1 // SPDX-License-Identifier: GPL-2.0-only
2 /******************************************************************************
3  *
4  * Copyright(c) 2008 - 2014 Intel Corporation. All rights reserved.
5  * Copyright(c) 2018        Intel Corporation
6  *****************************************************************************/
7 #include <linux/slab.h>
8 #include <linux/types.h>
9 #include <linux/etherdevice.h>
10 #include <net/mac80211.h>
11 
12 #include "dev.h"
13 #include "agn.h"
14 
15 /* For active scan, listen ACTIVE_DWELL_TIME (msec) on each channel after
16  * sending probe req.  This should be set long enough to hear probe responses
17  * from more than one AP.  */
18 #define IWL_ACTIVE_DWELL_TIME_24    (30)       /* all times in msec */
19 #define IWL_ACTIVE_DWELL_TIME_52    (20)
20 
21 #define IWL_ACTIVE_DWELL_FACTOR_24GHZ (3)
22 #define IWL_ACTIVE_DWELL_FACTOR_52GHZ (2)
23 
24 /* For passive scan, listen PASSIVE_DWELL_TIME (msec) on each channel.
25  * Must be set longer than active dwell time.
26  * For the most reliable scan, set > AP beacon interval (typically 100msec). */
27 #define IWL_PASSIVE_DWELL_TIME_24   (20)       /* all times in msec */
28 #define IWL_PASSIVE_DWELL_TIME_52   (10)
29 #define IWL_PASSIVE_DWELL_BASE      (100)
30 #define IWL_CHANNEL_TUNE_TIME       5
31 #define MAX_SCAN_CHANNEL	    50
32 
33 /* For reset radio, need minimal dwell time only */
34 #define IWL_RADIO_RESET_DWELL_TIME	5
35 
36 static int iwl_send_scan_abort(struct iwl_priv *priv)
37 {
38 	int ret;
39 	struct iwl_host_cmd cmd = {
40 		.id = REPLY_SCAN_ABORT_CMD,
41 		.flags = CMD_WANT_SKB,
42 	};
43 	__le32 *status;
44 
45 	/* Exit instantly with error when device is not ready
46 	 * to receive scan abort command or it does not perform
47 	 * hardware scan currently */
48 	if (!test_bit(STATUS_READY, &priv->status) ||
49 	    !test_bit(STATUS_SCAN_HW, &priv->status) ||
50 	    test_bit(STATUS_FW_ERROR, &priv->status))
51 		return -EIO;
52 
53 	ret = iwl_dvm_send_cmd(priv, &cmd);
54 	if (ret)
55 		return ret;
56 
57 	status = (void *)cmd.resp_pkt->data;
58 	if (*status != CAN_ABORT_STATUS) {
59 		/* The scan abort will return 1 for success or
60 		 * 2 for "failure".  A failure condition can be
61 		 * due to simply not being in an active scan which
62 		 * can occur if we send the scan abort before we
63 		 * the microcode has notified us that a scan is
64 		 * completed. */
65 		IWL_DEBUG_SCAN(priv, "SCAN_ABORT ret %d.\n",
66 			       le32_to_cpu(*status));
67 		ret = -EIO;
68 	}
69 
70 	iwl_free_resp(&cmd);
71 	return ret;
72 }
73 
74 static void iwl_complete_scan(struct iwl_priv *priv, bool aborted)
75 {
76 	struct cfg80211_scan_info info = {
77 		.aborted = aborted,
78 	};
79 
80 	/* check if scan was requested from mac80211 */
81 	if (priv->scan_request) {
82 		IWL_DEBUG_SCAN(priv, "Complete scan in mac80211\n");
83 		ieee80211_scan_completed(priv->hw, &info);
84 	}
85 
86 	priv->scan_type = IWL_SCAN_NORMAL;
87 	priv->scan_vif = NULL;
88 	priv->scan_request = NULL;
89 }
90 
91 static void iwl_process_scan_complete(struct iwl_priv *priv)
92 {
93 	bool aborted;
94 
95 	lockdep_assert_held(&priv->mutex);
96 
97 	if (!test_and_clear_bit(STATUS_SCAN_COMPLETE, &priv->status))
98 		return;
99 
100 	IWL_DEBUG_SCAN(priv, "Completed scan.\n");
101 
102 	cancel_delayed_work(&priv->scan_check);
103 
104 	aborted = test_and_clear_bit(STATUS_SCAN_ABORTING, &priv->status);
105 	if (aborted)
106 		IWL_DEBUG_SCAN(priv, "Aborted scan completed.\n");
107 
108 	if (!test_and_clear_bit(STATUS_SCANNING, &priv->status)) {
109 		IWL_DEBUG_SCAN(priv, "Scan already completed.\n");
110 		goto out_settings;
111 	}
112 
113 	if (priv->scan_type != IWL_SCAN_NORMAL && !aborted) {
114 		int err;
115 
116 		/* Check if mac80211 requested scan during our internal scan */
117 		if (priv->scan_request == NULL)
118 			goto out_complete;
119 
120 		/* If so request a new scan */
121 		err = iwl_scan_initiate(priv, priv->scan_vif, IWL_SCAN_NORMAL,
122 					priv->scan_request->channels[0]->band);
123 		if (err) {
124 			IWL_DEBUG_SCAN(priv,
125 				"failed to initiate pending scan: %d\n", err);
126 			aborted = true;
127 			goto out_complete;
128 		}
129 
130 		return;
131 	}
132 
133 out_complete:
134 	iwl_complete_scan(priv, aborted);
135 
136 out_settings:
137 	/* Can we still talk to firmware ? */
138 	if (!iwl_is_ready_rf(priv))
139 		return;
140 
141 	iwlagn_post_scan(priv);
142 }
143 
144 void iwl_force_scan_end(struct iwl_priv *priv)
145 {
146 	lockdep_assert_held(&priv->mutex);
147 
148 	if (!test_bit(STATUS_SCANNING, &priv->status)) {
149 		IWL_DEBUG_SCAN(priv, "Forcing scan end while not scanning\n");
150 		return;
151 	}
152 
153 	IWL_DEBUG_SCAN(priv, "Forcing scan end\n");
154 	clear_bit(STATUS_SCANNING, &priv->status);
155 	clear_bit(STATUS_SCAN_HW, &priv->status);
156 	clear_bit(STATUS_SCAN_ABORTING, &priv->status);
157 	clear_bit(STATUS_SCAN_COMPLETE, &priv->status);
158 	iwl_complete_scan(priv, true);
159 }
160 
161 static void iwl_do_scan_abort(struct iwl_priv *priv)
162 {
163 	int ret;
164 
165 	lockdep_assert_held(&priv->mutex);
166 
167 	if (!test_bit(STATUS_SCANNING, &priv->status)) {
168 		IWL_DEBUG_SCAN(priv, "Not performing scan to abort\n");
169 		return;
170 	}
171 
172 	if (test_and_set_bit(STATUS_SCAN_ABORTING, &priv->status)) {
173 		IWL_DEBUG_SCAN(priv, "Scan abort in progress\n");
174 		return;
175 	}
176 
177 	ret = iwl_send_scan_abort(priv);
178 	if (ret) {
179 		IWL_DEBUG_SCAN(priv, "Send scan abort failed %d\n", ret);
180 		iwl_force_scan_end(priv);
181 	} else
182 		IWL_DEBUG_SCAN(priv, "Successfully send scan abort\n");
183 }
184 
185 /*
186  * iwl_scan_cancel - Cancel any currently executing HW scan
187  */
188 int iwl_scan_cancel(struct iwl_priv *priv)
189 {
190 	IWL_DEBUG_SCAN(priv, "Queuing abort scan\n");
191 	queue_work(priv->workqueue, &priv->abort_scan);
192 	return 0;
193 }
194 
195 /*
196  * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
197  * @ms: amount of time to wait (in milliseconds) for scan to abort
198  */
199 void iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
200 {
201 	unsigned long timeout = jiffies + msecs_to_jiffies(ms);
202 
203 	lockdep_assert_held(&priv->mutex);
204 
205 	IWL_DEBUG_SCAN(priv, "Scan cancel timeout\n");
206 
207 	iwl_do_scan_abort(priv);
208 
209 	while (time_before_eq(jiffies, timeout)) {
210 		if (!test_bit(STATUS_SCAN_HW, &priv->status))
211 			goto finished;
212 		msleep(20);
213 	}
214 
215 	return;
216 
217  finished:
218 	/*
219 	 * Now STATUS_SCAN_HW is clear. This means that the
220 	 * device finished, but the background work is going
221 	 * to execute at best as soon as we release the mutex.
222 	 * Since we need to be able to issue a new scan right
223 	 * after this function returns, run the complete here.
224 	 * The STATUS_SCAN_COMPLETE bit will then be cleared
225 	 * and prevent the background work from "completing"
226 	 * a possible new scan.
227 	 */
228 	iwl_process_scan_complete(priv);
229 }
230 
231 /* Service response to REPLY_SCAN_CMD (0x80) */
232 static void iwl_rx_reply_scan(struct iwl_priv *priv,
233 			      struct iwl_rx_cmd_buffer *rxb)
234 {
235 #ifdef CONFIG_IWLWIFI_DEBUG
236 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
237 	struct iwl_scanreq_notification *notif = (void *)pkt->data;
238 
239 	IWL_DEBUG_SCAN(priv, "Scan request status = 0x%x\n", notif->status);
240 #endif
241 }
242 
243 /* Service SCAN_START_NOTIFICATION (0x82) */
244 static void iwl_rx_scan_start_notif(struct iwl_priv *priv,
245 				    struct iwl_rx_cmd_buffer *rxb)
246 {
247 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
248 	struct iwl_scanstart_notification *notif = (void *)pkt->data;
249 
250 	priv->scan_start_tsf = le32_to_cpu(notif->tsf_low);
251 	IWL_DEBUG_SCAN(priv, "Scan start: "
252 		       "%d [802.11%s] "
253 		       "(TSF: 0x%08X:%08X) - %d (beacon timer %u)\n",
254 		       notif->channel,
255 		       notif->band ? "bg" : "a",
256 		       le32_to_cpu(notif->tsf_high),
257 		       le32_to_cpu(notif->tsf_low),
258 		       notif->status, notif->beacon_timer);
259 }
260 
261 /* Service SCAN_RESULTS_NOTIFICATION (0x83) */
262 static void iwl_rx_scan_results_notif(struct iwl_priv *priv,
263 				      struct iwl_rx_cmd_buffer *rxb)
264 {
265 #ifdef CONFIG_IWLWIFI_DEBUG
266 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
267 	struct iwl_scanresults_notification *notif = (void *)pkt->data;
268 
269 	IWL_DEBUG_SCAN(priv, "Scan ch.res: "
270 		       "%d [802.11%s] "
271 		       "probe status: %u:%u "
272 		       "(TSF: 0x%08X:%08X) - %d "
273 		       "elapsed=%lu usec\n",
274 		       notif->channel,
275 		       notif->band ? "bg" : "a",
276 		       notif->probe_status, notif->num_probe_not_sent,
277 		       le32_to_cpu(notif->tsf_high),
278 		       le32_to_cpu(notif->tsf_low),
279 		       le32_to_cpu(notif->statistics[0]),
280 		       le32_to_cpu(notif->tsf_low) - priv->scan_start_tsf);
281 #endif
282 }
283 
284 /* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
285 static void iwl_rx_scan_complete_notif(struct iwl_priv *priv,
286 				       struct iwl_rx_cmd_buffer *rxb)
287 {
288 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
289 	struct iwl_scancomplete_notification *scan_notif = (void *)pkt->data;
290 
291 	IWL_DEBUG_SCAN(priv, "Scan complete: %d channels (TSF 0x%08X:%08X) - %d\n",
292 		       scan_notif->scanned_channels,
293 		       scan_notif->tsf_low,
294 		       scan_notif->tsf_high, scan_notif->status);
295 
296 	IWL_DEBUG_SCAN(priv, "Scan on %sGHz took %dms\n",
297 		       (priv->scan_band == NL80211_BAND_2GHZ) ? "2.4" : "5.2",
298 		       jiffies_to_msecs(jiffies - priv->scan_start));
299 
300 	/*
301 	 * When aborting, we run the scan completed background work inline
302 	 * and the background work must then do nothing. The SCAN_COMPLETE
303 	 * bit helps implement that logic and thus needs to be set before
304 	 * queueing the work. Also, since the scan abort waits for SCAN_HW
305 	 * to clear, we need to set SCAN_COMPLETE before clearing SCAN_HW
306 	 * to avoid a race there.
307 	 */
308 	set_bit(STATUS_SCAN_COMPLETE, &priv->status);
309 	clear_bit(STATUS_SCAN_HW, &priv->status);
310 	queue_work(priv->workqueue, &priv->scan_completed);
311 
312 	if (priv->iw_mode != NL80211_IFTYPE_ADHOC &&
313 	    iwl_advanced_bt_coexist(priv) &&
314 	    priv->bt_status != scan_notif->bt_status) {
315 		if (scan_notif->bt_status) {
316 			/* BT on */
317 			if (!priv->bt_ch_announce)
318 				priv->bt_traffic_load =
319 					IWL_BT_COEX_TRAFFIC_LOAD_HIGH;
320 			/*
321 			 * otherwise, no traffic load information provided
322 			 * no changes made
323 			 */
324 		} else {
325 			/* BT off */
326 			priv->bt_traffic_load =
327 				IWL_BT_COEX_TRAFFIC_LOAD_NONE;
328 		}
329 		priv->bt_status = scan_notif->bt_status;
330 		queue_work(priv->workqueue,
331 			   &priv->bt_traffic_change_work);
332 	}
333 }
334 
335 void iwl_setup_rx_scan_handlers(struct iwl_priv *priv)
336 {
337 	/* scan handlers */
338 	priv->rx_handlers[REPLY_SCAN_CMD] = iwl_rx_reply_scan;
339 	priv->rx_handlers[SCAN_START_NOTIFICATION] = iwl_rx_scan_start_notif;
340 	priv->rx_handlers[SCAN_RESULTS_NOTIFICATION] =
341 					iwl_rx_scan_results_notif;
342 	priv->rx_handlers[SCAN_COMPLETE_NOTIFICATION] =
343 					iwl_rx_scan_complete_notif;
344 }
345 
346 static u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
347 				     enum nl80211_band band, u8 n_probes)
348 {
349 	if (band == NL80211_BAND_5GHZ)
350 		return IWL_ACTIVE_DWELL_TIME_52 +
351 			IWL_ACTIVE_DWELL_FACTOR_52GHZ * (n_probes + 1);
352 	else
353 		return IWL_ACTIVE_DWELL_TIME_24 +
354 			IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
355 }
356 
357 static u16 iwl_limit_dwell(struct iwl_priv *priv, u16 dwell_time)
358 {
359 	struct iwl_rxon_context *ctx;
360 	int limits[NUM_IWL_RXON_CTX] = {};
361 	int n_active = 0;
362 	u16 limit;
363 
364 	BUILD_BUG_ON(NUM_IWL_RXON_CTX != 2);
365 
366 	/*
367 	 * If we're associated, we clamp the dwell time 98%
368 	 * of the beacon interval (minus 2 * channel tune time)
369 	 * If both contexts are active, we have to restrict to
370 	 * 1/2 of the minimum of them, because they might be in
371 	 * lock-step with the time inbetween only half of what
372 	 * time we'd have in each of them.
373 	 */
374 	for_each_context(priv, ctx) {
375 		switch (ctx->staging.dev_type) {
376 		case RXON_DEV_TYPE_P2P:
377 			/* no timing constraints */
378 			continue;
379 		case RXON_DEV_TYPE_ESS:
380 		default:
381 			/* timing constraints if associated */
382 			if (!iwl_is_associated_ctx(ctx))
383 				continue;
384 			break;
385 		case RXON_DEV_TYPE_CP:
386 		case RXON_DEV_TYPE_2STA:
387 			/*
388 			 * These seem to always have timers for TBTT
389 			 * active in uCode even when not associated yet.
390 			 */
391 			break;
392 		}
393 
394 		limits[n_active++] = ctx->beacon_int ?: IWL_PASSIVE_DWELL_BASE;
395 	}
396 
397 	switch (n_active) {
398 	case 0:
399 		return dwell_time;
400 	case 2:
401 		limit = (limits[1] * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
402 		limit /= 2;
403 		dwell_time = min(limit, dwell_time);
404 		fallthrough;
405 	case 1:
406 		limit = (limits[0] * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
407 		limit /= n_active;
408 		return min(limit, dwell_time);
409 	default:
410 		WARN_ON_ONCE(1);
411 		return dwell_time;
412 	}
413 }
414 
415 static u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
416 				      enum nl80211_band band)
417 {
418 	u16 passive = (band == NL80211_BAND_2GHZ) ?
419 	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
420 	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;
421 
422 	return iwl_limit_dwell(priv, passive);
423 }
424 
425 /* Return valid, unused, channel for a passive scan to reset the RF */
426 static u8 iwl_get_single_channel_number(struct iwl_priv *priv,
427 					enum nl80211_band band)
428 {
429 	struct ieee80211_supported_band *sband = priv->hw->wiphy->bands[band];
430 	struct iwl_rxon_context *ctx;
431 	int i;
432 
433 	for (i = 0; i < sband->n_channels; i++) {
434 		bool busy = false;
435 
436 		for_each_context(priv, ctx) {
437 			busy = sband->channels[i].hw_value ==
438 				le16_to_cpu(ctx->staging.channel);
439 			if (busy)
440 				break;
441 		}
442 
443 		if (busy)
444 			continue;
445 
446 		if (!(sband->channels[i].flags & IEEE80211_CHAN_DISABLED))
447 			return sband->channels[i].hw_value;
448 	}
449 
450 	return 0;
451 }
452 
453 static int iwl_get_channel_for_reset_scan(struct iwl_priv *priv,
454 					  struct ieee80211_vif *vif,
455 					  enum nl80211_band band,
456 					  struct iwl_scan_channel *scan_ch)
457 {
458 	const struct ieee80211_supported_band *sband;
459 	u16 channel;
460 
461 	sband = iwl_get_hw_mode(priv, band);
462 	if (!sband) {
463 		IWL_ERR(priv, "invalid band\n");
464 		return 0;
465 	}
466 
467 	channel = iwl_get_single_channel_number(priv, band);
468 	if (channel) {
469 		scan_ch->channel = cpu_to_le16(channel);
470 		scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
471 		scan_ch->active_dwell =
472 			cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
473 		scan_ch->passive_dwell =
474 			cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
475 		/* Set txpower levels to defaults */
476 		scan_ch->dsp_atten = 110;
477 		if (band == NL80211_BAND_5GHZ)
478 			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
479 		else
480 			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
481 		return 1;
482 	}
483 
484 	IWL_ERR(priv, "no valid channel found\n");
485 	return 0;
486 }
487 
488 static int iwl_get_channels_for_scan(struct iwl_priv *priv,
489 				     struct ieee80211_vif *vif,
490 				     enum nl80211_band band,
491 				     u8 is_active, u8 n_probes,
492 				     struct iwl_scan_channel *scan_ch)
493 {
494 	struct ieee80211_channel *chan;
495 	const struct ieee80211_supported_band *sband;
496 	u16 passive_dwell = 0;
497 	u16 active_dwell = 0;
498 	int added, i;
499 	u16 channel;
500 
501 	sband = iwl_get_hw_mode(priv, band);
502 	if (!sband)
503 		return 0;
504 
505 	active_dwell = iwl_get_active_dwell_time(priv, band, n_probes);
506 	passive_dwell = iwl_get_passive_dwell_time(priv, band);
507 
508 	if (passive_dwell <= active_dwell)
509 		passive_dwell = active_dwell + 1;
510 
511 	for (i = 0, added = 0; i < priv->scan_request->n_channels; i++) {
512 		chan = priv->scan_request->channels[i];
513 
514 		if (chan->band != band)
515 			continue;
516 
517 		channel = chan->hw_value;
518 		scan_ch->channel = cpu_to_le16(channel);
519 
520 		if (!is_active || (chan->flags & IEEE80211_CHAN_NO_IR))
521 			scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
522 		else
523 			scan_ch->type = SCAN_CHANNEL_TYPE_ACTIVE;
524 
525 		if (n_probes)
526 			scan_ch->type |= IWL_SCAN_PROBE_MASK(n_probes);
527 
528 		scan_ch->active_dwell = cpu_to_le16(active_dwell);
529 		scan_ch->passive_dwell = cpu_to_le16(passive_dwell);
530 
531 		/* Set txpower levels to defaults */
532 		scan_ch->dsp_atten = 110;
533 
534 		/* NOTE: if we were doing 6Mb OFDM for scans we'd use
535 		 * power level:
536 		 * scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
537 		 */
538 		if (band == NL80211_BAND_5GHZ)
539 			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
540 		else
541 			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
542 
543 		IWL_DEBUG_SCAN(priv, "Scanning ch=%d prob=0x%X [%s %d]\n",
544 			       channel, le32_to_cpu(scan_ch->type),
545 			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
546 				"ACTIVE" : "PASSIVE",
547 			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
548 			       active_dwell : passive_dwell);
549 
550 		scan_ch++;
551 		added++;
552 	}
553 
554 	IWL_DEBUG_SCAN(priv, "total channels to scan %d\n", added);
555 	return added;
556 }
557 
558 /*
559  * iwl_fill_probe_req - fill in all required fields and IE for probe request
560  */
561 static u16 iwl_fill_probe_req(struct ieee80211_mgmt *frame, const u8 *ta,
562 			      const u8 *ies, int ie_len, const u8 *ssid,
563 			      u8 ssid_len, int left)
564 {
565 	int len = 0;
566 	u8 *pos = NULL;
567 
568 	/* Make sure there is enough space for the probe request,
569 	 * two mandatory IEs and the data */
570 	left -= 24;
571 	if (left < 0)
572 		return 0;
573 
574 	frame->frame_control = cpu_to_le16(IEEE80211_STYPE_PROBE_REQ);
575 	eth_broadcast_addr(frame->da);
576 	memcpy(frame->sa, ta, ETH_ALEN);
577 	eth_broadcast_addr(frame->bssid);
578 	frame->seq_ctrl = 0;
579 
580 	len += 24;
581 
582 	/* ...next IE... */
583 	pos = &frame->u.probe_req.variable[0];
584 
585 	/* fill in our SSID IE */
586 	left -= ssid_len + 2;
587 	if (left < 0)
588 		return 0;
589 	*pos++ = WLAN_EID_SSID;
590 	*pos++ = ssid_len;
591 	if (ssid && ssid_len) {
592 		memcpy(pos, ssid, ssid_len);
593 		pos += ssid_len;
594 	}
595 
596 	len += ssid_len + 2;
597 
598 	if (WARN_ON(left < ie_len))
599 		return len;
600 
601 	if (ies && ie_len) {
602 		memcpy(pos, ies, ie_len);
603 		len += ie_len;
604 	}
605 
606 	return (u16)len;
607 }
608 
609 static int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
610 {
611 	struct iwl_host_cmd cmd = {
612 		.id = REPLY_SCAN_CMD,
613 		.len = { sizeof(struct iwl_scan_cmd), },
614 	};
615 	struct iwl_scan_cmd *scan;
616 	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
617 	u32 rate_flags = 0;
618 	u16 cmd_len = 0;
619 	u16 rx_chain = 0;
620 	enum nl80211_band band;
621 	u8 n_probes = 0;
622 	u8 rx_ant = priv->nvm_data->valid_rx_ant;
623 	u8 rate;
624 	bool is_active = false;
625 	int  chan_mod;
626 	u8 active_chains;
627 	u8 scan_tx_antennas = priv->nvm_data->valid_tx_ant;
628 	int ret;
629 	size_t scan_cmd_size = sizeof(struct iwl_scan_cmd) +
630 			    MAX_SCAN_CHANNEL * sizeof(struct iwl_scan_channel) +
631 			    priv->fw->ucode_capa.max_probe_length;
632 	const u8 *ssid = NULL;
633 	u8 ssid_len = 0;
634 
635 	if (WARN_ON(priv->scan_type == IWL_SCAN_NORMAL &&
636 		    (!priv->scan_request ||
637 		     priv->scan_request->n_channels > MAX_SCAN_CHANNEL)))
638 		return -EINVAL;
639 
640 	lockdep_assert_held(&priv->mutex);
641 
642 	if (vif)
643 		ctx = iwl_rxon_ctx_from_vif(vif);
644 
645 	if (!priv->scan_cmd) {
646 		priv->scan_cmd = kmalloc(scan_cmd_size, GFP_KERNEL);
647 		if (!priv->scan_cmd) {
648 			IWL_DEBUG_SCAN(priv,
649 				       "fail to allocate memory for scan\n");
650 			return -ENOMEM;
651 		}
652 		priv->scan_cmd_size = scan_cmd_size;
653 	}
654 	if (priv->scan_cmd_size < scan_cmd_size) {
655 		IWL_DEBUG_SCAN(priv,
656 			       "memory needed for scan grew unexpectedly\n");
657 		return -ENOMEM;
658 	}
659 	scan = priv->scan_cmd;
660 	memset(scan, 0, priv->scan_cmd_size);
661 
662 	scan->quiet_plcp_th = IWL_PLCP_QUIET_THRESH;
663 	scan->quiet_time = IWL_ACTIVE_QUIET_TIME;
664 
665 	if (iwl_is_any_associated(priv)) {
666 		u16 interval = 0;
667 		u32 extra;
668 		u32 suspend_time = 100;
669 		u32 scan_suspend_time = 100;
670 
671 		IWL_DEBUG_INFO(priv, "Scanning while associated...\n");
672 		switch (priv->scan_type) {
673 		case IWL_SCAN_RADIO_RESET:
674 			interval = 0;
675 			break;
676 		case IWL_SCAN_NORMAL:
677 			interval = vif->bss_conf.beacon_int;
678 			break;
679 		}
680 
681 		scan->suspend_time = 0;
682 		scan->max_out_time = cpu_to_le32(200 * 1024);
683 		if (!interval)
684 			interval = suspend_time;
685 
686 		extra = (suspend_time / interval) << 22;
687 		scan_suspend_time = (extra |
688 		    ((suspend_time % interval) * 1024));
689 		scan->suspend_time = cpu_to_le32(scan_suspend_time);
690 		IWL_DEBUG_SCAN(priv, "suspend_time 0x%X beacon interval %d\n",
691 			       scan_suspend_time, interval);
692 	}
693 
694 	switch (priv->scan_type) {
695 	case IWL_SCAN_RADIO_RESET:
696 		IWL_DEBUG_SCAN(priv, "Start internal passive scan.\n");
697 		/*
698 		 * Override quiet time as firmware checks that active
699 		 * dwell is >= quiet; since we use passive scan it'll
700 		 * not actually be used.
701 		 */
702 		scan->quiet_time = cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
703 		break;
704 	case IWL_SCAN_NORMAL:
705 		if (priv->scan_request->n_ssids) {
706 			int i, p = 0;
707 			IWL_DEBUG_SCAN(priv, "Kicking off active scan\n");
708 			/*
709 			 * The highest priority SSID is inserted to the
710 			 * probe request template.
711 			 */
712 			ssid_len = priv->scan_request->ssids[0].ssid_len;
713 			ssid = priv->scan_request->ssids[0].ssid;
714 
715 			/*
716 			 * Invert the order of ssids, the firmware will invert
717 			 * it back.
718 			 */
719 			for (i = priv->scan_request->n_ssids - 1; i >= 1; i--) {
720 				scan->direct_scan[p].id = WLAN_EID_SSID;
721 				scan->direct_scan[p].len =
722 					priv->scan_request->ssids[i].ssid_len;
723 				memcpy(scan->direct_scan[p].ssid,
724 				       priv->scan_request->ssids[i].ssid,
725 				       priv->scan_request->ssids[i].ssid_len);
726 				n_probes++;
727 				p++;
728 			}
729 			is_active = true;
730 		} else
731 			IWL_DEBUG_SCAN(priv, "Start passive scan.\n");
732 		break;
733 	}
734 
735 	scan->tx_cmd.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK;
736 	scan->tx_cmd.sta_id = ctx->bcast_sta_id;
737 	scan->tx_cmd.stop_time.life_time = TX_CMD_LIFE_TIME_INFINITE;
738 
739 	switch (priv->scan_band) {
740 	case NL80211_BAND_2GHZ:
741 		scan->flags = RXON_FLG_BAND_24G_MSK | RXON_FLG_AUTO_DETECT_MSK;
742 		chan_mod = le32_to_cpu(
743 			priv->contexts[IWL_RXON_CTX_BSS].active.flags &
744 						RXON_FLG_CHANNEL_MODE_MSK)
745 				       >> RXON_FLG_CHANNEL_MODE_POS;
746 		if ((priv->scan_request && priv->scan_request->no_cck) ||
747 		    chan_mod == CHANNEL_MODE_PURE_40) {
748 			rate = IWL_RATE_6M_PLCP;
749 		} else {
750 			rate = IWL_RATE_1M_PLCP;
751 			rate_flags = RATE_MCS_CCK_MSK;
752 		}
753 		/*
754 		 * Internal scans are passive, so we can indiscriminately set
755 		 * the BT ignore flag on 2.4 GHz since it applies to TX only.
756 		 */
757 		if (priv->lib->bt_params &&
758 		    priv->lib->bt_params->advanced_bt_coexist)
759 			scan->tx_cmd.tx_flags |= TX_CMD_FLG_IGNORE_BT;
760 		break;
761 	case NL80211_BAND_5GHZ:
762 		rate = IWL_RATE_6M_PLCP;
763 		break;
764 	default:
765 		IWL_WARN(priv, "Invalid scan band\n");
766 		return -EIO;
767 	}
768 
769 	/*
770 	 * If active scanning is requested but a certain channel is
771 	 * marked passive, we can do active scanning if we detect
772 	 * transmissions.
773 	 *
774 	 * There is an issue with some firmware versions that triggers
775 	 * a sysassert on a "good CRC threshold" of zero (== disabled),
776 	 * on a radar channel even though this means that we should NOT
777 	 * send probes.
778 	 *
779 	 * The "good CRC threshold" is the number of frames that we
780 	 * need to receive during our dwell time on a channel before
781 	 * sending out probes -- setting this to a huge value will
782 	 * mean we never reach it, but at the same time work around
783 	 * the aforementioned issue. Thus use IWL_GOOD_CRC_TH_NEVER
784 	 * here instead of IWL_GOOD_CRC_TH_DISABLED.
785 	 *
786 	 * This was fixed in later versions along with some other
787 	 * scan changes, and the threshold behaves as a flag in those
788 	 * versions.
789 	 */
790 	if (priv->new_scan_threshold_behaviour)
791 		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
792 						IWL_GOOD_CRC_TH_DISABLED;
793 	else
794 		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
795 						IWL_GOOD_CRC_TH_NEVER;
796 
797 	band = priv->scan_band;
798 
799 	if (band == NL80211_BAND_2GHZ &&
800 	    priv->lib->bt_params &&
801 	    priv->lib->bt_params->advanced_bt_coexist) {
802 		/* transmit 2.4 GHz probes only on first antenna */
803 		scan_tx_antennas = first_antenna(scan_tx_antennas);
804 	}
805 
806 	priv->scan_tx_ant[band] = iwl_toggle_tx_ant(priv,
807 						    priv->scan_tx_ant[band],
808 						    scan_tx_antennas);
809 	rate_flags |= iwl_ant_idx_to_flags(priv->scan_tx_ant[band]);
810 	scan->tx_cmd.rate_n_flags = iwl_hw_set_rate_n_flags(rate, rate_flags);
811 
812 	/*
813 	 * In power save mode while associated use one chain,
814 	 * otherwise use all chains
815 	 */
816 	if (test_bit(STATUS_POWER_PMI, &priv->status) &&
817 	    !(priv->hw->conf.flags & IEEE80211_CONF_IDLE)) {
818 		/* rx_ant has been set to all valid chains previously */
819 		active_chains = rx_ant &
820 				((u8)(priv->chain_noise_data.active_chains));
821 		if (!active_chains)
822 			active_chains = rx_ant;
823 
824 		IWL_DEBUG_SCAN(priv, "chain_noise_data.active_chains: %u\n",
825 				priv->chain_noise_data.active_chains);
826 
827 		rx_ant = first_antenna(active_chains);
828 	}
829 	if (priv->lib->bt_params &&
830 	    priv->lib->bt_params->advanced_bt_coexist &&
831 	    priv->bt_full_concurrent) {
832 		/* operated as 1x1 in full concurrency mode */
833 		rx_ant = first_antenna(rx_ant);
834 	}
835 
836 	/* MIMO is not used here, but value is required */
837 	rx_chain |=
838 		priv->nvm_data->valid_rx_ant << RXON_RX_CHAIN_VALID_POS;
839 	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_MIMO_SEL_POS;
840 	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_SEL_POS;
841 	rx_chain |= 0x1 << RXON_RX_CHAIN_DRIVER_FORCE_POS;
842 	scan->rx_chain = cpu_to_le16(rx_chain);
843 	switch (priv->scan_type) {
844 	case IWL_SCAN_NORMAL:
845 		cmd_len = iwl_fill_probe_req(
846 					(struct ieee80211_mgmt *)scan->data,
847 					vif->addr,
848 					priv->scan_request->ie,
849 					priv->scan_request->ie_len,
850 					ssid, ssid_len,
851 					scan_cmd_size - sizeof(*scan));
852 		break;
853 	case IWL_SCAN_RADIO_RESET:
854 		/* use bcast addr, will not be transmitted but must be valid */
855 		cmd_len = iwl_fill_probe_req(
856 					(struct ieee80211_mgmt *)scan->data,
857 					iwl_bcast_addr, NULL, 0,
858 					NULL, 0,
859 					scan_cmd_size - sizeof(*scan));
860 		break;
861 	default:
862 		BUG();
863 	}
864 	scan->tx_cmd.len = cpu_to_le16(cmd_len);
865 
866 	scan->filter_flags |= (RXON_FILTER_ACCEPT_GRP_MSK |
867 			       RXON_FILTER_BCON_AWARE_MSK);
868 
869 	switch (priv->scan_type) {
870 	case IWL_SCAN_RADIO_RESET:
871 		scan->channel_count =
872 			iwl_get_channel_for_reset_scan(priv, vif, band,
873 				(void *)&scan->data[cmd_len]);
874 		break;
875 	case IWL_SCAN_NORMAL:
876 		scan->channel_count =
877 			iwl_get_channels_for_scan(priv, vif, band,
878 				is_active, n_probes,
879 				(void *)&scan->data[cmd_len]);
880 		break;
881 	}
882 
883 	if (scan->channel_count == 0) {
884 		IWL_DEBUG_SCAN(priv, "channel count %d\n", scan->channel_count);
885 		return -EIO;
886 	}
887 
888 	cmd.len[0] += le16_to_cpu(scan->tx_cmd.len) +
889 	    scan->channel_count * sizeof(struct iwl_scan_channel);
890 	cmd.data[0] = scan;
891 	cmd.dataflags[0] = IWL_HCMD_DFL_NOCOPY;
892 	scan->len = cpu_to_le16(cmd.len[0]);
893 
894 	/* set scan bit here for PAN params */
895 	set_bit(STATUS_SCAN_HW, &priv->status);
896 
897 	ret = iwlagn_set_pan_params(priv);
898 	if (ret) {
899 		clear_bit(STATUS_SCAN_HW, &priv->status);
900 		return ret;
901 	}
902 
903 	ret = iwl_dvm_send_cmd(priv, &cmd);
904 	if (ret) {
905 		clear_bit(STATUS_SCAN_HW, &priv->status);
906 		iwlagn_set_pan_params(priv);
907 	}
908 
909 	return ret;
910 }
911 
912 void iwl_init_scan_params(struct iwl_priv *priv)
913 {
914 	u8 ant_idx = fls(priv->nvm_data->valid_tx_ant) - 1;
915 	if (!priv->scan_tx_ant[NL80211_BAND_5GHZ])
916 		priv->scan_tx_ant[NL80211_BAND_5GHZ] = ant_idx;
917 	if (!priv->scan_tx_ant[NL80211_BAND_2GHZ])
918 		priv->scan_tx_ant[NL80211_BAND_2GHZ] = ant_idx;
919 }
920 
921 int __must_check iwl_scan_initiate(struct iwl_priv *priv,
922 				   struct ieee80211_vif *vif,
923 				   enum iwl_scan_type scan_type,
924 				   enum nl80211_band band)
925 {
926 	int ret;
927 
928 	lockdep_assert_held(&priv->mutex);
929 
930 	cancel_delayed_work(&priv->scan_check);
931 
932 	if (!iwl_is_ready_rf(priv)) {
933 		IWL_WARN(priv, "Request scan called when driver not ready.\n");
934 		return -EIO;
935 	}
936 
937 	if (test_bit(STATUS_SCAN_HW, &priv->status)) {
938 		IWL_DEBUG_SCAN(priv,
939 			"Multiple concurrent scan requests in parallel.\n");
940 		return -EBUSY;
941 	}
942 
943 	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
944 		IWL_DEBUG_SCAN(priv, "Scan request while abort pending.\n");
945 		return -EBUSY;
946 	}
947 
948 	IWL_DEBUG_SCAN(priv, "Starting %sscan...\n",
949 			scan_type == IWL_SCAN_NORMAL ? "" :
950 			"internal short ");
951 
952 	set_bit(STATUS_SCANNING, &priv->status);
953 	priv->scan_type = scan_type;
954 	priv->scan_start = jiffies;
955 	priv->scan_band = band;
956 
957 	ret = iwlagn_request_scan(priv, vif);
958 	if (ret) {
959 		clear_bit(STATUS_SCANNING, &priv->status);
960 		priv->scan_type = IWL_SCAN_NORMAL;
961 		return ret;
962 	}
963 
964 	queue_delayed_work(priv->workqueue, &priv->scan_check,
965 			   IWL_SCAN_CHECK_WATCHDOG);
966 
967 	return 0;
968 }
969 
970 
971 /*
972  * internal short scan, this function should only been called while associated.
973  * It will reset and tune the radio to prevent possible RF related problem
974  */
975 void iwl_internal_short_hw_scan(struct iwl_priv *priv)
976 {
977 	queue_work(priv->workqueue, &priv->start_internal_scan);
978 }
979 
980 static void iwl_bg_start_internal_scan(struct work_struct *work)
981 {
982 	struct iwl_priv *priv =
983 		container_of(work, struct iwl_priv, start_internal_scan);
984 
985 	IWL_DEBUG_SCAN(priv, "Start internal scan\n");
986 
987 	mutex_lock(&priv->mutex);
988 
989 	if (priv->scan_type == IWL_SCAN_RADIO_RESET) {
990 		IWL_DEBUG_SCAN(priv, "Internal scan already in progress\n");
991 		goto unlock;
992 	}
993 
994 	if (test_bit(STATUS_SCANNING, &priv->status)) {
995 		IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
996 		goto unlock;
997 	}
998 
999 	if (iwl_scan_initiate(priv, NULL, IWL_SCAN_RADIO_RESET, priv->band))
1000 		IWL_DEBUG_SCAN(priv, "failed to start internal short scan\n");
1001  unlock:
1002 	mutex_unlock(&priv->mutex);
1003 }
1004 
1005 static void iwl_bg_scan_check(struct work_struct *data)
1006 {
1007 	struct iwl_priv *priv =
1008 	    container_of(data, struct iwl_priv, scan_check.work);
1009 
1010 	IWL_DEBUG_SCAN(priv, "Scan check work\n");
1011 
1012 	/* Since we are here firmware does not finish scan and
1013 	 * most likely is in bad shape, so we don't bother to
1014 	 * send abort command, just force scan complete to mac80211 */
1015 	mutex_lock(&priv->mutex);
1016 	iwl_force_scan_end(priv);
1017 	mutex_unlock(&priv->mutex);
1018 }
1019 
1020 static void iwl_bg_abort_scan(struct work_struct *work)
1021 {
1022 	struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);
1023 
1024 	IWL_DEBUG_SCAN(priv, "Abort scan work\n");
1025 
1026 	/* We keep scan_check work queued in case when firmware will not
1027 	 * report back scan completed notification */
1028 	mutex_lock(&priv->mutex);
1029 	iwl_scan_cancel_timeout(priv, 200);
1030 	mutex_unlock(&priv->mutex);
1031 }
1032 
1033 static void iwl_bg_scan_completed(struct work_struct *work)
1034 {
1035 	struct iwl_priv *priv =
1036 		container_of(work, struct iwl_priv, scan_completed);
1037 
1038 	mutex_lock(&priv->mutex);
1039 	iwl_process_scan_complete(priv);
1040 	mutex_unlock(&priv->mutex);
1041 }
1042 
1043 void iwl_setup_scan_deferred_work(struct iwl_priv *priv)
1044 {
1045 	INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed);
1046 	INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
1047 	INIT_WORK(&priv->start_internal_scan, iwl_bg_start_internal_scan);
1048 	INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
1049 }
1050 
1051 void iwl_cancel_scan_deferred_work(struct iwl_priv *priv)
1052 {
1053 	cancel_work_sync(&priv->start_internal_scan);
1054 	cancel_work_sync(&priv->abort_scan);
1055 	cancel_work_sync(&priv->scan_completed);
1056 
1057 	if (cancel_delayed_work_sync(&priv->scan_check)) {
1058 		mutex_lock(&priv->mutex);
1059 		iwl_force_scan_end(priv);
1060 		mutex_unlock(&priv->mutex);
1061 	}
1062 }
1063