xref: /openbmc/linux/net/mac80211/ht.c (revision dea54fba)
1 /*
2  * HT handling
3  *
4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
5  * Copyright 2002-2005, Instant802 Networks, Inc.
6  * Copyright 2005-2006, Devicescape Software, Inc.
7  * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
9  * Copyright 2007-2010, Intel Corporation
10  * Copyright 2017	Intel Deutschland GmbH
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License version 2 as
14  * published by the Free Software Foundation.
15  */
16 
17 #include <linux/ieee80211.h>
18 #include <linux/export.h>
19 #include <net/mac80211.h>
20 #include "ieee80211_i.h"
21 #include "rate.h"
22 
23 static void __check_htcap_disable(struct ieee80211_ht_cap *ht_capa,
24 				  struct ieee80211_ht_cap *ht_capa_mask,
25 				  struct ieee80211_sta_ht_cap *ht_cap,
26 				  u16 flag)
27 {
28 	__le16 le_flag = cpu_to_le16(flag);
29 	if (ht_capa_mask->cap_info & le_flag) {
30 		if (!(ht_capa->cap_info & le_flag))
31 			ht_cap->cap &= ~flag;
32 	}
33 }
34 
35 static void __check_htcap_enable(struct ieee80211_ht_cap *ht_capa,
36 				  struct ieee80211_ht_cap *ht_capa_mask,
37 				  struct ieee80211_sta_ht_cap *ht_cap,
38 				  u16 flag)
39 {
40 	__le16 le_flag = cpu_to_le16(flag);
41 
42 	if ((ht_capa_mask->cap_info & le_flag) &&
43 	    (ht_capa->cap_info & le_flag))
44 		ht_cap->cap |= flag;
45 }
46 
47 void ieee80211_apply_htcap_overrides(struct ieee80211_sub_if_data *sdata,
48 				     struct ieee80211_sta_ht_cap *ht_cap)
49 {
50 	struct ieee80211_ht_cap *ht_capa, *ht_capa_mask;
51 	u8 *scaps, *smask;
52 	int i;
53 
54 	if (!ht_cap->ht_supported)
55 		return;
56 
57 	switch (sdata->vif.type) {
58 	case NL80211_IFTYPE_STATION:
59 		ht_capa = &sdata->u.mgd.ht_capa;
60 		ht_capa_mask = &sdata->u.mgd.ht_capa_mask;
61 		break;
62 	case NL80211_IFTYPE_ADHOC:
63 		ht_capa = &sdata->u.ibss.ht_capa;
64 		ht_capa_mask = &sdata->u.ibss.ht_capa_mask;
65 		break;
66 	default:
67 		WARN_ON_ONCE(1);
68 		return;
69 	}
70 
71 	scaps = (u8 *)(&ht_capa->mcs.rx_mask);
72 	smask = (u8 *)(&ht_capa_mask->mcs.rx_mask);
73 
74 	/* NOTE:  If you add more over-rides here, update register_hw
75 	 * ht_capa_mod_mask logic in main.c as well.
76 	 * And, if this method can ever change ht_cap.ht_supported, fix
77 	 * the check in ieee80211_add_ht_ie.
78 	 */
79 
80 	/* check for HT over-rides, MCS rates first. */
81 	for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++) {
82 		u8 m = smask[i];
83 		ht_cap->mcs.rx_mask[i] &= ~m; /* turn off all masked bits */
84 		/* Add back rates that are supported */
85 		ht_cap->mcs.rx_mask[i] |= (m & scaps[i]);
86 	}
87 
88 	/* Force removal of HT-40 capabilities? */
89 	__check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
90 			      IEEE80211_HT_CAP_SUP_WIDTH_20_40);
91 	__check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
92 			      IEEE80211_HT_CAP_SGI_40);
93 
94 	/* Allow user to disable SGI-20 (SGI-40 is handled above) */
95 	__check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
96 			      IEEE80211_HT_CAP_SGI_20);
97 
98 	/* Allow user to disable the max-AMSDU bit. */
99 	__check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
100 			      IEEE80211_HT_CAP_MAX_AMSDU);
101 
102 	/* Allow user to disable LDPC */
103 	__check_htcap_disable(ht_capa, ht_capa_mask, ht_cap,
104 			      IEEE80211_HT_CAP_LDPC_CODING);
105 
106 	/* Allow user to enable 40 MHz intolerant bit. */
107 	__check_htcap_enable(ht_capa, ht_capa_mask, ht_cap,
108 			     IEEE80211_HT_CAP_40MHZ_INTOLERANT);
109 
110 	/* Allow user to decrease AMPDU factor */
111 	if (ht_capa_mask->ampdu_params_info &
112 	    IEEE80211_HT_AMPDU_PARM_FACTOR) {
113 		u8 n = ht_capa->ampdu_params_info &
114 		       IEEE80211_HT_AMPDU_PARM_FACTOR;
115 		if (n < ht_cap->ampdu_factor)
116 			ht_cap->ampdu_factor = n;
117 	}
118 
119 	/* Allow the user to increase AMPDU density. */
120 	if (ht_capa_mask->ampdu_params_info &
121 	    IEEE80211_HT_AMPDU_PARM_DENSITY) {
122 		u8 n = (ht_capa->ampdu_params_info &
123 			IEEE80211_HT_AMPDU_PARM_DENSITY)
124 			>> IEEE80211_HT_AMPDU_PARM_DENSITY_SHIFT;
125 		if (n > ht_cap->ampdu_density)
126 			ht_cap->ampdu_density = n;
127 	}
128 }
129 
130 
131 bool ieee80211_ht_cap_ie_to_sta_ht_cap(struct ieee80211_sub_if_data *sdata,
132 				       struct ieee80211_supported_band *sband,
133 				       const struct ieee80211_ht_cap *ht_cap_ie,
134 				       struct sta_info *sta)
135 {
136 	struct ieee80211_sta_ht_cap ht_cap, own_cap;
137 	u8 ampdu_info, tx_mcs_set_cap;
138 	int i, max_tx_streams;
139 	bool changed;
140 	enum ieee80211_sta_rx_bandwidth bw;
141 	enum ieee80211_smps_mode smps_mode;
142 
143 	memset(&ht_cap, 0, sizeof(ht_cap));
144 
145 	if (!ht_cap_ie || !sband->ht_cap.ht_supported)
146 		goto apply;
147 
148 	ht_cap.ht_supported = true;
149 
150 	own_cap = sband->ht_cap;
151 
152 	/*
153 	 * If user has specified capability over-rides, take care
154 	 * of that if the station we're setting up is the AP or TDLS peer that
155 	 * we advertised a restricted capability set to. Override
156 	 * our own capabilities and then use those below.
157 	 */
158 	if (sdata->vif.type == NL80211_IFTYPE_STATION ||
159 	    sdata->vif.type == NL80211_IFTYPE_ADHOC)
160 		ieee80211_apply_htcap_overrides(sdata, &own_cap);
161 
162 	/*
163 	 * The bits listed in this expression should be
164 	 * the same for the peer and us, if the station
165 	 * advertises more then we can't use those thus
166 	 * we mask them out.
167 	 */
168 	ht_cap.cap = le16_to_cpu(ht_cap_ie->cap_info) &
169 		(own_cap.cap | ~(IEEE80211_HT_CAP_LDPC_CODING |
170 				 IEEE80211_HT_CAP_SUP_WIDTH_20_40 |
171 				 IEEE80211_HT_CAP_GRN_FLD |
172 				 IEEE80211_HT_CAP_SGI_20 |
173 				 IEEE80211_HT_CAP_SGI_40 |
174 				 IEEE80211_HT_CAP_DSSSCCK40));
175 
176 	/*
177 	 * The STBC bits are asymmetric -- if we don't have
178 	 * TX then mask out the peer's RX and vice versa.
179 	 */
180 	if (!(own_cap.cap & IEEE80211_HT_CAP_TX_STBC))
181 		ht_cap.cap &= ~IEEE80211_HT_CAP_RX_STBC;
182 	if (!(own_cap.cap & IEEE80211_HT_CAP_RX_STBC))
183 		ht_cap.cap &= ~IEEE80211_HT_CAP_TX_STBC;
184 
185 	ampdu_info = ht_cap_ie->ampdu_params_info;
186 	ht_cap.ampdu_factor =
187 		ampdu_info & IEEE80211_HT_AMPDU_PARM_FACTOR;
188 	ht_cap.ampdu_density =
189 		(ampdu_info & IEEE80211_HT_AMPDU_PARM_DENSITY) >> 2;
190 
191 	/* own MCS TX capabilities */
192 	tx_mcs_set_cap = own_cap.mcs.tx_params;
193 
194 	/* Copy peer MCS TX capabilities, the driver might need them. */
195 	ht_cap.mcs.tx_params = ht_cap_ie->mcs.tx_params;
196 
197 	/* can we TX with MCS rates? */
198 	if (!(tx_mcs_set_cap & IEEE80211_HT_MCS_TX_DEFINED))
199 		goto apply;
200 
201 	/* Counting from 0, therefore +1 */
202 	if (tx_mcs_set_cap & IEEE80211_HT_MCS_TX_RX_DIFF)
203 		max_tx_streams =
204 			((tx_mcs_set_cap & IEEE80211_HT_MCS_TX_MAX_STREAMS_MASK)
205 				>> IEEE80211_HT_MCS_TX_MAX_STREAMS_SHIFT) + 1;
206 	else
207 		max_tx_streams = IEEE80211_HT_MCS_TX_MAX_STREAMS;
208 
209 	/*
210 	 * 802.11n-2009 20.3.5 / 20.6 says:
211 	 * - indices 0 to 7 and 32 are single spatial stream
212 	 * - 8 to 31 are multiple spatial streams using equal modulation
213 	 *   [8..15 for two streams, 16..23 for three and 24..31 for four]
214 	 * - remainder are multiple spatial streams using unequal modulation
215 	 */
216 	for (i = 0; i < max_tx_streams; i++)
217 		ht_cap.mcs.rx_mask[i] =
218 			own_cap.mcs.rx_mask[i] & ht_cap_ie->mcs.rx_mask[i];
219 
220 	if (tx_mcs_set_cap & IEEE80211_HT_MCS_TX_UNEQUAL_MODULATION)
221 		for (i = IEEE80211_HT_MCS_UNEQUAL_MODULATION_START_BYTE;
222 		     i < IEEE80211_HT_MCS_MASK_LEN; i++)
223 			ht_cap.mcs.rx_mask[i] =
224 				own_cap.mcs.rx_mask[i] &
225 					ht_cap_ie->mcs.rx_mask[i];
226 
227 	/* handle MCS rate 32 too */
228 	if (own_cap.mcs.rx_mask[32/8] & ht_cap_ie->mcs.rx_mask[32/8] & 1)
229 		ht_cap.mcs.rx_mask[32/8] |= 1;
230 
231 	/* set Rx highest rate */
232 	ht_cap.mcs.rx_highest = ht_cap_ie->mcs.rx_highest;
233 
234 	if (ht_cap.cap & IEEE80211_HT_CAP_MAX_AMSDU)
235 		sta->sta.max_amsdu_len = IEEE80211_MAX_MPDU_LEN_HT_7935;
236 	else
237 		sta->sta.max_amsdu_len = IEEE80211_MAX_MPDU_LEN_HT_3839;
238 
239  apply:
240 	changed = memcmp(&sta->sta.ht_cap, &ht_cap, sizeof(ht_cap));
241 
242 	memcpy(&sta->sta.ht_cap, &ht_cap, sizeof(ht_cap));
243 
244 	switch (sdata->vif.bss_conf.chandef.width) {
245 	default:
246 		WARN_ON_ONCE(1);
247 		/* fall through */
248 	case NL80211_CHAN_WIDTH_20_NOHT:
249 	case NL80211_CHAN_WIDTH_20:
250 		bw = IEEE80211_STA_RX_BW_20;
251 		break;
252 	case NL80211_CHAN_WIDTH_40:
253 	case NL80211_CHAN_WIDTH_80:
254 	case NL80211_CHAN_WIDTH_80P80:
255 	case NL80211_CHAN_WIDTH_160:
256 		bw = ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40 ?
257 				IEEE80211_STA_RX_BW_40 : IEEE80211_STA_RX_BW_20;
258 		break;
259 	}
260 
261 	sta->sta.bandwidth = bw;
262 
263 	sta->cur_max_bandwidth =
264 		ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40 ?
265 				IEEE80211_STA_RX_BW_40 : IEEE80211_STA_RX_BW_20;
266 
267 	switch ((ht_cap.cap & IEEE80211_HT_CAP_SM_PS)
268 			>> IEEE80211_HT_CAP_SM_PS_SHIFT) {
269 	case WLAN_HT_CAP_SM_PS_INVALID:
270 	case WLAN_HT_CAP_SM_PS_STATIC:
271 		smps_mode = IEEE80211_SMPS_STATIC;
272 		break;
273 	case WLAN_HT_CAP_SM_PS_DYNAMIC:
274 		smps_mode = IEEE80211_SMPS_DYNAMIC;
275 		break;
276 	case WLAN_HT_CAP_SM_PS_DISABLED:
277 		smps_mode = IEEE80211_SMPS_OFF;
278 		break;
279 	}
280 
281 	if (smps_mode != sta->sta.smps_mode)
282 		changed = true;
283 	sta->sta.smps_mode = smps_mode;
284 
285 	return changed;
286 }
287 
288 void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta,
289 					 enum ieee80211_agg_stop_reason reason)
290 {
291 	int i;
292 
293 	for (i = 0; i <  IEEE80211_NUM_TIDS; i++) {
294 		__ieee80211_stop_tx_ba_session(sta, i, reason);
295 		__ieee80211_stop_rx_ba_session(sta, i, WLAN_BACK_RECIPIENT,
296 					       WLAN_REASON_QSTA_LEAVE_QBSS,
297 					       reason != AGG_STOP_DESTROY_STA &&
298 					       reason != AGG_STOP_PEER_REQUEST);
299 	}
300 
301 	/* stopping might queue the work again - so cancel only afterwards */
302 	cancel_work_sync(&sta->ampdu_mlme.work);
303 }
304 
305 void ieee80211_ba_session_work(struct work_struct *work)
306 {
307 	struct sta_info *sta =
308 		container_of(work, struct sta_info, ampdu_mlme.work);
309 	struct tid_ampdu_tx *tid_tx;
310 	int tid;
311 
312 	/*
313 	 * When this flag is set, new sessions should be
314 	 * blocked, and existing sessions will be torn
315 	 * down by the code that set the flag, so this
316 	 * need not run.
317 	 */
318 	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA))
319 		return;
320 
321 	mutex_lock(&sta->ampdu_mlme.mtx);
322 	for (tid = 0; tid < IEEE80211_NUM_TIDS; tid++) {
323 		if (test_and_clear_bit(tid, sta->ampdu_mlme.tid_rx_timer_expired))
324 			___ieee80211_stop_rx_ba_session(
325 				sta, tid, WLAN_BACK_RECIPIENT,
326 				WLAN_REASON_QSTA_TIMEOUT, true);
327 
328 		if (test_and_clear_bit(tid,
329 				       sta->ampdu_mlme.tid_rx_stop_requested))
330 			___ieee80211_stop_rx_ba_session(
331 				sta, tid, WLAN_BACK_RECIPIENT,
332 				WLAN_REASON_UNSPECIFIED, true);
333 
334 		if (test_and_clear_bit(tid,
335 				       sta->ampdu_mlme.tid_rx_manage_offl))
336 			__ieee80211_start_rx_ba_session(sta, 0, 0, 0, 1, tid,
337 							IEEE80211_MAX_AMPDU_BUF,
338 							false, true);
339 
340 		if (test_and_clear_bit(tid + IEEE80211_NUM_TIDS,
341 				       sta->ampdu_mlme.tid_rx_manage_offl))
342 			___ieee80211_stop_rx_ba_session(
343 				sta, tid, WLAN_BACK_RECIPIENT,
344 				0, false);
345 
346 		spin_lock_bh(&sta->lock);
347 
348 		tid_tx = sta->ampdu_mlme.tid_start_tx[tid];
349 		if (tid_tx) {
350 			/*
351 			 * Assign it over to the normal tid_tx array
352 			 * where it "goes live".
353 			 */
354 
355 			sta->ampdu_mlme.tid_start_tx[tid] = NULL;
356 			/* could there be a race? */
357 			if (sta->ampdu_mlme.tid_tx[tid])
358 				kfree(tid_tx);
359 			else
360 				ieee80211_assign_tid_tx(sta, tid, tid_tx);
361 			spin_unlock_bh(&sta->lock);
362 
363 			ieee80211_tx_ba_session_handle_start(sta, tid);
364 			continue;
365 		}
366 		spin_unlock_bh(&sta->lock);
367 
368 		tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
369 		if (!tid_tx)
370 			continue;
371 
372 		if (test_and_clear_bit(HT_AGG_STATE_START_CB, &tid_tx->state))
373 			ieee80211_start_tx_ba_cb(sta, tid, tid_tx);
374 		if (test_and_clear_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state))
375 			___ieee80211_stop_tx_ba_session(sta, tid,
376 							AGG_STOP_LOCAL_REQUEST);
377 		if (test_and_clear_bit(HT_AGG_STATE_STOP_CB, &tid_tx->state))
378 			ieee80211_stop_tx_ba_cb(sta, tid, tid_tx);
379 	}
380 	mutex_unlock(&sta->ampdu_mlme.mtx);
381 }
382 
383 void ieee80211_send_delba(struct ieee80211_sub_if_data *sdata,
384 			  const u8 *da, u16 tid,
385 			  u16 initiator, u16 reason_code)
386 {
387 	struct ieee80211_local *local = sdata->local;
388 	struct sk_buff *skb;
389 	struct ieee80211_mgmt *mgmt;
390 	u16 params;
391 
392 	skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
393 	if (!skb)
394 		return;
395 
396 	skb_reserve(skb, local->hw.extra_tx_headroom);
397 	mgmt = skb_put_zero(skb, 24);
398 	memcpy(mgmt->da, da, ETH_ALEN);
399 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
400 	if (sdata->vif.type == NL80211_IFTYPE_AP ||
401 	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN ||
402 	    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
403 		memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
404 	else if (sdata->vif.type == NL80211_IFTYPE_STATION)
405 		memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);
406 	else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
407 		memcpy(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN);
408 
409 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
410 					  IEEE80211_STYPE_ACTION);
411 
412 	skb_put(skb, 1 + sizeof(mgmt->u.action.u.delba));
413 
414 	mgmt->u.action.category = WLAN_CATEGORY_BACK;
415 	mgmt->u.action.u.delba.action_code = WLAN_ACTION_DELBA;
416 	params = (u16)(initiator << 11); 	/* bit 11 initiator */
417 	params |= (u16)(tid << 12); 		/* bit 15:12 TID number */
418 
419 	mgmt->u.action.u.delba.params = cpu_to_le16(params);
420 	mgmt->u.action.u.delba.reason_code = cpu_to_le16(reason_code);
421 
422 	ieee80211_tx_skb(sdata, skb);
423 }
424 
425 void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata,
426 			     struct sta_info *sta,
427 			     struct ieee80211_mgmt *mgmt, size_t len)
428 {
429 	u16 tid, params;
430 	u16 initiator;
431 
432 	params = le16_to_cpu(mgmt->u.action.u.delba.params);
433 	tid = (params & IEEE80211_DELBA_PARAM_TID_MASK) >> 12;
434 	initiator = (params & IEEE80211_DELBA_PARAM_INITIATOR_MASK) >> 11;
435 
436 	ht_dbg_ratelimited(sdata, "delba from %pM (%s) tid %d reason code %d\n",
437 			   mgmt->sa, initiator ? "initiator" : "recipient",
438 			   tid,
439 			   le16_to_cpu(mgmt->u.action.u.delba.reason_code));
440 
441 	if (initiator == WLAN_BACK_INITIATOR)
442 		__ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_INITIATOR, 0,
443 					       true);
444 	else
445 		__ieee80211_stop_tx_ba_session(sta, tid, AGG_STOP_PEER_REQUEST);
446 }
447 
448 int ieee80211_send_smps_action(struct ieee80211_sub_if_data *sdata,
449 			       enum ieee80211_smps_mode smps, const u8 *da,
450 			       const u8 *bssid)
451 {
452 	struct ieee80211_local *local = sdata->local;
453 	struct sk_buff *skb;
454 	struct ieee80211_mgmt *action_frame;
455 
456 	/* 27 = header + category + action + smps mode */
457 	skb = dev_alloc_skb(27 + local->hw.extra_tx_headroom);
458 	if (!skb)
459 		return -ENOMEM;
460 
461 	skb_reserve(skb, local->hw.extra_tx_headroom);
462 	action_frame = skb_put(skb, 27);
463 	memcpy(action_frame->da, da, ETH_ALEN);
464 	memcpy(action_frame->sa, sdata->dev->dev_addr, ETH_ALEN);
465 	memcpy(action_frame->bssid, bssid, ETH_ALEN);
466 	action_frame->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
467 						  IEEE80211_STYPE_ACTION);
468 	action_frame->u.action.category = WLAN_CATEGORY_HT;
469 	action_frame->u.action.u.ht_smps.action = WLAN_HT_ACTION_SMPS;
470 	switch (smps) {
471 	case IEEE80211_SMPS_AUTOMATIC:
472 	case IEEE80211_SMPS_NUM_MODES:
473 		WARN_ON(1);
474 	case IEEE80211_SMPS_OFF:
475 		action_frame->u.action.u.ht_smps.smps_control =
476 				WLAN_HT_SMPS_CONTROL_DISABLED;
477 		break;
478 	case IEEE80211_SMPS_STATIC:
479 		action_frame->u.action.u.ht_smps.smps_control =
480 				WLAN_HT_SMPS_CONTROL_STATIC;
481 		break;
482 	case IEEE80211_SMPS_DYNAMIC:
483 		action_frame->u.action.u.ht_smps.smps_control =
484 				WLAN_HT_SMPS_CONTROL_DYNAMIC;
485 		break;
486 	}
487 
488 	/* we'll do more on status of this frame */
489 	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
490 	ieee80211_tx_skb(sdata, skb);
491 
492 	return 0;
493 }
494 
495 void ieee80211_request_smps_mgd_work(struct work_struct *work)
496 {
497 	struct ieee80211_sub_if_data *sdata =
498 		container_of(work, struct ieee80211_sub_if_data,
499 			     u.mgd.request_smps_work);
500 
501 	sdata_lock(sdata);
502 	__ieee80211_request_smps_mgd(sdata, sdata->u.mgd.driver_smps_mode);
503 	sdata_unlock(sdata);
504 }
505 
506 void ieee80211_request_smps_ap_work(struct work_struct *work)
507 {
508 	struct ieee80211_sub_if_data *sdata =
509 		container_of(work, struct ieee80211_sub_if_data,
510 			     u.ap.request_smps_work);
511 
512 	sdata_lock(sdata);
513 	if (sdata_dereference(sdata->u.ap.beacon, sdata))
514 		__ieee80211_request_smps_ap(sdata,
515 					    sdata->u.ap.driver_smps_mode);
516 	sdata_unlock(sdata);
517 }
518 
519 void ieee80211_request_smps(struct ieee80211_vif *vif,
520 			    enum ieee80211_smps_mode smps_mode)
521 {
522 	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
523 
524 	if (WARN_ON_ONCE(vif->type != NL80211_IFTYPE_STATION &&
525 			 vif->type != NL80211_IFTYPE_AP))
526 		return;
527 
528 	if (vif->type == NL80211_IFTYPE_STATION) {
529 		if (sdata->u.mgd.driver_smps_mode == smps_mode)
530 			return;
531 		sdata->u.mgd.driver_smps_mode = smps_mode;
532 		ieee80211_queue_work(&sdata->local->hw,
533 				     &sdata->u.mgd.request_smps_work);
534 	} else {
535 		/* AUTOMATIC is meaningless in AP mode */
536 		if (WARN_ON_ONCE(smps_mode == IEEE80211_SMPS_AUTOMATIC))
537 			return;
538 		if (sdata->u.ap.driver_smps_mode == smps_mode)
539 			return;
540 		sdata->u.ap.driver_smps_mode = smps_mode;
541 		ieee80211_queue_work(&sdata->local->hw,
542 				     &sdata->u.ap.request_smps_work);
543 	}
544 }
545 /* this might change ... don't want non-open drivers using it */
546 EXPORT_SYMBOL_GPL(ieee80211_request_smps);
547