xref: /openbmc/linux/drivers/net/wireless/ath/ath9k/recv.c (revision fd589a8f)
1 /*
2  * Copyright (c) 2008-2009 Atheros Communications Inc.
3  *
4  * Permission to use, copy, modify, and/or distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "ath9k.h"
18 
19 static struct ieee80211_hw * ath_get_virt_hw(struct ath_softc *sc,
20 					     struct ieee80211_hdr *hdr)
21 {
22 	struct ieee80211_hw *hw = sc->pri_wiphy->hw;
23 	int i;
24 
25 	spin_lock_bh(&sc->wiphy_lock);
26 	for (i = 0; i < sc->num_sec_wiphy; i++) {
27 		struct ath_wiphy *aphy = sc->sec_wiphy[i];
28 		if (aphy == NULL)
29 			continue;
30 		if (compare_ether_addr(hdr->addr1, aphy->hw->wiphy->perm_addr)
31 		    == 0) {
32 			hw = aphy->hw;
33 			break;
34 		}
35 	}
36 	spin_unlock_bh(&sc->wiphy_lock);
37 	return hw;
38 }
39 
40 /*
41  * Setup and link descriptors.
42  *
43  * 11N: we can no longer afford to self link the last descriptor.
44  * MAC acknowledges BA status as long as it copies frames to host
45  * buffer (or rx fifo). This can incorrectly acknowledge packets
46  * to a sender if last desc is self-linked.
47  */
48 static void ath_rx_buf_link(struct ath_softc *sc, struct ath_buf *bf)
49 {
50 	struct ath_hw *ah = sc->sc_ah;
51 	struct ath_desc *ds;
52 	struct sk_buff *skb;
53 
54 	ATH_RXBUF_RESET(bf);
55 
56 	ds = bf->bf_desc;
57 	ds->ds_link = 0; /* link to null */
58 	ds->ds_data = bf->bf_buf_addr;
59 
60 	/* virtual addr of the beginning of the buffer. */
61 	skb = bf->bf_mpdu;
62 	ASSERT(skb != NULL);
63 	ds->ds_vdata = skb->data;
64 
65 	/* setup rx descriptors. The rx.bufsize here tells the harware
66 	 * how much data it can DMA to us and that we are prepared
67 	 * to process */
68 	ath9k_hw_setuprxdesc(ah, ds,
69 			     sc->rx.bufsize,
70 			     0);
71 
72 	if (sc->rx.rxlink == NULL)
73 		ath9k_hw_putrxbuf(ah, bf->bf_daddr);
74 	else
75 		*sc->rx.rxlink = bf->bf_daddr;
76 
77 	sc->rx.rxlink = &ds->ds_link;
78 	ath9k_hw_rxena(ah);
79 }
80 
81 static void ath_setdefantenna(struct ath_softc *sc, u32 antenna)
82 {
83 	/* XXX block beacon interrupts */
84 	ath9k_hw_setantenna(sc->sc_ah, antenna);
85 	sc->rx.defant = antenna;
86 	sc->rx.rxotherant = 0;
87 }
88 
89 /*
90  *  Extend 15-bit time stamp from rx descriptor to
91  *  a full 64-bit TSF using the current h/w TSF.
92 */
93 static u64 ath_extend_tsf(struct ath_softc *sc, u32 rstamp)
94 {
95 	u64 tsf;
96 
97 	tsf = ath9k_hw_gettsf64(sc->sc_ah);
98 	if ((tsf & 0x7fff) < rstamp)
99 		tsf -= 0x8000;
100 	return (tsf & ~0x7fff) | rstamp;
101 }
102 
103 /*
104  * For Decrypt or Demic errors, we only mark packet status here and always push
105  * up the frame up to let mac80211 handle the actual error case, be it no
106  * decryption key or real decryption error. This let us keep statistics there.
107  */
108 static int ath_rx_prepare(struct sk_buff *skb, struct ath_desc *ds,
109 			  struct ieee80211_rx_status *rx_status, bool *decrypt_error,
110 			  struct ath_softc *sc)
111 {
112 	struct ieee80211_hdr *hdr;
113 	u8 ratecode;
114 	__le16 fc;
115 	struct ieee80211_hw *hw;
116 	struct ieee80211_sta *sta;
117 	struct ath_node *an;
118 	int last_rssi = ATH_RSSI_DUMMY_MARKER;
119 
120 
121 	hdr = (struct ieee80211_hdr *)skb->data;
122 	fc = hdr->frame_control;
123 	memset(rx_status, 0, sizeof(struct ieee80211_rx_status));
124 	hw = ath_get_virt_hw(sc, hdr);
125 
126 	if (ds->ds_rxstat.rs_more) {
127 		/*
128 		 * Frame spans multiple descriptors; this cannot happen yet
129 		 * as we don't support jumbograms. If not in monitor mode,
130 		 * discard the frame. Enable this if you want to see
131 		 * error frames in Monitor mode.
132 		 */
133 		if (sc->sc_ah->opmode != NL80211_IFTYPE_MONITOR)
134 			goto rx_next;
135 	} else if (ds->ds_rxstat.rs_status != 0) {
136 		if (ds->ds_rxstat.rs_status & ATH9K_RXERR_CRC)
137 			rx_status->flag |= RX_FLAG_FAILED_FCS_CRC;
138 		if (ds->ds_rxstat.rs_status & ATH9K_RXERR_PHY)
139 			goto rx_next;
140 
141 		if (ds->ds_rxstat.rs_status & ATH9K_RXERR_DECRYPT) {
142 			*decrypt_error = true;
143 		} else if (ds->ds_rxstat.rs_status & ATH9K_RXERR_MIC) {
144 			if (ieee80211_is_ctl(fc))
145 				/*
146 				 * Sometimes, we get invalid
147 				 * MIC failures on valid control frames.
148 				 * Remove these mic errors.
149 				 */
150 				ds->ds_rxstat.rs_status &= ~ATH9K_RXERR_MIC;
151 			else
152 				rx_status->flag |= RX_FLAG_MMIC_ERROR;
153 		}
154 		/*
155 		 * Reject error frames with the exception of
156 		 * decryption and MIC failures. For monitor mode,
157 		 * we also ignore the CRC error.
158 		 */
159 		if (sc->sc_ah->opmode == NL80211_IFTYPE_MONITOR) {
160 			if (ds->ds_rxstat.rs_status &
161 			    ~(ATH9K_RXERR_DECRYPT | ATH9K_RXERR_MIC |
162 			      ATH9K_RXERR_CRC))
163 				goto rx_next;
164 		} else {
165 			if (ds->ds_rxstat.rs_status &
166 			    ~(ATH9K_RXERR_DECRYPT | ATH9K_RXERR_MIC)) {
167 				goto rx_next;
168 			}
169 		}
170 	}
171 
172 	ratecode = ds->ds_rxstat.rs_rate;
173 
174 	if (ratecode & 0x80) {
175 		/* HT rate */
176 		rx_status->flag |= RX_FLAG_HT;
177 		if (ds->ds_rxstat.rs_flags & ATH9K_RX_2040)
178 			rx_status->flag |= RX_FLAG_40MHZ;
179 		if (ds->ds_rxstat.rs_flags & ATH9K_RX_GI)
180 			rx_status->flag |= RX_FLAG_SHORT_GI;
181 		rx_status->rate_idx = ratecode & 0x7f;
182 	} else {
183 		int i = 0, cur_band, n_rates;
184 
185 		cur_band = hw->conf.channel->band;
186 		n_rates = sc->sbands[cur_band].n_bitrates;
187 
188 		for (i = 0; i < n_rates; i++) {
189 			if (sc->sbands[cur_band].bitrates[i].hw_value ==
190 			    ratecode) {
191 				rx_status->rate_idx = i;
192 				break;
193 			}
194 
195 			if (sc->sbands[cur_band].bitrates[i].hw_value_short ==
196 			    ratecode) {
197 				rx_status->rate_idx = i;
198 				rx_status->flag |= RX_FLAG_SHORTPRE;
199 				break;
200 			}
201 		}
202 	}
203 
204 	rcu_read_lock();
205 	sta = ieee80211_find_sta(sc->hw, hdr->addr2);
206 	if (sta) {
207 		an = (struct ath_node *) sta->drv_priv;
208 		if (ds->ds_rxstat.rs_rssi != ATH9K_RSSI_BAD &&
209 		   !ds->ds_rxstat.rs_moreaggr)
210 			ATH_RSSI_LPF(an->last_rssi, ds->ds_rxstat.rs_rssi);
211 		last_rssi = an->last_rssi;
212 	}
213 	rcu_read_unlock();
214 
215 	if (likely(last_rssi != ATH_RSSI_DUMMY_MARKER))
216 		ds->ds_rxstat.rs_rssi = ATH_EP_RND(last_rssi,
217 					ATH_RSSI_EP_MULTIPLIER);
218 	if (ds->ds_rxstat.rs_rssi < 0)
219 		ds->ds_rxstat.rs_rssi = 0;
220 	else if (ds->ds_rxstat.rs_rssi > 127)
221 		ds->ds_rxstat.rs_rssi = 127;
222 
223 	/* Update Beacon RSSI, this is used by ANI. */
224 	if (ieee80211_is_beacon(fc))
225 		sc->sc_ah->stats.avgbrssi = ds->ds_rxstat.rs_rssi;
226 
227 	rx_status->mactime = ath_extend_tsf(sc, ds->ds_rxstat.rs_tstamp);
228 	rx_status->band = hw->conf.channel->band;
229 	rx_status->freq = hw->conf.channel->center_freq;
230 	rx_status->noise = sc->ani.noise_floor;
231 	rx_status->signal = ATH_DEFAULT_NOISE_FLOOR + ds->ds_rxstat.rs_rssi;
232 	rx_status->antenna = ds->ds_rxstat.rs_antenna;
233 
234 	/*
235 	 * Theory for reporting quality:
236 	 *
237 	 * At a hardware RSSI of 45 you will be able to use MCS 7  reliably.
238 	 * At a hardware RSSI of 45 you will be able to use MCS 15 reliably.
239 	 * At a hardware RSSI of 35 you should be able use 54 Mbps reliably.
240 	 *
241 	 * MCS 7  is the highets MCS index usable by a 1-stream device.
242 	 * MCS 15 is the highest MCS index usable by a 2-stream device.
243 	 *
244 	 * All ath9k devices are either 1-stream or 2-stream.
245 	 *
246 	 * How many bars you see is derived from the qual reporting.
247 	 *
248 	 * A more elaborate scheme can be used here but it requires tables
249 	 * of SNR/throughput for each possible mode used. For the MCS table
250 	 * you can refer to the wireless wiki:
251 	 *
252 	 * http://wireless.kernel.org/en/developers/Documentation/ieee80211/802.11n
253 	 *
254 	 */
255 	if (conf_is_ht(&hw->conf))
256 		rx_status->qual =  ds->ds_rxstat.rs_rssi * 100 / 45;
257 	else
258 		rx_status->qual =  ds->ds_rxstat.rs_rssi * 100 / 35;
259 
260 	/* rssi can be more than 45 though, anything above that
261 	 * should be considered at 100% */
262 	if (rx_status->qual > 100)
263 		rx_status->qual = 100;
264 
265 	rx_status->flag |= RX_FLAG_TSFT;
266 
267 	return 1;
268 rx_next:
269 	return 0;
270 }
271 
272 static void ath_opmode_init(struct ath_softc *sc)
273 {
274 	struct ath_hw *ah = sc->sc_ah;
275 	u32 rfilt, mfilt[2];
276 
277 	/* configure rx filter */
278 	rfilt = ath_calcrxfilter(sc);
279 	ath9k_hw_setrxfilter(ah, rfilt);
280 
281 	/* configure bssid mask */
282 	if (ah->caps.hw_caps & ATH9K_HW_CAP_BSSIDMASK)
283 		ath9k_hw_setbssidmask(sc);
284 
285 	/* configure operational mode */
286 	ath9k_hw_setopmode(ah);
287 
288 	/* Handle any link-level address change. */
289 	ath9k_hw_setmac(ah, sc->sc_ah->macaddr);
290 
291 	/* calculate and install multicast filter */
292 	mfilt[0] = mfilt[1] = ~0;
293 	ath9k_hw_setmcastfilter(ah, mfilt[0], mfilt[1]);
294 }
295 
296 int ath_rx_init(struct ath_softc *sc, int nbufs)
297 {
298 	struct sk_buff *skb;
299 	struct ath_buf *bf;
300 	int error = 0;
301 
302 	spin_lock_init(&sc->rx.rxflushlock);
303 	sc->sc_flags &= ~SC_OP_RXFLUSH;
304 	spin_lock_init(&sc->rx.rxbuflock);
305 
306 	sc->rx.bufsize = roundup(IEEE80211_MAX_MPDU_LEN,
307 				 min(sc->common.cachelsz, (u16)64));
308 
309 	DPRINTF(sc, ATH_DBG_CONFIG, "cachelsz %u rxbufsize %u\n",
310 		sc->common.cachelsz, sc->rx.bufsize);
311 
312 	/* Initialize rx descriptors */
313 
314 	error = ath_descdma_setup(sc, &sc->rx.rxdma, &sc->rx.rxbuf,
315 				  "rx", nbufs, 1);
316 	if (error != 0) {
317 		DPRINTF(sc, ATH_DBG_FATAL,
318 			"failed to allocate rx descriptors: %d\n", error);
319 		goto err;
320 	}
321 
322 	list_for_each_entry(bf, &sc->rx.rxbuf, list) {
323 		skb = ath_rxbuf_alloc(&sc->common, sc->rx.bufsize, GFP_KERNEL);
324 		if (skb == NULL) {
325 			error = -ENOMEM;
326 			goto err;
327 		}
328 
329 		bf->bf_mpdu = skb;
330 		bf->bf_buf_addr = dma_map_single(sc->dev, skb->data,
331 						 sc->rx.bufsize,
332 						 DMA_FROM_DEVICE);
333 		if (unlikely(dma_mapping_error(sc->dev,
334 					       bf->bf_buf_addr))) {
335 			dev_kfree_skb_any(skb);
336 			bf->bf_mpdu = NULL;
337 			DPRINTF(sc, ATH_DBG_FATAL,
338 				"dma_mapping_error() on RX init\n");
339 			error = -ENOMEM;
340 			goto err;
341 		}
342 		bf->bf_dmacontext = bf->bf_buf_addr;
343 	}
344 	sc->rx.rxlink = NULL;
345 
346 err:
347 	if (error)
348 		ath_rx_cleanup(sc);
349 
350 	return error;
351 }
352 
353 void ath_rx_cleanup(struct ath_softc *sc)
354 {
355 	struct sk_buff *skb;
356 	struct ath_buf *bf;
357 
358 	list_for_each_entry(bf, &sc->rx.rxbuf, list) {
359 		skb = bf->bf_mpdu;
360 		if (skb) {
361 			dma_unmap_single(sc->dev, bf->bf_buf_addr,
362 					 sc->rx.bufsize, DMA_FROM_DEVICE);
363 			dev_kfree_skb(skb);
364 		}
365 	}
366 
367 	if (sc->rx.rxdma.dd_desc_len != 0)
368 		ath_descdma_cleanup(sc, &sc->rx.rxdma, &sc->rx.rxbuf);
369 }
370 
371 /*
372  * Calculate the receive filter according to the
373  * operating mode and state:
374  *
375  * o always accept unicast, broadcast, and multicast traffic
376  * o maintain current state of phy error reception (the hal
377  *   may enable phy error frames for noise immunity work)
378  * o probe request frames are accepted only when operating in
379  *   hostap, adhoc, or monitor modes
380  * o enable promiscuous mode according to the interface state
381  * o accept beacons:
382  *   - when operating in adhoc mode so the 802.11 layer creates
383  *     node table entries for peers,
384  *   - when operating in station mode for collecting rssi data when
385  *     the station is otherwise quiet, or
386  *   - when operating as a repeater so we see repeater-sta beacons
387  *   - when scanning
388  */
389 
390 u32 ath_calcrxfilter(struct ath_softc *sc)
391 {
392 #define	RX_FILTER_PRESERVE (ATH9K_RX_FILTER_PHYERR | ATH9K_RX_FILTER_PHYRADAR)
393 
394 	u32 rfilt;
395 
396 	rfilt = (ath9k_hw_getrxfilter(sc->sc_ah) & RX_FILTER_PRESERVE)
397 		| ATH9K_RX_FILTER_UCAST | ATH9K_RX_FILTER_BCAST
398 		| ATH9K_RX_FILTER_MCAST;
399 
400 	/* If not a STA, enable processing of Probe Requests */
401 	if (sc->sc_ah->opmode != NL80211_IFTYPE_STATION)
402 		rfilt |= ATH9K_RX_FILTER_PROBEREQ;
403 
404 	/*
405 	 * Set promiscuous mode when FIF_PROMISC_IN_BSS is enabled for station
406 	 * mode interface or when in monitor mode. AP mode does not need this
407 	 * since it receives all in-BSS frames anyway.
408 	 */
409 	if (((sc->sc_ah->opmode != NL80211_IFTYPE_AP) &&
410 	     (sc->rx.rxfilter & FIF_PROMISC_IN_BSS)) ||
411 	    (sc->sc_ah->opmode == NL80211_IFTYPE_MONITOR))
412 		rfilt |= ATH9K_RX_FILTER_PROM;
413 
414 	if (sc->rx.rxfilter & FIF_CONTROL)
415 		rfilt |= ATH9K_RX_FILTER_CONTROL;
416 
417 	if ((sc->sc_ah->opmode == NL80211_IFTYPE_STATION) &&
418 	    !(sc->rx.rxfilter & FIF_BCN_PRBRESP_PROMISC))
419 		rfilt |= ATH9K_RX_FILTER_MYBEACON;
420 	else
421 		rfilt |= ATH9K_RX_FILTER_BEACON;
422 
423 	if (sc->rx.rxfilter & FIF_PSPOLL)
424 		rfilt |= ATH9K_RX_FILTER_PSPOLL;
425 
426 	if (conf_is_ht(&sc->hw->conf))
427 		rfilt |= ATH9K_RX_FILTER_COMP_BAR;
428 
429 	if (sc->sec_wiphy || (sc->rx.rxfilter & FIF_OTHER_BSS)) {
430 		/* TODO: only needed if more than one BSSID is in use in
431 		 * station/adhoc mode */
432 		/* The following may also be needed for other older chips */
433 		if (sc->sc_ah->hw_version.macVersion == AR_SREV_VERSION_9160)
434 			rfilt |= ATH9K_RX_FILTER_PROM;
435 		rfilt |= ATH9K_RX_FILTER_MCAST_BCAST_ALL;
436 	}
437 
438 	return rfilt;
439 
440 #undef RX_FILTER_PRESERVE
441 }
442 
443 int ath_startrecv(struct ath_softc *sc)
444 {
445 	struct ath_hw *ah = sc->sc_ah;
446 	struct ath_buf *bf, *tbf;
447 
448 	spin_lock_bh(&sc->rx.rxbuflock);
449 	if (list_empty(&sc->rx.rxbuf))
450 		goto start_recv;
451 
452 	sc->rx.rxlink = NULL;
453 	list_for_each_entry_safe(bf, tbf, &sc->rx.rxbuf, list) {
454 		ath_rx_buf_link(sc, bf);
455 	}
456 
457 	/* We could have deleted elements so the list may be empty now */
458 	if (list_empty(&sc->rx.rxbuf))
459 		goto start_recv;
460 
461 	bf = list_first_entry(&sc->rx.rxbuf, struct ath_buf, list);
462 	ath9k_hw_putrxbuf(ah, bf->bf_daddr);
463 	ath9k_hw_rxena(ah);
464 
465 start_recv:
466 	spin_unlock_bh(&sc->rx.rxbuflock);
467 	ath_opmode_init(sc);
468 	ath9k_hw_startpcureceive(ah);
469 
470 	return 0;
471 }
472 
473 bool ath_stoprecv(struct ath_softc *sc)
474 {
475 	struct ath_hw *ah = sc->sc_ah;
476 	bool stopped;
477 
478 	ath9k_hw_stoppcurecv(ah);
479 	ath9k_hw_setrxfilter(ah, 0);
480 	stopped = ath9k_hw_stopdmarecv(ah);
481 	sc->rx.rxlink = NULL;
482 
483 	return stopped;
484 }
485 
486 void ath_flushrecv(struct ath_softc *sc)
487 {
488 	spin_lock_bh(&sc->rx.rxflushlock);
489 	sc->sc_flags |= SC_OP_RXFLUSH;
490 	ath_rx_tasklet(sc, 1);
491 	sc->sc_flags &= ~SC_OP_RXFLUSH;
492 	spin_unlock_bh(&sc->rx.rxflushlock);
493 }
494 
495 static bool ath_beacon_dtim_pending_cab(struct sk_buff *skb)
496 {
497 	/* Check whether the Beacon frame has DTIM indicating buffered bc/mc */
498 	struct ieee80211_mgmt *mgmt;
499 	u8 *pos, *end, id, elen;
500 	struct ieee80211_tim_ie *tim;
501 
502 	mgmt = (struct ieee80211_mgmt *)skb->data;
503 	pos = mgmt->u.beacon.variable;
504 	end = skb->data + skb->len;
505 
506 	while (pos + 2 < end) {
507 		id = *pos++;
508 		elen = *pos++;
509 		if (pos + elen > end)
510 			break;
511 
512 		if (id == WLAN_EID_TIM) {
513 			if (elen < sizeof(*tim))
514 				break;
515 			tim = (struct ieee80211_tim_ie *) pos;
516 			if (tim->dtim_count != 0)
517 				break;
518 			return tim->bitmap_ctrl & 0x01;
519 		}
520 
521 		pos += elen;
522 	}
523 
524 	return false;
525 }
526 
527 static void ath_rx_ps_beacon(struct ath_softc *sc, struct sk_buff *skb)
528 {
529 	struct ieee80211_mgmt *mgmt;
530 
531 	if (skb->len < 24 + 8 + 2 + 2)
532 		return;
533 
534 	mgmt = (struct ieee80211_mgmt *)skb->data;
535 	if (memcmp(sc->curbssid, mgmt->bssid, ETH_ALEN) != 0)
536 		return; /* not from our current AP */
537 
538 	sc->sc_flags &= ~SC_OP_WAIT_FOR_BEACON;
539 
540 	if (sc->sc_flags & SC_OP_BEACON_SYNC) {
541 		sc->sc_flags &= ~SC_OP_BEACON_SYNC;
542 		DPRINTF(sc, ATH_DBG_PS, "Reconfigure Beacon timers based on "
543 			"timestamp from the AP\n");
544 		ath_beacon_config(sc, NULL);
545 	}
546 
547 	if (ath_beacon_dtim_pending_cab(skb)) {
548 		/*
549 		 * Remain awake waiting for buffered broadcast/multicast
550 		 * frames. If the last broadcast/multicast frame is not
551 		 * received properly, the next beacon frame will work as
552 		 * a backup trigger for returning into NETWORK SLEEP state,
553 		 * so we are waiting for it as well.
554 		 */
555 		DPRINTF(sc, ATH_DBG_PS, "Received DTIM beacon indicating "
556 			"buffered broadcast/multicast frame(s)\n");
557 		sc->sc_flags |= SC_OP_WAIT_FOR_CAB | SC_OP_WAIT_FOR_BEACON;
558 		return;
559 	}
560 
561 	if (sc->sc_flags & SC_OP_WAIT_FOR_CAB) {
562 		/*
563 		 * This can happen if a broadcast frame is dropped or the AP
564 		 * fails to send a frame indicating that all CAB frames have
565 		 * been delivered.
566 		 */
567 		sc->sc_flags &= ~SC_OP_WAIT_FOR_CAB;
568 		DPRINTF(sc, ATH_DBG_PS, "PS wait for CAB frames timed out\n");
569 	}
570 }
571 
572 static void ath_rx_ps(struct ath_softc *sc, struct sk_buff *skb)
573 {
574 	struct ieee80211_hdr *hdr;
575 
576 	hdr = (struct ieee80211_hdr *)skb->data;
577 
578 	/* Process Beacon and CAB receive in PS state */
579 	if ((sc->sc_flags & SC_OP_WAIT_FOR_BEACON) &&
580 	    ieee80211_is_beacon(hdr->frame_control))
581 		ath_rx_ps_beacon(sc, skb);
582 	else if ((sc->sc_flags & SC_OP_WAIT_FOR_CAB) &&
583 		 (ieee80211_is_data(hdr->frame_control) ||
584 		  ieee80211_is_action(hdr->frame_control)) &&
585 		 is_multicast_ether_addr(hdr->addr1) &&
586 		 !ieee80211_has_moredata(hdr->frame_control)) {
587 		/*
588 		 * No more broadcast/multicast frames to be received at this
589 		 * point.
590 		 */
591 		sc->sc_flags &= ~SC_OP_WAIT_FOR_CAB;
592 		DPRINTF(sc, ATH_DBG_PS, "All PS CAB frames received, back to "
593 			"sleep\n");
594 	} else if ((sc->sc_flags & SC_OP_WAIT_FOR_PSPOLL_DATA) &&
595 		   !is_multicast_ether_addr(hdr->addr1) &&
596 		   !ieee80211_has_morefrags(hdr->frame_control)) {
597 		sc->sc_flags &= ~SC_OP_WAIT_FOR_PSPOLL_DATA;
598 		DPRINTF(sc, ATH_DBG_PS, "Going back to sleep after having "
599 			"received PS-Poll data (0x%x)\n",
600 			sc->sc_flags & (SC_OP_WAIT_FOR_BEACON |
601 					SC_OP_WAIT_FOR_CAB |
602 					SC_OP_WAIT_FOR_PSPOLL_DATA |
603 					SC_OP_WAIT_FOR_TX_ACK));
604 	}
605 }
606 
607 static void ath_rx_send_to_mac80211(struct ath_softc *sc, struct sk_buff *skb,
608 				    struct ieee80211_rx_status *rx_status)
609 {
610 	struct ieee80211_hdr *hdr;
611 
612 	hdr = (struct ieee80211_hdr *)skb->data;
613 
614 	/* Send the frame to mac80211 */
615 	if (is_multicast_ether_addr(hdr->addr1)) {
616 		int i;
617 		/*
618 		 * Deliver broadcast/multicast frames to all suitable
619 		 * virtual wiphys.
620 		 */
621 		/* TODO: filter based on channel configuration */
622 		for (i = 0; i < sc->num_sec_wiphy; i++) {
623 			struct ath_wiphy *aphy = sc->sec_wiphy[i];
624 			struct sk_buff *nskb;
625 			if (aphy == NULL)
626 				continue;
627 			nskb = skb_copy(skb, GFP_ATOMIC);
628 			if (nskb) {
629 				memcpy(IEEE80211_SKB_RXCB(nskb), rx_status,
630 					sizeof(*rx_status));
631 				ieee80211_rx(aphy->hw, nskb);
632 			}
633 		}
634 		memcpy(IEEE80211_SKB_RXCB(skb), rx_status, sizeof(*rx_status));
635 		ieee80211_rx(sc->hw, skb);
636 	} else {
637 		/* Deliver unicast frames based on receiver address */
638 		memcpy(IEEE80211_SKB_RXCB(skb), rx_status, sizeof(*rx_status));
639 		ieee80211_rx(ath_get_virt_hw(sc, hdr), skb);
640 	}
641 }
642 
643 int ath_rx_tasklet(struct ath_softc *sc, int flush)
644 {
645 #define PA2DESC(_sc, _pa)                                               \
646 	((struct ath_desc *)((caddr_t)(_sc)->rx.rxdma.dd_desc +		\
647 			     ((_pa) - (_sc)->rx.rxdma.dd_desc_paddr)))
648 
649 	struct ath_buf *bf;
650 	struct ath_desc *ds;
651 	struct sk_buff *skb = NULL, *requeue_skb;
652 	struct ieee80211_rx_status rx_status;
653 	struct ath_hw *ah = sc->sc_ah;
654 	struct ieee80211_hdr *hdr;
655 	int hdrlen, padsize, retval;
656 	bool decrypt_error = false;
657 	u8 keyix;
658 	__le16 fc;
659 
660 	spin_lock_bh(&sc->rx.rxbuflock);
661 
662 	do {
663 		/* If handling rx interrupt and flush is in progress => exit */
664 		if ((sc->sc_flags & SC_OP_RXFLUSH) && (flush == 0))
665 			break;
666 
667 		if (list_empty(&sc->rx.rxbuf)) {
668 			sc->rx.rxlink = NULL;
669 			break;
670 		}
671 
672 		bf = list_first_entry(&sc->rx.rxbuf, struct ath_buf, list);
673 		ds = bf->bf_desc;
674 
675 		/*
676 		 * Must provide the virtual address of the current
677 		 * descriptor, the physical address, and the virtual
678 		 * address of the next descriptor in the h/w chain.
679 		 * This allows the HAL to look ahead to see if the
680 		 * hardware is done with a descriptor by checking the
681 		 * done bit in the following descriptor and the address
682 		 * of the current descriptor the DMA engine is working
683 		 * on.  All this is necessary because of our use of
684 		 * a self-linked list to avoid rx overruns.
685 		 */
686 		retval = ath9k_hw_rxprocdesc(ah, ds,
687 					     bf->bf_daddr,
688 					     PA2DESC(sc, ds->ds_link),
689 					     0);
690 		if (retval == -EINPROGRESS) {
691 			struct ath_buf *tbf;
692 			struct ath_desc *tds;
693 
694 			if (list_is_last(&bf->list, &sc->rx.rxbuf)) {
695 				sc->rx.rxlink = NULL;
696 				break;
697 			}
698 
699 			tbf = list_entry(bf->list.next, struct ath_buf, list);
700 
701 			/*
702 			 * On some hardware the descriptor status words could
703 			 * get corrupted, including the done bit. Because of
704 			 * this, check if the next descriptor's done bit is
705 			 * set or not.
706 			 *
707 			 * If the next descriptor's done bit is set, the current
708 			 * descriptor has been corrupted. Force s/w to discard
709 			 * this descriptor and continue...
710 			 */
711 
712 			tds = tbf->bf_desc;
713 			retval = ath9k_hw_rxprocdesc(ah, tds, tbf->bf_daddr,
714 					     PA2DESC(sc, tds->ds_link), 0);
715 			if (retval == -EINPROGRESS) {
716 				break;
717 			}
718 		}
719 
720 		skb = bf->bf_mpdu;
721 		if (!skb)
722 			continue;
723 
724 		/*
725 		 * Synchronize the DMA transfer with CPU before
726 		 * 1. accessing the frame
727 		 * 2. requeueing the same buffer to h/w
728 		 */
729 		dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
730 				sc->rx.bufsize,
731 				DMA_FROM_DEVICE);
732 
733 		/*
734 		 * If we're asked to flush receive queue, directly
735 		 * chain it back at the queue without processing it.
736 		 */
737 		if (flush)
738 			goto requeue;
739 
740 		if (!ds->ds_rxstat.rs_datalen)
741 			goto requeue;
742 
743 		/* The status portion of the descriptor could get corrupted. */
744 		if (sc->rx.bufsize < ds->ds_rxstat.rs_datalen)
745 			goto requeue;
746 
747 		if (!ath_rx_prepare(skb, ds, &rx_status, &decrypt_error, sc))
748 			goto requeue;
749 
750 		/* Ensure we always have an skb to requeue once we are done
751 		 * processing the current buffer's skb */
752 		requeue_skb = ath_rxbuf_alloc(&sc->common, sc->rx.bufsize, GFP_ATOMIC);
753 
754 		/* If there is no memory we ignore the current RX'd frame,
755 		 * tell hardware it can give us a new frame using the old
756 		 * skb and put it at the tail of the sc->rx.rxbuf list for
757 		 * processing. */
758 		if (!requeue_skb)
759 			goto requeue;
760 
761 		/* Unmap the frame */
762 		dma_unmap_single(sc->dev, bf->bf_buf_addr,
763 				 sc->rx.bufsize,
764 				 DMA_FROM_DEVICE);
765 
766 		skb_put(skb, ds->ds_rxstat.rs_datalen);
767 
768 		/* see if any padding is done by the hw and remove it */
769 		hdr = (struct ieee80211_hdr *)skb->data;
770 		hdrlen = ieee80211_get_hdrlen_from_skb(skb);
771 		fc = hdr->frame_control;
772 
773 		/* The MAC header is padded to have 32-bit boundary if the
774 		 * packet payload is non-zero. The general calculation for
775 		 * padsize would take into account odd header lengths:
776 		 * padsize = (4 - hdrlen % 4) % 4; However, since only
777 		 * even-length headers are used, padding can only be 0 or 2
778 		 * bytes and we can optimize this a bit. In addition, we must
779 		 * not try to remove padding from short control frames that do
780 		 * not have payload. */
781 		padsize = hdrlen & 3;
782 		if (padsize && hdrlen >= 24) {
783 			memmove(skb->data + padsize, skb->data, hdrlen);
784 			skb_pull(skb, padsize);
785 		}
786 
787 		keyix = ds->ds_rxstat.rs_keyix;
788 
789 		if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error) {
790 			rx_status.flag |= RX_FLAG_DECRYPTED;
791 		} else if (ieee80211_has_protected(fc)
792 			   && !decrypt_error && skb->len >= hdrlen + 4) {
793 			keyix = skb->data[hdrlen + 3] >> 6;
794 
795 			if (test_bit(keyix, sc->keymap))
796 				rx_status.flag |= RX_FLAG_DECRYPTED;
797 		}
798 		if (ah->sw_mgmt_crypto &&
799 		    (rx_status.flag & RX_FLAG_DECRYPTED) &&
800 		    ieee80211_is_mgmt(fc)) {
801 			/* Use software decrypt for management frames. */
802 			rx_status.flag &= ~RX_FLAG_DECRYPTED;
803 		}
804 
805 		/* We will now give hardware our shiny new allocated skb */
806 		bf->bf_mpdu = requeue_skb;
807 		bf->bf_buf_addr = dma_map_single(sc->dev, requeue_skb->data,
808 					 sc->rx.bufsize,
809 					 DMA_FROM_DEVICE);
810 		if (unlikely(dma_mapping_error(sc->dev,
811 			  bf->bf_buf_addr))) {
812 			dev_kfree_skb_any(requeue_skb);
813 			bf->bf_mpdu = NULL;
814 			DPRINTF(sc, ATH_DBG_FATAL,
815 				"dma_mapping_error() on RX\n");
816 			ath_rx_send_to_mac80211(sc, skb, &rx_status);
817 			break;
818 		}
819 		bf->bf_dmacontext = bf->bf_buf_addr;
820 
821 		/*
822 		 * change the default rx antenna if rx diversity chooses the
823 		 * other antenna 3 times in a row.
824 		 */
825 		if (sc->rx.defant != ds->ds_rxstat.rs_antenna) {
826 			if (++sc->rx.rxotherant >= 3)
827 				ath_setdefantenna(sc, ds->ds_rxstat.rs_antenna);
828 		} else {
829 			sc->rx.rxotherant = 0;
830 		}
831 
832 		if (unlikely(sc->sc_flags & (SC_OP_WAIT_FOR_BEACON |
833 					     SC_OP_WAIT_FOR_CAB |
834 					     SC_OP_WAIT_FOR_PSPOLL_DATA)))
835 			ath_rx_ps(sc, skb);
836 
837 		ath_rx_send_to_mac80211(sc, skb, &rx_status);
838 
839 requeue:
840 		list_move_tail(&bf->list, &sc->rx.rxbuf);
841 		ath_rx_buf_link(sc, bf);
842 	} while (1);
843 
844 	spin_unlock_bh(&sc->rx.rxbuflock);
845 
846 	return 0;
847 #undef PA2DESC
848 }
849