]> git.karo-electronics.de Git - mv-sheeva.git/blobdiff - drivers/net/wireless/ath/carl9170/rx.c
Merge branch 'master' into csb1725
[mv-sheeva.git] / drivers / net / wireless / ath / carl9170 / rx.c
diff --git a/drivers/net/wireless/ath/carl9170/rx.c b/drivers/net/wireless/ath/carl9170/rx.c
new file mode 100644 (file)
index 0000000..939a0e9
--- /dev/null
@@ -0,0 +1,938 @@
+/*
+ * Atheros CARL9170 driver
+ *
+ * 802.11 & command trap routines
+ *
+ * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
+ * Copyright 2009, 2010, Christian Lamparter <chunkeey@googlemail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, see
+ * http://www.gnu.org/licenses/.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *    Copyright (c) 2007-2008 Atheros Communications, Inc.
+ *
+ *    Permission to use, copy, modify, and/or distribute this software for any
+ *    purpose with or without fee is hereby granted, provided that the above
+ *    copyright notice and this permission notice appear in all copies.
+ *
+ *    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/etherdevice.h>
+#include <linux/crc32.h>
+#include <net/mac80211.h>
+#include "carl9170.h"
+#include "hw.h"
+#include "cmd.h"
+
+static void carl9170_dbg_message(struct ar9170 *ar, const char *buf, u32 len)
+{
+       bool restart = false;
+       enum carl9170_restart_reasons reason = CARL9170_RR_NO_REASON;
+
+       if (len > 3) {
+               if (memcmp(buf, CARL9170_ERR_MAGIC, 3) == 0) {
+                       ar->fw.err_counter++;
+                       if (ar->fw.err_counter > 3) {
+                               restart = true;
+                               reason = CARL9170_RR_TOO_MANY_FIRMWARE_ERRORS;
+                       }
+               }
+
+               if (memcmp(buf, CARL9170_BUG_MAGIC, 3) == 0) {
+                       ar->fw.bug_counter++;
+                       restart = true;
+                       reason = CARL9170_RR_FATAL_FIRMWARE_ERROR;
+               }
+       }
+
+       wiphy_info(ar->hw->wiphy, "FW: %.*s\n", len, buf);
+
+       if (restart)
+               carl9170_restart(ar, reason);
+}
+
+static void carl9170_handle_ps(struct ar9170 *ar, struct carl9170_rsp *rsp)
+{
+       u32 ps;
+       bool new_ps;
+
+       ps = le32_to_cpu(rsp->psm.state);
+
+       new_ps = (ps & CARL9170_PSM_COUNTER) != CARL9170_PSM_WAKE;
+       if (ar->ps.state != new_ps) {
+               if (!new_ps) {
+                       ar->ps.sleep_ms = jiffies_to_msecs(jiffies -
+                               ar->ps.last_action);
+               }
+
+               ar->ps.last_action = jiffies;
+
+               ar->ps.state = new_ps;
+       }
+}
+
+static int carl9170_check_sequence(struct ar9170 *ar, unsigned int seq)
+{
+       if (ar->cmd_seq < -1)
+               return 0;
+
+       /*
+        * Initialize Counter
+        */
+       if (ar->cmd_seq < 0)
+               ar->cmd_seq = seq;
+
+       /*
+        * The sequence is strictly monotonic increasing and it never skips!
+        *
+        * Therefore we can safely assume that whenever we received an
+        * unexpected sequence we have lost some valuable data.
+        */
+       if (seq != ar->cmd_seq) {
+               int count;
+
+               count = (seq - ar->cmd_seq) % ar->fw.cmd_bufs;
+
+               wiphy_err(ar->hw->wiphy, "lost %d command responses/traps! "
+                         "w:%d g:%d\n", count, ar->cmd_seq, seq);
+
+               carl9170_restart(ar, CARL9170_RR_LOST_RSP);
+               return -EIO;
+       }
+
+       ar->cmd_seq = (ar->cmd_seq + 1) % ar->fw.cmd_bufs;
+       return 0;
+}
+
+static void carl9170_cmd_callback(struct ar9170 *ar, u32 len, void *buffer)
+{
+       /*
+        * Some commands may have a variable response length
+        * and we cannot predict the correct length in advance.
+        * So we only check if we provided enough space for the data.
+        */
+       if (unlikely(ar->readlen != (len - 4))) {
+               dev_warn(&ar->udev->dev, "received invalid command response:"
+                        "got %d, instead of %d\n", len - 4, ar->readlen);
+               print_hex_dump_bytes("carl9170 cmd:", DUMP_PREFIX_OFFSET,
+                       ar->cmd_buf, (ar->cmd.hdr.len + 4) & 0x3f);
+               print_hex_dump_bytes("carl9170 rsp:", DUMP_PREFIX_OFFSET,
+                       buffer, len);
+               /*
+                * Do not complete. The command times out,
+                * and we get a stack trace from there.
+                */
+               carl9170_restart(ar, CARL9170_RR_INVALID_RSP);
+       }
+
+       spin_lock(&ar->cmd_lock);
+       if (ar->readbuf) {
+               if (len >= 4)
+                       memcpy(ar->readbuf, buffer + 4, len - 4);
+
+               ar->readbuf = NULL;
+       }
+       complete(&ar->cmd_wait);
+       spin_unlock(&ar->cmd_lock);
+}
+
+void carl9170_handle_command_response(struct ar9170 *ar, void *buf, u32 len)
+{
+       struct carl9170_rsp *cmd = (void *) buf;
+       struct ieee80211_vif *vif;
+
+       if (carl9170_check_sequence(ar, cmd->hdr.seq))
+               return;
+
+       if ((cmd->hdr.cmd & CARL9170_RSP_FLAG) != CARL9170_RSP_FLAG) {
+               if (!(cmd->hdr.cmd & CARL9170_CMD_ASYNC_FLAG))
+                       carl9170_cmd_callback(ar, len, buf);
+
+               return;
+       }
+
+       if (unlikely(cmd->hdr.len != (len - 4))) {
+               if (net_ratelimit()) {
+                       wiphy_err(ar->hw->wiphy, "FW: received over-/under"
+                               "sized event %x (%d, but should be %d).\n",
+                              cmd->hdr.cmd, cmd->hdr.len, len - 4);
+
+                       print_hex_dump_bytes("dump:", DUMP_PREFIX_NONE,
+                                            buf, len);
+               }
+
+               return;
+       }
+
+       /* hardware event handlers */
+       switch (cmd->hdr.cmd) {
+       case CARL9170_RSP_PRETBTT:
+               /* pre-TBTT event */
+               rcu_read_lock();
+               vif = carl9170_get_main_vif(ar);
+
+               if (!vif) {
+                       rcu_read_unlock();
+                       break;
+               }
+
+               switch (vif->type) {
+               case NL80211_IFTYPE_STATION:
+                       carl9170_handle_ps(ar, cmd);
+                       break;
+
+               case NL80211_IFTYPE_AP:
+               case NL80211_IFTYPE_ADHOC:
+                       carl9170_update_beacon(ar, true);
+                       break;
+
+               default:
+                       break;
+               }
+               rcu_read_unlock();
+
+               break;
+
+
+       case CARL9170_RSP_TXCOMP:
+               /* TX status notification */
+               carl9170_tx_process_status(ar, cmd);
+               break;
+
+       case CARL9170_RSP_BEACON_CONFIG:
+               /*
+                * (IBSS) beacon send notification
+                * bytes: 04 c2 XX YY B4 B3 B2 B1
+                *
+                * XX always 80
+                * YY always 00
+                * B1-B4 "should" be the number of send out beacons.
+                */
+               break;
+
+       case CARL9170_RSP_ATIM:
+               /* End of Atim Window */
+               break;
+
+       case CARL9170_RSP_WATCHDOG:
+               /* Watchdog Interrupt */
+               carl9170_restart(ar, CARL9170_RR_WATCHDOG);
+               break;
+
+       case CARL9170_RSP_TEXT:
+               /* firmware debug */
+               carl9170_dbg_message(ar, (char *)buf + 4, len - 4);
+               break;
+
+       case CARL9170_RSP_HEXDUMP:
+               wiphy_dbg(ar->hw->wiphy, "FW: HD %d\n", len - 4);
+               print_hex_dump_bytes("FW:", DUMP_PREFIX_NONE,
+                                    (char *)buf + 4, len - 4);
+               break;
+
+       case CARL9170_RSP_RADAR:
+               if (!net_ratelimit())
+                       break;
+
+               wiphy_info(ar->hw->wiphy, "FW: RADAR! Please report this "
+                      "incident to linux-wireless@vger.kernel.org !\n");
+               break;
+
+       case CARL9170_RSP_GPIO:
+#ifdef CONFIG_CARL9170_WPC
+               if (ar->wps.pbc) {
+                       bool state = !!(cmd->gpio.gpio & cpu_to_le32(
+                               AR9170_GPIO_PORT_WPS_BUTTON_PRESSED));
+
+                       if (state != ar->wps.pbc_state) {
+                               ar->wps.pbc_state = state;
+                               input_report_key(ar->wps.pbc, KEY_WPS_BUTTON,
+                                                state);
+                               input_sync(ar->wps.pbc);
+                       }
+               }
+#endif /* CONFIG_CARL9170_WPC */
+               break;
+
+       case CARL9170_RSP_BOOT:
+               complete(&ar->fw_boot_wait);
+               break;
+
+       default:
+               wiphy_err(ar->hw->wiphy, "FW: received unhandled event %x\n",
+                       cmd->hdr.cmd);
+               print_hex_dump_bytes("dump:", DUMP_PREFIX_NONE, buf, len);
+               break;
+       }
+}
+
+static int carl9170_rx_mac_status(struct ar9170 *ar,
+       struct ar9170_rx_head *head, struct ar9170_rx_macstatus *mac,
+       struct ieee80211_rx_status *status)
+{
+       struct ieee80211_channel *chan;
+       u8 error, decrypt;
+
+       BUILD_BUG_ON(sizeof(struct ar9170_rx_head) != 12);
+       BUILD_BUG_ON(sizeof(struct ar9170_rx_macstatus) != 4);
+
+       error = mac->error;
+
+       if (error & AR9170_RX_ERROR_WRONG_RA) {
+               if (!ar->sniffer_enabled)
+                       return -EINVAL;
+       }
+
+       if (error & AR9170_RX_ERROR_PLCP) {
+               if (!(ar->filter_state & FIF_PLCPFAIL))
+                       return -EINVAL;
+
+               status->flag |= RX_FLAG_FAILED_PLCP_CRC;
+       }
+
+       if (error & AR9170_RX_ERROR_FCS) {
+               ar->tx_fcs_errors++;
+
+               if (!(ar->filter_state & FIF_FCSFAIL))
+                       return -EINVAL;
+
+               status->flag |= RX_FLAG_FAILED_FCS_CRC;
+       }
+
+       decrypt = ar9170_get_decrypt_type(mac);
+       if (!(decrypt & AR9170_RX_ENC_SOFTWARE) &&
+           decrypt != AR9170_ENC_ALG_NONE) {
+               if ((decrypt == AR9170_ENC_ALG_TKIP) &&
+                   (error & AR9170_RX_ERROR_MMIC))
+                       status->flag |= RX_FLAG_MMIC_ERROR;
+
+               status->flag |= RX_FLAG_DECRYPTED;
+       }
+
+       if (error & AR9170_RX_ERROR_DECRYPT && !ar->sniffer_enabled)
+               return -ENODATA;
+
+       error &= ~(AR9170_RX_ERROR_MMIC |
+                  AR9170_RX_ERROR_FCS |
+                  AR9170_RX_ERROR_WRONG_RA |
+                  AR9170_RX_ERROR_DECRYPT |
+                  AR9170_RX_ERROR_PLCP);
+
+       /* drop any other error frames */
+       if (unlikely(error)) {
+               /* TODO: update netdevice's RX dropped/errors statistics */
+
+               if (net_ratelimit())
+                       wiphy_dbg(ar->hw->wiphy, "received frame with "
+                              "suspicious error code (%#x).\n", error);
+
+               return -EINVAL;
+       }
+
+       chan = ar->channel;
+       if (chan) {
+               status->band = chan->band;
+               status->freq = chan->center_freq;
+       }
+
+       switch (mac->status & AR9170_RX_STATUS_MODULATION) {
+       case AR9170_RX_STATUS_MODULATION_CCK:
+               if (mac->status & AR9170_RX_STATUS_SHORT_PREAMBLE)
+                       status->flag |= RX_FLAG_SHORTPRE;
+               switch (head->plcp[0]) {
+               case AR9170_RX_PHY_RATE_CCK_1M:
+                       status->rate_idx = 0;
+                       break;
+               case AR9170_RX_PHY_RATE_CCK_2M:
+                       status->rate_idx = 1;
+                       break;
+               case AR9170_RX_PHY_RATE_CCK_5M:
+                       status->rate_idx = 2;
+                       break;
+               case AR9170_RX_PHY_RATE_CCK_11M:
+                       status->rate_idx = 3;
+                       break;
+               default:
+                       if (net_ratelimit()) {
+                               wiphy_err(ar->hw->wiphy, "invalid plcp cck "
+                                      "rate (%x).\n", head->plcp[0]);
+                       }
+
+                       return -EINVAL;
+               }
+               break;
+
+       case AR9170_RX_STATUS_MODULATION_DUPOFDM:
+       case AR9170_RX_STATUS_MODULATION_OFDM:
+               switch (head->plcp[0] & 0xf) {
+               case AR9170_TXRX_PHY_RATE_OFDM_6M:
+                       status->rate_idx = 0;
+                       break;
+               case AR9170_TXRX_PHY_RATE_OFDM_9M:
+                       status->rate_idx = 1;
+                       break;
+               case AR9170_TXRX_PHY_RATE_OFDM_12M:
+                       status->rate_idx = 2;
+                       break;
+               case AR9170_TXRX_PHY_RATE_OFDM_18M:
+                       status->rate_idx = 3;
+                       break;
+               case AR9170_TXRX_PHY_RATE_OFDM_24M:
+                       status->rate_idx = 4;
+                       break;
+               case AR9170_TXRX_PHY_RATE_OFDM_36M:
+                       status->rate_idx = 5;
+                       break;
+               case AR9170_TXRX_PHY_RATE_OFDM_48M:
+                       status->rate_idx = 6;
+                       break;
+               case AR9170_TXRX_PHY_RATE_OFDM_54M:
+                       status->rate_idx = 7;
+                       break;
+               default:
+                       if (net_ratelimit()) {
+                               wiphy_err(ar->hw->wiphy, "invalid plcp ofdm "
+                                       "rate (%x).\n", head->plcp[0]);
+                       }
+
+                       return -EINVAL;
+               }
+               if (status->band == IEEE80211_BAND_2GHZ)
+                       status->rate_idx += 4;
+               break;
+
+       case AR9170_RX_STATUS_MODULATION_HT:
+               if (head->plcp[3] & 0x80)
+                       status->flag |= RX_FLAG_40MHZ;
+               if (head->plcp[6] & 0x80)
+                       status->flag |= RX_FLAG_SHORT_GI;
+
+               status->rate_idx = clamp(0, 75, head->plcp[3] & 0x7f);
+               status->flag |= RX_FLAG_HT;
+               break;
+
+       default:
+               BUG();
+               return -ENOSYS;
+       }
+
+       return 0;
+}
+
+static void carl9170_rx_phy_status(struct ar9170 *ar,
+       struct ar9170_rx_phystatus *phy, struct ieee80211_rx_status *status)
+{
+       int i;
+
+       BUILD_BUG_ON(sizeof(struct ar9170_rx_phystatus) != 20);
+
+       for (i = 0; i < 3; i++)
+               if (phy->rssi[i] != 0x80)
+                       status->antenna |= BIT(i);
+
+       /* post-process RSSI */
+       for (i = 0; i < 7; i++)
+               if (phy->rssi[i] & 0x80)
+                       phy->rssi[i] = ((phy->rssi[i] & 0x7f) + 1) & 0x7f;
+
+       /* TODO: we could do something with phy_errors */
+       status->signal = ar->noise[0] + phy->rssi_combined;
+}
+
+static struct sk_buff *carl9170_rx_copy_data(u8 *buf, int len)
+{
+       struct sk_buff *skb;
+       int reserved = 0;
+       struct ieee80211_hdr *hdr = (void *) buf;
+
+       if (ieee80211_is_data_qos(hdr->frame_control)) {
+               u8 *qc = ieee80211_get_qos_ctl(hdr);
+               reserved += NET_IP_ALIGN;
+
+               if (*qc & IEEE80211_QOS_CONTROL_A_MSDU_PRESENT)
+                       reserved += NET_IP_ALIGN;
+       }
+
+       if (ieee80211_has_a4(hdr->frame_control))
+               reserved += NET_IP_ALIGN;
+
+       reserved = 32 + (reserved & NET_IP_ALIGN);
+
+       skb = dev_alloc_skb(len + reserved);
+       if (likely(skb)) {
+               skb_reserve(skb, reserved);
+               memcpy(skb_put(skb, len), buf, len);
+       }
+
+       return skb;
+}
+
+static u8 *carl9170_find_ie(u8 *data, unsigned int len, u8 ie)
+{
+       struct ieee80211_mgmt *mgmt = (void *)data;
+       u8 *pos, *end;
+
+       pos = (u8 *)mgmt->u.beacon.variable;
+       end = data + len;
+       while (pos < end) {
+               if (pos + 2 + pos[1] > end)
+                       return NULL;
+
+               if (pos[0] == ie)
+                       return pos;
+
+               pos += 2 + pos[1];
+       }
+       return NULL;
+}
+
+/*
+ * NOTE:
+ *
+ * The firmware is in charge of waking up the device just before
+ * the AP is expected to transmit the next beacon.
+ *
+ * This leaves the driver with the important task of deciding when
+ * to set the PHY back to bed again.
+ */
+static void carl9170_ps_beacon(struct ar9170 *ar, void *data, unsigned int len)
+{
+       struct ieee80211_hdr *hdr = (void *) data;
+       struct ieee80211_tim_ie *tim_ie;
+       u8 *tim;
+       u8 tim_len;
+       bool cam;
+
+       if (likely(!(ar->hw->conf.flags & IEEE80211_CONF_PS)))
+               return;
+
+       /* check if this really is a beacon */
+       if (!ieee80211_is_beacon(hdr->frame_control))
+               return;
+
+       /* min. beacon length + FCS_LEN */
+       if (len <= 40 + FCS_LEN)
+               return;
+
+       /* and only beacons from the associated BSSID, please */
+       if (compare_ether_addr(hdr->addr3, ar->common.curbssid) ||
+           !ar->common.curaid)
+               return;
+
+       ar->ps.last_beacon = jiffies;
+
+       tim = carl9170_find_ie(data, len - FCS_LEN, WLAN_EID_TIM);
+       if (!tim)
+               return;
+
+       if (tim[1] < sizeof(*tim_ie))
+               return;
+
+       tim_len = tim[1];
+       tim_ie = (struct ieee80211_tim_ie *) &tim[2];
+
+       if (!WARN_ON_ONCE(!ar->hw->conf.ps_dtim_period))
+               ar->ps.dtim_counter = (tim_ie->dtim_count - 1) %
+                       ar->hw->conf.ps_dtim_period;
+
+       /* Check whenever the PHY can be turned off again. */
+
+       /* 1. What about buffered unicast traffic for our AID? */
+       cam = ieee80211_check_tim(tim_ie, tim_len, ar->common.curaid);
+
+       /* 2. Maybe the AP wants to send multicast/broadcast data? */
+       cam = !!(tim_ie->bitmap_ctrl & 0x01);
+
+       if (!cam) {
+               /* back to low-power land. */
+               ar->ps.off_override &= ~PS_OFF_BCN;
+               carl9170_ps_check(ar);
+       } else {
+               /* force CAM */
+               ar->ps.off_override |= PS_OFF_BCN;
+       }
+}
+
+static bool carl9170_ampdu_check(struct ar9170 *ar, u8 *buf, u8 ms)
+{
+       __le16 fc;
+
+       if ((ms & AR9170_RX_STATUS_MPDU) == AR9170_RX_STATUS_MPDU_SINGLE) {
+               /*
+                * This frame is not part of an aMPDU.
+                * Therefore it is not subjected to any
+                * of the following content restrictions.
+                */
+               return true;
+       }
+
+       /*
+        * "802.11n - 7.4a.3 A-MPDU contents" describes in which contexts
+        * certain frame types can be part of an aMPDU.
+        *
+        * In order to keep the processing cost down, I opted for a
+        * stateless filter solely based on the frame control field.
+        */
+
+       fc = ((struct ieee80211_hdr *)buf)->frame_control;
+       if (ieee80211_is_data_qos(fc) && ieee80211_is_data_present(fc))
+               return true;
+
+       if (ieee80211_is_ack(fc) || ieee80211_is_back(fc) ||
+           ieee80211_is_back_req(fc))
+               return true;
+
+       if (ieee80211_is_action(fc))
+               return true;
+
+       return false;
+}
+
+/*
+ * If the frame alignment is right (or the kernel has
+ * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS), and there
+ * is only a single MPDU in the USB frame, then we could
+ * submit to mac80211 the SKB directly. However, since
+ * there may be multiple packets in one SKB in stream
+ * mode, and we need to observe the proper ordering,
+ * this is non-trivial.
+ */
+
+static void carl9170_handle_mpdu(struct ar9170 *ar, u8 *buf, int len)
+{
+       struct ar9170_rx_head *head;
+       struct ar9170_rx_macstatus *mac;
+       struct ar9170_rx_phystatus *phy = NULL;
+       struct ieee80211_rx_status status;
+       struct sk_buff *skb;
+       int mpdu_len;
+       u8 mac_status;
+
+       if (!IS_STARTED(ar))
+               return;
+
+       if (unlikely(len < sizeof(*mac)))
+               goto drop;
+
+       mpdu_len = len - sizeof(*mac);
+
+       mac = (void *)(buf + mpdu_len);
+       mac_status = mac->status;
+       switch (mac_status & AR9170_RX_STATUS_MPDU) {
+       case AR9170_RX_STATUS_MPDU_FIRST:
+               /* Aggregated MPDUs start with an PLCP header */
+               if (likely(mpdu_len >= sizeof(struct ar9170_rx_head))) {
+                       head = (void *) buf;
+
+                       /*
+                        * The PLCP header needs to be cached for the
+                        * following MIDDLE + LAST A-MPDU packets.
+                        *
+                        * So, if you are wondering why all frames seem
+                        * to share a common RX status information,
+                        * then you have the answer right here...
+                        */
+                       memcpy(&ar->rx_plcp, (void *) buf,
+                              sizeof(struct ar9170_rx_head));
+
+                       mpdu_len -= sizeof(struct ar9170_rx_head);
+                       buf += sizeof(struct ar9170_rx_head);
+
+                       ar->rx_has_plcp = true;
+               } else {
+                       if (net_ratelimit()) {
+                               wiphy_err(ar->hw->wiphy, "plcp info "
+                                       "is clipped.\n");
+                       }
+
+                       goto drop;
+               }
+               break;
+
+       case AR9170_RX_STATUS_MPDU_LAST:
+               /*
+                * The last frame of an A-MPDU has an extra tail
+                * which does contain the phy status of the whole
+                * aggregate.
+                */
+
+               if (likely(mpdu_len >= sizeof(struct ar9170_rx_phystatus))) {
+                       mpdu_len -= sizeof(struct ar9170_rx_phystatus);
+                       phy = (void *)(buf + mpdu_len);
+               } else {
+                       if (net_ratelimit()) {
+                               wiphy_err(ar->hw->wiphy, "frame tail "
+                                       "is clipped.\n");
+                       }
+
+                       goto drop;
+               }
+
+       case AR9170_RX_STATUS_MPDU_MIDDLE:
+               /*  These are just data + mac status */
+               if (unlikely(!ar->rx_has_plcp)) {
+                       if (!net_ratelimit())
+                               return;
+
+                       wiphy_err(ar->hw->wiphy, "rx stream does not start "
+                                       "with a first_mpdu frame tag.\n");
+
+                       goto drop;
+               }
+
+               head = &ar->rx_plcp;
+               break;
+
+       case AR9170_RX_STATUS_MPDU_SINGLE:
+               /* single mpdu has both: plcp (head) and phy status (tail) */
+               head = (void *) buf;
+
+               mpdu_len -= sizeof(struct ar9170_rx_head);
+               mpdu_len -= sizeof(struct ar9170_rx_phystatus);
+
+               buf += sizeof(struct ar9170_rx_head);
+               phy = (void *)(buf + mpdu_len);
+               break;
+
+       default:
+               BUG_ON(1);
+               break;
+       }
+
+       /* FC + DU + RA + FCS */
+       if (unlikely(mpdu_len < (2 + 2 + ETH_ALEN + FCS_LEN)))
+               goto drop;
+
+       memset(&status, 0, sizeof(status));
+       if (unlikely(carl9170_rx_mac_status(ar, head, mac, &status)))
+               goto drop;
+
+       if (!carl9170_ampdu_check(ar, buf, mac_status))
+               goto drop;
+
+       if (phy)
+               carl9170_rx_phy_status(ar, phy, &status);
+
+       carl9170_ps_beacon(ar, buf, mpdu_len);
+
+       skb = carl9170_rx_copy_data(buf, mpdu_len);
+       if (!skb)
+               goto drop;
+
+       memcpy(IEEE80211_SKB_RXCB(skb), &status, sizeof(status));
+       ieee80211_rx(ar->hw, skb);
+       return;
+
+drop:
+       ar->rx_dropped++;
+}
+
+static void carl9170_rx_untie_cmds(struct ar9170 *ar, const u8 *respbuf,
+                                  const unsigned int resplen)
+{
+       struct carl9170_rsp *cmd;
+       int i = 0;
+
+       while (i < resplen) {
+               cmd = (void *) &respbuf[i];
+
+               i += cmd->hdr.len + 4;
+               if (unlikely(i > resplen))
+                       break;
+
+               carl9170_handle_command_response(ar, cmd, cmd->hdr.len + 4);
+       }
+
+       if (unlikely(i != resplen)) {
+               if (!net_ratelimit())
+                       return;
+
+               wiphy_err(ar->hw->wiphy, "malformed firmware trap:\n");
+               print_hex_dump_bytes("rxcmd:", DUMP_PREFIX_OFFSET,
+                                    respbuf, resplen);
+       }
+}
+
+static void __carl9170_rx(struct ar9170 *ar, u8 *buf, unsigned int len)
+{
+       unsigned int i = 0;
+
+       /* weird thing, but this is the same in the original driver */
+       while (len > 2 && i < 12 && buf[0] == 0xff && buf[1] == 0xff) {
+               i += 2;
+               len -= 2;
+               buf += 2;
+       }
+
+       if (unlikely(len < 4))
+               return;
+
+       /* found the 6 * 0xffff marker? */
+       if (i == 12)
+               carl9170_rx_untie_cmds(ar, buf, len);
+       else
+               carl9170_handle_mpdu(ar, buf, len);
+}
+
+static void carl9170_rx_stream(struct ar9170 *ar, void *buf, unsigned int len)
+{
+       unsigned int tlen, wlen = 0, clen = 0;
+       struct ar9170_stream *rx_stream;
+       u8 *tbuf;
+
+       tbuf = buf;
+       tlen = len;
+
+       while (tlen >= 4) {
+               rx_stream = (void *) tbuf;
+               clen = le16_to_cpu(rx_stream->length);
+               wlen = ALIGN(clen, 4);
+
+               /* check if this is stream has a valid tag.*/
+               if (rx_stream->tag != cpu_to_le16(AR9170_RX_STREAM_TAG)) {
+                       /*
+                        * TODO: handle the highly unlikely event that the
+                        * corrupted stream has the TAG at the right position.
+                        */
+
+                       /* check if the frame can be repaired. */
+                       if (!ar->rx_failover_missing) {
+
+                               /* this is not "short read". */
+                               if (net_ratelimit()) {
+                                       wiphy_err(ar->hw->wiphy,
+                                               "missing tag!\n");
+                               }
+
+                               __carl9170_rx(ar, tbuf, tlen);
+                               return;
+                       }
+
+                       if (ar->rx_failover_missing > tlen) {
+                               if (net_ratelimit()) {
+                                       wiphy_err(ar->hw->wiphy,
+                                               "possible multi "
+                                               "stream corruption!\n");
+                                       goto err_telluser;
+                               } else {
+                                       goto err_silent;
+                               }
+                       }
+
+                       memcpy(skb_put(ar->rx_failover, tlen), tbuf, tlen);
+                       ar->rx_failover_missing -= tlen;
+
+                       if (ar->rx_failover_missing <= 0) {
+                               /*
+                                * nested carl9170_rx_stream call!
+                                *
+                                * termination is guranteed, even when the
+                                * combined frame also have an element with
+                                * a bad tag.
+                                */
+
+                               ar->rx_failover_missing = 0;
+                               carl9170_rx_stream(ar, ar->rx_failover->data,
+                                                  ar->rx_failover->len);
+
+                               skb_reset_tail_pointer(ar->rx_failover);
+                               skb_trim(ar->rx_failover, 0);
+                       }
+
+                       return;
+               }
+
+               /* check if stream is clipped */
+               if (wlen > tlen - 4) {
+                       if (ar->rx_failover_missing) {
+                               /* TODO: handle double stream corruption. */
+                               if (net_ratelimit()) {
+                                       wiphy_err(ar->hw->wiphy, "double rx "
+                                               "stream corruption!\n");
+                                       goto err_telluser;
+                               } else {
+                                       goto err_silent;
+                               }
+                       }
+
+                       /*
+                        * save incomplete data set.
+                        * the firmware will resend the missing bits when
+                        * the rx - descriptor comes round again.
+                        */
+
+                       memcpy(skb_put(ar->rx_failover, tlen), tbuf, tlen);
+                       ar->rx_failover_missing = clen - tlen;
+                       return;
+               }
+               __carl9170_rx(ar, rx_stream->payload, clen);
+
+               tbuf += wlen + 4;
+               tlen -= wlen + 4;
+       }
+
+       if (tlen) {
+               if (net_ratelimit()) {
+                       wiphy_err(ar->hw->wiphy, "%d bytes of unprocessed "
+                               "data left in rx stream!\n", tlen);
+               }
+
+               goto err_telluser;
+       }
+
+       return;
+
+err_telluser:
+       wiphy_err(ar->hw->wiphy, "damaged RX stream data [want:%d, "
+               "data:%d, rx:%d, pending:%d ]\n", clen, wlen, tlen,
+               ar->rx_failover_missing);
+
+       if (ar->rx_failover_missing)
+               print_hex_dump_bytes("rxbuf:", DUMP_PREFIX_OFFSET,
+                                    ar->rx_failover->data,
+                                    ar->rx_failover->len);
+
+       print_hex_dump_bytes("stream:", DUMP_PREFIX_OFFSET,
+                            buf, len);
+
+       wiphy_err(ar->hw->wiphy, "please check your hardware and cables, if "
+               "you see this message frequently.\n");
+
+err_silent:
+       if (ar->rx_failover_missing) {
+               skb_reset_tail_pointer(ar->rx_failover);
+               skb_trim(ar->rx_failover, 0);
+               ar->rx_failover_missing = 0;
+       }
+}
+
+void carl9170_rx(struct ar9170 *ar, void *buf, unsigned int len)
+{
+       if (ar->fw.rx_stream)
+               carl9170_rx_stream(ar, buf, len);
+       else
+               __carl9170_rx(ar, buf, len);
+}