xref: /openbmc/linux/drivers/watchdog/iTCO_wdt.c (revision 0bc92e7f)
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 	struct resource *gcs_pmc_res;
98 	unsigned long __iomem *gcs_pmc;
99 	/* the lock for io operations */
100 	spinlock_t io_lock;
101 	/* the PCI-device */
102 	struct pci_dev *pci_dev;
103 	/* whether or not the watchdog has been suspended */
104 	bool suspended;
105 	/* no reboot API private data */
106 	void *no_reboot_priv;
107 	/* no reboot update function pointer */
108 	int (*update_no_reboot_bit)(void *p, bool set);
109 };
110 
111 /* module parameters */
112 #define WATCHDOG_TIMEOUT 30	/* 30 sec default heartbeat */
113 static int heartbeat = WATCHDOG_TIMEOUT;  /* in seconds */
114 module_param(heartbeat, int, 0);
115 MODULE_PARM_DESC(heartbeat, "Watchdog timeout in seconds. "
116 	"5..76 (TCO v1) or 3..614 (TCO v2), default="
117 				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
118 
119 static bool nowayout = WATCHDOG_NOWAYOUT;
120 module_param(nowayout, bool, 0);
121 MODULE_PARM_DESC(nowayout,
122 	"Watchdog cannot be stopped once started (default="
123 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
124 
125 static int turn_SMI_watchdog_clear_off = 1;
126 module_param(turn_SMI_watchdog_clear_off, int, 0);
127 MODULE_PARM_DESC(turn_SMI_watchdog_clear_off,
128 	"Turn off SMI clearing watchdog (depends on TCO-version)(default=1)");
129 
130 /*
131  * Some TCO specific functions
132  */
133 
134 /*
135  * The iTCO v1 and v2's internal timer is stored as ticks which decrement
136  * every 0.6 seconds.  v3's internal timer is stored as seconds (some
137  * datasheets incorrectly state 0.6 seconds).
138  */
139 static inline unsigned int seconds_to_ticks(struct iTCO_wdt_private *p,
140 					    int secs)
141 {
142 	return p->iTCO_version == 3 ? secs : (secs * 10) / 6;
143 }
144 
145 static inline unsigned int ticks_to_seconds(struct iTCO_wdt_private *p,
146 					    int ticks)
147 {
148 	return p->iTCO_version == 3 ? ticks : (ticks * 6) / 10;
149 }
150 
151 static inline u32 no_reboot_bit(struct iTCO_wdt_private *p)
152 {
153 	u32 enable_bit;
154 
155 	switch (p->iTCO_version) {
156 	case 5:
157 	case 3:
158 		enable_bit = 0x00000010;
159 		break;
160 	case 2:
161 		enable_bit = 0x00000020;
162 		break;
163 	case 4:
164 	case 1:
165 	default:
166 		enable_bit = 0x00000002;
167 		break;
168 	}
169 
170 	return enable_bit;
171 }
172 
173 static int update_no_reboot_bit_def(void *priv, bool set)
174 {
175 	return 0;
176 }
177 
178 static int update_no_reboot_bit_pci(void *priv, bool set)
179 {
180 	struct iTCO_wdt_private *p = priv;
181 	u32 val32 = 0, newval32 = 0;
182 
183 	pci_read_config_dword(p->pci_dev, 0xd4, &val32);
184 	if (set)
185 		val32 |= no_reboot_bit(p);
186 	else
187 		val32 &= ~no_reboot_bit(p);
188 	pci_write_config_dword(p->pci_dev, 0xd4, val32);
189 	pci_read_config_dword(p->pci_dev, 0xd4, &newval32);
190 
191 	/* make sure the update is successful */
192 	if (val32 != newval32)
193 		return -EIO;
194 
195 	return 0;
196 }
197 
198 static int update_no_reboot_bit_mem(void *priv, bool set)
199 {
200 	struct iTCO_wdt_private *p = priv;
201 	u32 val32 = 0, newval32 = 0;
202 
203 	val32 = readl(p->gcs_pmc);
204 	if (set)
205 		val32 |= no_reboot_bit(p);
206 	else
207 		val32 &= ~no_reboot_bit(p);
208 	writel(val32, p->gcs_pmc);
209 	newval32 = readl(p->gcs_pmc);
210 
211 	/* make sure the update is successful */
212 	if (val32 != newval32)
213 		return -EIO;
214 
215 	return 0;
216 }
217 
218 static int update_no_reboot_bit_cnt(void *priv, bool set)
219 {
220 	struct iTCO_wdt_private *p = priv;
221 	u16 val, newval;
222 
223 	val = inw(TCO1_CNT(p));
224 	if (set)
225 		val |= BIT(0);
226 	else
227 		val &= ~BIT(0);
228 	outw(val, TCO1_CNT(p));
229 	newval = inw(TCO1_CNT(p));
230 
231 	/* make sure the update is successful */
232 	return val != newval ? -EIO : 0;
233 }
234 
235 static int update_no_reboot_bit_pmc(void *priv, bool set)
236 {
237 	struct intel_pmc_dev *pmc = priv;
238 	u32 bits = PMC_CFG_NO_REBOOT_EN;
239 	u32 value = set ? bits : 0;
240 
241 	return intel_pmc_gcr_update(pmc, PMC_GCR_PMC_CFG_REG, bits, value);
242 }
243 
244 static void iTCO_wdt_no_reboot_bit_setup(struct iTCO_wdt_private *p,
245 					 struct platform_device *pdev,
246 					 struct itco_wdt_platform_data *pdata)
247 {
248 	if (pdata->no_reboot_use_pmc) {
249 		struct intel_pmc_dev *pmc = dev_get_drvdata(pdev->dev.parent);
250 
251 		p->update_no_reboot_bit = update_no_reboot_bit_pmc;
252 		p->no_reboot_priv = pmc;
253 		return;
254 	}
255 
256 	if (p->iTCO_version >= 6)
257 		p->update_no_reboot_bit = update_no_reboot_bit_cnt;
258 	else if (p->iTCO_version >= 2)
259 		p->update_no_reboot_bit = update_no_reboot_bit_mem;
260 	else if (p->iTCO_version == 1)
261 		p->update_no_reboot_bit = update_no_reboot_bit_pci;
262 	else
263 		p->update_no_reboot_bit = update_no_reboot_bit_def;
264 
265 	p->no_reboot_priv = p;
266 }
267 
268 static int iTCO_wdt_start(struct watchdog_device *wd_dev)
269 {
270 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
271 	unsigned int val;
272 
273 	spin_lock(&p->io_lock);
274 
275 	iTCO_vendor_pre_start(p->smi_res, wd_dev->timeout);
276 
277 	/* disable chipset's NO_REBOOT bit */
278 	if (p->update_no_reboot_bit(p->no_reboot_priv, false)) {
279 		spin_unlock(&p->io_lock);
280 		dev_err(wd_dev->parent, "failed to reset NO_REBOOT flag, reboot disabled by hardware/BIOS\n");
281 		return -EIO;
282 	}
283 
284 	/* Force the timer to its reload value by writing to the TCO_RLD
285 	   register */
286 	if (p->iTCO_version >= 2)
287 		outw(0x01, TCO_RLD(p));
288 	else if (p->iTCO_version == 1)
289 		outb(0x01, TCO_RLD(p));
290 
291 	/* Bit 11: TCO Timer Halt -> 0 = The TCO timer is enabled to count */
292 	val = inw(TCO1_CNT(p));
293 	val &= 0xf7ff;
294 	outw(val, TCO1_CNT(p));
295 	val = inw(TCO1_CNT(p));
296 	spin_unlock(&p->io_lock);
297 
298 	if (val & 0x0800)
299 		return -1;
300 	return 0;
301 }
302 
303 static int iTCO_wdt_stop(struct watchdog_device *wd_dev)
304 {
305 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
306 	unsigned int val;
307 
308 	spin_lock(&p->io_lock);
309 
310 	iTCO_vendor_pre_stop(p->smi_res);
311 
312 	/* Bit 11: TCO Timer Halt -> 1 = The TCO timer is disabled */
313 	val = inw(TCO1_CNT(p));
314 	val |= 0x0800;
315 	outw(val, TCO1_CNT(p));
316 	val = inw(TCO1_CNT(p));
317 
318 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
319 	p->update_no_reboot_bit(p->no_reboot_priv, true);
320 
321 	spin_unlock(&p->io_lock);
322 
323 	if ((val & 0x0800) == 0)
324 		return -1;
325 	return 0;
326 }
327 
328 static int iTCO_wdt_ping(struct watchdog_device *wd_dev)
329 {
330 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
331 
332 	spin_lock(&p->io_lock);
333 
334 	/* Reload the timer by writing to the TCO Timer Counter register */
335 	if (p->iTCO_version >= 2) {
336 		outw(0x01, TCO_RLD(p));
337 	} else if (p->iTCO_version == 1) {
338 		/* Reset the timeout status bit so that the timer
339 		 * needs to count down twice again before rebooting */
340 		outw(0x0008, TCO1_STS(p));	/* write 1 to clear bit */
341 
342 		outb(0x01, TCO_RLD(p));
343 	}
344 
345 	spin_unlock(&p->io_lock);
346 	return 0;
347 }
348 
349 static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
350 {
351 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
352 	unsigned int val16;
353 	unsigned char val8;
354 	unsigned int tmrval;
355 
356 	tmrval = seconds_to_ticks(p, t);
357 
358 	/* For TCO v1 the timer counts down twice before rebooting */
359 	if (p->iTCO_version == 1)
360 		tmrval /= 2;
361 
362 	/* from the specs: */
363 	/* "Values of 0h-3h are ignored and should not be attempted" */
364 	if (tmrval < 0x04)
365 		return -EINVAL;
366 	if ((p->iTCO_version >= 2 && tmrval > 0x3ff) ||
367 	    (p->iTCO_version == 1 && tmrval > 0x03f))
368 		return -EINVAL;
369 
370 	/* Write new heartbeat to watchdog */
371 	if (p->iTCO_version >= 2) {
372 		spin_lock(&p->io_lock);
373 		val16 = inw(TCOv2_TMR(p));
374 		val16 &= 0xfc00;
375 		val16 |= tmrval;
376 		outw(val16, TCOv2_TMR(p));
377 		val16 = inw(TCOv2_TMR(p));
378 		spin_unlock(&p->io_lock);
379 
380 		if ((val16 & 0x3ff) != tmrval)
381 			return -EINVAL;
382 	} else if (p->iTCO_version == 1) {
383 		spin_lock(&p->io_lock);
384 		val8 = inb(TCOv1_TMR(p));
385 		val8 &= 0xc0;
386 		val8 |= (tmrval & 0xff);
387 		outb(val8, TCOv1_TMR(p));
388 		val8 = inb(TCOv1_TMR(p));
389 		spin_unlock(&p->io_lock);
390 
391 		if ((val8 & 0x3f) != tmrval)
392 			return -EINVAL;
393 	}
394 
395 	wd_dev->timeout = t;
396 	return 0;
397 }
398 
399 static unsigned int iTCO_wdt_get_timeleft(struct watchdog_device *wd_dev)
400 {
401 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
402 	unsigned int val16;
403 	unsigned char val8;
404 	unsigned int time_left = 0;
405 
406 	/* read the TCO Timer */
407 	if (p->iTCO_version >= 2) {
408 		spin_lock(&p->io_lock);
409 		val16 = inw(TCO_RLD(p));
410 		val16 &= 0x3ff;
411 		spin_unlock(&p->io_lock);
412 
413 		time_left = ticks_to_seconds(p, val16);
414 	} else if (p->iTCO_version == 1) {
415 		spin_lock(&p->io_lock);
416 		val8 = inb(TCO_RLD(p));
417 		val8 &= 0x3f;
418 		if (!(inw(TCO1_STS(p)) & 0x0008))
419 			val8 += (inb(TCOv1_TMR(p)) & 0x3f);
420 		spin_unlock(&p->io_lock);
421 
422 		time_left = ticks_to_seconds(p, val8);
423 	}
424 	return time_left;
425 }
426 
427 /*
428  *	Kernel Interfaces
429  */
430 
431 static const struct watchdog_info ident = {
432 	.options =		WDIOF_SETTIMEOUT |
433 				WDIOF_KEEPALIVEPING |
434 				WDIOF_MAGICCLOSE,
435 	.firmware_version =	0,
436 	.identity =		DRV_NAME,
437 };
438 
439 static const struct watchdog_ops iTCO_wdt_ops = {
440 	.owner =		THIS_MODULE,
441 	.start =		iTCO_wdt_start,
442 	.stop =			iTCO_wdt_stop,
443 	.ping =			iTCO_wdt_ping,
444 	.set_timeout =		iTCO_wdt_set_timeout,
445 	.get_timeleft =		iTCO_wdt_get_timeleft,
446 };
447 
448 /*
449  *	Init & exit routines
450  */
451 
452 static int iTCO_wdt_probe(struct platform_device *pdev)
453 {
454 	struct device *dev = &pdev->dev;
455 	struct itco_wdt_platform_data *pdata = dev_get_platdata(dev);
456 	struct iTCO_wdt_private *p;
457 	unsigned long val32;
458 	int ret;
459 
460 	if (!pdata)
461 		return -ENODEV;
462 
463 	p = devm_kzalloc(dev, sizeof(*p), GFP_KERNEL);
464 	if (!p)
465 		return -ENOMEM;
466 
467 	spin_lock_init(&p->io_lock);
468 
469 	p->tco_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_TCO);
470 	if (!p->tco_res)
471 		return -ENODEV;
472 
473 	p->iTCO_version = pdata->version;
474 	p->pci_dev = to_pci_dev(dev->parent);
475 
476 	p->smi_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_SMI);
477 	if (p->smi_res) {
478 		/* The TCO logic uses the TCO_EN bit in the SMI_EN register */
479 		if (!devm_request_region(dev, p->smi_res->start,
480 					 resource_size(p->smi_res),
481 					 pdev->name)) {
482 			pr_err("I/O address 0x%04llx already in use, device disabled\n",
483 			       (u64)SMI_EN(p));
484 			return -EBUSY;
485 		}
486 	} else if (iTCO_vendorsupport ||
487 		   turn_SMI_watchdog_clear_off >= p->iTCO_version) {
488 		pr_err("SMI I/O resource is missing\n");
489 		return -ENODEV;
490 	}
491 
492 	iTCO_wdt_no_reboot_bit_setup(p, pdev, pdata);
493 
494 	/*
495 	 * Get the Memory-Mapped GCS or PMC register, we need it for the
496 	 * NO_REBOOT flag (TCO v2 and v3).
497 	 */
498 	if (p->iTCO_version >= 2 && p->iTCO_version < 6 &&
499 	    !pdata->no_reboot_use_pmc) {
500 		p->gcs_pmc_res = platform_get_resource(pdev,
501 						       IORESOURCE_MEM,
502 						       ICH_RES_MEM_GCS_PMC);
503 		p->gcs_pmc = devm_ioremap_resource(dev, p->gcs_pmc_res);
504 		if (IS_ERR(p->gcs_pmc))
505 			return PTR_ERR(p->gcs_pmc);
506 	}
507 
508 	/* Check chipset's NO_REBOOT bit */
509 	if (p->update_no_reboot_bit(p->no_reboot_priv, false) &&
510 	    iTCO_vendor_check_noreboot_on()) {
511 		dev_info(dev, "unable to reset NO_REBOOT flag, device disabled by hardware/BIOS\n");
512 		return -ENODEV;	/* Cannot reset NO_REBOOT bit */
513 	}
514 
515 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
516 	p->update_no_reboot_bit(p->no_reboot_priv, true);
517 
518 	if (turn_SMI_watchdog_clear_off >= p->iTCO_version) {
519 		/*
520 		 * Bit 13: TCO_EN -> 0
521 		 * Disables TCO logic generating an SMI#
522 		 */
523 		val32 = inl(SMI_EN(p));
524 		val32 &= 0xffffdfff;	/* Turn off SMI clearing watchdog */
525 		outl(val32, SMI_EN(p));
526 	}
527 
528 	if (!devm_request_region(dev, p->tco_res->start,
529 				 resource_size(p->tco_res),
530 				 pdev->name)) {
531 		dev_err(dev, "I/O address 0x%04llx already in use, device disabled\n",
532 		       (u64)TCOBASE(p));
533 		return -EBUSY;
534 	}
535 
536 	dev_info(dev, "Found a %s TCO device (Version=%d, TCOBASE=0x%04llx)\n",
537 		pdata->name, pdata->version, (u64)TCOBASE(p));
538 
539 	/* Clear out the (probably old) status */
540 	switch (p->iTCO_version) {
541 	case 6:
542 	case 5:
543 	case 4:
544 		outw(0x0008, TCO1_STS(p)); /* Clear the Time Out Status bit */
545 		outw(0x0002, TCO2_STS(p)); /* Clear SECOND_TO_STS bit */
546 		break;
547 	case 3:
548 		outl(0x20008, TCO1_STS(p));
549 		break;
550 	case 2:
551 	case 1:
552 	default:
553 		outw(0x0008, TCO1_STS(p)); /* Clear the Time Out Status bit */
554 		outw(0x0002, TCO2_STS(p)); /* Clear SECOND_TO_STS bit */
555 		outw(0x0004, TCO2_STS(p)); /* Clear BOOT_STS bit */
556 		break;
557 	}
558 
559 	p->wddev.info = &ident,
560 	p->wddev.ops = &iTCO_wdt_ops,
561 	p->wddev.bootstatus = 0;
562 	p->wddev.timeout = WATCHDOG_TIMEOUT;
563 	watchdog_set_nowayout(&p->wddev, nowayout);
564 	p->wddev.parent = dev;
565 
566 	watchdog_set_drvdata(&p->wddev, p);
567 	platform_set_drvdata(pdev, p);
568 
569 	/* Make sure the watchdog is not running */
570 	iTCO_wdt_stop(&p->wddev);
571 
572 	/* Check that the heartbeat value is within it's range;
573 	   if not reset to the default */
574 	if (iTCO_wdt_set_timeout(&p->wddev, heartbeat)) {
575 		iTCO_wdt_set_timeout(&p->wddev, WATCHDOG_TIMEOUT);
576 		dev_info(dev, "timeout value out of range, using %d\n",
577 			WATCHDOG_TIMEOUT);
578 	}
579 
580 	watchdog_stop_on_reboot(&p->wddev);
581 	watchdog_stop_on_unregister(&p->wddev);
582 	ret = devm_watchdog_register_device(dev, &p->wddev);
583 	if (ret != 0) {
584 		dev_err(dev, "cannot register watchdog device (err=%d)\n", ret);
585 		return ret;
586 	}
587 
588 	dev_info(dev, "initialized. heartbeat=%d sec (nowayout=%d)\n",
589 		heartbeat, nowayout);
590 
591 	return 0;
592 }
593 
594 #ifdef CONFIG_PM_SLEEP
595 /*
596  * Suspend-to-idle requires this, because it stops the ticks and timekeeping, so
597  * the watchdog cannot be pinged while in that state.  In ACPI sleep states the
598  * watchdog is stopped by the platform firmware.
599  */
600 
601 #ifdef CONFIG_ACPI
602 static inline bool need_suspend(void)
603 {
604 	return acpi_target_system_state() == ACPI_STATE_S0;
605 }
606 #else
607 static inline bool need_suspend(void) { return true; }
608 #endif
609 
610 static int iTCO_wdt_suspend_noirq(struct device *dev)
611 {
612 	struct iTCO_wdt_private *p = dev_get_drvdata(dev);
613 	int ret = 0;
614 
615 	p->suspended = false;
616 	if (watchdog_active(&p->wddev) && need_suspend()) {
617 		ret = iTCO_wdt_stop(&p->wddev);
618 		if (!ret)
619 			p->suspended = true;
620 	}
621 	return ret;
622 }
623 
624 static int iTCO_wdt_resume_noirq(struct device *dev)
625 {
626 	struct iTCO_wdt_private *p = dev_get_drvdata(dev);
627 
628 	if (p->suspended)
629 		iTCO_wdt_start(&p->wddev);
630 
631 	return 0;
632 }
633 
634 static const struct dev_pm_ops iTCO_wdt_pm = {
635 	.suspend_noirq = iTCO_wdt_suspend_noirq,
636 	.resume_noirq = iTCO_wdt_resume_noirq,
637 };
638 
639 #define ITCO_WDT_PM_OPS	(&iTCO_wdt_pm)
640 #else
641 #define ITCO_WDT_PM_OPS	NULL
642 #endif /* CONFIG_PM_SLEEP */
643 
644 static struct platform_driver iTCO_wdt_driver = {
645 	.probe          = iTCO_wdt_probe,
646 	.driver         = {
647 		.name   = DRV_NAME,
648 		.pm     = ITCO_WDT_PM_OPS,
649 	},
650 };
651 
652 module_platform_driver(iTCO_wdt_driver);
653 
654 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
655 MODULE_DESCRIPTION("Intel TCO WatchDog Timer Driver");
656 MODULE_VERSION(DRV_VERSION);
657 MODULE_LICENSE("GPL");
658 MODULE_ALIAS("platform:" DRV_NAME);
659