wcn36xx: Use correct SSN for ADD BA request

Since firmware uses its own sequence number counters, we need to
use firmware number as well when mac80211 generates the ADD_BA
request packet. Indeed the firmware sequence counters tend to
slightly drift from the mac80211 ones because of firmware offload
features like ARP responses. This causes the starting sequence
number field of the ADD_BA request to be unaligned, and can possibly
cause issues with strict/picky APs.

To fix this, we retrieve the current firmware sequence number for
a given TID through the smd_trigger_ba API, and use that number as
replacement of the mac80211 starting sequence number.

This change also ensures that any issue in the smd *ba procedures
will cause the ba action to properly fail, and remove useless call
to smd_trigger_ba() from IEEE80211_AMPDU_RX_START.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1637604251-11763-1-git-send-email-loic.poulain@linaro.org

drivers/net/wireless/ath/wcn36xx/main.c

@@ -1220,7 +1220,7 @@ static int wcn36xx_ampdu_action(struct ieee80211_hw *hw,
 	u16 tid = params->tid;
 	u16 *ssn = &params->ssn;
 	int ret = 0;
-	u8 session;
+	int session;
 
 	wcn36xx_dbg(WCN36XX_DBG_MAC, "mac ampdu action action %d tid %d\n",
 		    action, tid);
@@ -1232,9 +1232,11 @@ static int wcn36xx_ampdu_action(struct ieee80211_hw *hw,
 		sta_priv->tid = tid;
 		session = wcn36xx_smd_add_ba_session(wcn, sta, tid, ssn, 0,
 						     get_sta_index(vif, sta_priv));
+		if (session < 0) {
+			ret = session;
+			goto out;
+		}
 		wcn36xx_smd_add_ba(wcn, session);
-		wcn36xx_smd_trigger_ba(wcn, get_sta_index(vif, sta_priv), tid,
-				       session);
 		break;
 	case IEEE80211_AMPDU_RX_STOP:
 		wcn36xx_smd_del_ba(wcn, tid, 0, get_sta_index(vif, sta_priv));
@@ -1244,6 +1246,18 @@ static int wcn36xx_ampdu_action(struct ieee80211_hw *hw,
 		sta_priv->ampdu_state[tid] = WCN36XX_AMPDU_START;
 		spin_unlock_bh(&sta_priv->ampdu_lock);
 
+		/* Replace the mac80211 ssn with the firmware one */
+		wcn36xx_dbg(WCN36XX_DBG_MAC, "mac ampdu ssn = %u\n", *ssn);
+		wcn36xx_smd_trigger_ba(wcn, get_sta_index(vif, sta_priv), tid, ssn);
+		wcn36xx_dbg(WCN36XX_DBG_MAC, "mac ampdu fw-ssn = %u\n", *ssn);
+
+		/* Start BA session */
+		session = wcn36xx_smd_add_ba_session(wcn, sta, tid, ssn, 1,
+						     get_sta_index(vif, sta_priv));
+		if (session < 0) {
+			ret = session;
+			goto out;
+		}
 		ret = IEEE80211_AMPDU_TX_START_IMMEDIATE;
 		break;
 	case IEEE80211_AMPDU_TX_OPERATIONAL:
@@ -1251,8 +1265,6 @@ static int wcn36xx_ampdu_action(struct ieee80211_hw *hw,
 		sta_priv->ampdu_state[tid] = WCN36XX_AMPDU_OPERATIONAL;
 		spin_unlock_bh(&sta_priv->ampdu_lock);
 
-		wcn36xx_smd_add_ba_session(wcn, sta, tid, ssn, 1,
-			get_sta_index(vif, sta_priv));
 		break;
 	case IEEE80211_AMPDU_TX_STOP_FLUSH:
 	case IEEE80211_AMPDU_TX_STOP_FLUSH_CONT:
@@ -1268,6 +1280,7 @@ static int wcn36xx_ampdu_action(struct ieee80211_hw *hw,
 		wcn36xx_err("Unknown AMPDU action\n");
 	}
 
+out:
 	mutex_unlock(&wcn->conf_mutex);
 
 	return ret;

drivers/net/wireless/ath/wcn36xx/smd.c

@@ -2561,6 +2561,7 @@ int wcn36xx_smd_add_ba_session(struct wcn36xx *wcn,
 					     &session_id);
 	if (ret) {
 		wcn36xx_err("hal_add_ba_session response failed err=%d\n", ret);
+		ret = -EINVAL;
 		goto out;
 	}
 
@@ -2626,27 +2627,43 @@ int wcn36xx_smd_del_ba(struct wcn36xx *wcn, u16 tid, u8 direction, u8 sta_index)
 	return ret;
 }
 
-static int wcn36xx_smd_trigger_ba_rsp(void *buf, int len)
+static int wcn36xx_smd_trigger_ba_rsp(void *buf, int len, struct add_ba_info *ba_info)
 {
+	struct wcn36xx_hal_trigger_ba_rsp_candidate *candidate;
 	struct wcn36xx_hal_trigger_ba_rsp_msg *rsp;
+	int i;
 
 	if (len < sizeof(*rsp))
 		return -EINVAL;
 
 	rsp = (struct wcn36xx_hal_trigger_ba_rsp_msg *) buf;
+
+	if (rsp->candidate_cnt < 1)
+		return rsp->status ? rsp->status : -EINVAL;
+
+	candidate = (struct wcn36xx_hal_trigger_ba_rsp_candidate *)(buf + sizeof(*rsp));
+
+	for (i = 0; i < STACFG_MAX_TC; i++) {
+		ba_info[i] = candidate->ba_info[i];
+	}
+
 	return rsp->status;
 }
 
-int wcn36xx_smd_trigger_ba(struct wcn36xx *wcn, u8 sta_index, u16 tid, u8 session_id)
+int wcn36xx_smd_trigger_ba(struct wcn36xx *wcn, u8 sta_index, u16 tid, u16 *ssn)
 {
 	struct wcn36xx_hal_trigger_ba_req_msg msg_body;
 	struct wcn36xx_hal_trigger_ba_req_candidate *candidate;
+	struct add_ba_info ba_info[STACFG_MAX_TC];
 	int ret;
 
+	if (tid >= STACFG_MAX_TC)
+		return -EINVAL;
+
 	mutex_lock(&wcn->hal_mutex);
 	INIT_HAL_MSG(msg_body, WCN36XX_HAL_TRIGGER_BA_REQ);
 
-	msg_body.session_id = session_id;
+	msg_body.session_id = 0; /* not really used */
 	msg_body.candidate_cnt = 1;
 	msg_body.header.len += sizeof(*candidate);
 	PREPARE_HAL_BUF(wcn->hal_buf, msg_body);
@@ -2661,13 +2678,17 @@ int wcn36xx_smd_trigger_ba(struct wcn36xx *wcn, u8 sta_index, u16 tid, u8 sessio
 		wcn36xx_err("Sending hal_trigger_ba failed\n");
 		goto out;
 	}
-	ret = wcn36xx_smd_trigger_ba_rsp(wcn->hal_buf, wcn->hal_rsp_len);
+	ret = wcn36xx_smd_trigger_ba_rsp(wcn->hal_buf, wcn->hal_rsp_len, ba_info);
 	if (ret) {
 		wcn36xx_err("hal_trigger_ba response failed err=%d\n", ret);
 		goto out;
 	}
 out:
 	mutex_unlock(&wcn->hal_mutex);
+
+	if (ssn)
+		*ssn = ba_info[tid].starting_seq_num;
+
 	return ret;
 }
 

drivers/net/wireless/ath/wcn36xx/smd.h

@@ -137,7 +137,7 @@ int wcn36xx_smd_add_ba_session(struct wcn36xx *wcn,
 		u8 sta_index);
 int wcn36xx_smd_add_ba(struct wcn36xx *wcn, u8 session_id);
 int wcn36xx_smd_del_ba(struct wcn36xx *wcn, u16 tid, u8 direction, u8 sta_index);
-int wcn36xx_smd_trigger_ba(struct wcn36xx *wcn, u8 sta_index, u16 tid, u8 session_id);
+int wcn36xx_smd_trigger_ba(struct wcn36xx *wcn, u8 sta_index, u16 tid, u16 *ssn);
 
 int wcn36xx_smd_update_cfg(struct wcn36xx *wcn, u32 cfg_id, u32 value);