summaryrefslogtreecommitdiff
path: root/drivers/net/wireless/intel/iwlwifi/dvm/scan.c
blob: 1d8590046ff7d8a8dd174f3616a5cd0c19cf251b (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
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
 *
 * Copyright(c) 2008 - 2014 Intel Corporation. All rights reserved.
 * Copyright(c) 2018        Intel Corporation
 *
 * Contact Information:
 *  Intel Linux Wireless <linuxwifi@intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *****************************************************************************/
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/etherdevice.h>
#include <net/mac80211.h>

#include "dev.h"
#include "agn.h"

/* For active scan, listen ACTIVE_DWELL_TIME (msec) on each channel after
 * sending probe req.  This should be set long enough to hear probe responses
 * from more than one AP.  */
#define IWL_ACTIVE_DWELL_TIME_24    (30)       /* all times in msec */
#define IWL_ACTIVE_DWELL_TIME_52    (20)

#define IWL_ACTIVE_DWELL_FACTOR_24GHZ (3)
#define IWL_ACTIVE_DWELL_FACTOR_52GHZ (2)

/* For passive scan, listen PASSIVE_DWELL_TIME (msec) on each channel.
 * Must be set longer than active dwell time.
 * For the most reliable scan, set > AP beacon interval (typically 100msec). */
#define IWL_PASSIVE_DWELL_TIME_24   (20)       /* all times in msec */
#define IWL_PASSIVE_DWELL_TIME_52   (10)
#define IWL_PASSIVE_DWELL_BASE      (100)
#define IWL_CHANNEL_TUNE_TIME       5
#define MAX_SCAN_CHANNEL	    50

/* For reset radio, need minimal dwell time only */
#define IWL_RADIO_RESET_DWELL_TIME	5

static int iwl_send_scan_abort(struct iwl_priv *priv)
{
	int ret;
	struct iwl_host_cmd cmd = {
		.id = REPLY_SCAN_ABORT_CMD,
		.flags = CMD_WANT_SKB,
	};
	__le32 *status;

	/* Exit instantly with error when device is not ready
	 * to receive scan abort command or it does not perform
	 * hardware scan currently */
	if (!test_bit(STATUS_READY, &priv->status) ||
	    !test_bit(STATUS_SCAN_HW, &priv->status) ||
	    test_bit(STATUS_FW_ERROR, &priv->status))
		return -EIO;

	ret = iwl_dvm_send_cmd(priv, &cmd);
	if (ret)
		return ret;

	status = (void *)cmd.resp_pkt->data;
	if (*status != CAN_ABORT_STATUS) {
		/* The scan abort will return 1 for success or
		 * 2 for "failure".  A failure condition can be
		 * due to simply not being in an active scan which
		 * can occur if we send the scan abort before we
		 * the microcode has notified us that a scan is
		 * completed. */
		IWL_DEBUG_SCAN(priv, "SCAN_ABORT ret %d.\n",
			       le32_to_cpu(*status));
		ret = -EIO;
	}

	iwl_free_resp(&cmd);
	return ret;
}

static void iwl_complete_scan(struct iwl_priv *priv, bool aborted)
{
	struct cfg80211_scan_info info = {
		.aborted = aborted,
	};

	/* check if scan was requested from mac80211 */
	if (priv->scan_request) {
		IWL_DEBUG_SCAN(priv, "Complete scan in mac80211\n");
		ieee80211_scan_completed(priv->hw, &info);
	}

	priv->scan_type = IWL_SCAN_NORMAL;
	priv->scan_vif = NULL;
	priv->scan_request = NULL;
}

static void iwl_process_scan_complete(struct iwl_priv *priv)
{
	bool aborted;

	lockdep_assert_held(&priv->mutex);

	if (!test_and_clear_bit(STATUS_SCAN_COMPLETE, &priv->status))
		return;

	IWL_DEBUG_SCAN(priv, "Completed scan.\n");

	cancel_delayed_work(&priv->scan_check);

	aborted = test_and_clear_bit(STATUS_SCAN_ABORTING, &priv->status);
	if (aborted)
		IWL_DEBUG_SCAN(priv, "Aborted scan completed.\n");

	if (!test_and_clear_bit(STATUS_SCANNING, &priv->status)) {
		IWL_DEBUG_SCAN(priv, "Scan already completed.\n");
		goto out_settings;
	}

	if (priv->scan_type != IWL_SCAN_NORMAL && !aborted) {
		int err;

		/* Check if mac80211 requested scan during our internal scan */
		if (priv->scan_request == NULL)
			goto out_complete;

		/* If so request a new scan */
		err = iwl_scan_initiate(priv, priv->scan_vif, IWL_SCAN_NORMAL,
					priv->scan_request->channels[0]->band);
		if (err) {
			IWL_DEBUG_SCAN(priv,
				"failed to initiate pending scan: %d\n", err);
			aborted = true;
			goto out_complete;
		}

		return;
	}

out_complete:
	iwl_complete_scan(priv, aborted);

out_settings:
	/* Can we still talk to firmware ? */
	if (!iwl_is_ready_rf(priv))
		return;

	iwlagn_post_scan(priv);
}

void iwl_force_scan_end(struct iwl_priv *priv)
{
	lockdep_assert_held(&priv->mutex);

	if (!test_bit(STATUS_SCANNING, &priv->status)) {
		IWL_DEBUG_SCAN(priv, "Forcing scan end while not scanning\n");
		return;
	}

	IWL_DEBUG_SCAN(priv, "Forcing scan end\n");
	clear_bit(STATUS_SCANNING, &priv->status);
	clear_bit(STATUS_SCAN_HW, &priv->status);
	clear_bit(STATUS_SCAN_ABORTING, &priv->status);
	clear_bit(STATUS_SCAN_COMPLETE, &priv->status);
	iwl_complete_scan(priv, true);
}

static void iwl_do_scan_abort(struct iwl_priv *priv)
{
	int ret;

	lockdep_assert_held(&priv->mutex);

	if (!test_bit(STATUS_SCANNING, &priv->status)) {
		IWL_DEBUG_SCAN(priv, "Not performing scan to abort\n");
		return;
	}

	if (test_and_set_bit(STATUS_SCAN_ABORTING, &priv->status)) {
		IWL_DEBUG_SCAN(priv, "Scan abort in progress\n");
		return;
	}

	ret = iwl_send_scan_abort(priv);
	if (ret) {
		IWL_DEBUG_SCAN(priv, "Send scan abort failed %d\n", ret);
		iwl_force_scan_end(priv);
	} else
		IWL_DEBUG_SCAN(priv, "Successfully send scan abort\n");
}

/**
 * iwl_scan_cancel - Cancel any currently executing HW scan
 */
int iwl_scan_cancel(struct iwl_priv *priv)
{
	IWL_DEBUG_SCAN(priv, "Queuing abort scan\n");
	queue_work(priv->workqueue, &priv->abort_scan);
	return 0;
}

/**
 * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
 * @ms: amount of time to wait (in milliseconds) for scan to abort
 *
 */
void iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
{
	unsigned long timeout = jiffies + msecs_to_jiffies(ms);

	lockdep_assert_held(&priv->mutex);

	IWL_DEBUG_SCAN(priv, "Scan cancel timeout\n");

	iwl_do_scan_abort(priv);

	while (time_before_eq(jiffies, timeout)) {
		if (!test_bit(STATUS_SCAN_HW, &priv->status))
			goto finished;
		msleep(20);
	}

	return;

 finished:
	/*
	 * Now STATUS_SCAN_HW is clear. This means that the
	 * device finished, but the background work is going
	 * to execute at best as soon as we release the mutex.
	 * Since we need to be able to issue a new scan right
	 * after this function returns, run the complete here.
	 * The STATUS_SCAN_COMPLETE bit will then be cleared
	 * and prevent the background work from "completing"
	 * a possible new scan.
	 */
	iwl_process_scan_complete(priv);
}

/* Service response to REPLY_SCAN_CMD (0x80) */
static void iwl_rx_reply_scan(struct iwl_priv *priv,
			      struct iwl_rx_cmd_buffer *rxb)
{
#ifdef CONFIG_IWLWIFI_DEBUG
	struct iwl_rx_packet *pkt = rxb_addr(rxb);
	struct iwl_scanreq_notification *notif = (void *)pkt->data;

	IWL_DEBUG_SCAN(priv, "Scan request status = 0x%x\n", notif->status);
#endif
}

/* Service SCAN_START_NOTIFICATION (0x82) */
static void iwl_rx_scan_start_notif(struct iwl_priv *priv,
				    struct iwl_rx_cmd_buffer *rxb)
{
	struct iwl_rx_packet *pkt = rxb_addr(rxb);
	struct iwl_scanstart_notification *notif = (void *)pkt->data;

	priv->scan_start_tsf = le32_to_cpu(notif->tsf_low);
	IWL_DEBUG_SCAN(priv, "Scan start: "
		       "%d [802.11%s] "
		       "(TSF: 0x%08X:%08X) - %d (beacon timer %u)\n",
		       notif->channel,
		       notif->band ? "bg" : "a",
		       le32_to_cpu(notif->tsf_high),
		       le32_to_cpu(notif->tsf_low),
		       notif->status, notif->beacon_timer);
}

/* Service SCAN_RESULTS_NOTIFICATION (0x83) */
static void iwl_rx_scan_results_notif(struct iwl_priv *priv,
				      struct iwl_rx_cmd_buffer *rxb)
{
#ifdef CONFIG_IWLWIFI_DEBUG
	struct iwl_rx_packet *pkt = rxb_addr(rxb);
	struct iwl_scanresults_notification *notif = (void *)pkt->data;

	IWL_DEBUG_SCAN(priv, "Scan ch.res: "
		       "%d [802.11%s] "
		       "probe status: %u:%u "
		       "(TSF: 0x%08X:%08X) - %d "
		       "elapsed=%lu usec\n",
		       notif->channel,
		       notif->band ? "bg" : "a",
		       notif->probe_status, notif->num_probe_not_sent,
		       le32_to_cpu(notif->tsf_high),
		       le32_to_cpu(notif->tsf_low),
		       le32_to_cpu(notif->statistics[0]),
		       le32_to_cpu(notif->tsf_low) - priv->scan_start_tsf);
#endif
}

/* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
static void iwl_rx_scan_complete_notif(struct iwl_priv *priv,
				       struct iwl_rx_cmd_buffer *rxb)
{
	struct iwl_rx_packet *pkt = rxb_addr(rxb);
	struct iwl_scancomplete_notification *scan_notif = (void *)pkt->data;

	IWL_DEBUG_SCAN(priv, "Scan complete: %d channels (TSF 0x%08X:%08X) - %d\n",
		       scan_notif->scanned_channels,
		       scan_notif->tsf_low,
		       scan_notif->tsf_high, scan_notif->status);

	IWL_DEBUG_SCAN(priv, "Scan on %sGHz took %dms\n",
		       (priv->scan_band == NL80211_BAND_2GHZ) ? "2.4" : "5.2",
		       jiffies_to_msecs(jiffies - priv->scan_start));

	/*
	 * When aborting, we run the scan completed background work inline
	 * and the background work must then do nothing. The SCAN_COMPLETE
	 * bit helps implement that logic and thus needs to be set before
	 * queueing the work. Also, since the scan abort waits for SCAN_HW
	 * to clear, we need to set SCAN_COMPLETE before clearing SCAN_HW
	 * to avoid a race there.
	 */
	set_bit(STATUS_SCAN_COMPLETE, &priv->status);
	clear_bit(STATUS_SCAN_HW, &priv->status);
	queue_work(priv->workqueue, &priv->scan_completed);

	if (priv->iw_mode != NL80211_IFTYPE_ADHOC &&
	    iwl_advanced_bt_coexist(priv) &&
	    priv->bt_status != scan_notif->bt_status) {
		if (scan_notif->bt_status) {
			/* BT on */
			if (!priv->bt_ch_announce)
				priv->bt_traffic_load =
					IWL_BT_COEX_TRAFFIC_LOAD_HIGH;
			/*
			 * otherwise, no traffic load information provided
			 * no changes made
			 */
		} else {
			/* BT off */
			priv->bt_traffic_load =
				IWL_BT_COEX_TRAFFIC_LOAD_NONE;
		}
		priv->bt_status = scan_notif->bt_status;
		queue_work(priv->workqueue,
			   &priv->bt_traffic_change_work);
	}
}

void iwl_setup_rx_scan_handlers(struct iwl_priv *priv)
{
	/* scan handlers */
	priv->rx_handlers[REPLY_SCAN_CMD] = iwl_rx_reply_scan;
	priv->rx_handlers[SCAN_START_NOTIFICATION] = iwl_rx_scan_start_notif;
	priv->rx_handlers[SCAN_RESULTS_NOTIFICATION] =
					iwl_rx_scan_results_notif;
	priv->rx_handlers[SCAN_COMPLETE_NOTIFICATION] =
					iwl_rx_scan_complete_notif;
}

static u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
				     enum nl80211_band band, u8 n_probes)
{
	if (band == NL80211_BAND_5GHZ)
		return IWL_ACTIVE_DWELL_TIME_52 +
			IWL_ACTIVE_DWELL_FACTOR_52GHZ * (n_probes + 1);
	else
		return IWL_ACTIVE_DWELL_TIME_24 +
			IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
}

static u16 iwl_limit_dwell(struct iwl_priv *priv, u16 dwell_time)
{
	struct iwl_rxon_context *ctx;
	int limits[NUM_IWL_RXON_CTX] = {};
	int n_active = 0;
	u16 limit;

	BUILD_BUG_ON(NUM_IWL_RXON_CTX != 2);

	/*
	 * If we're associated, we clamp the dwell time 98%
	 * of the beacon interval (minus 2 * channel tune time)
	 * If both contexts are active, we have to restrict to
	 * 1/2 of the minimum of them, because they might be in
	 * lock-step with the time inbetween only half of what
	 * time we'd have in each of them.
	 */
	for_each_context(priv, ctx) {
		switch (ctx->staging.dev_type) {
		case RXON_DEV_TYPE_P2P:
			/* no timing constraints */
			continue;
		case RXON_DEV_TYPE_ESS:
		default:
			/* timing constraints if associated */
			if (!iwl_is_associated_ctx(ctx))
				continue;
			break;
		case RXON_DEV_TYPE_CP:
		case RXON_DEV_TYPE_2STA:
			/*
			 * These seem to always have timers for TBTT
			 * active in uCode even when not associated yet.
			 */
			break;
		}

		limits[n_active++] = ctx->beacon_int ?: IWL_PASSIVE_DWELL_BASE;
	}

	switch (n_active) {
	case 0:
		return dwell_time;
	case 2:
		limit = (limits[1] * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
		limit /= 2;
		dwell_time = min(limit, dwell_time);
		/* fall through */
	case 1:
		limit = (limits[0] * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
		limit /= n_active;
		return min(limit, dwell_time);
	default:
		WARN_ON_ONCE(1);
		return dwell_time;
	}
}

static u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
				      enum nl80211_band band)
{
	u16 passive = (band == NL80211_BAND_2GHZ) ?
	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;

	return iwl_limit_dwell(priv, passive);
}

/* Return valid, unused, channel for a passive scan to reset the RF */
static u8 iwl_get_single_channel_number(struct iwl_priv *priv,
					enum nl80211_band band)
{
	struct ieee80211_supported_band *sband = priv->hw->wiphy->bands[band];
	struct iwl_rxon_context *ctx;
	int i;

	for (i = 0; i < sband->n_channels; i++) {
		bool busy = false;

		for_each_context(priv, ctx) {
			busy = sband->channels[i].hw_value ==
				le16_to_cpu(ctx->staging.channel);
			if (busy)
				break;
		}

		if (busy)
			continue;

		if (!(sband->channels[i].flags & IEEE80211_CHAN_DISABLED))
			return sband->channels[i].hw_value;
	}

	return 0;
}

static int iwl_get_channel_for_reset_scan(struct iwl_priv *priv,
					  struct ieee80211_vif *vif,
					  enum nl80211_band band,
					  struct iwl_scan_channel *scan_ch)
{
	const struct ieee80211_supported_band *sband;
	u16 channel;

	sband = iwl_get_hw_mode(priv, band);
	if (!sband) {
		IWL_ERR(priv, "invalid band\n");
		return 0;
	}

	channel = iwl_get_single_channel_number(priv, band);
	if (channel) {
		scan_ch->channel = cpu_to_le16(channel);
		scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
		scan_ch->active_dwell =
			cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
		scan_ch->passive_dwell =
			cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
		/* Set txpower levels to defaults */
		scan_ch->dsp_atten = 110;
		if (band == NL80211_BAND_5GHZ)
			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
		else
			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
		return 1;
	}

	IWL_ERR(priv, "no valid channel found\n");
	return 0;
}

static int iwl_get_channels_for_scan(struct iwl_priv *priv,
				     struct ieee80211_vif *vif,
				     enum nl80211_band band,
				     u8 is_active, u8 n_probes,
				     struct iwl_scan_channel *scan_ch)
{
	struct ieee80211_channel *chan;
	const struct ieee80211_supported_band *sband;
	u16 passive_dwell = 0;
	u16 active_dwell = 0;
	int added, i;
	u16 channel;

	sband = iwl_get_hw_mode(priv, band);
	if (!sband)
		return 0;

	active_dwell = iwl_get_active_dwell_time(priv, band, n_probes);
	passive_dwell = iwl_get_passive_dwell_time(priv, band);

	if (passive_dwell <= active_dwell)
		passive_dwell = active_dwell + 1;

	for (i = 0, added = 0; i < priv->scan_request->n_channels; i++) {
		chan = priv->scan_request->channels[i];

		if (chan->band != band)
			continue;

		channel = chan->hw_value;
		scan_ch->channel = cpu_to_le16(channel);

		if (!is_active || (chan->flags & IEEE80211_CHAN_NO_IR))
			scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
		else
			scan_ch->type = SCAN_CHANNEL_TYPE_ACTIVE;

		if (n_probes)
			scan_ch->type |= IWL_SCAN_PROBE_MASK(n_probes);

		scan_ch->active_dwell = cpu_to_le16(active_dwell);
		scan_ch->passive_dwell = cpu_to_le16(passive_dwell);

		/* Set txpower levels to defaults */
		scan_ch->dsp_atten = 110;

		/* NOTE: if we were doing 6Mb OFDM for scans we'd use
		 * power level:
		 * scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
		 */
		if (band == NL80211_BAND_5GHZ)
			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
		else
			scan_ch->tx_gain = ((1 << 5) | (5 << 3));

		IWL_DEBUG_SCAN(priv, "Scanning ch=%d prob=0x%X [%s %d]\n",
			       channel, le32_to_cpu(scan_ch->type),
			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
				"ACTIVE" : "PASSIVE",
			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
			       active_dwell : passive_dwell);

		scan_ch++;
		added++;
	}

	IWL_DEBUG_SCAN(priv, "total channels to scan %d\n", added);
	return added;
}

/**
 * iwl_fill_probe_req - fill in all required fields and IE for probe request
 */

static u16 iwl_fill_probe_req(struct ieee80211_mgmt *frame, const u8 *ta,
			      const u8 *ies, int ie_len, const u8 *ssid,
			      u8 ssid_len, int left)
{
	int len = 0;
	u8 *pos = NULL;

	/* Make sure there is enough space for the probe request,
	 * two mandatory IEs and the data */
	left -= 24;
	if (left < 0)
		return 0;

	frame->frame_control = cpu_to_le16(IEEE80211_STYPE_PROBE_REQ);
	eth_broadcast_addr(frame->da);
	memcpy(frame->sa, ta, ETH_ALEN);
	eth_broadcast_addr(frame->bssid);
	frame->seq_ctrl = 0;

	len += 24;

	/* ...next IE... */
	pos = &frame->u.probe_req.variable[0];

	/* fill in our SSID IE */
	left -= ssid_len + 2;
	if (left < 0)
		return 0;
	*pos++ = WLAN_EID_SSID;
	*pos++ = ssid_len;
	if (ssid && ssid_len) {
		memcpy(pos, ssid, ssid_len);
		pos += ssid_len;
	}

	len += ssid_len + 2;

	if (WARN_ON(left < ie_len))
		return len;

	if (ies && ie_len) {
		memcpy(pos, ies, ie_len);
		len += ie_len;
	}

	return (u16)len;
}

static int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
{
	struct iwl_host_cmd cmd = {
		.id = REPLY_SCAN_CMD,
		.len = { sizeof(struct iwl_scan_cmd), },
	};
	struct iwl_scan_cmd *scan;
	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
	u32 rate_flags = 0;
	u16 cmd_len = 0;
	u16 rx_chain = 0;
	enum nl80211_band band;
	u8 n_probes = 0;
	u8 rx_ant = priv->nvm_data->valid_rx_ant;
	u8 rate;
	bool is_active = false;
	int  chan_mod;
	u8 active_chains;
	u8 scan_tx_antennas = priv->nvm_data->valid_tx_ant;
	int ret;
	int scan_cmd_size = sizeof(struct iwl_scan_cmd) +
			    MAX_SCAN_CHANNEL * sizeof(struct iwl_scan_channel) +
			    priv->fw->ucode_capa.max_probe_length;
	const u8 *ssid = NULL;
	u8 ssid_len = 0;

	if (WARN_ON(priv->scan_type == IWL_SCAN_NORMAL &&
		    (!priv->scan_request ||
		     priv->scan_request->n_channels > MAX_SCAN_CHANNEL)))
		return -EINVAL;

	lockdep_assert_held(&priv->mutex);

	if (vif)
		ctx = iwl_rxon_ctx_from_vif(vif);

	if (!priv->scan_cmd) {
		priv->scan_cmd = kmalloc(scan_cmd_size, GFP_KERNEL);
		if (!priv->scan_cmd) {
			IWL_DEBUG_SCAN(priv,
				       "fail to allocate memory for scan\n");
			return -ENOMEM;
		}
	}
	scan = priv->scan_cmd;
	memset(scan, 0, scan_cmd_size);

	scan->quiet_plcp_th = IWL_PLCP_QUIET_THRESH;
	scan->quiet_time = IWL_ACTIVE_QUIET_TIME;

	if (iwl_is_any_associated(priv)) {
		u16 interval = 0;
		u32 extra;
		u32 suspend_time = 100;
		u32 scan_suspend_time = 100;

		IWL_DEBUG_INFO(priv, "Scanning while associated...\n");
		switch (priv->scan_type) {
		case IWL_SCAN_RADIO_RESET:
			interval = 0;
			break;
		case IWL_SCAN_NORMAL:
			interval = vif->bss_conf.beacon_int;
			break;
		}

		scan->suspend_time = 0;
		scan->max_out_time = cpu_to_le32(200 * 1024);
		if (!interval)
			interval = suspend_time;

		extra = (suspend_time / interval) << 22;
		scan_suspend_time = (extra |
		    ((suspend_time % interval) * 1024));
		scan->suspend_time = cpu_to_le32(scan_suspend_time);
		IWL_DEBUG_SCAN(priv, "suspend_time 0x%X beacon interval %d\n",
			       scan_suspend_time, interval);
	}

	switch (priv->scan_type) {
	case IWL_SCAN_RADIO_RESET:
		IWL_DEBUG_SCAN(priv, "Start internal passive scan.\n");
		/*
		 * Override quiet time as firmware checks that active
		 * dwell is >= quiet; since we use passive scan it'll
		 * not actually be used.
		 */
		scan->quiet_time = cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
		break;
	case IWL_SCAN_NORMAL:
		if (priv->scan_request->n_ssids) {
			int i, p = 0;
			IWL_DEBUG_SCAN(priv, "Kicking off active scan\n");
			/*
			 * The highest priority SSID is inserted to the
			 * probe request template.
			 */
			ssid_len = priv->scan_request->ssids[0].ssid_len;
			ssid = priv->scan_request->ssids[0].ssid;

			/*
			 * Invert the order of ssids, the firmware will invert
			 * it back.
			 */
			for (i = priv->scan_request->n_ssids - 1; i >= 1; i--) {
				scan->direct_scan[p].id = WLAN_EID_SSID;
				scan->direct_scan[p].len =
					priv->scan_request->ssids[i].ssid_len;
				memcpy(scan->direct_scan[p].ssid,
				       priv->scan_request->ssids[i].ssid,
				       priv->scan_request->ssids[i].ssid_len);
				n_probes++;
				p++;
			}
			is_active = true;
		} else
			IWL_DEBUG_SCAN(priv, "Start passive scan.\n");
		break;
	}

	scan->tx_cmd.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK;
	scan->tx_cmd.sta_id = ctx->bcast_sta_id;
	scan->tx_cmd.stop_time.life_time = TX_CMD_LIFE_TIME_INFINITE;

	switch (priv->scan_band) {
	case NL80211_BAND_2GHZ:
		scan->flags = RXON_FLG_BAND_24G_MSK | RXON_FLG_AUTO_DETECT_MSK;
		chan_mod = le32_to_cpu(
			priv->contexts[IWL_RXON_CTX_BSS].active.flags &
						RXON_FLG_CHANNEL_MODE_MSK)
				       >> RXON_FLG_CHANNEL_MODE_POS;
		if ((priv->scan_request && priv->scan_request->no_cck) ||
		    chan_mod == CHANNEL_MODE_PURE_40) {
			rate = IWL_RATE_6M_PLCP;
		} else {
			rate = IWL_RATE_1M_PLCP;
			rate_flags = RATE_MCS_CCK_MSK;
		}
		/*
		 * Internal scans are passive, so we can indiscriminately set
		 * the BT ignore flag on 2.4 GHz since it applies to TX only.
		 */
		if (priv->lib->bt_params &&
		    priv->lib->bt_params->advanced_bt_coexist)
			scan->tx_cmd.tx_flags |= TX_CMD_FLG_IGNORE_BT;
		break;
	case NL80211_BAND_5GHZ:
		rate = IWL_RATE_6M_PLCP;
		break;
	default:
		IWL_WARN(priv, "Invalid scan band\n");
		return -EIO;
	}

	/*
	 * If active scanning is requested but a certain channel is
	 * marked passive, we can do active scanning if we detect
	 * transmissions.
	 *
	 * There is an issue with some firmware versions that triggers
	 * a sysassert on a "good CRC threshold" of zero (== disabled),
	 * on a radar channel even though this means that we should NOT
	 * send probes.
	 *
	 * The "good CRC threshold" is the number of frames that we
	 * need to receive during our dwell time on a channel before
	 * sending out probes -- setting this to a huge value will
	 * mean we never reach it, but at the same time work around
	 * the aforementioned issue. Thus use IWL_GOOD_CRC_TH_NEVER
	 * here instead of IWL_GOOD_CRC_TH_DISABLED.
	 *
	 * This was fixed in later versions along with some other
	 * scan changes, and the threshold behaves as a flag in those
	 * versions.
	 */
	if (priv->new_scan_threshold_behaviour)
		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
						IWL_GOOD_CRC_TH_DISABLED;
	else
		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
						IWL_GOOD_CRC_TH_NEVER;

	band = priv->scan_band;

	if (band == NL80211_BAND_2GHZ &&
	    priv->lib->bt_params &&
	    priv->lib->bt_params->advanced_bt_coexist) {
		/* transmit 2.4 GHz probes only on first antenna */
		scan_tx_antennas = first_antenna(scan_tx_antennas);
	}

	priv->scan_tx_ant[band] = iwl_toggle_tx_ant(priv,
						    priv->scan_tx_ant[band],
						    scan_tx_antennas);
	rate_flags |= iwl_ant_idx_to_flags(priv->scan_tx_ant[band]);
	scan->tx_cmd.rate_n_flags = iwl_hw_set_rate_n_flags(rate, rate_flags);

	/*
	 * In power save mode while associated use one chain,
	 * otherwise use all chains
	 */
	if (test_bit(STATUS_POWER_PMI, &priv->status) &&
	    !(priv->hw->conf.flags & IEEE80211_CONF_IDLE)) {
		/* rx_ant has been set to all valid chains previously */
		active_chains = rx_ant &
				((u8)(priv->chain_noise_data.active_chains));
		if (!active_chains)
			active_chains = rx_ant;

		IWL_DEBUG_SCAN(priv, "chain_noise_data.active_chains: %u\n",
				priv->chain_noise_data.active_chains);

		rx_ant = first_antenna(active_chains);
	}
	if (priv->lib->bt_params &&
	    priv->lib->bt_params->advanced_bt_coexist &&
	    priv->bt_full_concurrent) {
		/* operated as 1x1 in full concurrency mode */
		rx_ant = first_antenna(rx_ant);
	}

	/* MIMO is not used here, but value is required */
	rx_chain |=
		priv->nvm_data->valid_rx_ant << RXON_RX_CHAIN_VALID_POS;
	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_MIMO_SEL_POS;
	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_SEL_POS;
	rx_chain |= 0x1 << RXON_RX_CHAIN_DRIVER_FORCE_POS;
	scan->rx_chain = cpu_to_le16(rx_chain);
	switch (priv->scan_type) {
	case IWL_SCAN_NORMAL:
		cmd_len = iwl_fill_probe_req(
					(struct ieee80211_mgmt *)scan->data,
					vif->addr,
					priv->scan_request->ie,
					priv->scan_request->ie_len,
					ssid, ssid_len,
					scan_cmd_size - sizeof(*scan));
		break;
	case IWL_SCAN_RADIO_RESET:
		/* use bcast addr, will not be transmitted but must be valid */
		cmd_len = iwl_fill_probe_req(
					(struct ieee80211_mgmt *)scan->data,
					iwl_bcast_addr, NULL, 0,
					NULL, 0,
					scan_cmd_size - sizeof(*scan));
		break;
	default:
		BUG();
	}
	scan->tx_cmd.len = cpu_to_le16(cmd_len);

	scan->filter_flags |= (RXON_FILTER_ACCEPT_GRP_MSK |
			       RXON_FILTER_BCON_AWARE_MSK);

	switch (priv->scan_type) {
	case IWL_SCAN_RADIO_RESET:
		scan->channel_count =
			iwl_get_channel_for_reset_scan(priv, vif, band,
				(void *)&scan->data[cmd_len]);
		break;
	case IWL_SCAN_NORMAL:
		scan->channel_count =
			iwl_get_channels_for_scan(priv, vif, band,
				is_active, n_probes,
				(void *)&scan->data[cmd_len]);
		break;
	}

	if (scan->channel_count == 0) {
		IWL_DEBUG_SCAN(priv, "channel count %d\n", scan->channel_count);
		return -EIO;
	}

	cmd.len[0] += le16_to_cpu(scan->tx_cmd.len) +
	    scan->channel_count * sizeof(struct iwl_scan_channel);
	cmd.data[0] = scan;
	cmd.dataflags[0] = IWL_HCMD_DFL_NOCOPY;
	scan->len = cpu_to_le16(cmd.len[0]);

	/* set scan bit here for PAN params */
	set_bit(STATUS_SCAN_HW, &priv->status);

	ret = iwlagn_set_pan_params(priv);
	if (ret) {
		clear_bit(STATUS_SCAN_HW, &priv->status);
		return ret;
	}

	ret = iwl_dvm_send_cmd(priv, &cmd);
	if (ret) {
		clear_bit(STATUS_SCAN_HW, &priv->status);
		iwlagn_set_pan_params(priv);
	}

	return ret;
}

void iwl_init_scan_params(struct iwl_priv *priv)
{
	u8 ant_idx = fls(priv->nvm_data->valid_tx_ant) - 1;
	if (!priv->scan_tx_ant[NL80211_BAND_5GHZ])
		priv->scan_tx_ant[NL80211_BAND_5GHZ] = ant_idx;
	if (!priv->scan_tx_ant[NL80211_BAND_2GHZ])
		priv->scan_tx_ant[NL80211_BAND_2GHZ] = ant_idx;
}

int __must_check iwl_scan_initiate(struct iwl_priv *priv,
				   struct ieee80211_vif *vif,
				   enum iwl_scan_type scan_type,
				   enum nl80211_band band)
{
	int ret;

	lockdep_assert_held(&priv->mutex);

	cancel_delayed_work(&priv->scan_check);

	if (!iwl_is_ready_rf(priv)) {
		IWL_WARN(priv, "Request scan called when driver not ready.\n");
		return -EIO;
	}

	if (test_bit(STATUS_SCAN_HW, &priv->status)) {
		IWL_DEBUG_SCAN(priv,
			"Multiple concurrent scan requests in parallel.\n");
		return -EBUSY;
	}

	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
		IWL_DEBUG_SCAN(priv, "Scan request while abort pending.\n");
		return -EBUSY;
	}

	IWL_DEBUG_SCAN(priv, "Starting %sscan...\n",
			scan_type == IWL_SCAN_NORMAL ? "" :
			"internal short ");

	set_bit(STATUS_SCANNING, &priv->status);
	priv->scan_type = scan_type;
	priv->scan_start = jiffies;
	priv->scan_band = band;

	ret = iwlagn_request_scan(priv, vif);
	if (ret) {
		clear_bit(STATUS_SCANNING, &priv->status);
		priv->scan_type = IWL_SCAN_NORMAL;
		return ret;
	}

	queue_delayed_work(priv->workqueue, &priv->scan_check,
			   IWL_SCAN_CHECK_WATCHDOG);

	return 0;
}


/*
 * internal short scan, this function should only been called while associated.
 * It will reset and tune the radio to prevent possible RF related problem
 */
void iwl_internal_short_hw_scan(struct iwl_priv *priv)
{
	queue_work(priv->workqueue, &priv->start_internal_scan);
}

static void iwl_bg_start_internal_scan(struct work_struct *work)
{
	struct iwl_priv *priv =
		container_of(work, struct iwl_priv, start_internal_scan);

	IWL_DEBUG_SCAN(priv, "Start internal scan\n");

	mutex_lock(&priv->mutex);

	if (priv->scan_type == IWL_SCAN_RADIO_RESET) {
		IWL_DEBUG_SCAN(priv, "Internal scan already in progress\n");
		goto unlock;
	}

	if (test_bit(STATUS_SCANNING, &priv->status)) {
		IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
		goto unlock;
	}

	if (iwl_scan_initiate(priv, NULL, IWL_SCAN_RADIO_RESET, priv->band))
		IWL_DEBUG_SCAN(priv, "failed to start internal short scan\n");
 unlock:
	mutex_unlock(&priv->mutex);
}

static void iwl_bg_scan_check(struct work_struct *data)
{
	struct iwl_priv *priv =
	    container_of(data, struct iwl_priv, scan_check.work);

	IWL_DEBUG_SCAN(priv, "Scan check work\n");

	/* Since we are here firmware does not finish scan and
	 * most likely is in bad shape, so we don't bother to
	 * send abort command, just force scan complete to mac80211 */
	mutex_lock(&priv->mutex);
	iwl_force_scan_end(priv);
	mutex_unlock(&priv->mutex);
}

static void iwl_bg_abort_scan(struct work_struct *work)
{
	struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);

	IWL_DEBUG_SCAN(priv, "Abort scan work\n");

	/* We keep scan_check work queued in case when firmware will not
	 * report back scan completed notification */
	mutex_lock(&priv->mutex);
	iwl_scan_cancel_timeout(priv, 200);
	mutex_unlock(&priv->mutex);
}

static void iwl_bg_scan_completed(struct work_struct *work)
{
	struct iwl_priv *priv =
		container_of(work, struct iwl_priv, scan_completed);

	mutex_lock(&priv->mutex);
	iwl_process_scan_complete(priv);
	mutex_unlock(&priv->mutex);
}

void iwl_setup_scan_deferred_work(struct iwl_priv *priv)
{
	INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed);
	INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
	INIT_WORK(&priv->start_internal_scan, iwl_bg_start_internal_scan);
	INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
}

void iwl_cancel_scan_deferred_work(struct iwl_priv *priv)
{
	cancel_work_sync(&priv->start_internal_scan);
	cancel_work_sync(&priv->abort_scan);
	cancel_work_sync(&priv->scan_completed);

	if (cancel_delayed_work_sync(&priv->scan_check)) {
		mutex_lock(&priv->mutex);
		iwl_force_scan_end(priv);
		mutex_unlock(&priv->mutex);
	}
}