aboutsummaryrefslogtreecommitdiff
path: root/drivers/infiniband/hw/ehca/ehca_irq.c
blob: 53589000fd0726d95a8d817505f131e165909f56 (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
/*
 *  IBM eServer eHCA Infiniband device driver for Linux on POWER
 *
 *  Functions for EQs, NEQs and interrupts
 *
 *  Authors: Heiko J Schick <schickhj@de.ibm.com>
 *           Khadija Souissi <souissi@de.ibm.com>
 *           Hoang-Nam Nguyen <hnguyen@de.ibm.com>
 *           Joachim Fenkes <fenkes@de.ibm.com>
 *
 *  Copyright (c) 2005 IBM Corporation
 *
 *  All rights reserved.
 *
 *  This source code is distributed under a dual license of GPL v2.0 and OpenIB
 *  BSD.
 *
 * OpenIB BSD License
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials
 * provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/slab.h>

#include "ehca_classes.h"
#include "ehca_irq.h"
#include "ehca_iverbs.h"
#include "ehca_tools.h"
#include "hcp_if.h"
#include "hipz_fns.h"
#include "ipz_pt_fn.h"

#define EQE_COMPLETION_EVENT   EHCA_BMASK_IBM( 1,  1)
#define EQE_CQ_QP_NUMBER       EHCA_BMASK_IBM( 8, 31)
#define EQE_EE_IDENTIFIER      EHCA_BMASK_IBM( 2,  7)
#define EQE_CQ_NUMBER          EHCA_BMASK_IBM( 8, 31)
#define EQE_QP_NUMBER          EHCA_BMASK_IBM( 8, 31)
#define EQE_QP_TOKEN           EHCA_BMASK_IBM(32, 63)
#define EQE_CQ_TOKEN           EHCA_BMASK_IBM(32, 63)

#define NEQE_COMPLETION_EVENT  EHCA_BMASK_IBM( 1,  1)
#define NEQE_EVENT_CODE        EHCA_BMASK_IBM( 2,  7)
#define NEQE_PORT_NUMBER       EHCA_BMASK_IBM( 8, 15)
#define NEQE_PORT_AVAILABILITY EHCA_BMASK_IBM(16, 16)
#define NEQE_DISRUPTIVE        EHCA_BMASK_IBM(16, 16)
#define NEQE_SPECIFIC_EVENT    EHCA_BMASK_IBM(16, 23)

#define ERROR_DATA_LENGTH      EHCA_BMASK_IBM(52, 63)
#define ERROR_DATA_TYPE        EHCA_BMASK_IBM( 0,  7)

static void queue_comp_task(struct ehca_cq *__cq);

static struct ehca_comp_pool *pool;

static inline void comp_event_callback(struct ehca_cq *cq)
{
	if (!cq->ib_cq.comp_handler)
		return;

	spin_lock(&cq->cb_lock);
	cq->ib_cq.comp_handler(&cq->ib_cq, cq->ib_cq.cq_context);
	spin_unlock(&cq->cb_lock);

	return;
}

static void print_error_data(struct ehca_shca *shca, void *data,
			     u64 *rblock, int length)
{
	u64 type = EHCA_BMASK_GET(ERROR_DATA_TYPE, rblock[2]);
	u64 resource = rblock[1];

	switch (type) {
	case 0x1: /* Queue Pair */
	{
		struct ehca_qp *qp = (struct ehca_qp *)data;

		/* only print error data if AER is set */
		if (rblock[6] == 0)
			return;

		ehca_err(&shca->ib_device,
			 "QP 0x%x (resource=%llx) has errors.",
			 qp->ib_qp.qp_num, resource);
		break;
	}
	case 0x4: /* Completion Queue */
	{
		struct ehca_cq *cq = (struct ehca_cq *)data;

		ehca_err(&shca->ib_device,
			 "CQ 0x%x (resource=%llx) has errors.",
			 cq->cq_number, resource);
		break;
	}
	default:
		ehca_err(&shca->ib_device,
			 "Unknown error type: %llx on %s.",
			 type, shca->ib_device.name);
		break;
	}

	ehca_err(&shca->ib_device, "Error data is available: %llx.", resource);
	ehca_err(&shca->ib_device, "EHCA ----- error data begin "
		 "---------------------------------------------------");
	ehca_dmp(rblock, length, "resource=%llx", resource);
	ehca_err(&shca->ib_device, "EHCA ----- error data end "
		 "----------------------------------------------------");

	return;
}

int ehca_error_data(struct ehca_shca *shca, void *data,
		    u64 resource)
{

	unsigned long ret;
	u64 *rblock;
	unsigned long block_count;

	rblock = ehca_alloc_fw_ctrlblock(GFP_ATOMIC);
	if (!rblock) {
		ehca_err(&shca->ib_device, "Cannot allocate rblock memory.");
		ret = -ENOMEM;
		goto error_data1;
	}

	/* rblock must be 4K aligned and should be 4K large */
	ret = hipz_h_error_data(shca->ipz_hca_handle,
				resource,
				rblock,
				&block_count);

	if (ret == H_R_STATE)
		ehca_err(&shca->ib_device,
			 "No error data is available: %llx.", resource);
	else if (ret == H_SUCCESS) {
		int length;

		length = EHCA_BMASK_GET(ERROR_DATA_LENGTH, rblock[0]);

		if (length > EHCA_PAGESIZE)
			length = EHCA_PAGESIZE;

		print_error_data(shca, data, rblock, length);
	} else
		ehca_err(&shca->ib_device,
			 "Error data could not be fetched: %llx", resource);

	ehca_free_fw_ctrlblock(rblock);

error_data1:
	return ret;

}

static void dispatch_qp_event(struct ehca_shca *shca, struct ehca_qp *qp,
			      enum ib_event_type event_type)
{
	struct ib_event event;

	/* PATH_MIG without the QP ever having been armed is false alarm */
	if (event_type == IB_EVENT_PATH_MIG && !qp->mig_armed)
		return;

	event.device = &shca->ib_device;
	event.event = event_type;

	if (qp->ext_type == EQPT_SRQ) {
		if (!qp->ib_srq.event_handler)
			return;

		event.element.srq = &qp->ib_srq;
		qp->ib_srq.event_handler(&event, qp->ib_srq.srq_context);
	} else {
		if (!qp->ib_qp.event_handler)
			return;

		event.element.qp = &qp->ib_qp;
		qp->ib_qp.event_handler(&event, qp->ib_qp.qp_context);
	}
}

static void qp_event_callback(struct ehca_shca *shca, u64 eqe,
			      enum ib_event_type event_type, int fatal)
{
	struct ehca_qp *qp;
	u32 token = EHCA_BMASK_GET(EQE_QP_TOKEN, eqe);

	read_lock(&ehca_qp_idr_lock);
	qp = idr_find(&ehca_qp_idr, token);
	if (qp)
		atomic_inc(&qp->nr_events);
	read_unlock(&ehca_qp_idr_lock);

	if (!qp)
		return;

	if (fatal)
		ehca_error_data(shca, qp, qp->ipz_qp_handle.handle);

	dispatch_qp_event(shca, qp, fatal && qp->ext_type == EQPT_SRQ ?
			  IB_EVENT_SRQ_ERR : event_type);

	/*
	 * eHCA only processes one WQE at a time for SRQ base QPs,
	 * so the last WQE has been processed as soon as the QP enters
	 * error state.
	 */
	if (fatal && qp->ext_type == EQPT_SRQBASE)
		dispatch_qp_event(shca, qp, IB_EVENT_QP_LAST_WQE_REACHED);

	if (atomic_dec_and_test(&qp->nr_events))
		wake_up(&qp->wait_completion);
	return;
}

static void cq_event_callback(struct ehca_shca *shca,
			      u64 eqe)
{
	struct ehca_cq *cq;
	u32 token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe);

	read_lock(&ehca_cq_idr_lock);
	cq = idr_find(&ehca_cq_idr, token);
	if (cq)
		atomic_inc(&cq->nr_events);
	read_unlock(&ehca_cq_idr_lock);

	if (!cq)
		return;

	ehca_error_data(shca, cq, cq->ipz_cq_handle.handle);

	if (atomic_dec_and_test(&cq->nr_events))
		wake_up(&cq->wait_completion);

	return;
}

static void parse_identifier(struct ehca_shca *shca, u64 eqe)
{
	u8 identifier = EHCA_BMASK_GET(EQE_EE_IDENTIFIER, eqe);

	switch (identifier) {
	case 0x02: /* path migrated */
		qp_event_callback(shca, eqe, IB_EVENT_PATH_MIG, 0);
		break;
	case 0x03: /* communication established */
		qp_event_callback(shca, eqe, IB_EVENT_COMM_EST, 0);
		break;
	case 0x04: /* send queue drained */
		qp_event_callback(shca, eqe, IB_EVENT_SQ_DRAINED, 0);
		break;
	case 0x05: /* QP error */
	case 0x06: /* QP error */
		qp_event_callback(shca, eqe, IB_EVENT_QP_FATAL, 1);
		break;
	case 0x07: /* CQ error */
	case 0x08: /* CQ error */
		cq_event_callback(shca, eqe);
		break;
	case 0x09: /* MRMWPTE error */
		ehca_err(&shca->ib_device, "MRMWPTE error.");
		break;
	case 0x0A: /* port event */
		ehca_err(&shca->ib_device, "Port event.");
		break;
	case 0x0B: /* MR access error */
		ehca_err(&shca->ib_device, "MR access error.");
		break;
	case 0x0C: /* EQ error */
		ehca_err(&shca->ib_device, "EQ error.");
		break;
	case 0x0D: /* P/Q_Key mismatch */
		ehca_err(&shca->ib_device, "P/Q_Key mismatch.");
		break;
	case 0x10: /* sampling complete */
		ehca_err(&shca->ib_device, "Sampling complete.");
		break;
	case 0x11: /* unaffiliated access error */
		ehca_err(&shca->ib_device, "Unaffiliated access error.");
		break;
	case 0x12: /* path migrating */
		ehca_err(&shca->ib_device, "Path migrating.");
		break;
	case 0x13: /* interface trace stopped */
		ehca_err(&shca->ib_device, "Interface trace stopped.");
		break;
	case 0x14: /* first error capture info available */
		ehca_info(&shca->ib_device, "First error capture available");
		break;
	case 0x15: /* SRQ limit reached */
		qp_event_callback(shca, eqe, IB_EVENT_SRQ_LIMIT_REACHED, 0);
		break;
	default:
		ehca_err(&shca->ib_device, "Unknown identifier: %x on %s.",
			 identifier, shca->ib_device.name);
		break;
	}

	return;
}

static void dispatch_port_event(struct ehca_shca *shca, int port_num,
				enum ib_event_type type, const char *msg)
{
	struct ib_event event;

	ehca_info(&shca->ib_device, "port %d %s.", port_num, msg);
	event.device = &shca->ib_device;
	event.event = type;
	event.element.port_num = port_num;
	ib_dispatch_event(&event);
}

static void notify_port_conf_change(struct ehca_shca *shca, int port_num)
{
	struct ehca_sma_attr  new_attr;
	struct ehca_sma_attr *old_attr = &shca->sport[port_num - 1].saved_attr;

	ehca_query_sma_attr(shca, port_num, &new_attr);

	if (new_attr.sm_sl  != old_attr->sm_sl ||
	    new_attr.sm_lid != old_attr->sm_lid)
		dispatch_port_event(shca, port_num, IB_EVENT_SM_CHANGE,
				    "SM changed");

	if (new_attr.lid != old_attr->lid ||
	    new_attr.lmc != old_attr->lmc)
		dispatch_port_event(shca, port_num, IB_EVENT_LID_CHANGE,
				    "LID changed");

	if (new_attr.pkey_tbl_len != old_attr->pkey_tbl_len ||
	    memcmp(new_attr.pkeys, old_attr->pkeys,
		   sizeof(u16) * new_attr.pkey_tbl_len))
		dispatch_port_event(shca, port_num, IB_EVENT_PKEY_CHANGE,
				    "P_Key changed");

	*old_attr = new_attr;
}

/* replay modify_qp for sqps -- return 0 if all is well, 1 if AQP1 destroyed */
static int replay_modify_qp(struct ehca_sport *sport)
{
	int aqp1_destroyed;
	unsigned long flags;

	spin_lock_irqsave(&sport->mod_sqp_lock, flags);

	aqp1_destroyed = !sport->ibqp_sqp[IB_QPT_GSI];

	if (sport->ibqp_sqp[IB_QPT_SMI])
		ehca_recover_sqp(sport->ibqp_sqp[IB_QPT_SMI]);
	if (!aqp1_destroyed)
		ehca_recover_sqp(sport->ibqp_sqp[IB_QPT_GSI]);

	spin_unlock_irqrestore(&sport->mod_sqp_lock, flags);

	return aqp1_destroyed;
}

static void parse_ec(struct ehca_shca *shca, u64 eqe)
{
	u8 ec   = EHCA_BMASK_GET(NEQE_EVENT_CODE, eqe);
	u8 port = EHCA_BMASK_GET(NEQE_PORT_NUMBER, eqe);
	u8 spec_event;
	struct ehca_sport *sport = &shca->sport[port - 1];

	switch (ec) {
	case 0x30: /* port availability change */
		if (EHCA_BMASK_GET(NEQE_PORT_AVAILABILITY, eqe)) {
			/* only replay modify_qp calls in autodetect mode;
			 * if AQP1 was destroyed, the port is already down
			 * again and we can drop the event.
			 */
			if (ehca_nr_ports < 0)
				if (replay_modify_qp(sport))
					break;

			sport->port_state = IB_PORT_ACTIVE;
			dispatch_port_event(shca, port, IB_EVENT_PORT_ACTIVE,
					    "is active");
			ehca_query_sma_attr(shca, port, &sport->saved_attr);
		} else {
			sport->port_state = IB_PORT_DOWN;
			dispatch_port_event(shca, port, IB_EVENT_PORT_ERR,
					    "is inactive");
		}
		break;
	case 0x31:
		/* port configuration change
		 * disruptive change is caused by
		 * LID, PKEY or SM change
		 */
		if (EHCA_BMASK_GET(NEQE_DISRUPTIVE, eqe)) {
			ehca_warn(&shca->ib_device, "disruptive port "
				  "%d configuration change", port);

			sport->port_state = IB_PORT_DOWN;
			dispatch_port_event(shca, port, IB_EVENT_PORT_ERR,
					    "is inactive");

			sport->port_state = IB_PORT_ACTIVE;
			dispatch_port_event(shca, port, IB_EVENT_PORT_ACTIVE,
					    "is active");
			ehca_query_sma_attr(shca, port,
					    &sport->saved_attr);
		} else
			notify_port_conf_change(shca, port);
		break;
	case 0x32: /* adapter malfunction */
		ehca_err(&shca->ib_device, "Adapter malfunction.");
		break;
	case 0x33:  /* trace stopped */
		ehca_err(&shca->ib_device, "Traced stopped.");
		break;
	case 0x34: /* util async event */
		spec_event = EHCA_BMASK_GET(NEQE_SPECIFIC_EVENT, eqe);
		if (spec_event == 0x80) /* client reregister required */
			dispatch_port_event(shca, port,
					    IB_EVENT_CLIENT_REREGISTER,
					    "client reregister req.");
		else
			ehca_warn(&shca->ib_device, "Unknown util async "
				  "event %x on port %x", spec_event, port);
		break;
	default:
		ehca_err(&shca->ib_device, "Unknown event code: %x on %s.",
			 ec, shca->ib_device.name);
		break;
	}

	return;
}

static inline void reset_eq_pending(struct ehca_cq *cq)
{
	u64 CQx_EP;
	struct h_galpa gal = cq->galpas.kernel;

	hipz_galpa_store_cq(gal, cqx_ep, 0x0);
	CQx_EP = hipz_galpa_load(gal, CQTEMM_OFFSET(cqx_ep));

	return;
}

irqreturn_t ehca_interrupt_neq(int irq, void *dev_id)
{
	struct ehca_shca *shca = (struct ehca_shca*)dev_id;

	tasklet_hi_schedule(&shca->neq.interrupt_task);

	return IRQ_HANDLED;
}

void ehca_tasklet_neq(unsigned long data)
{
	struct ehca_shca *shca = (struct ehca_shca*)data;
	struct ehca_eqe *eqe;
	u64 ret;

	eqe = ehca_poll_eq(shca, &shca->neq);

	while (eqe) {
		if (!EHCA_BMASK_GET(NEQE_COMPLETION_EVENT, eqe->entry))
			parse_ec(shca, eqe->entry);

		eqe = ehca_poll_eq(shca, &shca->neq);
	}

	ret = hipz_h_reset_event(shca->ipz_hca_handle,
				 shca->neq.ipz_eq_handle, 0xFFFFFFFFFFFFFFFFL);

	if (ret != H_SUCCESS)
		ehca_err(&shca->ib_device, "Can't clear notification events.");

	return;
}

irqreturn_t ehca_interrupt_eq(int irq, void *dev_id)
{
	struct ehca_shca *shca = (struct ehca_shca*)dev_id;

	tasklet_hi_schedule(&shca->eq.interrupt_task);

	return IRQ_HANDLED;
}


static inline void process_eqe(struct ehca_shca *shca, struct ehca_eqe *eqe)
{
	u64 eqe_value;
	u32 token;
	struct ehca_cq *cq;

	eqe_value = eqe->entry;
	ehca_dbg(&shca->ib_device, "eqe_value=%llx", eqe_value);
	if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT, eqe_value)) {
		ehca_dbg(&shca->ib_device, "Got completion event");
		token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe_value);
		read_lock(&ehca_cq_idr_lock);
		cq = idr_find(&ehca_cq_idr, token);
		if (cq)
			atomic_inc(&cq->nr_events);
		read_unlock(&ehca_cq_idr_lock);
		if (cq == NULL) {
			ehca_err(&shca->ib_device,
				 "Invalid eqe for non-existing cq token=%x",
				 token);
			return;
		}
		reset_eq_pending(cq);
		if (ehca_scaling_code)
			queue_comp_task(cq);
		else {
			comp_event_callback(cq);
			if (atomic_dec_and_test(&cq->nr_events))
				wake_up(&cq->wait_completion);
		}
	} else {
		ehca_dbg(&shca->ib_device, "Got non completion event");
		parse_identifier(shca, eqe_value);
	}
}

void ehca_process_eq(struct ehca_shca *shca, int is_irq)
{
	struct ehca_eq *eq = &shca->eq;
	struct ehca_eqe_cache_entry *eqe_cache = eq->eqe_cache;
	u64 eqe_value, ret;
	int eqe_cnt, i;
	int eq_empty = 0;

	spin_lock(&eq->irq_spinlock);
	if (is_irq) {
		const int max_query_cnt = 100;
		int query_cnt = 0;
		int int_state = 1;
		do {
			int_state = hipz_h_query_int_state(
				shca->ipz_hca_handle, eq->ist);
			query_cnt++;
			iosync();
		} while (int_state && query_cnt < max_query_cnt);
		if (unlikely((query_cnt == max_query_cnt)))
			ehca_dbg(&shca->ib_device, "int_state=%x query_cnt=%x",
				 int_state, query_cnt);
	}

	/* read out all eqes */
	eqe_cnt = 0;
	do {
		u32 token;
		eqe_cache[eqe_cnt].eqe = ehca_poll_eq(shca, eq);
		if (!eqe_cache[eqe_cnt].eqe)
			break;
		eqe_value = eqe_cache[eqe_cnt].eqe->entry;
		if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT, eqe_value)) {
			token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe_value);
			read_lock(&ehca_cq_idr_lock);
			eqe_cache[eqe_cnt].cq = idr_find(&ehca_cq_idr, token);
			if (eqe_cache[eqe_cnt].cq)
				atomic_inc(&eqe_cache[eqe_cnt].cq->nr_events);
			read_unlock(&ehca_cq_idr_lock);
			if (!eqe_cache[eqe_cnt].cq) {
				ehca_err(&shca->ib_device,
					 "Invalid eqe for non-existing cq "
					 "token=%x", token);
				continue;
			}
		} else
			eqe_cache[eqe_cnt].cq = NULL;
		eqe_cnt++;
	} while (eqe_cnt < EHCA_EQE_CACHE_SIZE);
	if (!eqe_cnt) {
		if (is_irq)
			ehca_dbg(&shca->ib_device,
				 "No eqe found for irq event");
		goto unlock_irq_spinlock;
	} else if (!is_irq) {
		ret = hipz_h_eoi(eq->ist);
		if (ret != H_SUCCESS)
			ehca_err(&shca->ib_device,
				 "bad return code EOI -rc = %lld\n", ret);
		ehca_dbg(&shca->ib_device, "deadman found %x eqe", eqe_cnt);
	}
	if (unlikely(eqe_cnt == EHCA_EQE_CACHE_SIZE))
		ehca_dbg(&shca->ib_device, "too many eqes for one irq event");
	/* enable irq for new packets */
	for (i = 0; i < eqe_cnt; i++) {
		if (eq->eqe_cache[i].cq)
			reset_eq_pending(eq->eqe_cache[i].cq);
	}
	/* check eq */
	spin_lock(&eq->spinlock);
	eq_empty = (!ipz_eqit_eq_peek_valid(&shca->eq.ipz_queue));
	spin_unlock(&eq->spinlock);
	/* call completion handler for cached eqes */
	for (i = 0; i < eqe_cnt; i++)
		if (eq->eqe_cache[i].cq) {
			if (ehca_scaling_code)
				queue_comp_task(eq->eqe_cache[i].cq);
			else {
				struct ehca_cq *cq = eq->eqe_cache[i].cq;
				comp_event_callback(cq);
				if (atomic_dec_and_test(&cq->nr_events))
					wake_up(&cq->wait_completion);
			}
		} else {
			ehca_dbg(&shca->ib_device, "Got non completion event");
			parse_identifier(shca, eq->eqe_cache[i].eqe->entry);
		}
	/* poll eq if not empty */
	if (eq_empty)
		goto unlock_irq_spinlock;
	do {
		struct ehca_eqe *eqe;
		eqe = ehca_poll_eq(shca, &shca->eq);
		if (!eqe)
			break;
		process_eqe(shca, eqe);
	} while (1);

unlock_irq_spinlock:
	spin_unlock(&eq->irq_spinlock);
}

void ehca_tasklet_eq(unsigned long data)
{
	ehca_process_eq((struct ehca_shca*)data, 1);
}

static inline int find_next_online_cpu(struct ehca_comp_pool *pool)
{
	int cpu;
	unsigned long flags;

	WARN_ON_ONCE(!in_interrupt());
	if (ehca_debug_level >= 3)
		ehca_dmp(cpu_online_mask, cpumask_size(), "");

	spin_lock_irqsave(&pool->last_cpu_lock, flags);
	cpu = cpumask_next(pool->last_cpu, cpu_online_mask);
	if (cpu >= nr_cpu_ids)
		cpu = cpumask_first(cpu_online_mask);
	pool->last_cpu = cpu;
	spin_unlock_irqrestore(&pool->last_cpu_lock, flags);

	return cpu;
}

static void __queue_comp_task(struct ehca_cq *__cq,
			      struct ehca_cpu_comp_task *cct)
{
	unsigned long flags;

	spin_lock_irqsave(&cct->task_lock, flags);
	spin_lock(&__cq->task_lock);

	if (__cq->nr_callbacks == 0) {
		__cq->nr_callbacks++;
		list_add_tail(&__cq->entry, &cct->cq_list);
		cct->cq_jobs++;
		wake_up(&cct->wait_queue);
	} else
		__cq->nr_callbacks++;

	spin_unlock(&__cq->task_lock);
	spin_unlock_irqrestore(&cct->task_lock, flags);
}

static void queue_comp_task(struct ehca_cq *__cq)
{
	int cpu_id;
	struct ehca_cpu_comp_task *cct;
	int cq_jobs;
	unsigned long flags;

	cpu_id = find_next_online_cpu(pool);
	BUG_ON(!cpu_online(cpu_id));

	cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu_id);
	BUG_ON(!cct);

	spin_lock_irqsave(&cct->task_lock, flags);
	cq_jobs = cct->cq_jobs;
	spin_unlock_irqrestore(&cct->task_lock, flags);
	if (cq_jobs > 0) {
		cpu_id = find_next_online_cpu(pool);
		cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu_id);
		BUG_ON(!cct);
	}

	__queue_comp_task(__cq, cct);
}

static void run_comp_task(struct ehca_cpu_comp_task *cct)
{
	struct ehca_cq *cq;
	unsigned long flags;

	spin_lock_irqsave(&cct->task_lock, flags);

	while (!list_empty(&cct->cq_list)) {
		cq = list_entry(cct->cq_list.next, struct ehca_cq, entry);
		spin_unlock_irqrestore(&cct->task_lock, flags);

		comp_event_callback(cq);
		if (atomic_dec_and_test(&cq->nr_events))
			wake_up(&cq->wait_completion);

		spin_lock_irqsave(&cct->task_lock, flags);
		spin_lock(&cq->task_lock);
		cq->nr_callbacks--;
		if (!cq->nr_callbacks) {
			list_del_init(cct->cq_list.next);
			cct->cq_jobs--;
		}
		spin_unlock(&cq->task_lock);
	}

	spin_unlock_irqrestore(&cct->task_lock, flags);
}

static int comp_task(void *__cct)
{
	struct ehca_cpu_comp_task *cct = __cct;
	int cql_empty;
	DECLARE_WAITQUEUE(wait, current);

	set_current_state(TASK_INTERRUPTIBLE);
	while (!kthread_should_stop()) {
		add_wait_queue(&cct->wait_queue, &wait);

		spin_lock_irq(&cct->task_lock);
		cql_empty = list_empty(&cct->cq_list);
		spin_unlock_irq(&cct->task_lock);
		if (cql_empty)
			schedule();
		else
			__set_current_state(TASK_RUNNING);

		remove_wait_queue(&cct->wait_queue, &wait);

		spin_lock_irq(&cct->task_lock);
		cql_empty = list_empty(&cct->cq_list);
		spin_unlock_irq(&cct->task_lock);
		if (!cql_empty)
			run_comp_task(__cct);

		set_current_state(TASK_INTERRUPTIBLE);
	}
	__set_current_state(TASK_RUNNING);

	return 0;
}

static struct task_struct *create_comp_task(struct ehca_comp_pool *pool,
					    int cpu)
{
	struct ehca_cpu_comp_task *cct;

	cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
	spin_lock_init(&cct->task_lock);
	INIT_LIST_HEAD(&cct->cq_list);
	init_waitqueue_head(&cct->wait_queue);
	cct->task = kthread_create_on_node(comp_task, cct, cpu_to_node(cpu),
					   "ehca_comp/%d", cpu);

	return cct->task;
}

static void destroy_comp_task(struct ehca_comp_pool *pool,
			      int cpu)
{
	struct ehca_cpu_comp_task *cct;
	struct task_struct *task;
	unsigned long flags_cct;

	cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);

	spin_lock_irqsave(&cct->task_lock, flags_cct);

	task = cct->task;
	cct->task = NULL;
	cct->cq_jobs = 0;

	spin_unlock_irqrestore(&cct->task_lock, flags_cct);

	if (task)
		kthread_stop(task);
}

static void __cpuinit take_over_work(struct ehca_comp_pool *pool, int cpu)
{
	struct ehca_cpu_comp_task *cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
	LIST_HEAD(list);
	struct ehca_cq *cq;
	unsigned long flags_cct;

	spin_lock_irqsave(&cct->task_lock, flags_cct);

	list_splice_init(&cct->cq_list, &list);

	while (!list_empty(&list)) {
		cq = list_entry(cct->cq_list.next, struct ehca_cq, entry);

		list_del(&cq->entry);
		__queue_comp_task(cq, this_cpu_ptr(pool->cpu_comp_tasks));
	}

	spin_unlock_irqrestore(&cct->task_lock, flags_cct);

}

static int __cpuinit comp_pool_callback(struct notifier_block *nfb,
					unsigned long action,
					void *hcpu)
{
	unsigned int cpu = (unsigned long)hcpu;
	struct ehca_cpu_comp_task *cct;

	switch (action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
		ehca_gen_dbg("CPU: %x (CPU_PREPARE)", cpu);
		if (!create_comp_task(pool, cpu)) {
			ehca_gen_err("Can't create comp_task for cpu: %x", cpu);
			return notifier_from_errno(-ENOMEM);
		}
		break;
	case CPU_UP_CANCELED:
	case CPU_UP_CANCELED_FROZEN:
		ehca_gen_dbg("CPU: %x (CPU_CANCELED)", cpu);
		cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
		kthread_bind(cct->task, cpumask_any(cpu_online_mask));
		destroy_comp_task(pool, cpu);
		break;
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
		ehca_gen_dbg("CPU: %x (CPU_ONLINE)", cpu);
		cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
		kthread_bind(cct->task, cpu);
		wake_up_process(cct->task);
		break;
	case CPU_DOWN_PREPARE:
	case CPU_DOWN_PREPARE_FROZEN:
		ehca_gen_dbg("CPU: %x (CPU_DOWN_PREPARE)", cpu);
		break;
	case CPU_DOWN_FAILED:
	case CPU_DOWN_FAILED_FROZEN:
		ehca_gen_dbg("CPU: %x (CPU_DOWN_FAILED)", cpu);
		break;
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		ehca_gen_dbg("CPU: %x (CPU_DEAD)", cpu);
		destroy_comp_task(pool, cpu);
		take_over_work(pool, cpu);
		break;
	}

	return NOTIFY_OK;
}

static struct notifier_block comp_pool_callback_nb __cpuinitdata = {
	.notifier_call	= comp_pool_callback,
	.priority	= 0,
};

int ehca_create_comp_pool(void)
{
	int cpu;
	struct task_struct *task;

	if (!ehca_scaling_code)
		return 0;

	pool = kzalloc(sizeof(struct ehca_comp_pool), GFP_KERNEL);
	if (pool == NULL)
		return -ENOMEM;

	spin_lock_init(&pool->last_cpu_lock);
	pool->last_cpu = cpumask_any(cpu_online_mask);

	pool->cpu_comp_tasks = alloc_percpu(struct ehca_cpu_comp_task);
	if (pool->cpu_comp_tasks == NULL) {
		kfree(pool);
		return -EINVAL;
	}

	for_each_online_cpu(cpu) {
		task = create_comp_task(pool, cpu);
		if (task) {
			kthread_bind(task, cpu);
			wake_up_process(task);
		}
	}

	register_hotcpu_notifier(&comp_pool_callback_nb);

	printk(KERN_INFO "eHCA scaling code enabled\n");

	return 0;
}

void ehca_destroy_comp_pool(void)
{
	int i;

	if (!ehca_scaling_code)
		return;

	unregister_hotcpu_notifier(&comp_pool_callback_nb);

	for_each_online_cpu(i)
		destroy_comp_task(pool, i);

	free_percpu(pool->cpu_comp_tasks);
	kfree(pool);
}