mac80211: add support for driver tx power reporting

The configured tx power is often limited by hardware capabilities,
channel settings, antenna configuration, etc.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
[fix tracing compilation]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -2857,6 +2857,9 @@ enum ieee80211_roc_type {
  * @get_expected_throughput: extract the expected throughput towards the
  *	specified station. The returned value is expressed in Kbps. It returns 0
  *	if the RC algorithm does not have proper data to provide.
+ *
+ * @get_txpower: get current maximum tx power (in dBm) based on configuration
+ *	and hardware limits.
  */
 struct ieee80211_ops {
 	void (*tx)(struct ieee80211_hw *hw,
@@ -3065,6 +3068,8 @@ struct ieee80211_ops {
 	int (*join_ibss)(struct ieee80211_hw *hw, struct ieee80211_vif *vif);
 	void (*leave_ibss)(struct ieee80211_hw *hw, struct ieee80211_vif *vif);
 	u32 (*get_expected_throughput)(struct ieee80211_sta *sta);
+	int (*get_txpower)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
+			   int *dbm);
 };
 
 /**

net/mac80211/cfg.c

@@ -2133,6 +2133,9 @@ static int ieee80211_get_tx_power(struct wiphy *wiphy,
 	struct ieee80211_local *local = wiphy_priv(wiphy);
 	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
 
+	if (local->ops->get_txpower)
+		return drv_get_txpower(local, sdata, dbm);
+
 	if (!local->use_chanctx)
 		*dbm = local->hw.conf.power_level;
 	else

net/mac80211/driver-ops.h

@@ -1279,4 +1279,18 @@ static inline u32 drv_get_expected_throughput(struct ieee80211_local *local,
 	return ret;
 }
 
+static inline int drv_get_txpower(struct ieee80211_local *local,
+				  struct ieee80211_sub_if_data *sdata, int *dbm)
+{
+	int ret;
+
+	if (!local->ops->get_txpower)
+		return -EOPNOTSUPP;
+
+	ret = local->ops->get_txpower(&local->hw, &sdata->vif, dbm);
+	trace_drv_get_txpower(local, sdata, *dbm, ret);
+
+	return ret;
+}
+
 #endif /* __MAC80211_DRIVER_OPS */

net/mac80211/trace.h

@@ -2150,6 +2150,33 @@ DEFINE_EVENT(local_sdata_evt, drv_post_channel_switch,
 	     TP_ARGS(local, sdata)
 );
 
+TRACE_EVENT(drv_get_txpower,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata,
+		 int dbm, int ret),
+
+	TP_ARGS(local, sdata, dbm, ret),
+
+	TP_STRUCT__entry(
+		LOCAL_ENTRY
+		VIF_ENTRY
+		__field(int, dbm)
+		__field(int, ret)
+	),
+
+	TP_fast_assign(
+		LOCAL_ASSIGN;
+		VIF_ASSIGN;
+		__entry->dbm = dbm;
+		__entry->ret = ret;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT VIF_PR_FMT " dbm:%d ret:%d",
+		LOCAL_PR_ARG, VIF_PR_ARG, __entry->dbm, __entry->ret
+	)
+);
+
 
 #ifdef CONFIG_MAC80211_MESSAGE_TRACING
 #undef TRACE_SYSTEM