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>

1 files changed, 24 insertions, 3 deletions

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)
 {