iwlwifi: mvm: implement reduced Tx power

This allows to have better wifi TPT when BT is active under
good RSSI conditions.
Wifi will have better chance to send Acks and Cts even if BT
is active.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/mvm/bt-coex.c

@@ -61,6 +61,8 @@
  *
  *****************************************************************************/
 
+#include <net/mac80211.h>
+
 #include "fw-api-bt-coex.h"
 #include "iwl-modparams.h"
 #include "mvm.h"
@@ -96,6 +98,20 @@ static const u8 iwl_bt_prio_tbl[BT_COEX_PRIO_TBL_EVT_MAX] = {
 
 #undef EVENT_PRIO_ANT
 
+/* BT Antenna Coupling Threshold (dB) */
+#define IWL_BT_ANTENNA_COUPLING_THRESHOLD	(35)
+#define IWL_BT_LOAD_FORCE_SISO_THRESHOLD	(3)
+
+#define BT_ENABLE_REDUCED_TXPOWER_THRESHOLD	(-62)
+#define BT_DISABLE_REDUCED_TXPOWER_THRESHOLD	(-65)
+#define BT_REDUCED_TX_POWER_BIT			BIT(7)
+
+static inline bool is_loose_coex(void)
+{
+	return iwlwifi_mod_params.ant_coupling >
+		IWL_BT_ANTENNA_COUPLING_THRESHOLD;
+}
+
 int iwl_send_bt_prio_tbl(struct iwl_mvm *mvm)
 {
 	return iwl_mvm_send_cmd_pdu(mvm, BT_COEX_PRIO_TABLE, CMD_SYNC,
@@ -186,11 +202,6 @@ static const __le32 iwl_concurrent_lookup[BT_COEX_LUT_SIZE] = {
 	cpu_to_le32(0x00000000),
 };
 
-/* BT Antenna Coupling Threshold (dB) */
-#define IWL_BT_ANTENNA_COUPLING_THRESHOLD	(35)
-#define IWL_BT_LOAD_FORCE_SISO_THRESHOLD	(3)
-
-
 int iwl_send_bt_init_conf(struct iwl_mvm *mvm)
 {
 	struct iwl_bt_coex_cmd cmd = {
@@ -214,7 +225,7 @@ int iwl_send_bt_init_conf(struct iwl_mvm *mvm)
 					BT_VALID_REDUCED_TX_POWER |
 					BT_VALID_LUT);
 
-	if (iwlwifi_mod_params.ant_coupling > IWL_BT_ANTENNA_COUPLING_THRESHOLD)
+	if (is_loose_coex())
 		memcpy(&cmd.decision_lut, iwl_loose_lookup,
 		       sizeof(iwl_tight_lookup));
 	else
@@ -227,6 +238,8 @@ int iwl_send_bt_init_conf(struct iwl_mvm *mvm)
 	cmd.kill_cts_msk =
 		cpu_to_le32(iwl_bt_cts_kill_msk[BT_KILL_MSK_DEFAULT]);
 
+	memset(&mvm->last_bt_notif, 0, sizeof(mvm->last_bt_notif));
+
 	/* go to CALIB state in internal BT-Coex state machine */
 	ret = iwl_send_bt_env(mvm, BT_COEX_ENV_OPEN,
 			      BT_COEX_PRIO_TBL_EVT_INIT_CALIB2);
@@ -242,19 +255,101 @@ int iwl_send_bt_init_conf(struct iwl_mvm *mvm)
 				    sizeof(cmd), &cmd);
 }
 
-struct iwl_bt_notif_iterator_data {
-	struct iwl_mvm *mvm;
+static int iwl_mvm_bt_udpate_ctrl_kill_msk(struct iwl_mvm *mvm,
+					   bool reduced_tx_power)
+{
+	enum iwl_bt_kill_msk bt_kill_msk;
+	struct iwl_bt_coex_cmd cmd = {};
+	struct iwl_bt_coex_profile_notif *notif = &mvm->last_bt_notif;
+
+	lockdep_assert_held(&mvm->mutex);
+
+	if (reduced_tx_power) {
+		/* Reduced Tx power has precedence on the type of the profile */
+		bt_kill_msk = BT_KILL_MSK_REDUCED_TXPOW;
+	} else {
+		/* Low latency BT profile is active: give higher prio to BT */
+		if (BT_MBOX_MSG(notif, 3, SCO_STATE)  ||
+		    BT_MBOX_MSG(notif, 3, A2DP_STATE) ||
+		    BT_MBOX_MSG(notif, 3, SNIFF_STATE))
+			bt_kill_msk = BT_KILL_MSK_SCO_HID_A2DP;
+		else
+			bt_kill_msk = BT_KILL_MSK_DEFAULT;
+	}
+
+	IWL_DEBUG_COEX(mvm,
+		       "Update kill_msk: %d - SCO %sactive A2DP %sactive SNIFF %sactive\n",
+		       bt_kill_msk,
+		       BT_MBOX_MSG(notif, 3, SCO_STATE) ? "" : "in",
+		       BT_MBOX_MSG(notif, 3, A2DP_STATE) ? "" : "in",
+		       BT_MBOX_MSG(notif, 3, SNIFF_STATE) ? "" : "in");
+
+	/* Don't send HCMD if there is no update */
+	if (bt_kill_msk == mvm->bt_kill_msk)
+		return 0;
+
+	mvm->bt_kill_msk = bt_kill_msk;
+	cmd.kill_ack_msk = cpu_to_le32(iwl_bt_ack_kill_msk[bt_kill_msk]);
+	cmd.kill_cts_msk = cpu_to_le32(iwl_bt_cts_kill_msk[bt_kill_msk]);
+	cmd.valid_bit_msk = cpu_to_le16(BT_VALID_KILL_ACK | BT_VALID_KILL_CTS);
+
+	IWL_DEBUG_COEX(mvm, "bt_kill_msk = %d\n", bt_kill_msk);
+	return iwl_mvm_send_cmd_pdu(mvm, BT_CONFIG, CMD_SYNC,
+				    sizeof(cmd), &cmd);
+}
+
+static int iwl_mvm_bt_coex_reduced_txp(struct iwl_mvm *mvm, u8 sta_id,
+				       bool enable)
+{
+	struct iwl_bt_coex_cmd cmd = {
+		.valid_bit_msk = cpu_to_le16(BT_VALID_REDUCED_TX_POWER),
+		.bt_reduced_tx_power = sta_id,
+	};
+	struct ieee80211_sta *sta;
+	struct iwl_mvm_sta *mvmsta;
+
+	/* This can happen if the station has been removed right now */
+	if (sta_id == IWL_MVM_STATION_COUNT)
+		return 0;
+
+	sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[sta_id],
+					lockdep_is_held(&mvm->mutex));
+	mvmsta = (void *)sta->drv_priv;
+
+	/* nothing to do */
+	if (mvmsta->bt_reduced_txpower == enable)
+		return 0;
+
+	if (enable)
+		cmd.bt_reduced_tx_power |= BT_REDUCED_TX_POWER_BIT;
+
+	IWL_DEBUG_COEX(mvm, "%sable reduced Tx Power for sta %d\n",
+		       enable ? "en" : "dis", sta_id);
+
+	mvmsta->bt_reduced_txpower = enable;
+
+	/* Send ASYNC since this can be sent from an atomic context */
+	return iwl_mvm_send_cmd_pdu(mvm, BT_CONFIG, CMD_ASYNC,
+				    sizeof(cmd), &cmd);
+}
+
+struct iwl_bt_iterator_data {
 	struct iwl_bt_coex_profile_notif *notif;
+	enum iwl_bt_kill_msk bt_kill_msk;
+	struct iwl_mvm *mvm;
+	u32 num_bss_ifaces;
 };
 
 static void iwl_mvm_bt_notif_iterator(void *_data, u8 *mac,
 				      struct ieee80211_vif *vif)
 {
 	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
-	struct iwl_bt_notif_iterator_data *data = _data;
+	struct iwl_bt_iterator_data *data = _data;
+	struct iwl_mvm *mvm = data->mvm;
 	struct ieee80211_chanctx_conf *chanctx_conf;
 	enum ieee80211_smps_mode smps_mode;
 	enum ieee80211_band band;
+	int ave_rssi;
 
 	if (vif->type != NL80211_IFTYPE_STATION)
 		return;
@@ -284,20 +379,72 @@ static void iwl_mvm_bt_notif_iterator(void *_data, u8 *mac,
 		       data->notif->bt_traffic_load, smps_mode);
 
 	ieee80211_request_smps(vif, smps_mode);
+
+	/* don't reduce the Tx power if in loose scheme */
+	if (is_loose_coex())
+		return;
+
+	data->num_bss_ifaces++;
+
+	/* reduced Txpower only if there are open BT connections, so ...*/
+	if (!BT_MBOX_MSG(data->notif, 3, OPEN_CON_2)) {
+		/* ... cancel reduced Tx power ... */
+		if (iwl_mvm_bt_coex_reduced_txp(mvm, mvmvif->ap_sta_id, false))
+			IWL_ERR(mvm, "Couldn't send BT_CONFIG cmd\n");
+
+		/* ... use default values for bt_kill_msk ... */
+		data->bt_kill_msk = BT_KILL_MSK_DEFAULT;
+
+		/* ... and there is no need to get reports on RSSI any more. */
+		ieee80211_disable_rssi_reports(vif);
+		return;
+	}
+
+	ave_rssi = ieee80211_ave_rssi(vif);
+
+	/* if the RSSI isn't valid, fake it is very low */
+	if (!ave_rssi)
+		ave_rssi = -100;
+	if (ave_rssi > BT_ENABLE_REDUCED_TXPOWER_THRESHOLD) {
+		if (iwl_mvm_bt_coex_reduced_txp(mvm, mvmvif->ap_sta_id, true))
+			IWL_ERR(mvm, "Couldn't send BT_CONFIG cmd\n");
+
+		/*
+		 * bt_kill_msk can be BT_KILL_MSK_REDUCED_TXPOW only if all the
+		 * BSS / P2P clients have rssi above threshold.
+		 * We set the bt_kill_msk to BT_KILL_MSK_REDUCED_TXPOW before
+		 * the iteration, if one interface's rssi isn't good enough,
+		 * bt_kill_msk will be set to default values.
+		 */
+	} else if (ave_rssi < BT_DISABLE_REDUCED_TXPOWER_THRESHOLD) {
+		if (iwl_mvm_bt_coex_reduced_txp(mvm, mvmvif->ap_sta_id, false))
+			IWL_ERR(mvm, "Couldn't send BT_CONFIG cmd\n");
+
+		/*
+		 * One interface hasn't rssi above threshold, bt_kill_msk must
+		 * be set to default values.
+		 */
+		data->bt_kill_msk = BT_KILL_MSK_DEFAULT;
+	}
+
+	/* Begin to monitor the RSSI: it may influence the reduced Tx power */
+	ieee80211_enable_rssi_reports(vif, BT_DISABLE_REDUCED_TXPOWER_THRESHOLD,
+				      BT_ENABLE_REDUCED_TXPOWER_THRESHOLD);
 }
 
+/* upon association, the fw will send in BT Coex notification */
 int iwl_mvm_rx_bt_coex_notif(struct iwl_mvm *mvm,
 			     struct iwl_rx_cmd_buffer *rxb,
 			     struct iwl_device_cmd *dev_cmd)
 {
 	struct iwl_rx_packet *pkt = rxb_addr(rxb);
 	struct iwl_bt_coex_profile_notif *notif = (void *)pkt->data;
-	struct iwl_bt_notif_iterator_data data = {
+	struct iwl_bt_iterator_data data = {
 		.mvm = mvm,
 		.notif = notif,
+		.bt_kill_msk = BT_KILL_MSK_REDUCED_TXPOW,
 	};
-	struct iwl_bt_coex_cmd cmd = {};
-	enum iwl_bt_kill_msk bt_kill_msk;
+	bool reduced_tx_power;
 
 	IWL_DEBUG_COEX(mvm, "BT Coex Notification received\n");
 	IWL_DEBUG_COEX(mvm, "\tBT %salive\n", notif->bt_status ? "" : "not ");
@@ -314,34 +461,109 @@ int iwl_mvm_rx_bt_coex_notif(struct iwl_mvm *mvm,
 					mvm->hw, IEEE80211_IFACE_ITER_NORMAL,
 					iwl_mvm_bt_notif_iterator, &data);
 
-	/* Low latency BT profile is active: give higher prio to BT */
-	if (BT_MBOX_MSG(notif, 3, SCO_STATE)  ||
-	    BT_MBOX_MSG(notif, 3, A2DP_STATE) ||
-	    BT_MBOX_MSG(notif, 3, SNIFF_STATE))
-		bt_kill_msk = BT_KILL_MSK_SCO_HID_A2DP;
+	/*
+	 * If there are no BSS / P2P client interfaces, reduced Tx Power is
+	 * irrelevant since it is based on the RSSI coming from the beacon.
+	 * Use BT_KILL_MSK_DEFAULT in that case.
+	 */
+	if (!data.num_bss_ifaces)
+		data.bt_kill_msk = BT_KILL_MSK_DEFAULT;
+
+	reduced_tx_power = data.num_bss_ifaces &&
+			   data.bt_kill_msk == BT_KILL_MSK_REDUCED_TXPOW;
+
+	if (iwl_mvm_bt_udpate_ctrl_kill_msk(mvm, reduced_tx_power))
+		IWL_ERR(mvm, "Failed to update the ctrl_kill_msk\n");
+
+	/*
+	 * This is an async handler for a notification, returning anything other
+	 * than 0 doesn't make sense even if HCMD failed.
+	 */
+	return 0;
+}
+
+static void iwl_mvm_bt_rssi_iterator(void *_data, u8 *mac,
+				   struct ieee80211_vif *vif)
+{
+	struct iwl_mvm_vif *mvmvif = (void *)vif->drv_priv;
+	struct iwl_bt_iterator_data *data = _data;
+	struct iwl_mvm *mvm = data->mvm;
+
+	struct ieee80211_sta *sta;
+	struct iwl_mvm_sta *mvmsta;
+
+	if (vif->type != NL80211_IFTYPE_STATION ||
+	    mvmvif->ap_sta_id == IWL_MVM_STATION_COUNT)
+		return;
+
+	sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[mvmvif->ap_sta_id],
+					lockdep_is_held(&mvm->mutex));
+	mvmsta = (void *)sta->drv_priv;
+
+	/*
+	 * This interface doesn't support reduced Tx power (because of low
+	 * RSSI probably), then set bt_kill_msk to default values.
+	 */
+	if (!mvmsta->bt_reduced_txpower)
+		data->bt_kill_msk = BT_KILL_MSK_DEFAULT;
+	/* else - possibly leave it to BT_KILL_MSK_REDUCED_TXPOW */
+}
+
+void iwl_mvm_bt_rssi_event(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
+			   enum ieee80211_rssi_event rssi_event)
+{
+	struct iwl_mvm_vif *mvmvif = (void *)vif->drv_priv;
+	bool reduced_tx_power;
+	struct iwl_bt_iterator_data data = {
+		.mvm = mvm,
+		.bt_kill_msk = BT_KILL_MSK_REDUCED_TXPOW,
+	};
+	int ret;
+
+	mutex_lock(&mvm->mutex);
+
+	/* Rssi update while not associated ?! */
+	if (WARN_ON_ONCE(mvmvif->ap_sta_id == IWL_MVM_STATION_COUNT))
+		goto out_unlock;
+
+	/* No open connection - reports should be disabled */
+	if (!BT_MBOX_MSG(&mvm->last_bt_notif, 3, OPEN_CON_2))
+		goto out_unlock;
+
+	IWL_DEBUG_COEX(mvm, "RSSI for %pM is now %s\n", vif->bss_conf.bssid,
+		       rssi_event == RSSI_EVENT_HIGH ? "HIGH" : "LOW");
+
+	/*
+	 * Check if rssi is good enough for reduced Tx power, but not in loose
+	 * scheme.
+	 */
+	if (rssi_event == RSSI_EVENT_LOW || is_loose_coex())
+		ret = iwl_mvm_bt_coex_reduced_txp(mvm, mvmvif->ap_sta_id,
+						  false);
 	else
-		bt_kill_msk = BT_KILL_MSK_DEFAULT;
+		ret = iwl_mvm_bt_coex_reduced_txp(mvm, mvmvif->ap_sta_id, true);
 
-	/* Don't send HCMD if there is no update */
-	if (bt_kill_msk == mvm->bt_kill_msk)
-		return 0;
+	if (ret)
+		IWL_ERR(mvm, "couldn't send BT_CONFIG HCMD upon RSSI event\n");
 
-	IWL_DEBUG_COEX(mvm,
-		       "Update kill_msk: %d - SCO %sactive A2DP %sactive SNIFF %sactive\n",
-		       bt_kill_msk,
-		       BT_MBOX_MSG(notif, 3, SCO_STATE) ? "" : "in",
-		       BT_MBOX_MSG(notif, 3, A2DP_STATE) ? "" : "in",
-		       BT_MBOX_MSG(notif, 3, SNIFF_STATE) ? "" : "in");
+	ieee80211_iterate_active_interfaces_atomic(
+		mvm->hw, IEEE80211_IFACE_ITER_NORMAL,
+		iwl_mvm_bt_rssi_iterator, &data);
 
-	mvm->bt_kill_msk = bt_kill_msk;
-	cmd.kill_ack_msk = cpu_to_le32(iwl_bt_ack_kill_msk[bt_kill_msk]);
-	cmd.kill_cts_msk = cpu_to_le32(iwl_bt_cts_kill_msk[bt_kill_msk]);
+	/*
+	 * If there are no BSS / P2P client interfaces, reduced Tx Power is
+	 * irrelevant since it is based on the RSSI coming from the beacon.
+	 * Use BT_KILL_MSK_DEFAULT in that case.
+	 */
+	if (!data.num_bss_ifaces)
+		data.bt_kill_msk = BT_KILL_MSK_DEFAULT;
 
-	cmd.valid_bit_msk = cpu_to_le16(BT_VALID_KILL_ACK | BT_VALID_KILL_CTS);
+	reduced_tx_power = data.num_bss_ifaces &&
+			   data.bt_kill_msk == BT_KILL_MSK_REDUCED_TXPOW;
 
-	if (iwl_mvm_send_cmd_pdu(mvm, BT_CONFIG, CMD_SYNC, sizeof(cmd), &cmd))
-		IWL_ERR(mvm, "Failed to sent BT Coex CMD\n");
+	if (iwl_mvm_bt_udpate_ctrl_kill_msk(mvm, reduced_tx_power))
+		IWL_ERR(mvm, "Failed to update the ctrl_kill_msk\n");
 
-	/* This handler is ASYNC */
-	return 0;
+ out_unlock:
+	mutex_unlock(&mvm->mutex);
 }

drivers/net/wireless/iwlwifi/mvm/debugfs.c

@@ -333,9 +333,18 @@ static ssize_t iwl_dbgfs_mac_params_read(struct file *file,
 				 mvmvif->queue_params[i].uapsd);
 	}
 
-	if (vif->type == NL80211_IFTYPE_STATION)
-		pos += scnprintf(buf+pos, bufsz-pos, "ap_sta_id %d\n",
-				 ap_sta_id);
+	if (vif->type == NL80211_IFTYPE_STATION &&
+	    ap_sta_id != IWL_MVM_STATION_COUNT) {
+		struct ieee80211_sta *sta;
+		struct iwl_mvm_sta *mvm_sta;
+
+		sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[ap_sta_id],
+						lockdep_is_held(&mvm->mutex));
+		mvm_sta = (void *)sta->drv_priv;
+		pos += scnprintf(buf+pos, bufsz-pos,
+				 "ap_sta_id %d - reduced Tx power %d\n",
+				 ap_sta_id, mvm_sta->bt_reduced_txpower);
+	}
 
 	rcu_read_lock();
 	chanctx_conf = rcu_dereference(vif->chanctx_conf);

drivers/net/wireless/iwlwifi/mvm/mac80211.c

@@ -1329,6 +1329,15 @@ static int iwl_mvm_set_tim(struct ieee80211_hw *hw,
 	return iwl_mvm_mac_ctxt_beacon_changed(mvm, mvm_sta->vif);
 }
 
+static void iwl_mvm_mac_rssi_callback(struct ieee80211_hw *hw,
+				      struct ieee80211_vif *vif,
+				      enum ieee80211_rssi_event rssi_event)
+{
+	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
+
+	iwl_mvm_bt_rssi_event(mvm, vif, rssi_event);
+}
+
 struct ieee80211_ops iwl_mvm_hw_ops = {
 	.tx = iwl_mvm_mac_tx,
 	.ampdu_action = iwl_mvm_mac_ampdu_action,
@@ -1352,6 +1361,7 @@ struct ieee80211_ops iwl_mvm_hw_ops = {
 	.update_tkip_key = iwl_mvm_mac_update_tkip_key,
 	.remain_on_channel = iwl_mvm_roc,
 	.cancel_remain_on_channel = iwl_mvm_cancel_roc,
+	.rssi_callback = iwl_mvm_mac_rssi_callback,
 
 	.add_chanctx = iwl_mvm_add_chanctx,
 	.remove_chanctx = iwl_mvm_remove_chanctx,

drivers/net/wireless/iwlwifi/mvm/mvm.h

@@ -522,5 +522,7 @@ int iwl_send_bt_init_conf(struct iwl_mvm *mvm);
 int iwl_mvm_rx_bt_coex_notif(struct iwl_mvm *mvm,
 			     struct iwl_rx_cmd_buffer *rxb,
 			     struct iwl_device_cmd *cmd);
+void iwl_mvm_bt_rssi_event(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
+			   enum ieee80211_rssi_event rssi_event);
 
 #endif /* __IWL_MVM_H__ */

drivers/net/wireless/iwlwifi/mvm/sta.h

@@ -271,6 +271,7 @@ struct iwl_mvm_tid_data {
  * @tid_disable_agg: bitmap: if bit(tid) is set, the fw won't send ampdus for
  *	tid.
  * @max_agg_bufsize: the maximal size of the AGG buffer for this station
+ * @bt_reduced_txpower: is reduced tx power enabled for this station
  * @lock: lock to protect the whole struct. Since %tid_data is access from Tx
  * and from Tx response flow, it needs a spinlock.
  * @pending_frames: number of frames for this STA on the shared Tx queues.
@@ -287,6 +288,7 @@ struct iwl_mvm_sta {
 	u32 mac_id_n_color;
 	u16 tid_disable_agg;
 	u8 max_agg_bufsize;
+	bool bt_reduced_txpower;
 	spinlock_t lock;
 	atomic_t pending_frames;
 	struct iwl_mvm_tid_data tid_data[IWL_MAX_TID_COUNT];