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>

drivers/net/wireless/ath/ath10k/mac.c

@@ -7881,6 +7881,7 @@ int ath10k_mac_register(struct ath10k *ar)
 	ieee80211_hw_set(ar->hw, WANT_MONITOR_VIF);
 	ieee80211_hw_set(ar->hw, CHANCTX_STA_CSA);
 	ieee80211_hw_set(ar->hw, QUEUE_CONTROL);
+	ieee80211_hw_set(ar->hw, SUPPORTS_TX_FRAG);
 
 	if (!test_bit(ATH10K_FLAG_RAW_MODE, &ar->dev_flags))
 		ieee80211_hw_set(ar->hw, SW_CRYPTO_CONTROL);

drivers/net/wireless/ti/wlcore/main.c

@@ -6086,6 +6086,7 @@ static int wl1271_init_ieee80211(struct wl1271 *wl)
 	ieee80211_hw_set(wl->hw, SUPPORTS_DYNAMIC_PS);
 	ieee80211_hw_set(wl->hw, SIGNAL_DBM);
 	ieee80211_hw_set(wl->hw, SUPPORTS_PS);
+	ieee80211_hw_set(wl->hw, SUPPORTS_TX_FRAG);
 
 	wl->hw->wiphy->cipher_suites = cipher_suites;
 	wl->hw->wiphy->n_cipher_suites = ARRAY_SIZE(cipher_suites);

include/net/mac80211.h

@@ -2025,6 +2025,10 @@ struct ieee80211_txq {
  *	drivers, mac80211 packet loss mechanism will not be triggered and driver
  *	is completely depending on firmware event for station kickout.
  *
+ * @IEEE80211_HW_SUPPORTS_TX_FRAG: Hardware does fragmentation by itself.
+ *	The stack will not do fragmentation.
+ *	The callback for @set_frag_threshold should be set as well.
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
@@ -2066,6 +2070,7 @@ enum ieee80211_hw_flags {
 	IEEE80211_HW_TX_AMSDU,
 	IEEE80211_HW_TX_FRAG_LIST,
 	IEEE80211_HW_REPORTS_LOW_ACK,
+	IEEE80211_HW_SUPPORTS_TX_FRAG,
 
 	/* keep last, obviously */
 	NUM_IEEE80211_HW_FLAGS
@@ -3093,8 +3098,9 @@ enum ieee80211_reconfig_type {
  *	The callback must be atomic.
  *
  * @set_frag_threshold: Configuration of fragmentation threshold. Assign this
- *	if the device does fragmentation by itself; if this callback is
+ *	if the device does fragmentation by itself. Note that to prevent the
- *	implemented then the stack will not do fragmentation.
+ *	stack from doing fragmentation IEEE80211_HW_SUPPORTS_TX_FRAG
+ *	should be set as well.
  *	The callback can sleep.
  *
  * @set_rts_threshold: Configuration of RTS threshold (if device needs it)

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
 };
 

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)))

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();

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;