summaryrefslogtreecommitdiff
path: root/arch/powerpc/platforms/pseries/eeh.c
blob: 6b73d6c44f51dfb5125862e9b48852ea92af05a2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
/*
 * Copyright IBM Corporation 2001, 2005, 2006
 * Copyright Dave Engebretsen & Todd Inglett 2001
 * Copyright Linas Vepstas 2005, 2006
 * Copyright 2001-2012 IBM Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 * Please address comments and feedback to Linas Vepstas <linas@austin.ibm.com>
 */

#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/proc_fs.h>
#include <linux/rbtree.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/export.h>
#include <linux/of.h>

#include <linux/atomic.h>
#include <asm/eeh.h>
#include <asm/eeh_event.h>
#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/ppc-pci.h>
#include <asm/rtas.h>


/** Overview:
 *  EEH, or "Extended Error Handling" is a PCI bridge technology for
 *  dealing with PCI bus errors that can't be dealt with within the
 *  usual PCI framework, except by check-stopping the CPU.  Systems
 *  that are designed for high-availability/reliability cannot afford
 *  to crash due to a "mere" PCI error, thus the need for EEH.
 *  An EEH-capable bridge operates by converting a detected error
 *  into a "slot freeze", taking the PCI adapter off-line, making
 *  the slot behave, from the OS'es point of view, as if the slot
 *  were "empty": all reads return 0xff's and all writes are silently
 *  ignored.  EEH slot isolation events can be triggered by parity
 *  errors on the address or data busses (e.g. during posted writes),
 *  which in turn might be caused by low voltage on the bus, dust,
 *  vibration, humidity, radioactivity or plain-old failed hardware.
 *
 *  Note, however, that one of the leading causes of EEH slot
 *  freeze events are buggy device drivers, buggy device microcode,
 *  or buggy device hardware.  This is because any attempt by the
 *  device to bus-master data to a memory address that is not
 *  assigned to the device will trigger a slot freeze.   (The idea
 *  is to prevent devices-gone-wild from corrupting system memory).
 *  Buggy hardware/drivers will have a miserable time co-existing
 *  with EEH.
 *
 *  Ideally, a PCI device driver, when suspecting that an isolation
 *  event has occurred (e.g. by reading 0xff's), will then ask EEH
 *  whether this is the case, and then take appropriate steps to
 *  reset the PCI slot, the PCI device, and then resume operations.
 *  However, until that day,  the checking is done here, with the
 *  eeh_check_failure() routine embedded in the MMIO macros.  If
 *  the slot is found to be isolated, an "EEH Event" is synthesized
 *  and sent out for processing.
 */

/* If a device driver keeps reading an MMIO register in an interrupt
 * handler after a slot isolation event, it might be broken.
 * This sets the threshold for how many read attempts we allow
 * before printing an error message.
 */
#define EEH_MAX_FAILS	2100000

/* Time to wait for a PCI slot to report status, in milliseconds */
#define PCI_BUS_RESET_WAIT_MSEC (60*1000)

/* Platform dependent EEH operations */
struct eeh_ops *eeh_ops = NULL;

int eeh_subsystem_enabled;
EXPORT_SYMBOL(eeh_subsystem_enabled);

/*
 * EEH probe mode support. The intention is to support multiple
 * platforms for EEH. Some platforms like pSeries do PCI emunation
 * based on device tree. However, other platforms like powernv probe
 * PCI devices from hardware. The flag is used to distinguish that.
 * In addition, struct eeh_ops::probe would be invoked for particular
 * OF node or PCI device so that the corresponding PE would be created
 * there.
 */
int eeh_probe_mode;

/* Global EEH mutex */
DEFINE_MUTEX(eeh_mutex);

/* Lock to avoid races due to multiple reports of an error */
static DEFINE_RAW_SPINLOCK(confirm_error_lock);

/* Buffer for reporting pci register dumps. Its here in BSS, and
 * not dynamically alloced, so that it ends up in RMO where RTAS
 * can access it.
 */
#define EEH_PCI_REGS_LOG_LEN 4096
static unsigned char pci_regs_buf[EEH_PCI_REGS_LOG_LEN];

/*
 * The struct is used to maintain the EEH global statistic
 * information. Besides, the EEH global statistics will be
 * exported to user space through procfs
 */
struct eeh_stats {
	u64 no_device;		/* PCI device not found		*/
	u64 no_dn;		/* OF node not found		*/
	u64 no_cfg_addr;	/* Config address not found	*/
	u64 ignored_check;	/* EEH check skipped		*/
	u64 total_mmio_ffs;	/* Total EEH checks		*/
	u64 false_positives;	/* Unnecessary EEH checks	*/
	u64 slot_resets;	/* PE reset			*/
};

static struct eeh_stats eeh_stats;

#define IS_BRIDGE(class_code) (((class_code)<<16) == PCI_BASE_CLASS_BRIDGE)

/**
 * eeh_gather_pci_data - Copy assorted PCI config space registers to buff
 * @edev: device to report data for
 * @buf: point to buffer in which to log
 * @len: amount of room in buffer
 *
 * This routine captures assorted PCI configuration space data,
 * and puts them into a buffer for RTAS error logging.
 */
static size_t eeh_gather_pci_data(struct eeh_dev *edev, char * buf, size_t len)
{
	struct device_node *dn = eeh_dev_to_of_node(edev);
	struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
	u32 cfg;
	int cap, i;
	int n = 0;

	n += scnprintf(buf+n, len-n, "%s\n", dn->full_name);
	printk(KERN_WARNING "EEH: of node=%s\n", dn->full_name);

	eeh_ops->read_config(dn, PCI_VENDOR_ID, 4, &cfg);
	n += scnprintf(buf+n, len-n, "dev/vend:%08x\n", cfg);
	printk(KERN_WARNING "EEH: PCI device/vendor: %08x\n", cfg);

	eeh_ops->read_config(dn, PCI_COMMAND, 4, &cfg);
	n += scnprintf(buf+n, len-n, "cmd/stat:%x\n", cfg);
	printk(KERN_WARNING "EEH: PCI cmd/status register: %08x\n", cfg);

	if (!dev) {
		printk(KERN_WARNING "EEH: no PCI device for this of node\n");
		return n;
	}

	/* Gather bridge-specific registers */
	if (dev->class >> 16 == PCI_BASE_CLASS_BRIDGE) {
		eeh_ops->read_config(dn, PCI_SEC_STATUS, 2, &cfg);
		n += scnprintf(buf+n, len-n, "sec stat:%x\n", cfg);
		printk(KERN_WARNING "EEH: Bridge secondary status: %04x\n", cfg);

		eeh_ops->read_config(dn, PCI_BRIDGE_CONTROL, 2, &cfg);
		n += scnprintf(buf+n, len-n, "brdg ctl:%x\n", cfg);
		printk(KERN_WARNING "EEH: Bridge control: %04x\n", cfg);
	}

	/* Dump out the PCI-X command and status regs */
	cap = pci_find_capability(dev, PCI_CAP_ID_PCIX);
	if (cap) {
		eeh_ops->read_config(dn, cap, 4, &cfg);
		n += scnprintf(buf+n, len-n, "pcix-cmd:%x\n", cfg);
		printk(KERN_WARNING "EEH: PCI-X cmd: %08x\n", cfg);

		eeh_ops->read_config(dn, cap+4, 4, &cfg);
		n += scnprintf(buf+n, len-n, "pcix-stat:%x\n", cfg);
		printk(KERN_WARNING "EEH: PCI-X status: %08x\n", cfg);
	}

	/* If PCI-E capable, dump PCI-E cap 10, and the AER */
	cap = pci_find_capability(dev, PCI_CAP_ID_EXP);
	if (cap) {
		n += scnprintf(buf+n, len-n, "pci-e cap10:\n");
		printk(KERN_WARNING
		       "EEH: PCI-E capabilities and status follow:\n");

		for (i=0; i<=8; i++) {
			eeh_ops->read_config(dn, cap+4*i, 4, &cfg);
			n += scnprintf(buf+n, len-n, "%02x:%x\n", 4*i, cfg);
			printk(KERN_WARNING "EEH: PCI-E %02x: %08x\n", i, cfg);
		}

		cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
		if (cap) {
			n += scnprintf(buf+n, len-n, "pci-e AER:\n");
			printk(KERN_WARNING
			       "EEH: PCI-E AER capability register set follows:\n");

			for (i=0; i<14; i++) {
				eeh_ops->read_config(dn, cap+4*i, 4, &cfg);
				n += scnprintf(buf+n, len-n, "%02x:%x\n", 4*i, cfg);
				printk(KERN_WARNING "EEH: PCI-E AER %02x: %08x\n", i, cfg);
			}
		}
	}

	return n;
}

/**
 * eeh_slot_error_detail - Generate combined log including driver log and error log
 * @pe: EEH PE
 * @severity: temporary or permanent error log
 *
 * This routine should be called to generate the combined log, which
 * is comprised of driver log and error log. The driver log is figured
 * out from the config space of the corresponding PCI device, while
 * the error log is fetched through platform dependent function call.
 */
void eeh_slot_error_detail(struct eeh_pe *pe, int severity)
{
	size_t loglen = 0;
	struct eeh_dev *edev;

	eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
	eeh_ops->configure_bridge(pe);
	eeh_pe_restore_bars(pe);

	pci_regs_buf[0] = 0;
	eeh_pe_for_each_dev(pe, edev) {
		loglen += eeh_gather_pci_data(edev, pci_regs_buf,
				EEH_PCI_REGS_LOG_LEN);
        }

	eeh_ops->get_log(pe, severity, pci_regs_buf, loglen);
}

/**
 * eeh_token_to_phys - Convert EEH address token to phys address
 * @token: I/O token, should be address in the form 0xA....
 *
 * This routine should be called to convert virtual I/O address
 * to physical one.
 */
static inline unsigned long eeh_token_to_phys(unsigned long token)
{
	pte_t *ptep;
	unsigned long pa;

	ptep = find_linux_pte(init_mm.pgd, token);
	if (!ptep)
		return token;
	pa = pte_pfn(*ptep) << PAGE_SHIFT;

	return pa | (token & (PAGE_SIZE-1));
}

/**
 * eeh_dev_check_failure - Check if all 1's data is due to EEH slot freeze
 * @edev: eeh device
 *
 * Check for an EEH failure for the given device node.  Call this
 * routine if the result of a read was all 0xff's and you want to
 * find out if this is due to an EEH slot freeze.  This routine
 * will query firmware for the EEH status.
 *
 * Returns 0 if there has not been an EEH error; otherwise returns
 * a non-zero value and queues up a slot isolation event notification.
 *
 * It is safe to call this routine in an interrupt context.
 */
int eeh_dev_check_failure(struct eeh_dev *edev)
{
	int ret;
	unsigned long flags;
	struct device_node *dn;
	struct pci_dev *dev;
	struct eeh_pe *pe;
	int rc = 0;
	const char *location;

	eeh_stats.total_mmio_ffs++;

	if (!eeh_subsystem_enabled)
		return 0;

	if (!edev) {
		eeh_stats.no_dn++;
		return 0;
	}
	dn = eeh_dev_to_of_node(edev);
	dev = eeh_dev_to_pci_dev(edev);
	pe = edev->pe;

	/* Access to IO BARs might get this far and still not want checking. */
	if (!pe) {
		eeh_stats.ignored_check++;
		pr_debug("EEH: Ignored check for %s %s\n",
			eeh_pci_name(dev), dn->full_name);
		return 0;
	}

	if (!pe->addr && !pe->config_addr) {
		eeh_stats.no_cfg_addr++;
		return 0;
	}

	/* If we already have a pending isolation event for this
	 * slot, we know it's bad already, we don't need to check.
	 * Do this checking under a lock; as multiple PCI devices
	 * in one slot might report errors simultaneously, and we
	 * only want one error recovery routine running.
	 */
	raw_spin_lock_irqsave(&confirm_error_lock, flags);
	rc = 1;
	if (pe->state & EEH_PE_ISOLATED) {
		pe->check_count++;
		if (pe->check_count % EEH_MAX_FAILS == 0) {
			location = of_get_property(dn, "ibm,loc-code", NULL);
			printk(KERN_ERR "EEH: %d reads ignored for recovering device at "
				"location=%s driver=%s pci addr=%s\n",
				pe->check_count, location,
				eeh_driver_name(dev), eeh_pci_name(dev));
			printk(KERN_ERR "EEH: Might be infinite loop in %s driver\n",
				eeh_driver_name(dev));
			dump_stack();
		}
		goto dn_unlock;
	}

	/*
	 * Now test for an EEH failure.  This is VERY expensive.
	 * Note that the eeh_config_addr may be a parent device
	 * in the case of a device behind a bridge, or it may be
	 * function zero of a multi-function device.
	 * In any case they must share a common PHB.
	 */
	ret = eeh_ops->get_state(pe, NULL);

	/* Note that config-io to empty slots may fail;
	 * they are empty when they don't have children.
	 * We will punt with the following conditions: Failure to get
	 * PE's state, EEH not support and Permanently unavailable
	 * state, PE is in good state.
	 */
	if ((ret < 0) ||
	    (ret == EEH_STATE_NOT_SUPPORT) ||
	    (ret & (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE)) ==
	    (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE)) {
		eeh_stats.false_positives++;
		pe->false_positives++;
		rc = 0;
		goto dn_unlock;
	}

	eeh_stats.slot_resets++;
 
	/* Avoid repeated reports of this failure, including problems
	 * with other functions on this device, and functions under
	 * bridges.
	 */
	eeh_pe_state_mark(pe, EEH_PE_ISOLATED);
	raw_spin_unlock_irqrestore(&confirm_error_lock, flags);

	eeh_send_failure_event(pe);

	/* Most EEH events are due to device driver bugs.  Having
	 * a stack trace will help the device-driver authors figure
	 * out what happened.  So print that out.
	 */
	WARN(1, "EEH: failure detected\n");
	return 1;

dn_unlock:
	raw_spin_unlock_irqrestore(&confirm_error_lock, flags);
	return rc;
}

EXPORT_SYMBOL_GPL(eeh_dev_check_failure);

/**
 * eeh_check_failure - Check if all 1's data is due to EEH slot freeze
 * @token: I/O token, should be address in the form 0xA....
 * @val: value, should be all 1's (XXX why do we need this arg??)
 *
 * Check for an EEH failure at the given token address.  Call this
 * routine if the result of a read was all 0xff's and you want to
 * find out if this is due to an EEH slot freeze event.  This routine
 * will query firmware for the EEH status.
 *
 * Note this routine is safe to call in an interrupt context.
 */
unsigned long eeh_check_failure(const volatile void __iomem *token, unsigned long val)
{
	unsigned long addr;
	struct eeh_dev *edev;

	/* Finding the phys addr + pci device; this is pretty quick. */
	addr = eeh_token_to_phys((unsigned long __force) token);
	edev = eeh_addr_cache_get_dev(addr);
	if (!edev) {
		eeh_stats.no_device++;
		return val;
	}

	eeh_dev_check_failure(edev);

	pci_dev_put(eeh_dev_to_pci_dev(edev));
	return val;
}

EXPORT_SYMBOL(eeh_check_failure);


/**
 * eeh_pci_enable - Enable MMIO or DMA transfers for this slot
 * @pe: EEH PE
 *
 * This routine should be called to reenable frozen MMIO or DMA
 * so that it would work correctly again. It's useful while doing
 * recovery or log collection on the indicated device.
 */
int eeh_pci_enable(struct eeh_pe *pe, int function)
{
	int rc;

	rc = eeh_ops->set_option(pe, function);
	if (rc)
		pr_warning("%s: Unexpected state change %d on PHB#%d-PE#%x, err=%d\n",
			__func__, function, pe->phb->global_number, pe->addr, rc);

	rc = eeh_ops->wait_state(pe, PCI_BUS_RESET_WAIT_MSEC);
	if (rc > 0 && (rc & EEH_STATE_MMIO_ENABLED) &&
	   (function == EEH_OPT_THAW_MMIO))
		return 0;

	return rc;
}

/**
 * pcibios_set_pcie_slot_reset - Set PCI-E reset state
 * @dev: pci device struct
 * @state: reset state to enter
 *
 * Return value:
 * 	0 if success
 */
int pcibios_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
{
	struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);
	struct eeh_pe *pe = edev->pe;

	if (!pe) {
		pr_err("%s: No PE found on PCI device %s\n",
			__func__, pci_name(dev));
		return -EINVAL;
	}

	switch (state) {
	case pcie_deassert_reset:
		eeh_ops->reset(pe, EEH_RESET_DEACTIVATE);
		break;
	case pcie_hot_reset:
		eeh_ops->reset(pe, EEH_RESET_HOT);
		break;
	case pcie_warm_reset:
		eeh_ops->reset(pe, EEH_RESET_FUNDAMENTAL);
		break;
	default:
		return -EINVAL;
	};

	return 0;
}

/**
 * eeh_set_pe_freset - Check the required reset for the indicated device
 * @data: EEH device
 * @flag: return value
 *
 * Each device might have its preferred reset type: fundamental or
 * hot reset. The routine is used to collected the information for
 * the indicated device and its children so that the bunch of the
 * devices could be reset properly.
 */
static void *eeh_set_dev_freset(void *data, void *flag)
{
	struct pci_dev *dev;
	unsigned int *freset = (unsigned int *)flag;
	struct eeh_dev *edev = (struct eeh_dev *)data;

	dev = eeh_dev_to_pci_dev(edev);
	if (dev)
		*freset |= dev->needs_freset;

	return NULL;
}

/**
 * eeh_reset_pe_once - Assert the pci #RST line for 1/4 second
 * @pe: EEH PE
 *
 * Assert the PCI #RST line for 1/4 second.
 */
static void eeh_reset_pe_once(struct eeh_pe *pe)
{
	unsigned int freset = 0;

	/* Determine type of EEH reset required for
	 * Partitionable Endpoint, a hot-reset (1)
	 * or a fundamental reset (3).
	 * A fundamental reset required by any device under
	 * Partitionable Endpoint trumps hot-reset.
  	 */
	eeh_pe_dev_traverse(pe, eeh_set_dev_freset, &freset);

	if (freset)
		eeh_ops->reset(pe, EEH_RESET_FUNDAMENTAL);
	else
		eeh_ops->reset(pe, EEH_RESET_HOT);

	/* The PCI bus requires that the reset be held high for at least
	 * a 100 milliseconds. We wait a bit longer 'just in case'.
	 */
#define PCI_BUS_RST_HOLD_TIME_MSEC 250
	msleep(PCI_BUS_RST_HOLD_TIME_MSEC);
	
	/* We might get hit with another EEH freeze as soon as the 
	 * pci slot reset line is dropped. Make sure we don't miss
	 * these, and clear the flag now.
	 */
	eeh_pe_state_clear(pe, EEH_PE_ISOLATED);

	eeh_ops->reset(pe, EEH_RESET_DEACTIVATE);

	/* After a PCI slot has been reset, the PCI Express spec requires
	 * a 1.5 second idle time for the bus to stabilize, before starting
	 * up traffic.
	 */
#define PCI_BUS_SETTLE_TIME_MSEC 1800
	msleep(PCI_BUS_SETTLE_TIME_MSEC);
}

/**
 * eeh_reset_pe - Reset the indicated PE
 * @pe: EEH PE
 *
 * This routine should be called to reset indicated device, including
 * PE. A PE might include multiple PCI devices and sometimes PCI bridges
 * might be involved as well.
 */
int eeh_reset_pe(struct eeh_pe *pe)
{
	int i, rc;

	/* Take three shots at resetting the bus */
	for (i=0; i<3; i++) {
		eeh_reset_pe_once(pe);

		rc = eeh_ops->wait_state(pe, PCI_BUS_RESET_WAIT_MSEC);
		if (rc == (EEH_STATE_MMIO_ACTIVE | EEH_STATE_DMA_ACTIVE))
			return 0;

		if (rc < 0) {
			pr_err("%s: Unrecoverable slot failure on PHB#%d-PE#%x",
				__func__, pe->phb->global_number, pe->addr);
			return -1;
		}
		pr_err("EEH: bus reset %d failed on PHB#%d-PE#%x, rc=%d\n",
			i+1, pe->phb->global_number, pe->addr, rc);
	}

	return -1;
}

/**
 * eeh_save_bars - Save device bars
 * @edev: PCI device associated EEH device
 *
 * Save the values of the device bars. Unlike the restore
 * routine, this routine is *not* recursive. This is because
 * PCI devices are added individually; but, for the restore,
 * an entire slot is reset at a time.
 */
void eeh_save_bars(struct eeh_dev *edev)
{
	int i;
	struct device_node *dn;

	if (!edev)
		return;
	dn = eeh_dev_to_of_node(edev);
	
	for (i = 0; i < 16; i++)
		eeh_ops->read_config(dn, i * 4, 4, &edev->config_space[i]);
}

/**
 * eeh_ops_register - Register platform dependent EEH operations
 * @ops: platform dependent EEH operations
 *
 * Register the platform dependent EEH operation callback
 * functions. The platform should call this function before
 * any other EEH operations.
 */
int __init eeh_ops_register(struct eeh_ops *ops)
{
	if (!ops->name) {
		pr_warning("%s: Invalid EEH ops name for %p\n",
			__func__, ops);
		return -EINVAL;
	}

	if (eeh_ops && eeh_ops != ops) {
		pr_warning("%s: EEH ops of platform %s already existing (%s)\n",
			__func__, eeh_ops->name, ops->name);
		return -EEXIST;
	}

	eeh_ops = ops;

	return 0;
}

/**
 * eeh_ops_unregister - Unreigster platform dependent EEH operations
 * @name: name of EEH platform operations
 *
 * Unregister the platform dependent EEH operation callback
 * functions.
 */
int __exit eeh_ops_unregister(const char *name)
{
	if (!name || !strlen(name)) {
		pr_warning("%s: Invalid EEH ops name\n",
			__func__);
		return -EINVAL;
	}

	if (eeh_ops && !strcmp(eeh_ops->name, name)) {
		eeh_ops = NULL;
		return 0;
	}

	return -EEXIST;
}

/**
 * eeh_init - EEH initialization
 *
 * Initialize EEH by trying to enable it for all of the adapters in the system.
 * As a side effect we can determine here if eeh is supported at all.
 * Note that we leave EEH on so failed config cycles won't cause a machine
 * check.  If a user turns off EEH for a particular adapter they are really
 * telling Linux to ignore errors.  Some hardware (e.g. POWER5) won't
 * grant access to a slot if EEH isn't enabled, and so we always enable
 * EEH for all slots/all devices.
 *
 * The eeh-force-off option disables EEH checking globally, for all slots.
 * Even if force-off is set, the EEH hardware is still enabled, so that
 * newer systems can boot.
 */
static int __init eeh_init(void)
{
	struct pci_controller *hose, *tmp;
	struct device_node *phb;
	int ret;

	/* call platform initialization function */
	if (!eeh_ops) {
		pr_warning("%s: Platform EEH operation not found\n",
			__func__);
		return -EEXIST;
	} else if ((ret = eeh_ops->init())) {
		pr_warning("%s: Failed to call platform init function (%d)\n",
			__func__, ret);
		return ret;
	}

	raw_spin_lock_init(&confirm_error_lock);

	/* Enable EEH for all adapters */
	if (eeh_probe_mode_devtree()) {
		list_for_each_entry_safe(hose, tmp,
			&hose_list, list_node) {
			phb = hose->dn;
			traverse_pci_devices(phb, eeh_ops->of_probe, NULL);
		}
	}

	if (eeh_subsystem_enabled)
		pr_info("EEH: PCI Enhanced I/O Error Handling Enabled\n");
	else
		pr_warning("EEH: No capable adapters found\n");

	return ret;
}

core_initcall_sync(eeh_init);

/**
 * eeh_add_device_early - Enable EEH for the indicated device_node
 * @dn: device node for which to set up EEH
 *
 * This routine must be used to perform EEH initialization for PCI
 * devices that were added after system boot (e.g. hotplug, dlpar).
 * This routine must be called before any i/o is performed to the
 * adapter (inluding any config-space i/o).
 * Whether this actually enables EEH or not for this device depends
 * on the CEC architecture, type of the device, on earlier boot
 * command-line arguments & etc.
 */
static void eeh_add_device_early(struct device_node *dn)
{
	struct pci_controller *phb;

	if (!of_node_to_eeh_dev(dn))
		return;
	phb = of_node_to_eeh_dev(dn)->phb;

	/* USB Bus children of PCI devices will not have BUID's */
	if (NULL == phb || 0 == phb->buid)
		return;

	/* FIXME: hotplug support on POWERNV */
	eeh_ops->of_probe(dn, NULL);
}

/**
 * eeh_add_device_tree_early - Enable EEH for the indicated device
 * @dn: device node
 *
 * This routine must be used to perform EEH initialization for the
 * indicated PCI device that was added after system boot (e.g.
 * hotplug, dlpar).
 */
void eeh_add_device_tree_early(struct device_node *dn)
{
	struct device_node *sib;

	for_each_child_of_node(dn, sib)
		eeh_add_device_tree_early(sib);
	eeh_add_device_early(dn);
}
EXPORT_SYMBOL_GPL(eeh_add_device_tree_early);

/**
 * eeh_add_device_late - Perform EEH initialization for the indicated pci device
 * @dev: pci device for which to set up EEH
 *
 * This routine must be used to complete EEH initialization for PCI
 * devices that were added after system boot (e.g. hotplug, dlpar).
 */
static void eeh_add_device_late(struct pci_dev *dev)
{
	struct device_node *dn;
	struct eeh_dev *edev;

	if (!dev || !eeh_subsystem_enabled)
		return;

	pr_debug("EEH: Adding device %s\n", pci_name(dev));

	dn = pci_device_to_OF_node(dev);
	edev = of_node_to_eeh_dev(dn);
	if (edev->pdev == dev) {
		pr_debug("EEH: Already referenced !\n");
		return;
	}
	WARN_ON(edev->pdev);

	pci_dev_get(dev);
	edev->pdev = dev;
	dev->dev.archdata.edev = edev;

	eeh_addr_cache_insert_dev(dev);
}

/**
 * eeh_add_device_tree_late - Perform EEH initialization for the indicated PCI bus
 * @bus: PCI bus
 *
 * This routine must be used to perform EEH initialization for PCI
 * devices which are attached to the indicated PCI bus. The PCI bus
 * is added after system boot through hotplug or dlpar.
 */
void eeh_add_device_tree_late(struct pci_bus *bus)
{
	struct pci_dev *dev;

	list_for_each_entry(dev, &bus->devices, bus_list) {
 		eeh_add_device_late(dev);
 		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
 			struct pci_bus *subbus = dev->subordinate;
 			if (subbus)
 				eeh_add_device_tree_late(subbus);
 		}
	}
}
EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);

/**
 * eeh_add_sysfs_files - Add EEH sysfs files for the indicated PCI bus
 * @bus: PCI bus
 *
 * This routine must be used to add EEH sysfs files for PCI
 * devices which are attached to the indicated PCI bus. The PCI bus
 * is added after system boot through hotplug or dlpar.
 */
void eeh_add_sysfs_files(struct pci_bus *bus)
{
	struct pci_dev *dev;

	list_for_each_entry(dev, &bus->devices, bus_list) {
		eeh_sysfs_add_device(dev);
		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
			struct pci_bus *subbus = dev->subordinate;
			if (subbus)
				eeh_add_sysfs_files(subbus);
		}
	}
}
EXPORT_SYMBOL_GPL(eeh_add_sysfs_files);

/**
 * eeh_remove_device - Undo EEH setup for the indicated pci device
 * @dev: pci device to be removed
 * @purge_pe: remove the PE or not
 *
 * This routine should be called when a device is removed from
 * a running system (e.g. by hotplug or dlpar).  It unregisters
 * the PCI device from the EEH subsystem.  I/O errors affecting
 * this device will no longer be detected after this call; thus,
 * i/o errors affecting this slot may leave this device unusable.
 */
static void eeh_remove_device(struct pci_dev *dev, int purge_pe)
{
	struct eeh_dev *edev;

	if (!dev || !eeh_subsystem_enabled)
		return;
	edev = pci_dev_to_eeh_dev(dev);

	/* Unregister the device with the EEH/PCI address search system */
	pr_debug("EEH: Removing device %s\n", pci_name(dev));

	if (!edev || !edev->pdev) {
		pr_debug("EEH: Not referenced !\n");
		return;
	}
	edev->pdev = NULL;
	dev->dev.archdata.edev = NULL;
	pci_dev_put(dev);

	eeh_rmv_from_parent_pe(edev, purge_pe);
	eeh_addr_cache_rmv_dev(dev);
	eeh_sysfs_remove_device(dev);
}

/**
 * eeh_remove_bus_device - Undo EEH setup for the indicated PCI device
 * @dev: PCI device
 * @purge_pe: remove the corresponding PE or not
 *
 * This routine must be called when a device is removed from the
 * running system through hotplug or dlpar. The corresponding
 * PCI address cache will be removed.
 */
void eeh_remove_bus_device(struct pci_dev *dev, int purge_pe)
{
	struct pci_bus *bus = dev->subordinate;
	struct pci_dev *child, *tmp;

	eeh_remove_device(dev, purge_pe);

	if (bus && dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
		list_for_each_entry_safe(child, tmp, &bus->devices, bus_list)
			 eeh_remove_bus_device(child, purge_pe);
	}
}
EXPORT_SYMBOL_GPL(eeh_remove_bus_device);

static int proc_eeh_show(struct seq_file *m, void *v)
{
	if (0 == eeh_subsystem_enabled) {
		seq_printf(m, "EEH Subsystem is globally disabled\n");
		seq_printf(m, "eeh_total_mmio_ffs=%llu\n", eeh_stats.total_mmio_ffs);
	} else {
		seq_printf(m, "EEH Subsystem is enabled\n");
		seq_printf(m,
				"no device=%llu\n"
				"no device node=%llu\n"
				"no config address=%llu\n"
				"check not wanted=%llu\n"
				"eeh_total_mmio_ffs=%llu\n"
				"eeh_false_positives=%llu\n"
				"eeh_slot_resets=%llu\n",
				eeh_stats.no_device,
				eeh_stats.no_dn,
				eeh_stats.no_cfg_addr,
				eeh_stats.ignored_check,
				eeh_stats.total_mmio_ffs,
				eeh_stats.false_positives,
				eeh_stats.slot_resets);
	}

	return 0;
}

static int proc_eeh_open(struct inode *inode, struct file *file)
{
	return single_open(file, proc_eeh_show, NULL);
}

static const struct file_operations proc_eeh_operations = {
	.open      = proc_eeh_open,
	.read      = seq_read,
	.llseek    = seq_lseek,
	.release   = single_release,
};

static int __init eeh_init_proc(void)
{
	if (machine_is(pseries))
		proc_create("powerpc/eeh", 0, NULL, &proc_eeh_operations);
	return 0;
}
__initcall(eeh_init_proc);