xref: /openbmc/linux/drivers/watchdog/sp5100_tco.c (revision 224d80c5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	sp5100_tco :	TCO timer driver for sp5100 chipsets
4  *
5  *	(c) Copyright 2009 Google Inc., All Rights Reserved.
6  *
7  *	Based on i8xx_tco.c:
8  *	(c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
9  *	Reserved.
10  *				https://www.kernelconcepts.de
11  *
12  *	See AMD Publication 43009 "AMD SB700/710/750 Register Reference Guide",
13  *	    AMD Publication 44413 "AMD SP5100 Register Reference Guide"
14  *	    AMD Publication 45482 "AMD SB800-Series Southbridges Register
15  *	                                                      Reference Guide"
16  *	    AMD Publication 48751 "BIOS and Kernel Developer’s Guide (BKDG)
17  *				for AMD Family 16h Models 00h-0Fh Processors"
18  *	    AMD Publication 51192 "AMD Bolton FCH Register Reference Guide"
19  *	    AMD Publication 52740 "BIOS and Kernel Developer’s Guide (BKDG)
20  *				for AMD Family 16h Models 30h-3Fh Processors"
21  *	    AMD Publication 55570-B1-PUB "Processor Programming Reference (PPR)
22  *				for AMD Family 17h Model 18h, Revision B1
23  *				Processors (PUB)
24  *	    AMD Publication 55772-A1-PUB "Processor Programming Reference (PPR)
25  *				for AMD Family 17h Model 20h, Revision A1
26  *				Processors (PUB)
27  */
28 
29 /*
30  *	Includes, defines, variables, module parameters, ...
31  */
32 
33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34 
35 #include <linux/init.h>
36 #include <linux/io.h>
37 #include <linux/ioport.h>
38 #include <linux/module.h>
39 #include <linux/moduleparam.h>
40 #include <linux/pci.h>
41 #include <linux/platform_device.h>
42 #include <linux/types.h>
43 #include <linux/watchdog.h>
44 
45 #include "sp5100_tco.h"
46 
47 #define TCO_DRIVER_NAME	"sp5100-tco"
48 
49 /* internal variables */
50 
51 enum tco_reg_layout {
52 	sp5100, sb800, efch, efch_mmio
53 };
54 
55 struct sp5100_tco {
56 	struct watchdog_device wdd;
57 	void __iomem *tcobase;
58 	enum tco_reg_layout tco_reg_layout;
59 };
60 
61 /* the watchdog platform device */
62 static struct platform_device *sp5100_tco_platform_device;
63 /* the associated PCI device */
64 static struct pci_dev *sp5100_tco_pci;
65 
66 /* module parameters */
67 
68 #define WATCHDOG_ACTION 0
69 static bool action = WATCHDOG_ACTION;
70 module_param(action, bool, 0);
71 MODULE_PARM_DESC(action, "Action taken when watchdog expires, 0 to reset, 1 to poweroff (default="
72 		 __MODULE_STRING(WATCHDOG_ACTION) ")");
73 
74 #define WATCHDOG_HEARTBEAT 60	/* 60 sec default heartbeat. */
75 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
76 module_param(heartbeat, int, 0);
77 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
78 		 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
79 
80 static bool nowayout = WATCHDOG_NOWAYOUT;
81 module_param(nowayout, bool, 0);
82 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started."
83 		" (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
84 
85 /*
86  * Some TCO specific functions
87  */
88 
89 static enum tco_reg_layout tco_reg_layout(struct pci_dev *dev)
90 {
91 	if (dev->vendor == PCI_VENDOR_ID_ATI &&
92 	    dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
93 	    dev->revision < 0x40) {
94 		return sp5100;
95 	} else if (dev->vendor == PCI_VENDOR_ID_AMD &&
96 	    sp5100_tco_pci->device == PCI_DEVICE_ID_AMD_KERNCZ_SMBUS &&
97 	    sp5100_tco_pci->revision >= AMD_ZEN_SMBUS_PCI_REV) {
98 		return efch_mmio;
99 	} else if (dev->vendor == PCI_VENDOR_ID_AMD &&
100 	    ((dev->device == PCI_DEVICE_ID_AMD_HUDSON2_SMBUS &&
101 	     dev->revision >= 0x41) ||
102 	    (dev->device == PCI_DEVICE_ID_AMD_KERNCZ_SMBUS &&
103 	     dev->revision >= 0x49))) {
104 		return efch;
105 	}
106 	return sb800;
107 }
108 
109 static int tco_timer_start(struct watchdog_device *wdd)
110 {
111 	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
112 	u32 val;
113 
114 	val = readl(SP5100_WDT_CONTROL(tco->tcobase));
115 	val |= SP5100_WDT_START_STOP_BIT;
116 	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
117 
118 	/* This must be a distinct write. */
119 	val |= SP5100_WDT_TRIGGER_BIT;
120 	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
121 
122 	return 0;
123 }
124 
125 static int tco_timer_stop(struct watchdog_device *wdd)
126 {
127 	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
128 	u32 val;
129 
130 	val = readl(SP5100_WDT_CONTROL(tco->tcobase));
131 	val &= ~SP5100_WDT_START_STOP_BIT;
132 	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
133 
134 	return 0;
135 }
136 
137 static int tco_timer_ping(struct watchdog_device *wdd)
138 {
139 	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
140 	u32 val;
141 
142 	val = readl(SP5100_WDT_CONTROL(tco->tcobase));
143 	val |= SP5100_WDT_TRIGGER_BIT;
144 	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
145 
146 	return 0;
147 }
148 
149 static int tco_timer_set_timeout(struct watchdog_device *wdd,
150 				 unsigned int t)
151 {
152 	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
153 
154 	/* Write new heartbeat to watchdog */
155 	writel(t, SP5100_WDT_COUNT(tco->tcobase));
156 
157 	wdd->timeout = t;
158 
159 	return 0;
160 }
161 
162 static unsigned int tco_timer_get_timeleft(struct watchdog_device *wdd)
163 {
164 	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
165 
166 	return readl(SP5100_WDT_COUNT(tco->tcobase));
167 }
168 
169 static u8 sp5100_tco_read_pm_reg8(u8 index)
170 {
171 	outb(index, SP5100_IO_PM_INDEX_REG);
172 	return inb(SP5100_IO_PM_DATA_REG);
173 }
174 
175 static void sp5100_tco_update_pm_reg8(u8 index, u8 reset, u8 set)
176 {
177 	u8 val;
178 
179 	outb(index, SP5100_IO_PM_INDEX_REG);
180 	val = inb(SP5100_IO_PM_DATA_REG);
181 	val &= reset;
182 	val |= set;
183 	outb(val, SP5100_IO_PM_DATA_REG);
184 }
185 
186 static void tco_timer_enable(struct sp5100_tco *tco)
187 {
188 	u32 val;
189 
190 	switch (tco->tco_reg_layout) {
191 	case sb800:
192 		/* For SB800 or later */
193 		/* Set the Watchdog timer resolution to 1 sec */
194 		sp5100_tco_update_pm_reg8(SB800_PM_WATCHDOG_CONFIG,
195 					  0xff, SB800_PM_WATCHDOG_SECOND_RES);
196 
197 		/* Enable watchdog decode bit and watchdog timer */
198 		sp5100_tco_update_pm_reg8(SB800_PM_WATCHDOG_CONTROL,
199 					  ~SB800_PM_WATCHDOG_DISABLE,
200 					  SB800_PCI_WATCHDOG_DECODE_EN);
201 		break;
202 	case sp5100:
203 		/* For SP5100 or SB7x0 */
204 		/* Enable watchdog decode bit */
205 		pci_read_config_dword(sp5100_tco_pci,
206 				      SP5100_PCI_WATCHDOG_MISC_REG,
207 				      &val);
208 
209 		val |= SP5100_PCI_WATCHDOG_DECODE_EN;
210 
211 		pci_write_config_dword(sp5100_tco_pci,
212 				       SP5100_PCI_WATCHDOG_MISC_REG,
213 				       val);
214 
215 		/* Enable Watchdog timer and set the resolution to 1 sec */
216 		sp5100_tco_update_pm_reg8(SP5100_PM_WATCHDOG_CONTROL,
217 					  ~SP5100_PM_WATCHDOG_DISABLE,
218 					  SP5100_PM_WATCHDOG_SECOND_RES);
219 		break;
220 	case efch:
221 		/* Set the Watchdog timer resolution to 1 sec and enable */
222 		sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN3,
223 					  ~EFCH_PM_WATCHDOG_DISABLE,
224 					  EFCH_PM_DECODEEN_SECOND_RES);
225 		break;
226 	default:
227 		break;
228 	}
229 }
230 
231 static u32 sp5100_tco_read_pm_reg32(u8 index)
232 {
233 	u32 val = 0;
234 	int i;
235 
236 	for (i = 3; i >= 0; i--)
237 		val = (val << 8) + sp5100_tco_read_pm_reg8(index + i);
238 
239 	return val;
240 }
241 
242 static u32 sp5100_tco_request_region(struct device *dev,
243 				     u32 mmio_addr,
244 				     const char *dev_name)
245 {
246 	if (!devm_request_mem_region(dev, mmio_addr, SP5100_WDT_MEM_MAP_SIZE,
247 				     dev_name)) {
248 		dev_dbg(dev, "MMIO address 0x%08x already in use\n", mmio_addr);
249 		return 0;
250 	}
251 
252 	return mmio_addr;
253 }
254 
255 static u32 sp5100_tco_prepare_base(struct sp5100_tco *tco,
256 				   u32 mmio_addr,
257 				   u32 alt_mmio_addr,
258 				   const char *dev_name)
259 {
260 	struct device *dev = tco->wdd.parent;
261 
262 	dev_dbg(dev, "Got 0x%08x from SBResource_MMIO register\n", mmio_addr);
263 
264 	if (!mmio_addr && !alt_mmio_addr)
265 		return -ENODEV;
266 
267 	/* Check for MMIO address and alternate MMIO address conflicts */
268 	if (mmio_addr)
269 		mmio_addr = sp5100_tco_request_region(dev, mmio_addr, dev_name);
270 
271 	if (!mmio_addr && alt_mmio_addr)
272 		mmio_addr = sp5100_tco_request_region(dev, alt_mmio_addr, dev_name);
273 
274 	if (!mmio_addr) {
275 		dev_err(dev, "Failed to reserve MMIO or alternate MMIO region\n");
276 		return -EBUSY;
277 	}
278 
279 	tco->tcobase = devm_ioremap(dev, mmio_addr, SP5100_WDT_MEM_MAP_SIZE);
280 	if (!tco->tcobase) {
281 		dev_err(dev, "MMIO address 0x%08x failed mapping\n", mmio_addr);
282 		devm_release_mem_region(dev, mmio_addr, SP5100_WDT_MEM_MAP_SIZE);
283 		return -ENOMEM;
284 	}
285 
286 	dev_info(dev, "Using 0x%08x for watchdog MMIO address\n", mmio_addr);
287 
288 	return 0;
289 }
290 
291 static int sp5100_tco_timer_init(struct sp5100_tco *tco)
292 {
293 	struct watchdog_device *wdd = &tco->wdd;
294 	struct device *dev = wdd->parent;
295 	u32 val;
296 
297 	val = readl(SP5100_WDT_CONTROL(tco->tcobase));
298 	if (val & SP5100_WDT_DISABLED) {
299 		dev_err(dev, "Watchdog hardware is disabled\n");
300 		return -ENODEV;
301 	}
302 
303 	/*
304 	 * Save WatchDogFired status, because WatchDogFired flag is
305 	 * cleared here.
306 	 */
307 	if (val & SP5100_WDT_FIRED)
308 		wdd->bootstatus = WDIOF_CARDRESET;
309 
310 	/* Set watchdog action */
311 	if (action)
312 		val |= SP5100_WDT_ACTION_RESET;
313 	else
314 		val &= ~SP5100_WDT_ACTION_RESET;
315 	writel(val, SP5100_WDT_CONTROL(tco->tcobase));
316 
317 	/* Set a reasonable heartbeat before we stop the timer */
318 	tco_timer_set_timeout(wdd, wdd->timeout);
319 
320 	/*
321 	 * Stop the TCO before we change anything so we don't race with
322 	 * a zeroed timer.
323 	 */
324 	tco_timer_stop(wdd);
325 
326 	return 0;
327 }
328 
329 static u8 efch_read_pm_reg8(void __iomem *addr, u8 index)
330 {
331 	return readb(addr + index);
332 }
333 
334 static void efch_update_pm_reg8(void __iomem *addr, u8 index, u8 reset, u8 set)
335 {
336 	u8 val;
337 
338 	val = readb(addr + index);
339 	val &= reset;
340 	val |= set;
341 	writeb(val, addr + index);
342 }
343 
344 static void tco_timer_enable_mmio(void __iomem *addr)
345 {
346 	efch_update_pm_reg8(addr, EFCH_PM_DECODEEN3,
347 			    ~EFCH_PM_WATCHDOG_DISABLE,
348 			    EFCH_PM_DECODEEN_SECOND_RES);
349 }
350 
351 static int sp5100_tco_setupdevice_mmio(struct device *dev,
352 				       struct watchdog_device *wdd)
353 {
354 	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
355 	const char *dev_name = SB800_DEVNAME;
356 	u32 mmio_addr = 0, alt_mmio_addr = 0;
357 	struct resource *res;
358 	void __iomem *addr;
359 	int ret;
360 	u32 val;
361 
362 	res = request_mem_region_muxed(EFCH_PM_ACPI_MMIO_PM_ADDR,
363 				       EFCH_PM_ACPI_MMIO_PM_SIZE,
364 				       "sp5100_tco");
365 
366 	if (!res) {
367 		dev_err(dev,
368 			"Memory region 0x%08x already in use\n",
369 			EFCH_PM_ACPI_MMIO_PM_ADDR);
370 		return -EBUSY;
371 	}
372 
373 	addr = ioremap(EFCH_PM_ACPI_MMIO_PM_ADDR, EFCH_PM_ACPI_MMIO_PM_SIZE);
374 	if (!addr) {
375 		dev_err(dev, "Address mapping failed\n");
376 		ret = -ENOMEM;
377 		goto out;
378 	}
379 
380 	/*
381 	 * EFCH_PM_DECODEEN_WDT_TMREN is dual purpose. This bitfield
382 	 * enables sp5100_tco register MMIO space decoding. The bitfield
383 	 * also starts the timer operation. Enable if not already enabled.
384 	 */
385 	val = efch_read_pm_reg8(addr, EFCH_PM_DECODEEN);
386 	if (!(val & EFCH_PM_DECODEEN_WDT_TMREN)) {
387 		efch_update_pm_reg8(addr, EFCH_PM_DECODEEN, 0xff,
388 				    EFCH_PM_DECODEEN_WDT_TMREN);
389 	}
390 
391 	/* Error if the timer could not be enabled */
392 	val = efch_read_pm_reg8(addr, EFCH_PM_DECODEEN);
393 	if (!(val & EFCH_PM_DECODEEN_WDT_TMREN)) {
394 		dev_err(dev, "Failed to enable the timer\n");
395 		ret = -EFAULT;
396 		goto out;
397 	}
398 
399 	mmio_addr = EFCH_PM_WDT_ADDR;
400 
401 	/* Determine alternate MMIO base address */
402 	val = efch_read_pm_reg8(addr, EFCH_PM_ISACONTROL);
403 	if (val & EFCH_PM_ISACONTROL_MMIOEN)
404 		alt_mmio_addr = EFCH_PM_ACPI_MMIO_ADDR +
405 			EFCH_PM_ACPI_MMIO_WDT_OFFSET;
406 
407 	ret = sp5100_tco_prepare_base(tco, mmio_addr, alt_mmio_addr, dev_name);
408 	if (!ret) {
409 		tco_timer_enable_mmio(addr);
410 		ret = sp5100_tco_timer_init(tco);
411 	}
412 
413 out:
414 	if (addr)
415 		iounmap(addr);
416 
417 	release_resource(res);
418 	kfree(res);
419 
420 	return ret;
421 }
422 
423 static int sp5100_tco_setupdevice(struct device *dev,
424 				  struct watchdog_device *wdd)
425 {
426 	struct sp5100_tco *tco = watchdog_get_drvdata(wdd);
427 	const char *dev_name;
428 	u32 mmio_addr = 0, val;
429 	u32 alt_mmio_addr = 0;
430 	int ret;
431 
432 	if (tco->tco_reg_layout == efch_mmio)
433 		return sp5100_tco_setupdevice_mmio(dev, wdd);
434 
435 	/* Request the IO ports used by this driver */
436 	if (!request_muxed_region(SP5100_IO_PM_INDEX_REG,
437 				  SP5100_PM_IOPORTS_SIZE, "sp5100_tco")) {
438 		dev_err(dev, "I/O address 0x%04x already in use\n",
439 			SP5100_IO_PM_INDEX_REG);
440 		return -EBUSY;
441 	}
442 
443 	/*
444 	 * Determine type of southbridge chipset.
445 	 */
446 	switch (tco->tco_reg_layout) {
447 	case sp5100:
448 		dev_name = SP5100_DEVNAME;
449 		mmio_addr = sp5100_tco_read_pm_reg32(SP5100_PM_WATCHDOG_BASE) &
450 								0xfffffff8;
451 
452 		/*
453 		 * Secondly, find the watchdog timer MMIO address
454 		 * from SBResource_MMIO register.
455 		 */
456 
457 		/* Read SBResource_MMIO from PCI config(PCI_Reg: 9Ch) */
458 		pci_read_config_dword(sp5100_tco_pci,
459 				      SP5100_SB_RESOURCE_MMIO_BASE,
460 				      &val);
461 
462 		/* Verify MMIO is enabled and using bar0 */
463 		if ((val & SB800_ACPI_MMIO_MASK) == SB800_ACPI_MMIO_DECODE_EN)
464 			alt_mmio_addr = (val & ~0xfff) + SB800_PM_WDT_MMIO_OFFSET;
465 		break;
466 	case sb800:
467 		dev_name = SB800_DEVNAME;
468 		mmio_addr = sp5100_tco_read_pm_reg32(SB800_PM_WATCHDOG_BASE) &
469 								0xfffffff8;
470 
471 		/* Read SBResource_MMIO from AcpiMmioEn(PM_Reg: 24h) */
472 		val = sp5100_tco_read_pm_reg32(SB800_PM_ACPI_MMIO_EN);
473 
474 		/* Verify MMIO is enabled and using bar0 */
475 		if ((val & SB800_ACPI_MMIO_MASK) == SB800_ACPI_MMIO_DECODE_EN)
476 			alt_mmio_addr = (val & ~0xfff) + SB800_PM_WDT_MMIO_OFFSET;
477 		break;
478 	case efch:
479 		dev_name = SB800_DEVNAME;
480 		val = sp5100_tco_read_pm_reg8(EFCH_PM_DECODEEN);
481 		if (val & EFCH_PM_DECODEEN_WDT_TMREN)
482 			mmio_addr = EFCH_PM_WDT_ADDR;
483 
484 		val = sp5100_tco_read_pm_reg8(EFCH_PM_ISACONTROL);
485 		if (val & EFCH_PM_ISACONTROL_MMIOEN)
486 			alt_mmio_addr = EFCH_PM_ACPI_MMIO_ADDR +
487 				EFCH_PM_ACPI_MMIO_WDT_OFFSET;
488 		break;
489 	default:
490 		return -ENODEV;
491 	}
492 
493 	ret = sp5100_tco_prepare_base(tco, mmio_addr, alt_mmio_addr, dev_name);
494 	if (!ret) {
495 		/* Setup the watchdog timer */
496 		tco_timer_enable(tco);
497 		ret = sp5100_tco_timer_init(tco);
498 	}
499 
500 	release_region(SP5100_IO_PM_INDEX_REG, SP5100_PM_IOPORTS_SIZE);
501 	return ret;
502 }
503 
504 static struct watchdog_info sp5100_tco_wdt_info = {
505 	.identity = "SP5100 TCO timer",
506 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
507 };
508 
509 static const struct watchdog_ops sp5100_tco_wdt_ops = {
510 	.owner = THIS_MODULE,
511 	.start = tco_timer_start,
512 	.stop = tco_timer_stop,
513 	.ping = tco_timer_ping,
514 	.set_timeout = tco_timer_set_timeout,
515 	.get_timeleft = tco_timer_get_timeleft,
516 };
517 
518 static int sp5100_tco_probe(struct platform_device *pdev)
519 {
520 	struct device *dev = &pdev->dev;
521 	struct watchdog_device *wdd;
522 	struct sp5100_tco *tco;
523 	int ret;
524 
525 	tco = devm_kzalloc(dev, sizeof(*tco), GFP_KERNEL);
526 	if (!tco)
527 		return -ENOMEM;
528 
529 	tco->tco_reg_layout = tco_reg_layout(sp5100_tco_pci);
530 
531 	wdd = &tco->wdd;
532 	wdd->parent = dev;
533 	wdd->info = &sp5100_tco_wdt_info;
534 	wdd->ops = &sp5100_tco_wdt_ops;
535 	wdd->timeout = WATCHDOG_HEARTBEAT;
536 	wdd->min_timeout = 1;
537 	wdd->max_timeout = 0xffff;
538 
539 	watchdog_init_timeout(wdd, heartbeat, NULL);
540 	watchdog_set_nowayout(wdd, nowayout);
541 	watchdog_stop_on_reboot(wdd);
542 	watchdog_stop_on_unregister(wdd);
543 	watchdog_set_drvdata(wdd, tco);
544 
545 	ret = sp5100_tco_setupdevice(dev, wdd);
546 	if (ret)
547 		return ret;
548 
549 	ret = devm_watchdog_register_device(dev, wdd);
550 	if (ret)
551 		return ret;
552 
553 	/* Show module parameters */
554 	dev_info(dev, "initialized. heartbeat=%d sec (nowayout=%d)\n",
555 		 wdd->timeout, nowayout);
556 
557 	return 0;
558 }
559 
560 static struct platform_driver sp5100_tco_driver = {
561 	.probe		= sp5100_tco_probe,
562 	.driver		= {
563 		.name	= TCO_DRIVER_NAME,
564 	},
565 };
566 
567 /*
568  * Data for PCI driver interface
569  *
570  * This data only exists for exporting the supported
571  * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
572  * register a pci_driver, because someone else might
573  * want to register another driver on the same PCI id.
574  */
575 static const struct pci_device_id sp5100_tco_pci_tbl[] = {
576 	{ PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS, PCI_ANY_ID,
577 	  PCI_ANY_ID, },
578 	{ PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_HUDSON2_SMBUS, PCI_ANY_ID,
579 	  PCI_ANY_ID, },
580 	{ PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, PCI_ANY_ID,
581 	  PCI_ANY_ID, },
582 	{ 0, },			/* End of list */
583 };
584 MODULE_DEVICE_TABLE(pci, sp5100_tco_pci_tbl);
585 
586 static int __init sp5100_tco_init(void)
587 {
588 	struct pci_dev *dev = NULL;
589 	int err;
590 
591 	/* Match the PCI device */
592 	for_each_pci_dev(dev) {
593 		if (pci_match_id(sp5100_tco_pci_tbl, dev) != NULL) {
594 			sp5100_tco_pci = dev;
595 			break;
596 		}
597 	}
598 
599 	if (!sp5100_tco_pci)
600 		return -ENODEV;
601 
602 	pr_info("SP5100/SB800 TCO WatchDog Timer Driver\n");
603 
604 	err = platform_driver_register(&sp5100_tco_driver);
605 	if (err)
606 		return err;
607 
608 	sp5100_tco_platform_device =
609 		platform_device_register_simple(TCO_DRIVER_NAME, -1, NULL, 0);
610 	if (IS_ERR(sp5100_tco_platform_device)) {
611 		err = PTR_ERR(sp5100_tco_platform_device);
612 		goto unreg_platform_driver;
613 	}
614 
615 	return 0;
616 
617 unreg_platform_driver:
618 	platform_driver_unregister(&sp5100_tco_driver);
619 	return err;
620 }
621 
622 static void __exit sp5100_tco_exit(void)
623 {
624 	platform_device_unregister(sp5100_tco_platform_device);
625 	platform_driver_unregister(&sp5100_tco_driver);
626 }
627 
628 module_init(sp5100_tco_init);
629 module_exit(sp5100_tco_exit);
630 
631 MODULE_AUTHOR("Priyanka Gupta");
632 MODULE_DESCRIPTION("TCO timer driver for SP5100/SB800 chipset");
633 MODULE_LICENSE("GPL");
634