iwlwifi: Add chain noise scaling factor

6x50 device requires a different scaling factor for Rx gain values sent to
device via PHY_CALIBRATION_CMD (CHAIN_NOISE_GAIN_CMD).  Rather than create
a new iwlXXXX_gain_computation() function, add new chain_noise_scale member
to struct iwl_cfg, and keep using iwl5000_gain_computation().
Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-1000.c

@@ -247,6 +247,7 @@ struct iwl_cfg iwl1000_bgn_cfg = {
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl1000_bg_cfg = {
@@ -274,6 +275,7 @@ struct iwl_cfg iwl1000_bg_cfg = {
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 MODULE_FIRMWARE(IWL1000_MODULE_FIRMWARE(IWL1000_UCODE_API_MAX));

drivers/net/wireless/iwlwifi/iwl-5000.c

@@ -179,14 +179,24 @@ static void iwl5000_gain_computation(struct iwl_priv *priv,
 			data->delta_gain_code[i] = 0;
 			continue;
 		}
-		delta_g = (1000 * ((s32)average_noise[default_chain] -
+
+		delta_g = (priv->cfg->chain_noise_scale *
+			((s32)average_noise[default_chain] -
 			(s32)average_noise[i])) / 1500;
+
 		/* bound gain by 2 bits value max, 3rd bit is sign */
 		data->delta_gain_code[i] =
 			min(abs(delta_g), (long) CHAIN_NOISE_MAX_DELTA_GAIN_CODE);
 
 		if (delta_g < 0)
-			/* set negative sign */
+			/*
+			 * set negative sign ...
+			 * note to Intel developers:  This is uCode API format,
+			 *   not the format of any internal device registers.
+			 *   Do not change this format for e.g. 6050 or similar
+			 *   devices.  Change format only if more resolution
+			 *   (i.e. more than 2 bits magnitude) is needed.
+			 */
 			data->delta_gain_code[i] |= (1 << 2);
 	}
 
@@ -1587,6 +1597,7 @@ struct iwl_cfg iwl5300_agn_cfg = {
 	.use_rts_for_ht = true, /* use rts/cts protection */
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5100_bgn_cfg = {
@@ -1612,6 +1623,7 @@ struct iwl_cfg iwl5100_bgn_cfg = {
 	.use_rts_for_ht = true, /* use rts/cts protection */
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5100_abg_cfg = {
@@ -1635,6 +1647,7 @@ struct iwl_cfg iwl5100_abg_cfg = {
 	.led_compensation = 51,
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5100_agn_cfg = {
@@ -1660,6 +1673,7 @@ struct iwl_cfg iwl5100_agn_cfg = {
 	.use_rts_for_ht = true, /* use rts/cts protection */
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5350_agn_cfg = {
@@ -1685,6 +1699,7 @@ struct iwl_cfg iwl5350_agn_cfg = {
 	.use_rts_for_ht = true, /* use rts/cts protection */
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5150_agn_cfg = {
@@ -1710,6 +1725,7 @@ struct iwl_cfg iwl5150_agn_cfg = {
 	.use_rts_for_ht = true, /* use rts/cts protection */
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5150_abg_cfg = {
@@ -1733,6 +1749,7 @@ struct iwl_cfg iwl5150_abg_cfg = {
 	.led_compensation = 51,
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 MODULE_FIRMWARE(IWL5000_MODULE_FIRMWARE(IWL5000_UCODE_API_MAX));

drivers/net/wireless/iwlwifi/iwl-6000.c

@@ -324,6 +324,7 @@ struct iwl_cfg iwl6000i_2agn_cfg = {
 	.adv_thermal_throttle = true,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl6000i_2abg_cfg = {
@@ -354,6 +355,7 @@ struct iwl_cfg iwl6000i_2abg_cfg = {
 	.adv_thermal_throttle = true,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl6000i_2bg_cfg = {
@@ -384,6 +386,7 @@ struct iwl_cfg iwl6000i_2bg_cfg = {
 	.adv_thermal_throttle = true,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl6050_2agn_cfg = {
@@ -415,6 +418,7 @@ struct iwl_cfg iwl6050_2agn_cfg = {
 	.adv_thermal_throttle = true,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1500,
 };
 
 struct iwl_cfg iwl6050_2abg_cfg = {
@@ -445,6 +449,7 @@ struct iwl_cfg iwl6050_2abg_cfg = {
 	.adv_thermal_throttle = true,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1500,
 };
 
 struct iwl_cfg iwl6000_3agn_cfg = {
@@ -476,6 +481,7 @@ struct iwl_cfg iwl6000_3agn_cfg = {
 	.adv_thermal_throttle = true,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 MODULE_FIRMWARE(IWL6000_MODULE_FIRMWARE(IWL6000_UCODE_API_MAX));

drivers/net/wireless/iwlwifi/iwl-core.h

@@ -293,6 +293,7 @@ struct iwl_cfg {
 	bool support_ct_kill_exit;
 	const bool support_wimax_coexist;
 	u8 plcp_delta_threshold;
+	s32 chain_noise_scale;
 };
 
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