xref: /openbmc/linux/drivers/watchdog/hpwdt.c (revision eb3fcf00)
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/io.h>
21 #include <linux/bitops.h>
22 #include <linux/kernel.h>
23 #include <linux/miscdevice.h>
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/pci.h>
27 #include <linux/pci_ids.h>
28 #include <linux/types.h>
29 #include <linux/uaccess.h>
30 #include <linux/watchdog.h>
31 #ifdef CONFIG_HPWDT_NMI_DECODING
32 #include <linux/dmi.h>
33 #include <linux/spinlock.h>
34 #include <linux/nmi.h>
35 #include <linux/kdebug.h>
36 #include <linux/notifier.h>
37 #include <asm/cacheflush.h>
38 #endif /* CONFIG_HPWDT_NMI_DECODING */
39 #include <asm/nmi.h>
40 
41 #define HPWDT_VERSION			"1.3.3"
42 #define SECS_TO_TICKS(secs)		((secs) * 1000 / 128)
43 #define TICKS_TO_SECS(ticks)		((ticks) * 128 / 1000)
44 #define HPWDT_MAX_TIMER			TICKS_TO_SECS(65535)
45 #define DEFAULT_MARGIN			30
46 
47 static unsigned int soft_margin = DEFAULT_MARGIN;	/* in seconds */
48 static unsigned int reload;			/* the computed soft_margin */
49 static bool nowayout = WATCHDOG_NOWAYOUT;
50 static char expect_release;
51 static unsigned long hpwdt_is_open;
52 
53 static void __iomem *pci_mem_addr;		/* the PCI-memory address */
54 static unsigned long __iomem *hpwdt_timer_reg;
55 static unsigned long __iomem *hpwdt_timer_con;
56 
57 static const struct pci_device_id hpwdt_devices[] = {
58 	{ PCI_DEVICE(PCI_VENDOR_ID_COMPAQ, 0xB203) },	/* iLO2 */
59 	{ PCI_DEVICE(PCI_VENDOR_ID_HP, 0x3306) },	/* iLO3 */
60 	{0},			/* terminate list */
61 };
62 MODULE_DEVICE_TABLE(pci, hpwdt_devices);
63 
64 #ifdef CONFIG_HPWDT_NMI_DECODING
65 #define PCI_BIOS32_SD_VALUE		0x5F32335F	/* "_32_" */
66 #define CRU_BIOS_SIGNATURE_VALUE	0x55524324
67 #define PCI_BIOS32_PARAGRAPH_LEN	16
68 #define PCI_ROM_BASE1			0x000F0000
69 #define ROM_SIZE			0x10000
70 
71 struct bios32_service_dir {
72 	u32 signature;
73 	u32 entry_point;
74 	u8 revision;
75 	u8 length;
76 	u8 checksum;
77 	u8 reserved[5];
78 };
79 
80 /* type 212 */
81 struct smbios_cru64_info {
82 	u8 type;
83 	u8 byte_length;
84 	u16 handle;
85 	u32 signature;
86 	u64 physical_address;
87 	u32 double_length;
88 	u32 double_offset;
89 };
90 #define SMBIOS_CRU64_INFORMATION	212
91 
92 /* type 219 */
93 struct smbios_proliant_info {
94 	u8 type;
95 	u8 byte_length;
96 	u16 handle;
97 	u32 power_features;
98 	u32 omega_features;
99 	u32 reserved;
100 	u32 misc_features;
101 };
102 #define SMBIOS_ICRU_INFORMATION		219
103 
104 
105 struct cmn_registers {
106 	union {
107 		struct {
108 			u8 ral;
109 			u8 rah;
110 			u16 rea2;
111 		};
112 		u32 reax;
113 	} u1;
114 	union {
115 		struct {
116 			u8 rbl;
117 			u8 rbh;
118 			u8 reb2l;
119 			u8 reb2h;
120 		};
121 		u32 rebx;
122 	} u2;
123 	union {
124 		struct {
125 			u8 rcl;
126 			u8 rch;
127 			u16 rec2;
128 		};
129 		u32 recx;
130 	} u3;
131 	union {
132 		struct {
133 			u8 rdl;
134 			u8 rdh;
135 			u16 red2;
136 		};
137 		u32 redx;
138 	} u4;
139 
140 	u32 resi;
141 	u32 redi;
142 	u16 rds;
143 	u16 res;
144 	u32 reflags;
145 }  __attribute__((packed));
146 
147 static unsigned int hpwdt_nmi_decoding;
148 static unsigned int allow_kdump = 1;
149 static unsigned int is_icru;
150 static unsigned int is_uefi;
151 static DEFINE_SPINLOCK(rom_lock);
152 static void *cru_rom_addr;
153 static struct cmn_registers cmn_regs;
154 
155 extern asmlinkage void asminline_call(struct cmn_registers *pi86Regs,
156 						unsigned long *pRomEntry);
157 
158 #ifdef CONFIG_X86_32
159 /* --32 Bit Bios------------------------------------------------------------ */
160 
161 #define HPWDT_ARCH	32
162 
163 asm(".text                          \n\t"
164     ".align 4                       \n\t"
165     ".globl asminline_call	    \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\t"
356     ".globl asminline_call	\n"
357     "asminline_call:            \n\t"
358     "pushq      %rbp            \n\t"
359     "movq       %rsp, %rbp      \n\t"
360     "pushq      %rax            \n\t"
361     "pushq      %rbx            \n\t"
362     "pushq      %rdx            \n\t"
363     "pushq      %r12            \n\t"
364     "pushq      %r9             \n\t"
365     "movq       %rsi, %r12      \n\t"
366     "movq       %rdi, %r9       \n\t"
367     "movl       4(%r9),%ebx     \n\t"
368     "movl       8(%r9),%ecx     \n\t"
369     "movl       12(%r9),%edx    \n\t"
370     "movl       16(%r9),%esi    \n\t"
371     "movl       20(%r9),%edi    \n\t"
372     "movl       (%r9),%eax      \n\t"
373     "call       *%r12           \n\t"
374     "pushfq                     \n\t"
375     "popq        %r12           \n\t"
376     "movl       %eax, (%r9)     \n\t"
377     "movl       %ebx, 4(%r9)    \n\t"
378     "movl       %ecx, 8(%r9)    \n\t"
379     "movl       %edx, 12(%r9)   \n\t"
380     "movl       %esi, 16(%r9)   \n\t"
381     "movl       %edi, 20(%r9)   \n\t"
382     "movq       %r12, %rax      \n\t"
383     "movl       %eax, 28(%r9)   \n\t"
384     "popq       %r9             \n\t"
385     "popq       %r12            \n\t"
386     "popq       %rdx            \n\t"
387     "popq       %rbx            \n\t"
388     "popq       %rax            \n\t"
389     "leave                      \n\t"
390     "ret                        \n\t"
391     ".previous");
392 
393 /*
394  *	dmi_find_cru
395  *
396  *	Routine Description:
397  *	This function checks whether or not a SMBIOS/DMI record is
398  *	the 64bit CRU info or not
399  */
400 static void dmi_find_cru(const struct dmi_header *dm, void *dummy)
401 {
402 	struct smbios_cru64_info *smbios_cru64_ptr;
403 	unsigned long cru_physical_address;
404 
405 	if (dm->type == SMBIOS_CRU64_INFORMATION) {
406 		smbios_cru64_ptr = (struct smbios_cru64_info *) dm;
407 		if (smbios_cru64_ptr->signature == CRU_BIOS_SIGNATURE_VALUE) {
408 			cru_physical_address =
409 				smbios_cru64_ptr->physical_address +
410 				smbios_cru64_ptr->double_offset;
411 			cru_rom_addr = ioremap(cru_physical_address,
412 				smbios_cru64_ptr->double_length);
413 			set_memory_x((unsigned long)cru_rom_addr & PAGE_MASK,
414 				smbios_cru64_ptr->double_length >> PAGE_SHIFT);
415 		}
416 	}
417 }
418 
419 static int detect_cru_service(void)
420 {
421 	cru_rom_addr = NULL;
422 
423 	dmi_walk(dmi_find_cru, NULL);
424 
425 	/* if cru_rom_addr has been set then we found a CRU service */
426 	return ((cru_rom_addr != NULL) ? 0 : -ENODEV);
427 }
428 /* ------------------------------------------------------------------------- */
429 #endif /* CONFIG_X86_64 */
430 #endif /* CONFIG_HPWDT_NMI_DECODING */
431 
432 /*
433  *	Watchdog operations
434  */
435 static void hpwdt_start(void)
436 {
437 	reload = SECS_TO_TICKS(soft_margin);
438 	iowrite16(reload, hpwdt_timer_reg);
439 	iowrite8(0x85, hpwdt_timer_con);
440 }
441 
442 static void hpwdt_stop(void)
443 {
444 	unsigned long data;
445 
446 	data = ioread8(hpwdt_timer_con);
447 	data &= 0xFE;
448 	iowrite8(data, hpwdt_timer_con);
449 }
450 
451 static void hpwdt_ping(void)
452 {
453 	iowrite16(reload, hpwdt_timer_reg);
454 }
455 
456 static int hpwdt_change_timer(int new_margin)
457 {
458 	if (new_margin < 1 || new_margin > HPWDT_MAX_TIMER) {
459 		pr_warn("New value passed in is invalid: %d seconds\n",
460 			new_margin);
461 		return -EINVAL;
462 	}
463 
464 	soft_margin = new_margin;
465 	pr_debug("New timer passed in is %d seconds\n", new_margin);
466 	reload = SECS_TO_TICKS(soft_margin);
467 
468 	return 0;
469 }
470 
471 static int hpwdt_time_left(void)
472 {
473 	return TICKS_TO_SECS(ioread16(hpwdt_timer_reg));
474 }
475 
476 #ifdef CONFIG_HPWDT_NMI_DECODING
477 /*
478  *	NMI Handler
479  */
480 static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs)
481 {
482 	unsigned long rom_pl;
483 	static int die_nmi_called;
484 
485 	if (!hpwdt_nmi_decoding)
486 		goto out;
487 
488 	spin_lock_irqsave(&rom_lock, rom_pl);
489 	if (!die_nmi_called && !is_icru && !is_uefi)
490 		asminline_call(&cmn_regs, cru_rom_addr);
491 	die_nmi_called = 1;
492 	spin_unlock_irqrestore(&rom_lock, rom_pl);
493 
494 	if (allow_kdump)
495 		hpwdt_stop();
496 
497 	if (!is_icru && !is_uefi) {
498 		if (cmn_regs.u1.ral == 0) {
499 			panic("An NMI occurred, "
500 				"but unable to determine source.\n");
501 		}
502 	}
503 	panic("An NMI occurred. Depending on your system the reason "
504 		"for the NMI is logged in any one of the following "
505 		"resources:\n"
506 		"1. Integrated Management Log (IML)\n"
507 		"2. OA Syslog\n"
508 		"3. OA Forward Progress Log\n"
509 		"4. iLO Event Log");
510 
511 out:
512 	return NMI_DONE;
513 }
514 #endif /* CONFIG_HPWDT_NMI_DECODING */
515 
516 /*
517  *	/dev/watchdog handling
518  */
519 static int hpwdt_open(struct inode *inode, struct file *file)
520 {
521 	/* /dev/watchdog can only be opened once */
522 	if (test_and_set_bit(0, &hpwdt_is_open))
523 		return -EBUSY;
524 
525 	/* Start the watchdog */
526 	hpwdt_start();
527 	hpwdt_ping();
528 
529 	return nonseekable_open(inode, file);
530 }
531 
532 static int hpwdt_release(struct inode *inode, struct file *file)
533 {
534 	/* Stop the watchdog */
535 	if (expect_release == 42) {
536 		hpwdt_stop();
537 	} else {
538 		pr_crit("Unexpected close, not stopping watchdog!\n");
539 		hpwdt_ping();
540 	}
541 
542 	expect_release = 0;
543 
544 	/* /dev/watchdog is being closed, make sure it can be re-opened */
545 	clear_bit(0, &hpwdt_is_open);
546 
547 	return 0;
548 }
549 
550 static ssize_t hpwdt_write(struct file *file, const char __user *data,
551 	size_t len, loff_t *ppos)
552 {
553 	/* See if we got the magic character 'V' and reload the timer */
554 	if (len) {
555 		if (!nowayout) {
556 			size_t i;
557 
558 			/* note: just in case someone wrote the magic character
559 			 * five months ago... */
560 			expect_release = 0;
561 
562 			/* scan to see whether or not we got the magic char. */
563 			for (i = 0; i != len; i++) {
564 				char c;
565 				if (get_user(c, data + i))
566 					return -EFAULT;
567 				if (c == 'V')
568 					expect_release = 42;
569 			}
570 		}
571 
572 		/* someone wrote to us, we should reload the timer */
573 		hpwdt_ping();
574 	}
575 
576 	return len;
577 }
578 
579 static const struct watchdog_info ident = {
580 	.options = WDIOF_SETTIMEOUT |
581 		   WDIOF_KEEPALIVEPING |
582 		   WDIOF_MAGICCLOSE,
583 	.identity = "HP iLO2+ HW Watchdog Timer",
584 };
585 
586 static long hpwdt_ioctl(struct file *file, unsigned int cmd,
587 	unsigned long arg)
588 {
589 	void __user *argp = (void __user *)arg;
590 	int __user *p = argp;
591 	int new_margin, options;
592 	int ret = -ENOTTY;
593 
594 	switch (cmd) {
595 	case WDIOC_GETSUPPORT:
596 		ret = 0;
597 		if (copy_to_user(argp, &ident, sizeof(ident)))
598 			ret = -EFAULT;
599 		break;
600 
601 	case WDIOC_GETSTATUS:
602 	case WDIOC_GETBOOTSTATUS:
603 		ret = put_user(0, p);
604 		break;
605 
606 	case WDIOC_KEEPALIVE:
607 		hpwdt_ping();
608 		ret = 0;
609 		break;
610 
611 	case WDIOC_SETOPTIONS:
612 		ret = get_user(options, p);
613 		if (ret)
614 			break;
615 
616 		if (options & WDIOS_DISABLECARD)
617 			hpwdt_stop();
618 
619 		if (options & WDIOS_ENABLECARD) {
620 			hpwdt_start();
621 			hpwdt_ping();
622 		}
623 		break;
624 
625 	case WDIOC_SETTIMEOUT:
626 		ret = get_user(new_margin, p);
627 		if (ret)
628 			break;
629 
630 		ret = hpwdt_change_timer(new_margin);
631 		if (ret)
632 			break;
633 
634 		hpwdt_ping();
635 		/* Fall */
636 	case WDIOC_GETTIMEOUT:
637 		ret = put_user(soft_margin, p);
638 		break;
639 
640 	case WDIOC_GETTIMELEFT:
641 		ret = put_user(hpwdt_time_left(), p);
642 		break;
643 	}
644 	return ret;
645 }
646 
647 /*
648  *	Kernel interfaces
649  */
650 static const struct file_operations hpwdt_fops = {
651 	.owner = THIS_MODULE,
652 	.llseek = no_llseek,
653 	.write = hpwdt_write,
654 	.unlocked_ioctl = hpwdt_ioctl,
655 	.open = hpwdt_open,
656 	.release = hpwdt_release,
657 };
658 
659 static struct miscdevice hpwdt_miscdev = {
660 	.minor = WATCHDOG_MINOR,
661 	.name = "watchdog",
662 	.fops = &hpwdt_fops,
663 };
664 
665 /*
666  *	Init & Exit
667  */
668 
669 #ifdef CONFIG_HPWDT_NMI_DECODING
670 #ifdef CONFIG_X86_LOCAL_APIC
671 static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
672 {
673 	/*
674 	 * If nmi_watchdog is turned off then we can turn on
675 	 * our nmi decoding capability.
676 	 */
677 	hpwdt_nmi_decoding = 1;
678 }
679 #else
680 static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
681 {
682 	dev_warn(&dev->dev, "NMI decoding is disabled. "
683 		"Your kernel does not support a NMI Watchdog.\n");
684 }
685 #endif /* CONFIG_X86_LOCAL_APIC */
686 
687 /*
688  *	dmi_find_icru
689  *
690  *	Routine Description:
691  *	This function checks whether or not we are on an iCRU-based server.
692  *	This check is independent of architecture and needs to be made for
693  *	any ProLiant system.
694  */
695 static void dmi_find_icru(const struct dmi_header *dm, void *dummy)
696 {
697 	struct smbios_proliant_info *smbios_proliant_ptr;
698 
699 	if (dm->type == SMBIOS_ICRU_INFORMATION) {
700 		smbios_proliant_ptr = (struct smbios_proliant_info *) dm;
701 		if (smbios_proliant_ptr->misc_features & 0x01)
702 			is_icru = 1;
703 		if (smbios_proliant_ptr->misc_features & 0x408)
704 			is_uefi = 1;
705 	}
706 }
707 
708 static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
709 {
710 	int retval;
711 
712 	/*
713 	 * On typical CRU-based systems we need to map that service in
714 	 * the BIOS. For 32 bit Operating Systems we need to go through
715 	 * the 32 Bit BIOS Service Directory. For 64 bit Operating
716 	 * Systems we get that service through SMBIOS.
717 	 *
718 	 * On systems that support the new iCRU service all we need to
719 	 * do is call dmi_walk to get the supported flag value and skip
720 	 * the old cru detect code.
721 	 */
722 	dmi_walk(dmi_find_icru, NULL);
723 	if (!is_icru && !is_uefi) {
724 
725 		/*
726 		* We need to map the ROM to get the CRU service.
727 		* For 32 bit Operating Systems we need to go through the 32 Bit
728 		* BIOS Service Directory
729 		* For 64 bit Operating Systems we get that service through SMBIOS.
730 		*/
731 		retval = detect_cru_service();
732 		if (retval < 0) {
733 			dev_warn(&dev->dev,
734 				"Unable to detect the %d Bit CRU Service.\n",
735 				HPWDT_ARCH);
736 			return retval;
737 		}
738 
739 		/*
740 		* We know this is the only CRU call we need to make so lets keep as
741 		* few instructions as possible once the NMI comes in.
742 		*/
743 		cmn_regs.u1.rah = 0x0D;
744 		cmn_regs.u1.ral = 0x02;
745 	}
746 
747 	/*
748 	 * Only one function can register for NMI_UNKNOWN
749 	 */
750 	retval = register_nmi_handler(NMI_UNKNOWN, hpwdt_pretimeout, 0, "hpwdt");
751 	if (retval)
752 		goto error;
753 	retval = register_nmi_handler(NMI_SERR, hpwdt_pretimeout, 0, "hpwdt");
754 	if (retval)
755 		goto error1;
756 	retval = register_nmi_handler(NMI_IO_CHECK, hpwdt_pretimeout, 0, "hpwdt");
757 	if (retval)
758 		goto error2;
759 
760 	dev_info(&dev->dev,
761 			"HP Watchdog Timer Driver: NMI decoding initialized"
762 			", allow kernel dump: %s (default = 1/ON)\n",
763 			(allow_kdump == 0) ? "OFF" : "ON");
764 	return 0;
765 
766 error2:
767 	unregister_nmi_handler(NMI_SERR, "hpwdt");
768 error1:
769 	unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");
770 error:
771 	dev_warn(&dev->dev,
772 		"Unable to register a die notifier (err=%d).\n",
773 		retval);
774 	if (cru_rom_addr)
775 		iounmap(cru_rom_addr);
776 	return retval;
777 }
778 
779 static void hpwdt_exit_nmi_decoding(void)
780 {
781 	unregister_nmi_handler(NMI_UNKNOWN, "hpwdt");
782 	unregister_nmi_handler(NMI_SERR, "hpwdt");
783 	unregister_nmi_handler(NMI_IO_CHECK, "hpwdt");
784 	if (cru_rom_addr)
785 		iounmap(cru_rom_addr);
786 }
787 #else /* !CONFIG_HPWDT_NMI_DECODING */
788 static void hpwdt_check_nmi_decoding(struct pci_dev *dev)
789 {
790 }
791 
792 static int hpwdt_init_nmi_decoding(struct pci_dev *dev)
793 {
794 	return 0;
795 }
796 
797 static void hpwdt_exit_nmi_decoding(void)
798 {
799 }
800 #endif /* CONFIG_HPWDT_NMI_DECODING */
801 
802 static int hpwdt_init_one(struct pci_dev *dev,
803 					const struct pci_device_id *ent)
804 {
805 	int retval;
806 
807 	/*
808 	 * Check if we can do NMI decoding or not
809 	 */
810 	hpwdt_check_nmi_decoding(dev);
811 
812 	/*
813 	 * First let's find out if we are on an iLO2+ server. We will
814 	 * not run on a legacy ASM box.
815 	 * So we only support the G5 ProLiant servers and higher.
816 	 */
817 	if (dev->subsystem_vendor != PCI_VENDOR_ID_HP) {
818 		dev_warn(&dev->dev,
819 			"This server does not have an iLO2+ ASIC.\n");
820 		return -ENODEV;
821 	}
822 
823 	/*
824 	 * Ignore all auxilary iLO devices with the following PCI ID
825 	 */
826 	if (dev->subsystem_device == 0x1979)
827 		return -ENODEV;
828 
829 	if (pci_enable_device(dev)) {
830 		dev_warn(&dev->dev,
831 			"Not possible to enable PCI Device: 0x%x:0x%x.\n",
832 			ent->vendor, ent->device);
833 		return -ENODEV;
834 	}
835 
836 	pci_mem_addr = pci_iomap(dev, 1, 0x80);
837 	if (!pci_mem_addr) {
838 		dev_warn(&dev->dev,
839 			"Unable to detect the iLO2+ server memory.\n");
840 		retval = -ENOMEM;
841 		goto error_pci_iomap;
842 	}
843 	hpwdt_timer_reg = pci_mem_addr + 0x70;
844 	hpwdt_timer_con = pci_mem_addr + 0x72;
845 
846 	/* Make sure that timer is disabled until /dev/watchdog is opened */
847 	hpwdt_stop();
848 
849 	/* Make sure that we have a valid soft_margin */
850 	if (hpwdt_change_timer(soft_margin))
851 		hpwdt_change_timer(DEFAULT_MARGIN);
852 
853 	/* Initialize NMI Decoding functionality */
854 	retval = hpwdt_init_nmi_decoding(dev);
855 	if (retval != 0)
856 		goto error_init_nmi_decoding;
857 
858 	retval = misc_register(&hpwdt_miscdev);
859 	if (retval < 0) {
860 		dev_warn(&dev->dev,
861 			"Unable to register miscdev on minor=%d (err=%d).\n",
862 			WATCHDOG_MINOR, retval);
863 		goto error_misc_register;
864 	}
865 
866 	dev_info(&dev->dev, "HP Watchdog Timer Driver: %s"
867 			", timer margin: %d seconds (nowayout=%d).\n",
868 			HPWDT_VERSION, soft_margin, nowayout);
869 	return 0;
870 
871 error_misc_register:
872 	hpwdt_exit_nmi_decoding();
873 error_init_nmi_decoding:
874 	pci_iounmap(dev, pci_mem_addr);
875 error_pci_iomap:
876 	pci_disable_device(dev);
877 	return retval;
878 }
879 
880 static void hpwdt_exit(struct pci_dev *dev)
881 {
882 	if (!nowayout)
883 		hpwdt_stop();
884 
885 	misc_deregister(&hpwdt_miscdev);
886 	hpwdt_exit_nmi_decoding();
887 	pci_iounmap(dev, pci_mem_addr);
888 	pci_disable_device(dev);
889 }
890 
891 static struct pci_driver hpwdt_driver = {
892 	.name = "hpwdt",
893 	.id_table = hpwdt_devices,
894 	.probe = hpwdt_init_one,
895 	.remove = hpwdt_exit,
896 };
897 
898 MODULE_AUTHOR("Tom Mingarelli");
899 MODULE_DESCRIPTION("hp watchdog driver");
900 MODULE_LICENSE("GPL");
901 MODULE_VERSION(HPWDT_VERSION);
902 
903 module_param(soft_margin, int, 0);
904 MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
905 
906 module_param(nowayout, bool, 0);
907 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
908 		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
909 
910 #ifdef CONFIG_HPWDT_NMI_DECODING
911 module_param(allow_kdump, int, 0);
912 MODULE_PARM_DESC(allow_kdump, "Start a kernel dump after NMI occurs");
913 #endif /* !CONFIG_HPWDT_NMI_DECODING */
914 
915 module_pci_driver(hpwdt_driver);
916