/******************************************************************************
   *
   * This file is provided under a dual BSD/GPLv2 license.  When using or
   * redistributing this file, you may do so under either license.
   *
   * GPL LICENSE SUMMARY
   *
   * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
   * Copyright(c) 2013 - 2014 Intel Mobile Communications GmbH
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of version 2 of the GNU General Public License as
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   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
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   * You should have received a copy of the GNU General Public License
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   * USA
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   * The full GNU General Public License is included in this distribution
   * in the file called COPYING.
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   * Contact Information:
   *  Intel Linux Wireless <ilw@linux.intel.com>
   * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
   *
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   *
   * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
   * Copyright(c) 2013 - 2014 Intel Mobile Communications GmbH
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   *****************************************************************************/
  
  #ifndef __sta_h__
  #define __sta_h__
  
  #include <linux/spinlock.h>
  #include <net/mac80211.h>
  #include <linux/wait.h>
  
  #include "iwl-trans.h" /* for IWL_MAX_TID_COUNT */
  #include "fw-api.h" /* IWL_MVM_STATION_COUNT */
  #include "rs.h"
  
  struct iwl_mvm;
  struct iwl_mvm_vif;
  
  /**
   * DOC: station table - introduction
   *
   * The station table is a list of data structure that reprensent the stations.
   * In STA/P2P client mode, the driver will hold one station for the AP/ GO.
   * In GO/AP mode, the driver will have as many stations as associated clients.
   * All these stations are reflected in the fw's station table. The driver
   * keeps the fw's station table up to date with the ADD_STA command. Stations
   * can be removed by the REMOVE_STA command.
   *
   * All the data related to a station is held in the structure %iwl_mvm_sta
   * which is embed in the mac80211's %ieee80211_sta (in the drv_priv) area.
   * This data includes the index of the station in the fw, per tid information
   * (sequence numbers, Block-ack state machine, etc...). The stations are
   * created and deleted by the %sta_state callback from %ieee80211_ops.
   *
   * The driver holds a map: %fw_id_to_mac_id that allows to fetch a
   * %ieee80211_sta (and the %iwl_mvm_sta embedded into it) based on a fw
   * station index. That way, the driver is able to get the tid related data in
   * O(1) in time sensitive paths (Tx / Tx response / BA notification). These
   * paths are triggered by the fw, and the driver needs to get a pointer to the
   * %ieee80211 structure. This map helps to get that pointer quickly.
   */
  
  /**
   * DOC: station table - locking
   *
   * As stated before, the station is created / deleted by mac80211's %sta_state
   * callback from %ieee80211_ops which can sleep. The next paragraph explains
   * the locking of a single stations, the next ones relates to the station
   * table.
   *
   * The station holds the sequence number per tid. So this data needs to be
   * accessed in the Tx path (which is softIRQ). It also holds the Block-Ack
   * information (the state machine / and the logic that checks if the queues
   * were drained), so it also needs to be accessible from the Tx response flow.
   * In short, the station needs to be access from sleepable context as well as
   * from tasklets, so the station itself needs a spinlock.
   *
   * The writers of %fw_id_to_mac_id map are serialized by the global mutex of
   * the mvm op_mode. This is possible since %sta_state can sleep.
   * The pointers in this map are RCU protected, hence we won't replace the
   * station while we have Tx / Tx response / BA notification running.
   *
   * If a station is deleted while it still has packets in its A-MPDU queues,
   * then the reclaim flow will notice that there is no station in the map for
   * sta_id and it will dump the responses.
   */
  
  /**
   * DOC: station table - internal stations
   *
   * The FW needs a few internal stations that are not reflected in
   * mac80211, such as broadcast station in AP / GO mode, or AUX sta for
   * scanning and P2P device (during the GO negotiation).
   * For these kind of stations we have %iwl_mvm_int_sta struct which holds the
   * data relevant for them from both %iwl_mvm_sta and %ieee80211_sta.
   * Usually the data for these stations is static, so no locking is required,
   * and no TID data as this is also not needed.
   * One thing to note, is that these stations have an ID in the fw, but not
   * in mac80211. In order to "reserve" them a sta_id in %fw_id_to_mac_id
   * we fill ERR_PTR(EINVAL) in this mapping and all other dereferencing of
   * pointers from this mapping need to check that the value is not error
   * or NULL.
   *
   * Currently there is only one auxiliary station for scanning, initialized
   * on init.
   */
  
  /**
   * DOC: station table - AP Station in STA mode
   *
   * %iwl_mvm_vif includes the index of the AP station in the fw's STA table:
   * %ap_sta_id. To get the point to the corresponding %ieee80211_sta,
   * &fw_id_to_mac_id can be used. Due to the way the fw works, we must not remove
   * the AP station from the fw before setting the MAC context as unassociated.
   * Hence, %fw_id_to_mac_id[%ap_sta_id] will be NULLed when the AP station is
   * removed by mac80211, but the station won't be removed in the fw until the
   * VIF is set as unassociated. Then, %ap_sta_id will be invalidated.
   */
  
  /**
   * DOC: station table - Drain vs. Flush
   *
   * Flush means that all the frames in the SCD queue are dumped regardless the
   * station to which they were sent. We do that when we disassociate and before
   * we remove the STA of the AP. The flush can be done synchronously against the
   * fw.
   * Drain means that the fw will drop all the frames sent to a specific station.
   * This is useful when a client (if we are IBSS / GO or AP) disassociates. In
   * that case, we need to drain all the frames for that client from the AC queues
   * that are shared with the other clients. Only then, we can remove the STA in
   * the fw. In order to do so, we track the non-AMPDU packets for each station.
   * If mac80211 removes a STA and if it still has non-AMPDU packets pending in
   * the queues, we mark this station as %EBUSY in %fw_id_to_mac_id, and drop all
   * the frames for this STA (%iwl_mvm_rm_sta). When the last frame is dropped
   * (we know about it with its Tx response), we remove the station in fw and set
   * it as %NULL in %fw_id_to_mac_id: this is the purpose of
   * %iwl_mvm_sta_drained_wk.
   */
  
  /**
   * DOC: station table - fw restart
   *
   * When the fw asserts, or we have any other issue that requires to reset the
   * driver, we require mac80211 to reconfigure the driver. Since the private
   * data of the stations is embed in mac80211's %ieee80211_sta, that data will
   * not be zeroed and needs to be reinitialized manually.
   * %IWL_MVM_STATUS_IN_HW_RESTART is set during restart and that will hint us
   * that we must not allocate a new sta_id but reuse the previous one. This
   * means that the stations being re-added after the reset will have the same
   * place in the fw as before the reset. We do need to zero the %fw_id_to_mac_id
   * map, since the stations aren't in the fw any more. Internal stations that
   * are not added by mac80211 will be re-added in the init flow that is called
   * after the restart: mac80211 call's %iwl_mvm_mac_start which calls to
   * %iwl_mvm_up.
   */
  
  /**
   * DOC: AP mode - PS
   *
   * When a station is asleep, the fw will set it as "asleep". All frames on
   * shared queues (i.e. non-aggregation queues) to that station will be dropped
   * by the fw (%TX_STATUS_FAIL_DEST_PS failure code).
   *
   * AMPDUs are in a separate queue that is stopped by the fw. We just need to
   * let mac80211 know when there are frames in these queues so that it can
   * properly handle trigger frames.
   *
   * When a trigger frame is received, mac80211 tells the driver to send frames
   * from the AMPDU queues or sends frames to non-aggregation queues itself,
   * depending on which ACs are delivery-enabled and what TID has frames to
   * transmit. Note that mac80211 has all the knowledge since all the non-agg
   * frames are buffered / filtered, and the driver tells mac80211 about agg
   * frames). The driver needs to tell the fw to let frames out even if the
   * station is asleep. This is done by %iwl_mvm_sta_modify_sleep_tx_count.
   *
   * When we receive a frame from that station with PM bit unset, the driver
   * needs to let the fw know that this station isn't asleep any more. This is
   * done by %iwl_mvm_sta_modify_ps_wake in response to mac80211 signaling the
   * station's wakeup.
   *
   * For a GO, the Service Period might be cut short due to an absence period
   * of the GO. In this (and all other cases) the firmware notifies us with the
   * EOSP_NOTIFICATION, and we notify mac80211 of that. Further frames that we
   * already sent to the device will be rejected again.
   *
   * See also "AP support for powersaving clients" in mac80211.h.
   */
  
  /**
   * enum iwl_mvm_agg_state
   *
   * The state machine of the BA agreement establishment / tear down.
   * These states relate to a specific RA / TID.
   *
   * @IWL_AGG_OFF: aggregation is not used
   * @IWL_AGG_STARTING: aggregation are starting (between start and oper)
   * @IWL_AGG_ON: aggregation session is up
   * @IWL_EMPTYING_HW_QUEUE_ADDBA: establishing a BA session - waiting for the
   *	HW queue to be empty from packets for this RA /TID.
   * @IWL_EMPTYING_HW_QUEUE_DELBA: tearing down a BA session - waiting for the
   *	HW queue to be empty from packets for this RA /TID.
   */
  enum iwl_mvm_agg_state {
  	IWL_AGG_OFF = 0,
  	IWL_AGG_STARTING,
  	IWL_AGG_ON,
  	IWL_EMPTYING_HW_QUEUE_ADDBA,
  	IWL_EMPTYING_HW_QUEUE_DELBA,
  };
  
  /**
   * struct iwl_mvm_tid_data - holds the states for each RA / TID
   * @seq_number: the next WiFi sequence number to use
   * @next_reclaimed: the WiFi sequence number of the next packet to be acked.
   *	This is basically (last acked packet++).
   * @rate_n_flags: Rate at which Tx was attempted. Holds the data between the
   *	Tx response (TX_CMD), and the block ack notification (COMPRESSED_BA).
   * @reduced_tpc: Reduced tx power. Holds the data between the
   *	Tx response (TX_CMD), and the block ack notification (COMPRESSED_BA).
   * @state: state of the BA agreement establishment / tear down.
   * @txq_id: Tx queue used by the BA session
   * @ssn: the first packet to be sent in AGG HW queue in Tx AGG start flow, or
   *	the first packet to be sent in legacy HW queue in Tx AGG stop flow.
   *	Basically when next_reclaimed reaches ssn, we can tell mac80211 that
   *	we are ready to finish the Tx AGG stop / start flow.
   * @tx_time: medium time consumed by this A-MPDU
   */
  struct iwl_mvm_tid_data {
  	u16 seq_number;
  	u16 next_reclaimed;
  	/* The rest is Tx AGG related */
  	u32 rate_n_flags;
  	u8 reduced_tpc;
  	enum iwl_mvm_agg_state state;
  	u16 txq_id;
  	u16 ssn;
  	u16 tx_time;
  };
  
  static inline u16 iwl_mvm_tid_queued(struct iwl_mvm_tid_data *tid_data)
  {
  	return ieee80211_sn_sub(IEEE80211_SEQ_TO_SN(tid_data->seq_number),
  				tid_data->next_reclaimed);
  }
  
  /**
   * struct iwl_mvm_sta - representation of a station in the driver
   * @sta_id: the index of the station in the fw (will be replaced by id_n_color)
   * @tfd_queue_msk: the tfd queues used by the station
   * @hw_queue: per-AC mapping of the TFD queues used by station
   * @mac_id_n_color: the MAC context this station is linked to
   * @tid_disable_agg: bitmap: if bit(tid) is set, the fw won't send ampdus for
   *	tid.
   * @max_agg_bufsize: the maximal size of the AGG buffer for this station
   * @bt_reduced_txpower: is reduced tx power enabled for this station
   * @next_status_eosp: the next reclaimed packet is a PS-Poll response and
   *	we need to signal the EOSP
   * @lock: lock to protect the whole struct. Since %tid_data is access from Tx
   * and from Tx response flow, it needs a spinlock.
   * @tid_data: per tid data. Look at %iwl_mvm_tid_data.
   * @tx_protection: reference counter for controlling the Tx protection.
   * @tt_tx_protection: is thermal throttling enable Tx protection?
   * @disable_tx: is tx to this STA disabled?
   * @agg_tids: bitmap of tids whose status is operational aggregated (IWL_AGG_ON)
   *
   * When mac80211 creates a station it reserves some space (hw->sta_data_size)
   * in the structure for use by driver. This structure is placed in that
   * space.
   *
   */
  struct iwl_mvm_sta {
  	u32 sta_id;
  	u32 tfd_queue_msk;
  	u8 hw_queue[IEEE80211_NUM_ACS];
  	u32 mac_id_n_color;
  	u16 tid_disable_agg;
  	u8 max_agg_bufsize;
  	bool bt_reduced_txpower;
  	bool next_status_eosp;
  	spinlock_t lock;
  	struct iwl_mvm_tid_data tid_data[IWL_MAX_TID_COUNT];
  	struct iwl_lq_sta lq_sta;
  	struct ieee80211_vif *vif;
  
  	/* Temporary, until the new TLC will control the Tx protection */
  	s8 tx_protection;
  	bool tt_tx_protection;
  
  	bool disable_tx;
  	u8 agg_tids;
  };
  
  static inline struct iwl_mvm_sta *
  iwl_mvm_sta_from_mac80211(struct ieee80211_sta *sta)
  {
  	return (void *)sta->drv_priv;
  }
  
  /**
   * struct iwl_mvm_int_sta - representation of an internal station (auxiliary or
   * broadcast)
   * @sta_id: the index of the station in the fw (will be replaced by id_n_color)
   * @tfd_queue_msk: the tfd queues used by the station
   */
  struct iwl_mvm_int_sta {
  	u32 sta_id;
  	u32 tfd_queue_msk;
  };
  
  int iwl_mvm_sta_send_to_fw(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
  			   bool update);
  int iwl_mvm_add_sta(struct iwl_mvm *mvm,
  		    struct ieee80211_vif *vif,
  		    struct ieee80211_sta *sta);
  int iwl_mvm_update_sta(struct iwl_mvm *mvm,
  		       struct ieee80211_vif *vif,
  		       struct ieee80211_sta *sta);
  int iwl_mvm_rm_sta(struct iwl_mvm *mvm,
  		   struct ieee80211_vif *vif,
  		   struct ieee80211_sta *sta);
  int iwl_mvm_rm_sta_id(struct iwl_mvm *mvm,
  		      struct ieee80211_vif *vif,
  		      u8 sta_id);
  int iwl_mvm_set_sta_key(struct iwl_mvm *mvm,
  			struct ieee80211_vif *vif,
  			struct ieee80211_sta *sta,
  			struct ieee80211_key_conf *keyconf,
  			u8 key_offset);
  int iwl_mvm_remove_sta_key(struct iwl_mvm *mvm,
  			   struct ieee80211_vif *vif,
  			   struct ieee80211_sta *sta,
  			   struct ieee80211_key_conf *keyconf);
  
  void iwl_mvm_update_tkip_key(struct iwl_mvm *mvm,
  			     struct ieee80211_vif *vif,
  			     struct ieee80211_key_conf *keyconf,
  			     struct ieee80211_sta *sta, u32 iv32,
  			     u16 *phase1key);
  
  void iwl_mvm_rx_eosp_notif(struct iwl_mvm *mvm,
  			   struct iwl_rx_cmd_buffer *rxb);
  
  /* AMPDU */
  int iwl_mvm_sta_rx_agg(struct iwl_mvm *mvm, struct ieee80211_sta *sta,
  		       int tid, u16 ssn, bool start);
  int iwl_mvm_sta_tx_agg_start(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
  			struct ieee80211_sta *sta, u16 tid, u16 *ssn);
  int iwl_mvm_sta_tx_agg_oper(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
  			struct ieee80211_sta *sta, u16 tid, u8 buf_size);
  int iwl_mvm_sta_tx_agg_stop(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
  			    struct ieee80211_sta *sta, u16 tid);
  int iwl_mvm_sta_tx_agg_flush(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
  			    struct ieee80211_sta *sta, u16 tid);
  
  int iwl_mvm_add_aux_sta(struct iwl_mvm *mvm);
  void iwl_mvm_del_aux_sta(struct iwl_mvm *mvm);
  
  int iwl_mvm_alloc_bcast_sta(struct iwl_mvm *mvm, struct ieee80211_vif *vif);
  int iwl_mvm_send_add_bcast_sta(struct iwl_mvm *mvm, struct ieee80211_vif *vif);
  int iwl_mvm_add_bcast_sta(struct iwl_mvm *mvm, struct ieee80211_vif *vif);
  int iwl_mvm_send_rm_bcast_sta(struct iwl_mvm *mvm, struct ieee80211_vif *vif);
  int iwl_mvm_rm_bcast_sta(struct iwl_mvm *mvm, struct ieee80211_vif *vif);
  void iwl_mvm_dealloc_bcast_sta(struct iwl_mvm *mvm, struct ieee80211_vif *vif);
  
  void iwl_mvm_sta_drained_wk(struct work_struct *wk);
  void iwl_mvm_sta_modify_ps_wake(struct iwl_mvm *mvm,
  				struct ieee80211_sta *sta);
  void iwl_mvm_sta_modify_sleep_tx_count(struct iwl_mvm *mvm,
  				       struct ieee80211_sta *sta,
  				       enum ieee80211_frame_release_type reason,
  				       u16 cnt, u16 tids, bool more_data,
  				       bool agg);
  int iwl_mvm_drain_sta(struct iwl_mvm *mvm, struct iwl_mvm_sta *mvmsta,
  		      bool drain);
  void iwl_mvm_sta_modify_disable_tx(struct iwl_mvm *mvm,
  				   struct iwl_mvm_sta *mvmsta, bool disable);
  void iwl_mvm_sta_modify_disable_tx_ap(struct iwl_mvm *mvm,
  				      struct ieee80211_sta *sta,
  				      bool disable);
  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__ */