aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/wireless/iwlwifi/iwl-scan.c
blob: c89365e2ca58e3f4c5d142e9f9d11ed75d7642cc (plain) (blame)
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
/******************************************************************************
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2008 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110,
 * USA
 *
 * The full GNU General Public License is included in this distribution
 * in the file called LICENSE.GPL.
 *
 * Contact Information:
 * Tomas Winkler <tomas.winkler@intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *****************************************************************************/
#include <net/mac80211.h>
#include <linux/etherdevice.h>

#include "iwl-eeprom.h"
#include "iwl-dev.h"
#include "iwl-core.h"
#include "iwl-sta.h"
#include "iwl-io.h"
#include "iwl-helpers.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 faster active scanning, scan will move to the next channel if fewer than
 * PLCP_QUIET_THRESH packets are heard on this channel within
 * ACTIVE_QUIET_TIME after sending probe request.  This shortens the dwell
 * time if it's a quiet channel (nothing responded to our probe, and there's
 * no other traffic).
 * Disable "quiet" feature by setting PLCP_QUIET_THRESH to 0. */
#define IWL_PLCP_QUIET_THRESH       __constant_cpu_to_le16(1)  /* packets */
#define IWL_ACTIVE_QUIET_TIME       __constant_cpu_to_le16(10)  /* msec */

/* 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 IWL_SCAN_PROBE_MASK(n) 	cpu_to_le32((BIT(n) | (BIT(n) - BIT(1))))


static int scan_tx_ant[3] = {
	RATE_MCS_ANT_A_MSK, RATE_MCS_ANT_B_MSK, RATE_MCS_ANT_C_MSK
};



static int iwl_is_empty_essid(const char *essid, int essid_len)
{
	/* Single white space is for Linksys APs */
	if (essid_len == 1 && essid[0] == ' ')
		return 1;

	/* Otherwise, if the entire essid is 0, we assume it is hidden */
	while (essid_len) {
		essid_len--;
		if (essid[essid_len] != '\0')
			return 0;
	}

	return 1;
}



static const char *iwl_escape_essid(const char *essid, u8 essid_len)
{
	static char escaped[IW_ESSID_MAX_SIZE * 2 + 1];
	const char *s = essid;
	char *d = escaped;

	if (iwl_is_empty_essid(essid, essid_len)) {
		memcpy(escaped, "<hidden>", sizeof("<hidden>"));
		return escaped;
	}

	essid_len = min(essid_len, (u8) IW_ESSID_MAX_SIZE);
	while (essid_len--) {
		if (*s == '\0') {
			*d++ = '\\';
			*d++ = '0';
			s++;
		} else
			*d++ = *s++;
	}
	*d = '\0';
	return escaped;
}

/**
 * iwl_scan_cancel - Cancel any currently executing HW scan
 *
 * NOTE: priv->mutex is not required before calling this function
 */
int iwl_scan_cancel(struct iwl_priv *priv)
{
	if (!test_bit(STATUS_SCAN_HW, &priv->status)) {
		clear_bit(STATUS_SCANNING, &priv->status);
		return 0;
	}

	if (test_bit(STATUS_SCANNING, &priv->status)) {
		if (!test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
			IWL_DEBUG_SCAN("Queuing scan abort.\n");
			set_bit(STATUS_SCAN_ABORTING, &priv->status);
			queue_work(priv->workqueue, &priv->abort_scan);

		} else
			IWL_DEBUG_SCAN("Scan abort already in progress.\n");

		return test_bit(STATUS_SCANNING, &priv->status);
	}

	return 0;
}
EXPORT_SYMBOL(iwl_scan_cancel);
/**
 * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
 * @ms: amount of time to wait (in milliseconds) for scan to abort
 *
 * NOTE: priv->mutex must be held before calling this function
 */
int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
{
	unsigned long now = jiffies;
	int ret;

	ret = iwl_scan_cancel(priv);
	if (ret && ms) {
		mutex_unlock(&priv->mutex);
		while (!time_after(jiffies, now + msecs_to_jiffies(ms)) &&
				test_bit(STATUS_SCANNING, &priv->status))
			msleep(1);
		mutex_lock(&priv->mutex);

		return test_bit(STATUS_SCANNING, &priv->status);
	}

	return ret;
}
EXPORT_SYMBOL(iwl_scan_cancel_timeout);

static int iwl_send_scan_abort(struct iwl_priv *priv)
{
	int ret = 0;
	struct iwl_rx_packet *res;
	struct iwl_host_cmd cmd = {
		.id = REPLY_SCAN_ABORT_CMD,
		.meta.flags = CMD_WANT_SKB,
	};

	/* If there isn't a scan actively going on in the hardware
	 * then we are in between scan bands and not actually
	 * actively scanning, so don't send the abort command */
	if (!test_bit(STATUS_SCAN_HW, &priv->status)) {
		clear_bit(STATUS_SCAN_ABORTING, &priv->status);
		return 0;
	}

	ret = iwl_send_cmd_sync(priv, &cmd);
	if (ret) {
		clear_bit(STATUS_SCAN_ABORTING, &priv->status);
		return ret;
	}

	res = (struct iwl_rx_packet *)cmd.meta.u.skb->data;
	if (res->u.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_INFO("SCAN_ABORT returned %d.\n", res->u.status);
		clear_bit(STATUS_SCAN_ABORTING, &priv->status);
		clear_bit(STATUS_SCAN_HW, &priv->status);
	}

	priv->alloc_rxb_skb--;
	dev_kfree_skb_any(cmd.meta.u.skb);

	return ret;
}


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

	IWL_DEBUG_RX("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_mem_buffer *rxb)
{
	struct iwl_rx_packet *pkt = (struct iwl_rx_packet *)rxb->skb->data;
	struct iwl_scanstart_notification *notif =
	    (struct iwl_scanstart_notification *)pkt->u.raw;
	priv->scan_start_tsf = le32_to_cpu(notif->tsf_low);
	IWL_DEBUG_SCAN("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_mem_buffer *rxb)
{
#ifdef CONFIG_IWLWIFI_DEBUG
	struct iwl_rx_packet *pkt = (struct iwl_rx_packet *)rxb->skb->data;
	struct iwl_scanresults_notification *notif =
	    (struct iwl_scanresults_notification *)pkt->u.raw;

	IWL_DEBUG_SCAN("Scan ch.res: "
		       "%d [802.11%s] "
		       "(TSF: 0x%08X:%08X) - %d "
		       "elapsed=%lu usec (%dms since last)\n",
		       notif->channel,
		       notif->band ? "bg" : "a",
		       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,
		       jiffies_to_msecs(elapsed_jiffies
					(priv->last_scan_jiffies, jiffies)));
#endif

	priv->last_scan_jiffies = jiffies;
	priv->next_scan_jiffies = 0;
}

/* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
static void iwl_rx_scan_complete_notif(struct iwl_priv *priv,
				       struct iwl_rx_mem_buffer *rxb)
{
#ifdef CONFIG_IWLWIFI_DEBUG
	struct iwl_rx_packet *pkt = (struct iwl_rx_packet *)rxb->skb->data;
	struct iwl_scancomplete_notification *scan_notif = (void *)pkt->u.raw;

	IWL_DEBUG_SCAN("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);
#endif

	/* The HW is no longer scanning */
	clear_bit(STATUS_SCAN_HW, &priv->status);

	/* The scan completion notification came in, so kill that timer... */
	cancel_delayed_work(&priv->scan_check);

	IWL_DEBUG_INFO("Scan pass on %sGHz took %dms\n",
		       (priv->scan_bands & BIT(IEEE80211_BAND_2GHZ)) ?
						"2.4" : "5.2",
		       jiffies_to_msecs(elapsed_jiffies
					(priv->scan_pass_start, jiffies)));

	/* Remove this scanned band from the list of pending
	 * bands to scan, band G precedes A in order of scanning
	 * as seen in iwl_bg_request_scan */
	if (priv->scan_bands & BIT(IEEE80211_BAND_2GHZ))
		priv->scan_bands &= ~BIT(IEEE80211_BAND_2GHZ);
	else if (priv->scan_bands &  BIT(IEEE80211_BAND_5GHZ))
		priv->scan_bands &= ~BIT(IEEE80211_BAND_5GHZ);

	/* If a request to abort was given, or the scan did not succeed
	 * then we reset the scan state machine and terminate,
	 * re-queuing another scan if one has been requested */
	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
		IWL_DEBUG_INFO("Aborted scan completed.\n");
		clear_bit(STATUS_SCAN_ABORTING, &priv->status);
	} else {
		/* If there are more bands on this scan pass reschedule */
		if (priv->scan_bands)
			goto reschedule;
	}

	priv->last_scan_jiffies = jiffies;
	priv->next_scan_jiffies = 0;
	IWL_DEBUG_INFO("Setting scan to off\n");

	clear_bit(STATUS_SCANNING, &priv->status);

	IWL_DEBUG_INFO("Scan took %dms\n",
		jiffies_to_msecs(elapsed_jiffies(priv->scan_start, jiffies)));

	queue_work(priv->workqueue, &priv->scan_completed);

	return;

reschedule:
	priv->scan_pass_start = jiffies;
	queue_work(priv->workqueue, &priv->request_scan);
}

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;
}
EXPORT_SYMBOL(iwl_setup_rx_scan_handlers);

static inline u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
					    enum ieee80211_band band,
					    u8 n_probes)
{
	if (band == IEEE80211_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_get_passive_dwell_time(struct iwl_priv *priv,
				      enum ieee80211_band band)
{
	u16 passive = (band == IEEE80211_BAND_2GHZ) ?
	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;

	if (iwl_is_associated(priv)) {
		/* If we're associated, we clamp the maximum passive
		 * dwell time to be 98% of the beacon interval (minus
		 * 2 * channel tune time) */
		passive = priv->beacon_int;
		if ((passive > IWL_PASSIVE_DWELL_BASE) || !passive)
			passive = IWL_PASSIVE_DWELL_BASE;
		passive = (passive * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
	}

	return passive;
}

static int iwl_get_channels_for_scan(struct iwl_priv *priv,
				     enum ieee80211_band band,
				     u8 is_active, u8 n_probes,
				     struct iwl_scan_channel *scan_ch)
{
	const struct ieee80211_channel *channels = NULL;
	const struct ieee80211_supported_band *sband;
	const struct iwl_channel_info *ch_info;
	u16 passive_dwell = 0;
	u16 active_dwell = 0;
	int added, i;
	u16 channel;

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

	channels = sband->channels;

	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 < sband->n_channels; i++) {
		if (channels[i].flags & IEEE80211_CHAN_DISABLED)
			continue;

		channel =
			ieee80211_frequency_to_channel(channels[i].center_freq);
		scan_ch->channel = cpu_to_le16(channel);

		ch_info = iwl_get_channel_info(priv, band, channel);
		if (!is_channel_valid(ch_info)) {
			IWL_DEBUG_SCAN("Channel %d is INVALID for this band.\n",
					channel);
			continue;
		}

		if (!is_active || is_channel_passive(ch_info) ||
		    (channels[i].flags & IEEE80211_CHAN_PASSIVE_SCAN))
			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 == IEEE80211_BAND_5GHZ)
			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
		else
			scan_ch->tx_gain = ((1 << 5) | (5 << 3));

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

void iwl_init_scan_params(struct iwl_priv *priv)
{
	if (!priv->scan_tx_ant[IEEE80211_BAND_5GHZ])
		priv->scan_tx_ant[IEEE80211_BAND_5GHZ] = RATE_MCS_ANT_INIT_IND;
	if (!priv->scan_tx_ant[IEEE80211_BAND_2GHZ])
		priv->scan_tx_ant[IEEE80211_BAND_2GHZ] = RATE_MCS_ANT_INIT_IND;
}

int iwl_scan_initiate(struct iwl_priv *priv)
{
	if (!iwl_is_ready_rf(priv)) {
		IWL_DEBUG_SCAN("Aborting scan due to not ready.\n");
		return -EIO;
	}

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

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

	IWL_DEBUG_INFO("Starting scan...\n");
	if (priv->cfg->sku & IWL_SKU_G)
		priv->scan_bands |= BIT(IEEE80211_BAND_2GHZ);
	if (priv->cfg->sku & IWL_SKU_A)
		priv->scan_bands |= BIT(IEEE80211_BAND_5GHZ);
	set_bit(STATUS_SCANNING, &priv->status);
	priv->scan_start = jiffies;
	priv->scan_pass_start = priv->scan_start;

	queue_work(priv->workqueue, &priv->request_scan);

	return 0;
}
EXPORT_SYMBOL(iwl_scan_initiate);

#define IWL_SCAN_CHECK_WATCHDOG (7 * HZ)

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

	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
		return;

	mutex_lock(&priv->mutex);
	if (test_bit(STATUS_SCANNING, &priv->status) ||
	    test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
		IWL_DEBUG(IWL_DL_SCAN, "Scan completion watchdog resetting "
			"adapter (%dms)\n",
			jiffies_to_msecs(IWL_SCAN_CHECK_WATCHDOG));

		if (!test_bit(STATUS_EXIT_PENDING, &priv->status))
			iwl_send_scan_abort(priv);
	}
	mutex_unlock(&priv->mutex);
}
/**
 * iwl_supported_rate_to_ie - fill in the supported rate in IE field
 *
 * return : set the bit for each supported rate insert in ie
 */
static u16 iwl_supported_rate_to_ie(u8 *ie, u16 supported_rate,
				    u16 basic_rate, int *left)
{
	u16 ret_rates = 0, bit;
	int i;
	u8 *cnt = ie;
	u8 *rates = ie + 1;

	for (bit = 1, i = 0; i < IWL_RATE_COUNT; i++, bit <<= 1) {
		if (bit & supported_rate) {
			ret_rates |= bit;
			rates[*cnt] = iwl_rates[i].ieee |
				((bit & basic_rate) ? 0x80 : 0x00);
			(*cnt)++;
			(*left)--;
			if ((*left <= 0) ||
			    (*cnt >= IWL_SUPPORTED_RATES_IE_LEN))
				break;
		}
	}

	return ret_rates;
}


static void iwl_ht_cap_to_ie(const struct ieee80211_supported_band *sband,
			     u8 *pos, int *left)
{
	struct ieee80211_ht_cap *ht_cap;

	if (!sband || !sband->ht_info.ht_supported)
		return;

	if (*left < sizeof(struct ieee80211_ht_cap))
		return;

	*pos++ = sizeof(struct ieee80211_ht_cap);
	ht_cap = (struct ieee80211_ht_cap *) pos;

	ht_cap->cap_info = cpu_to_le16(sband->ht_info.cap);
	memcpy(ht_cap->supp_mcs_set, sband->ht_info.supp_mcs_set, 16);
	ht_cap->ampdu_params_info =
		(sband->ht_info.ampdu_factor & IEEE80211_HT_CAP_AMPDU_FACTOR) |
		((sband->ht_info.ampdu_density << 2) &
			IEEE80211_HT_CAP_AMPDU_DENSITY);
	*left -= sizeof(struct ieee80211_ht_cap);
}

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

static u16 iwl_fill_probe_req(struct iwl_priv *priv,
				  enum ieee80211_band band,
				  struct ieee80211_mgmt *frame,
				  int left)
{
	int len = 0;
	u8 *pos = NULL;
	u16 active_rates, ret_rates, cck_rates, active_rate_basic;
	const struct ieee80211_supported_band *sband =
						iwl_get_hw_mode(priv, band);


	/* 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);
	memcpy(frame->da, iwl_bcast_addr, ETH_ALEN);
	memcpy(frame->sa, priv->mac_addr, ETH_ALEN);
	memcpy(frame->bssid, iwl_bcast_addr, ETH_ALEN);
	frame->seq_ctrl = 0;

	len += 24;

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

	/* fill in our indirect SSID IE */
	left -= 2;
	if (left < 0)
		return 0;
	*pos++ = WLAN_EID_SSID;
	*pos++ = 0;

	len += 2;

	/* fill in supported rate */
	left -= 2;
	if (left < 0)
		return 0;

	*pos++ = WLAN_EID_SUPP_RATES;
	*pos = 0;

	/* exclude 60M rate */
	active_rates = priv->rates_mask;
	active_rates &= ~IWL_RATE_60M_MASK;

	active_rate_basic = active_rates & IWL_BASIC_RATES_MASK;

	cck_rates = IWL_CCK_RATES_MASK & active_rates;
	ret_rates = iwl_supported_rate_to_ie(pos, cck_rates,
					     active_rate_basic, &left);
	active_rates &= ~ret_rates;

	ret_rates = iwl_supported_rate_to_ie(pos, active_rates,
					     active_rate_basic, &left);
	active_rates &= ~ret_rates;

	len += 2 + *pos;
	pos += (*pos) + 1;

	if (active_rates == 0)
		goto fill_end;

	/* fill in supported extended rate */
	/* ...next IE... */
	left -= 2;
	if (left < 0)
		return 0;
	/* ... fill it in... */
	*pos++ = WLAN_EID_EXT_SUPP_RATES;
	*pos = 0;
	iwl_supported_rate_to_ie(pos, active_rates, active_rate_basic, &left);
	if (*pos > 0) {
		len += 2 + *pos;
		pos += (*pos) + 1;
	} else {
		pos--;
	}

 fill_end:

	left -= 2;
	if (left < 0)
		return 0;

	*pos++ = WLAN_EID_HT_CAPABILITY;
	*pos = 0;
	iwl_ht_cap_to_ie(sband, pos, &left);
	if (*pos > 0)
		len += 2 + *pos;

	return (u16)len;
}

static u32 iwl_scan_tx_ant(struct iwl_priv *priv, enum ieee80211_band band)
{
	int i, ind;

	ind = priv->scan_tx_ant[band];
	for (i = 0; i < priv->hw_params.tx_chains_num; i++) {
		ind = (ind+1) >= priv->hw_params.tx_chains_num ? 0 : ind+1;
		if (priv->hw_params.valid_tx_ant & (1 << ind)) {
			priv->scan_tx_ant[band] = ind;
			break;
		}
	}
	IWL_DEBUG_SCAN("select TX ANT = %c\n", 'A' + ind);
	return scan_tx_ant[ind];
}


static void iwl_bg_request_scan(struct work_struct *data)
{
	struct iwl_priv *priv =
	    container_of(data, struct iwl_priv, request_scan);
	struct iwl_host_cmd cmd = {
		.id = REPLY_SCAN_CMD,
		.len = sizeof(struct iwl_scan_cmd),
		.meta.flags = CMD_SIZE_HUGE,
	};
	struct iwl_scan_cmd *scan;
	struct ieee80211_conf *conf = NULL;
	int ret = 0;
	u32 tx_ant;
	u16 cmd_len;
	enum ieee80211_band band;
	u8 n_probes = 2;
	u8 rx_chain = priv->hw_params.valid_rx_ant;

	conf = ieee80211_get_hw_conf(priv->hw);

	mutex_lock(&priv->mutex);

	if (!iwl_is_ready(priv)) {
		IWL_WARNING("request scan called when driver not ready.\n");
		goto done;
	}

	/* Make sure the scan wasn't cancelled before this queued work
	 * was given the chance to run... */
	if (!test_bit(STATUS_SCANNING, &priv->status))
		goto done;

	/* This should never be called or scheduled if there is currently
	 * a scan active in the hardware. */
	if (test_bit(STATUS_SCAN_HW, &priv->status)) {
		IWL_DEBUG_INFO("Multiple concurrent scan requests in parallel. "
			       "Ignoring second request.\n");
		ret = -EIO;
		goto done;
	}

	if (test_bit(STATUS_EXIT_PENDING, &priv->status)) {
		IWL_DEBUG_SCAN("Aborting scan due to device shutdown\n");
		goto done;
	}

	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
		IWL_DEBUG_HC("Scan request while abort pending.  Queuing.\n");
		goto done;
	}

	if (iwl_is_rfkill(priv)) {
		IWL_DEBUG_HC("Aborting scan due to RF Kill activation\n");
		goto done;
	}

	if (!test_bit(STATUS_READY, &priv->status)) {
		IWL_DEBUG_HC("Scan request while uninitialized.  Queuing.\n");
		goto done;
	}

	if (!priv->scan_bands) {
		IWL_DEBUG_HC("Aborting scan due to no requested bands\n");
		goto done;
	}

	if (!priv->scan) {
		priv->scan = kmalloc(sizeof(struct iwl_scan_cmd) +
				     IWL_MAX_SCAN_SIZE, GFP_KERNEL);
		if (!priv->scan) {
			ret = -ENOMEM;
			goto done;
		}
	}
	scan = priv->scan;
	memset(scan, 0, sizeof(struct iwl_scan_cmd) + IWL_MAX_SCAN_SIZE);

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

	if (iwl_is_associated(priv)) {
		u16 interval = 0;
		u32 extra;
		u32 suspend_time = 100;
		u32 scan_suspend_time = 100;
		unsigned long flags;

		IWL_DEBUG_INFO("Scanning while associated...\n");

		spin_lock_irqsave(&priv->lock, flags);
		interval = priv->beacon_int;
		spin_unlock_irqrestore(&priv->lock, flags);

		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("suspend_time 0x%X beacon interval %d\n",
			       scan_suspend_time, interval);
	}

	/* We should add the ability for user to lock to PASSIVE ONLY */
	if (priv->one_direct_scan) {
		IWL_DEBUG_SCAN("Start direct scan for '%s'\n",
				iwl_escape_essid(priv->direct_ssid,
				priv->direct_ssid_len));
		scan->direct_scan[0].id = WLAN_EID_SSID;
		scan->direct_scan[0].len = priv->direct_ssid_len;
		memcpy(scan->direct_scan[0].ssid,
		       priv->direct_ssid, priv->direct_ssid_len);
		n_probes++;
	} else if (!iwl_is_associated(priv) && priv->essid_len) {
		IWL_DEBUG_SCAN("Start direct scan for '%s' (not associated)\n",
				iwl_escape_essid(priv->essid, priv->essid_len));
		scan->direct_scan[0].id = WLAN_EID_SSID;
		scan->direct_scan[0].len = priv->essid_len;
		memcpy(scan->direct_scan[0].ssid, priv->essid, priv->essid_len);
		n_probes++;
	} else {
		IWL_DEBUG_SCAN("Start indirect scan.\n");
	}

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


	if (priv->scan_bands & BIT(IEEE80211_BAND_2GHZ)) {
		band = IEEE80211_BAND_2GHZ;
		scan->flags = RXON_FLG_BAND_24G_MSK | RXON_FLG_AUTO_DETECT_MSK;
		tx_ant = iwl_scan_tx_ant(priv, band);
		if (priv->active_rxon.flags & RXON_FLG_CHANNEL_MODE_PURE_40_MSK)
			scan->tx_cmd.rate_n_flags =
				iwl_hw_set_rate_n_flags(IWL_RATE_6M_PLCP,
							tx_ant);
		else
			scan->tx_cmd.rate_n_flags =
				iwl_hw_set_rate_n_flags(IWL_RATE_1M_PLCP,
							tx_ant |
							RATE_MCS_CCK_MSK);
		scan->good_CRC_th = 0;
	} else if (priv->scan_bands & BIT(IEEE80211_BAND_5GHZ)) {
		band = IEEE80211_BAND_5GHZ;
		tx_ant = iwl_scan_tx_ant(priv, band);
		scan->tx_cmd.rate_n_flags =
				iwl_hw_set_rate_n_flags(IWL_RATE_6M_PLCP,
							tx_ant);
		scan->good_CRC_th = IWL_GOOD_CRC_TH;

		/* Force use of chains B and C (0x6) for scan Rx for 4965
		 * Avoid A (0x1) because of its off-channel reception on A-band.
		 */
		if ((priv->hw_rev & CSR_HW_REV_TYPE_MSK) == CSR_HW_REV_TYPE_4965)
			rx_chain = 0x6;
	} else {
		IWL_WARNING("Invalid scan band count\n");
		goto done;
	}

	/* MIMO is not used here, but value is required */
	scan->rx_chain = RXON_RX_CHAIN_DRIVER_FORCE_MSK |
				cpu_to_le16((0x7 << RXON_RX_CHAIN_VALID_POS) |
				(rx_chain << RXON_RX_CHAIN_FORCE_SEL_POS) |
				(0x7 << RXON_RX_CHAIN_FORCE_MIMO_SEL_POS));

	cmd_len = iwl_fill_probe_req(priv, band,
				     (struct ieee80211_mgmt *)scan->data,
				     IWL_MAX_SCAN_SIZE - sizeof(*scan));

	scan->tx_cmd.len = cpu_to_le16(cmd_len);

	if (priv->iw_mode == NL80211_IFTYPE_MONITOR)
		scan->filter_flags = RXON_FILTER_PROMISC_MSK;

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

	scan->channel_count =
		iwl_get_channels_for_scan(priv, band, 1, /* active */
			n_probes,
			(void *)&scan->data[le16_to_cpu(scan->tx_cmd.len)]);

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

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

	set_bit(STATUS_SCAN_HW, &priv->status);
	ret = iwl_send_cmd_sync(priv, &cmd);
	if (ret)
		goto done;

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

	mutex_unlock(&priv->mutex);
	return;

 done:
	/* Cannot perform scan. Make sure we clear scanning
	* bits from status so next scan request can be performed.
	* If we don't clear scanning status bit here all next scan
	* will fail
	*/
	clear_bit(STATUS_SCAN_HW, &priv->status);
	clear_bit(STATUS_SCANNING, &priv->status);
	/* inform mac80211 scan aborted */
	queue_work(priv->workqueue, &priv->scan_completed);
	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);

	if (!iwl_is_ready(priv))
		return;

	mutex_lock(&priv->mutex);

	set_bit(STATUS_SCAN_ABORTING, &priv->status);
	iwl_send_scan_abort(priv);

	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);

	IWL_DEBUG_SCAN("SCAN complete scan\n");

	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
		return;

	ieee80211_scan_completed(priv->hw);

	/* Since setting the TXPOWER may have been deferred while
	 * performing the scan, fire one off */
	mutex_lock(&priv->mutex);
	iwl_set_tx_power(priv, priv->tx_power_user_lmt, true);
	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->request_scan, iwl_bg_request_scan);
	INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
	INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
}
EXPORT_SYMBOL(iwl_setup_scan_deferred_work);