mac80211: support hw managing reorder logic

Enable driver to manage the reordering logic itself.
This is needed for example for the iwlwifi driver that
will support hardware assisted reordering.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

4 files changed, 41 insertions, 11 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 6c9c559394b0..ee6305a52251 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1929,6 +1929,11 @@ struct ieee80211_txq {
  *      by just its MAC address; this prevents, for example, the same station
  *      from connecting to two virtual AP interfaces at the same time.
  *
+ * @IEEE80211_HW_SUPPORTS_REORDERING_BUFFER: Hardware (or driver) manages the
+ *      reordering buffer internally, guaranteeing mac80211 receives frames in
+ *      order and does not need to manage its own reorder buffer or BA session
+ *      timeout.
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
@@ -1965,6 +1970,7 @@ enum ieee80211_hw_flags {
         IEEE80211_HW_SUPPORTS_AMSDU_IN_AMPDU,
         IEEE80211_HW_BEACON_TX_STATUS,
         IEEE80211_HW_NEEDS_UNIQUE_STA_ADDR,
+        IEEE80211_HW_SUPPORTS_REORDERING_BUFFER,
 
         /* keep last, obviously */
         NUM_IEEE80211_HW_FLAGS
diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index ec80db7c955c..2ab54791281d 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -76,10 +76,11 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
         tid_rx = rcu_dereference_protected(sta->ampdu_mlme.tid_rx[tid],
                                         lockdep_is_held(&sta->ampdu_mlme.mtx));
 
-        if (!tid_rx)
+        if (!test_bit(tid, sta->ampdu_mlme.agg_session_valid))
                 return;
 
         RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
+        __clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
 
         ht_dbg(sta->sdata,
                "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
@@ -97,6 +98,13 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
                 ieee80211_send_delba(sta->sdata, sta->sta.addr,
                                      tid, WLAN_BACK_RECIPIENT, reason);
 
+        /*
+         * return here in case tid_rx is not assigned - which will happen if
+         * IEEE80211_HW_SUPPORTS_REORDERING_BUFFER is set.
+         */
+        if (!tid_rx)
+                return;
+
         del_timer_sync(&tid_rx->session_timer);
 
         /* make sure ieee80211_sta_reorder_release() doesn't re-arm the timer */
@@ -297,7 +305,7 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta,
         /* examine state machine */
         mutex_lock(&sta->ampdu_mlme.mtx);
 
-        if (sta->ampdu_mlme.tid_rx[tid]) {
+        if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) {
                 ht_dbg_ratelimited(sta->sdata,
                                    "unexpected AddBA Req from %pM on tid %u\n",
                                    sta->sta.addr, tid);
@@ -308,6 +316,16 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta,
                                                 false);
         }
 
+        if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
+                ret = drv_ampdu_action(local, sta->sdata, &params);
+                ht_dbg(sta->sdata,
+                       "Rx A-MPDU request on %pM tid %d result %d\n",
+                       sta->sta.addr, tid, ret);
+                if (!ret)
+                        status = WLAN_STATUS_SUCCESS;
+                goto end;
+        }
+
         /* prepare A-MPDU MLME for Rx aggregation */
         tid_agg_rx = kmalloc(sizeof(struct tid_ampdu_rx), GFP_KERNEL);
         if (!tid_agg_rx)
@@ -369,6 +387,8 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta,
         }
 
 end:
+        if (status == WLAN_STATUS_SUCCESS)
+                __set_bit(tid, sta->ampdu_mlme.agg_session_valid);
         mutex_unlock(&sta->ampdu_mlme.mtx);
 
 end_no_lock:
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index abbdff03ce92..e433d0c97e86 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -126,6 +126,7 @@ static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = {
         FLAG(SUPPORTS_AMSDU_IN_AMPDU),
         FLAG(BEACON_TX_STATUS),
         FLAG(NEEDS_UNIQUE_STA_ADDR),
+        FLAG(SUPPORTS_REORDERING_BUFFER),
 
         /* keep last for the build bug below */
         (void *)0x1
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index d6051629ed15..f4d38994ecee 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -1,6 +1,7 @@
 /*
  * Copyright 2002-2005, Devicescape Software, Inc.
  * Copyright 2013-2014  Intel Mobile Communications GmbH
+ * Copyright(c) 2015 Intel Deutschland GmbH
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -212,20 +213,21 @@ struct tid_ampdu_rx {
 /**
  * struct sta_ampdu_mlme - STA aggregation information.
  *
+ * @mtx: mutex to protect all TX data (except non-NULL assignments
+ *      to tid_tx[idx], which are protected by the sta spinlock)
+ *      tid_start_tx is also protected by sta->lock.
  * @tid_rx: aggregation info for Rx per TID -- RCU protected
- * @tid_tx: aggregation info for Tx per TID
- * @tid_start_tx: sessions where start was requested
- * @addba_req_num: number of times addBA request has been sent.
- * @last_addba_req_time: timestamp of the last addBA request.
- * @dialog_token_allocator: dialog token enumerator for each new session;
- * @work: work struct for starting/stopping aggregation
  * @tid_rx_timer_expired: bitmap indicating on which TIDs the
  *      RX timer expired until the work for it runs
  * @tid_rx_stop_requested:  bitmap indicating which BA sessions per TID the
  *      driver requested to close until the work for it runs
- * @mtx: mutex to protect all TX data (except non-NULL assignments
- *      to tid_tx[idx], which are protected by the sta spinlock)
- *      tid_start_tx is also protected by sta->lock.
+ * @agg_session_valid: bitmap indicating which TID has a rx BA session open on
+ * @work: work struct for starting/stopping aggregation
+ * @tid_tx: aggregation info for Tx per TID
+ * @tid_start_tx: sessions where start was requested
+ * @last_addba_req_time: timestamp of the last addBA request.
+ * @addba_req_num: number of times addBA request has been sent.
+ * @dialog_token_allocator: dialog token enumerator for each new session;
  */
 struct sta_ampdu_mlme {
         struct mutex mtx;
@@ -233,6 +235,7 @@ struct sta_ampdu_mlme {
         struct tid_ampdu_rx __rcu *tid_rx[IEEE80211_NUM_TIDS];
         unsigned long tid_rx_timer_expired[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
         unsigned long tid_rx_stop_requested[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
+        unsigned long agg_session_valid[BITS_TO_LONGS(IEEE80211_NUM_TIDS)];
         /* tx */
         struct work_struct work;
         struct tid_ampdu_tx __rcu *tid_tx[IEEE80211_NUM_TIDS];