[RFC PATCH] wifi: ath10k: support flush_sta method

[Zhi-Jun You <hujy652@gmail.com>]

When a STA is marked as no longer authorized, if the driver doesn't
implement flush_sta(), mac80211 calls ieee80211_flush_queues() to
flush hardware queues to avoid sending unencrypted frames.

This has became a problem for ath10k because ieee80211_flush_queues()
will stop all traffic and call ath10k_flush, which waits until the
whole HW queue is empty. In a busy environment this will trigger a
timeout warning and stalls other STAs.

Fix this by implementing flush_sta method using WMI command to flush
frames of a specific STA.
Flushed frames will be marked as discard in tx complete indication.

ops->flush_sta will be set to NULL if htt.disable_tx_comp is set to
true.

Tested-on: QCA9984 hw1.0 PCI 10.4-3.9.0.2-00157

Signed-off-by: Zhi-Jun You <hujy652@gmail.com>
---
 drivers/net/wireless/ath/ath10k/mac.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 24dd794e31ea..6959f20334a7 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -8135,6 +8135,20 @@ static void ath10k_flush(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	mutex_unlock(&ar->conf_mutex);
 }
 
+static void ath10k_mac_op_flush_sta(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
+			     struct ieee80211_sta *sta)
+{
+	struct ath10k_vif *arvif = (void *)vif->drv_priv;
+	struct ath10k *ar = hw->priv;
+	u32 bitmap = 0xFFFFFFFF;
+	int ret = 0;
+
+	ret = ath10k_wmi_peer_flush(ar, arvif->vdev_id, sta->addr, bitmap);
+	if (ret)
+		ath10k_warn(ar, "failed to flush sta (sta %pM)\n",
+			    sta->addr);
+}
+
 /* TODO: Implement this function properly
  * For now it is needed to reply to Probe Requests in IBSS mode.
  * Probably we need this information from FW.
@@ -9487,6 +9501,7 @@ static const struct ieee80211_ops ath10k_ops = {
 	.set_rts_threshold		= ath10k_set_rts_threshold,
 	.set_frag_threshold		= ath10k_mac_op_set_frag_threshold,
 	.flush				= ath10k_flush,
+	.flush_sta			= ath10k_mac_op_flush_sta,
 	.tx_last_beacon			= ath10k_tx_last_beacon,
 	.set_antenna			= ath10k_set_antenna,
 	.get_antenna			= ath10k_get_antenna,
@@ -10294,6 +10309,9 @@ int ath10k_mac_register(struct ath10k *ar)
 	if (!ar->hw_params.hw_ops->set_coverage_class)
 		ar->ops->set_coverage_class = NULL;
 
+	if (ar->htt.disable_tx_comp)
+		ar->ops->flush_sta = NULL;
+
 	ret = ath_regd_init(&ar->ath_common.regulatory, ar->hw->wiphy,
 			    ath10k_reg_notifier);
 	if (ret) {
-- 
2.50.1