[PATCH] wcn36xx: Fix discarded frames due to wrong sequence number

[Loic Poulain]

The firmware is offering features such as ARP offload, for which
firmware crafts its own (QoS)packets without waking up the host.
Point is that the sequence numbers generated by the firmware are
not in sync with the host mac80211 layer and can cause packets
such as firmware ARP reponses to be dropped by the AP (too old SN).

To fix this we need to let the firmware manages the sequence
numbers by its own (except for QoS null frames). There is a SN
counter for each QoS queue and one global/baseline counter for
Non-QoS.

Fixes: 84aff52e4f57 ("wcn36xx: Use sequence number allocated by mac80211")
Signed-off-by: Loic Poulain <loic.poulain at linaro.org>
---
 drivers/net/wireless/ath/wcn36xx/txrx.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/wcn36xx/txrx.c b/drivers/net/wireless/ath/wcn36xx/txrx.c
index 81db90f..75951cc 100644
--- a/drivers/net/wireless/ath/wcn36xx/txrx.c
+++ b/drivers/net/wireless/ath/wcn36xx/txrx.c
@@ -427,8 +427,6 @@ static void wcn36xx_set_tx_pdu(struct wcn36xx_tx_bd *bd,
 		bd->pdu.mpdu_header_off;
 	bd->pdu.mpdu_len = len;
 	bd->pdu.tid = tid;
-	/* Use seq number generated by mac80211 */
-	bd->pdu.bd_ssn = WCN36XX_TXBD_SSN_FILL_HOST;
 }
 
 static inline struct wcn36xx_vif *get_vif_by_addr(struct wcn36xx *wcn,
@@ -525,6 +523,9 @@ static void wcn36xx_set_tx_data(struct wcn36xx_tx_bd *bd,
 		tid = ieee80211_get_tid(hdr);
 		/* TID->QID is one-to-one mapping */
 		bd->queue_id = tid;
+		bd->pdu.bd_ssn = WCN36XX_TXBD_SSN_FILL_DPU_QOS;
+	} else {
+		bd->pdu.bd_ssn = WCN36XX_TXBD_SSN_FILL_DPU_NON_QOS;
 	}
 
 	if (info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT ||
@@ -536,6 +537,8 @@ static void wcn36xx_set_tx_data(struct wcn36xx_tx_bd *bd,
 		/* Don't use a regular queue for null packet (no ampdu) */
 		bd->queue_id = WCN36XX_TX_U_WQ_ID;
 		bd->bd_rate = WCN36XX_BD_RATE_CTRL;
+		if (ieee80211_is_qos_nullfunc(hdr->frame_control))
+			bd->pdu.bd_ssn = WCN36XX_TXBD_SSN_FILL_HOST;
 	}
 
 	if (bcast) {
@@ -595,6 +598,8 @@ static void wcn36xx_set_tx_mgmt(struct wcn36xx_tx_bd *bd,
 		bd->queue_id = WCN36XX_TX_U_WQ_ID;
 	*vif_priv = __vif_priv;
 
+	bd->pdu.bd_ssn = WCN36XX_TXBD_SSN_FILL_DPU_NON_QOS;
+
 	wcn36xx_set_tx_pdu(bd,
 			   ieee80211_is_data_qos(hdr->frame_control) ?
 			   sizeof(struct ieee80211_qos_hdr) :
-- 
2.7.4