iwlwifi: mvm: add CSA absent time event for clients

Add an absent time event when pre_channel_switch is called and use the
time event started indication to set the disable_tx bit instead of
doing it in unassign_vif().  This is done so that the firmware queues
are stopped before the actual switch takes place to avoid losing
packets while the AP/GO is performing its actual switch.

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>

5 files changed, 81 insertions, 18 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
index fdeaab3457a3..ac1cef6a6b03 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -2891,7 +2891,6 @@ static void __iwl_mvm_unassign_vif_chanctx(struct iwl_mvm *mvm,
 {
         struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
         struct ieee80211_vif *disabled_vif = NULL;
-        struct iwl_mvm_sta *mvmsta;
 
         lockdep_assert_held(&mvm->mutex);
 
@@ -2925,12 +2924,6 @@ static void __iwl_mvm_unassign_vif_chanctx(struct iwl_mvm *mvm,
 
                 disabled_vif = vif;
 
-                mvmsta = iwl_mvm_sta_from_staid_protected(mvm,
-                                                          mvmvif->ap_sta_id);
-
-                if (!WARN_ON(!mvmsta))
-                        iwl_mvm_sta_modify_disable_tx(mvm, mvmsta, true);
-
                 iwl_mvm_mac_ctxt_changed(mvm, vif, true, NULL);
                 break;
         default:
@@ -3167,6 +3160,7 @@ static int iwl_mvm_pre_channel_switch(struct ieee80211_hw *hw,
         struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
         struct ieee80211_vif *csa_vif;
         struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+        u32 apply_time;
         int ret;
 
         mutex_lock(&mvm->mutex);
@@ -3194,6 +3188,17 @@ static int iwl_mvm_pre_channel_switch(struct ieee80211_hw *hw,
                 }
 
                 break;
+        case NL80211_IFTYPE_STATION:
+                apply_time = chsw->timestamp +
+                        (vif->bss_conf.beacon_int * chsw->count * 1024);
+
+                if (chsw->block_tx)
+                        iwl_mvm_csa_client_absent(mvm, vif);
+
+                iwl_mvm_schedule_csa_period(mvm, vif,
+                                            IWL_MVM_CHANNEL_SWITCH_TIME_CLIENT,
+                                            apply_time);
+                break;
         default:
                 break;
         }
diff --git a/drivers/net/wireless/iwlwifi/mvm/mvm.h b/drivers/net/wireless/iwlwifi/mvm/mvm.h
index 2c54c522b8c6..2816c6b9222b 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/iwlwifi/mvm/mvm.h
@@ -87,11 +87,12 @@
 /* A TimeUnit is 1024 microsecond */
 #define MSEC_TO_TU(_msec)       (_msec*1000/1024)
 
-/* This value represents the number of TUs before CSA "beacon 0" TBTT
- * when the CSA time-event needs to be scheduled to start.  It must be
- * big enough to ensure that we switch in time.
+/* These values represent the number of TUs before CSA "beacon 0" TBTT
+ * when the CSA time-event needs to be scheduled to start.  They must
+ * be big enough to ensure that we switch in time.
  */
 #define IWL_MVM_CHANNEL_SWITCH_TIME_GO          40
+#define IWL_MVM_CHANNEL_SWITCH_TIME_CLIENT      110
 
 /*
  * This value (in TUs) is used to fine tune the CSA NoA end time which should
@@ -797,6 +798,26 @@ static inline bool iwl_mvm_is_radio_killed(struct iwl_mvm *mvm)
                test_bit(IWL_MVM_STATUS_HW_CTKILL, &mvm->status);
 }
 
+/* Must be called with rcu_read_lock() held and it can only be
+ * released when mvmsta is not needed anymore.
+ */
+static inline struct iwl_mvm_sta *
+iwl_mvm_sta_from_staid_rcu(struct iwl_mvm *mvm, u8 sta_id)
+{
+        struct ieee80211_sta *sta;
+
+        if (sta_id >= ARRAY_SIZE(mvm->fw_id_to_mac_id))
+                return NULL;
+
+        sta = rcu_dereference(mvm->fw_id_to_mac_id[sta_id]);
+
+        /* This can happen if the station has been removed right now */
+        if (IS_ERR_OR_NULL(sta))
+                return NULL;
+
+        return iwl_mvm_sta_from_mac80211(sta);
+}
+
 static inline struct iwl_mvm_sta *
 iwl_mvm_sta_from_staid_protected(struct iwl_mvm *mvm, u8 sta_id)
 {
diff --git a/drivers/net/wireless/iwlwifi/mvm/sta.c b/drivers/net/wireless/iwlwifi/mvm/sta.c
index a38f1f151ff5..d86fe432e51f 100644
--- a/drivers/net/wireless/iwlwifi/mvm/sta.c
+++ b/drivers/net/wireless/iwlwifi/mvm/sta.c
@@ -1732,3 +1732,18 @@ void iwl_mvm_modify_all_sta_disable_tx(struct iwl_mvm *mvm,
                 iwl_mvm_sta_modify_disable_tx_ap(mvm, sta, disable);
         }
 }
+
+void iwl_mvm_csa_client_absent(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
+{
+        struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+        struct iwl_mvm_sta *mvmsta;
+
+        rcu_read_lock();
+
+        mvmsta = iwl_mvm_sta_from_staid_rcu(mvm, mvmvif->ap_sta_id);
+
+        if (!WARN_ON(!mvmsta))
+                iwl_mvm_sta_modify_disable_tx(mvm, mvmsta, true);
+
+        rcu_read_unlock();
+}
diff --git a/drivers/net/wireless/iwlwifi/mvm/sta.h b/drivers/net/wireless/iwlwifi/mvm/sta.h
index 2c869bcb9490..d8f48975ad08 100644
--- a/drivers/net/wireless/iwlwifi/mvm/sta.h
+++ b/drivers/net/wireless/iwlwifi/mvm/sta.h
@@ -422,5 +422,6 @@ void iwl_mvm_sta_modify_disable_tx_ap(struct iwl_mvm *mvm,
 void iwl_mvm_modify_all_sta_disable_tx(struct iwl_mvm *mvm,
                                        struct iwl_mvm_vif *mvmvif,
                                        bool disable);
+void iwl_mvm_csa_client_absent(struct iwl_mvm *mvm, struct ieee80211_vif *vif);
 
 #endif /* __sta_h__ */
diff --git a/drivers/net/wireless/iwlwifi/mvm/time-event.c b/drivers/net/wireless/iwlwifi/mvm/time-event.c
index 8cf246b695c4..1a537be216ce 100644
--- a/drivers/net/wireless/iwlwifi/mvm/time-event.c
+++ b/drivers/net/wireless/iwlwifi/mvm/time-event.c
@@ -191,6 +191,33 @@ static bool iwl_mvm_te_check_disconnect(struct iwl_mvm *mvm,
         return true;
 }
 
+static void
+iwl_mvm_te_handle_notify_csa(struct iwl_mvm *mvm,
+                             struct iwl_mvm_time_event_data *te_data,
+                             struct iwl_time_event_notif *notif)
+{
+        if (!le32_to_cpu(notif->status)) {
+                IWL_DEBUG_TE(mvm, "CSA time event failed to start\n");
+                return;
+        }
+
+        switch (te_data->vif->type) {
+        case NL80211_IFTYPE_AP:
+                iwl_mvm_csa_noa_start(mvm);
+                break;
+        case NL80211_IFTYPE_STATION:
+                iwl_mvm_csa_client_absent(mvm, te_data->vif);
+                break;
+        default:
+                /* should never happen */
+                WARN_ON_ONCE(1);
+                break;
+        }
+
+        /* we don't need it anymore */
+        iwl_mvm_te_clear_data(mvm, te_data);
+}
+
 /*
  * Handles a FW notification for an event that is known to the driver.
  *
@@ -252,14 +279,8 @@ static void iwl_mvm_te_handle_notif(struct iwl_mvm *mvm,
                         set_bit(IWL_MVM_STATUS_ROC_RUNNING, &mvm->status);
                         iwl_mvm_ref(mvm, IWL_MVM_REF_ROC);
                         ieee80211_ready_on_channel(mvm->hw);
-                } else if (te_data->vif->type == NL80211_IFTYPE_AP) {
-                        if (le32_to_cpu(notif->status))
-                                iwl_mvm_csa_noa_start(mvm);
-                        else
-                                IWL_DEBUG_TE(mvm, "CSA NOA failed to start\n");
-
-                        /* we don't need it anymore */
-                        iwl_mvm_te_clear_data(mvm, te_data);
+                } else if (te_data->id == TE_CHANNEL_SWITCH_PERIOD) {
+                        iwl_mvm_te_handle_notify_csa(mvm, te_data, notif);
                 }
         } else {
                 IWL_WARN(mvm, "Got TE with unknown action\n");