drivers/net/wireless/ath/carl9170/rx.c

   1 /*
   2  * Atheros CARL9170 driver
   3  *
   4  * 802.11 & command trap routines
   5  *
   6  * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
   7  * Copyright 2009, 2010, Christian Lamparter <chunkeey@googlemail.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU 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; see the file COPYING.  If not, see
  21  * http://www.gnu.org/licenses/.
  22  *
  23  * This file incorporates work covered by the following copyright and
  24  * permission notice:
  25  *    Copyright (c) 2007-2008 Atheros Communications, Inc.
  26  *
  27  *    Permission to use, copy, modify, and/or distribute this software for any
  28  *    purpose with or without fee is hereby granted, provided that the above
  29  *    copyright notice and this permission notice appear in all copies.
  30  *
  31  *    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  32  *    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  33  *    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  34  *    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  35  *    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  36  *    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  37  *    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  38  */
  39
  40 #include <linux/init.h>
  41 #include <linux/slab.h>
  42 #include <linux/module.h>
  43 #include <linux/etherdevice.h>
  44 #include <linux/crc32.h>
  45 #include <net/mac80211.h>
  46 #include "carl9170.h"
  47 #include "hw.h"
  48 #include "cmd.h"
  49
  50 static void carl9170_dbg_message(struct ar9170 *ar, const char *buf, u32 len)
  51 {
  52         bool restart = false;
  53         enum carl9170_restart_reasons reason = CARL9170_RR_NO_REASON;
  54
  55         if (len > 3) {
  56                 if (memcmp(buf, CARL9170_ERR_MAGIC, 3) == 0) {
  57                         ar->fw.err_counter++;
  58                         if (ar->fw.err_counter > 3) {
  59                                 restart = true;
  60                                 reason = CARL9170_RR_TOO_MANY_FIRMWARE_ERRORS;
  61                         }
  62                 }
  63
  64                 if (memcmp(buf, CARL9170_BUG_MAGIC, 3) == 0) {
  65                         ar->fw.bug_counter++;
  66                         restart = true;
  67                         reason = CARL9170_RR_FATAL_FIRMWARE_ERROR;
  68                 }
  69         }
  70
  71         wiphy_info(ar->hw->wiphy, "FW: %.*s\n", len, buf);
  72
  73         if (restart)
  74                 carl9170_restart(ar, reason);
  75 }
  76
  77 static void carl9170_handle_ps(struct ar9170 *ar, struct carl9170_rsp *rsp)
  78 {
  79         u32 ps;
  80         bool new_ps;
  81
  82         ps = le32_to_cpu(rsp->psm.state);
  83
  84         new_ps = (ps & CARL9170_PSM_COUNTER) != CARL9170_PSM_WAKE;
  85         if (ar->ps.state != new_ps) {
  86                 if (!new_ps) {
  87                         ar->ps.sleep_ms = jiffies_to_msecs(jiffies -
  88                                 ar->ps.last_action);
  89                 }
  90
  91                 ar->ps.last_action = jiffies;
  92
  93                 ar->ps.state = new_ps;
  94         }
  95 }
  96
  97 static int carl9170_check_sequence(struct ar9170 *ar, unsigned int seq)
  98 {
  99         if (ar->cmd_seq < -1)
 100                 return 0;
 101
 102         /*
 103          * Initialize Counter
 104          */
 105         if (ar->cmd_seq < 0)
 106                 ar->cmd_seq = seq;
 107
 108         /*
 109          * The sequence is strictly monotonic increasing and it never skips!
 110          *
 111          * Therefore we can safely assume that whenever we received an
 112          * unexpected sequence we have lost some valuable data.
 113          */
 114         if (seq != ar->cmd_seq) {
 115                 int count;
 116
 117                 count = (seq - ar->cmd_seq) % ar->fw.cmd_bufs;
 118
 119                 wiphy_err(ar->hw->wiphy, "lost %d command responses/traps! "
 120                           "w:%d g:%d\n", count, ar->cmd_seq, seq);
 121
 122                 carl9170_restart(ar, CARL9170_RR_LOST_RSP);
 123                 return -EIO;
 124         }
 125
 126         ar->cmd_seq = (ar->cmd_seq + 1) % ar->fw.cmd_bufs;
 127         return 0;
 128 }
 129
 130 static void carl9170_cmd_callback(struct ar9170 *ar, u32 len, void *buffer)
 131 {
 132         /*
 133          * Some commands may have a variable response length
 134          * and we cannot predict the correct length in advance.
 135          * So we only check if we provided enough space for the data.
 136          */
 137         if (unlikely(ar->readlen != (len - 4))) {
 138                 dev_warn(&ar->udev->dev, "received invalid command response:"
 139                          "got %d, instead of %d\n", len - 4, ar->readlen);
 140                 print_hex_dump_bytes("carl9170 cmd:", DUMP_PREFIX_OFFSET,
 141                         ar->cmd_buf, (ar->cmd.hdr.len + 4) & 0x3f);
 142                 print_hex_dump_bytes("carl9170 rsp:", DUMP_PREFIX_OFFSET,
 143                         buffer, len);
 144                 /*
 145                  * Do not complete. The command times out,
 146                  * and we get a stack trace from there.
 147                  */
 148                 carl9170_restart(ar, CARL9170_RR_INVALID_RSP);
 149         }
 150
 151         spin_lock(&ar->cmd_lock);
 152         if (ar->readbuf) {
 153                 if (len >= 4)
 154                         memcpy(ar->readbuf, buffer + 4, len - 4);
 155
 156                 ar->readbuf = NULL;
 157         }
 158         complete(&ar->cmd_wait);
 159         spin_unlock(&ar->cmd_lock);
 160 }
 161
 162 void carl9170_handle_command_response(struct ar9170 *ar, void *buf, u32 len)
 163 {
 164         struct carl9170_rsp *cmd = (void *) buf;
 165         struct ieee80211_vif *vif;
 166
 167         if (carl9170_check_sequence(ar, cmd->hdr.seq))
 168                 return;
 169
 170         if ((cmd->hdr.cmd & CARL9170_RSP_FLAG) != CARL9170_RSP_FLAG) {
 171                 if (!(cmd->hdr.cmd & CARL9170_CMD_ASYNC_FLAG))
 172                         carl9170_cmd_callback(ar, len, buf);
 173
 174                 return;
 175         }
 176
 177         if (unlikely(cmd->hdr.len != (len - 4))) {
 178                 if (net_ratelimit()) {
 179                         wiphy_err(ar->hw->wiphy, "FW: received over-/under"
 180                                 "sized event %x (%d, but should be %d).\n",
 181                                cmd->hdr.cmd, cmd->hdr.len, len - 4);
 182
 183                         print_hex_dump_bytes("dump:", DUMP_PREFIX_NONE,
 184                                              buf, len);
 185                 }
 186
 187                 return;
 188         }
 189
 190         /* hardware event handlers */
 191         switch (cmd->hdr.cmd) {
 192         case CARL9170_RSP_PRETBTT:
 193                 /* pre-TBTT event */
 194                 rcu_read_lock();
 195                 vif = carl9170_get_main_vif(ar);
 196
 197                 if (!vif) {
 198                         rcu_read_unlock();
 199                         break;
 200                 }
 201
 202                 switch (vif->type) {
 203                 case NL80211_IFTYPE_STATION:
 204                         carl9170_handle_ps(ar, cmd);
 205                         break;
 206
 207                 case NL80211_IFTYPE_AP:
 208                 case NL80211_IFTYPE_ADHOC:
 209                         carl9170_update_beacon(ar, true);
 210                         break;
 211
 212                 default:
 213                         break;
 214                 }
 215                 rcu_read_unlock();
 216
 217                 break;
 218
 219
 220         case CARL9170_RSP_TXCOMP:
 221                 /* TX status notification */
 222                 carl9170_tx_process_status(ar, cmd);
 223                 break;
 224
 225         case CARL9170_RSP_BEACON_CONFIG:
 226                 /*
 227                  * (IBSS) beacon send notification
 228                  * bytes: 04 c2 XX YY B4 B3 B2 B1
 229                  *
 230                  * XX always 80
 231                  * YY always 00
 232                  * B1-B4 "should" be the number of send out beacons.
 233                  */
 234                 break;
 235
 236         case CARL9170_RSP_ATIM:
 237                 /* End of Atim Window */
 238                 break;
 239
 240         case CARL9170_RSP_WATCHDOG:
 241                 /* Watchdog Interrupt */
 242                 carl9170_restart(ar, CARL9170_RR_WATCHDOG);
 243                 break;
 244
 245         case CARL9170_RSP_TEXT:
 246                 /* firmware debug */
 247                 carl9170_dbg_message(ar, (char *)buf + 4, len - 4);
 248                 break;
 249
 250         case CARL9170_RSP_HEXDUMP:
 251                 wiphy_dbg(ar->hw->wiphy, "FW: HD %d\n", len - 4);
 252                 print_hex_dump_bytes("FW:", DUMP_PREFIX_NONE,
 253                                      (char *)buf + 4, len - 4);
 254                 break;
 255
 256         case CARL9170_RSP_RADAR:
 257                 if (!net_ratelimit())
 258                         break;
 259
 260                 wiphy_info(ar->hw->wiphy, "FW: RADAR! Please report this "
 261                        "incident to linux-wireless@vger.kernel.org !\n");
 262                 break;
 263
 264         case CARL9170_RSP_GPIO:
 265 #ifdef CONFIG_CARL9170_WPC
 266                 if (ar->wps.pbc) {
 267                         bool state = !!(cmd->gpio.gpio & cpu_to_le32(
 268                                 AR9170_GPIO_PORT_WPS_BUTTON_PRESSED));
 269
 270                         if (state != ar->wps.pbc_state) {
 271                                 ar->wps.pbc_state = state;
 272                                 input_report_key(ar->wps.pbc, KEY_WPS_BUTTON,
 273                                                  state);
 274                                 input_sync(ar->wps.pbc);
 275                         }
 276                 }
 277 #endif /* CONFIG_CARL9170_WPC */
 278                 break;
 279
 280         case CARL9170_RSP_BOOT:
 281                 complete(&ar->fw_boot_wait);
 282                 break;
 283
 284         default:
 285                 wiphy_err(ar->hw->wiphy, "FW: received unhandled event %x\n",
 286                         cmd->hdr.cmd);
 287                 print_hex_dump_bytes("dump:", DUMP_PREFIX_NONE, buf, len);
 288                 break;
 289         }
 290 }
 291
 292 static int carl9170_rx_mac_status(struct ar9170 *ar,
 293         struct ar9170_rx_head *head, struct ar9170_rx_macstatus *mac,
 294         struct ieee80211_rx_status *status)
 295 {
 296         struct ieee80211_channel *chan;
 297         u8 error, decrypt;
 298
 299         BUILD_BUG_ON(sizeof(struct ar9170_rx_head) != 12);
 300         BUILD_BUG_ON(sizeof(struct ar9170_rx_macstatus) != 4);
 301
 302         error = mac->error;
 303
 304         if (error & AR9170_RX_ERROR_WRONG_RA) {
 305                 if (!ar->sniffer_enabled)
 306                         return -EINVAL;
 307         }
 308
 309         if (error & AR9170_RX_ERROR_PLCP) {
 310                 if (!(ar->filter_state & FIF_PLCPFAIL))
 311                         return -EINVAL;
 312
 313                 status->flag |= RX_FLAG_FAILED_PLCP_CRC;
 314         }
 315
 316         if (error & AR9170_RX_ERROR_FCS) {
 317                 ar->tx_fcs_errors++;
 318
 319                 if (!(ar->filter_state & FIF_FCSFAIL))
 320                         return -EINVAL;
 321
 322                 status->flag |= RX_FLAG_FAILED_FCS_CRC;
 323         }
 324
 325         decrypt = ar9170_get_decrypt_type(mac);
 326         if (!(decrypt & AR9170_RX_ENC_SOFTWARE) &&
 327             decrypt != AR9170_ENC_ALG_NONE) {
 328                 if ((decrypt == AR9170_ENC_ALG_TKIP) &&
 329                     (error & AR9170_RX_ERROR_MMIC))
 330                         status->flag |= RX_FLAG_MMIC_ERROR;
 331
 332                 status->flag |= RX_FLAG_DECRYPTED;
 333         }
 334
 335         if (error & AR9170_RX_ERROR_DECRYPT && !ar->sniffer_enabled)
 336                 return -ENODATA;
 337
 338         error &= ~(AR9170_RX_ERROR_MMIC |
 339                    AR9170_RX_ERROR_FCS |
 340                    AR9170_RX_ERROR_WRONG_RA |
 341                    AR9170_RX_ERROR_DECRYPT |
 342                    AR9170_RX_ERROR_PLCP);
 343
 344         /* drop any other error frames */
 345         if (unlikely(error)) {
 346                 /* TODO: update netdevice's RX dropped/errors statistics */
 347
 348                 if (net_ratelimit())
 349                         wiphy_dbg(ar->hw->wiphy, "received frame with "
 350                                "suspicious error code (%#x).\n", error);
 351
 352                 return -EINVAL;
 353         }
 354
 355         chan = ar->channel;
 356         if (chan) {
 357                 status->band = chan->band;
 358                 status->freq = chan->center_freq;
 359         }
 360
 361         switch (mac->status & AR9170_RX_STATUS_MODULATION) {
 362         case AR9170_RX_STATUS_MODULATION_CCK:
 363                 if (mac->status & AR9170_RX_STATUS_SHORT_PREAMBLE)
 364                         status->flag |= RX_FLAG_SHORTPRE;
 365                 switch (head->plcp[0]) {
 366                 case AR9170_RX_PHY_RATE_CCK_1M:
 367                         status->rate_idx = 0;
 368                         break;
 369                 case AR9170_RX_PHY_RATE_CCK_2M:
 370                         status->rate_idx = 1;
 371                         break;
 372                 case AR9170_RX_PHY_RATE_CCK_5M:
 373                         status->rate_idx = 2;
 374                         break;
 375                 case AR9170_RX_PHY_RATE_CCK_11M:
 376                         status->rate_idx = 3;
 377                         break;
 378                 default:
 379                         if (net_ratelimit()) {
 380                                 wiphy_err(ar->hw->wiphy, "invalid plcp cck "
 381                                        "rate (%x).\n", head->plcp[0]);
 382                         }
 383
 384                         return -EINVAL;
 385                 }
 386                 break;
 387
 388         case AR9170_RX_STATUS_MODULATION_DUPOFDM:
 389         case AR9170_RX_STATUS_MODULATION_OFDM:
 390                 switch (head->plcp[0] & 0xf) {
 391                 case AR9170_TXRX_PHY_RATE_OFDM_6M:
 392                         status->rate_idx = 0;
 393                         break;
 394                 case AR9170_TXRX_PHY_RATE_OFDM_9M:
 395                         status->rate_idx = 1;
 396                         break;
 397                 case AR9170_TXRX_PHY_RATE_OFDM_12M:
 398                         status->rate_idx = 2;
 399                         break;
 400                 case AR9170_TXRX_PHY_RATE_OFDM_18M:
 401                         status->rate_idx = 3;
 402                         break;
 403                 case AR9170_TXRX_PHY_RATE_OFDM_24M:
 404                         status->rate_idx = 4;
 405                         break;
 406                 case AR9170_TXRX_PHY_RATE_OFDM_36M:
 407                         status->rate_idx = 5;
 408                         break;
 409                 case AR9170_TXRX_PHY_RATE_OFDM_48M:
 410                         status->rate_idx = 6;
 411                         break;
 412                 case AR9170_TXRX_PHY_RATE_OFDM_54M:
 413                         status->rate_idx = 7;
 414                         break;
 415                 default:
 416                         if (net_ratelimit()) {
 417                                 wiphy_err(ar->hw->wiphy, "invalid plcp ofdm "
 418                                         "rate (%x).\n", head->plcp[0]);
 419                         }
 420
 421                         return -EINVAL;
 422                 }
 423                 if (status->band == IEEE80211_BAND_2GHZ)
 424                         status->rate_idx += 4;
 425                 break;
 426
 427         case AR9170_RX_STATUS_MODULATION_HT:
 428                 if (head->plcp[3] & 0x80)
 429                         status->flag |= RX_FLAG_40MHZ;
 430                 if (head->plcp[6] & 0x80)
 431                         status->flag |= RX_FLAG_SHORT_GI;
 432
 433                 status->rate_idx = clamp(0, 75, head->plcp[3] & 0x7f);
 434                 status->flag |= RX_FLAG_HT;
 435                 break;
 436
 437         default:
 438                 BUG();
 439                 return -ENOSYS;
 440         }
 441
 442         return 0;
 443 }
 444
 445 static void carl9170_rx_phy_status(struct ar9170 *ar,
 446         struct ar9170_rx_phystatus *phy, struct ieee80211_rx_status *status)
 447 {
 448         int i;
 449
 450         BUILD_BUG_ON(sizeof(struct ar9170_rx_phystatus) != 20);
 451
 452         for (i = 0; i < 3; i++)
 453                 if (phy->rssi[i] != 0x80)
 454                         status->antenna |= BIT(i);
 455
 456         /* post-process RSSI */
 457         for (i = 0; i < 7; i++)
 458                 if (phy->rssi[i] & 0x80)
 459                         phy->rssi[i] = ((phy->rssi[i] & 0x7f) + 1) & 0x7f;
 460
 461         /* TODO: we could do something with phy_errors */
 462         status->signal = ar->noise[0] + phy->rssi_combined;
 463 }
 464
 465 static struct sk_buff *carl9170_rx_copy_data(u8 *buf, int len)
 466 {
 467         struct sk_buff *skb;
 468         int reserved = 0;
 469         struct ieee80211_hdr *hdr = (void *) buf;
 470
 471         if (ieee80211_is_data_qos(hdr->frame_control)) {
 472                 u8 *qc = ieee80211_get_qos_ctl(hdr);
 473                 reserved += NET_IP_ALIGN;
 474
 475                 if (*qc & IEEE80211_QOS_CONTROL_A_MSDU_PRESENT)
 476                         reserved += NET_IP_ALIGN;
 477         }
 478
 479         if (ieee80211_has_a4(hdr->frame_control))
 480                 reserved += NET_IP_ALIGN;
 481
 482         reserved = 32 + (reserved & NET_IP_ALIGN);
 483
 484         skb = dev_alloc_skb(len + reserved);
 485         if (likely(skb)) {
 486                 skb_reserve(skb, reserved);
 487                 memcpy(skb_put(skb, len), buf, len);
 488         }
 489
 490         return skb;
 491 }
 492
 493 static u8 *carl9170_find_ie(u8 *data, unsigned int len, u8 ie)
 494 {
 495         struct ieee80211_mgmt *mgmt = (void *)data;
 496         u8 *pos, *end;
 497
 498         pos = (u8 *)mgmt->u.beacon.variable;
 499         end = data + len;
 500         while (pos < end) {
 501                 if (pos + 2 + pos[1] > end)
 502                         return NULL;
 503
 504                 if (pos[0] == ie)
 505                         return pos;
 506
 507                 pos += 2 + pos[1];
 508         }
 509         return NULL;
 510 }
 511
 512 /*
 513  * NOTE:
 514  *
 515  * The firmware is in charge of waking up the device just before
 516  * the AP is expected to transmit the next beacon.
 517  *
 518  * This leaves the driver with the important task of deciding when
 519  * to set the PHY back to bed again.
 520  */
 521 static void carl9170_ps_beacon(struct ar9170 *ar, void *data, unsigned int len)
 522 {
 523         struct ieee80211_hdr *hdr = (void *) data;
 524         struct ieee80211_tim_ie *tim_ie;
 525         u8 *tim;
 526         u8 tim_len;
 527         bool cam;
 528
 529         if (likely(!(ar->hw->conf.flags & IEEE80211_CONF_PS)))
 530                 return;
 531
 532         /* check if this really is a beacon */
 533         if (!ieee80211_is_beacon(hdr->frame_control))
 534                 return;
 535
 536         /* min. beacon length + FCS_LEN */
 537         if (len <= 40 + FCS_LEN)
 538                 return;
 539
 540         /* and only beacons from the associated BSSID, please */
 541         if (compare_ether_addr(hdr->addr3, ar->common.curbssid) ||
 542             !ar->common.curaid)
 543                 return;
 544
 545         ar->ps.last_beacon = jiffies;
 546
 547         tim = carl9170_find_ie(data, len - FCS_LEN, WLAN_EID_TIM);
 548         if (!tim)
 549                 return;
 550
 551         if (tim[1] < sizeof(*tim_ie))
 552                 return;
 553
 554         tim_len = tim[1];
 555         tim_ie = (struct ieee80211_tim_ie *) &tim[2];
 556
 557         if (!WARN_ON_ONCE(!ar->hw->conf.ps_dtim_period))
 558                 ar->ps.dtim_counter = (tim_ie->dtim_count - 1) %
 559                         ar->hw->conf.ps_dtim_period;
 560
 561         /* Check whenever the PHY can be turned off again. */
 562
 563         /* 1. What about buffered unicast traffic for our AID? */
 564         cam = ieee80211_check_tim(tim_ie, tim_len, ar->common.curaid);
 565
 566         /* 2. Maybe the AP wants to send multicast/broadcast data? */
 567         cam |= !!(tim_ie->bitmap_ctrl & 0x01);
 568
 569         if (!cam) {
 570                 /* back to low-power land. */
 571                 ar->ps.off_override &= ~PS_OFF_BCN;
 572                 carl9170_ps_check(ar);
 573         } else {
 574                 /* force CAM */
 575                 ar->ps.off_override |= PS_OFF_BCN;
 576         }
 577 }
 578
 579 static bool carl9170_ampdu_check(struct ar9170 *ar, u8 *buf, u8 ms)
 580 {
 581         __le16 fc;
 582
 583         if ((ms & AR9170_RX_STATUS_MPDU) == AR9170_RX_STATUS_MPDU_SINGLE) {
 584                 /*
 585                  * This frame is not part of an aMPDU.
 586                  * Therefore it is not subjected to any
 587                  * of the following content restrictions.
 588                  */
 589                 return true;
 590         }
 591
 592         /*
 593          * "802.11n - 7.4a.3 A-MPDU contents" describes in which contexts
 594          * certain frame types can be part of an aMPDU.
 595          *
 596          * In order to keep the processing cost down, I opted for a
 597          * stateless filter solely based on the frame control field.
 598          */
 599
 600         fc = ((struct ieee80211_hdr *)buf)->frame_control;
 601         if (ieee80211_is_data_qos(fc) && ieee80211_is_data_present(fc))
 602                 return true;
 603
 604         if (ieee80211_is_ack(fc) || ieee80211_is_back(fc) ||
 605             ieee80211_is_back_req(fc))
 606                 return true;
 607
 608         if (ieee80211_is_action(fc))
 609                 return true;
 610
 611         return false;
 612 }
 613
 614 /*
 615  * If the frame alignment is right (or the kernel has
 616  * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS), and there
 617  * is only a single MPDU in the USB frame, then we could
 618  * submit to mac80211 the SKB directly. However, since
 619  * there may be multiple packets in one SKB in stream
 620  * mode, and we need to observe the proper ordering,
 621  * this is non-trivial.
 622  */
 623
 624 static void carl9170_handle_mpdu(struct ar9170 *ar, u8 *buf, int len)
 625 {
 626         struct ar9170_rx_head *head;
 627         struct ar9170_rx_macstatus *mac;
 628         struct ar9170_rx_phystatus *phy = NULL;
 629         struct ieee80211_rx_status status;
 630         struct sk_buff *skb;
 631         int mpdu_len;
 632         u8 mac_status;
 633
 634         if (!IS_STARTED(ar))
 635                 return;
 636
 637         if (unlikely(len < sizeof(*mac)))
 638                 goto drop;
 639
 640         mpdu_len = len - sizeof(*mac);
 641
 642         mac = (void *)(buf + mpdu_len);
 643         mac_status = mac->status;
 644         switch (mac_status & AR9170_RX_STATUS_MPDU) {
 645         case AR9170_RX_STATUS_MPDU_FIRST:
 646                 /* Aggregated MPDUs start with an PLCP header */
 647                 if (likely(mpdu_len >= sizeof(struct ar9170_rx_head))) {
 648                         head = (void *) buf;
 649
 650                         /*
 651                          * The PLCP header needs to be cached for the
 652                          * following MIDDLE + LAST A-MPDU packets.
 653                          *
 654                          * So, if you are wondering why all frames seem
 655                          * to share a common RX status information,
 656                          * then you have the answer right here...
 657                          */
 658                         memcpy(&ar->rx_plcp, (void *) buf,
 659                                sizeof(struct ar9170_rx_head));
 660
 661                         mpdu_len -= sizeof(struct ar9170_rx_head);
 662                         buf += sizeof(struct ar9170_rx_head);
 663
 664                         ar->rx_has_plcp = true;
 665                 } else {
 666                         if (net_ratelimit()) {
 667                                 wiphy_err(ar->hw->wiphy, "plcp info "
 668                                         "is clipped.\n");
 669                         }
 670
 671                         goto drop;
 672                 }
 673                 break;
 674
 675         case AR9170_RX_STATUS_MPDU_LAST:
 676                 /*
 677                  * The last frame of an A-MPDU has an extra tail
 678                  * which does contain the phy status of the whole
 679                  * aggregate.
 680                  */
 681
 682                 if (likely(mpdu_len >= sizeof(struct ar9170_rx_phystatus))) {
 683                         mpdu_len -= sizeof(struct ar9170_rx_phystatus);
 684                         phy = (void *)(buf + mpdu_len);
 685                 } else {
 686                         if (net_ratelimit()) {
 687                                 wiphy_err(ar->hw->wiphy, "frame tail "
 688                                         "is clipped.\n");
 689                         }
 690
 691                         goto drop;
 692                 }
 693
 694         case AR9170_RX_STATUS_MPDU_MIDDLE:
 695                 /*  These are just data + mac status */
 696                 if (unlikely(!ar->rx_has_plcp)) {
 697                         if (!net_ratelimit())
 698                                 return;
 699
 700                         wiphy_err(ar->hw->wiphy, "rx stream does not start "
 701                                         "with a first_mpdu frame tag.\n");
 702
 703                         goto drop;
 704                 }
 705
 706                 head = &ar->rx_plcp;
 707                 break;
 708
 709         case AR9170_RX_STATUS_MPDU_SINGLE:
 710                 /* single mpdu has both: plcp (head) and phy status (tail) */
 711                 head = (void *) buf;
 712
 713                 mpdu_len -= sizeof(struct ar9170_rx_head);
 714                 mpdu_len -= sizeof(struct ar9170_rx_phystatus);
 715
 716                 buf += sizeof(struct ar9170_rx_head);
 717                 phy = (void *)(buf + mpdu_len);
 718                 break;
 719
 720         default:
 721                 BUG_ON(1);
 722                 break;
 723         }
 724
 725         /* FC + DU + RA + FCS */
 726         if (unlikely(mpdu_len < (2 + 2 + ETH_ALEN + FCS_LEN)))
 727                 goto drop;
 728
 729         memset(&status, 0, sizeof(status));
 730         if (unlikely(carl9170_rx_mac_status(ar, head, mac, &status)))
 731                 goto drop;
 732
 733         if (!carl9170_ampdu_check(ar, buf, mac_status))
 734                 goto drop;
 735
 736         if (phy)
 737                 carl9170_rx_phy_status(ar, phy, &status);
 738
 739         carl9170_ps_beacon(ar, buf, mpdu_len);
 740
 741         skb = carl9170_rx_copy_data(buf, mpdu_len);
 742         if (!skb)
 743                 goto drop;
 744
 745         memcpy(IEEE80211_SKB_RXCB(skb), &status, sizeof(status));
 746         ieee80211_rx(ar->hw, skb);
 747         return;
 748
 749 drop:
 750         ar->rx_dropped++;
 751 }
 752
 753 static void carl9170_rx_untie_cmds(struct ar9170 *ar, const u8 *respbuf,
 754                                    const unsigned int resplen)
 755 {
 756         struct carl9170_rsp *cmd;
 757         int i = 0;
 758
 759         while (i < resplen) {
 760                 cmd = (void *) &respbuf[i];
 761
 762                 i += cmd->hdr.len + 4;
 763                 if (unlikely(i > resplen))
 764                         break;
 765
 766                 carl9170_handle_command_response(ar, cmd, cmd->hdr.len + 4);
 767         }
 768
 769         if (unlikely(i != resplen)) {
 770                 if (!net_ratelimit())
 771                         return;
 772
 773                 wiphy_err(ar->hw->wiphy, "malformed firmware trap:\n");
 774                 print_hex_dump_bytes("rxcmd:", DUMP_PREFIX_OFFSET,
 775                                      respbuf, resplen);
 776         }
 777 }
 778
 779 static void __carl9170_rx(struct ar9170 *ar, u8 *buf, unsigned int len)
 780 {
 781         unsigned int i = 0;
 782
 783         /* weird thing, but this is the same in the original driver */
 784         while (len > 2 && i < 12 && buf[0] == 0xff && buf[1] == 0xff) {
 785                 i += 2;
 786                 len -= 2;
 787                 buf += 2;
 788         }
 789
 790         if (unlikely(len < 4))
 791                 return;
 792
 793         /* found the 6 * 0xffff marker? */
 794         if (i == 12)
 795                 carl9170_rx_untie_cmds(ar, buf, len);
 796         else
 797                 carl9170_handle_mpdu(ar, buf, len);
 798 }
 799
 800 static void carl9170_rx_stream(struct ar9170 *ar, void *buf, unsigned int len)
 801 {
 802         unsigned int tlen, wlen = 0, clen = 0;
 803         struct ar9170_stream *rx_stream;
 804         u8 *tbuf;
 805
 806         tbuf = buf;
 807         tlen = len;
 808
 809         while (tlen >= 4) {
 810                 rx_stream = (void *) tbuf;
 811                 clen = le16_to_cpu(rx_stream->length);
 812                 wlen = ALIGN(clen, 4);
 813
 814                 /* check if this is stream has a valid tag.*/
 815                 if (rx_stream->tag != cpu_to_le16(AR9170_RX_STREAM_TAG)) {
 816                         /*
 817                          * TODO: handle the highly unlikely event that the
 818                          * corrupted stream has the TAG at the right position.
 819                          */
 820
 821                         /* check if the frame can be repaired. */
 822                         if (!ar->rx_failover_missing) {
 823
 824                                 /* this is not "short read". */
 825                                 if (net_ratelimit()) {
 826                                         wiphy_err(ar->hw->wiphy,
 827                                                 "missing tag!\n");
 828                                 }
 829
 830                                 __carl9170_rx(ar, tbuf, tlen);
 831                                 return;
 832                         }
 833
 834                         if (ar->rx_failover_missing > tlen) {
 835                                 if (net_ratelimit()) {
 836                                         wiphy_err(ar->hw->wiphy,
 837                                                 "possible multi "
 838                                                 "stream corruption!\n");
 839                                         goto err_telluser;
 840                                 } else {
 841                                         goto err_silent;
 842                                 }
 843                         }
 844
 845                         memcpy(skb_put(ar->rx_failover, tlen), tbuf, tlen);
 846                         ar->rx_failover_missing -= tlen;
 847
 848                         if (ar->rx_failover_missing <= 0) {
 849                                 /*
 850                                  * nested carl9170_rx_stream call!
 851                                  *
 852                                  * termination is guaranteed, even when the
 853                                  * combined frame also have an element with
 854                                  * a bad tag.
 855                                  */
 856
 857                                 ar->rx_failover_missing = 0;
 858                                 carl9170_rx_stream(ar, ar->rx_failover->data,
 859                                                    ar->rx_failover->len);
 860
 861                                 skb_reset_tail_pointer(ar->rx_failover);
 862                                 skb_trim(ar->rx_failover, 0);
 863                         }
 864
 865                         return;
 866                 }
 867
 868                 /* check if stream is clipped */
 869                 if (wlen > tlen - 4) {
 870                         if (ar->rx_failover_missing) {
 871                                 /* TODO: handle double stream corruption. */
 872                                 if (net_ratelimit()) {
 873                                         wiphy_err(ar->hw->wiphy, "double rx "
 874                                                 "stream corruption!\n");
 875                                         goto err_telluser;
 876                                 } else {
 877                                         goto err_silent;
 878                                 }
 879                         }
 880
 881                         /*
 882                          * save incomplete data set.
 883                          * the firmware will resend the missing bits when
 884                          * the rx - descriptor comes round again.
 885                          */
 886
 887                         memcpy(skb_put(ar->rx_failover, tlen), tbuf, tlen);
 888                         ar->rx_failover_missing = clen - tlen;
 889                         return;
 890                 }
 891                 __carl9170_rx(ar, rx_stream->payload, clen);
 892
 893                 tbuf += wlen + 4;
 894                 tlen -= wlen + 4;
 895         }
 896
 897         if (tlen) {
 898                 if (net_ratelimit()) {
 899                         wiphy_err(ar->hw->wiphy, "%d bytes of unprocessed "
 900                                 "data left in rx stream!\n", tlen);
 901                 }
 902
 903                 goto err_telluser;
 904         }
 905
 906         return;
 907
 908 err_telluser:
 909         wiphy_err(ar->hw->wiphy, "damaged RX stream data [want:%d, "
 910                 "data:%d, rx:%d, pending:%d ]\n", clen, wlen, tlen,
 911                 ar->rx_failover_missing);
 912
 913         if (ar->rx_failover_missing)
 914                 print_hex_dump_bytes("rxbuf:", DUMP_PREFIX_OFFSET,
 915                                      ar->rx_failover->data,
 916                                      ar->rx_failover->len);
 917
 918         print_hex_dump_bytes("stream:", DUMP_PREFIX_OFFSET,
 919                              buf, len);
 920
 921         wiphy_err(ar->hw->wiphy, "please check your hardware and cables, if "
 922                 "you see this message frequently.\n");
 923
 924 err_silent:
 925         if (ar->rx_failover_missing) {
 926                 skb_reset_tail_pointer(ar->rx_failover);
 927                 skb_trim(ar->rx_failover, 0);
 928                 ar->rx_failover_missing = 0;
 929         }
 930 }
 931
 932 void carl9170_rx(struct ar9170 *ar, void *buf, unsigned int len)
 933 {
 934         if (ar->fw.rx_stream)
 935                 carl9170_rx_stream(ar, buf, len);
 936         else
 937                 __carl9170_rx(ar, buf, len);
 938 }