1 /*
2  * Copyright (c) 2009-2011 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 /*
18  * Module for common driver code between ath9k and ath9k_htc
19  */
20 
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 
24 #include "common.h"
25 
26 MODULE_AUTHOR("Atheros Communications");
27 MODULE_DESCRIPTION("Shared library for Atheros wireless 802.11n LAN cards.");
28 MODULE_LICENSE("Dual BSD/GPL");
29 
30 /* Assumes you've already done the endian to CPU conversion */
31 bool ath9k_cmn_rx_accept(struct ath_common *common,
32 			 struct ieee80211_hdr *hdr,
33 			 struct ieee80211_rx_status *rxs,
34 			 struct ath_rx_status *rx_stats,
35 			 bool *decrypt_error,
36 			 unsigned int rxfilter)
37 {
38 	struct ath_hw *ah = common->ah;
39 	bool is_mc, is_valid_tkip, strip_mic, mic_error;
40 	__le16 fc;
41 
42 	fc = hdr->frame_control;
43 
44 	is_mc = !!is_multicast_ether_addr(hdr->addr1);
45 	is_valid_tkip = rx_stats->rs_keyix != ATH9K_RXKEYIX_INVALID &&
46 		test_bit(rx_stats->rs_keyix, common->tkip_keymap);
47 	strip_mic = is_valid_tkip && ieee80211_is_data(fc) &&
48 		ieee80211_has_protected(fc) &&
49 		!(rx_stats->rs_status &
50 		(ATH9K_RXERR_DECRYPT | ATH9K_RXERR_CRC | ATH9K_RXERR_MIC |
51 		 ATH9K_RXERR_KEYMISS));
52 
53 	/*
54 	 * Key miss events are only relevant for pairwise keys where the
55 	 * descriptor does contain a valid key index. This has been observed
56 	 * mostly with CCMP encryption.
57 	 */
58 	if (rx_stats->rs_keyix == ATH9K_RXKEYIX_INVALID ||
59 	    !test_bit(rx_stats->rs_keyix, common->ccmp_keymap))
60 		rx_stats->rs_status &= ~ATH9K_RXERR_KEYMISS;
61 
62 	mic_error = is_valid_tkip && !ieee80211_is_ctl(fc) &&
63 		!ieee80211_has_morefrags(fc) &&
64 		!(le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG) &&
65 		(rx_stats->rs_status & ATH9K_RXERR_MIC);
66 
67 	/*
68 	 * The rx_stats->rs_status will not be set until the end of the
69 	 * chained descriptors so it can be ignored if rs_more is set. The
70 	 * rs_more will be false at the last element of the chained
71 	 * descriptors.
72 	 */
73 	if (rx_stats->rs_status != 0) {
74 		u8 status_mask;
75 
76 		if (rx_stats->rs_status & ATH9K_RXERR_CRC) {
77 			rxs->flag |= RX_FLAG_FAILED_FCS_CRC;
78 			mic_error = false;
79 		}
80 
81 		if ((rx_stats->rs_status & ATH9K_RXERR_DECRYPT) ||
82 		    (!is_mc && (rx_stats->rs_status & ATH9K_RXERR_KEYMISS))) {
83 			*decrypt_error = true;
84 			mic_error = false;
85 		}
86 
87 
88 		/*
89 		 * Reject error frames with the exception of
90 		 * decryption and MIC failures. For monitor mode,
91 		 * we also ignore the CRC error.
92 		 */
93 		status_mask = ATH9K_RXERR_DECRYPT | ATH9K_RXERR_MIC |
94 			      ATH9K_RXERR_KEYMISS;
95 
96 		if (ah->is_monitoring && (rxfilter & FIF_FCSFAIL))
97 			status_mask |= ATH9K_RXERR_CRC;
98 
99 		if (rx_stats->rs_status & ~status_mask)
100 			return false;
101 	}
102 
103 	/*
104 	 * For unicast frames the MIC error bit can have false positives,
105 	 * so all MIC error reports need to be validated in software.
106 	 * False negatives are not common, so skip software verification
107 	 * if the hardware considers the MIC valid.
108 	 */
109 	if (strip_mic)
110 		rxs->flag |= RX_FLAG_MMIC_STRIPPED;
111 	else if (is_mc && mic_error)
112 		rxs->flag |= RX_FLAG_MMIC_ERROR;
113 
114 	return true;
115 }
116 EXPORT_SYMBOL(ath9k_cmn_rx_accept);
117 
118 void ath9k_cmn_rx_skb_postprocess(struct ath_common *common,
119 				  struct sk_buff *skb,
120 				  struct ath_rx_status *rx_stats,
121 				  struct ieee80211_rx_status *rxs,
122 				  bool decrypt_error)
123 {
124 	struct ath_hw *ah = common->ah;
125 	struct ieee80211_hdr *hdr;
126 	int hdrlen, padpos, padsize;
127 	u8 keyix;
128 	__le16 fc;
129 
130 	/* see if any padding is done by the hw and remove it */
131 	hdr = (struct ieee80211_hdr *) skb->data;
132 	hdrlen = ieee80211_get_hdrlen_from_skb(skb);
133 	fc = hdr->frame_control;
134 	padpos = ieee80211_hdrlen(fc);
135 
136 	/* The MAC header is padded to have 32-bit boundary if the
137 	 * packet payload is non-zero. The general calculation for
138 	 * padsize would take into account odd header lengths:
139 	 * padsize = (4 - padpos % 4) % 4; However, since only
140 	 * even-length headers are used, padding can only be 0 or 2
141 	 * bytes and we can optimize this a bit. In addition, we must
142 	 * not try to remove padding from short control frames that do
143 	 * not have payload. */
144 	padsize = padpos & 3;
145 	if (padsize && skb->len>=padpos+padsize+FCS_LEN) {
146 		memmove(skb->data + padsize, skb->data, padpos);
147 		skb_pull(skb, padsize);
148 	}
149 
150 	keyix = rx_stats->rs_keyix;
151 
152 	if (!(keyix == ATH9K_RXKEYIX_INVALID) && !decrypt_error &&
153 	    ieee80211_has_protected(fc)) {
154 		rxs->flag |= RX_FLAG_DECRYPTED;
155 	} else if (ieee80211_has_protected(fc)
156 		   && !decrypt_error && skb->len >= hdrlen + 4) {
157 		keyix = skb->data[hdrlen + 3] >> 6;
158 
159 		if (test_bit(keyix, common->keymap))
160 			rxs->flag |= RX_FLAG_DECRYPTED;
161 	}
162 	if (ah->sw_mgmt_crypto_rx &&
163 	    (rxs->flag & RX_FLAG_DECRYPTED) &&
164 	    ieee80211_is_mgmt(fc))
165 		/* Use software decrypt for management frames. */
166 		rxs->flag &= ~RX_FLAG_DECRYPTED;
167 }
168 EXPORT_SYMBOL(ath9k_cmn_rx_skb_postprocess);
169 
170 int ath9k_cmn_process_rate(struct ath_common *common,
171 			   struct ieee80211_hw *hw,
172 			   struct ath_rx_status *rx_stats,
173 			   struct ieee80211_rx_status *rxs)
174 {
175 	struct ieee80211_supported_band *sband;
176 	enum nl80211_band band;
177 	unsigned int i = 0;
178 	struct ath_hw *ah = common->ah;
179 
180 	band = ah->curchan->chan->band;
181 	sband = hw->wiphy->bands[band];
182 
183 	if (IS_CHAN_QUARTER_RATE(ah->curchan))
184 		rxs->bw = RATE_INFO_BW_5;
185 	else if (IS_CHAN_HALF_RATE(ah->curchan))
186 		rxs->bw = RATE_INFO_BW_10;
187 
188 	if (rx_stats->rs_rate & 0x80) {
189 		/* HT rate */
190 		rxs->encoding = RX_ENC_HT;
191 		rxs->enc_flags |= rx_stats->enc_flags;
192 		rxs->bw = rx_stats->bw;
193 		rxs->rate_idx = rx_stats->rs_rate & 0x7f;
194 		return 0;
195 	}
196 
197 	for (i = 0; i < sband->n_bitrates; i++) {
198 		if (sband->bitrates[i].hw_value == rx_stats->rs_rate) {
199 			rxs->rate_idx = i;
200 			return 0;
201 		}
202 		if (sband->bitrates[i].hw_value_short == rx_stats->rs_rate) {
203 			rxs->enc_flags |= RX_ENC_FLAG_SHORTPRE;
204 			rxs->rate_idx = i;
205 			return 0;
206 		}
207 	}
208 
209 	return -EINVAL;
210 }
211 EXPORT_SYMBOL(ath9k_cmn_process_rate);
212 
213 void ath9k_cmn_process_rssi(struct ath_common *common,
214 			    struct ieee80211_hw *hw,
215 			    struct ath_rx_status *rx_stats,
216 			    struct ieee80211_rx_status *rxs)
217 {
218 	struct ath_hw *ah = common->ah;
219 	int last_rssi;
220 	int rssi = rx_stats->rs_rssi;
221 	int i, j;
222 
223 	/*
224 	 * RSSI is not available for subframes in an A-MPDU.
225 	 */
226 	if (rx_stats->rs_moreaggr) {
227 		rxs->flag |= RX_FLAG_NO_SIGNAL_VAL;
228 		return;
229 	}
230 
231 	/*
232 	 * Check if the RSSI for the last subframe in an A-MPDU
233 	 * or an unaggregated frame is valid.
234 	 */
235 	if (rx_stats->rs_rssi == ATH9K_RSSI_BAD) {
236 		rxs->flag |= RX_FLAG_NO_SIGNAL_VAL;
237 		return;
238 	}
239 
240 	for (i = 0, j = 0; i < ARRAY_SIZE(rx_stats->rs_rssi_ctl); i++) {
241 		s8 rssi;
242 
243 		if (!(ah->rxchainmask & BIT(i)))
244 			continue;
245 
246 		rssi = rx_stats->rs_rssi_ctl[i];
247 		if (rssi != ATH9K_RSSI_BAD) {
248 		    rxs->chains |= BIT(j);
249 		    rxs->chain_signal[j] = ah->noise + rssi;
250 		}
251 		j++;
252 	}
253 
254 	/*
255 	 * Update Beacon RSSI, this is used by ANI.
256 	 */
257 	if (rx_stats->is_mybeacon &&
258 	    ((ah->opmode == NL80211_IFTYPE_STATION) ||
259 	     (ah->opmode == NL80211_IFTYPE_ADHOC))) {
260 		ATH_RSSI_LPF(common->last_rssi, rx_stats->rs_rssi);
261 		last_rssi = common->last_rssi;
262 
263 		if (likely(last_rssi != ATH_RSSI_DUMMY_MARKER))
264 			rssi = ATH_EP_RND(last_rssi, ATH_RSSI_EP_MULTIPLIER);
265 		if (rssi < 0)
266 			rssi = 0;
267 
268 		ah->stats.avgbrssi = rssi;
269 	}
270 
271 	rxs->signal = ah->noise + rx_stats->rs_rssi;
272 }
273 EXPORT_SYMBOL(ath9k_cmn_process_rssi);
274 
275 int ath9k_cmn_get_hw_crypto_keytype(struct sk_buff *skb)
276 {
277 	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
278 
279 	if (tx_info->control.hw_key) {
280 		switch (tx_info->control.hw_key->cipher) {
281 		case WLAN_CIPHER_SUITE_WEP40:
282 		case WLAN_CIPHER_SUITE_WEP104:
283 			return ATH9K_KEY_TYPE_WEP;
284 		case WLAN_CIPHER_SUITE_TKIP:
285 			return ATH9K_KEY_TYPE_TKIP;
286 		case WLAN_CIPHER_SUITE_CCMP:
287 			return ATH9K_KEY_TYPE_AES;
288 		default:
289 			break;
290 		}
291 	}
292 
293 	return ATH9K_KEY_TYPE_CLEAR;
294 }
295 EXPORT_SYMBOL(ath9k_cmn_get_hw_crypto_keytype);
296 
297 /*
298  * Update internal channel flags.
299  */
300 static void ath9k_cmn_update_ichannel(struct ath9k_channel *ichan,
301 				      struct cfg80211_chan_def *chandef)
302 {
303 	struct ieee80211_channel *chan = chandef->chan;
304 	u16 flags = 0;
305 
306 	ichan->channel = chan->center_freq;
307 	ichan->chan = chan;
308 
309 	if (chan->band == NL80211_BAND_5GHZ)
310 		flags |= CHANNEL_5GHZ;
311 
312 	switch (chandef->width) {
313 	case NL80211_CHAN_WIDTH_5:
314 		flags |= CHANNEL_QUARTER;
315 		break;
316 	case NL80211_CHAN_WIDTH_10:
317 		flags |= CHANNEL_HALF;
318 		break;
319 	case NL80211_CHAN_WIDTH_20_NOHT:
320 		break;
321 	case NL80211_CHAN_WIDTH_20:
322 		flags |= CHANNEL_HT;
323 		break;
324 	case NL80211_CHAN_WIDTH_40:
325 		if (chandef->center_freq1 > chandef->chan->center_freq)
326 			flags |= CHANNEL_HT40PLUS | CHANNEL_HT;
327 		else
328 			flags |= CHANNEL_HT40MINUS | CHANNEL_HT;
329 		break;
330 	default:
331 		WARN_ON(1);
332 	}
333 
334 	ichan->channelFlags = flags;
335 }
336 
337 /*
338  * Get the internal channel reference.
339  */
340 struct ath9k_channel *ath9k_cmn_get_channel(struct ieee80211_hw *hw,
341 					    struct ath_hw *ah,
342 					    struct cfg80211_chan_def *chandef)
343 {
344 	struct ieee80211_channel *curchan = chandef->chan;
345 	struct ath9k_channel *channel;
346 
347 	channel = &ah->channels[curchan->hw_value];
348 	ath9k_cmn_update_ichannel(channel, chandef);
349 
350 	return channel;
351 }
352 EXPORT_SYMBOL(ath9k_cmn_get_channel);
353 
354 int ath9k_cmn_count_streams(unsigned int chainmask, int max)
355 {
356 	int streams = 0;
357 
358 	do {
359 		if (++streams == max)
360 			break;
361 	} while ((chainmask = chainmask & (chainmask - 1)));
362 
363 	return streams;
364 }
365 EXPORT_SYMBOL(ath9k_cmn_count_streams);
366 
367 void ath9k_cmn_update_txpow(struct ath_hw *ah, u16 cur_txpow,
368 			    u16 new_txpow, u16 *txpower)
369 {
370 	struct ath_regulatory *reg = ath9k_hw_regulatory(ah);
371 
372 	if (ah->curchan && reg->power_limit != new_txpow)
373 		ath9k_hw_set_txpowerlimit(ah, new_txpow, false);
374 
375 	/* read back in case value is clamped */
376 	*txpower = reg->max_power_level;
377 }
378 EXPORT_SYMBOL(ath9k_cmn_update_txpow);
379 
380 void ath9k_cmn_init_crypto(struct ath_hw *ah)
381 {
382 	struct ath_common *common = ath9k_hw_common(ah);
383 	int i = 0;
384 
385 	/* Get the hardware key cache size. */
386 	common->keymax = AR_KEYTABLE_SIZE;
387 
388 	/*
389 	 * Check whether the separate key cache entries
390 	 * are required to handle both tx+rx MIC keys.
391 	 * With split mic keys the number of stations is limited
392 	 * to 27 otherwise 59.
393 	 */
394 	if (ah->misc_mode & AR_PCU_MIC_NEW_LOC_ENA)
395 		common->crypt_caps |= ATH_CRYPT_CAP_MIC_COMBINED;
396 
397 	/*
398 	 * Reset the key cache since some parts do not
399 	 * reset the contents on initial power up.
400 	 */
401 	for (i = 0; i < common->keymax; i++)
402 		ath_hw_keyreset(common, (u16) i);
403 }
404 EXPORT_SYMBOL(ath9k_cmn_init_crypto);
405 
406 static int __init ath9k_cmn_init(void)
407 {
408 	return 0;
409 }
410 module_init(ath9k_cmn_init);
411 
412 static void __exit ath9k_cmn_exit(void)
413 {
414 	return;
415 }
416 module_exit(ath9k_cmn_exit);
417