mac80211: sample survey implementation for mac80211 & hwsim

This adds the survey function to both mac80211 itself and to mac80211_hwsim.
For the latter driver, we simply invent some noise level.A real driver which
cannot determine the real channel noise MUST NOT report any noise, especially
not a magically conjured one :-)
Signed-off-by: Holger Schurig <holgerschurig@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -829,6 +829,33 @@ static int mac80211_hwsim_conf_tx(
 	return 0;
 }
 
+static int mac80211_hwsim_get_survey(
+	struct ieee80211_hw *hw, int idx,
+	struct survey_info *survey)
+{
+	struct ieee80211_conf *conf = &hw->conf;
+
+	printk(KERN_DEBUG "%s:%s (idx=%d)\n",
+	       wiphy_name(hw->wiphy), __func__, idx);
+
+	if (idx != 0)
+		return -ENOENT;
+
+	/* Current channel */
+	survey->channel = conf->channel;
+
+	/*
+	 * Magically conjured noise level --- this is only ok for simulated hardware.
+	 *
+	 * A real driver which cannot determine the real channel noise MUST NOT
+	 * report any noise, especially not a magically conjured one :-)
+	 */
+	survey->filled = SURVEY_INFO_NOISE_DBM;
+	survey->noise = -92;
+
+	return 0;
+}
+
 #ifdef CONFIG_NL80211_TESTMODE
 /*
  * This section contains example code for using netlink
@@ -1012,6 +1039,7 @@ static struct ieee80211_ops mac80211_hwsim_ops =
 	.sta_notify = mac80211_hwsim_sta_notify,
 	.set_tim = mac80211_hwsim_set_tim,
 	.conf_tx = mac80211_hwsim_conf_tx,
+	.get_survey = mac80211_hwsim_get_survey,
 	CFG80211_TESTMODE_CMD(mac80211_hwsim_testmode_cmd)
 	.ampdu_action = mac80211_hwsim_ampdu_action,
 	.sw_scan_start = mac80211_hwsim_sw_scan,

include/net/mac80211.h

@@ -1674,7 +1674,8 @@ struct ieee80211_ops {
 			    struct ieee80211_vif *vif,
 			    enum ieee80211_ampdu_mlme_action action,
 			    struct ieee80211_sta *sta, u16 tid, u16 *ssn);
-
+	int (*get_survey)(struct ieee80211_hw *hw, int idx,
+		struct survey_info *survey);
 	void (*rfkill_poll)(struct ieee80211_hw *hw);
 	void (*set_coverage_class)(struct ieee80211_hw *hw, u8 coverage_class);
 #ifdef CONFIG_NL80211_TESTMODE

net/mac80211/cfg.c

@@ -410,6 +410,17 @@ static int ieee80211_dump_station(struct wiphy *wiphy, struct net_device *dev,
 	return ret;
 }
 
+static int ieee80211_dump_survey(struct wiphy *wiphy, struct net_device *dev,
+				 int idx, struct survey_info *survey)
+{
+	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+
+	if (!local->ops->get_survey)
+		return -EOPNOTSUPP;
+
+	return drv_get_survey(local, idx, survey);
+}
+
 static int ieee80211_get_station(struct wiphy *wiphy, struct net_device *dev,
 				 u8 *mac, struct station_info *sinfo)
 {
@@ -1507,6 +1518,7 @@ struct cfg80211_ops mac80211_config_ops = {
 	.change_station = ieee80211_change_station,
 	.get_station = ieee80211_get_station,
 	.dump_station = ieee80211_dump_station,
+	.dump_survey = ieee80211_dump_survey,
 #ifdef CONFIG_MAC80211_MESH
 	.add_mpath = ieee80211_add_mpath,
 	.del_mpath = ieee80211_del_mpath,

net/mac80211/driver-ops.h

@@ -346,6 +346,15 @@ static inline int drv_ampdu_action(struct ieee80211_local *local,
 	return ret;
 }
 
+static inline int drv_get_survey(struct ieee80211_local *local, int idx,
+				struct survey_info *survey)
+{
+	int ret = -EOPNOTSUPP;
+	if (local->ops->conf_tx)
+		ret = local->ops->get_survey(&local->hw, idx, survey);
+	/* trace_drv_get_survey(local, idx, survey, ret); */
+	return ret;
+}
 
 static inline void drv_rfkill_poll(struct ieee80211_local *local)
 {