1 /******************************************************************************
2  *
3  * GPL LICENSE SUMMARY
4  *
5  * Copyright(c) 2008 - 2014 Intel Corporation. All rights reserved.
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of version 2 of the GNU General Public License as
9  * published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful, but
12  * WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * The full GNU General Public License is included in this distribution
17  * in the file called COPYING.
18  *
19  * Contact Information:
20  *  Intel Linux Wireless <linuxwifi@intel.com>
21  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
22  *****************************************************************************/
23 #include <linux/slab.h>
24 #include <linux/types.h>
25 #include <linux/etherdevice.h>
26 #include <net/mac80211.h>
27 
28 #include "dev.h"
29 #include "agn.h"
30 
31 /* For active scan, listen ACTIVE_DWELL_TIME (msec) on each channel after
32  * sending probe req.  This should be set long enough to hear probe responses
33  * from more than one AP.  */
34 #define IWL_ACTIVE_DWELL_TIME_24    (30)       /* all times in msec */
35 #define IWL_ACTIVE_DWELL_TIME_52    (20)
36 
37 #define IWL_ACTIVE_DWELL_FACTOR_24GHZ (3)
38 #define IWL_ACTIVE_DWELL_FACTOR_52GHZ (2)
39 
40 /* For passive scan, listen PASSIVE_DWELL_TIME (msec) on each channel.
41  * Must be set longer than active dwell time.
42  * For the most reliable scan, set > AP beacon interval (typically 100msec). */
43 #define IWL_PASSIVE_DWELL_TIME_24   (20)       /* all times in msec */
44 #define IWL_PASSIVE_DWELL_TIME_52   (10)
45 #define IWL_PASSIVE_DWELL_BASE      (100)
46 #define IWL_CHANNEL_TUNE_TIME       5
47 #define MAX_SCAN_CHANNEL	    50
48 
49 /* For reset radio, need minimal dwell time only */
50 #define IWL_RADIO_RESET_DWELL_TIME	5
51 
52 static int iwl_send_scan_abort(struct iwl_priv *priv)
53 {
54 	int ret;
55 	struct iwl_host_cmd cmd = {
56 		.id = REPLY_SCAN_ABORT_CMD,
57 		.flags = CMD_WANT_SKB,
58 	};
59 	__le32 *status;
60 
61 	/* Exit instantly with error when device is not ready
62 	 * to receive scan abort command or it does not perform
63 	 * hardware scan currently */
64 	if (!test_bit(STATUS_READY, &priv->status) ||
65 	    !test_bit(STATUS_SCAN_HW, &priv->status) ||
66 	    test_bit(STATUS_FW_ERROR, &priv->status))
67 		return -EIO;
68 
69 	ret = iwl_dvm_send_cmd(priv, &cmd);
70 	if (ret)
71 		return ret;
72 
73 	status = (void *)cmd.resp_pkt->data;
74 	if (*status != CAN_ABORT_STATUS) {
75 		/* The scan abort will return 1 for success or
76 		 * 2 for "failure".  A failure condition can be
77 		 * due to simply not being in an active scan which
78 		 * can occur if we send the scan abort before we
79 		 * the microcode has notified us that a scan is
80 		 * completed. */
81 		IWL_DEBUG_SCAN(priv, "SCAN_ABORT ret %d.\n",
82 			       le32_to_cpu(*status));
83 		ret = -EIO;
84 	}
85 
86 	iwl_free_resp(&cmd);
87 	return ret;
88 }
89 
90 static void iwl_complete_scan(struct iwl_priv *priv, bool aborted)
91 {
92 	struct cfg80211_scan_info info = {
93 		.aborted = aborted,
94 	};
95 
96 	/* check if scan was requested from mac80211 */
97 	if (priv->scan_request) {
98 		IWL_DEBUG_SCAN(priv, "Complete scan in mac80211\n");
99 		ieee80211_scan_completed(priv->hw, &info);
100 	}
101 
102 	priv->scan_type = IWL_SCAN_NORMAL;
103 	priv->scan_vif = NULL;
104 	priv->scan_request = NULL;
105 }
106 
107 static void iwl_process_scan_complete(struct iwl_priv *priv)
108 {
109 	bool aborted;
110 
111 	lockdep_assert_held(&priv->mutex);
112 
113 	if (!test_and_clear_bit(STATUS_SCAN_COMPLETE, &priv->status))
114 		return;
115 
116 	IWL_DEBUG_SCAN(priv, "Completed scan.\n");
117 
118 	cancel_delayed_work(&priv->scan_check);
119 
120 	aborted = test_and_clear_bit(STATUS_SCAN_ABORTING, &priv->status);
121 	if (aborted)
122 		IWL_DEBUG_SCAN(priv, "Aborted scan completed.\n");
123 
124 	if (!test_and_clear_bit(STATUS_SCANNING, &priv->status)) {
125 		IWL_DEBUG_SCAN(priv, "Scan already completed.\n");
126 		goto out_settings;
127 	}
128 
129 	if (priv->scan_type != IWL_SCAN_NORMAL && !aborted) {
130 		int err;
131 
132 		/* Check if mac80211 requested scan during our internal scan */
133 		if (priv->scan_request == NULL)
134 			goto out_complete;
135 
136 		/* If so request a new scan */
137 		err = iwl_scan_initiate(priv, priv->scan_vif, IWL_SCAN_NORMAL,
138 					priv->scan_request->channels[0]->band);
139 		if (err) {
140 			IWL_DEBUG_SCAN(priv,
141 				"failed to initiate pending scan: %d\n", err);
142 			aborted = true;
143 			goto out_complete;
144 		}
145 
146 		return;
147 	}
148 
149 out_complete:
150 	iwl_complete_scan(priv, aborted);
151 
152 out_settings:
153 	/* Can we still talk to firmware ? */
154 	if (!iwl_is_ready_rf(priv))
155 		return;
156 
157 	iwlagn_post_scan(priv);
158 }
159 
160 void iwl_force_scan_end(struct iwl_priv *priv)
161 {
162 	lockdep_assert_held(&priv->mutex);
163 
164 	if (!test_bit(STATUS_SCANNING, &priv->status)) {
165 		IWL_DEBUG_SCAN(priv, "Forcing scan end while not scanning\n");
166 		return;
167 	}
168 
169 	IWL_DEBUG_SCAN(priv, "Forcing scan end\n");
170 	clear_bit(STATUS_SCANNING, &priv->status);
171 	clear_bit(STATUS_SCAN_HW, &priv->status);
172 	clear_bit(STATUS_SCAN_ABORTING, &priv->status);
173 	clear_bit(STATUS_SCAN_COMPLETE, &priv->status);
174 	iwl_complete_scan(priv, true);
175 }
176 
177 static void iwl_do_scan_abort(struct iwl_priv *priv)
178 {
179 	int ret;
180 
181 	lockdep_assert_held(&priv->mutex);
182 
183 	if (!test_bit(STATUS_SCANNING, &priv->status)) {
184 		IWL_DEBUG_SCAN(priv, "Not performing scan to abort\n");
185 		return;
186 	}
187 
188 	if (test_and_set_bit(STATUS_SCAN_ABORTING, &priv->status)) {
189 		IWL_DEBUG_SCAN(priv, "Scan abort in progress\n");
190 		return;
191 	}
192 
193 	ret = iwl_send_scan_abort(priv);
194 	if (ret) {
195 		IWL_DEBUG_SCAN(priv, "Send scan abort failed %d\n", ret);
196 		iwl_force_scan_end(priv);
197 	} else
198 		IWL_DEBUG_SCAN(priv, "Successfully send scan abort\n");
199 }
200 
201 /**
202  * iwl_scan_cancel - Cancel any currently executing HW scan
203  */
204 int iwl_scan_cancel(struct iwl_priv *priv)
205 {
206 	IWL_DEBUG_SCAN(priv, "Queuing abort scan\n");
207 	queue_work(priv->workqueue, &priv->abort_scan);
208 	return 0;
209 }
210 
211 /**
212  * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
213  * @ms: amount of time to wait (in milliseconds) for scan to abort
214  *
215  */
216 void iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
217 {
218 	unsigned long timeout = jiffies + msecs_to_jiffies(ms);
219 
220 	lockdep_assert_held(&priv->mutex);
221 
222 	IWL_DEBUG_SCAN(priv, "Scan cancel timeout\n");
223 
224 	iwl_do_scan_abort(priv);
225 
226 	while (time_before_eq(jiffies, timeout)) {
227 		if (!test_bit(STATUS_SCAN_HW, &priv->status))
228 			goto finished;
229 		msleep(20);
230 	}
231 
232 	return;
233 
234  finished:
235 	/*
236 	 * Now STATUS_SCAN_HW is clear. This means that the
237 	 * device finished, but the background work is going
238 	 * to execute at best as soon as we release the mutex.
239 	 * Since we need to be able to issue a new scan right
240 	 * after this function returns, run the complete here.
241 	 * The STATUS_SCAN_COMPLETE bit will then be cleared
242 	 * and prevent the background work from "completing"
243 	 * a possible new scan.
244 	 */
245 	iwl_process_scan_complete(priv);
246 }
247 
248 /* Service response to REPLY_SCAN_CMD (0x80) */
249 static void iwl_rx_reply_scan(struct iwl_priv *priv,
250 			      struct iwl_rx_cmd_buffer *rxb)
251 {
252 #ifdef CONFIG_IWLWIFI_DEBUG
253 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
254 	struct iwl_scanreq_notification *notif = (void *)pkt->data;
255 
256 	IWL_DEBUG_SCAN(priv, "Scan request status = 0x%x\n", notif->status);
257 #endif
258 }
259 
260 /* Service SCAN_START_NOTIFICATION (0x82) */
261 static void iwl_rx_scan_start_notif(struct iwl_priv *priv,
262 				    struct iwl_rx_cmd_buffer *rxb)
263 {
264 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
265 	struct iwl_scanstart_notification *notif = (void *)pkt->data;
266 
267 	priv->scan_start_tsf = le32_to_cpu(notif->tsf_low);
268 	IWL_DEBUG_SCAN(priv, "Scan start: "
269 		       "%d [802.11%s] "
270 		       "(TSF: 0x%08X:%08X) - %d (beacon timer %u)\n",
271 		       notif->channel,
272 		       notif->band ? "bg" : "a",
273 		       le32_to_cpu(notif->tsf_high),
274 		       le32_to_cpu(notif->tsf_low),
275 		       notif->status, notif->beacon_timer);
276 }
277 
278 /* Service SCAN_RESULTS_NOTIFICATION (0x83) */
279 static void iwl_rx_scan_results_notif(struct iwl_priv *priv,
280 				      struct iwl_rx_cmd_buffer *rxb)
281 {
282 #ifdef CONFIG_IWLWIFI_DEBUG
283 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
284 	struct iwl_scanresults_notification *notif = (void *)pkt->data;
285 
286 	IWL_DEBUG_SCAN(priv, "Scan ch.res: "
287 		       "%d [802.11%s] "
288 		       "probe status: %u:%u "
289 		       "(TSF: 0x%08X:%08X) - %d "
290 		       "elapsed=%lu usec\n",
291 		       notif->channel,
292 		       notif->band ? "bg" : "a",
293 		       notif->probe_status, notif->num_probe_not_sent,
294 		       le32_to_cpu(notif->tsf_high),
295 		       le32_to_cpu(notif->tsf_low),
296 		       le32_to_cpu(notif->statistics[0]),
297 		       le32_to_cpu(notif->tsf_low) - priv->scan_start_tsf);
298 #endif
299 }
300 
301 /* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
302 static void iwl_rx_scan_complete_notif(struct iwl_priv *priv,
303 				       struct iwl_rx_cmd_buffer *rxb)
304 {
305 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
306 	struct iwl_scancomplete_notification *scan_notif = (void *)pkt->data;
307 
308 	IWL_DEBUG_SCAN(priv, "Scan complete: %d channels (TSF 0x%08X:%08X) - %d\n",
309 		       scan_notif->scanned_channels,
310 		       scan_notif->tsf_low,
311 		       scan_notif->tsf_high, scan_notif->status);
312 
313 	IWL_DEBUG_SCAN(priv, "Scan on %sGHz took %dms\n",
314 		       (priv->scan_band == NL80211_BAND_2GHZ) ? "2.4" : "5.2",
315 		       jiffies_to_msecs(jiffies - priv->scan_start));
316 
317 	/*
318 	 * When aborting, we run the scan completed background work inline
319 	 * and the background work must then do nothing. The SCAN_COMPLETE
320 	 * bit helps implement that logic and thus needs to be set before
321 	 * queueing the work. Also, since the scan abort waits for SCAN_HW
322 	 * to clear, we need to set SCAN_COMPLETE before clearing SCAN_HW
323 	 * to avoid a race there.
324 	 */
325 	set_bit(STATUS_SCAN_COMPLETE, &priv->status);
326 	clear_bit(STATUS_SCAN_HW, &priv->status);
327 	queue_work(priv->workqueue, &priv->scan_completed);
328 
329 	if (priv->iw_mode != NL80211_IFTYPE_ADHOC &&
330 	    iwl_advanced_bt_coexist(priv) &&
331 	    priv->bt_status != scan_notif->bt_status) {
332 		if (scan_notif->bt_status) {
333 			/* BT on */
334 			if (!priv->bt_ch_announce)
335 				priv->bt_traffic_load =
336 					IWL_BT_COEX_TRAFFIC_LOAD_HIGH;
337 			/*
338 			 * otherwise, no traffic load information provided
339 			 * no changes made
340 			 */
341 		} else {
342 			/* BT off */
343 			priv->bt_traffic_load =
344 				IWL_BT_COEX_TRAFFIC_LOAD_NONE;
345 		}
346 		priv->bt_status = scan_notif->bt_status;
347 		queue_work(priv->workqueue,
348 			   &priv->bt_traffic_change_work);
349 	}
350 }
351 
352 void iwl_setup_rx_scan_handlers(struct iwl_priv *priv)
353 {
354 	/* scan handlers */
355 	priv->rx_handlers[REPLY_SCAN_CMD] = iwl_rx_reply_scan;
356 	priv->rx_handlers[SCAN_START_NOTIFICATION] = iwl_rx_scan_start_notif;
357 	priv->rx_handlers[SCAN_RESULTS_NOTIFICATION] =
358 					iwl_rx_scan_results_notif;
359 	priv->rx_handlers[SCAN_COMPLETE_NOTIFICATION] =
360 					iwl_rx_scan_complete_notif;
361 }
362 
363 static u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
364 				     enum nl80211_band band, u8 n_probes)
365 {
366 	if (band == NL80211_BAND_5GHZ)
367 		return IWL_ACTIVE_DWELL_TIME_52 +
368 			IWL_ACTIVE_DWELL_FACTOR_52GHZ * (n_probes + 1);
369 	else
370 		return IWL_ACTIVE_DWELL_TIME_24 +
371 			IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
372 }
373 
374 static u16 iwl_limit_dwell(struct iwl_priv *priv, u16 dwell_time)
375 {
376 	struct iwl_rxon_context *ctx;
377 	int limits[NUM_IWL_RXON_CTX] = {};
378 	int n_active = 0;
379 	u16 limit;
380 
381 	BUILD_BUG_ON(NUM_IWL_RXON_CTX != 2);
382 
383 	/*
384 	 * If we're associated, we clamp the dwell time 98%
385 	 * of the beacon interval (minus 2 * channel tune time)
386 	 * If both contexts are active, we have to restrict to
387 	 * 1/2 of the minimum of them, because they might be in
388 	 * lock-step with the time inbetween only half of what
389 	 * time we'd have in each of them.
390 	 */
391 	for_each_context(priv, ctx) {
392 		switch (ctx->staging.dev_type) {
393 		case RXON_DEV_TYPE_P2P:
394 			/* no timing constraints */
395 			continue;
396 		case RXON_DEV_TYPE_ESS:
397 		default:
398 			/* timing constraints if associated */
399 			if (!iwl_is_associated_ctx(ctx))
400 				continue;
401 			break;
402 		case RXON_DEV_TYPE_CP:
403 		case RXON_DEV_TYPE_2STA:
404 			/*
405 			 * These seem to always have timers for TBTT
406 			 * active in uCode even when not associated yet.
407 			 */
408 			break;
409 		}
410 
411 		limits[n_active++] = ctx->beacon_int ?: IWL_PASSIVE_DWELL_BASE;
412 	}
413 
414 	switch (n_active) {
415 	case 0:
416 		return dwell_time;
417 	case 2:
418 		limit = (limits[1] * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
419 		limit /= 2;
420 		dwell_time = min(limit, dwell_time);
421 		/* fall through to limit further */
422 	case 1:
423 		limit = (limits[0] * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
424 		limit /= n_active;
425 		return min(limit, dwell_time);
426 	default:
427 		WARN_ON_ONCE(1);
428 		return dwell_time;
429 	}
430 }
431 
432 static u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
433 				      enum nl80211_band band)
434 {
435 	u16 passive = (band == NL80211_BAND_2GHZ) ?
436 	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
437 	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;
438 
439 	return iwl_limit_dwell(priv, passive);
440 }
441 
442 /* Return valid, unused, channel for a passive scan to reset the RF */
443 static u8 iwl_get_single_channel_number(struct iwl_priv *priv,
444 					enum nl80211_band band)
445 {
446 	struct ieee80211_supported_band *sband = priv->hw->wiphy->bands[band];
447 	struct iwl_rxon_context *ctx;
448 	int i;
449 
450 	for (i = 0; i < sband->n_channels; i++) {
451 		bool busy = false;
452 
453 		for_each_context(priv, ctx) {
454 			busy = sband->channels[i].hw_value ==
455 				le16_to_cpu(ctx->staging.channel);
456 			if (busy)
457 				break;
458 		}
459 
460 		if (busy)
461 			continue;
462 
463 		if (!(sband->channels[i].flags & IEEE80211_CHAN_DISABLED))
464 			return sband->channels[i].hw_value;
465 	}
466 
467 	return 0;
468 }
469 
470 static int iwl_get_channel_for_reset_scan(struct iwl_priv *priv,
471 					  struct ieee80211_vif *vif,
472 					  enum nl80211_band band,
473 					  struct iwl_scan_channel *scan_ch)
474 {
475 	const struct ieee80211_supported_band *sband;
476 	u16 channel;
477 
478 	sband = iwl_get_hw_mode(priv, band);
479 	if (!sband) {
480 		IWL_ERR(priv, "invalid band\n");
481 		return 0;
482 	}
483 
484 	channel = iwl_get_single_channel_number(priv, band);
485 	if (channel) {
486 		scan_ch->channel = cpu_to_le16(channel);
487 		scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
488 		scan_ch->active_dwell =
489 			cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
490 		scan_ch->passive_dwell =
491 			cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
492 		/* Set txpower levels to defaults */
493 		scan_ch->dsp_atten = 110;
494 		if (band == NL80211_BAND_5GHZ)
495 			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
496 		else
497 			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
498 		return 1;
499 	}
500 
501 	IWL_ERR(priv, "no valid channel found\n");
502 	return 0;
503 }
504 
505 static int iwl_get_channels_for_scan(struct iwl_priv *priv,
506 				     struct ieee80211_vif *vif,
507 				     enum nl80211_band band,
508 				     u8 is_active, u8 n_probes,
509 				     struct iwl_scan_channel *scan_ch)
510 {
511 	struct ieee80211_channel *chan;
512 	const struct ieee80211_supported_band *sband;
513 	u16 passive_dwell = 0;
514 	u16 active_dwell = 0;
515 	int added, i;
516 	u16 channel;
517 
518 	sband = iwl_get_hw_mode(priv, band);
519 	if (!sband)
520 		return 0;
521 
522 	active_dwell = iwl_get_active_dwell_time(priv, band, n_probes);
523 	passive_dwell = iwl_get_passive_dwell_time(priv, band);
524 
525 	if (passive_dwell <= active_dwell)
526 		passive_dwell = active_dwell + 1;
527 
528 	for (i = 0, added = 0; i < priv->scan_request->n_channels; i++) {
529 		chan = priv->scan_request->channels[i];
530 
531 		if (chan->band != band)
532 			continue;
533 
534 		channel = chan->hw_value;
535 		scan_ch->channel = cpu_to_le16(channel);
536 
537 		if (!is_active || (chan->flags & IEEE80211_CHAN_NO_IR))
538 			scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
539 		else
540 			scan_ch->type = SCAN_CHANNEL_TYPE_ACTIVE;
541 
542 		if (n_probes)
543 			scan_ch->type |= IWL_SCAN_PROBE_MASK(n_probes);
544 
545 		scan_ch->active_dwell = cpu_to_le16(active_dwell);
546 		scan_ch->passive_dwell = cpu_to_le16(passive_dwell);
547 
548 		/* Set txpower levels to defaults */
549 		scan_ch->dsp_atten = 110;
550 
551 		/* NOTE: if we were doing 6Mb OFDM for scans we'd use
552 		 * power level:
553 		 * scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
554 		 */
555 		if (band == NL80211_BAND_5GHZ)
556 			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
557 		else
558 			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
559 
560 		IWL_DEBUG_SCAN(priv, "Scanning ch=%d prob=0x%X [%s %d]\n",
561 			       channel, le32_to_cpu(scan_ch->type),
562 			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
563 				"ACTIVE" : "PASSIVE",
564 			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
565 			       active_dwell : passive_dwell);
566 
567 		scan_ch++;
568 		added++;
569 	}
570 
571 	IWL_DEBUG_SCAN(priv, "total channels to scan %d\n", added);
572 	return added;
573 }
574 
575 /**
576  * iwl_fill_probe_req - fill in all required fields and IE for probe request
577  */
578 
579 static u16 iwl_fill_probe_req(struct ieee80211_mgmt *frame, const u8 *ta,
580 			      const u8 *ies, int ie_len, const u8 *ssid,
581 			      u8 ssid_len, int left)
582 {
583 	int len = 0;
584 	u8 *pos = NULL;
585 
586 	/* Make sure there is enough space for the probe request,
587 	 * two mandatory IEs and the data */
588 	left -= 24;
589 	if (left < 0)
590 		return 0;
591 
592 	frame->frame_control = cpu_to_le16(IEEE80211_STYPE_PROBE_REQ);
593 	eth_broadcast_addr(frame->da);
594 	memcpy(frame->sa, ta, ETH_ALEN);
595 	eth_broadcast_addr(frame->bssid);
596 	frame->seq_ctrl = 0;
597 
598 	len += 24;
599 
600 	/* ...next IE... */
601 	pos = &frame->u.probe_req.variable[0];
602 
603 	/* fill in our SSID IE */
604 	left -= ssid_len + 2;
605 	if (left < 0)
606 		return 0;
607 	*pos++ = WLAN_EID_SSID;
608 	*pos++ = ssid_len;
609 	if (ssid && ssid_len) {
610 		memcpy(pos, ssid, ssid_len);
611 		pos += ssid_len;
612 	}
613 
614 	len += ssid_len + 2;
615 
616 	if (WARN_ON(left < ie_len))
617 		return len;
618 
619 	if (ies && ie_len) {
620 		memcpy(pos, ies, ie_len);
621 		len += ie_len;
622 	}
623 
624 	return (u16)len;
625 }
626 
627 static int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
628 {
629 	struct iwl_host_cmd cmd = {
630 		.id = REPLY_SCAN_CMD,
631 		.len = { sizeof(struct iwl_scan_cmd), },
632 	};
633 	struct iwl_scan_cmd *scan;
634 	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
635 	u32 rate_flags = 0;
636 	u16 cmd_len = 0;
637 	u16 rx_chain = 0;
638 	enum nl80211_band band;
639 	u8 n_probes = 0;
640 	u8 rx_ant = priv->nvm_data->valid_rx_ant;
641 	u8 rate;
642 	bool is_active = false;
643 	int  chan_mod;
644 	u8 active_chains;
645 	u8 scan_tx_antennas = priv->nvm_data->valid_tx_ant;
646 	int ret;
647 	int scan_cmd_size = sizeof(struct iwl_scan_cmd) +
648 			    MAX_SCAN_CHANNEL * sizeof(struct iwl_scan_channel) +
649 			    priv->fw->ucode_capa.max_probe_length;
650 	const u8 *ssid = NULL;
651 	u8 ssid_len = 0;
652 
653 	if (WARN_ON(priv->scan_type == IWL_SCAN_NORMAL &&
654 		    (!priv->scan_request ||
655 		     priv->scan_request->n_channels > MAX_SCAN_CHANNEL)))
656 		return -EINVAL;
657 
658 	lockdep_assert_held(&priv->mutex);
659 
660 	if (vif)
661 		ctx = iwl_rxon_ctx_from_vif(vif);
662 
663 	if (!priv->scan_cmd) {
664 		priv->scan_cmd = kmalloc(scan_cmd_size, GFP_KERNEL);
665 		if (!priv->scan_cmd) {
666 			IWL_DEBUG_SCAN(priv,
667 				       "fail to allocate memory for scan\n");
668 			return -ENOMEM;
669 		}
670 	}
671 	scan = priv->scan_cmd;
672 	memset(scan, 0, scan_cmd_size);
673 
674 	scan->quiet_plcp_th = IWL_PLCP_QUIET_THRESH;
675 	scan->quiet_time = IWL_ACTIVE_QUIET_TIME;
676 
677 	if (iwl_is_any_associated(priv)) {
678 		u16 interval = 0;
679 		u32 extra;
680 		u32 suspend_time = 100;
681 		u32 scan_suspend_time = 100;
682 
683 		IWL_DEBUG_INFO(priv, "Scanning while associated...\n");
684 		switch (priv->scan_type) {
685 		case IWL_SCAN_RADIO_RESET:
686 			interval = 0;
687 			break;
688 		case IWL_SCAN_NORMAL:
689 			interval = vif->bss_conf.beacon_int;
690 			break;
691 		}
692 
693 		scan->suspend_time = 0;
694 		scan->max_out_time = cpu_to_le32(200 * 1024);
695 		if (!interval)
696 			interval = suspend_time;
697 
698 		extra = (suspend_time / interval) << 22;
699 		scan_suspend_time = (extra |
700 		    ((suspend_time % interval) * 1024));
701 		scan->suspend_time = cpu_to_le32(scan_suspend_time);
702 		IWL_DEBUG_SCAN(priv, "suspend_time 0x%X beacon interval %d\n",
703 			       scan_suspend_time, interval);
704 	}
705 
706 	switch (priv->scan_type) {
707 	case IWL_SCAN_RADIO_RESET:
708 		IWL_DEBUG_SCAN(priv, "Start internal passive scan.\n");
709 		/*
710 		 * Override quiet time as firmware checks that active
711 		 * dwell is >= quiet; since we use passive scan it'll
712 		 * not actually be used.
713 		 */
714 		scan->quiet_time = cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
715 		break;
716 	case IWL_SCAN_NORMAL:
717 		if (priv->scan_request->n_ssids) {
718 			int i, p = 0;
719 			IWL_DEBUG_SCAN(priv, "Kicking off active scan\n");
720 			/*
721 			 * The highest priority SSID is inserted to the
722 			 * probe request template.
723 			 */
724 			ssid_len = priv->scan_request->ssids[0].ssid_len;
725 			ssid = priv->scan_request->ssids[0].ssid;
726 
727 			/*
728 			 * Invert the order of ssids, the firmware will invert
729 			 * it back.
730 			 */
731 			for (i = priv->scan_request->n_ssids - 1; i >= 1; i--) {
732 				scan->direct_scan[p].id = WLAN_EID_SSID;
733 				scan->direct_scan[p].len =
734 					priv->scan_request->ssids[i].ssid_len;
735 				memcpy(scan->direct_scan[p].ssid,
736 				       priv->scan_request->ssids[i].ssid,
737 				       priv->scan_request->ssids[i].ssid_len);
738 				n_probes++;
739 				p++;
740 			}
741 			is_active = true;
742 		} else
743 			IWL_DEBUG_SCAN(priv, "Start passive scan.\n");
744 		break;
745 	}
746 
747 	scan->tx_cmd.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK;
748 	scan->tx_cmd.sta_id = ctx->bcast_sta_id;
749 	scan->tx_cmd.stop_time.life_time = TX_CMD_LIFE_TIME_INFINITE;
750 
751 	switch (priv->scan_band) {
752 	case NL80211_BAND_2GHZ:
753 		scan->flags = RXON_FLG_BAND_24G_MSK | RXON_FLG_AUTO_DETECT_MSK;
754 		chan_mod = le32_to_cpu(
755 			priv->contexts[IWL_RXON_CTX_BSS].active.flags &
756 						RXON_FLG_CHANNEL_MODE_MSK)
757 				       >> RXON_FLG_CHANNEL_MODE_POS;
758 		if ((priv->scan_request && priv->scan_request->no_cck) ||
759 		    chan_mod == CHANNEL_MODE_PURE_40) {
760 			rate = IWL_RATE_6M_PLCP;
761 		} else {
762 			rate = IWL_RATE_1M_PLCP;
763 			rate_flags = RATE_MCS_CCK_MSK;
764 		}
765 		/*
766 		 * Internal scans are passive, so we can indiscriminately set
767 		 * the BT ignore flag on 2.4 GHz since it applies to TX only.
768 		 */
769 		if (priv->lib->bt_params &&
770 		    priv->lib->bt_params->advanced_bt_coexist)
771 			scan->tx_cmd.tx_flags |= TX_CMD_FLG_IGNORE_BT;
772 		break;
773 	case NL80211_BAND_5GHZ:
774 		rate = IWL_RATE_6M_PLCP;
775 		break;
776 	default:
777 		IWL_WARN(priv, "Invalid scan band\n");
778 		return -EIO;
779 	}
780 
781 	/*
782 	 * If active scanning is requested but a certain channel is
783 	 * marked passive, we can do active scanning if we detect
784 	 * transmissions.
785 	 *
786 	 * There is an issue with some firmware versions that triggers
787 	 * a sysassert on a "good CRC threshold" of zero (== disabled),
788 	 * on a radar channel even though this means that we should NOT
789 	 * send probes.
790 	 *
791 	 * The "good CRC threshold" is the number of frames that we
792 	 * need to receive during our dwell time on a channel before
793 	 * sending out probes -- setting this to a huge value will
794 	 * mean we never reach it, but at the same time work around
795 	 * the aforementioned issue. Thus use IWL_GOOD_CRC_TH_NEVER
796 	 * here instead of IWL_GOOD_CRC_TH_DISABLED.
797 	 *
798 	 * This was fixed in later versions along with some other
799 	 * scan changes, and the threshold behaves as a flag in those
800 	 * versions.
801 	 */
802 	if (priv->new_scan_threshold_behaviour)
803 		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
804 						IWL_GOOD_CRC_TH_DISABLED;
805 	else
806 		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
807 						IWL_GOOD_CRC_TH_NEVER;
808 
809 	band = priv->scan_band;
810 
811 	if (band == NL80211_BAND_2GHZ &&
812 	    priv->lib->bt_params &&
813 	    priv->lib->bt_params->advanced_bt_coexist) {
814 		/* transmit 2.4 GHz probes only on first antenna */
815 		scan_tx_antennas = first_antenna(scan_tx_antennas);
816 	}
817 
818 	priv->scan_tx_ant[band] = iwl_toggle_tx_ant(priv,
819 						    priv->scan_tx_ant[band],
820 						    scan_tx_antennas);
821 	rate_flags |= iwl_ant_idx_to_flags(priv->scan_tx_ant[band]);
822 	scan->tx_cmd.rate_n_flags = iwl_hw_set_rate_n_flags(rate, rate_flags);
823 
824 	/*
825 	 * In power save mode while associated use one chain,
826 	 * otherwise use all chains
827 	 */
828 	if (test_bit(STATUS_POWER_PMI, &priv->status) &&
829 	    !(priv->hw->conf.flags & IEEE80211_CONF_IDLE)) {
830 		/* rx_ant has been set to all valid chains previously */
831 		active_chains = rx_ant &
832 				((u8)(priv->chain_noise_data.active_chains));
833 		if (!active_chains)
834 			active_chains = rx_ant;
835 
836 		IWL_DEBUG_SCAN(priv, "chain_noise_data.active_chains: %u\n",
837 				priv->chain_noise_data.active_chains);
838 
839 		rx_ant = first_antenna(active_chains);
840 	}
841 	if (priv->lib->bt_params &&
842 	    priv->lib->bt_params->advanced_bt_coexist &&
843 	    priv->bt_full_concurrent) {
844 		/* operated as 1x1 in full concurrency mode */
845 		rx_ant = first_antenna(rx_ant);
846 	}
847 
848 	/* MIMO is not used here, but value is required */
849 	rx_chain |=
850 		priv->nvm_data->valid_rx_ant << RXON_RX_CHAIN_VALID_POS;
851 	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_MIMO_SEL_POS;
852 	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_SEL_POS;
853 	rx_chain |= 0x1 << RXON_RX_CHAIN_DRIVER_FORCE_POS;
854 	scan->rx_chain = cpu_to_le16(rx_chain);
855 	switch (priv->scan_type) {
856 	case IWL_SCAN_NORMAL:
857 		cmd_len = iwl_fill_probe_req(
858 					(struct ieee80211_mgmt *)scan->data,
859 					vif->addr,
860 					priv->scan_request->ie,
861 					priv->scan_request->ie_len,
862 					ssid, ssid_len,
863 					scan_cmd_size - sizeof(*scan));
864 		break;
865 	case IWL_SCAN_RADIO_RESET:
866 		/* use bcast addr, will not be transmitted but must be valid */
867 		cmd_len = iwl_fill_probe_req(
868 					(struct ieee80211_mgmt *)scan->data,
869 					iwl_bcast_addr, NULL, 0,
870 					NULL, 0,
871 					scan_cmd_size - sizeof(*scan));
872 		break;
873 	default:
874 		BUG();
875 	}
876 	scan->tx_cmd.len = cpu_to_le16(cmd_len);
877 
878 	scan->filter_flags |= (RXON_FILTER_ACCEPT_GRP_MSK |
879 			       RXON_FILTER_BCON_AWARE_MSK);
880 
881 	switch (priv->scan_type) {
882 	case IWL_SCAN_RADIO_RESET:
883 		scan->channel_count =
884 			iwl_get_channel_for_reset_scan(priv, vif, band,
885 				(void *)&scan->data[cmd_len]);
886 		break;
887 	case IWL_SCAN_NORMAL:
888 		scan->channel_count =
889 			iwl_get_channels_for_scan(priv, vif, band,
890 				is_active, n_probes,
891 				(void *)&scan->data[cmd_len]);
892 		break;
893 	}
894 
895 	if (scan->channel_count == 0) {
896 		IWL_DEBUG_SCAN(priv, "channel count %d\n", scan->channel_count);
897 		return -EIO;
898 	}
899 
900 	cmd.len[0] += le16_to_cpu(scan->tx_cmd.len) +
901 	    scan->channel_count * sizeof(struct iwl_scan_channel);
902 	cmd.data[0] = scan;
903 	cmd.dataflags[0] = IWL_HCMD_DFL_NOCOPY;
904 	scan->len = cpu_to_le16(cmd.len[0]);
905 
906 	/* set scan bit here for PAN params */
907 	set_bit(STATUS_SCAN_HW, &priv->status);
908 
909 	ret = iwlagn_set_pan_params(priv);
910 	if (ret) {
911 		clear_bit(STATUS_SCAN_HW, &priv->status);
912 		return ret;
913 	}
914 
915 	ret = iwl_dvm_send_cmd(priv, &cmd);
916 	if (ret) {
917 		clear_bit(STATUS_SCAN_HW, &priv->status);
918 		iwlagn_set_pan_params(priv);
919 	}
920 
921 	return ret;
922 }
923 
924 void iwl_init_scan_params(struct iwl_priv *priv)
925 {
926 	u8 ant_idx = fls(priv->nvm_data->valid_tx_ant) - 1;
927 	if (!priv->scan_tx_ant[NL80211_BAND_5GHZ])
928 		priv->scan_tx_ant[NL80211_BAND_5GHZ] = ant_idx;
929 	if (!priv->scan_tx_ant[NL80211_BAND_2GHZ])
930 		priv->scan_tx_ant[NL80211_BAND_2GHZ] = ant_idx;
931 }
932 
933 int __must_check iwl_scan_initiate(struct iwl_priv *priv,
934 				   struct ieee80211_vif *vif,
935 				   enum iwl_scan_type scan_type,
936 				   enum nl80211_band band)
937 {
938 	int ret;
939 
940 	lockdep_assert_held(&priv->mutex);
941 
942 	cancel_delayed_work(&priv->scan_check);
943 
944 	if (!iwl_is_ready_rf(priv)) {
945 		IWL_WARN(priv, "Request scan called when driver not ready.\n");
946 		return -EIO;
947 	}
948 
949 	if (test_bit(STATUS_SCAN_HW, &priv->status)) {
950 		IWL_DEBUG_SCAN(priv,
951 			"Multiple concurrent scan requests in parallel.\n");
952 		return -EBUSY;
953 	}
954 
955 	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
956 		IWL_DEBUG_SCAN(priv, "Scan request while abort pending.\n");
957 		return -EBUSY;
958 	}
959 
960 	IWL_DEBUG_SCAN(priv, "Starting %sscan...\n",
961 			scan_type == IWL_SCAN_NORMAL ? "" :
962 			"internal short ");
963 
964 	set_bit(STATUS_SCANNING, &priv->status);
965 	priv->scan_type = scan_type;
966 	priv->scan_start = jiffies;
967 	priv->scan_band = band;
968 
969 	ret = iwlagn_request_scan(priv, vif);
970 	if (ret) {
971 		clear_bit(STATUS_SCANNING, &priv->status);
972 		priv->scan_type = IWL_SCAN_NORMAL;
973 		return ret;
974 	}
975 
976 	queue_delayed_work(priv->workqueue, &priv->scan_check,
977 			   IWL_SCAN_CHECK_WATCHDOG);
978 
979 	return 0;
980 }
981 
982 
983 /*
984  * internal short scan, this function should only been called while associated.
985  * It will reset and tune the radio to prevent possible RF related problem
986  */
987 void iwl_internal_short_hw_scan(struct iwl_priv *priv)
988 {
989 	queue_work(priv->workqueue, &priv->start_internal_scan);
990 }
991 
992 static void iwl_bg_start_internal_scan(struct work_struct *work)
993 {
994 	struct iwl_priv *priv =
995 		container_of(work, struct iwl_priv, start_internal_scan);
996 
997 	IWL_DEBUG_SCAN(priv, "Start internal scan\n");
998 
999 	mutex_lock(&priv->mutex);
1000 
1001 	if (priv->scan_type == IWL_SCAN_RADIO_RESET) {
1002 		IWL_DEBUG_SCAN(priv, "Internal scan already in progress\n");
1003 		goto unlock;
1004 	}
1005 
1006 	if (test_bit(STATUS_SCANNING, &priv->status)) {
1007 		IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
1008 		goto unlock;
1009 	}
1010 
1011 	if (iwl_scan_initiate(priv, NULL, IWL_SCAN_RADIO_RESET, priv->band))
1012 		IWL_DEBUG_SCAN(priv, "failed to start internal short scan\n");
1013  unlock:
1014 	mutex_unlock(&priv->mutex);
1015 }
1016 
1017 static void iwl_bg_scan_check(struct work_struct *data)
1018 {
1019 	struct iwl_priv *priv =
1020 	    container_of(data, struct iwl_priv, scan_check.work);
1021 
1022 	IWL_DEBUG_SCAN(priv, "Scan check work\n");
1023 
1024 	/* Since we are here firmware does not finish scan and
1025 	 * most likely is in bad shape, so we don't bother to
1026 	 * send abort command, just force scan complete to mac80211 */
1027 	mutex_lock(&priv->mutex);
1028 	iwl_force_scan_end(priv);
1029 	mutex_unlock(&priv->mutex);
1030 }
1031 
1032 static void iwl_bg_abort_scan(struct work_struct *work)
1033 {
1034 	struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);
1035 
1036 	IWL_DEBUG_SCAN(priv, "Abort scan work\n");
1037 
1038 	/* We keep scan_check work queued in case when firmware will not
1039 	 * report back scan completed notification */
1040 	mutex_lock(&priv->mutex);
1041 	iwl_scan_cancel_timeout(priv, 200);
1042 	mutex_unlock(&priv->mutex);
1043 }
1044 
1045 static void iwl_bg_scan_completed(struct work_struct *work)
1046 {
1047 	struct iwl_priv *priv =
1048 		container_of(work, struct iwl_priv, scan_completed);
1049 
1050 	mutex_lock(&priv->mutex);
1051 	iwl_process_scan_complete(priv);
1052 	mutex_unlock(&priv->mutex);
1053 }
1054 
1055 void iwl_setup_scan_deferred_work(struct iwl_priv *priv)
1056 {
1057 	INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed);
1058 	INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
1059 	INIT_WORK(&priv->start_internal_scan, iwl_bg_start_internal_scan);
1060 	INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
1061 }
1062 
1063 void iwl_cancel_scan_deferred_work(struct iwl_priv *priv)
1064 {
1065 	cancel_work_sync(&priv->start_internal_scan);
1066 	cancel_work_sync(&priv->abort_scan);
1067 	cancel_work_sync(&priv->scan_completed);
1068 
1069 	if (cancel_delayed_work_sync(&priv->scan_check)) {
1070 		mutex_lock(&priv->mutex);
1071 		iwl_force_scan_end(priv);
1072 		mutex_unlock(&priv->mutex);
1073 	}
1074 }
1075