drivers/net/wireless/ath/ath9k/common.c

   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);