xref: /linux/drivers/watchdog/hpwdt.c (revision eeca9fad52fc4bfdf42c38bfcf383e932eb3e9d6)
1 /*
2  *	HP WatchDog Driver
3  *	based on
4  *
5  *	SoftDog	0.05:	A Software Watchdog Device
6  *
7  *	(c) Copyright 2007 Hewlett-Packard Development Company, L.P.
8  *	Thomas Mingarelli <thomas.mingarelli@hp.com>
9  *
10  *	This program is free software; you can redistribute it and/or
11  *	modify it under the terms of the GNU General Public License
12  *	version 2 as published by the Free Software Foundation
13  *
14  */
15 
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 
18 #include <linux/device.h>
19 #include <linux/fs.h>
20 #include <linux/init.h>
21 #include <linux/io.h>
22 #include <linux/bitops.h>
23 #include <linux/kernel.h>
24 #include <linux/miscdevice.h>
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27 #include <linux/pci.h>
28 #include <linux/pci_ids.h>
29 #include <linux/types.h>
30 #include <linux/uaccess.h>
31 #include <linux/watchdog.h>
32 #ifdef CONFIG_HPWDT_NMI_DECODING
33 #include <linux/dmi.h>
34 #include <linux/spinlock.h>
35 #include <linux/nmi.h>
36 #include <linux/kdebug.h>
37 #include <linux/notifier.h>
38 #include <asm/cacheflush.h>
39 #endif /* CONFIG_HPWDT_NMI_DECODING */
40 #include <asm/nmi.h>
41 
42 #define HPWDT_VERSION			"1.3.2"
43 #define SECS_TO_TICKS(secs)		((secs) * 1000 / 128)
44 #define TICKS_TO_SECS(ticks)		((ticks) * 128 / 1000)
45 #define HPWDT_MAX_TIMER			TICKS_TO_SECS(65535)
46 #define DEFAULT_MARGIN			30
47 
48 static unsigned int soft_margin = DEFAULT_MARGIN;	/* in seconds */
49 static unsigned int reload;			/* the computed soft_margin */
50 static bool nowayout = WATCHDOG_NOWAYOUT;
51 static char expect_release;
52 static unsigned long hpwdt_is_open;
53 
54 static void __iomem *pci_mem_addr;		/* the PCI-memory address */
55 static unsigned long __iomem *hpwdt_timer_reg;
56 static unsigned long __iomem *hpwdt_timer_con;
57 
58 static DEFINE_PCI_DEVICE_TABLE(hpwdt_devices) = {
59 	{ PCI_DEVICE(PCI_VENDOR_ID_COMPAQ, 0xB203) },	/* iLO2 */
60 	{ PCI_DEVICE(PCI_VENDOR_ID_HP, 0x3306) },	/* iLO3 */
61 	{0},			/* terminate list */
62 };
63 MODULE_DEVICE_TABLE(pci, hpwdt_devices);
64 
65 #ifdef CONFIG_HPWDT_NMI_DECODING
66 #define PCI_BIOS32_SD_VALUE		0x5F32335F	/* "_32_" */
67 #define CRU_BIOS_SIGNATURE_VALUE	0x55524324
68 #define PCI_BIOS32_PARAGRAPH_LEN	16
69 #define PCI_ROM_BASE1			0x000F0000
70 #define ROM_SIZE			0x10000
71 
72 struct bios32_service_dir {
73 	u32 signature;
74 	u32 entry_point;
75 	u8 revision;
76 	u8 length;
77 	u8 checksum;
78 	u8 reserved[5];
79 };
80 
81 /* type 212 */
82 struct smbios_cru64_info {
83 	u8 type;
84 	u8 byte_length;
85 	u16 handle;
86 	u32 signature;
87 	u64 physical_address;
88 	u32 double_length;
89 	u32 double_offset;
90 };
91 #define SMBIOS_CRU64_INFORMATION	212
92 
93 /* type 219 */
94 struct smbios_proliant_info {
95 	u8 type;
96 	u8 byte_length;
97 	u16 handle;
98 	u32 power_features;
99 	u32 omega_features;
100 	u32 reserved;
101 	u32 misc_features;
102 };
103 #define SMBIOS_ICRU_INFORMATION		219
104 
105 
106 struct cmn_registers {
107 	union {
108 		struct {
109 			u8 ral;
110 			u8 rah;
111 			u16 rea2;
112 		};
113 		u32 reax;
114 	} u1;
115 	union {
116 		struct {
117 			u8 rbl;
118 			u8 rbh;
119 			u8 reb2l;
120 			u8 reb2h;
121 		};
122 		u32 rebx;
123 	} u2;
124 	union {
125 		struct {
126 			u8 rcl;
127 			u8 rch;
128 			u16 rec2;
129 		};
130 		u32 recx;
131 	} u3;
132 	union {
133 		struct {
134 			u8 rdl;
135 			u8 rdh;
136 			u16 red2;
137 		};
138 		u32 redx;
139 	} u4;
140 
141 	u32 resi;
142 	u32 redi;
143 	u16 rds;
144 	u16 res;
145 	u32 reflags;
146 }  __attribute__((packed));
147 
148 static unsigned int hpwdt_nmi_decoding;
149 static unsigned int allow_kdump = 1;
150 static unsigned int is_icru;
151 static unsigned int is_uefi;
152 static DEFINE_SPINLOCK(rom_lock);
153 static void *cru_rom_addr;
154 static struct cmn_registers cmn_regs;
155 
156 extern asmlinkage void asminline_call(struct cmn_registers *pi86Regs,
157 						unsigned long *pRomEntry);
158 
159 #ifdef CONFIG_X86_32
160 /* --32 Bit Bios------------------------------------------------------------ */
161 
162 #define HPWDT_ARCH	32
163 
164 asm(".text                          \n\t"
165     ".align 4                       \n"
166     "asminline_call:                \n\t"
167     "pushl       %ebp               \n\t"
168     "movl        %esp, %ebp         \n\t"
169     "pusha                          \n\t"
170     "pushf                          \n\t"
171     "push        %es                \n\t"
172     "push        %ds                \n\t"
173     "pop         %es                \n\t"
174     "movl        8(%ebp),%eax       \n\t"
175     "movl        4(%eax),%ebx       \n\t"
176     "movl        8(%eax),%ecx       \n\t"
177     "movl        12(%eax),%edx      \n\t"
178     "movl        16(%eax),%esi      \n\t"
179     "movl        20(%eax),%edi      \n\t"
180     "movl        (%eax),%eax        \n\t"
181     "push        %cs                \n\t"
182     "call        *12(%ebp)          \n\t"
183     "pushf                          \n\t"
184     "pushl       %eax               \n\t"
185     "movl        8(%ebp),%eax       \n\t"
186     "movl        %ebx,4(%eax)       \n\t"
187     "movl        %ecx,8(%eax)       \n\t"
188     "movl        %edx,12(%eax)      \n\t"
189     "movl        %esi,16(%eax)      \n\t"
190     "movl        %edi,20(%eax)      \n\t"
191     "movw        %ds,24(%eax)       \n\t"
192     "movw        %es,26(%eax)       \n\t"
193     "popl        %ebx               \n\t"
194     "movl        %ebx,(%eax)        \n\t"
195     "popl        %ebx               \n\t"
196     "movl        %ebx,28(%eax)      \n\t"
197     "pop         %es                \n\t"
198     "popf                           \n\t"
199     "popa                           \n\t"
200     "leave                          \n\t"
201     "ret                            \n\t"
202     ".previous");
203 
204 
205 /*
206  *	cru_detect
207  *
208  *	Routine Description:
209  *	This function uses the 32-bit BIOS Service Directory record to
210  *	search for a $CRU record.
211  *
212  *	Return Value:
213  *	0        :  SUCCESS
214  *	<0       :  FAILURE
215  */
216 static int cru_detect(unsigned long map_entry,
217 	unsigned long map_offset)
218 {
219 	void *bios32_map;
220 	unsigned long *bios32_entrypoint;
221 	unsigned long cru_physical_address;
222 	unsigned long cru_length;
223 	unsigned long physical_bios_base = 0;
224 	unsigned long physical_bios_offset = 0;
225 	int retval = -ENODEV;
226 
227 	bios32_map = ioremap(map_entry, (2 * PAGE_SIZE));
228 
229 	if (bios32_map == NULL)
230 		return -ENODEV;
231 
232 	bios32_entrypoint = bios32_map + map_offset;
233 
234 	cmn_regs.u1.reax = CRU_BIOS_SIGNATURE_VALUE;
235 
236 	set_memory_x((unsigned long)bios32_map, 2);
237 	asminline_call(&cmn_regs, bios32_entrypoint);
238 
239 	if (cmn_regs.u1.ral != 0) {
240 		pr_warn("Call succeeded but with an error: 0x%x\n",
241 			cmn_regs.u1.ral);
242 	} else {
243 		physical_bios_base = cmn_regs.u2.rebx;
244 		physical_bios_offset = cmn_regs.u4.redx;
245 		cru_length = cmn_regs.u3.recx;
246 		cru_physical_address =
247 			physical_bios_base + physical_bios_offset;
248 
249 		/* If the values look OK, then map it in. */
250 		if ((physical_bios_base + physical_bios_offset)) {
251 			cru_rom_addr =
252 				ioremap(cru_physical_address, cru_length);
253 			if (cru_rom_addr) {
254 				set_memory_x((unsigned long)cru_rom_addr & PAGE_MASK,
255 					(cru_length + PAGE_SIZE - 1) >> PAGE_SHIFT);
256 				retval = 0;
257 			}
258 		}
259 
260 		pr_debug("CRU Base Address:   0x%lx\n", physical_bios_base);
261 		pr_debug("CRU Offset Address: 0x%lx\n", physical_bios_offset);
262 		pr_debug("CRU Length:         0x%lx\n", cru_length);
263 		pr_debug("CRU Mapped Address: %p\n", &cru_rom_addr);
264 	}
265 	iounmap(bios32_map);
266 	return retval;
267 }
268 
269 /*
270  *	bios_checksum
271  */
272 static int bios_checksum(const char __iomem *ptr, int len)
273 {
274 	char sum = 0;
275 	int i;
276 
277 	/*
278 	 * calculate checksum of size bytes. This should add up
279 	 * to zero if we have a valid header.
280 	 */
281 	for (i = 0; i < len; i++)
282 		sum += ptr[i];
283 
284 	return ((sum == 0) && (len > 0));
285 }
286 
287 /*
288  *	bios32_present
289  *
290  *	Routine Description:
291  *	This function finds the 32-bit BIOS Service Directory
292  *
293  *	Return Value:
294  *	0        :  SUCCESS
295  *	<0       :  FAILURE
296  */
297 static int bios32_present(const char __iomem *p)
298 {
299 	struct bios32_service_dir *bios_32_ptr;
300 	int length;
301 	unsigned long map_entry, map_offset;
302 
303 	bios_32_ptr = (struct bios32_service_dir *) p;
304 
305 	/*
306 	 * Search for signature by checking equal to the swizzled value
307 	 * instead of calling another routine to perform a strcmp.
308 	 */
309 	if (bios_32_ptr->signature == PCI_BIOS32_SD_VALUE) {
310 		length = bios_32_ptr->length * PCI_BIOS32_PARAGRAPH_LEN;
311 		if (bios_checksum(p, length)) {
312 			/*
313 			 * According to the spec, we're looking for the
314 			 * first 4KB-aligned address below the entrypoint
315 			 * listed in the header. The Service Directory code
316 			 * is guaranteed to occupy no more than 2 4KB pages.
317 			 */
318 			map_entry = bios_32_ptr->entry_point & ~(PAGE_SIZE - 1);
319 			map_offset = bios_32_ptr->entry_point - map_entry;
320 
321 			return cru_detect(map_entry, map_offset);
322 		}
323 	}
324 	return -ENODEV;
325 }
326 
327 static int detect_cru_service(void)
328 {
329 	char __iomem *p, *q;
330 	int rc = -1;
331 
332 	/*
333 	 * Search from 0x0f0000 through 0x0fffff, inclusive.
334 	 */
335 	p = ioremap(PCI_ROM_BASE1, ROM_SIZE);
336 	if (p == NULL)
337 		return -ENOMEM;
338 
339 	for (q = p; q < p + ROM_SIZE; q += 16) {
340 		rc = bios32_present(q);
341 		if (!rc)
342 			break;
343 	}
344 	iounmap(p);
345 	return rc;
346 }
347 /* ------------------------------------------------------------------------- */
348 #endif /* CONFIG_X86_32 */
349 #ifdef CONFIG_X86_64
350 /* --64 Bit Bios------------------------------------------------------------ */
351 
352 #define HPWDT_ARCH	64
353 
354 asm(".text                      \n\t"
355     ".align 4                   \n"
356     "asminline_call:            \n\t"
357     "pushq      %rbp            \n\t"
358     "movq       %rsp, %rbp      \n\t"
359     "pushq      %rax            \n\t"
360     "pushq      %rbx            \n\t"
361     "pushq      %rdx            \n\t"
362     "pushq      %r12            \n\t"
363     "pushq      %r9             \n\t"
364     "movq       %rsi, %r12      \n\t"
365     "movq       %rdi, %r9       \n\t"
366     "movl       4(%r9),%ebx     \n\t"
367     "movl       8(%r9),%ecx     \n\t"
368     "movl       12(%r9),%edx    \n\t"
369     "movl       16(%r9),%esi    \n\t"
370     "movl       20(%r9),%edi    \n\t"
371     "movl       (%r9),%eax      \n\t"
372     "call       *%r12           \n\t"
373     "pushfq                     \n\t"
374     "popq        %r12           \n\t"
375     "movl       %eax, (%r9)     \n\t"
376     "movl       %ebx, 4(%r9)    \n\t"
377     "movl       %ecx, 8(%r9)    \n\t"
378     "movl       %edx, 12(%r9)   \n\t"
379     "movl       %esi, 16(%r9)   \n\t"
380     "movl       %edi, 20(%r9)   \n\t"
381     "movq       %r12, %rax      \n\t"
382     "movl       %eax, 28(%r9)   \n\t"
383     "popq       %r9             \n\t"
384     "popq       %r12            \n\t"
385     "popq       %rdx            \n\t"
386     "popq       %rbx            \n\t"
387     "popq       %rax            \n\t"
388     "leave                      \n\t"
389     "ret                        \n\t"
390     ".previous");
391 
392 /*
393  *	dmi_find_cru
394  *
395  *	Routine Description:
396  *	This function checks whether or not a SMBIOS/DMI record is
397  *	the 64bit CRU info or not
398  */
399 static void dmi_find_cru(const struct dmi_header *dm, void *dummy)
400 {
401 	struct smbios_cru64_info *smbios_cru64_ptr;
402 	unsigned long cru_physical_address;
403 
404 	if (dm->type == SMBIOS_CRU64_INFORMATION) {
405 		smbios_cru64_ptr = (struct smbios_cru64_info *) dm;
406 		if (smbios_cru64_ptr->signature == CRU_BIOS_SIGNATURE_VALUE) {
407 			cru_physical_address =
408 				smbios_cru64_ptr->physical_address +
409 				smbios_cru64_ptr->double_offset;
410 			cru_rom_addr = ioremap(cru_physical_address,
411 				smbios_cru64_ptr->double_length);
412 			set_memory_x((unsigned long)cru_rom_addr & PAGE_MASK,
413 				smbios_cru64_ptr->double_length >> PAGE_SHIFT);
414 		}
415 	}
416 }
417 
418 static int detect_cru_service(void)
419 {
420 	cru_rom_addr = NULL;
421 
422 	dmi_walk(dmi_find_cru, NULL);
423 
424 	/* if cru_rom_addr has been set then we found a CRU service */
425 	return ((cru_rom_addr != NULL) ? 0 : -ENODEV);
426 }
427 /* ------------------------------------------------------------------------- */
428 #endif /* CONFIG_X86_64 */
429 #endif /* CONFIG_HPWDT_NMI_DECODING */
430 
431 /*
432  *	Watchdog operations
433  */
434 static void hpwdt_start(void)
435 {
436 	reload = SECS_TO_TICKS(soft_margin);
437 	iowrite16(reload, hpwdt_timer_reg);
438 	iowrite8(0x85, hpwdt_timer_con);
439 }
440 
441 static void hpwdt_stop(void)
442 {
443 	unsigned long data;
444 
445 	data = ioread8(hpwdt_timer_con);
446 	data &= 0xFE;
447 	iowrite8(data, hpwdt_timer_con);
448 }
449 
450 static void hpwdt_ping(void)
451 {
452 	iowrite16(reload, hpwdt_timer_reg);
453 }
454 
455 static int hpwdt_change_timer(int new_margin)
456 {
457 	if (new_margin < 1 || new_margin > HPWDT_MAX_TIMER) {
458 		pr_warn("New value passed in is invalid: %d seconds\n",
459 			new_margin);
460 		return -EINVAL;
461 	}
462 
463 	soft_margin = new_margin;
464 	pr_debug("New timer passed in is %d seconds\n", new_margin);
465 	reload = SECS_TO_TICKS(soft_margin);
466 
467 	return 0;
468 }
469 
470 static int hpwdt_time_left(void)
471 {
472 	return TICKS_TO_SECS(ioread16(hpwdt_timer_reg));
473 }
474 
475 #ifdef CONFIG_HPWDT_NMI_DECODING
476 /*
477  *	NMI Handler
478  */
479 static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
480 {
481 	unsigned long rom_pl;
482 	static int die_nmi_called;
483 
484 	if (!hpwdt_nmi_decoding)
485 		goto out;
486 
487 	spin_lock_irqsave(&rom_lock, rom_pl);
488 	if (!die_nmi_called && !is_icru && !is_uefi)
489 		asminline_call(&cmn_regs, cru_rom_addr);
490 	die_nmi_called = 1;
491 	spin_unlock_irqrestore(&rom_lock, rom_pl);
492 
493 	if (allow_kdump)
494 		hpwdt_stop();
495 
496 	if (!is_icru && !is_uefi) {
497 		if (cmn_regs.u1.ral == 0) {
498 			panic("An NMI occurred, "
499 				"but unable to determine source.\n");
500 		}
501 	}
502 	panic("An NMI occurred, please see the Integrated "
503 		"Management Log for details.\n");
504 
505 out:
506 	return NMI_DONE;
507 }
508 #endif /* CONFIG_HPWDT_NMI_DECODING */
509 
510 /*
511  *	/dev/watchdog handling
512  */
513 static int hpwdt_open(struct inode *inode, struct file *file)
514 {
515 	/* /dev/watchdog can only be opened once */
516 	if (test_and_set_bit(0, &hpwdt_is_open))
517 		return -EBUSY;
518 
519 	/* Start the watchdog */
520 	hpwdt_start();
521 	hpwdt_ping();
522 
523 	return nonseekable_open(inode, file);
524 }
525 
526 static int hpwdt_release(struct inode *inode, struct file *file)
527 {
528 	/* Stop the watchdog */
529 	if (expect_release == 42) {
530 		hpwdt_stop();
531 	} else {
532 		pr_crit("Unexpected close, not stopping watchdog!\n");
533 		hpwdt_ping();
534 	}
535 
536 	expect_release = 0;
537 
538 	/* /dev/watchdog is being closed, make sure it can be re-opened */
539 	clear_bit(0, &hpwdt_is_open);
540 
541 	return 0;
542 }
543 
544 static ssize_t hpwdt_write(struct file *file, const char __user *data,
545 	size_t len, loff_t *ppos)
546 {
547 	/* See if we got the magic character 'V' and reload the timer */
548 	if (len) {
549 		if (!nowayout) {
550 			size_t i;
551 
552 			/* note: just in case someone wrote the magic character
553 			 * five months ago... */
554 			expect_release = 0;
555 
556 			/* scan to see whether or not we got the magic char. */
557 			for (i = 0; i != len; i++) {
558 				char c;
559 				if (get_user(c, data + i))
560 					return -EFAULT;
561 				if (c == 'V')
562 					expect_release = 42;
563 			}
564 		}
565 
566 		/* someone wrote to us, we should reload the timer */
567 		hpwdt_ping();
568 	}
569 
570 	return len;
571 }
572 
573 static const struct watchdog_info ident = {
574 	.options = WDIOF_SETTIMEOUT |
575 		   WDIOF_KEEPALIVEPING |
576 		   WDIOF_MAGICCLOSE,
577 	.identity = "HP iLO2+ HW Watchdog Timer",
578 };
579 
580 static long hpwdt_ioctl(struct file *file, unsigned int cmd,
581 	unsigned long arg)
582 {
583 	void __user *argp = (void __user *)arg;
584 	int __user *p = argp;
585 	int new_margin;
586 	int ret = -ENOTTY;
587 
588 	switch (cmd) {
589 	case WDIOC_GETSUPPORT:
590 		ret = 0;
591 		if (copy_to_user(argp, &ident, sizeof(ident)))
592 			ret = -EFAULT;
593 		break;
594 
595 	case WDIOC_GETSTATUS:
596 	case WDIOC_GETBOOTSTATUS:
597 		ret = put_user(0, p);
598 		break;
599 
600 	case WDIOC_KEEPALIVE:
601 		hpwdt_ping();
602 		ret = 0;
603 		break;
604 
605 	case WDIOC_SETTIMEOUT:
606 		ret = get_user(new_margin, p);
607 		if (ret)
608 			break;
609 
610 		ret = hpwdt_change_timer(new_margin);
611 		if (ret)
612 			break;
613 
614 		hpwdt_ping();
615 		/* Fall */
616 	case WDIOC_GETTIMEOUT:
617 		ret = put_user(soft_margin, p);
618 		break;
619 
620 	case WDIOC_GETTIMELEFT:
621 		ret = put_user(hpwdt_time_left(), p);
622 		break;
623 	}
624 	return ret;
625 }
626 
627 /*
628  *	Kernel interfaces
629  */
630 static const struct file_operations hpwdt_fops = {
631 	.owner = THIS_MODULE,
632 	.llseek = no_llseek,
633 	.write = hpwdt_write,
634 	.unlocked_ioctl = hpwdt_ioctl,
635 	.open = hpwdt_open,
636 	.release = hpwdt_release,
637 };
638 
639 static struct miscdevice hpwdt_miscdev = {
640 	.minor = WATCHDOG_MINOR,
641 	.name = "watchdog",
642 	.fops = &hpwdt_fops,
643 };
644 
645 /*
646  *	Init & Exit
647  */
648 
649 #ifdef CONFIG_HPWDT_NMI_DECODING
650 #ifdef CONFIG_X86_LOCAL_APIC
651 static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
652 {
653 	/*
654 	 * If nmi_watchdog is turned off then we can turn on
655 	 * our nmi decoding capability.
656 	 */
657 	hpwdt_nmi_decoding = 1;
658 }
659 #else
660 static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
661 {
662 	dev_warn(&dev->dev, "NMI decoding is disabled. "
663 		"Your kernel does not support a NMI Watchdog.\n");
664 }
665 #endif /* CONFIG_X86_LOCAL_APIC */
666 
667 /*
668  *	dmi_find_icru
669  *
670  *	Routine Description:
671  *	This function checks whether or not we are on an iCRU-based server.
672  *	This check is independent of architecture and needs to be made for
673  *	any ProLiant system.
674  */
675 static void dmi_find_icru(const struct dmi_header *dm, void *dummy)
676 {
677 	struct smbios_proliant_info *smbios_proliant_ptr;
678 
679 	if (dm->type == SMBIOS_ICRU_INFORMATION) {
680 		smbios_proliant_ptr = (struct smbios_proliant_info *) dm;
681 		if (smbios_proliant_ptr->misc_features & 0x01)
682 			is_icru = 1;
683 		if (smbios_proliant_ptr->misc_features & 0x408)
684 			is_uefi = 1;
685 	}
686 }
687 
688 static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
689 {
690 	int retval;
691 
692 	/*
693 	 * On typical CRU-based systems we need to map that service in
694 	 * the BIOS. For 32 bit Operating Systems we need to go through
695 	 * the 32 Bit BIOS Service Directory. For 64 bit Operating
696 	 * Systems we get that service through SMBIOS.
697 	 *
698 	 * On systems that support the new iCRU service all we need to
699 	 * do is call dmi_walk to get the supported flag value and skip
700 	 * the old cru detect code.
701 	 */
702 	dmi_walk(dmi_find_icru, NULL);
703 	if (!is_icru && !is_uefi) {
704 
705 		/*
706 		* We need to map the ROM to get the CRU service.
707 		* For 32 bit Operating Systems we need to go through the 32 Bit
708 		* BIOS Service Directory
709 		* For 64 bit Operating Systems we get that service through SMBIOS.
710 		*/
711 		retval = detect_cru_service();
712 		if (retval < 0) {
713 			dev_warn(&dev->dev,
714 				"Unable to detect the %d Bit CRU Service.\n",
715 				HPWDT_ARCH);
716 			return retval;
717 		}
718 
719 		/*
720 		* We know this is the only CRU call we need to make so lets keep as
721 		* few instructions as possible once the NMI comes in.
722 		*/
723 		cmn_regs.u1.rah = 0x0D;
724 		cmn_regs.u1.ral = 0x02;
725 	}
726 
727 	/*
728 	 * Only one function can register for NMI_UNKNOWN
729 	 */
730 	retval = register_nmi_handler(NMI_UNKNOWN, hpwdt_pretimeout, 0, "hpwdt");
731 	if (retval)
732 		goto error;
733 	retval = register_nmi_handler(NMI_SERR, hpwdt_pretimeout, 0, "hpwdt");
734 	if (retval)
735 		goto error1;
736 	retval = register_nmi_handler(NMI_IO_CHECK, hpwdt_pretimeout, 0, "hpwdt");
737 	if (retval)
738 		goto error2;
739 
740 	dev_info(&dev->dev,
741 			"HP Watchdog Timer Driver: NMI decoding initialized"
742 			", allow kernel dump: %s (default = 0/OFF)\n",
743 			(allow_kdump == 0) ? "OFF" : "ON");
744 	return 0;
745 
746 error2:
747 	unregister_nmi_handler(NMI_SERR, "hpwdt");
748 error1:
749 	unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");
750 error:
751 	dev_warn(&dev->dev,
752 		"Unable to register a die notifier (err=%d).\n",
753 		retval);
754 	if (cru_rom_addr)
755 		iounmap(cru_rom_addr);
756 	return retval;
757 }
758 
759 static void hpwdt_exit_nmi_decoding(void)
760 {
761 	unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");
762 	unregister_nmi_handler(NMI_SERR, "hpwdt");
763 	unregister_nmi_handler(NMI_IO_CHECK, "hpwdt");
764 	if (cru_rom_addr)
765 		iounmap(cru_rom_addr);
766 }
767 #else /* !CONFIG_HPWDT_NMI_DECODING */
768 static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
769 {
770 }
771 
772 static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
773 {
774 	return 0;
775 }
776 
777 static void hpwdt_exit_nmi_decoding(void)
778 {
779 }
780 #endif /* CONFIG_HPWDT_NMI_DECODING */
781 
782 static int hpwdt_init_one(struct pci_dev *dev,
783 					const struct pci_device_id *ent)
784 {
785 	int retval;
786 
787 	/*
788 	 * Check if we can do NMI decoding or not
789 	 */
790 	hpwdt_check_nmi_decoding(dev);
791 
792 	/*
793 	 * First let's find out if we are on an iLO2+ server. We will
794 	 * not run on a legacy ASM box.
795 	 * So we only support the G5 ProLiant servers and higher.
796 	 */
797 	if (dev->subsystem_vendor != PCI_VENDOR_ID_HP) {
798 		dev_warn(&dev->dev,
799 			"This server does not have an iLO2+ ASIC.\n");
800 		return -ENODEV;
801 	}
802 
803 	if (pci_enable_device(dev)) {
804 		dev_warn(&dev->dev,
805 			"Not possible to enable PCI Device: 0x%x:0x%x.\n",
806 			ent->vendor, ent->device);
807 		return -ENODEV;
808 	}
809 
810 	pci_mem_addr = pci_iomap(dev, 1, 0x80);
811 	if (!pci_mem_addr) {
812 		dev_warn(&dev->dev,
813 			"Unable to detect the iLO2+ server memory.\n");
814 		retval = -ENOMEM;
815 		goto error_pci_iomap;
816 	}
817 	hpwdt_timer_reg = pci_mem_addr + 0x70;
818 	hpwdt_timer_con = pci_mem_addr + 0x72;
819 
820 	/* Make sure that timer is disabled until /dev/watchdog is opened */
821 	hpwdt_stop();
822 
823 	/* Make sure that we have a valid soft_margin */
824 	if (hpwdt_change_timer(soft_margin))
825 		hpwdt_change_timer(DEFAULT_MARGIN);
826 
827 	/* Initialize NMI Decoding functionality */
828 	retval = hpwdt_init_nmi_decoding(dev);
829 	if (retval != 0)
830 		goto error_init_nmi_decoding;
831 
832 	retval = misc_register(&hpwdt_miscdev);
833 	if (retval < 0) {
834 		dev_warn(&dev->dev,
835 			"Unable to register miscdev on minor=%d (err=%d).\n",
836 			WATCHDOG_MINOR, retval);
837 		goto error_misc_register;
838 	}
839 
840 	dev_info(&dev->dev, "HP Watchdog Timer Driver: %s"
841 			", timer margin: %d seconds (nowayout=%d).\n",
842 			HPWDT_VERSION, soft_margin, nowayout);
843 	return 0;
844 
845 error_misc_register:
846 	hpwdt_exit_nmi_decoding();
847 error_init_nmi_decoding:
848 	pci_iounmap(dev, pci_mem_addr);
849 error_pci_iomap:
850 	pci_disable_device(dev);
851 	return retval;
852 }
853 
854 static void hpwdt_exit(struct pci_dev *dev)
855 {
856 	if (!nowayout)
857 		hpwdt_stop();
858 
859 	misc_deregister(&hpwdt_miscdev);
860 	hpwdt_exit_nmi_decoding();
861 	pci_iounmap(dev, pci_mem_addr);
862 	pci_disable_device(dev);
863 }
864 
865 static struct pci_driver hpwdt_driver = {
866 	.name = "hpwdt",
867 	.id_table = hpwdt_devices,
868 	.probe = hpwdt_init_one,
869 	.remove = hpwdt_exit,
870 };
871 
872 MODULE_AUTHOR("Tom Mingarelli");
873 MODULE_DESCRIPTION("hp watchdog driver");
874 MODULE_LICENSE("GPL");
875 MODULE_VERSION(HPWDT_VERSION);
876 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
877 
878 module_param(soft_margin, int, 0);
879 MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
880 
881 module_param(nowayout, bool, 0);
882 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
883 		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
884 
885 #ifdef CONFIG_HPWDT_NMI_DECODING
886 module_param(allow_kdump, int, 0);
887 MODULE_PARM_DESC(allow_kdump, "Start a kernel dump after NMI occurs");
888 #endif /* !CONFIG_HPWDT_NMI_DECODING */
889 
890 module_pci_driver(hpwdt_driver);
891