xref: /linux/drivers/net/wireless/intel/iwlwifi/dvm/scan.c (revision 0d3b051adbb72ed81956447d0d1e54d5943ee6f5)
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  * Contact Information:
8  *  Intel Linux Wireless <linuxwifi@intel.com>
9  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
10  *****************************************************************************/
11 #include <linux/slab.h>
12 #include <linux/types.h>
13 #include <linux/etherdevice.h>
14 #include <net/mac80211.h>
15 
16 #include "dev.h"
17 #include "agn.h"
18 
19 /* For active scan, listen ACTIVE_DWELL_TIME (msec) on each channel after
20  * sending probe req.  This should be set long enough to hear probe responses
21  * from more than one AP.  */
22 #define IWL_ACTIVE_DWELL_TIME_24    (30)       /* all times in msec */
23 #define IWL_ACTIVE_DWELL_TIME_52    (20)
24 
25 #define IWL_ACTIVE_DWELL_FACTOR_24GHZ (3)
26 #define IWL_ACTIVE_DWELL_FACTOR_52GHZ (2)
27 
28 /* For passive scan, listen PASSIVE_DWELL_TIME (msec) on each channel.
29  * Must be set longer than active dwell time.
30  * For the most reliable scan, set > AP beacon interval (typically 100msec). */
31 #define IWL_PASSIVE_DWELL_TIME_24   (20)       /* all times in msec */
32 #define IWL_PASSIVE_DWELL_TIME_52   (10)
33 #define IWL_PASSIVE_DWELL_BASE      (100)
34 #define IWL_CHANNEL_TUNE_TIME       5
35 #define MAX_SCAN_CHANNEL	    50
36 
37 /* For reset radio, need minimal dwell time only */
38 #define IWL_RADIO_RESET_DWELL_TIME	5
39 
40 static int iwl_send_scan_abort(struct iwl_priv *priv)
41 {
42 	int ret;
43 	struct iwl_host_cmd cmd = {
44 		.id = REPLY_SCAN_ABORT_CMD,
45 		.flags = CMD_WANT_SKB,
46 	};
47 	__le32 *status;
48 
49 	/* Exit instantly with error when device is not ready
50 	 * to receive scan abort command or it does not perform
51 	 * hardware scan currently */
52 	if (!test_bit(STATUS_READY, &priv->status) ||
53 	    !test_bit(STATUS_SCAN_HW, &priv->status) ||
54 	    test_bit(STATUS_FW_ERROR, &priv->status))
55 		return -EIO;
56 
57 	ret = iwl_dvm_send_cmd(priv, &cmd);
58 	if (ret)
59 		return ret;
60 
61 	status = (void *)cmd.resp_pkt->data;
62 	if (*status != CAN_ABORT_STATUS) {
63 		/* The scan abort will return 1 for success or
64 		 * 2 for "failure".  A failure condition can be
65 		 * due to simply not being in an active scan which
66 		 * can occur if we send the scan abort before we
67 		 * the microcode has notified us that a scan is
68 		 * completed. */
69 		IWL_DEBUG_SCAN(priv, "SCAN_ABORT ret %d.\n",
70 			       le32_to_cpu(*status));
71 		ret = -EIO;
72 	}
73 
74 	iwl_free_resp(&cmd);
75 	return ret;
76 }
77 
78 static void iwl_complete_scan(struct iwl_priv *priv, bool aborted)
79 {
80 	struct cfg80211_scan_info info = {
81 		.aborted = aborted,
82 	};
83 
84 	/* check if scan was requested from mac80211 */
85 	if (priv->scan_request) {
86 		IWL_DEBUG_SCAN(priv, "Complete scan in mac80211\n");
87 		ieee80211_scan_completed(priv->hw, &info);
88 	}
89 
90 	priv->scan_type = IWL_SCAN_NORMAL;
91 	priv->scan_vif = NULL;
92 	priv->scan_request = NULL;
93 }
94 
95 static void iwl_process_scan_complete(struct iwl_priv *priv)
96 {
97 	bool aborted;
98 
99 	lockdep_assert_held(&priv->mutex);
100 
101 	if (!test_and_clear_bit(STATUS_SCAN_COMPLETE, &priv->status))
102 		return;
103 
104 	IWL_DEBUG_SCAN(priv, "Completed scan.\n");
105 
106 	cancel_delayed_work(&priv->scan_check);
107 
108 	aborted = test_and_clear_bit(STATUS_SCAN_ABORTING, &priv->status);
109 	if (aborted)
110 		IWL_DEBUG_SCAN(priv, "Aborted scan completed.\n");
111 
112 	if (!test_and_clear_bit(STATUS_SCANNING, &priv->status)) {
113 		IWL_DEBUG_SCAN(priv, "Scan already completed.\n");
114 		goto out_settings;
115 	}
116 
117 	if (priv->scan_type != IWL_SCAN_NORMAL && !aborted) {
118 		int err;
119 
120 		/* Check if mac80211 requested scan during our internal scan */
121 		if (priv->scan_request == NULL)
122 			goto out_complete;
123 
124 		/* If so request a new scan */
125 		err = iwl_scan_initiate(priv, priv->scan_vif, IWL_SCAN_NORMAL,
126 					priv->scan_request->channels[0]->band);
127 		if (err) {
128 			IWL_DEBUG_SCAN(priv,
129 				"failed to initiate pending scan: %d\n", err);
130 			aborted = true;
131 			goto out_complete;
132 		}
133 
134 		return;
135 	}
136 
137 out_complete:
138 	iwl_complete_scan(priv, aborted);
139 
140 out_settings:
141 	/* Can we still talk to firmware ? */
142 	if (!iwl_is_ready_rf(priv))
143 		return;
144 
145 	iwlagn_post_scan(priv);
146 }
147 
148 void iwl_force_scan_end(struct iwl_priv *priv)
149 {
150 	lockdep_assert_held(&priv->mutex);
151 
152 	if (!test_bit(STATUS_SCANNING, &priv->status)) {
153 		IWL_DEBUG_SCAN(priv, "Forcing scan end while not scanning\n");
154 		return;
155 	}
156 
157 	IWL_DEBUG_SCAN(priv, "Forcing scan end\n");
158 	clear_bit(STATUS_SCANNING, &priv->status);
159 	clear_bit(STATUS_SCAN_HW, &priv->status);
160 	clear_bit(STATUS_SCAN_ABORTING, &priv->status);
161 	clear_bit(STATUS_SCAN_COMPLETE, &priv->status);
162 	iwl_complete_scan(priv, true);
163 }
164 
165 static void iwl_do_scan_abort(struct iwl_priv *priv)
166 {
167 	int ret;
168 
169 	lockdep_assert_held(&priv->mutex);
170 
171 	if (!test_bit(STATUS_SCANNING, &priv->status)) {
172 		IWL_DEBUG_SCAN(priv, "Not performing scan to abort\n");
173 		return;
174 	}
175 
176 	if (test_and_set_bit(STATUS_SCAN_ABORTING, &priv->status)) {
177 		IWL_DEBUG_SCAN(priv, "Scan abort in progress\n");
178 		return;
179 	}
180 
181 	ret = iwl_send_scan_abort(priv);
182 	if (ret) {
183 		IWL_DEBUG_SCAN(priv, "Send scan abort failed %d\n", ret);
184 		iwl_force_scan_end(priv);
185 	} else
186 		IWL_DEBUG_SCAN(priv, "Successfully send scan abort\n");
187 }
188 
189 /*
190  * iwl_scan_cancel - Cancel any currently executing HW scan
191  */
192 int iwl_scan_cancel(struct iwl_priv *priv)
193 {
194 	IWL_DEBUG_SCAN(priv, "Queuing abort scan\n");
195 	queue_work(priv->workqueue, &priv->abort_scan);
196 	return 0;
197 }
198 
199 /*
200  * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
201  * @ms: amount of time to wait (in milliseconds) for scan to abort
202  */
203 void iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
204 {
205 	unsigned long timeout = jiffies + msecs_to_jiffies(ms);
206 
207 	lockdep_assert_held(&priv->mutex);
208 
209 	IWL_DEBUG_SCAN(priv, "Scan cancel timeout\n");
210 
211 	iwl_do_scan_abort(priv);
212 
213 	while (time_before_eq(jiffies, timeout)) {
214 		if (!test_bit(STATUS_SCAN_HW, &priv->status))
215 			goto finished;
216 		msleep(20);
217 	}
218 
219 	return;
220 
221  finished:
222 	/*
223 	 * Now STATUS_SCAN_HW is clear. This means that the
224 	 * device finished, but the background work is going
225 	 * to execute at best as soon as we release the mutex.
226 	 * Since we need to be able to issue a new scan right
227 	 * after this function returns, run the complete here.
228 	 * The STATUS_SCAN_COMPLETE bit will then be cleared
229 	 * and prevent the background work from "completing"
230 	 * a possible new scan.
231 	 */
232 	iwl_process_scan_complete(priv);
233 }
234 
235 /* Service response to REPLY_SCAN_CMD (0x80) */
236 static void iwl_rx_reply_scan(struct iwl_priv *priv,
237 			      struct iwl_rx_cmd_buffer *rxb)
238 {
239 #ifdef CONFIG_IWLWIFI_DEBUG
240 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
241 	struct iwl_scanreq_notification *notif = (void *)pkt->data;
242 
243 	IWL_DEBUG_SCAN(priv, "Scan request status = 0x%x\n", notif->status);
244 #endif
245 }
246 
247 /* Service SCAN_START_NOTIFICATION (0x82) */
248 static void iwl_rx_scan_start_notif(struct iwl_priv *priv,
249 				    struct iwl_rx_cmd_buffer *rxb)
250 {
251 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
252 	struct iwl_scanstart_notification *notif = (void *)pkt->data;
253 
254 	priv->scan_start_tsf = le32_to_cpu(notif->tsf_low);
255 	IWL_DEBUG_SCAN(priv, "Scan start: "
256 		       "%d [802.11%s] "
257 		       "(TSF: 0x%08X:%08X) - %d (beacon timer %u)\n",
258 		       notif->channel,
259 		       notif->band ? "bg" : "a",
260 		       le32_to_cpu(notif->tsf_high),
261 		       le32_to_cpu(notif->tsf_low),
262 		       notif->status, notif->beacon_timer);
263 }
264 
265 /* Service SCAN_RESULTS_NOTIFICATION (0x83) */
266 static void iwl_rx_scan_results_notif(struct iwl_priv *priv,
267 				      struct iwl_rx_cmd_buffer *rxb)
268 {
269 #ifdef CONFIG_IWLWIFI_DEBUG
270 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
271 	struct iwl_scanresults_notification *notif = (void *)pkt->data;
272 
273 	IWL_DEBUG_SCAN(priv, "Scan ch.res: "
274 		       "%d [802.11%s] "
275 		       "probe status: %u:%u "
276 		       "(TSF: 0x%08X:%08X) - %d "
277 		       "elapsed=%lu usec\n",
278 		       notif->channel,
279 		       notif->band ? "bg" : "a",
280 		       notif->probe_status, notif->num_probe_not_sent,
281 		       le32_to_cpu(notif->tsf_high),
282 		       le32_to_cpu(notif->tsf_low),
283 		       le32_to_cpu(notif->statistics[0]),
284 		       le32_to_cpu(notif->tsf_low) - priv->scan_start_tsf);
285 #endif
286 }
287 
288 /* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
289 static void iwl_rx_scan_complete_notif(struct iwl_priv *priv,
290 				       struct iwl_rx_cmd_buffer *rxb)
291 {
292 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
293 	struct iwl_scancomplete_notification *scan_notif = (void *)pkt->data;
294 
295 	IWL_DEBUG_SCAN(priv, "Scan complete: %d channels (TSF 0x%08X:%08X) - %d\n",
296 		       scan_notif->scanned_channels,
297 		       scan_notif->tsf_low,
298 		       scan_notif->tsf_high, scan_notif->status);
299 
300 	IWL_DEBUG_SCAN(priv, "Scan on %sGHz took %dms\n",
301 		       (priv->scan_band == NL80211_BAND_2GHZ) ? "2.4" : "5.2",
302 		       jiffies_to_msecs(jiffies - priv->scan_start));
303 
304 	/*
305 	 * When aborting, we run the scan completed background work inline
306 	 * and the background work must then do nothing. The SCAN_COMPLETE
307 	 * bit helps implement that logic and thus needs to be set before
308 	 * queueing the work. Also, since the scan abort waits for SCAN_HW
309 	 * to clear, we need to set SCAN_COMPLETE before clearing SCAN_HW
310 	 * to avoid a race there.
311 	 */
312 	set_bit(STATUS_SCAN_COMPLETE, &priv->status);
313 	clear_bit(STATUS_SCAN_HW, &priv->status);
314 	queue_work(priv->workqueue, &priv->scan_completed);
315 
316 	if (priv->iw_mode != NL80211_IFTYPE_ADHOC &&
317 	    iwl_advanced_bt_coexist(priv) &&
318 	    priv->bt_status != scan_notif->bt_status) {
319 		if (scan_notif->bt_status) {
320 			/* BT on */
321 			if (!priv->bt_ch_announce)
322 				priv->bt_traffic_load =
323 					IWL_BT_COEX_TRAFFIC_LOAD_HIGH;
324 			/*
325 			 * otherwise, no traffic load information provided
326 			 * no changes made
327 			 */
328 		} else {
329 			/* BT off */
330 			priv->bt_traffic_load =
331 				IWL_BT_COEX_TRAFFIC_LOAD_NONE;
332 		}
333 		priv->bt_status = scan_notif->bt_status;
334 		queue_work(priv->workqueue,
335 			   &priv->bt_traffic_change_work);
336 	}
337 }
338 
339 void iwl_setup_rx_scan_handlers(struct iwl_priv *priv)
340 {
341 	/* scan handlers */
342 	priv->rx_handlers[REPLY_SCAN_CMD] = iwl_rx_reply_scan;
343 	priv->rx_handlers[SCAN_START_NOTIFICATION] = iwl_rx_scan_start_notif;
344 	priv->rx_handlers[SCAN_RESULTS_NOTIFICATION] =
345 					iwl_rx_scan_results_notif;
346 	priv->rx_handlers[SCAN_COMPLETE_NOTIFICATION] =
347 					iwl_rx_scan_complete_notif;
348 }
349 
350 static u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
351 				     enum nl80211_band band, u8 n_probes)
352 {
353 	if (band == NL80211_BAND_5GHZ)
354 		return IWL_ACTIVE_DWELL_TIME_52 +
355 			IWL_ACTIVE_DWELL_FACTOR_52GHZ * (n_probes + 1);
356 	else
357 		return IWL_ACTIVE_DWELL_TIME_24 +
358 			IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
359 }
360 
361 static u16 iwl_limit_dwell(struct iwl_priv *priv, u16 dwell_time)
362 {
363 	struct iwl_rxon_context *ctx;
364 	int limits[NUM_IWL_RXON_CTX] = {};
365 	int n_active = 0;
366 	u16 limit;
367 
368 	BUILD_BUG_ON(NUM_IWL_RXON_CTX != 2);
369 
370 	/*
371 	 * If we're associated, we clamp the dwell time 98%
372 	 * of the beacon interval (minus 2 * channel tune time)
373 	 * If both contexts are active, we have to restrict to
374 	 * 1/2 of the minimum of them, because they might be in
375 	 * lock-step with the time inbetween only half of what
376 	 * time we'd have in each of them.
377 	 */
378 	for_each_context(priv, ctx) {
379 		switch (ctx->staging.dev_type) {
380 		case RXON_DEV_TYPE_P2P:
381 			/* no timing constraints */
382 			continue;
383 		case RXON_DEV_TYPE_ESS:
384 		default:
385 			/* timing constraints if associated */
386 			if (!iwl_is_associated_ctx(ctx))
387 				continue;
388 			break;
389 		case RXON_DEV_TYPE_CP:
390 		case RXON_DEV_TYPE_2STA:
391 			/*
392 			 * These seem to always have timers for TBTT
393 			 * active in uCode even when not associated yet.
394 			 */
395 			break;
396 		}
397 
398 		limits[n_active++] = ctx->beacon_int ?: IWL_PASSIVE_DWELL_BASE;
399 	}
400 
401 	switch (n_active) {
402 	case 0:
403 		return dwell_time;
404 	case 2:
405 		limit = (limits[1] * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
406 		limit /= 2;
407 		dwell_time = min(limit, dwell_time);
408 		fallthrough;
409 	case 1:
410 		limit = (limits[0] * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
411 		limit /= n_active;
412 		return min(limit, dwell_time);
413 	default:
414 		WARN_ON_ONCE(1);
415 		return dwell_time;
416 	}
417 }
418 
419 static u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
420 				      enum nl80211_band band)
421 {
422 	u16 passive = (band == NL80211_BAND_2GHZ) ?
423 	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
424 	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;
425 
426 	return iwl_limit_dwell(priv, passive);
427 }
428 
429 /* Return valid, unused, channel for a passive scan to reset the RF */
430 static u8 iwl_get_single_channel_number(struct iwl_priv *priv,
431 					enum nl80211_band band)
432 {
433 	struct ieee80211_supported_band *sband = priv->hw->wiphy->bands[band];
434 	struct iwl_rxon_context *ctx;
435 	int i;
436 
437 	for (i = 0; i < sband->n_channels; i++) {
438 		bool busy = false;
439 
440 		for_each_context(priv, ctx) {
441 			busy = sband->channels[i].hw_value ==
442 				le16_to_cpu(ctx->staging.channel);
443 			if (busy)
444 				break;
445 		}
446 
447 		if (busy)
448 			continue;
449 
450 		if (!(sband->channels[i].flags & IEEE80211_CHAN_DISABLED))
451 			return sband->channels[i].hw_value;
452 	}
453 
454 	return 0;
455 }
456 
457 static int iwl_get_channel_for_reset_scan(struct iwl_priv *priv,
458 					  struct ieee80211_vif *vif,
459 					  enum nl80211_band band,
460 					  struct iwl_scan_channel *scan_ch)
461 {
462 	const struct ieee80211_supported_band *sband;
463 	u16 channel;
464 
465 	sband = iwl_get_hw_mode(priv, band);
466 	if (!sband) {
467 		IWL_ERR(priv, "invalid band\n");
468 		return 0;
469 	}
470 
471 	channel = iwl_get_single_channel_number(priv, band);
472 	if (channel) {
473 		scan_ch->channel = cpu_to_le16(channel);
474 		scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
475 		scan_ch->active_dwell =
476 			cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
477 		scan_ch->passive_dwell =
478 			cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
479 		/* Set txpower levels to defaults */
480 		scan_ch->dsp_atten = 110;
481 		if (band == NL80211_BAND_5GHZ)
482 			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
483 		else
484 			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
485 		return 1;
486 	}
487 
488 	IWL_ERR(priv, "no valid channel found\n");
489 	return 0;
490 }
491 
492 static int iwl_get_channels_for_scan(struct iwl_priv *priv,
493 				     struct ieee80211_vif *vif,
494 				     enum nl80211_band band,
495 				     u8 is_active, u8 n_probes,
496 				     struct iwl_scan_channel *scan_ch)
497 {
498 	struct ieee80211_channel *chan;
499 	const struct ieee80211_supported_band *sband;
500 	u16 passive_dwell = 0;
501 	u16 active_dwell = 0;
502 	int added, i;
503 	u16 channel;
504 
505 	sband = iwl_get_hw_mode(priv, band);
506 	if (!sband)
507 		return 0;
508 
509 	active_dwell = iwl_get_active_dwell_time(priv, band, n_probes);
510 	passive_dwell = iwl_get_passive_dwell_time(priv, band);
511 
512 	if (passive_dwell <= active_dwell)
513 		passive_dwell = active_dwell + 1;
514 
515 	for (i = 0, added = 0; i < priv->scan_request->n_channels; i++) {
516 		chan = priv->scan_request->channels[i];
517 
518 		if (chan->band != band)
519 			continue;
520 
521 		channel = chan->hw_value;
522 		scan_ch->channel = cpu_to_le16(channel);
523 
524 		if (!is_active || (chan->flags & IEEE80211_CHAN_NO_IR))
525 			scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
526 		else
527 			scan_ch->type = SCAN_CHANNEL_TYPE_ACTIVE;
528 
529 		if (n_probes)
530 			scan_ch->type |= IWL_SCAN_PROBE_MASK(n_probes);
531 
532 		scan_ch->active_dwell = cpu_to_le16(active_dwell);
533 		scan_ch->passive_dwell = cpu_to_le16(passive_dwell);
534 
535 		/* Set txpower levels to defaults */
536 		scan_ch->dsp_atten = 110;
537 
538 		/* NOTE: if we were doing 6Mb OFDM for scans we'd use
539 		 * power level:
540 		 * scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
541 		 */
542 		if (band == NL80211_BAND_5GHZ)
543 			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
544 		else
545 			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
546 
547 		IWL_DEBUG_SCAN(priv, "Scanning ch=%d prob=0x%X [%s %d]\n",
548 			       channel, le32_to_cpu(scan_ch->type),
549 			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
550 				"ACTIVE" : "PASSIVE",
551 			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
552 			       active_dwell : passive_dwell);
553 
554 		scan_ch++;
555 		added++;
556 	}
557 
558 	IWL_DEBUG_SCAN(priv, "total channels to scan %d\n", added);
559 	return added;
560 }
561 
562 /*
563  * iwl_fill_probe_req - fill in all required fields and IE for probe request
564  */
565 static u16 iwl_fill_probe_req(struct ieee80211_mgmt *frame, const u8 *ta,
566 			      const u8 *ies, int ie_len, const u8 *ssid,
567 			      u8 ssid_len, int left)
568 {
569 	int len = 0;
570 	u8 *pos = NULL;
571 
572 	/* Make sure there is enough space for the probe request,
573 	 * two mandatory IEs and the data */
574 	left -= 24;
575 	if (left < 0)
576 		return 0;
577 
578 	frame->frame_control = cpu_to_le16(IEEE80211_STYPE_PROBE_REQ);
579 	eth_broadcast_addr(frame->da);
580 	memcpy(frame->sa, ta, ETH_ALEN);
581 	eth_broadcast_addr(frame->bssid);
582 	frame->seq_ctrl = 0;
583 
584 	len += 24;
585 
586 	/* ...next IE... */
587 	pos = &frame->u.probe_req.variable[0];
588 
589 	/* fill in our SSID IE */
590 	left -= ssid_len + 2;
591 	if (left < 0)
592 		return 0;
593 	*pos++ = WLAN_EID_SSID;
594 	*pos++ = ssid_len;
595 	if (ssid && ssid_len) {
596 		memcpy(pos, ssid, ssid_len);
597 		pos += ssid_len;
598 	}
599 
600 	len += ssid_len + 2;
601 
602 	if (WARN_ON(left < ie_len))
603 		return len;
604 
605 	if (ies && ie_len) {
606 		memcpy(pos, ies, ie_len);
607 		len += ie_len;
608 	}
609 
610 	return (u16)len;
611 }
612 
613 static int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
614 {
615 	struct iwl_host_cmd cmd = {
616 		.id = REPLY_SCAN_CMD,
617 		.len = { sizeof(struct iwl_scan_cmd), },
618 	};
619 	struct iwl_scan_cmd *scan;
620 	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
621 	u32 rate_flags = 0;
622 	u16 cmd_len = 0;
623 	u16 rx_chain = 0;
624 	enum nl80211_band band;
625 	u8 n_probes = 0;
626 	u8 rx_ant = priv->nvm_data->valid_rx_ant;
627 	u8 rate;
628 	bool is_active = false;
629 	int  chan_mod;
630 	u8 active_chains;
631 	u8 scan_tx_antennas = priv->nvm_data->valid_tx_ant;
632 	int ret;
633 	int scan_cmd_size = sizeof(struct iwl_scan_cmd) +
634 			    MAX_SCAN_CHANNEL * sizeof(struct iwl_scan_channel) +
635 			    priv->fw->ucode_capa.max_probe_length;
636 	const u8 *ssid = NULL;
637 	u8 ssid_len = 0;
638 
639 	if (WARN_ON(priv->scan_type == IWL_SCAN_NORMAL &&
640 		    (!priv->scan_request ||
641 		     priv->scan_request->n_channels > MAX_SCAN_CHANNEL)))
642 		return -EINVAL;
643 
644 	lockdep_assert_held(&priv->mutex);
645 
646 	if (vif)
647 		ctx = iwl_rxon_ctx_from_vif(vif);
648 
649 	if (!priv->scan_cmd) {
650 		priv->scan_cmd = kmalloc(scan_cmd_size, GFP_KERNEL);
651 		if (!priv->scan_cmd) {
652 			IWL_DEBUG_SCAN(priv,
653 				       "fail to allocate memory for scan\n");
654 			return -ENOMEM;
655 		}
656 	}
657 	scan = priv->scan_cmd;
658 	memset(scan, 0, scan_cmd_size);
659 
660 	scan->quiet_plcp_th = IWL_PLCP_QUIET_THRESH;
661 	scan->quiet_time = IWL_ACTIVE_QUIET_TIME;
662 
663 	if (iwl_is_any_associated(priv)) {
664 		u16 interval = 0;
665 		u32 extra;
666 		u32 suspend_time = 100;
667 		u32 scan_suspend_time = 100;
668 
669 		IWL_DEBUG_INFO(priv, "Scanning while associated...\n");
670 		switch (priv->scan_type) {
671 		case IWL_SCAN_RADIO_RESET:
672 			interval = 0;
673 			break;
674 		case IWL_SCAN_NORMAL:
675 			interval = vif->bss_conf.beacon_int;
676 			break;
677 		}
678 
679 		scan->suspend_time = 0;
680 		scan->max_out_time = cpu_to_le32(200 * 1024);
681 		if (!interval)
682 			interval = suspend_time;
683 
684 		extra = (suspend_time / interval) << 22;
685 		scan_suspend_time = (extra |
686 		    ((suspend_time % interval) * 1024));
687 		scan->suspend_time = cpu_to_le32(scan_suspend_time);
688 		IWL_DEBUG_SCAN(priv, "suspend_time 0x%X beacon interval %d\n",
689 			       scan_suspend_time, interval);
690 	}
691 
692 	switch (priv->scan_type) {
693 	case IWL_SCAN_RADIO_RESET:
694 		IWL_DEBUG_SCAN(priv, "Start internal passive scan.\n");
695 		/*
696 		 * Override quiet time as firmware checks that active
697 		 * dwell is >= quiet; since we use passive scan it'll
698 		 * not actually be used.
699 		 */
700 		scan->quiet_time = cpu_to_le16(IWL_RADIO_RESET_DWELL_TIME);
701 		break;
702 	case IWL_SCAN_NORMAL:
703 		if (priv->scan_request->n_ssids) {
704 			int i, p = 0;
705 			IWL_DEBUG_SCAN(priv, "Kicking off active scan\n");
706 			/*
707 			 * The highest priority SSID is inserted to the
708 			 * probe request template.
709 			 */
710 			ssid_len = priv->scan_request->ssids[0].ssid_len;
711 			ssid = priv->scan_request->ssids[0].ssid;
712 
713 			/*
714 			 * Invert the order of ssids, the firmware will invert
715 			 * it back.
716 			 */
717 			for (i = priv->scan_request->n_ssids - 1; i >= 1; i--) {
718 				scan->direct_scan[p].id = WLAN_EID_SSID;
719 				scan->direct_scan[p].len =
720 					priv->scan_request->ssids[i].ssid_len;
721 				memcpy(scan->direct_scan[p].ssid,
722 				       priv->scan_request->ssids[i].ssid,
723 				       priv->scan_request->ssids[i].ssid_len);
724 				n_probes++;
725 				p++;
726 			}
727 			is_active = true;
728 		} else
729 			IWL_DEBUG_SCAN(priv, "Start passive scan.\n");
730 		break;
731 	}
732 
733 	scan->tx_cmd.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK;
734 	scan->tx_cmd.sta_id = ctx->bcast_sta_id;
735 	scan->tx_cmd.stop_time.life_time = TX_CMD_LIFE_TIME_INFINITE;
736 
737 	switch (priv->scan_band) {
738 	case NL80211_BAND_2GHZ:
739 		scan->flags = RXON_FLG_BAND_24G_MSK | RXON_FLG_AUTO_DETECT_MSK;
740 		chan_mod = le32_to_cpu(
741 			priv->contexts[IWL_RXON_CTX_BSS].active.flags &
742 						RXON_FLG_CHANNEL_MODE_MSK)
743 				       >> RXON_FLG_CHANNEL_MODE_POS;
744 		if ((priv->scan_request && priv->scan_request->no_cck) ||
745 		    chan_mod == CHANNEL_MODE_PURE_40) {
746 			rate = IWL_RATE_6M_PLCP;
747 		} else {
748 			rate = IWL_RATE_1M_PLCP;
749 			rate_flags = RATE_MCS_CCK_MSK;
750 		}
751 		/*
752 		 * Internal scans are passive, so we can indiscriminately set
753 		 * the BT ignore flag on 2.4 GHz since it applies to TX only.
754 		 */
755 		if (priv->lib->bt_params &&
756 		    priv->lib->bt_params->advanced_bt_coexist)
757 			scan->tx_cmd.tx_flags |= TX_CMD_FLG_IGNORE_BT;
758 		break;
759 	case NL80211_BAND_5GHZ:
760 		rate = IWL_RATE_6M_PLCP;
761 		break;
762 	default:
763 		IWL_WARN(priv, "Invalid scan band\n");
764 		return -EIO;
765 	}
766 
767 	/*
768 	 * If active scanning is requested but a certain channel is
769 	 * marked passive, we can do active scanning if we detect
770 	 * transmissions.
771 	 *
772 	 * There is an issue with some firmware versions that triggers
773 	 * a sysassert on a "good CRC threshold" of zero (== disabled),
774 	 * on a radar channel even though this means that we should NOT
775 	 * send probes.
776 	 *
777 	 * The "good CRC threshold" is the number of frames that we
778 	 * need to receive during our dwell time on a channel before
779 	 * sending out probes -- setting this to a huge value will
780 	 * mean we never reach it, but at the same time work around
781 	 * the aforementioned issue. Thus use IWL_GOOD_CRC_TH_NEVER
782 	 * here instead of IWL_GOOD_CRC_TH_DISABLED.
783 	 *
784 	 * This was fixed in later versions along with some other
785 	 * scan changes, and the threshold behaves as a flag in those
786 	 * versions.
787 	 */
788 	if (priv->new_scan_threshold_behaviour)
789 		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
790 						IWL_GOOD_CRC_TH_DISABLED;
791 	else
792 		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
793 						IWL_GOOD_CRC_TH_NEVER;
794 
795 	band = priv->scan_band;
796 
797 	if (band == NL80211_BAND_2GHZ &&
798 	    priv->lib->bt_params &&
799 	    priv->lib->bt_params->advanced_bt_coexist) {
800 		/* transmit 2.4 GHz probes only on first antenna */
801 		scan_tx_antennas = first_antenna(scan_tx_antennas);
802 	}
803 
804 	priv->scan_tx_ant[band] = iwl_toggle_tx_ant(priv,
805 						    priv->scan_tx_ant[band],
806 						    scan_tx_antennas);
807 	rate_flags |= iwl_ant_idx_to_flags(priv->scan_tx_ant[band]);
808 	scan->tx_cmd.rate_n_flags = iwl_hw_set_rate_n_flags(rate, rate_flags);
809 
810 	/*
811 	 * In power save mode while associated use one chain,
812 	 * otherwise use all chains
813 	 */
814 	if (test_bit(STATUS_POWER_PMI, &priv->status) &&
815 	    !(priv->hw->conf.flags & IEEE80211_CONF_IDLE)) {
816 		/* rx_ant has been set to all valid chains previously */
817 		active_chains = rx_ant &
818 				((u8)(priv->chain_noise_data.active_chains));
819 		if (!active_chains)
820 			active_chains = rx_ant;
821 
822 		IWL_DEBUG_SCAN(priv, "chain_noise_data.active_chains: %u\n",
823 				priv->chain_noise_data.active_chains);
824 
825 		rx_ant = first_antenna(active_chains);
826 	}
827 	if (priv->lib->bt_params &&
828 	    priv->lib->bt_params->advanced_bt_coexist &&
829 	    priv->bt_full_concurrent) {
830 		/* operated as 1x1 in full concurrency mode */
831 		rx_ant = first_antenna(rx_ant);
832 	}
833 
834 	/* MIMO is not used here, but value is required */
835 	rx_chain |=
836 		priv->nvm_data->valid_rx_ant << RXON_RX_CHAIN_VALID_POS;
837 	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_MIMO_SEL_POS;
838 	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_SEL_POS;
839 	rx_chain |= 0x1 << RXON_RX_CHAIN_DRIVER_FORCE_POS;
840 	scan->rx_chain = cpu_to_le16(rx_chain);
841 	switch (priv->scan_type) {
842 	case IWL_SCAN_NORMAL:
843 		cmd_len = iwl_fill_probe_req(
844 					(struct ieee80211_mgmt *)scan->data,
845 					vif->addr,
846 					priv->scan_request->ie,
847 					priv->scan_request->ie_len,
848 					ssid, ssid_len,
849 					scan_cmd_size - sizeof(*scan));
850 		break;
851 	case IWL_SCAN_RADIO_RESET:
852 		/* use bcast addr, will not be transmitted but must be valid */
853 		cmd_len = iwl_fill_probe_req(
854 					(struct ieee80211_mgmt *)scan->data,
855 					iwl_bcast_addr, NULL, 0,
856 					NULL, 0,
857 					scan_cmd_size - sizeof(*scan));
858 		break;
859 	default:
860 		BUG();
861 	}
862 	scan->tx_cmd.len = cpu_to_le16(cmd_len);
863 
864 	scan->filter_flags |= (RXON_FILTER_ACCEPT_GRP_MSK |
865 			       RXON_FILTER_BCON_AWARE_MSK);
866 
867 	switch (priv->scan_type) {
868 	case IWL_SCAN_RADIO_RESET:
869 		scan->channel_count =
870 			iwl_get_channel_for_reset_scan(priv, vif, band,
871 				(void *)&scan->data[cmd_len]);
872 		break;
873 	case IWL_SCAN_NORMAL:
874 		scan->channel_count =
875 			iwl_get_channels_for_scan(priv, vif, band,
876 				is_active, n_probes,
877 				(void *)&scan->data[cmd_len]);
878 		break;
879 	}
880 
881 	if (scan->channel_count == 0) {
882 		IWL_DEBUG_SCAN(priv, "channel count %d\n", scan->channel_count);
883 		return -EIO;
884 	}
885 
886 	cmd.len[0] += le16_to_cpu(scan->tx_cmd.len) +
887 	    scan->channel_count * sizeof(struct iwl_scan_channel);
888 	cmd.data[0] = scan;
889 	cmd.dataflags[0] = IWL_HCMD_DFL_NOCOPY;
890 	scan->len = cpu_to_le16(cmd.len[0]);
891 
892 	/* set scan bit here for PAN params */
893 	set_bit(STATUS_SCAN_HW, &priv->status);
894 
895 	ret = iwlagn_set_pan_params(priv);
896 	if (ret) {
897 		clear_bit(STATUS_SCAN_HW, &priv->status);
898 		return ret;
899 	}
900 
901 	ret = iwl_dvm_send_cmd(priv, &cmd);
902 	if (ret) {
903 		clear_bit(STATUS_SCAN_HW, &priv->status);
904 		iwlagn_set_pan_params(priv);
905 	}
906 
907 	return ret;
908 }
909 
910 void iwl_init_scan_params(struct iwl_priv *priv)
911 {
912 	u8 ant_idx = fls(priv->nvm_data->valid_tx_ant) - 1;
913 	if (!priv->scan_tx_ant[NL80211_BAND_5GHZ])
914 		priv->scan_tx_ant[NL80211_BAND_5GHZ] = ant_idx;
915 	if (!priv->scan_tx_ant[NL80211_BAND_2GHZ])
916 		priv->scan_tx_ant[NL80211_BAND_2GHZ] = ant_idx;
917 }
918 
919 int __must_check iwl_scan_initiate(struct iwl_priv *priv,
920 				   struct ieee80211_vif *vif,
921 				   enum iwl_scan_type scan_type,
922 				   enum nl80211_band band)
923 {
924 	int ret;
925 
926 	lockdep_assert_held(&priv->mutex);
927 
928 	cancel_delayed_work(&priv->scan_check);
929 
930 	if (!iwl_is_ready_rf(priv)) {
931 		IWL_WARN(priv, "Request scan called when driver not ready.\n");
932 		return -EIO;
933 	}
934 
935 	if (test_bit(STATUS_SCAN_HW, &priv->status)) {
936 		IWL_DEBUG_SCAN(priv,
937 			"Multiple concurrent scan requests in parallel.\n");
938 		return -EBUSY;
939 	}
940 
941 	if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
942 		IWL_DEBUG_SCAN(priv, "Scan request while abort pending.\n");
943 		return -EBUSY;
944 	}
945 
946 	IWL_DEBUG_SCAN(priv, "Starting %sscan...\n",
947 			scan_type == IWL_SCAN_NORMAL ? "" :
948 			"internal short ");
949 
950 	set_bit(STATUS_SCANNING, &priv->status);
951 	priv->scan_type = scan_type;
952 	priv->scan_start = jiffies;
953 	priv->scan_band = band;
954 
955 	ret = iwlagn_request_scan(priv, vif);
956 	if (ret) {
957 		clear_bit(STATUS_SCANNING, &priv->status);
958 		priv->scan_type = IWL_SCAN_NORMAL;
959 		return ret;
960 	}
961 
962 	queue_delayed_work(priv->workqueue, &priv->scan_check,
963 			   IWL_SCAN_CHECK_WATCHDOG);
964 
965 	return 0;
966 }
967 
968 
969 /*
970  * internal short scan, this function should only been called while associated.
971  * It will reset and tune the radio to prevent possible RF related problem
972  */
973 void iwl_internal_short_hw_scan(struct iwl_priv *priv)
974 {
975 	queue_work(priv->workqueue, &priv->start_internal_scan);
976 }
977 
978 static void iwl_bg_start_internal_scan(struct work_struct *work)
979 {
980 	struct iwl_priv *priv =
981 		container_of(work, struct iwl_priv, start_internal_scan);
982 
983 	IWL_DEBUG_SCAN(priv, "Start internal scan\n");
984 
985 	mutex_lock(&priv->mutex);
986 
987 	if (priv->scan_type == IWL_SCAN_RADIO_RESET) {
988 		IWL_DEBUG_SCAN(priv, "Internal scan already in progress\n");
989 		goto unlock;
990 	}
991 
992 	if (test_bit(STATUS_SCANNING, &priv->status)) {
993 		IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
994 		goto unlock;
995 	}
996 
997 	if (iwl_scan_initiate(priv, NULL, IWL_SCAN_RADIO_RESET, priv->band))
998 		IWL_DEBUG_SCAN(priv, "failed to start internal short scan\n");
999  unlock:
1000 	mutex_unlock(&priv->mutex);
1001 }
1002 
1003 static void iwl_bg_scan_check(struct work_struct *data)
1004 {
1005 	struct iwl_priv *priv =
1006 	    container_of(data, struct iwl_priv, scan_check.work);
1007 
1008 	IWL_DEBUG_SCAN(priv, "Scan check work\n");
1009 
1010 	/* Since we are here firmware does not finish scan and
1011 	 * most likely is in bad shape, so we don't bother to
1012 	 * send abort command, just force scan complete to mac80211 */
1013 	mutex_lock(&priv->mutex);
1014 	iwl_force_scan_end(priv);
1015 	mutex_unlock(&priv->mutex);
1016 }
1017 
1018 static void iwl_bg_abort_scan(struct work_struct *work)
1019 {
1020 	struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);
1021 
1022 	IWL_DEBUG_SCAN(priv, "Abort scan work\n");
1023 
1024 	/* We keep scan_check work queued in case when firmware will not
1025 	 * report back scan completed notification */
1026 	mutex_lock(&priv->mutex);
1027 	iwl_scan_cancel_timeout(priv, 200);
1028 	mutex_unlock(&priv->mutex);
1029 }
1030 
1031 static void iwl_bg_scan_completed(struct work_struct *work)
1032 {
1033 	struct iwl_priv *priv =
1034 		container_of(work, struct iwl_priv, scan_completed);
1035 
1036 	mutex_lock(&priv->mutex);
1037 	iwl_process_scan_complete(priv);
1038 	mutex_unlock(&priv->mutex);
1039 }
1040 
1041 void iwl_setup_scan_deferred_work(struct iwl_priv *priv)
1042 {
1043 	INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed);
1044 	INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
1045 	INIT_WORK(&priv->start_internal_scan, iwl_bg_start_internal_scan);
1046 	INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
1047 }
1048 
1049 void iwl_cancel_scan_deferred_work(struct iwl_priv *priv)
1050 {
1051 	cancel_work_sync(&priv->start_internal_scan);
1052 	cancel_work_sync(&priv->abort_scan);
1053 	cancel_work_sync(&priv->scan_completed);
1054 
1055 	if (cancel_delayed_work_sync(&priv->scan_check)) {
1056 		mutex_lock(&priv->mutex);
1057 		iwl_force_scan_end(priv);
1058 		mutex_unlock(&priv->mutex);
1059 	}
1060 }
1061