drivers/net/wireless/iwlwifi/mvm/rx.c

   1 /******************************************************************************
   2  *
   3  * This file is provided under a dual BSD/GPLv2 license.  When using or
   4  * redistributing this file, you may do so under either license.
   5  *
   6  * GPL LICENSE SUMMARY
   7  *
   8  * Copyright(c) 2012 - 2013 Intel Corporation. All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of version 2 of the GNU General Public License as
  12  * published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110,
  22  * USA
  23  *
  24  * The full GNU General Public License is included in this distribution
  25  * in the file called LICENSE.GPL.
  26  *
  27  * Contact Information:
  28  *  Intel Linux Wireless <ilw@linux.intel.com>
  29  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
  30  *
  31  * BSD LICENSE
  32  *
  33  * Copyright(c) 2012 - 2013 Intel Corporation. All rights reserved.
  34  * All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  *
  40  *  * Redistributions of source code must retain the above copyright
  41  *    notice, this list of conditions and the following disclaimer.
  42  *  * Redistributions in binary form must reproduce the above copyright
  43  *    notice, this list of conditions and the following disclaimer in
  44  *    the documentation and/or other materials provided with the
  45  *    distribution.
  46  *  * Neither the name Intel Corporation nor the names of its
  47  *    contributors may be used to endorse or promote products derived
  48  *    from this software without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  51  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  52  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  53  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  54  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  55  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  56  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  57  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  58  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  59  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  60  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  61  *****************************************************************************/
  62 #include "iwl-trans.h"
  63
  64 #include "mvm.h"
  65 #include "fw-api.h"
  66
  67 /*
  68  * iwl_mvm_rx_rx_phy_cmd - REPLY_RX_PHY_CMD handler
  69  *
  70  * Copies the phy information in mvm->last_phy_info, it will be used when the
  71  * actual data will come from the fw in the next packet.
  72  */
  73 int iwl_mvm_rx_rx_phy_cmd(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
  74                           struct iwl_device_cmd *cmd)
  75 {
  76         struct iwl_rx_packet *pkt = rxb_addr(rxb);
  77
  78         memcpy(&mvm->last_phy_info, pkt->data, sizeof(mvm->last_phy_info));
  79         mvm->ampdu_ref++;
  80         return 0;
  81 }
  82
  83 /*
  84  * iwl_mvm_pass_packet_to_mac80211 - builds the packet for mac80211
  85  *
  86  * Adds the rxb to a new skb and give it to mac80211
  87  */
  88 static void iwl_mvm_pass_packet_to_mac80211(struct iwl_mvm *mvm,
  89                                             struct ieee80211_hdr *hdr, u16 len,
  90                                             u32 ampdu_status,
  91                                             struct iwl_rx_cmd_buffer *rxb,
  92                                             struct ieee80211_rx_status *stats)
  93 {
  94         struct sk_buff *skb;
  95         unsigned int hdrlen, fraglen;
  96
  97         /* Dont use dev_alloc_skb(), we'll have enough headroom once
  98          * ieee80211_hdr pulled.
  99          */
 100         skb = alloc_skb(128, GFP_ATOMIC);
 101         if (!skb) {
 102                 IWL_ERR(mvm, "alloc_skb failed\n");
 103                 return;
 104         }
 105         /* If frame is small enough to fit in skb->head, pull it completely.
 106          * If not, only pull ieee80211_hdr so that splice() or TCP coalesce
 107          * are more efficient.
 108          */
 109         hdrlen = (len <= skb_tailroom(skb)) ? len : sizeof(*hdr);
 110
 111         memcpy(skb_put(skb, hdrlen), hdr, hdrlen);
 112         fraglen = len - hdrlen;
 113
 114         if (fraglen) {
 115                 int offset = (void *)hdr + hdrlen -
 116                              rxb_addr(rxb) + rxb_offset(rxb);
 117
 118                 skb_add_rx_frag(skb, 0, rxb_steal_page(rxb), offset,
 119                                 fraglen, rxb->truesize);
 120         }
 121
 122         memcpy(IEEE80211_SKB_RXCB(skb), stats, sizeof(*stats));
 123
 124         ieee80211_rx(mvm->hw, skb);
 125 }
 126
 127 /*
 128  * iwl_mvm_calc_rssi - calculate the rssi in dBm
 129  * @phy_info: the phy information for the coming packet
 130  */
 131 static int iwl_mvm_calc_rssi(struct iwl_mvm *mvm,
 132                              struct iwl_rx_phy_info *phy_info)
 133 {
 134         u32 rssi_a, rssi_b, rssi_c, max_rssi, agc_db;
 135         u32 val;
 136
 137         /* Find max rssi among 3 possible receivers.
 138          * These values are measured by the Digital Signal Processor (DSP).
 139          * They should stay fairly constant even as the signal strength varies,
 140          * if the radio's Automatic Gain Control (AGC) is working right.
 141          * AGC value (see below) will provide the "interesting" info.
 142          */
 143         val = le32_to_cpu(phy_info->non_cfg_phy[IWL_RX_INFO_RSSI_AB_IDX]);
 144         rssi_a = (val & IWL_OFDM_RSSI_INBAND_A_MSK) >> IWL_OFDM_RSSI_A_POS;
 145         rssi_b = (val & IWL_OFDM_RSSI_INBAND_B_MSK) >> IWL_OFDM_RSSI_B_POS;
 146         val = le32_to_cpu(phy_info->non_cfg_phy[IWL_RX_INFO_RSSI_C_IDX]);
 147         rssi_c = (val & IWL_OFDM_RSSI_INBAND_C_MSK) >> IWL_OFDM_RSSI_C_POS;
 148
 149         val = le32_to_cpu(phy_info->non_cfg_phy[IWL_RX_INFO_AGC_IDX]);
 150         agc_db = (val & IWL_OFDM_AGC_DB_MSK) >> IWL_OFDM_AGC_DB_POS;
 151
 152         max_rssi = max_t(u32, rssi_a, rssi_b);
 153         max_rssi = max_t(u32, max_rssi, rssi_c);
 154
 155         IWL_DEBUG_STATS(mvm, "Rssi In A %d B %d C %d Max %d AGC dB %d\n",
 156                         rssi_a, rssi_b, rssi_c, max_rssi, agc_db);
 157
 158         /* dBm = max_rssi dB - agc dB - constant.
 159          * Higher AGC (higher radio gain) means lower signal. */
 160         return max_rssi - agc_db - IWL_RSSI_OFFSET;
 161 }
 162
 163 /*
 164  * iwl_mvm_set_mac80211_rx_flag - translate fw status to mac80211 format
 165  * @mvm: the mvm object
 166  * @hdr: 80211 header
 167  * @stats: status in mac80211's format
 168  * @rx_pkt_status: status coming from fw
 169  *
 170  * returns non 0 value if the packet should be dropped
 171  */
 172 static u32 iwl_mvm_set_mac80211_rx_flag(struct iwl_mvm *mvm,
 173                                         struct ieee80211_hdr *hdr,
 174                                         struct ieee80211_rx_status *stats,
 175                                         u32 rx_pkt_status)
 176 {
 177         if (!ieee80211_has_protected(hdr->frame_control) ||
 178             (rx_pkt_status & RX_MPDU_RES_STATUS_SEC_ENC_MSK) ==
 179                              RX_MPDU_RES_STATUS_SEC_NO_ENC)
 180                 return 0;
 181
 182         /* packet was encrypted with unknown alg */
 183         if ((rx_pkt_status & RX_MPDU_RES_STATUS_SEC_ENC_MSK) ==
 184                                         RX_MPDU_RES_STATUS_SEC_ENC_ERR)
 185                 return 0;
 186
 187         switch (rx_pkt_status & RX_MPDU_RES_STATUS_SEC_ENC_MSK) {
 188         case RX_MPDU_RES_STATUS_SEC_CCM_ENC:
 189                 /* alg is CCM: check MIC only */
 190                 if (!(rx_pkt_status & RX_MPDU_RES_STATUS_MIC_OK))
 191                         return -1;
 192
 193                 stats->flag |= RX_FLAG_DECRYPTED;
 194                 IWL_DEBUG_WEP(mvm, "hw decrypted CCMP successfully\n");
 195                 return 0;
 196
 197         case RX_MPDU_RES_STATUS_SEC_TKIP_ENC:
 198                 /* Don't drop the frame and decrypt it in SW */
 199                 if (!(rx_pkt_status & RX_MPDU_RES_STATUS_TTAK_OK))
 200                         return 0;
 201                 /* fall through if TTAK OK */
 202
 203         case RX_MPDU_RES_STATUS_SEC_WEP_ENC:
 204                 if (!(rx_pkt_status & RX_MPDU_RES_STATUS_ICV_OK))
 205                         return -1;
 206
 207                 stats->flag |= RX_FLAG_DECRYPTED;
 208                 return 0;
 209
 210         default:
 211                 IWL_ERR(mvm, "Unhandled alg: 0x%x\n", rx_pkt_status);
 212         }
 213
 214         return 0;
 215 }
 216
 217 /*
 218  * iwl_mvm_rx_rx_mpdu - REPLY_RX_MPDU_CMD handler
 219  *
 220  * Handles the actual data of the Rx packet from the fw
 221  */
 222 int iwl_mvm_rx_rx_mpdu(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
 223                        struct iwl_device_cmd *cmd)
 224 {
 225         struct ieee80211_hdr *hdr;
 226         struct ieee80211_rx_status rx_status = {};
 227         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 228         struct iwl_rx_phy_info *phy_info;
 229         struct iwl_rx_mpdu_res_start *rx_res;
 230         u32 len;
 231         u32 ampdu_status;
 232         u32 rate_n_flags;
 233         u32 rx_pkt_status;
 234
 235         phy_info = &mvm->last_phy_info;
 236         rx_res = (struct iwl_rx_mpdu_res_start *)pkt->data;
 237         hdr = (struct ieee80211_hdr *)(pkt->data + sizeof(*rx_res));
 238         len = le16_to_cpu(rx_res->byte_count);
 239         rx_pkt_status = le32_to_cpup((__le32 *)
 240                 (pkt->data + sizeof(*rx_res) + len));
 241
 242         memset(&rx_status, 0, sizeof(rx_status));
 243
 244         /*
 245          * drop the packet if it has failed being decrypted by HW
 246          */
 247         if (iwl_mvm_set_mac80211_rx_flag(mvm, hdr, &rx_status, rx_pkt_status)) {
 248                 IWL_DEBUG_DROP(mvm, "Bad decryption results 0x%08x\n",
 249                                rx_pkt_status);
 250                 return 0;
 251         }
 252
 253         if ((unlikely(phy_info->cfg_phy_cnt > 20))) {
 254                 IWL_DEBUG_DROP(mvm, "dsp size out of range [0,20]: %d\n",
 255                                phy_info->cfg_phy_cnt);
 256                 return 0;
 257         }
 258
 259         if (!(rx_pkt_status & RX_MPDU_RES_STATUS_CRC_OK) ||
 260             !(rx_pkt_status & RX_MPDU_RES_STATUS_OVERRUN_OK)) {
 261                 IWL_DEBUG_RX(mvm, "Bad CRC or FIFO: 0x%08X.\n", rx_pkt_status);
 262                 return 0;
 263         }
 264
 265         /* This will be used in several places later */
 266         rate_n_flags = le32_to_cpu(phy_info->rate_n_flags);
 267
 268         /* rx_status carries information about the packet to mac80211 */
 269         rx_status.mactime = le64_to_cpu(phy_info->timestamp);
 270         rx_status.band =
 271                 (phy_info->phy_flags & cpu_to_le16(RX_RES_PHY_FLAGS_BAND_24)) ?
 272                                 IEEE80211_BAND_2GHZ : IEEE80211_BAND_5GHZ;
 273         rx_status.freq =
 274                 ieee80211_channel_to_frequency(le16_to_cpu(phy_info->channel),
 275                                                rx_status.band);
 276         /*
 277          * TSF as indicated by the fw is at INA time, but mac80211 expects the
 278          * TSF at the beginning of the MPDU.
 279          */
 280         /*rx_status.flag |= RX_FLAG_MACTIME_MPDU;*/
 281
 282         /* Find max signal strength (dBm) among 3 antenna/receiver chains */
 283         rx_status.signal = iwl_mvm_calc_rssi(mvm, phy_info);
 284
 285         IWL_DEBUG_STATS_LIMIT(mvm, "Rssi %d, TSF %llu\n", rx_status.signal,
 286                               (unsigned long long)rx_status.mactime);
 287
 288         /*
 289          * "antenna number"
 290          *
 291          * It seems that the antenna field in the phy flags value
 292          * is actually a bit field. This is undefined by radiotap,
 293          * it wants an actual antenna number but I always get "7"
 294          * for most legacy frames I receive indicating that the
 295          * same frame was received on all three RX chains.
 296          *
 297          * I think this field should be removed in favor of a
 298          * new 802.11n radiotap field "RX chains" that is defined
 299          * as a bitmask.
 300          */
 301         rx_status.antenna = (le16_to_cpu(phy_info->phy_flags) &
 302                                 RX_RES_PHY_FLAGS_ANTENNA)
 303                                 >> RX_RES_PHY_FLAGS_ANTENNA_POS;
 304
 305         /* set the preamble flag if appropriate */
 306         if (phy_info->phy_flags & cpu_to_le16(RX_RES_PHY_FLAGS_SHORT_PREAMBLE))
 307                 rx_status.flag |= RX_FLAG_SHORTPRE;
 308
 309         if (phy_info->phy_flags & cpu_to_le16(RX_RES_PHY_FLAGS_AGG)) {
 310                 /*
 311                  * We know which subframes of an A-MPDU belong
 312                  * together since we get a single PHY response
 313                  * from the firmware for all of them
 314                  */
 315                 rx_status.flag |= RX_FLAG_AMPDU_DETAILS;
 316                 rx_status.ampdu_reference = mvm->ampdu_ref;
 317         }
 318
 319         /* Set up the HT phy flags */
 320         switch (rate_n_flags & RATE_MCS_CHAN_WIDTH_MSK) {
 321         case RATE_MCS_CHAN_WIDTH_20:
 322                 break;
 323         case RATE_MCS_CHAN_WIDTH_40:
 324                 rx_status.flag |= RX_FLAG_40MHZ;
 325                 break;
 326         case RATE_MCS_CHAN_WIDTH_80:
 327                 rx_status.flag |= RX_FLAG_80MHZ;
 328                 break;
 329         case RATE_MCS_CHAN_WIDTH_160:
 330                 rx_status.flag |= RX_FLAG_160MHZ;
 331                 break;
 332         }
 333         if (rate_n_flags & RATE_MCS_SGI_MSK)
 334                 rx_status.flag |= RX_FLAG_SHORT_GI;
 335         if (rate_n_flags & RATE_HT_MCS_GF_MSK)
 336                 rx_status.flag |= RX_FLAG_HT_GF;
 337         if (rate_n_flags & RATE_MCS_HT_MSK) {
 338                 rx_status.flag |= RX_FLAG_HT;
 339                 rx_status.rate_idx = rate_n_flags & RATE_HT_MCS_INDEX_MSK;
 340         } else if (rate_n_flags & RATE_MCS_VHT_MSK) {
 341                 rx_status.vht_nss =
 342                         ((rate_n_flags & RATE_VHT_MCS_NSS_MSK) >>
 343                                                 RATE_VHT_MCS_NSS_POS) + 1;
 344                 rx_status.rate_idx = rate_n_flags & RATE_VHT_MCS_RATE_CODE_MSK;
 345                 rx_status.flag |= RX_FLAG_VHT;
 346         } else {
 347                 rx_status.rate_idx =
 348                         iwl_mvm_legacy_rate_to_mac80211_idx(rate_n_flags,
 349                                                             rx_status.band);
 350         }
 351
 352         iwl_mvm_pass_packet_to_mac80211(mvm, hdr, len, ampdu_status,
 353                                         rxb, &rx_status);
 354         return 0;
 355 }