iwlwifi: HW dependent run time calibration

This patch does several things:

1) rename CONFIG_IWL4965_SENSITIVITY to IWL4965_RUN_TIME_CALIB which is
   better semantic
2) move all the run time calibration to a new file: iwl-calib.c
3) simplify the sensitivity calibration flow and make it HW dependent
4) make the chain noise calibration flow HW dependent

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 778 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-calib.c b/drivers/net/wireless/iwlwifi/iwl-calib.c
new file mode 100644
index 000000000000..16213b05ed93
--- /dev/null
+++ b/drivers/net/wireless/iwlwifi/iwl-calib.c
@@ -0,0 +1,778 @@
+/******************************************************************************
+ *
+ * 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) 2008 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:
+ * Tomas Winkler <tomas.winkler@intel.com>
+ * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
+ *
+ * BSD LICENSE
+ *
+ * Copyright(c) 2005 - 2008 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 <linux/kernel.h>
+#include <net/mac80211.h>
+
+#include "iwl-4965.h"
+#include "iwl-core.h"
+#include "iwl-calib.h"
+#include "iwl-eeprom.h"
+
+/* "false alarms" are signals that our DSP tries to lock onto,
+ *   but then determines that they are either noise, or transmissions
+ *   from a distant wireless network (also "noise", really) that get
+ *   "stepped on" by stronger transmissions within our own network.
+ * This algorithm attempts to set a sensitivity level that is high
+ *   enough to receive all of our own network traffic, but not so
+ *   high that our DSP gets too busy trying to lock onto non-network
+ *   activity/noise. */
+static int iwl_sens_energy_cck(struct iwl_priv *priv,
+				   u32 norm_fa,
+				   u32 rx_enable_time,
+				   struct statistics_general_data *rx_info)
+{
+	u32 max_nrg_cck = 0;
+	int i = 0;
+	u8 max_silence_rssi = 0;
+	u32 silence_ref = 0;
+	u8 silence_rssi_a = 0;
+	u8 silence_rssi_b = 0;
+	u8 silence_rssi_c = 0;
+	u32 val;
+
+	/* "false_alarms" values below are cross-multiplications to assess the
+	 *   numbers of false alarms within the measured period of actual Rx
+	 *   (Rx is off when we're txing), vs the min/max expected false alarms
+	 *   (some should be expected if rx is sensitive enough) in a
+	 *   hypothetical listening period of 200 time units (TU), 204.8 msec:
+	 *
+	 * MIN_FA/fixed-time < false_alarms/actual-rx-time < MAX_FA/beacon-time
+	 *
+	 * */
+	u32 false_alarms = norm_fa * 200 * 1024;
+	u32 max_false_alarms = MAX_FA_CCK * rx_enable_time;
+	u32 min_false_alarms = MIN_FA_CCK * rx_enable_time;
+	struct iwl_sensitivity_data *data = NULL;
+	const struct iwl_sensitivity_ranges *ranges = priv->hw_params.sens;
+
+	data = &(priv->sensitivity_data);
+
+	data->nrg_auto_corr_silence_diff = 0;
+
+	/* Find max silence rssi among all 3 receivers.
+	 * This is background noise, which may include transmissions from other
+	 *    networks, measured during silence before our network's beacon */
+	silence_rssi_a = (u8)((rx_info->beacon_silence_rssi_a &
+			    ALL_BAND_FILTER) >> 8);
+	silence_rssi_b = (u8)((rx_info->beacon_silence_rssi_b &
+			    ALL_BAND_FILTER) >> 8);
+	silence_rssi_c = (u8)((rx_info->beacon_silence_rssi_c &
+			    ALL_BAND_FILTER) >> 8);
+
+	val = max(silence_rssi_b, silence_rssi_c);
+	max_silence_rssi = max(silence_rssi_a, (u8) val);
+
+	/* Store silence rssi in 20-beacon history table */
+	data->nrg_silence_rssi[data->nrg_silence_idx] = max_silence_rssi;
+	data->nrg_silence_idx++;
+	if (data->nrg_silence_idx >= NRG_NUM_PREV_STAT_L)
+		data->nrg_silence_idx = 0;
+
+	/* Find max silence rssi across 20 beacon history */
+	for (i = 0; i < NRG_NUM_PREV_STAT_L; i++) {
+		val = data->nrg_silence_rssi[i];
+		silence_ref = max(silence_ref, val);
+	}
+	IWL_DEBUG_CALIB("silence a %u, b %u, c %u, 20-bcn max %u\n",
+			silence_rssi_a, silence_rssi_b, silence_rssi_c,
+			silence_ref);
+
+	/* Find max rx energy (min value!) among all 3 receivers,
+	 *   measured during beacon frame.
+	 * Save it in 10-beacon history table. */
+	i = data->nrg_energy_idx;
+	val = min(rx_info->beacon_energy_b, rx_info->beacon_energy_c);
+	data->nrg_value[i] = min(rx_info->beacon_energy_a, val);
+
+	data->nrg_energy_idx++;
+	if (data->nrg_energy_idx >= 10)
+		data->nrg_energy_idx = 0;
+
+	/* Find min rx energy (max value) across 10 beacon history.
+	 * This is the minimum signal level that we want to receive well.
+	 * Add backoff (margin so we don't miss slightly lower energy frames).
+	 * This establishes an upper bound (min value) for energy threshold. */
+	max_nrg_cck = data->nrg_value[0];
+	for (i = 1; i < 10; i++)
+		max_nrg_cck = (u32) max(max_nrg_cck, (data->nrg_value[i]));
+	max_nrg_cck += 6;
+
+	IWL_DEBUG_CALIB("rx energy a %u, b %u, c %u, 10-bcn max/min %u\n",
+			rx_info->beacon_energy_a, rx_info->beacon_energy_b,
+			rx_info->beacon_energy_c, max_nrg_cck - 6);
+
+	/* Count number of consecutive beacons with fewer-than-desired
+	 *   false alarms. */
+	if (false_alarms < min_false_alarms)
+		data->num_in_cck_no_fa++;
+	else
+		data->num_in_cck_no_fa = 0;
+	IWL_DEBUG_CALIB("consecutive bcns with few false alarms = %u\n",
+			data->num_in_cck_no_fa);
+
+	/* If we got too many false alarms this time, reduce sensitivity */
+	if ((false_alarms > max_false_alarms) &&
+		(data->auto_corr_cck > AUTO_CORR_MAX_TH_CCK)) {
+		IWL_DEBUG_CALIB("norm FA %u > max FA %u\n",
+		     false_alarms, max_false_alarms);
+		IWL_DEBUG_CALIB("... reducing sensitivity\n");
+		data->nrg_curr_state = IWL_FA_TOO_MANY;
+		/* Store for "fewer than desired" on later beacon */
+		data->nrg_silence_ref = silence_ref;
+
+		/* increase energy threshold (reduce nrg value)
+		 *   to decrease sensitivity */
+		if (data->nrg_th_cck >
+			(ranges->max_nrg_cck + NRG_STEP_CCK))
+			data->nrg_th_cck = data->nrg_th_cck
+						 - NRG_STEP_CCK;
+		else
+			data->nrg_th_cck = ranges->max_nrg_cck;
+	/* Else if we got fewer than desired, increase sensitivity */
+	} else if (false_alarms < min_false_alarms) {
+		data->nrg_curr_state = IWL_FA_TOO_FEW;
+
+		/* Compare silence level with silence level for most recent
+		 *   healthy number or too many false alarms */
+		data->nrg_auto_corr_silence_diff = (s32)data->nrg_silence_ref -
+						   (s32)silence_ref;
+
+		IWL_DEBUG_CALIB("norm FA %u < min FA %u, silence diff %d\n",
+			 false_alarms, min_false_alarms,
+			 data->nrg_auto_corr_silence_diff);
+
+		/* Increase value to increase sensitivity, but only if:
+		 * 1a) previous beacon did *not* have *too many* false alarms
+		 * 1b) AND there's a significant difference in Rx levels
+		 *      from a previous beacon with too many, or healthy # FAs
+		 * OR 2) We've seen a lot of beacons (100) with too few
+		 *       false alarms */
+		if ((data->nrg_prev_state != IWL_FA_TOO_MANY) &&
+			((data->nrg_auto_corr_silence_diff > NRG_DIFF) ||
+			(data->num_in_cck_no_fa > MAX_NUMBER_CCK_NO_FA))) {
+
+			IWL_DEBUG_CALIB("... increasing sensitivity\n");
+			/* Increase nrg value to increase sensitivity */
+			val = data->nrg_th_cck + NRG_STEP_CCK;
+			data->nrg_th_cck = min((u32)ranges->min_nrg_cck, val);
+		} else {
+			IWL_DEBUG_CALIB("... but not changing sensitivity\n");
+		}
+
+	/* Else we got a healthy number of false alarms, keep status quo */
+	} else {
+		IWL_DEBUG_CALIB(" FA in safe zone\n");
+		data->nrg_curr_state = IWL_FA_GOOD_RANGE;
+
+		/* Store for use in "fewer than desired" with later beacon */
+		data->nrg_silence_ref = silence_ref;
+
+		/* If previous beacon had too many false alarms,
+		 *   give it some extra margin by reducing sensitivity again
+		 *   (but don't go below measured energy of desired Rx) */
+		if (IWL_FA_TOO_MANY == data->nrg_prev_state) {
+			IWL_DEBUG_CALIB("... increasing margin\n");
+			if (data->nrg_th_cck > (max_nrg_cck + NRG_MARGIN))
+				data->nrg_th_cck -= NRG_MARGIN;
+			else
+				data->nrg_th_cck = max_nrg_cck;
+		}
+	}
+
+	/* Make sure the energy threshold does not go above the measured
+	 * energy of the desired Rx signals (reduced by backoff margin),
+	 * or else we might start missing Rx frames.
+	 * Lower value is higher energy, so we use max()!
+	 */
+	data->nrg_th_cck = max(max_nrg_cck, data->nrg_th_cck);
+	IWL_DEBUG_CALIB("new nrg_th_cck %u\n", data->nrg_th_cck);
+
+	data->nrg_prev_state = data->nrg_curr_state;
+
+	/* Auto-correlation CCK algorithm */
+	if (false_alarms > min_false_alarms) {
+
+		/* increase auto_corr values to decrease sensitivity
+		 * so the DSP won't be disturbed by the noise
+		 */
+		if (data->auto_corr_cck < AUTO_CORR_MAX_TH_CCK)
+			data->auto_corr_cck = AUTO_CORR_MAX_TH_CCK + 1;
+		else {
+			val = data->auto_corr_cck + AUTO_CORR_STEP_CCK;
+			data->auto_corr_cck =
+				min((u32)ranges->auto_corr_max_cck, val);
+		}
+		val = data->auto_corr_cck_mrc + AUTO_CORR_STEP_CCK;
+		data->auto_corr_cck_mrc =
+			min((u32)ranges->auto_corr_max_cck_mrc, val);
+	} else if ((false_alarms < min_false_alarms) &&
+	   ((data->nrg_auto_corr_silence_diff > NRG_DIFF) ||
+	   (data->num_in_cck_no_fa > MAX_NUMBER_CCK_NO_FA))) {
+
+		/* Decrease auto_corr values to increase sensitivity */
+		val = data->auto_corr_cck - AUTO_CORR_STEP_CCK;
+		data->auto_corr_cck =
+			max((u32)ranges->auto_corr_min_cck, val);
+		val = data->auto_corr_cck_mrc - AUTO_CORR_STEP_CCK;
+		data->auto_corr_cck_mrc =
+			max((u32)ranges->auto_corr_min_cck_mrc, val);
+	}
+
+	return 0;
+}
+
+
+static int iwl_sens_auto_corr_ofdm(struct iwl_priv *priv,
+				       u32 norm_fa,
+				       u32 rx_enable_time)
+{
+	u32 val;
+	u32 false_alarms = norm_fa * 200 * 1024;
+	u32 max_false_alarms = MAX_FA_OFDM * rx_enable_time;
+	u32 min_false_alarms = MIN_FA_OFDM * rx_enable_time;
+	struct iwl_sensitivity_data *data = NULL;
+	const struct iwl_sensitivity_ranges *ranges = priv->hw_params.sens;
+
+	data = &(priv->sensitivity_data);
+
+	/* If we got too many false alarms this time, reduce sensitivity */
+	if (false_alarms > max_false_alarms) {
+
+		IWL_DEBUG_CALIB("norm FA %u > max FA %u)\n",
+			     false_alarms, max_false_alarms);
+
+		val = data->auto_corr_ofdm + AUTO_CORR_STEP_OFDM;
+		data->auto_corr_ofdm =
+			min((u32)ranges->auto_corr_max_ofdm, val);
+
+		val = data->auto_corr_ofdm_mrc + AUTO_CORR_STEP_OFDM;
+		data->auto_corr_ofdm_mrc =
+			min((u32)ranges->auto_corr_max_ofdm_mrc, val);
+
+		val = data->auto_corr_ofdm_x1 + AUTO_CORR_STEP_OFDM;
+		data->auto_corr_ofdm_x1 =
+			min((u32)ranges->auto_corr_max_ofdm_x1, val);
+
+		val = data->auto_corr_ofdm_mrc_x1 + AUTO_CORR_STEP_OFDM;
+		data->auto_corr_ofdm_mrc_x1 =
+			min((u32)ranges->auto_corr_max_ofdm_mrc_x1, val);
+	}
+
+	/* Else if we got fewer than desired, increase sensitivity */
+	else if (false_alarms < min_false_alarms) {
+
+		IWL_DEBUG_CALIB("norm FA %u < min FA %u\n",
+			     false_alarms, min_false_alarms);
+
+		val = data->auto_corr_ofdm - AUTO_CORR_STEP_OFDM;
+		data->auto_corr_ofdm =
+			max((u32)ranges->auto_corr_min_ofdm, val);
+
+		val = data->auto_corr_ofdm_mrc - AUTO_CORR_STEP_OFDM;
+		data->auto_corr_ofdm_mrc =
+			max((u32)ranges->auto_corr_min_ofdm_mrc, val);
+
+		val = data->auto_corr_ofdm_x1 - AUTO_CORR_STEP_OFDM;
+		data->auto_corr_ofdm_x1 =
+			max((u32)ranges->auto_corr_min_ofdm_x1, val);
+
+		val = data->auto_corr_ofdm_mrc_x1 - AUTO_CORR_STEP_OFDM;
+		data->auto_corr_ofdm_mrc_x1 =
+			max((u32)ranges->auto_corr_min_ofdm_mrc_x1, val);
+	} else {
+		IWL_DEBUG_CALIB("min FA %u < norm FA %u < max FA %u OK\n",
+			 min_false_alarms, false_alarms, max_false_alarms);
+	}
+	return 0;
+}
+
+/* Prepare a SENSITIVITY_CMD, send to uCode if values have changed */
+static int iwl_sensitivity_write(struct iwl_priv *priv)
+{
+	int ret = 0;
+	struct iwl_sensitivity_cmd cmd ;
+	struct iwl_sensitivity_data *data = NULL;
+	struct iwl_host_cmd cmd_out = {
+		.id = SENSITIVITY_CMD,
+		.len = sizeof(struct iwl_sensitivity_cmd),
+		.meta.flags = CMD_ASYNC,
+		.data = &cmd,
+	};
+
+	data = &(priv->sensitivity_data);
+
+	memset(&cmd, 0, sizeof(cmd));
+
+	cmd.table[HD_AUTO_CORR32_X4_TH_ADD_MIN_INDEX] =
+				cpu_to_le16((u16)data->auto_corr_ofdm);
+	cmd.table[HD_AUTO_CORR32_X4_TH_ADD_MIN_MRC_INDEX] =
+				cpu_to_le16((u16)data->auto_corr_ofdm_mrc);
+	cmd.table[HD_AUTO_CORR32_X1_TH_ADD_MIN_INDEX] =
+				cpu_to_le16((u16)data->auto_corr_ofdm_x1);
+	cmd.table[HD_AUTO_CORR32_X1_TH_ADD_MIN_MRC_INDEX] =
+				cpu_to_le16((u16)data->auto_corr_ofdm_mrc_x1);
+
+	cmd.table[HD_AUTO_CORR40_X4_TH_ADD_MIN_INDEX] =
+				cpu_to_le16((u16)data->auto_corr_cck);
+	cmd.table[HD_AUTO_CORR40_X4_TH_ADD_MIN_MRC_INDEX] =
+				cpu_to_le16((u16)data->auto_corr_cck_mrc);
+
+	cmd.table[HD_MIN_ENERGY_CCK_DET_INDEX] =
+				cpu_to_le16((u16)data->nrg_th_cck);
+	cmd.table[HD_MIN_ENERGY_OFDM_DET_INDEX] =
+				cpu_to_le16((u16)data->nrg_th_ofdm);
+
+	cmd.table[HD_BARKER_CORR_TH_ADD_MIN_INDEX] =
+				__constant_cpu_to_le16(190);
+	cmd.table[HD_BARKER_CORR_TH_ADD_MIN_MRC_INDEX] =
+				__constant_cpu_to_le16(390);
+	cmd.table[HD_OFDM_ENERGY_TH_IN_INDEX] =
+				__constant_cpu_to_le16(62);
+
+	IWL_DEBUG_CALIB("ofdm: ac %u mrc %u x1 %u mrc_x1 %u thresh %u\n",
+			data->auto_corr_ofdm, data->auto_corr_ofdm_mrc,
+			data->auto_corr_ofdm_x1, data->auto_corr_ofdm_mrc_x1,
+			data->nrg_th_ofdm);
+
+	IWL_DEBUG_CALIB("cck: ac %u mrc %u thresh %u\n",
+			data->auto_corr_cck, data->auto_corr_cck_mrc,
+			data->nrg_th_cck);
+
+	/* Update uCode's "work" table, and copy it to DSP */
+	cmd.control = SENSITIVITY_CMD_CONTROL_WORK_TABLE;
+
+	/* Don't send command to uCode if nothing has changed */
+	if (!memcmp(&cmd.table[0], &(priv->sensitivity_tbl[0]),
+		    sizeof(u16)*HD_TABLE_SIZE)) {
+		IWL_DEBUG_CALIB("No change in SENSITIVITY_CMD\n");
+		return 0;
+	}
+
+	/* Copy table for comparison next time */
+	memcpy(&(priv->sensitivity_tbl[0]), &(cmd.table[0]),
+	       sizeof(u16)*HD_TABLE_SIZE);
+
+	ret = iwl_send_cmd(priv, &cmd_out);
+	if (ret)
+		IWL_ERROR("SENSITIVITY_CMD failed\n");
+
+	return ret;
+}
+
+void iwl_init_sensitivity(struct iwl_priv *priv)
+{
+	int ret = 0;
+	int i;
+	struct iwl_sensitivity_data *data = NULL;
+	const struct iwl_sensitivity_ranges *ranges = priv->hw_params.sens;
+
+	IWL_DEBUG_CALIB("Start iwl_init_sensitivity\n");
+
+	/* Clear driver's sensitivity algo data */
+	data = &(priv->sensitivity_data);
+
+	if (ranges == NULL)
+		/* can happen if IWLWIFI_RUN_TIME_CALIB is selected
+		 * but no IWLXXXX_RUN_TIME_CALIB for specific is selected */
+		return;
+
+	memset(data, 0, sizeof(struct iwl_sensitivity_data));
+
+	data->num_in_cck_no_fa = 0;
+	data->nrg_curr_state = IWL_FA_TOO_MANY;
+	data->nrg_prev_state = IWL_FA_TOO_MANY;
+	data->nrg_silence_ref = 0;
+	data->nrg_silence_idx = 0;
+	data->nrg_energy_idx = 0;
+
+	for (i = 0; i < 10; i++)
+		data->nrg_value[i] = 0;
+
+	for (i = 0; i < NRG_NUM_PREV_STAT_L; i++)
+		data->nrg_silence_rssi[i] = 0;
+
+	data->auto_corr_ofdm = 90;
+	data->auto_corr_ofdm_mrc = ranges->auto_corr_min_ofdm_mrc;
+	data->auto_corr_ofdm_x1  = ranges->auto_corr_min_ofdm_x1;
+	data->auto_corr_ofdm_mrc_x1 = ranges->auto_corr_min_ofdm_mrc_x1;
+	data->auto_corr_cck = AUTO_CORR_CCK_MIN_VAL_DEF;
+	data->auto_corr_cck_mrc = ranges->auto_corr_min_cck_mrc;
+	data->nrg_th_cck = ranges->nrg_th_cck;
+	data->nrg_th_ofdm = ranges->nrg_th_ofdm;
+
+	data->last_bad_plcp_cnt_ofdm = 0;
+	data->last_fa_cnt_ofdm = 0;
+	data->last_bad_plcp_cnt_cck = 0;
+	data->last_fa_cnt_cck = 0;
+
+	ret |= iwl_sensitivity_write(priv);
+	IWL_DEBUG_CALIB("<<return 0x%X\n", ret);
+}
+EXPORT_SYMBOL(iwl_init_sensitivity);
+
+void iwl_sensitivity_calibration(struct iwl_priv *priv,
+				    struct iwl4965_notif_statistics *resp)
+{
+	u32 rx_enable_time;
+	u32 fa_cck;
+	u32 fa_ofdm;
+	u32 bad_plcp_cck;
+	u32 bad_plcp_ofdm;
+	u32 norm_fa_ofdm;
+	u32 norm_fa_cck;
+	struct iwl_sensitivity_data *data = NULL;
+	struct statistics_rx_non_phy *rx_info = &(resp->rx.general);
+	struct statistics_rx *statistics = &(resp->rx);
+	unsigned long flags;
+	struct statistics_general_data statis;
+
+	data = &(priv->sensitivity_data);
+
+	if (!iwl_is_associated(priv)) {
+		IWL_DEBUG_CALIB("<< - not associated\n");
+		return;
+	}
+
+	spin_lock_irqsave(&priv->lock, flags);
+	if (rx_info->interference_data_flag != INTERFERENCE_DATA_AVAILABLE) {
+		IWL_DEBUG_CALIB("<< invalid data.\n");
+		spin_unlock_irqrestore(&priv->lock, flags);
+		return;
+	}
+
+	/* Extract Statistics: */
+	rx_enable_time = le32_to_cpu(rx_info->channel_load);
+	fa_cck = le32_to_cpu(statistics->cck.false_alarm_cnt);
+	fa_ofdm = le32_to_cpu(statistics->ofdm.false_alarm_cnt);
+	bad_plcp_cck = le32_to_cpu(statistics->cck.plcp_err);
+	bad_plcp_ofdm = le32_to_cpu(statistics->ofdm.plcp_err);
+
+	statis.beacon_silence_rssi_a =
+			le32_to_cpu(statistics->general.beacon_silence_rssi_a);
+	statis.beacon_silence_rssi_b =
+			le32_to_cpu(statistics->general.beacon_silence_rssi_b);
+	statis.beacon_silence_rssi_c =
+			le32_to_cpu(statistics->general.beacon_silence_rssi_c);
+	statis.beacon_energy_a =
+			le32_to_cpu(statistics->general.beacon_energy_a);
+	statis.beacon_energy_b =
+			le32_to_cpu(statistics->general.beacon_energy_b);
+	statis.beacon_energy_c =
+			le32_to_cpu(statistics->general.beacon_energy_c);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	IWL_DEBUG_CALIB("rx_enable_time = %u usecs\n", rx_enable_time);
+
+	if (!rx_enable_time) {
+		IWL_DEBUG_CALIB("<< RX Enable Time == 0! \n");
+		return;
+	}
+
+	/* These statistics increase monotonically, and do not reset
+	 *   at each beacon.  Calculate difference from last value, or just
+	 *   use the new statistics value if it has reset or wrapped around. */
+	if (data->last_bad_plcp_cnt_cck > bad_plcp_cck)
+		data->last_bad_plcp_cnt_cck = bad_plcp_cck;
+	else {
+		bad_plcp_cck -= data->last_bad_plcp_cnt_cck;
+		data->last_bad_plcp_cnt_cck += bad_plcp_cck;
+	}
+
+	if (data->last_bad_plcp_cnt_ofdm > bad_plcp_ofdm)
+		data->last_bad_plcp_cnt_ofdm = bad_plcp_ofdm;
+	else {
+		bad_plcp_ofdm -= data->last_bad_plcp_cnt_ofdm;
+		data->last_bad_plcp_cnt_ofdm += bad_plcp_ofdm;
+	}
+
+	if (data->last_fa_cnt_ofdm > fa_ofdm)
+		data->last_fa_cnt_ofdm = fa_ofdm;
+	else {
+		fa_ofdm -= data->last_fa_cnt_ofdm;
+		data->last_fa_cnt_ofdm += fa_ofdm;
+	}
+
+	if (data->last_fa_cnt_cck > fa_cck)
+		data->last_fa_cnt_cck = fa_cck;
+	else {
+		fa_cck -= data->last_fa_cnt_cck;
+		data->last_fa_cnt_cck += fa_cck;
+	}
+
+	/* Total aborted signal locks */
+	norm_fa_ofdm = fa_ofdm + bad_plcp_ofdm;
+	norm_fa_cck = fa_cck + bad_plcp_cck;
+
+	IWL_DEBUG_CALIB("cck: fa %u badp %u  ofdm: fa %u badp %u\n", fa_cck,
+			bad_plcp_cck, fa_ofdm, bad_plcp_ofdm);
+
+	iwl_sens_auto_corr_ofdm(priv, norm_fa_ofdm, rx_enable_time);
+	iwl_sens_energy_cck(priv, norm_fa_cck, rx_enable_time, &statis);
+	iwl_sensitivity_write(priv);
+
+	return;
+}
+EXPORT_SYMBOL(iwl_sensitivity_calibration);
+
+/*
+ * Accumulate 20 beacons of signal and noise statistics for each of
+ *   3 receivers/antennas/rx-chains, then figure out:
+ * 1)  Which antennas are connected.
+ * 2)  Differential rx gain settings to balance the 3 receivers.
+ */
+void iwl_chain_noise_calibration(struct iwl_priv *priv,
+			      struct iwl4965_notif_statistics *stat_resp)
+{
+	struct iwl_chain_noise_data *data = NULL;
+
+	u32 chain_noise_a;
+	u32 chain_noise_b;
+	u32 chain_noise_c;
+	u32 chain_sig_a;
+	u32 chain_sig_b;
+	u32 chain_sig_c;
+	u32 average_sig[NUM_RX_CHAINS] = {INITIALIZATION_VALUE};
+	u32 average_noise[NUM_RX_CHAINS] = {INITIALIZATION_VALUE};
+	u32 max_average_sig;
+	u16 max_average_sig_antenna_i;
+	u32 min_average_noise = MIN_AVERAGE_NOISE_MAX_VALUE;
+	u16 min_average_noise_antenna_i = INITIALIZATION_VALUE;
+	u16 i = 0;
+	u16 rxon_chnum = INITIALIZATION_VALUE;
+	u16 stat_chnum = INITIALIZATION_VALUE;
+	u8 rxon_band24;
+	u8 stat_band24;
+	u32 active_chains = 0;
+	u8 num_tx_chains;
+	unsigned long flags;
+	struct statistics_rx_non_phy *rx_info = &(stat_resp->rx.general);
+
+	data = &(priv->chain_noise_data);
+
+	/* Accumulate just the first 20 beacons after the first association,
+	 *   then we're done forever. */
+	if (data->state != IWL_CHAIN_NOISE_ACCUMULATE) {
+		if (data->state == IWL_CHAIN_NOISE_ALIVE)
+			IWL_DEBUG_CALIB("Wait for noise calib reset\n");
+		return;
+	}
+
+	spin_lock_irqsave(&priv->lock, flags);
+	if (rx_info->interference_data_flag != INTERFERENCE_DATA_AVAILABLE) {
+		IWL_DEBUG_CALIB(" << Interference data unavailable\n");
+		spin_unlock_irqrestore(&priv->lock, flags);
+		return;
+	}
+
+	rxon_band24 = !!(priv->staging_rxon.flags & RXON_FLG_BAND_24G_MSK);
+	rxon_chnum = le16_to_cpu(priv->staging_rxon.channel);
+	stat_band24 = !!(stat_resp->flag & STATISTICS_REPLY_FLG_BAND_24G_MSK);
+	stat_chnum = le32_to_cpu(stat_resp->flag) >> 16;
+
+	/* Make sure we accumulate data for just the associated channel
+	 *   (even if scanning). */
+	if ((rxon_chnum != stat_chnum) || (rxon_band24 != stat_band24)) {
+		IWL_DEBUG_CALIB("Stats not from chan=%d, band24=%d\n",
+				rxon_chnum, rxon_band24);
+		spin_unlock_irqrestore(&priv->lock, flags);
+		return;
+	}
+
+	/* Accumulate beacon statistics values across 20 beacons */
+	chain_noise_a = le32_to_cpu(rx_info->beacon_silence_rssi_a) &
+				IN_BAND_FILTER;
+	chain_noise_b = le32_to_cpu(rx_info->beacon_silence_rssi_b) &
+				IN_BAND_FILTER;
+	chain_noise_c = le32_to_cpu(rx_info->beacon_silence_rssi_c) &
+				IN_BAND_FILTER;
+
+	chain_sig_a = le32_to_cpu(rx_info->beacon_rssi_a) & IN_BAND_FILTER;
+	chain_sig_b = le32_to_cpu(rx_info->beacon_rssi_b) & IN_BAND_FILTER;
+	chain_sig_c = le32_to_cpu(rx_info->beacon_rssi_c) & IN_BAND_FILTER;
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	data->beacon_count++;
+
+	data->chain_noise_a = (chain_noise_a + data->chain_noise_a);
+	data->chain_noise_b = (chain_noise_b + data->chain_noise_b);
+	data->chain_noise_c = (chain_noise_c + data->chain_noise_c);
+
+	data->chain_signal_a = (chain_sig_a + data->chain_signal_a);
+	data->chain_signal_b = (chain_sig_b + data->chain_signal_b);
+	data->chain_signal_c = (chain_sig_c + data->chain_signal_c);
+
+	IWL_DEBUG_CALIB("chan=%d, band24=%d, beacon=%d\n",
+			rxon_chnum, rxon_band24, data->beacon_count);
+	IWL_DEBUG_CALIB("chain_sig: a %d b %d c %d\n",
+			chain_sig_a, chain_sig_b, chain_sig_c);
+	IWL_DEBUG_CALIB("chain_noise: a %d b %d c %d\n",
+			chain_noise_a, chain_noise_b, chain_noise_c);
+
+	/* If this is the 20th beacon, determine:
+	 * 1)  Disconnected antennas (using signal strengths)
+	 * 2)  Differential gain (using silence noise) to balance receivers */
+	if (data->beacon_count != CAL_NUM_OF_BEACONS)
+		return;
+
+	/* Analyze signal for disconnected antenna */
+	average_sig[0] = (data->chain_signal_a) / CAL_NUM_OF_BEACONS;
+	average_sig[1] = (data->chain_signal_b) / CAL_NUM_OF_BEACONS;
+	average_sig[2] = (data->chain_signal_c) / CAL_NUM_OF_BEACONS;
+
+	if (average_sig[0] >= average_sig[1]) {
+		max_average_sig = average_sig[0];
+		max_average_sig_antenna_i = 0;
+		active_chains = (1 << max_average_sig_antenna_i);
+	} else {
+		max_average_sig = average_sig[1];
+		max_average_sig_antenna_i = 1;
+		active_chains = (1 << max_average_sig_antenna_i);
+	}
+
+	if (average_sig[2] >= max_average_sig) {
+		max_average_sig = average_sig[2];
+		max_average_sig_antenna_i = 2;
+		active_chains = (1 << max_average_sig_antenna_i);
+	}
+
+	IWL_DEBUG_CALIB("average_sig: a %d b %d c %d\n",
+		     average_sig[0], average_sig[1], average_sig[2]);
+	IWL_DEBUG_CALIB("max_average_sig = %d, antenna %d\n",
+		     max_average_sig, max_average_sig_antenna_i);
+
+	/* Compare signal strengths for all 3 receivers. */
+	for (i = 0; i < NUM_RX_CHAINS; i++) {
+		if (i != max_average_sig_antenna_i) {
+			s32 rssi_delta = (max_average_sig - average_sig[i]);
+
+			/* If signal is very weak, compared with
+			 * strongest, mark it as disconnected. */
+			if (rssi_delta > MAXIMUM_ALLOWED_PATHLOSS)
+				data->disconn_array[i] = 1;
+			else
+				active_chains |= (1 << i);
+			IWL_DEBUG_CALIB("i = %d  rssiDelta = %d  "
+			     "disconn_array[i] = %d\n",
+			     i, rssi_delta, data->disconn_array[i]);
+		}
+	}
+
+	num_tx_chains = 0;
+	for (i = 0; i < NUM_RX_CHAINS; i++) {
+		/* loops on all the bits of
+		 * priv->hw_setting.valid_tx_ant */
+		u8 ant_msk = (1 << i);
+		if (!(priv->hw_params.valid_tx_ant & ant_msk))
+			continue;
+
+		num_tx_chains++;
+		if (data->disconn_array[i] == 0)
+			/* there is a Tx antenna connected */
+			break;
+		if (num_tx_chains == priv->hw_params.tx_chains_num &&
+		data->disconn_array[i]) {
+			/* This is the last TX antenna and is also
+			 * disconnected connect it anyway */
+			data->disconn_array[i] = 0;
+			active_chains |= ant_msk;
+			IWL_DEBUG_CALIB("All Tx chains are disconnected W/A - "
+				"declare %d as connected\n", i);
+			break;
+		}
+	}
+
+	IWL_DEBUG_CALIB("active_chains (bitwise) = 0x%x\n",
+			active_chains);
+
+	/* Save for use within RXON, TX, SCAN commands, etc. */
+	priv->valid_antenna = active_chains;
+
+	/* Analyze noise for rx balance */
+	average_noise[0] = ((data->chain_noise_a)/CAL_NUM_OF_BEACONS);
+	average_noise[1] = ((data->chain_noise_b)/CAL_NUM_OF_BEACONS);
+	average_noise[2] = ((data->chain_noise_c)/CAL_NUM_OF_BEACONS);
+
+	for (i = 0; i < NUM_RX_CHAINS; i++) {
+		if (!(data->disconn_array[i]) &&
+		   (average_noise[i] <= min_average_noise)) {
+			/* This means that chain i is active and has
+			 * lower noise values so far: */
+			min_average_noise = average_noise[i];
+			min_average_noise_antenna_i = i;
+		}
+	}
+
+	IWL_DEBUG_CALIB("average_noise: a %d b %d c %d\n",
+			average_noise[0], average_noise[1],
+			average_noise[2]);
+
+	IWL_DEBUG_CALIB("min_average_noise = %d, antenna %d\n",
+			min_average_noise, min_average_noise_antenna_i);
+
+	priv->cfg->ops->utils->gain_computation(priv, average_noise,
+		min_average_noise_antenna_i, min_average_noise);
+}
+EXPORT_SYMBOL(iwl_chain_noise_calibration);
+