iwlwifi: mvm: Fix skip over dtim configuration in d0i3

There was some confusion concerning the units of the beacon interval.
The driver assumed that it was in msec where it was in TU - so fix that.
Skip over dtim was capped by 300TU where it should be by 306TU.
It should also be subjected to several conditions:
Not a DFS channel, dtim period < 10, and the multicast wake-lock
is off.  Concerning multicast lock - there is an implementation gap
in the supplicant, so just leave a TODO.
Signed-off-by: Avri Altman <avri.altman@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

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

@@ -286,12 +286,28 @@ static bool iwl_mvm_power_allow_uapsd(struct iwl_mvm *mvm,
 	return true;
 }
 
+static bool iwl_mvm_power_is_radar(struct ieee80211_vif *vif)
+{
+	struct ieee80211_chanctx_conf *chanctx_conf;
+	struct ieee80211_channel *chan;
+	bool radar_detect = false;
+
+	rcu_read_lock();
+	chanctx_conf = rcu_dereference(vif->chanctx_conf);
+	WARN_ON(!chanctx_conf);
+	if (chanctx_conf) {
+		chan = chanctx_conf->def.chan;
+		radar_detect = chan->flags & IEEE80211_CHAN_RADAR;
+	}
+	rcu_read_unlock();
+
+	return radar_detect;
+}
+
 static void iwl_mvm_power_build_cmd(struct iwl_mvm *mvm,
 				    struct ieee80211_vif *vif,
 				    struct iwl_mac_power_cmd *cmd)
 {
-	struct ieee80211_chanctx_conf *chanctx_conf;
-	struct ieee80211_channel *chan;
 	int dtimper, dtimper_msec;
 	int keep_alive;
 	bool radar_detect = false;
@@ -333,14 +349,7 @@ static void iwl_mvm_power_build_cmd(struct iwl_mvm *mvm,
 	}
 
 	/* Check if radar detection is required on current channel */
-	rcu_read_lock();
-	chanctx_conf = rcu_dereference(vif->chanctx_conf);
-	WARN_ON(!chanctx_conf);
-	if (chanctx_conf) {
-		chan = chanctx_conf->def.chan;
-		radar_detect = chan->flags & IEEE80211_CHAN_RADAR;
-	}
-	rcu_read_unlock();
+	radar_detect = iwl_mvm_power_is_radar(vif);
 
 	/* Check skip over DTIM conditions */
 	if (!radar_detect && (dtimper <= 10) &&
@@ -961,17 +970,22 @@ int iwl_mvm_update_d0i3_power_mode(struct iwl_mvm *mvm,
 
 	iwl_mvm_power_build_cmd(mvm, vif, &cmd);
 	if (enable) {
-		/* configure skip over dtim up to 300 msec */
+		/* configure skip over dtim up to 306TU - 314 msec */
 		int dtimper = vif->bss_conf.dtim_period ?: 1;
-		int dtimper_msec = dtimper * vif->bss_conf.beacon_int;
+		int dtimper_tu = dtimper * vif->bss_conf.beacon_int;
+		bool radar_detect = iwl_mvm_power_is_radar(vif);
 
-		if (WARN_ON(!dtimper_msec))
+		if (WARN_ON(!dtimper_tu))
 			return 0;
 
-		cmd.skip_dtim_periods = 300 / dtimper_msec;
-		if (cmd.skip_dtim_periods)
-			cmd.flags |=
-				cpu_to_le16(POWER_FLAGS_SKIP_OVER_DTIM_MSK);
+		/* Check skip over DTIM conditions */
+		/* TODO: check that multicast wake lock is off */
+		if (!radar_detect && (dtimper < 10)) {
+			cmd.skip_dtim_periods = 306 / dtimper_tu;
+			if (cmd.skip_dtim_periods)
+				cmd.flags |= cpu_to_le16(
+					POWER_FLAGS_SKIP_OVER_DTIM_MSK);
+		}
 	}
 	iwl_mvm_power_log(mvm, &cmd);
 #ifdef CONFIG_IWLWIFI_DEBUGFS