drivers/net/wireless/iwlwifi/mvm/rx.c - linux - Git at Google

 /******************************************************************************
  *
  * This file is provided under a dual BSD/GPLv2 license.  When using or
  * redistributing this file, you may do so under either license.
  *
  * GPL LICENSE SUMMARY
  *
  * Copyright(c) 2012 - 2013 Intel Corporation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
  * published by the Free Software Foundation.
  *
  * 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; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110,
  * USA
  *
  * The full GNU General Public License is included in this distribution
  * in the file called LICENSE.GPL.
  *
  * Contact Information:
  *  Intel Linux Wireless <ilw@linux.intel.com>
  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
  *
  * BSD LICENSE
  *
  * Copyright(c) 2012 - 2013 Intel Corporation. All rights reserved.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *  * Neither the name Intel Corporation nor the names of its
  *    contributors may be used to endorse or promote products derived
  *    from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 #include "iwl-trans.h"

 #include "mvm.h"
 #include "fw-api.h"

 /*
  * iwl_mvm_rx_rx_phy_cmd - REPLY_RX_PHY_CMD handler
  *
  * Copies the phy information in mvm->last_phy_info, it will be used when the
  * actual data will come from the fw in the next packet.
  */
 int iwl_mvm_rx_rx_phy_cmd(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
 			  struct iwl_device_cmd *cmd)
 {
 	struct iwl_rx_packet *pkt = rxb_addr(rxb);

 	memcpy(&mvm->last_phy_info, pkt->data, sizeof(mvm->last_phy_info));
 	mvm->ampdu_ref++;
 	return 0;
 }

 /*
  * iwl_mvm_pass_packet_to_mac80211 - builds the packet for mac80211
  *
  * Adds the rxb to a new skb and give it to mac80211
  */
 static void iwl_mvm_pass_packet_to_mac80211(struct iwl_mvm *mvm,
 					    struct ieee80211_hdr *hdr, u16 len,
 					    u32 ampdu_status,
 					    struct iwl_rx_cmd_buffer *rxb,
 					    struct ieee80211_rx_status *stats)
 {
 	struct sk_buff *skb;
 	unsigned int hdrlen, fraglen;

 	/* Dont use dev_alloc_skb(), we'll have enough headroom once
 	 * ieee80211_hdr pulled.
 	 */
 	skb = alloc_skb(128, GFP_ATOMIC);
 	if (!skb) {
 		IWL_ERR(mvm, "alloc_skb failed\n");
 		return;
 	}
 	/* If frame is small enough to fit in skb->head, pull it completely.
 	 * If not, only pull ieee80211_hdr so that splice() or TCP coalesce
 	 * are more efficient.
 	 */
 	hdrlen = (len <= skb_tailroom(skb)) ? len : sizeof(*hdr);

 	memcpy(skb_put(skb, hdrlen), hdr, hdrlen);
 	fraglen = len - hdrlen;

 	if (fraglen) {
 		int offset = (void *)hdr + hdrlen -
 			     rxb_addr(rxb) + rxb_offset(rxb);

 		skb_add_rx_frag(skb, 0, rxb_steal_page(rxb), offset,
 				fraglen, rxb->truesize);
 	}

 	memcpy(IEEE80211_SKB_RXCB(skb), stats, sizeof(*stats));

 	ieee80211_rx_ni(mvm->hw, skb);
 }

 /*
  * iwl_mvm_calc_rssi - calculate the rssi in dBm
  * @phy_info: the phy information for the coming packet
  */
 static int iwl_mvm_calc_rssi(struct iwl_mvm *mvm,
 			     struct iwl_rx_phy_info *phy_info)
 {
 	int rssi_a, rssi_b, rssi_a_dbm, rssi_b_dbm, max_rssi_dbm;
 	int rssi_all_band_a, rssi_all_band_b;
 	u32 agc_a, agc_b, max_agc;
 	u32 val;

 	/* Find max rssi among 2 possible receivers.
 	 * These values are measured by the Digital Signal Processor (DSP).
 	 * They should stay fairly constant even as the signal strength varies,
 	 * if the radio's Automatic Gain Control (AGC) is working right.
 	 * AGC value (see below) will provide the "interesting" info.
 	 */
 	val = le32_to_cpu(phy_info->non_cfg_phy[IWL_RX_INFO_AGC_IDX]);
 	agc_a = (val & IWL_OFDM_AGC_A_MSK) >> IWL_OFDM_AGC_A_POS;
 	agc_b = (val & IWL_OFDM_AGC_B_MSK) >> IWL_OFDM_AGC_B_POS;
 	max_agc = max_t(u32, agc_a, agc_b);

 	val = le32_to_cpu(phy_info->non_cfg_phy[IWL_RX_INFO_RSSI_AB_IDX]);
 	rssi_a = (val & IWL_OFDM_RSSI_INBAND_A_MSK) >> IWL_OFDM_RSSI_A_POS;
 	rssi_b = (val & IWL_OFDM_RSSI_INBAND_B_MSK) >> IWL_OFDM_RSSI_B_POS;
 	rssi_all_band_a = (val & IWL_OFDM_RSSI_ALLBAND_A_MSK) >>
 				IWL_OFDM_RSSI_ALLBAND_A_POS;
 	rssi_all_band_b = (val & IWL_OFDM_RSSI_ALLBAND_B_MSK) >>
 				IWL_OFDM_RSSI_ALLBAND_B_POS;

 	/*
 	 * dBm = rssi dB - agc dB - constant.
 	 * Higher AGC (higher radio gain) means lower signal.
 	 */
 	rssi_a_dbm = rssi_a - IWL_RSSI_OFFSET - agc_a;
 	rssi_b_dbm = rssi_b - IWL_RSSI_OFFSET - agc_b;
 	max_rssi_dbm = max_t(int, rssi_a_dbm, rssi_b_dbm);

 	IWL_DEBUG_STATS(mvm, "Rssi In A %d B %d Max %d AGCA %d AGCB %d\n",
 			rssi_a_dbm, rssi_b_dbm, max_rssi_dbm, agc_a, agc_b);

 	return max_rssi_dbm;
 }

 /*
  * iwl_mvm_set_mac80211_rx_flag - translate fw status to mac80211 format
  * @mvm: the mvm object
  * @hdr: 80211 header
  * @stats: status in mac80211's format
  * @rx_pkt_status: status coming from fw
  *
  * returns non 0 value if the packet should be dropped
  */
 static u32 iwl_mvm_set_mac80211_rx_flag(struct iwl_mvm *mvm,
 					struct ieee80211_hdr *hdr,
 					struct ieee80211_rx_status *stats,
 					u32 rx_pkt_status)
 {
 	if (!ieee80211_has_protected(hdr->frame_control) ||
 	    (rx_pkt_status & RX_MPDU_RES_STATUS_SEC_ENC_MSK) ==
 			     RX_MPDU_RES_STATUS_SEC_NO_ENC)
 		return 0;

 	/* packet was encrypted with unknown alg */
 	if ((rx_pkt_status & RX_MPDU_RES_STATUS_SEC_ENC_MSK) ==
 					RX_MPDU_RES_STATUS_SEC_ENC_ERR)
 		return 0;

 	switch (rx_pkt_status & RX_MPDU_RES_STATUS_SEC_ENC_MSK) {
 	case RX_MPDU_RES_STATUS_SEC_CCM_ENC:
 		/* alg is CCM: check MIC only */
 		if (!(rx_pkt_status & RX_MPDU_RES_STATUS_MIC_OK))
 			return -1;

 		stats->flag |= RX_FLAG_DECRYPTED;
 		IWL_DEBUG_WEP(mvm, "hw decrypted CCMP successfully\n");
 		return 0;

 	case RX_MPDU_RES_STATUS_SEC_TKIP_ENC:
 		/* Don't drop the frame and decrypt it in SW */
 		if (!(rx_pkt_status & RX_MPDU_RES_STATUS_TTAK_OK))
 			return 0;
 		/* fall through if TTAK OK */

 	case RX_MPDU_RES_STATUS_SEC_WEP_ENC:
 		if (!(rx_pkt_status & RX_MPDU_RES_STATUS_ICV_OK))
 			return -1;

 		stats->flag |= RX_FLAG_DECRYPTED;
 		return 0;

 	default:
 		IWL_ERR(mvm, "Unhandled alg: 0x%x\n", rx_pkt_status);
 	}

 	return 0;
 }

 /*
  * iwl_mvm_rx_rx_mpdu - REPLY_RX_MPDU_CMD handler
  *
  * Handles the actual data of the Rx packet from the fw
  */
 int iwl_mvm_rx_rx_mpdu(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
 		       struct iwl_device_cmd *cmd)
 {
 	struct ieee80211_hdr *hdr;
 	struct ieee80211_rx_status rx_status = {};
 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
 	struct iwl_rx_phy_info *phy_info;
 	struct iwl_rx_mpdu_res_start *rx_res;
 	u32 len;
 	u32 ampdu_status;
 	u32 rate_n_flags;
 	u32 rx_pkt_status;

 	phy_info = &mvm->last_phy_info;
 	rx_res = (struct iwl_rx_mpdu_res_start *)pkt->data;
 	hdr = (struct ieee80211_hdr *)(pkt->data + sizeof(*rx_res));
 	len = le16_to_cpu(rx_res->byte_count);
 	rx_pkt_status = le32_to_cpup((__le32 *)
 		(pkt->data + sizeof(*rx_res) + len));

 	memset(&rx_status, 0, sizeof(rx_status));

 	/*
 	 * drop the packet if it has failed being decrypted by HW
 	 */
 	if (iwl_mvm_set_mac80211_rx_flag(mvm, hdr, &rx_status, rx_pkt_status)) {
 		IWL_DEBUG_DROP(mvm, "Bad decryption results 0x%08x\n",
 			       rx_pkt_status);
 		return 0;
 	}

 	if ((unlikely(phy_info->cfg_phy_cnt > 20))) {
 		IWL_DEBUG_DROP(mvm, "dsp size out of range [0,20]: %d\n",
 			       phy_info->cfg_phy_cnt);
 		return 0;
 	}

 	if (!(rx_pkt_status & RX_MPDU_RES_STATUS_CRC_OK) ||
 	    !(rx_pkt_status & RX_MPDU_RES_STATUS_OVERRUN_OK)) {
 		IWL_DEBUG_RX(mvm, "Bad CRC or FIFO: 0x%08X.\n", rx_pkt_status);
 		return 0;
 	}

 	/* This will be used in several places later */
 	rate_n_flags = le32_to_cpu(phy_info->rate_n_flags);

 	/* rx_status carries information about the packet to mac80211 */
 	rx_status.mactime = le64_to_cpu(phy_info->timestamp);
 	rx_status.device_timestamp = le32_to_cpu(phy_info->system_timestamp);
 	rx_status.band =
 		(phy_info->phy_flags & cpu_to_le16(RX_RES_PHY_FLAGS_BAND_24)) ?
 				IEEE80211_BAND_2GHZ : IEEE80211_BAND_5GHZ;
 	rx_status.freq =
 		ieee80211_channel_to_frequency(le16_to_cpu(phy_info->channel),
 					       rx_status.band);
 	/*
 	 * TSF as indicated by the fw is at INA time, but mac80211 expects the
 	 * TSF at the beginning of the MPDU.
 	 */
 	/*rx_status.flag |= RX_FLAG_MACTIME_MPDU;*/

 	/* Find max signal strength (dBm) among 3 antenna/receiver chains */
 	rx_status.signal = iwl_mvm_calc_rssi(mvm, phy_info);

 	IWL_DEBUG_STATS_LIMIT(mvm, "Rssi %d, TSF %llu\n", rx_status.signal,
 			      (unsigned long long)rx_status.mactime);

 	/*
 	 * "antenna number"
 	 *
 	 * It seems that the antenna field in the phy flags value
 	 * is actually a bit field. This is undefined by radiotap,
 	 * it wants an actual antenna number but I always get "7"
 	 * for most legacy frames I receive indicating that the
 	 * same frame was received on all three RX chains.
 	 *
 	 * I think this field should be removed in favor of a
 	 * new 802.11n radiotap field "RX chains" that is defined
 	 * as a bitmask.
 	 */
 	rx_status.antenna = (le16_to_cpu(phy_info->phy_flags) &
 				RX_RES_PHY_FLAGS_ANTENNA)
 				>> RX_RES_PHY_FLAGS_ANTENNA_POS;

 	/* set the preamble flag if appropriate */
 	if (phy_info->phy_flags & cpu_to_le16(RX_RES_PHY_FLAGS_SHORT_PREAMBLE))
 		rx_status.flag |= RX_FLAG_SHORTPRE;

 	if (phy_info->phy_flags & cpu_to_le16(RX_RES_PHY_FLAGS_AGG)) {
 		/*
 		 * We know which subframes of an A-MPDU belong
 		 * together since we get a single PHY response
 		 * from the firmware for all of them
 		 */
 		rx_status.flag |= RX_FLAG_AMPDU_DETAILS;
 		rx_status.ampdu_reference = mvm->ampdu_ref;
 	}

 	/* Set up the HT phy flags */
 	switch (rate_n_flags & RATE_MCS_CHAN_WIDTH_MSK) {
 	case RATE_MCS_CHAN_WIDTH_20:
 		break;
 	case RATE_MCS_CHAN_WIDTH_40:
 		rx_status.flag |= RX_FLAG_40MHZ;
 		break;
 	case RATE_MCS_CHAN_WIDTH_80:
 		rx_status.flag |= RX_FLAG_80MHZ;
 		break;
 	case RATE_MCS_CHAN_WIDTH_160:
 		rx_status.flag |= RX_FLAG_160MHZ;
 		break;
 	}
 	if (rate_n_flags & RATE_MCS_SGI_MSK)
 		rx_status.flag |= RX_FLAG_SHORT_GI;
 	if (rate_n_flags & RATE_HT_MCS_GF_MSK)
 		rx_status.flag |= RX_FLAG_HT_GF;
 	if (rate_n_flags & RATE_MCS_HT_MSK) {
 		rx_status.flag |= RX_FLAG_HT;
 		rx_status.rate_idx = rate_n_flags & RATE_HT_MCS_INDEX_MSK;
 	} else if (rate_n_flags & RATE_MCS_VHT_MSK) {
 		rx_status.vht_nss =
 			((rate_n_flags & RATE_VHT_MCS_NSS_MSK) >>
 						RATE_VHT_MCS_NSS_POS) + 1;
 		rx_status.rate_idx = rate_n_flags & RATE_VHT_MCS_RATE_CODE_MSK;
 		rx_status.flag |= RX_FLAG_VHT;
 	} else {
 		rx_status.rate_idx =
 			iwl_mvm_legacy_rate_to_mac80211_idx(rate_n_flags,
 							    rx_status.band);
 	}

 	iwl_mvm_pass_packet_to_mac80211(mvm, hdr, len, ampdu_status,
 					rxb, &rx_status);
 	return 0;
 }
	/******************************************************************************
	*
	* This file is provided under a dual BSD/GPLv2 license. When using or
	* redistributing this file, you may do so under either license.
	*
	* GPL LICENSE SUMMARY
	*
	* Copyright(c) 2012 - 2013 Intel Corporation. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of version 2 of the GNU General Public License as
	* published by the Free Software Foundation.
	*
	* 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; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110,
	* USA
	*
	* The full GNU General Public License is included in this distribution
	* in the file called LICENSE.GPL.
	*
	* Contact Information:
	* Intel Linux Wireless <ilw@linux.intel.com>
	* Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
	*
	* BSD LICENSE
	*
	* Copyright(c) 2012 - 2013 Intel Corporation. All rights reserved.
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name Intel Corporation nor the names of its
	* contributors may be used to endorse or promote products derived
	* from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*****************************************************************************/
	#include "iwl-trans.h"

	#include "mvm.h"
	#include "fw-api.h"

	/*
	* iwl_mvm_rx_rx_phy_cmd - REPLY_RX_PHY_CMD handler
	*
	* Copies the phy information in mvm->last_phy_info, it will be used when the
	* actual data will come from the fw in the next packet.
	*/
	int iwl_mvm_rx_rx_phy_cmd(struct iwl_mvm mvm, struct iwl_rx_cmd_buffer rxb,
	struct iwl_device_cmd *cmd)
	{
	struct iwl_rx_packet *pkt = rxb_addr(rxb);

	memcpy(&mvm->last_phy_info, pkt->data, sizeof(mvm->last_phy_info));
	mvm->ampdu_ref++;
	return 0;
	}

	/*
	* iwl_mvm_pass_packet_to_mac80211 - builds the packet for mac80211
	*
	* Adds the rxb to a new skb and give it to mac80211
	*/
	static void iwl_mvm_pass_packet_to_mac80211(struct iwl_mvm *mvm,
	struct ieee80211_hdr *hdr, u16 len,
	u32 ampdu_status,
	struct iwl_rx_cmd_buffer *rxb,
	struct ieee80211_rx_status *stats)
	{
	struct sk_buff *skb;
	unsigned int hdrlen, fraglen;

	/* Dont use dev_alloc_skb(), we'll have enough headroom once
	* ieee80211_hdr pulled.
	*/
	skb = alloc_skb(128, GFP_ATOMIC);
	if (!skb) {
	IWL_ERR(mvm, "alloc_skb failed\n");
	return;
	}
	/* If frame is small enough to fit in skb->head, pull it completely.
	* If not, only pull ieee80211_hdr so that splice() or TCP coalesce
	* are more efficient.
	*/
	hdrlen = (len <= skb_tailroom(skb)) ? len : sizeof(*hdr);

	memcpy(skb_put(skb, hdrlen), hdr, hdrlen);
	fraglen = len - hdrlen;

	if (fraglen) {
	int offset = (void *)hdr + hdrlen -
	rxb_addr(rxb) + rxb_offset(rxb);

	skb_add_rx_frag(skb, 0, rxb_steal_page(rxb), offset,
	fraglen, rxb->truesize);
	}

	memcpy(IEEE80211_SKB_RXCB(skb), stats, sizeof(*stats));

	ieee80211_rx_ni(mvm->hw, skb);
	}

	/*
	* iwl_mvm_calc_rssi - calculate the rssi in dBm
	* @phy_info: the phy information for the coming packet
	*/
	static int iwl_mvm_calc_rssi(struct iwl_mvm *mvm,
	struct iwl_rx_phy_info *phy_info)
	{
	int rssi_a, rssi_b, rssi_a_dbm, rssi_b_dbm, max_rssi_dbm;
	int rssi_all_band_a, rssi_all_band_b;
	u32 agc_a, agc_b, max_agc;
	u32 val;

	/* Find max rssi among 2 possible receivers.
	* These values are measured by the Digital Signal Processor (DSP).
	* They should stay fairly constant even as the signal strength varies,
	* if the radio's Automatic Gain Control (AGC) is working right.
	* AGC value (see below) will provide the "interesting" info.
	*/
	val = le32_to_cpu(phy_info->non_cfg_phy[IWL_RX_INFO_AGC_IDX]);
	agc_a = (val & IWL_OFDM_AGC_A_MSK) >> IWL_OFDM_AGC_A_POS;
	agc_b = (val & IWL_OFDM_AGC_B_MSK) >> IWL_OFDM_AGC_B_POS;
	max_agc = max_t(u32, agc_a, agc_b);

	val = le32_to_cpu(phy_info->non_cfg_phy[IWL_RX_INFO_RSSI_AB_IDX]);
	rssi_a = (val & IWL_OFDM_RSSI_INBAND_A_MSK) >> IWL_OFDM_RSSI_A_POS;
	rssi_b = (val & IWL_OFDM_RSSI_INBAND_B_MSK) >> IWL_OFDM_RSSI_B_POS;
	rssi_all_band_a = (val & IWL_OFDM_RSSI_ALLBAND_A_MSK) >>
	IWL_OFDM_RSSI_ALLBAND_A_POS;
	rssi_all_band_b = (val & IWL_OFDM_RSSI_ALLBAND_B_MSK) >>
	IWL_OFDM_RSSI_ALLBAND_B_POS;

	/*
	* dBm = rssi dB - agc dB - constant.
	* Higher AGC (higher radio gain) means lower signal.
	*/
	rssi_a_dbm = rssi_a - IWL_RSSI_OFFSET - agc_a;
	rssi_b_dbm = rssi_b - IWL_RSSI_OFFSET - agc_b;
	max_rssi_dbm = max_t(int, rssi_a_dbm, rssi_b_dbm);

	IWL_DEBUG_STATS(mvm, "Rssi In A %d B %d Max %d AGCA %d AGCB %d\n",
	rssi_a_dbm, rssi_b_dbm, max_rssi_dbm, agc_a, agc_b);

	return max_rssi_dbm;
	}

	/*
	* iwl_mvm_set_mac80211_rx_flag - translate fw status to mac80211 format
	* @mvm: the mvm object
	* @hdr: 80211 header
	* @stats: status in mac80211's format
	* @rx_pkt_status: status coming from fw
	*
	* returns non 0 value if the packet should be dropped
	*/
	static u32 iwl_mvm_set_mac80211_rx_flag(struct iwl_mvm *mvm,
	struct ieee80211_hdr *hdr,
	struct ieee80211_rx_status *stats,
	u32 rx_pkt_status)
	{
	if (!ieee80211_has_protected(hdr->frame_control) \|\|
	(rx_pkt_status & RX_MPDU_RES_STATUS_SEC_ENC_MSK) ==
	RX_MPDU_RES_STATUS_SEC_NO_ENC)
	return 0;

	/* packet was encrypted with unknown alg */
	if ((rx_pkt_status & RX_MPDU_RES_STATUS_SEC_ENC_MSK) ==
	RX_MPDU_RES_STATUS_SEC_ENC_ERR)
	return 0;

	switch (rx_pkt_status & RX_MPDU_RES_STATUS_SEC_ENC_MSK) {
	case RX_MPDU_RES_STATUS_SEC_CCM_ENC:
	/* alg is CCM: check MIC only */
	if (!(rx_pkt_status & RX_MPDU_RES_STATUS_MIC_OK))
	return -1;

	stats->flag \|= RX_FLAG_DECRYPTED;
	IWL_DEBUG_WEP(mvm, "hw decrypted CCMP successfully\n");
	return 0;

	case RX_MPDU_RES_STATUS_SEC_TKIP_ENC:
	/* Don't drop the frame and decrypt it in SW */
	if (!(rx_pkt_status & RX_MPDU_RES_STATUS_TTAK_OK))
	return 0;
	/* fall through if TTAK OK */

	case RX_MPDU_RES_STATUS_SEC_WEP_ENC:
	if (!(rx_pkt_status & RX_MPDU_RES_STATUS_ICV_OK))
	return -1;

	stats->flag \|= RX_FLAG_DECRYPTED;
	return 0;

	default:
	IWL_ERR(mvm, "Unhandled alg: 0x%x\n", rx_pkt_status);
	}

	return 0;
	}

	/*
	* iwl_mvm_rx_rx_mpdu - REPLY_RX_MPDU_CMD handler
	*
	* Handles the actual data of the Rx packet from the fw
	*/
	int iwl_mvm_rx_rx_mpdu(struct iwl_mvm mvm, struct iwl_rx_cmd_buffer rxb,
	struct iwl_device_cmd *cmd)
	{
	struct ieee80211_hdr *hdr;
	struct ieee80211_rx_status rx_status = {};
	struct iwl_rx_packet *pkt = rxb_addr(rxb);
	struct iwl_rx_phy_info *phy_info;
	struct iwl_rx_mpdu_res_start *rx_res;
	u32 len;
	u32 ampdu_status;
	u32 rate_n_flags;
	u32 rx_pkt_status;

	phy_info = &mvm->last_phy_info;
	rx_res = (struct iwl_rx_mpdu_res_start *)pkt->data;
	hdr = (struct ieee80211_hdr )(pkt->data + sizeof(rx_res));
	len = le16_to_cpu(rx_res->byte_count);
	rx_pkt_status = le32_to_cpup((__le32 *)
	(pkt->data + sizeof(*rx_res) + len));

	memset(&rx_status, 0, sizeof(rx_status));

	/*
	* drop the packet if it has failed being decrypted by HW
	*/
	if (iwl_mvm_set_mac80211_rx_flag(mvm, hdr, &rx_status, rx_pkt_status)) {
	IWL_DEBUG_DROP(mvm, "Bad decryption results 0x%08x\n",
	rx_pkt_status);
	return 0;
	}

	if ((unlikely(phy_info->cfg_phy_cnt > 20))) {
	IWL_DEBUG_DROP(mvm, "dsp size out of range [0,20]: %d\n",
	phy_info->cfg_phy_cnt);
	return 0;
	}

	if (!(rx_pkt_status & RX_MPDU_RES_STATUS_CRC_OK) \|\|
	!(rx_pkt_status & RX_MPDU_RES_STATUS_OVERRUN_OK)) {
	IWL_DEBUG_RX(mvm, "Bad CRC or FIFO: 0x%08X.\n", rx_pkt_status);
	return 0;
	}

	/* This will be used in several places later */
	rate_n_flags = le32_to_cpu(phy_info->rate_n_flags);

	/* rx_status carries information about the packet to mac80211 */
	rx_status.mactime = le64_to_cpu(phy_info->timestamp);
	rx_status.device_timestamp = le32_to_cpu(phy_info->system_timestamp);
	rx_status.band =
	(phy_info->phy_flags & cpu_to_le16(RX_RES_PHY_FLAGS_BAND_24)) ?
	IEEE80211_BAND_2GHZ : IEEE80211_BAND_5GHZ;
	rx_status.freq =
	ieee80211_channel_to_frequency(le16_to_cpu(phy_info->channel),
	rx_status.band);
	/*
	* TSF as indicated by the fw is at INA time, but mac80211 expects the
	* TSF at the beginning of the MPDU.
	*/
	/rx_status.flag \|= RX_FLAG_MACTIME_MPDU;/

	/* Find max signal strength (dBm) among 3 antenna/receiver chains */
	rx_status.signal = iwl_mvm_calc_rssi(mvm, phy_info);

	IWL_DEBUG_STATS_LIMIT(mvm, "Rssi %d, TSF %llu\n", rx_status.signal,
	(unsigned long long)rx_status.mactime);

	/*
	* "antenna number"
	*
	* It seems that the antenna field in the phy flags value
	* is actually a bit field. This is undefined by radiotap,
	* it wants an actual antenna number but I always get "7"
	* for most legacy frames I receive indicating that the
	* same frame was received on all three RX chains.
	*
	* I think this field should be removed in favor of a
	* new 802.11n radiotap field "RX chains" that is defined
	* as a bitmask.
	*/
	rx_status.antenna = (le16_to_cpu(phy_info->phy_flags) &
	RX_RES_PHY_FLAGS_ANTENNA)
	>> RX_RES_PHY_FLAGS_ANTENNA_POS;

	/* set the preamble flag if appropriate */
	if (phy_info->phy_flags & cpu_to_le16(RX_RES_PHY_FLAGS_SHORT_PREAMBLE))
	rx_status.flag \|= RX_FLAG_SHORTPRE;

	if (phy_info->phy_flags & cpu_to_le16(RX_RES_PHY_FLAGS_AGG)) {
	/*
	* We know which subframes of an A-MPDU belong
	* together since we get a single PHY response
	* from the firmware for all of them
	*/
	rx_status.flag \|= RX_FLAG_AMPDU_DETAILS;
	rx_status.ampdu_reference = mvm->ampdu_ref;
	}

	/* Set up the HT phy flags */
	switch (rate_n_flags & RATE_MCS_CHAN_WIDTH_MSK) {
	case RATE_MCS_CHAN_WIDTH_20:
	break;
	case RATE_MCS_CHAN_WIDTH_40:
	rx_status.flag \|= RX_FLAG_40MHZ;
	break;
	case RATE_MCS_CHAN_WIDTH_80:
	rx_status.flag \|= RX_FLAG_80MHZ;
	break;
	case RATE_MCS_CHAN_WIDTH_160:
	rx_status.flag \|= RX_FLAG_160MHZ;
	break;
	}
	if (rate_n_flags & RATE_MCS_SGI_MSK)
	rx_status.flag \|= RX_FLAG_SHORT_GI;
	if (rate_n_flags & RATE_HT_MCS_GF_MSK)
	rx_status.flag \|= RX_FLAG_HT_GF;
	if (rate_n_flags & RATE_MCS_HT_MSK) {
	rx_status.flag \|= RX_FLAG_HT;
	rx_status.rate_idx = rate_n_flags & RATE_HT_MCS_INDEX_MSK;
	} else if (rate_n_flags & RATE_MCS_VHT_MSK) {
	rx_status.vht_nss =
	((rate_n_flags & RATE_VHT_MCS_NSS_MSK) >>
	RATE_VHT_MCS_NSS_POS) + 1;
	rx_status.rate_idx = rate_n_flags & RATE_VHT_MCS_RATE_CODE_MSK;
	rx_status.flag \|= RX_FLAG_VHT;
	} else {
	rx_status.rate_idx =
	iwl_mvm_legacy_rate_to_mac80211_idx(rate_n_flags,
	rx_status.band);
	}

	iwl_mvm_pass_packet_to_mac80211(mvm, hdr, len, ampdu_status,
	rxb, &rx_status);
	return 0;
	}