mac80211: add a HW flag for supporting HW TX fragmentation

Currently mac80211 determines whether HW does fragmentation
by checking whether the set_frag_threshold callback is set
or not.
However, some drivers may want to set the HW fragmentation
capability depending on HW generation.
Allow this by checking a HW flag instead of checking the
callback.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
[added the flag to ath10k and wlcore]
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index f56e2f4..e02ba42 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -210,6 +210,7 @@ static const char *hw_flag_names[] = {
 	FLAG(TX_AMSDU),
 	FLAG(TX_FRAG_LIST),
 	FLAG(REPORTS_LOW_ACK),
+	FLAG(SUPPORTS_TX_FRAG),
 #undef FLAG
 };
 
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 1075ac2..0d9163c 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -821,6 +821,10 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 	     !local->ops->tdls_recv_channel_switch))
 		return -EOPNOTSUPP;
 
+	if (WARN_ON(ieee80211_hw_check(hw, SUPPORTS_TX_FRAG) &&
+		    !local->ops->set_frag_threshold))
+		return -EINVAL;
+
 	if (WARN_ON(local->hw.wiphy->interface_modes &
 			BIT(NL80211_IFTYPE_NAN) &&
 		    (!local->ops->start_nan || !local->ops->stop_nan)))
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 772e369..62ccaf6 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -934,7 +934,7 @@ ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
 	if (info->flags & IEEE80211_TX_CTL_DONTFRAG)
 		return TX_CONTINUE;
 
-	if (tx->local->ops->set_frag_threshold)
+	if (ieee80211_hw_check(&tx->local->hw, SUPPORTS_TX_FRAG))
 		return TX_CONTINUE;
 
 	/*
@@ -2800,7 +2800,7 @@ void ieee80211_check_fast_xmit(struct sta_info *sta)
 
 	/* fast-xmit doesn't handle fragmentation at all */
 	if (local->hw.wiphy->frag_threshold != (u32)-1 &&
-	    !local->ops->set_frag_threshold)
+	    !ieee80211_hw_check(&local->hw, SUPPORTS_TX_FRAG))
 		goto out;
 
 	rcu_read_lock();
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index b48c1e1..c249345 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -57,7 +57,7 @@ ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
 
 	if (info->control.hw_key &&
 	    (info->flags & IEEE80211_TX_CTL_DONTFRAG ||
-	     tx->local->ops->set_frag_threshold) &&
+	     ieee80211_hw_check(&tx->local->hw, SUPPORTS_TX_FRAG)) &&
 	    !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
 		/* hwaccel - with no need for SW-generated MMIC */
 		return TX_CONTINUE;