xref: /linux/drivers/watchdog/hpwdt.c (revision a6b088875b5cfc2be95242826f31523214c083a7)
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\t"
166     ".globl asminline_call	    \n"
167     "asminline_call:                \n\t"
168     "pushl       %ebp               \n\t"
169     "movl        %esp, %ebp         \n\t"
170     "pusha                          \n\t"
171     "pushf                          \n\t"
172     "push        %es                \n\t"
173     "push        %ds                \n\t"
174     "pop         %es                \n\t"
175     "movl        8(%ebp),%eax       \n\t"
176     "movl        4(%eax),%ebx       \n\t"
177     "movl        8(%eax),%ecx       \n\t"
178     "movl        12(%eax),%edx      \n\t"
179     "movl        16(%eax),%esi      \n\t"
180     "movl        20(%eax),%edi      \n\t"
181     "movl        (%eax),%eax        \n\t"
182     "push        %cs                \n\t"
183     "call        *12(%ebp)          \n\t"
184     "pushf                          \n\t"
185     "pushl       %eax               \n\t"
186     "movl        8(%ebp),%eax       \n\t"
187     "movl        %ebx,4(%eax)       \n\t"
188     "movl        %ecx,8(%eax)       \n\t"
189     "movl        %edx,12(%eax)      \n\t"
190     "movl        %esi,16(%eax)      \n\t"
191     "movl        %edi,20(%eax)      \n\t"
192     "movw        %ds,24(%eax)       \n\t"
193     "movw        %es,26(%eax)       \n\t"
194     "popl        %ebx               \n\t"
195     "movl        %ebx,(%eax)        \n\t"
196     "popl        %ebx               \n\t"
197     "movl        %ebx,28(%eax)      \n\t"
198     "pop         %es                \n\t"
199     "popf                           \n\t"
200     "popa                           \n\t"
201     "leave                          \n\t"
202     "ret                            \n\t"
203     ".previous");
204 
205 
206 /*
207  *	cru_detect
208  *
209  *	Routine Description:
210  *	This function uses the 32-bit BIOS Service Directory record to
211  *	search for a $CRU record.
212  *
213  *	Return Value:
214  *	0        :  SUCCESS
215  *	<0       :  FAILURE
216  */
217 static int cru_detect(unsigned long map_entry,
218 	unsigned long map_offset)
219 {
220 	void *bios32_map;
221 	unsigned long *bios32_entrypoint;
222 	unsigned long cru_physical_address;
223 	unsigned long cru_length;
224 	unsigned long physical_bios_base = 0;
225 	unsigned long physical_bios_offset = 0;
226 	int retval = -ENODEV;
227 
228 	bios32_map = ioremap(map_entry, (2 * PAGE_SIZE));
229 
230 	if (bios32_map == NULL)
231 		return -ENODEV;
232 
233 	bios32_entrypoint = bios32_map + map_offset;
234 
235 	cmn_regs.u1.reax = CRU_BIOS_SIGNATURE_VALUE;
236 
237 	set_memory_x((unsigned long)bios32_map, 2);
238 	asminline_call(&cmn_regs, bios32_entrypoint);
239 
240 	if (cmn_regs.u1.ral != 0) {
241 		pr_warn("Call succeeded but with an error: 0x%x\n",
242 			cmn_regs.u1.ral);
243 	} else {
244 		physical_bios_base = cmn_regs.u2.rebx;
245 		physical_bios_offset = cmn_regs.u4.redx;
246 		cru_length = cmn_regs.u3.recx;
247 		cru_physical_address =
248 			physical_bios_base + physical_bios_offset;
249 
250 		/* If the values look OK, then map it in. */
251 		if ((physical_bios_base + physical_bios_offset)) {
252 			cru_rom_addr =
253 				ioremap(cru_physical_address, cru_length);
254 			if (cru_rom_addr) {
255 				set_memory_x((unsigned long)cru_rom_addr & PAGE_MASK,
256 					(cru_length + PAGE_SIZE - 1) >> PAGE_SHIFT);
257 				retval = 0;
258 			}
259 		}
260 
261 		pr_debug("CRU Base Address:   0x%lx\n", physical_bios_base);
262 		pr_debug("CRU Offset Address: 0x%lx\n", physical_bios_offset);
263 		pr_debug("CRU Length:         0x%lx\n", cru_length);
264 		pr_debug("CRU Mapped Address: %p\n", &cru_rom_addr);
265 	}
266 	iounmap(bios32_map);
267 	return retval;
268 }
269 
270 /*
271  *	bios_checksum
272  */
273 static int bios_checksum(const char __iomem *ptr, int len)
274 {
275 	char sum = 0;
276 	int i;
277 
278 	/*
279 	 * calculate checksum of size bytes. This should add up
280 	 * to zero if we have a valid header.
281 	 */
282 	for (i = 0; i < len; i++)
283 		sum += ptr[i];
284 
285 	return ((sum == 0) && (len > 0));
286 }
287 
288 /*
289  *	bios32_present
290  *
291  *	Routine Description:
292  *	This function finds the 32-bit BIOS Service Directory
293  *
294  *	Return Value:
295  *	0        :  SUCCESS
296  *	<0       :  FAILURE
297  */
298 static int bios32_present(const char __iomem *p)
299 {
300 	struct bios32_service_dir *bios_32_ptr;
301 	int length;
302 	unsigned long map_entry, map_offset;
303 
304 	bios_32_ptr = (struct bios32_service_dir *) p;
305 
306 	/*
307 	 * Search for signature by checking equal to the swizzled value
308 	 * instead of calling another routine to perform a strcmp.
309 	 */
310 	if (bios_32_ptr->signature == PCI_BIOS32_SD_VALUE) {
311 		length = bios_32_ptr->length * PCI_BIOS32_PARAGRAPH_LEN;
312 		if (bios_checksum(p, length)) {
313 			/*
314 			 * According to the spec, we're looking for the
315 			 * first 4KB-aligned address below the entrypoint
316 			 * listed in the header. The Service Directory code
317 			 * is guaranteed to occupy no more than 2 4KB pages.
318 			 */
319 			map_entry = bios_32_ptr->entry_point & ~(PAGE_SIZE - 1);
320 			map_offset = bios_32_ptr->entry_point - map_entry;
321 
322 			return cru_detect(map_entry, map_offset);
323 		}
324 	}
325 	return -ENODEV;
326 }
327 
328 static int detect_cru_service(void)
329 {
330 	char __iomem *p, *q;
331 	int rc = -1;
332 
333 	/*
334 	 * Search from 0x0f0000 through 0x0fffff, inclusive.
335 	 */
336 	p = ioremap(PCI_ROM_BASE1, ROM_SIZE);
337 	if (p == NULL)
338 		return -ENOMEM;
339 
340 	for (q = p; q < p + ROM_SIZE; q += 16) {
341 		rc = bios32_present(q);
342 		if (!rc)
343 			break;
344 	}
345 	iounmap(p);
346 	return rc;
347 }
348 /* ------------------------------------------------------------------------- */
349 #endif /* CONFIG_X86_32 */
350 #ifdef CONFIG_X86_64
351 /* --64 Bit Bios------------------------------------------------------------ */
352 
353 #define HPWDT_ARCH	64
354 
355 asm(".text                      \n\t"
356     ".align 4                   \n\t"
357     ".globl asminline_call	\n"
358     "asminline_call:            \n\t"
359     "pushq      %rbp            \n\t"
360     "movq       %rsp, %rbp      \n\t"
361     "pushq      %rax            \n\t"
362     "pushq      %rbx            \n\t"
363     "pushq      %rdx            \n\t"
364     "pushq      %r12            \n\t"
365     "pushq      %r9             \n\t"
366     "movq       %rsi, %r12      \n\t"
367     "movq       %rdi, %r9       \n\t"
368     "movl       4(%r9),%ebx     \n\t"
369     "movl       8(%r9),%ecx     \n\t"
370     "movl       12(%r9),%edx    \n\t"
371     "movl       16(%r9),%esi    \n\t"
372     "movl       20(%r9),%edi    \n\t"
373     "movl       (%r9),%eax      \n\t"
374     "call       *%r12           \n\t"
375     "pushfq                     \n\t"
376     "popq        %r12           \n\t"
377     "movl       %eax, (%r9)     \n\t"
378     "movl       %ebx, 4(%r9)    \n\t"
379     "movl       %ecx, 8(%r9)    \n\t"
380     "movl       %edx, 12(%r9)   \n\t"
381     "movl       %esi, 16(%r9)   \n\t"
382     "movl       %edi, 20(%r9)   \n\t"
383     "movq       %r12, %rax      \n\t"
384     "movl       %eax, 28(%r9)   \n\t"
385     "popq       %r9             \n\t"
386     "popq       %r12            \n\t"
387     "popq       %rdx            \n\t"
388     "popq       %rbx            \n\t"
389     "popq       %rax            \n\t"
390     "leave                      \n\t"
391     "ret                        \n\t"
392     ".previous");
393 
394 /*
395  *	dmi_find_cru
396  *
397  *	Routine Description:
398  *	This function checks whether or not a SMBIOS/DMI record is
399  *	the 64bit CRU info or not
400  */
401 static void dmi_find_cru(const struct dmi_header *dm, void *dummy)
402 {
403 	struct smbios_cru64_info *smbios_cru64_ptr;
404 	unsigned long cru_physical_address;
405 
406 	if (dm->type == SMBIOS_CRU64_INFORMATION) {
407 		smbios_cru64_ptr = (struct smbios_cru64_info *) dm;
408 		if (smbios_cru64_ptr->signature == CRU_BIOS_SIGNATURE_VALUE) {
409 			cru_physical_address =
410 				smbios_cru64_ptr->physical_address +
411 				smbios_cru64_ptr->double_offset;
412 			cru_rom_addr = ioremap(cru_physical_address,
413 				smbios_cru64_ptr->double_length);
414 			set_memory_x((unsigned long)cru_rom_addr & PAGE_MASK,
415 				smbios_cru64_ptr->double_length >> PAGE_SHIFT);
416 		}
417 	}
418 }
419 
420 static int detect_cru_service(void)
421 {
422 	cru_rom_addr = NULL;
423 
424 	dmi_walk(dmi_find_cru, NULL);
425 
426 	/* if cru_rom_addr has been set then we found a CRU service */
427 	return ((cru_rom_addr != NULL) ? 0 : -ENODEV);
428 }
429 /* ------------------------------------------------------------------------- */
430 #endif /* CONFIG_X86_64 */
431 #endif /* CONFIG_HPWDT_NMI_DECODING */
432 
433 /*
434  *	Watchdog operations
435  */
436 static void hpwdt_start(void)
437 {
438 	reload = SECS_TO_TICKS(soft_margin);
439 	iowrite16(reload, hpwdt_timer_reg);
440 	iowrite8(0x85, hpwdt_timer_con);
441 }
442 
443 static void hpwdt_stop(void)
444 {
445 	unsigned long data;
446 
447 	data = ioread8(hpwdt_timer_con);
448 	data &= 0xFE;
449 	iowrite8(data, hpwdt_timer_con);
450 }
451 
452 static void hpwdt_ping(void)
453 {
454 	iowrite16(reload, hpwdt_timer_reg);
455 }
456 
457 static int hpwdt_change_timer(int new_margin)
458 {
459 	if (new_margin < 1 || new_margin > HPWDT_MAX_TIMER) {
460 		pr_warn("New value passed in is invalid: %d seconds\n",
461 			new_margin);
462 		return -EINVAL;
463 	}
464 
465 	soft_margin = new_margin;
466 	pr_debug("New timer passed in is %d seconds\n", new_margin);
467 	reload = SECS_TO_TICKS(soft_margin);
468 
469 	return 0;
470 }
471 
472 static int hpwdt_time_left(void)
473 {
474 	return TICKS_TO_SECS(ioread16(hpwdt_timer_reg));
475 }
476 
477 #ifdef CONFIG_HPWDT_NMI_DECODING
478 /*
479  *	NMI Handler
480  */
481 static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
482 {
483 	unsigned long rom_pl;
484 	static int die_nmi_called;
485 
486 	if (!hpwdt_nmi_decoding)
487 		goto out;
488 
489 	spin_lock_irqsave(&rom_lock, rom_pl);
490 	if (!die_nmi_called && !is_icru && !is_uefi)
491 		asminline_call(&cmn_regs, cru_rom_addr);
492 	die_nmi_called = 1;
493 	spin_unlock_irqrestore(&rom_lock, rom_pl);
494 
495 	if (allow_kdump)
496 		hpwdt_stop();
497 
498 	if (!is_icru && !is_uefi) {
499 		if (cmn_regs.u1.ral == 0) {
500 			panic("An NMI occurred, "
501 				"but unable to determine source.\n");
502 		}
503 	}
504 	panic("An NMI occurred, please see the Integrated "
505 		"Management Log for details.\n");
506 
507 out:
508 	return NMI_DONE;
509 }
510 #endif /* CONFIG_HPWDT_NMI_DECODING */
511 
512 /*
513  *	/dev/watchdog handling
514  */
515 static int hpwdt_open(struct inode *inode, struct file *file)
516 {
517 	/* /dev/watchdog can only be opened once */
518 	if (test_and_set_bit(0, &hpwdt_is_open))
519 		return -EBUSY;
520 
521 	/* Start the watchdog */
522 	hpwdt_start();
523 	hpwdt_ping();
524 
525 	return nonseekable_open(inode, file);
526 }
527 
528 static int hpwdt_release(struct inode *inode, struct file *file)
529 {
530 	/* Stop the watchdog */
531 	if (expect_release == 42) {
532 		hpwdt_stop();
533 	} else {
534 		pr_crit("Unexpected close, not stopping watchdog!\n");
535 		hpwdt_ping();
536 	}
537 
538 	expect_release = 0;
539 
540 	/* /dev/watchdog is being closed, make sure it can be re-opened */
541 	clear_bit(0, &hpwdt_is_open);
542 
543 	return 0;
544 }
545 
546 static ssize_t hpwdt_write(struct file *file, const char __user *data,
547 	size_t len, loff_t *ppos)
548 {
549 	/* See if we got the magic character 'V' and reload the timer */
550 	if (len) {
551 		if (!nowayout) {
552 			size_t i;
553 
554 			/* note: just in case someone wrote the magic character
555 			 * five months ago... */
556 			expect_release = 0;
557 
558 			/* scan to see whether or not we got the magic char. */
559 			for (i = 0; i != len; i++) {
560 				char c;
561 				if (get_user(c, data + i))
562 					return -EFAULT;
563 				if (c == 'V')
564 					expect_release = 42;
565 			}
566 		}
567 
568 		/* someone wrote to us, we should reload the timer */
569 		hpwdt_ping();
570 	}
571 
572 	return len;
573 }
574 
575 static const struct watchdog_info ident = {
576 	.options = WDIOF_SETTIMEOUT |
577 		   WDIOF_KEEPALIVEPING |
578 		   WDIOF_MAGICCLOSE,
579 	.identity = "HP iLO2+ HW Watchdog Timer",
580 };
581 
582 static long hpwdt_ioctl(struct file *file, unsigned int cmd,
583 	unsigned long arg)
584 {
585 	void __user *argp = (void __user *)arg;
586 	int __user *p = argp;
587 	int new_margin;
588 	int ret = -ENOTTY;
589 
590 	switch (cmd) {
591 	case WDIOC_GETSUPPORT:
592 		ret = 0;
593 		if (copy_to_user(argp, &ident, sizeof(ident)))
594 			ret = -EFAULT;
595 		break;
596 
597 	case WDIOC_GETSTATUS:
598 	case WDIOC_GETBOOTSTATUS:
599 		ret = put_user(0, p);
600 		break;
601 
602 	case WDIOC_KEEPALIVE:
603 		hpwdt_ping();
604 		ret = 0;
605 		break;
606 
607 	case WDIOC_SETTIMEOUT:
608 		ret = get_user(new_margin, p);
609 		if (ret)
610 			break;
611 
612 		ret = hpwdt_change_timer(new_margin);
613 		if (ret)
614 			break;
615 
616 		hpwdt_ping();
617 		/* Fall */
618 	case WDIOC_GETTIMEOUT:
619 		ret = put_user(soft_margin, p);
620 		break;
621 
622 	case WDIOC_GETTIMELEFT:
623 		ret = put_user(hpwdt_time_left(), p);
624 		break;
625 	}
626 	return ret;
627 }
628 
629 /*
630  *	Kernel interfaces
631  */
632 static const struct file_operations hpwdt_fops = {
633 	.owner = THIS_MODULE,
634 	.llseek = no_llseek,
635 	.write = hpwdt_write,
636 	.unlocked_ioctl = hpwdt_ioctl,
637 	.open = hpwdt_open,
638 	.release = hpwdt_release,
639 };
640 
641 static struct miscdevice hpwdt_miscdev = {
642 	.minor = WATCHDOG_MINOR,
643 	.name = "watchdog",
644 	.fops = &hpwdt_fops,
645 };
646 
647 /*
648  *	Init & Exit
649  */
650 
651 #ifdef CONFIG_HPWDT_NMI_DECODING
652 #ifdef CONFIG_X86_LOCAL_APIC
653 static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
654 {
655 	/*
656 	 * If nmi_watchdog is turned off then we can turn on
657 	 * our nmi decoding capability.
658 	 */
659 	hpwdt_nmi_decoding = 1;
660 }
661 #else
662 static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
663 {
664 	dev_warn(&dev->dev, "NMI decoding is disabled. "
665 		"Your kernel does not support a NMI Watchdog.\n");
666 }
667 #endif /* CONFIG_X86_LOCAL_APIC */
668 
669 /*
670  *	dmi_find_icru
671  *
672  *	Routine Description:
673  *	This function checks whether or not we are on an iCRU-based server.
674  *	This check is independent of architecture and needs to be made for
675  *	any ProLiant system.
676  */
677 static void dmi_find_icru(const struct dmi_header *dm, void *dummy)
678 {
679 	struct smbios_proliant_info *smbios_proliant_ptr;
680 
681 	if (dm->type == SMBIOS_ICRU_INFORMATION) {
682 		smbios_proliant_ptr = (struct smbios_proliant_info *) dm;
683 		if (smbios_proliant_ptr->misc_features & 0x01)
684 			is_icru = 1;
685 		if (smbios_proliant_ptr->misc_features & 0x408)
686 			is_uefi = 1;
687 	}
688 }
689 
690 static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
691 {
692 	int retval;
693 
694 	/*
695 	 * On typical CRU-based systems we need to map that service in
696 	 * the BIOS. For 32 bit Operating Systems we need to go through
697 	 * the 32 Bit BIOS Service Directory. For 64 bit Operating
698 	 * Systems we get that service through SMBIOS.
699 	 *
700 	 * On systems that support the new iCRU service all we need to
701 	 * do is call dmi_walk to get the supported flag value and skip
702 	 * the old cru detect code.
703 	 */
704 	dmi_walk(dmi_find_icru, NULL);
705 	if (!is_icru && !is_uefi) {
706 
707 		/*
708 		* We need to map the ROM to get the CRU service.
709 		* For 32 bit Operating Systems we need to go through the 32 Bit
710 		* BIOS Service Directory
711 		* For 64 bit Operating Systems we get that service through SMBIOS.
712 		*/
713 		retval = detect_cru_service();
714 		if (retval < 0) {
715 			dev_warn(&dev->dev,
716 				"Unable to detect the %d Bit CRU Service.\n",
717 				HPWDT_ARCH);
718 			return retval;
719 		}
720 
721 		/*
722 		* We know this is the only CRU call we need to make so lets keep as
723 		* few instructions as possible once the NMI comes in.
724 		*/
725 		cmn_regs.u1.rah = 0x0D;
726 		cmn_regs.u1.ral = 0x02;
727 	}
728 
729 	/*
730 	 * Only one function can register for NMI_UNKNOWN
731 	 */
732 	retval = register_nmi_handler(NMI_UNKNOWN, hpwdt_pretimeout, 0, "hpwdt");
733 	if (retval)
734 		goto error;
735 	retval = register_nmi_handler(NMI_SERR, hpwdt_pretimeout, 0, "hpwdt");
736 	if (retval)
737 		goto error1;
738 	retval = register_nmi_handler(NMI_IO_CHECK, hpwdt_pretimeout, 0, "hpwdt");
739 	if (retval)
740 		goto error2;
741 
742 	dev_info(&dev->dev,
743 			"HP Watchdog Timer Driver: NMI decoding initialized"
744 			", allow kernel dump: %s (default = 0/OFF)\n",
745 			(allow_kdump == 0) ? "OFF" : "ON");
746 	return 0;
747 
748 error2:
749 	unregister_nmi_handler(NMI_SERR, "hpwdt");
750 error1:
751 	unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");
752 error:
753 	dev_warn(&dev->dev,
754 		"Unable to register a die notifier (err=%d).\n",
755 		retval);
756 	if (cru_rom_addr)
757 		iounmap(cru_rom_addr);
758 	return retval;
759 }
760 
761 static void hpwdt_exit_nmi_decoding(void)
762 {
763 	unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");
764 	unregister_nmi_handler(NMI_SERR, "hpwdt");
765 	unregister_nmi_handler(NMI_IO_CHECK, "hpwdt");
766 	if (cru_rom_addr)
767 		iounmap(cru_rom_addr);
768 }
769 #else /* !CONFIG_HPWDT_NMI_DECODING */
770 static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
771 {
772 }
773 
774 static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
775 {
776 	return 0;
777 }
778 
779 static void hpwdt_exit_nmi_decoding(void)
780 {
781 }
782 #endif /* CONFIG_HPWDT_NMI_DECODING */
783 
784 static int hpwdt_init_one(struct pci_dev *dev,
785 					const struct pci_device_id *ent)
786 {
787 	int retval;
788 
789 	/*
790 	 * Check if we can do NMI decoding or not
791 	 */
792 	hpwdt_check_nmi_decoding(dev);
793 
794 	/*
795 	 * First let's find out if we are on an iLO2+ server. We will
796 	 * not run on a legacy ASM box.
797 	 * So we only support the G5 ProLiant servers and higher.
798 	 */
799 	if (dev->subsystem_vendor != PCI_VENDOR_ID_HP) {
800 		dev_warn(&dev->dev,
801 			"This server does not have an iLO2+ ASIC.\n");
802 		return -ENODEV;
803 	}
804 
805 	if (pci_enable_device(dev)) {
806 		dev_warn(&dev->dev,
807 			"Not possible to enable PCI Device: 0x%x:0x%x.\n",
808 			ent->vendor, ent->device);
809 		return -ENODEV;
810 	}
811 
812 	pci_mem_addr = pci_iomap(dev, 1, 0x80);
813 	if (!pci_mem_addr) {
814 		dev_warn(&dev->dev,
815 			"Unable to detect the iLO2+ server memory.\n");
816 		retval = -ENOMEM;
817 		goto error_pci_iomap;
818 	}
819 	hpwdt_timer_reg = pci_mem_addr + 0x70;
820 	hpwdt_timer_con = pci_mem_addr + 0x72;
821 
822 	/* Make sure that timer is disabled until /dev/watchdog is opened */
823 	hpwdt_stop();
824 
825 	/* Make sure that we have a valid soft_margin */
826 	if (hpwdt_change_timer(soft_margin))
827 		hpwdt_change_timer(DEFAULT_MARGIN);
828 
829 	/* Initialize NMI Decoding functionality */
830 	retval = hpwdt_init_nmi_decoding(dev);
831 	if (retval != 0)
832 		goto error_init_nmi_decoding;
833 
834 	retval = misc_register(&hpwdt_miscdev);
835 	if (retval < 0) {
836 		dev_warn(&dev->dev,
837 			"Unable to register miscdev on minor=%d (err=%d).\n",
838 			WATCHDOG_MINOR, retval);
839 		goto error_misc_register;
840 	}
841 
842 	dev_info(&dev->dev, "HP Watchdog Timer Driver: %s"
843 			", timer margin: %d seconds (nowayout=%d).\n",
844 			HPWDT_VERSION, soft_margin, nowayout);
845 	return 0;
846 
847 error_misc_register:
848 	hpwdt_exit_nmi_decoding();
849 error_init_nmi_decoding:
850 	pci_iounmap(dev, pci_mem_addr);
851 error_pci_iomap:
852 	pci_disable_device(dev);
853 	return retval;
854 }
855 
856 static void hpwdt_exit(struct pci_dev *dev)
857 {
858 	if (!nowayout)
859 		hpwdt_stop();
860 
861 	misc_deregister(&hpwdt_miscdev);
862 	hpwdt_exit_nmi_decoding();
863 	pci_iounmap(dev, pci_mem_addr);
864 	pci_disable_device(dev);
865 }
866 
867 static struct pci_driver hpwdt_driver = {
868 	.name = "hpwdt",
869 	.id_table = hpwdt_devices,
870 	.probe = hpwdt_init_one,
871 	.remove = hpwdt_exit,
872 };
873 
874 MODULE_AUTHOR("Tom Mingarelli");
875 MODULE_DESCRIPTION("hp watchdog driver");
876 MODULE_LICENSE("GPL");
877 MODULE_VERSION(HPWDT_VERSION);
878 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
879 
880 module_param(soft_margin, int, 0);
881 MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
882 
883 module_param(nowayout, bool, 0);
884 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
885 		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
886 
887 #ifdef CONFIG_HPWDT_NMI_DECODING
888 module_param(allow_kdump, int, 0);
889 MODULE_PARM_DESC(allow_kdump, "Start a kernel dump after NMI occurs");
890 #endif /* !CONFIG_HPWDT_NMI_DECODING */
891 
892 module_pci_driver(hpwdt_driver);
893