6 files changed, 145 insertions, 0 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index b29456a945c2..8ff3d8a1377c 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -194,6 +194,17 @@ enum ieee80211_bss_change {
 #define IEEE80211_BSS_ARP_ADDR_LIST_LEN 4
 
 /**
+ * enum ieee80211_rssi_event - RSSI threshold event
+ * An indicator for when RSSI goes below/above a certain threshold.
+ * @RSSI_EVENT_HIGH: AP's rssi crossed the high threshold set by the driver.
+ * @RSSI_EVENT_LOW: AP's rssi crossed the low threshold set by the driver.
+ */
+enum ieee80211_rssi_event {
+        RSSI_EVENT_HIGH,
+        RSSI_EVENT_LOW,
+};
+
+/**
  * struct ieee80211_bss_conf - holds the BSS's changing parameters
  *
  * This structure keeps information about a BSS (and an association
@@ -1867,6 +1878,8 @@ enum ieee80211_ampdu_mlme_action {
  * @set_bitrate_mask: Set a mask of rates to be used for rate control selection
  *      when transmitting a frame. Currently only legacy rates are handled.
  *      The callback can sleep.
+ * @rssi_callback: Notify driver when the average RSSI goes above/below
+ *      thresholds that were registered previously. The callback can sleep.
  */
 struct ieee80211_ops {
         void (*tx)(struct ieee80211_hw *hw, struct sk_buff *skb);
@@ -1975,6 +1988,8 @@ struct ieee80211_ops {
         bool (*tx_frames_pending)(struct ieee80211_hw *hw);
         int (*set_bitrate_mask)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                                 const struct cfg80211_bitrate_mask *mask);
+        void (*rssi_callback)(struct ieee80211_hw *hw,
+                              enum ieee80211_rssi_event rssi_event);
 };
 
 /**
@@ -3316,4 +3331,9 @@ ieee80211_vif_type_p2p(struct ieee80211_vif *vif)
         return ieee80211_iftype_p2p(vif->type, vif->p2p);
 }
 
+void ieee80211_enable_rssi_reports(struct ieee80211_vif *vif,
+                                   int rssi_min_thold,
+                                   int rssi_max_thold);
+
+void ieee80211_disable_rssi_reports(struct ieee80211_vif *vif);
 #endif /* MAC80211_H */
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index edd2dd79c9be..b2d6bba44054 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -657,4 +657,12 @@ static inline void drv_set_rekey_data(struct ieee80211_local *local,
         trace_drv_return_void(local);
 }
 
+static inline void drv_rssi_callback(struct ieee80211_local *local,
+                                     const enum ieee80211_rssi_event event)
+{
+        trace_drv_rssi_callback(local, event);
+        if (local->ops->rssi_callback)
+                local->ops->rssi_callback(&local->hw, event);
+        trace_drv_return_void(local);
+}
 #endif /* __MAC80211_DRIVER_OPS */
diff --git a/net/mac80211/driver-trace.h b/net/mac80211/driver-trace.h
index 31a9dfa81f65..4470f6e8b845 100644
--- a/net/mac80211/driver-trace.h
+++ b/net/mac80211/driver-trace.h
@@ -1052,6 +1052,28 @@ TRACE_EVENT(drv_set_rekey_data,
                   LOCAL_PR_ARG, VIF_PR_ARG)
 );
 
+TRACE_EVENT(drv_rssi_callback,
+        TP_PROTO(struct ieee80211_local *local,
+                 enum ieee80211_rssi_event rssi_event),
+
+        TP_ARGS(local, rssi_event),
+
+        TP_STRUCT__entry(
+                LOCAL_ENTRY
+                __field(u32, rssi_event)
+        ),
+
+        TP_fast_assign(
+                LOCAL_ASSIGN;
+                __entry->rssi_event = rssi_event;
+        ),
+
+        TP_printk(
+                LOCAL_PR_FMT " rssi_event:%d",
+                LOCAL_PR_ARG, __entry->rssi_event
+        )
+);
+
 /*
  * Tracing for API calls that drivers call.
  */
@@ -1342,6 +1364,30 @@ TRACE_EVENT(api_gtk_rekey_notify,
         TP_printk(VIF_PR_FMT, VIF_PR_ARG)
 );
 
+TRACE_EVENT(api_enable_rssi_reports,
+        TP_PROTO(struct ieee80211_sub_if_data *sdata,
+                 int rssi_min_thold, int rssi_max_thold),
+
+        TP_ARGS(sdata, rssi_min_thold, rssi_max_thold),
+
+        TP_STRUCT__entry(
+                VIF_ENTRY
+                __field(int, rssi_min_thold)
+                __field(int, rssi_max_thold)
+        ),
+
+        TP_fast_assign(
+                VIF_ASSIGN;
+                __entry->rssi_min_thold = rssi_min_thold;
+                __entry->rssi_max_thold = rssi_max_thold;
+        ),
+
+        TP_printk(
+                VIF_PR_FMT " rssi_min_thold =%d, rssi_max_thold = %d",
+                VIF_PR_ARG, __entry->rssi_min_thold, __entry->rssi_max_thold
+        )
+);
+
 /*
  * Tracing for internal functions
  * (which may also be called in response to driver calls)
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 4c7a831e7d1e..96600bec44c5 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -432,6 +432,14 @@ struct ieee80211_if_managed {
          * generated for the current association.
          */
         int last_cqm_event_signal;
+
+        /*
+         * State variables for keeping track of RSSI of the AP currently
+         * connected to and informing driver when RSSI has gone
+         * below/above a certain threshold.
+         */
+        int rssi_min_thold, rssi_max_thold;
+        int last_ave_beacon_signal;
 };
 
 struct ieee80211_if_ibss {
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index b6d9bd5f4d3c..4b0460ad8c8f 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1763,6 +1763,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
                 ifmgd->ave_beacon_signal = rx_status->signal * 16;
                 ifmgd->last_cqm_event_signal = 0;
                 ifmgd->count_beacon_signal = 1;
+                ifmgd->last_ave_beacon_signal = 0;
         } else {
                 ifmgd->ave_beacon_signal =
                         (IEEE80211_SIGNAL_AVE_WEIGHT * rx_status->signal * 16 +
@@ -1770,6 +1771,28 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
                          ifmgd->ave_beacon_signal) / 16;
                 ifmgd->count_beacon_signal++;
         }
+
+        if (ifmgd->rssi_min_thold != ifmgd->rssi_max_thold &&
+            ifmgd->count_beacon_signal >= IEEE80211_SIGNAL_AVE_MIN_COUNT) {
+                int sig = ifmgd->ave_beacon_signal;
+                int last_sig = ifmgd->last_ave_beacon_signal;
+
+                /*
+                 * if signal crosses either of the boundaries, invoke callback
+                 * with appropriate parameters
+                 */
+                if (sig > ifmgd->rssi_max_thold &&
+                    (last_sig <= ifmgd->rssi_min_thold || last_sig == 0)) {
+                        ifmgd->last_ave_beacon_signal = sig;
+                        drv_rssi_callback(local, RSSI_EVENT_HIGH);
+                } else if (sig < ifmgd->rssi_min_thold &&
+                           (last_sig >= ifmgd->rssi_max_thold ||
+                           last_sig == 0)) {
+                        ifmgd->last_ave_beacon_signal = sig;
+                        drv_rssi_callback(local, RSSI_EVENT_LOW);
+                }
+        }
+
         if (bss_conf->cqm_rssi_thold &&
             ifmgd->count_beacon_signal >= IEEE80211_SIGNAL_AVE_MIN_COUNT &&
             !(local->hw.flags & IEEE80211_HW_SUPPORTS_CQM_RSSI)) {
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 652e5695225a..190132063c99 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1450,3 +1450,43 @@ size_t ieee80211_ie_split_vendor(const u8 *ies, size_t ielen, size_t offset)
 
         return pos;
 }
+
+static void _ieee80211_enable_rssi_reports(struct ieee80211_sub_if_data *sdata,
+                                            int rssi_min_thold,
+                                            int rssi_max_thold)
+{
+        trace_api_enable_rssi_reports(sdata, rssi_min_thold, rssi_max_thold);
+
+        if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_STATION))
+                return;
+
+        /*
+         * Scale up threshold values before storing it, as the RSSI averaging
+         * algorithm uses a scaled up value as well. Change this scaling
+         * factor if the RSSI averaging algorithm changes.
+         */
+        sdata->u.mgd.rssi_min_thold = rssi_min_thold*16;
+        sdata->u.mgd.rssi_max_thold = rssi_max_thold*16;
+}
+
+void ieee80211_enable_rssi_reports(struct ieee80211_vif *vif,
+                                    int rssi_min_thold,
+                                    int rssi_max_thold)
+{
+        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+
+        WARN_ON(rssi_min_thold == rssi_max_thold ||
+                rssi_min_thold > rssi_max_thold);
+
+        _ieee80211_enable_rssi_reports(sdata, rssi_min_thold,
+                                       rssi_max_thold);
+}
+EXPORT_SYMBOL(ieee80211_enable_rssi_reports);
+
+void ieee80211_disable_rssi_reports(struct ieee80211_vif *vif)
+{
+        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+
+        _ieee80211_enable_rssi_reports(sdata, 0, 0);
+}
+EXPORT_SYMBOL(ieee80211_disable_rssi_reports);