xref: /linux/drivers/watchdog/iTCO_wdt.c (revision 37744feebc086908fd89760650f458ab19071750)
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 
68 #include "iTCO_vendor.h"
69 
70 /* Address definitions for the TCO */
71 /* TCO base address */
72 #define TCOBASE(p)	((p)->tco_res->start)
73 /* SMI Control and Enable Register */
74 #define SMI_EN(p)	((p)->smi_res->start)
75 
76 #define TCO_RLD(p)	(TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */
77 #define TCOv1_TMR(p)	(TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/
78 #define TCO_DAT_IN(p)	(TCOBASE(p) + 0x02) /* TCO Data In Register	*/
79 #define TCO_DAT_OUT(p)	(TCOBASE(p) + 0x03) /* TCO Data Out Register	*/
80 #define TCO1_STS(p)	(TCOBASE(p) + 0x04) /* TCO1 Status Register	*/
81 #define TCO2_STS(p)	(TCOBASE(p) + 0x06) /* TCO2 Status Register	*/
82 #define TCO1_CNT(p)	(TCOBASE(p) + 0x08) /* TCO1 Control Register	*/
83 #define TCO2_CNT(p)	(TCOBASE(p) + 0x0a) /* TCO2 Control Register	*/
84 #define TCOv2_TMR(p)	(TCOBASE(p) + 0x12) /* TCOv2 Timer Initial Value*/
85 
86 /* internal variables */
87 struct iTCO_wdt_private {
88 	struct watchdog_device wddev;
89 
90 	/* TCO version/generation */
91 	unsigned int iTCO_version;
92 	struct resource *tco_res;
93 	struct resource *smi_res;
94 	/*
95 	 * NO_REBOOT flag is Memory-Mapped GCS register bit 5 (TCO version 2),
96 	 * or memory-mapped PMC register bit 4 (TCO version 3).
97 	 */
98 	struct resource *gcs_pmc_res;
99 	unsigned long __iomem *gcs_pmc;
100 	/* the lock for io operations */
101 	spinlock_t io_lock;
102 	/* the PCI-device */
103 	struct pci_dev *pci_dev;
104 	/* whether or not the watchdog has been suspended */
105 	bool suspended;
106 	/* no reboot API private data */
107 	void *no_reboot_priv;
108 	/* no reboot update function pointer */
109 	int (*update_no_reboot_bit)(void *p, bool set);
110 };
111 
112 /* module parameters */
113 #define WATCHDOG_TIMEOUT 30	/* 30 sec default heartbeat */
114 static int heartbeat = WATCHDOG_TIMEOUT;  /* in seconds */
115 module_param(heartbeat, int, 0);
116 MODULE_PARM_DESC(heartbeat, "Watchdog timeout in seconds. "
117 	"5..76 (TCO v1) or 3..614 (TCO v2), default="
118 				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
119 
120 static bool nowayout = WATCHDOG_NOWAYOUT;
121 module_param(nowayout, bool, 0);
122 MODULE_PARM_DESC(nowayout,
123 	"Watchdog cannot be stopped once started (default="
124 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
125 
126 static int turn_SMI_watchdog_clear_off = 1;
127 module_param(turn_SMI_watchdog_clear_off, int, 0);
128 MODULE_PARM_DESC(turn_SMI_watchdog_clear_off,
129 	"Turn off SMI clearing watchdog (depends on TCO-version)(default=1)");
130 
131 /*
132  * Some TCO specific functions
133  */
134 
135 /*
136  * The iTCO v1 and v2's internal timer is stored as ticks which decrement
137  * every 0.6 seconds.  v3's internal timer is stored as seconds (some
138  * datasheets incorrectly state 0.6 seconds).
139  */
140 static inline unsigned int seconds_to_ticks(struct iTCO_wdt_private *p,
141 					    int secs)
142 {
143 	return p->iTCO_version == 3 ? secs : (secs * 10) / 6;
144 }
145 
146 static inline unsigned int ticks_to_seconds(struct iTCO_wdt_private *p,
147 					    int ticks)
148 {
149 	return p->iTCO_version == 3 ? ticks : (ticks * 6) / 10;
150 }
151 
152 static inline u32 no_reboot_bit(struct iTCO_wdt_private *p)
153 {
154 	u32 enable_bit;
155 
156 	switch (p->iTCO_version) {
157 	case 5:
158 	case 3:
159 		enable_bit = 0x00000010;
160 		break;
161 	case 2:
162 		enable_bit = 0x00000020;
163 		break;
164 	case 4:
165 	case 1:
166 	default:
167 		enable_bit = 0x00000002;
168 		break;
169 	}
170 
171 	return enable_bit;
172 }
173 
174 static int update_no_reboot_bit_def(void *priv, bool set)
175 {
176 	return 0;
177 }
178 
179 static int update_no_reboot_bit_pci(void *priv, bool set)
180 {
181 	struct iTCO_wdt_private *p = priv;
182 	u32 val32 = 0, newval32 = 0;
183 
184 	pci_read_config_dword(p->pci_dev, 0xd4, &val32);
185 	if (set)
186 		val32 |= no_reboot_bit(p);
187 	else
188 		val32 &= ~no_reboot_bit(p);
189 	pci_write_config_dword(p->pci_dev, 0xd4, val32);
190 	pci_read_config_dword(p->pci_dev, 0xd4, &newval32);
191 
192 	/* make sure the update is successful */
193 	if (val32 != newval32)
194 		return -EIO;
195 
196 	return 0;
197 }
198 
199 static int update_no_reboot_bit_mem(void *priv, bool set)
200 {
201 	struct iTCO_wdt_private *p = priv;
202 	u32 val32 = 0, newval32 = 0;
203 
204 	val32 = readl(p->gcs_pmc);
205 	if (set)
206 		val32 |= no_reboot_bit(p);
207 	else
208 		val32 &= ~no_reboot_bit(p);
209 	writel(val32, p->gcs_pmc);
210 	newval32 = readl(p->gcs_pmc);
211 
212 	/* make sure the update is successful */
213 	if (val32 != newval32)
214 		return -EIO;
215 
216 	return 0;
217 }
218 
219 static int update_no_reboot_bit_cnt(void *priv, bool set)
220 {
221 	struct iTCO_wdt_private *p = priv;
222 	u16 val, newval;
223 
224 	val = inw(TCO1_CNT(p));
225 	if (set)
226 		val |= BIT(0);
227 	else
228 		val &= ~BIT(0);
229 	outw(val, TCO1_CNT(p));
230 	newval = inw(TCO1_CNT(p));
231 
232 	/* make sure the update is successful */
233 	return val != newval ? -EIO : 0;
234 }
235 
236 static void iTCO_wdt_no_reboot_bit_setup(struct iTCO_wdt_private *p,
237 		struct itco_wdt_platform_data *pdata)
238 {
239 	if (pdata->update_no_reboot_bit) {
240 		p->update_no_reboot_bit = pdata->update_no_reboot_bit;
241 		p->no_reboot_priv = pdata->no_reboot_priv;
242 		return;
243 	}
244 
245 	if (p->iTCO_version >= 6)
246 		p->update_no_reboot_bit = update_no_reboot_bit_cnt;
247 	else if (p->iTCO_version >= 2)
248 		p->update_no_reboot_bit = update_no_reboot_bit_mem;
249 	else if (p->iTCO_version == 1)
250 		p->update_no_reboot_bit = update_no_reboot_bit_pci;
251 	else
252 		p->update_no_reboot_bit = update_no_reboot_bit_def;
253 
254 	p->no_reboot_priv = p;
255 }
256 
257 static int iTCO_wdt_start(struct watchdog_device *wd_dev)
258 {
259 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
260 	unsigned int val;
261 
262 	spin_lock(&p->io_lock);
263 
264 	iTCO_vendor_pre_start(p->smi_res, wd_dev->timeout);
265 
266 	/* disable chipset's NO_REBOOT bit */
267 	if (p->update_no_reboot_bit(p->no_reboot_priv, false)) {
268 		spin_unlock(&p->io_lock);
269 		pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware/BIOS\n");
270 		return -EIO;
271 	}
272 
273 	/* Force the timer to its reload value by writing to the TCO_RLD
274 	   register */
275 	if (p->iTCO_version >= 2)
276 		outw(0x01, TCO_RLD(p));
277 	else if (p->iTCO_version == 1)
278 		outb(0x01, TCO_RLD(p));
279 
280 	/* Bit 11: TCO Timer Halt -> 0 = The TCO timer is enabled to count */
281 	val = inw(TCO1_CNT(p));
282 	val &= 0xf7ff;
283 	outw(val, TCO1_CNT(p));
284 	val = inw(TCO1_CNT(p));
285 	spin_unlock(&p->io_lock);
286 
287 	if (val & 0x0800)
288 		return -1;
289 	return 0;
290 }
291 
292 static int iTCO_wdt_stop(struct watchdog_device *wd_dev)
293 {
294 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
295 	unsigned int val;
296 
297 	spin_lock(&p->io_lock);
298 
299 	iTCO_vendor_pre_stop(p->smi_res);
300 
301 	/* Bit 11: TCO Timer Halt -> 1 = The TCO timer is disabled */
302 	val = inw(TCO1_CNT(p));
303 	val |= 0x0800;
304 	outw(val, TCO1_CNT(p));
305 	val = inw(TCO1_CNT(p));
306 
307 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
308 	p->update_no_reboot_bit(p->no_reboot_priv, true);
309 
310 	spin_unlock(&p->io_lock);
311 
312 	if ((val & 0x0800) == 0)
313 		return -1;
314 	return 0;
315 }
316 
317 static int iTCO_wdt_ping(struct watchdog_device *wd_dev)
318 {
319 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
320 
321 	spin_lock(&p->io_lock);
322 
323 	/* Reload the timer by writing to the TCO Timer Counter register */
324 	if (p->iTCO_version >= 2) {
325 		outw(0x01, TCO_RLD(p));
326 	} else if (p->iTCO_version == 1) {
327 		/* Reset the timeout status bit so that the timer
328 		 * needs to count down twice again before rebooting */
329 		outw(0x0008, TCO1_STS(p));	/* write 1 to clear bit */
330 
331 		outb(0x01, TCO_RLD(p));
332 	}
333 
334 	spin_unlock(&p->io_lock);
335 	return 0;
336 }
337 
338 static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
339 {
340 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
341 	unsigned int val16;
342 	unsigned char val8;
343 	unsigned int tmrval;
344 
345 	tmrval = seconds_to_ticks(p, t);
346 
347 	/* For TCO v1 the timer counts down twice before rebooting */
348 	if (p->iTCO_version == 1)
349 		tmrval /= 2;
350 
351 	/* from the specs: */
352 	/* "Values of 0h-3h are ignored and should not be attempted" */
353 	if (tmrval < 0x04)
354 		return -EINVAL;
355 	if ((p->iTCO_version >= 2 && tmrval > 0x3ff) ||
356 	    (p->iTCO_version == 1 && tmrval > 0x03f))
357 		return -EINVAL;
358 
359 	/* Write new heartbeat to watchdog */
360 	if (p->iTCO_version >= 2) {
361 		spin_lock(&p->io_lock);
362 		val16 = inw(TCOv2_TMR(p));
363 		val16 &= 0xfc00;
364 		val16 |= tmrval;
365 		outw(val16, TCOv2_TMR(p));
366 		val16 = inw(TCOv2_TMR(p));
367 		spin_unlock(&p->io_lock);
368 
369 		if ((val16 & 0x3ff) != tmrval)
370 			return -EINVAL;
371 	} else if (p->iTCO_version == 1) {
372 		spin_lock(&p->io_lock);
373 		val8 = inb(TCOv1_TMR(p));
374 		val8 &= 0xc0;
375 		val8 |= (tmrval & 0xff);
376 		outb(val8, TCOv1_TMR(p));
377 		val8 = inb(TCOv1_TMR(p));
378 		spin_unlock(&p->io_lock);
379 
380 		if ((val8 & 0x3f) != tmrval)
381 			return -EINVAL;
382 	}
383 
384 	wd_dev->timeout = t;
385 	return 0;
386 }
387 
388 static unsigned int iTCO_wdt_get_timeleft(struct watchdog_device *wd_dev)
389 {
390 	struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
391 	unsigned int val16;
392 	unsigned char val8;
393 	unsigned int time_left = 0;
394 
395 	/* read the TCO Timer */
396 	if (p->iTCO_version >= 2) {
397 		spin_lock(&p->io_lock);
398 		val16 = inw(TCO_RLD(p));
399 		val16 &= 0x3ff;
400 		spin_unlock(&p->io_lock);
401 
402 		time_left = ticks_to_seconds(p, val16);
403 	} else if (p->iTCO_version == 1) {
404 		spin_lock(&p->io_lock);
405 		val8 = inb(TCO_RLD(p));
406 		val8 &= 0x3f;
407 		if (!(inw(TCO1_STS(p)) & 0x0008))
408 			val8 += (inb(TCOv1_TMR(p)) & 0x3f);
409 		spin_unlock(&p->io_lock);
410 
411 		time_left = ticks_to_seconds(p, val8);
412 	}
413 	return time_left;
414 }
415 
416 /*
417  *	Kernel Interfaces
418  */
419 
420 static const struct watchdog_info ident = {
421 	.options =		WDIOF_SETTIMEOUT |
422 				WDIOF_KEEPALIVEPING |
423 				WDIOF_MAGICCLOSE,
424 	.firmware_version =	0,
425 	.identity =		DRV_NAME,
426 };
427 
428 static const struct watchdog_ops iTCO_wdt_ops = {
429 	.owner =		THIS_MODULE,
430 	.start =		iTCO_wdt_start,
431 	.stop =			iTCO_wdt_stop,
432 	.ping =			iTCO_wdt_ping,
433 	.set_timeout =		iTCO_wdt_set_timeout,
434 	.get_timeleft =		iTCO_wdt_get_timeleft,
435 };
436 
437 /*
438  *	Init & exit routines
439  */
440 
441 static int iTCO_wdt_probe(struct platform_device *pdev)
442 {
443 	struct device *dev = &pdev->dev;
444 	struct itco_wdt_platform_data *pdata = dev_get_platdata(dev);
445 	struct iTCO_wdt_private *p;
446 	unsigned long val32;
447 	int ret;
448 
449 	if (!pdata)
450 		return -ENODEV;
451 
452 	p = devm_kzalloc(dev, sizeof(*p), GFP_KERNEL);
453 	if (!p)
454 		return -ENOMEM;
455 
456 	spin_lock_init(&p->io_lock);
457 
458 	p->tco_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_TCO);
459 	if (!p->tco_res)
460 		return -ENODEV;
461 
462 	p->iTCO_version = pdata->version;
463 	p->pci_dev = to_pci_dev(dev->parent);
464 
465 	p->smi_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_SMI);
466 	if (p->smi_res) {
467 		/* The TCO logic uses the TCO_EN bit in the SMI_EN register */
468 		if (!devm_request_region(dev, p->smi_res->start,
469 					 resource_size(p->smi_res),
470 					 pdev->name)) {
471 			pr_err("I/O address 0x%04llx already in use, device disabled\n",
472 			       (u64)SMI_EN(p));
473 			return -EBUSY;
474 		}
475 	} else if (iTCO_vendorsupport ||
476 		   turn_SMI_watchdog_clear_off >= p->iTCO_version) {
477 		pr_err("SMI I/O resource is missing\n");
478 		return -ENODEV;
479 	}
480 
481 	iTCO_wdt_no_reboot_bit_setup(p, pdata);
482 
483 	/*
484 	 * Get the Memory-Mapped GCS or PMC register, we need it for the
485 	 * NO_REBOOT flag (TCO v2 and v3).
486 	 */
487 	if (p->iTCO_version >= 2 && p->iTCO_version < 6 &&
488 	    !pdata->update_no_reboot_bit) {
489 		p->gcs_pmc_res = platform_get_resource(pdev,
490 						       IORESOURCE_MEM,
491 						       ICH_RES_MEM_GCS_PMC);
492 		p->gcs_pmc = devm_ioremap_resource(dev, p->gcs_pmc_res);
493 		if (IS_ERR(p->gcs_pmc))
494 			return PTR_ERR(p->gcs_pmc);
495 	}
496 
497 	/* Check chipset's NO_REBOOT bit */
498 	if (p->update_no_reboot_bit(p->no_reboot_priv, false) &&
499 	    iTCO_vendor_check_noreboot_on()) {
500 		pr_info("unable to reset NO_REBOOT flag, device disabled by hardware/BIOS\n");
501 		return -ENODEV;	/* Cannot reset NO_REBOOT bit */
502 	}
503 
504 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
505 	p->update_no_reboot_bit(p->no_reboot_priv, true);
506 
507 	if (turn_SMI_watchdog_clear_off >= p->iTCO_version) {
508 		/*
509 		 * Bit 13: TCO_EN -> 0
510 		 * Disables TCO logic generating an SMI#
511 		 */
512 		val32 = inl(SMI_EN(p));
513 		val32 &= 0xffffdfff;	/* Turn off SMI clearing watchdog */
514 		outl(val32, SMI_EN(p));
515 	}
516 
517 	if (!devm_request_region(dev, p->tco_res->start,
518 				 resource_size(p->tco_res),
519 				 pdev->name)) {
520 		pr_err("I/O address 0x%04llx already in use, device disabled\n",
521 		       (u64)TCOBASE(p));
522 		return -EBUSY;
523 	}
524 
525 	pr_info("Found a %s TCO device (Version=%d, TCOBASE=0x%04llx)\n",
526 		pdata->name, pdata->version, (u64)TCOBASE(p));
527 
528 	/* Clear out the (probably old) status */
529 	switch (p->iTCO_version) {
530 	case 6:
531 	case 5:
532 	case 4:
533 		outw(0x0008, TCO1_STS(p)); /* Clear the Time Out Status bit */
534 		outw(0x0002, TCO2_STS(p)); /* Clear SECOND_TO_STS bit */
535 		break;
536 	case 3:
537 		outl(0x20008, TCO1_STS(p));
538 		break;
539 	case 2:
540 	case 1:
541 	default:
542 		outw(0x0008, TCO1_STS(p)); /* Clear the Time Out Status bit */
543 		outw(0x0002, TCO2_STS(p)); /* Clear SECOND_TO_STS bit */
544 		outw(0x0004, TCO2_STS(p)); /* Clear BOOT_STS bit */
545 		break;
546 	}
547 
548 	p->wddev.info =	&ident,
549 	p->wddev.ops = &iTCO_wdt_ops,
550 	p->wddev.bootstatus = 0;
551 	p->wddev.timeout = WATCHDOG_TIMEOUT;
552 	watchdog_set_nowayout(&p->wddev, nowayout);
553 	p->wddev.parent = dev;
554 
555 	watchdog_set_drvdata(&p->wddev, p);
556 	platform_set_drvdata(pdev, p);
557 
558 	/* Make sure the watchdog is not running */
559 	iTCO_wdt_stop(&p->wddev);
560 
561 	/* Check that the heartbeat value is within it's range;
562 	   if not reset to the default */
563 	if (iTCO_wdt_set_timeout(&p->wddev, heartbeat)) {
564 		iTCO_wdt_set_timeout(&p->wddev, WATCHDOG_TIMEOUT);
565 		pr_info("timeout value out of range, using %d\n",
566 			WATCHDOG_TIMEOUT);
567 	}
568 
569 	watchdog_stop_on_reboot(&p->wddev);
570 	watchdog_stop_on_unregister(&p->wddev);
571 	ret = devm_watchdog_register_device(dev, &p->wddev);
572 	if (ret != 0) {
573 		pr_err("cannot register watchdog device (err=%d)\n", ret);
574 		return ret;
575 	}
576 
577 	pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
578 		heartbeat, nowayout);
579 
580 	return 0;
581 }
582 
583 #ifdef CONFIG_PM_SLEEP
584 /*
585  * Suspend-to-idle requires this, because it stops the ticks and timekeeping, so
586  * the watchdog cannot be pinged while in that state.  In ACPI sleep states the
587  * watchdog is stopped by the platform firmware.
588  */
589 
590 #ifdef CONFIG_ACPI
591 static inline bool need_suspend(void)
592 {
593 	return acpi_target_system_state() == ACPI_STATE_S0;
594 }
595 #else
596 static inline bool need_suspend(void) { return true; }
597 #endif
598 
599 static int iTCO_wdt_suspend_noirq(struct device *dev)
600 {
601 	struct iTCO_wdt_private *p = dev_get_drvdata(dev);
602 	int ret = 0;
603 
604 	p->suspended = false;
605 	if (watchdog_active(&p->wddev) && need_suspend()) {
606 		ret = iTCO_wdt_stop(&p->wddev);
607 		if (!ret)
608 			p->suspended = true;
609 	}
610 	return ret;
611 }
612 
613 static int iTCO_wdt_resume_noirq(struct device *dev)
614 {
615 	struct iTCO_wdt_private *p = dev_get_drvdata(dev);
616 
617 	if (p->suspended)
618 		iTCO_wdt_start(&p->wddev);
619 
620 	return 0;
621 }
622 
623 static const struct dev_pm_ops iTCO_wdt_pm = {
624 	.suspend_noirq = iTCO_wdt_suspend_noirq,
625 	.resume_noirq = iTCO_wdt_resume_noirq,
626 };
627 
628 #define ITCO_WDT_PM_OPS	(&iTCO_wdt_pm)
629 #else
630 #define ITCO_WDT_PM_OPS	NULL
631 #endif /* CONFIG_PM_SLEEP */
632 
633 static struct platform_driver iTCO_wdt_driver = {
634 	.probe          = iTCO_wdt_probe,
635 	.driver         = {
636 		.name   = DRV_NAME,
637 		.pm     = ITCO_WDT_PM_OPS,
638 	},
639 };
640 
641 static int __init iTCO_wdt_init_module(void)
642 {
643 	pr_info("Intel TCO WatchDog Timer Driver v%s\n", DRV_VERSION);
644 
645 	return platform_driver_register(&iTCO_wdt_driver);
646 }
647 
648 static void __exit iTCO_wdt_cleanup_module(void)
649 {
650 	platform_driver_unregister(&iTCO_wdt_driver);
651 	pr_info("Watchdog Module Unloaded\n");
652 }
653 
654 module_init(iTCO_wdt_init_module);
655 module_exit(iTCO_wdt_cleanup_module);
656 
657 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
658 MODULE_DESCRIPTION("Intel TCO WatchDog Timer Driver");
659 MODULE_VERSION(DRV_VERSION);
660 MODULE_LICENSE("GPL");
661 MODULE_ALIAS("platform:" DRV_NAME);
662