rt2x00: rt2800: use correct txop value in tx descriptor

rt2800 devices use a different enumeration to specify what IFS values should
be used on frame transmission compared to the other rt2x00 devices. Hence,
create a new enum called txop that contains the valid values.

Furthermore use the appropriate txop values as found in the ralink drivers:
- TXOP_BACKOFF for management frames
- TXOP_SIFS for subsequent fragments in a burst
- TXOP_HTTXOP for all data frames

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2x00ht.c b/drivers/net/wireless/rt2x00/rt2x00ht.c
index 1056c92143a..5a407602ce3 100644
--- a/drivers/net/wireless/rt2x00/rt2x00ht.c
+++ b/drivers/net/wireless/rt2x00/rt2x00ht.c
@@ -35,6 +35,7 @@ void rt2x00ht_create_tx_descriptor(struct queue_entry *entry,
 {
 	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(entry->skb);
 	struct ieee80211_tx_rate *txrate = &tx_info->control.rates[0];
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)entry->skb->data;
 
 	if (tx_info->control.sta)
 		txdesc->mpdu_density =
@@ -66,4 +67,20 @@ void rt2x00ht_create_tx_descriptor(struct queue_entry *entry,
 		__set_bit(ENTRY_TXD_HT_BW_40, &txdesc->flags);
 	if (txrate->flags & IEEE80211_TX_RC_SHORT_GI)
 		__set_bit(ENTRY_TXD_HT_SHORT_GI, &txdesc->flags);
+
+	/*
+	 * Determine IFS values
+	 * - Use TXOP_BACKOFF for management frames
+	 * - Use TXOP_SIFS for fragment bursts
+	 * - Use TXOP_HTTXOP for everything else
+	 *
+	 * Note: rt2800 devices won't use CTS protection (if used)
+	 * for frames not transmitted with TXOP_HTTXOP
+	 */
+	if (ieee80211_is_mgmt(hdr->frame_control))
+		txdesc->txop = TXOP_BACKOFF;
+	else if (!(tx_info->flags & IEEE80211_TX_CTL_FIRST_FRAGMENT))
+		txdesc->txop = TXOP_SIFS;
+	else
+		txdesc->txop = TXOP_HTTXOP;
 }