD(p));
342 	}
343 
344 	spin_unlock(&p->io_lock);
345 	return 0;
346 }
347 
348 static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
349 {
350 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
351 	unsigned int val16;
352 	unsigned char val8;
353 	unsigned int tmrval;
354 
355 	tmrval = seconds_to_ticks(p, t);
356 
357 	/* For TCO v1 the timer counts down twice before rebooting */
358 	if (p->iTCO_version == 1)
359 		tmrval /= 2;
360 
361 	/* from the specs: */
362 	/* "Values of 0h-3h are ignored and should not be attempted" */
363 	if (tmrval < 0x04)
364 		return -EINVAL;
365 	if ((p->iTCO_version >= 2 && tmrval > 0x3ff) ||
366 	    (p->iTCO_version == 1 && tmrval > 0x03f))
367 		return -EINVAL;
368 
369 	/* Write new heartbeat to watchdog */
370 	if (p->iTCO_version >= 2) {
371 		spin_lock(&p->io_lock);
372 		val16 = inw(TCOv2_TMR(p));
373 		val16 &= 0xfc00;
374 		val16 |= tmrval;
375 		outw(val16, TCOv2_TMR(p));
376 		val16 = inw(TCOv2_TMR(p));
377 		spin_unlock(&p->io_lock);
378 
379 		if ((val16 & 0x3ff) != tmrval)
380 			return -EINVAL;
381 	} else if (p->iTCO_version == 1) {
382 		spin_lock(&p->io_lock);
383 		val8 = inb(TCOv1_TMR(p));
384 		val8 &= 0xc0;
385 		val8 |= (tmrval & 0xff);
386 		outb(val8, TCOv1_TMR(p));
387 		val8 = inb(TCOv1_TMR(p));
388 		spin_unlock(&p->io_lock);
389 
390 		if ((val8 & 0x3f) != tmrval)
391 			return -EINVAL;
392 	}
393 
394 	wd_dev->timeout = t;
395 	return 0;
396 }
397 
398 static unsigned int iTCO_wdt_get_timeleft(struct watchdog_device *wd_dev)
399 {
400 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
401 	unsigned int val16;
402 	unsigned char val8;
403 	unsigned int time_left = 0;
404 
405 	/* read the TCO Timer */
406 	if (p->iTCO_version >= 2) {
407 		spin_lock(&p->io_lock);
408 		val16 = inw(TCO_RLD(p));
409 		val16 &= 0x3ff;
410 		spin_unlock(&p->io_lock);
411 
412 		time_left = ticks_to_seconds(p, val16);
413 	} else if (p->iTCO_version == 1) {
414 		spin_lock(&p->io_lock);
415 		val8 = inb(TCO_RLD(p));
416 		val8 &= 0x3f;
417 		if (!(inw(TCO1_STS(p)) & 0x0008))
418 			val8 += (inb(TCOv1_TMR(p)) & 0x3f);
419 		spin_unlock(&p->io_lock);
420 
421 		time_left = ticks_to_seconds(p, val8);
422 	}
423 	return time_left;
424 }
425 
426 static void iTCO_wdt_set_running(struct iTCO_wdt_private *p)
427 {
428 	u16 val;
429 
430 	/* Bit 11: TCO Timer Halt -> 0 = The TCO timer is * enabled */
431 	val = inw(TCO1_CNT(p));
432 	if (!(val & BIT(11)))
433 		set_bit(WDOG_HW_RUNNING, &p->wddev.status);
434 }
435 
436 /*
437  *	Kernel Interfaces
438  */
439 
440 static const struct watchdog_info ident = {
441 	.options =		WDIOF_SETTIMEOUT |
442 				WDIOF_KEEPALIVEPING |
443 				WDIOF_MAGICCLOSE,
444 	.firmware_version =	0,
445 	.identity =		DRV_NAME,
446 };
447 
448 static const struct watchdog_ops iTCO_wdt_ops = {
449 	.owner =		THIS_MODULE,
450 	.start =		iTCO_wdt_start,
451 	.stop =			iTCO_wdt_stop,
452 	.ping =			iTCO_wdt_ping,
453 	.set_timeout =		iTCO_wdt_set_timeout,
454 	.get_timeleft =		iTCO_wdt_get_timeleft,
455 };
456 
457 /*
458  *	Init & exit routines
459  */
460 
461 static int iTCO_wdt_probe(struct platform_device *pdev)
462 {
463 	struct device *dev = &pdev->dev;
464 	struct itco_wdt_platform_data *pdata = dev_get_platdata(dev);
465 	struct iTCO_wdt_private *p;
466 	unsigned long val32;
467 	int ret;
468 
469 	if (!pdata)
470 		return -ENODEV;
471 
472 	p = devm_kzalloc(dev, sizeof(*p), GFP_KERNEL);
473 	if (!p)
474 		return -ENOMEM;
475 
476 	spin_lock_init(&p->io_lock);
477 
478 	p->tco_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_TCO);
479 	if (!p->tco_res)
480 		return -ENODEV;
481 
482 	p->iTCO_version = pdata->version;
483 	p->pci_dev = to_pci_dev(dev->parent);
484 
485 	p->smi_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_SMI);
486 	if (p->smi_res) {
487 		/* The TCO logic uses the TCO_EN bit in the SMI_EN register */
488 		if (!devm_request_region(dev, p->smi_res->start,
489 					 resource_size(p->smi_res),
490 					 pdev->name)) {
491 			dev_err(dev, "I/O address 0x%04llx already in use, device disabled\n",
492 			       (u64)SMI_EN(p));
493 			return -EBUSY;
494 		}
495 	} else if (iTCO_vendorsupport ||
496 		   turn_SMI_watchdog_clear_off >= p->iTCO_version) {
497 		dev_err(dev, "SMI I/O resource is missing\n");
498 		return -ENODEV;
499 	}
500 
501 	iTCO_wdt_no_reboot_bit_setup(p, pdev, pdata);
502 
503 	/*
504 	 * Get the Memory-Mapped GCS or PMC register, we need it for the
505 	 * NO_REBOOT flag (TCO v2 and v3).
506 	 */
507 	if (p->iTCO_version >= 2 && p->iTCO_version < 6 &&
508 	    !pdata->no_reboot_use_pmc) {
509 		p->gcs_pmc = devm_platform_ioremap_resource(pdev, ICH_RES_MEM_GCS_PMC);
510 		if (IS_ERR(p->gcs_pmc))
511 			return PTR_ERR(p->gcs_pmc);
512 	}
513 
514 	/* Check chipset's NO_REBOOT bit */
515 	if (p->update_no_reboot_bit(p->no_reboot_priv, false) &&
516 	    iTCO_vendor_check_noreboot_on()) {
517 		dev_info(dev, "unable to reset NO_REBOOT flag, device disabled by hardware/BIOS\n");
518 		return -ENODEV;	/* Cannot reset NO_REBOOT bit */
519 	}
520 
521 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
522 	p->update_no_reboot_bit(p->no_reboot_priv, true);
523 
524 	if (turn_SMI_watchdog_clear_off >= p->iTCO_version) {
525 		/*
526 		 * Bit 13: TCO_EN -> 0
527 		 * Disables TCO logic generating an SMI#
528 		 */
529 		val32 = inl(SMI_EN(p));
530 		val32 &= 0xffffdfff;	/* Turn off SMI clearing watchdog */
531 		outl(val32, SMI_EN(p));
532 	}
533 
534 	if (!devm_request_region(dev, p->tco_res->start,
535 				 resource_size(p->tco_res),
536 				 pdev->name)) {
537 		dev_err(dev, "I/O address 0x%04llx already in use, device disabled\n",
538 		       (u64)TCOBASE(p));
539 		return -EBUSY;
540 	}
541 
542 	dev_info(dev, "Found a %s TCO device (Version=%d, TCOBASE=0x%04llx)\n",
543 		pdata->name, pdata->version, (u64)TCOBASE(p));
544 
545 	/* Clear out the (probably old) status */
546 	switch (p->iTCO_version) {
547 	case 6:
548 	case 5:
549 	case 4:
550 		outw(0x0008, TCO1_STS(p)); /* Clear the Time Out Status bit */
551 		outw(0x0002, TCO2_STS(p)); /* Clear SECOND_TO_STS bit */
552 		break;
553 	case 3:
554 		outl(0x20008, TCO1_STS(p));
555 		break;
556 	case 2:
557 	case 1:
558 	default:
559 		outw(0x0008, TCO1_STS(p)); /* Clear the Time Out Status bit */
560 		outw(0x0002, TCO2_STS(p)); /* Clear SECOND_TO_STS bit */
561 		outw(0x0004, TCO2_STS(p)); /* Clear BOOT_STS bit */
562 		break;
563 	}
564 
565 	p->wddev.info = &ident,
566 	p->wddev.ops = &iTCO_wdt_ops,
567 	p->wddev.bootstatus = 0;
568 	p->wddev.timeout = WATCHDOG_TIMEOUT;
569 	watchdog_set_nowayout(&p->wddev, nowayout);
570 	p->wddev.parent = dev;
571 
572 	watchdog_set_drvdata(&p->wddev, p);
573 	platform_set_drvdata(pdev, p);
574 
575 	iTCO_wdt_set_running(p);
576 
577 	/* Check that the heartbeat value is within it's range;
578 	   if not reset to the default */
579 	if (iTCO_wdt_set_timeout(&p->wddev, heartbeat)) {
580 		iTCO_wdt_set_timeout(&p->wddev, WATCHDOG_TIMEOUT);
581 		dev_info(dev, "timeout value out of range, using %d\n",
582 			WATCHDOG_TIMEOUT);
583 	}
584 
585 	watchdog_stop_on_reboot(&p->wddev);
586 	watchdog_stop_on_unregister(&p->wddev);
587 	ret = devm_watchdog_register_device(dev, &p->wddev);
588 	if (ret != 0) {
589 		dev_err(dev, "cannot register watchdog device (err=%d)\n", ret);
590 		return ret;
591 	}
592 
593 	dev_info(dev, "initialized. heartbeat=%d sec (nowayout=%d)\n",
594 		heartbeat, nowayout);
595 
596 	return 0;
597 }
598 
599 #ifdef CONFIG_PM_SLEEP
600 /*
601  * Suspend-to-idle requires this, because it stops the ticks and timekeeping, so
602  * the watchdog cannot be pinged while in that state.  In ACPI sleep states the
603  * watchdog is stopped by the platform firmware.
604  */
605 
606 #ifdef CONFIG_ACPI
607 static inline bool need_suspend(void)
608 {
609 	return acpi_target_system_state() == ACPI_STATE_S0;
610 }
611 #else
612 static inline bool need_suspend(void) { return true; }
613 #endif
614 
615 static int iTCO_wdt_suspend_noirq(struct device *dev)
616 {
617 	struct iTCO_wdt_private *p = dev_get_drvdata(dev);
618 	int ret = 0;
619 
620 	p->suspended = false;
621 	if (watchdog_active(&p->wddev) && need_suspend()) {
622 		ret = iTCO_wdt_stop(&p->wddev);
623 		if (!ret)
624 			p->suspended = true;
625 	}
626 	return ret;
627 }
628 
629 static int iTCO_wdt_resume_noirq(struct device *dev)
630 {
631 	struct iTCO_wdt_private *p = dev_get_drvdata(dev);
632 
633 	if (p->suspended)
634 		iTCO_wdt_start(&p->wddev);
635 
636 	return 0;
637 }
638 
639 static const struct dev_pm_ops iTCO_wdt_pm = {
640 	.suspend_noirq = iTCO_wdt_suspend_noirq,
641 	.resume_noirq = iTCO_wdt_resume_noirq,
642 };
643 
644 #define ITCO_WDT_PM_OPS	(&iTCO_wdt_pm)
645 #else
646 #define ITCO_WDT_PM_OPS	NULL
647 #endif /* CONFIG_PM_SLEEP */
648 
649 static struct platform_driver iTCO_wdt_driver = {
650 	.probe          = iTCO_wdt_probe,
651 	.driver         = {
652 		.name   = DRV_NAME,
653 		.pm     = ITCO_WDT_PM_OPS,
654 	},
655 };
656 
657 module_platform_driver(iTCO_wdt_driver);
658 
659 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
660 MODULE_DESCRIPTION("Intel TCO WatchDog Timer Driver");
661 MODULE_VERSION(DRV_VERSION);
662 MODULE_LICENSE("GPL");
663 MODULE_ALIAS("platform:" DRV_NAME);
664