[RFC 1/3] wifi: ath12k: Flush all packets before suspend

[Baochen Qiang <quic_bqiang@xxxxxxxxxxx>]

In order to send out all packets before going to suspend, current code
adds a 500ms delay as a workaround. It is a rough estimate and may not
work.

The logic of the fix is to check packet counters, if counters become
zero, then all packets are sent out or dropped.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0-03427-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.15378.4

Signed-off-by: Baochen Qiang <quic_bqiang@xxxxxxxxxxx>
---
 drivers/net/wireless/ath/ath12k/core.c | 17 +++++++---
 drivers/net/wireless/ath/ath12k/mac.c  | 44 +++++++++++++++++++-------
 drivers/net/wireless/ath/ath12k/mac.h  |  1 +
 3 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/core.c b/drivers/net/wireless/ath/ath12k/core.c
index 3df8059d5512..73065d38be2d 100644
--- a/drivers/net/wireless/ath/ath12k/core.c
+++ b/drivers/net/wireless/ath/ath12k/core.c
@@ -21,15 +21,22 @@ MODULE_PARM_DESC(debug_mask, "Debugging mask");
 
 int ath12k_core_suspend(struct ath12k_base *ab)
 {
-	int ret;
+	struct ath12k *ar;
+	int ret, i;
 
 	if (!ab->hw_params->supports_suspend)
 		return -EOPNOTSUPP;
 
-	/* TODO: there can frames in queues so for now add delay as a hack.
-	 * Need to implement to handle and remove this delay.
-	 */
-	msleep(500);
+	for (i = 0; i < ab->num_radios; i++) {
+		ar = ab->pdevs[i].ar;
+		if (!ar)
+			continue;
+		ret = ath12k_mac_wait_tx_complete(ar);
+		if (ret) {
+			ath12k_warn(ab, "failed to wait tx complete: %d\n", ret);
+			return ret;
+		}
+	}
 
 	ret = ath12k_dp_rx_pktlog_stop(ab, true);
 	if (ret) {
diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index 1bb9802ef569..3e472afe09b1 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -6017,27 +6017,49 @@ static int ath12k_mac_op_set_frag_threshold(struct ieee80211_hw *hw, u32 value)
 	return -EOPNOTSUPP;
 }
 
-static void ath12k_mac_op_flush(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
-				u32 queues, bool drop)
+static int ath12k_mac_flush_tx_complete(struct ath12k *ar)
 {
-	struct ath12k *ar = hw->priv;
 	long time_left;
-
-	if (drop)
-		return;
+	int ret = 0;
 
 	time_left = wait_event_timeout(ar->dp.tx_empty_waitq,
 				       (atomic_read(&ar->dp.num_tx_pending) == 0),
 				       ATH12K_FLUSH_TIMEOUT);
-	if (time_left == 0)
-		ath12k_warn(ar->ab, "failed to flush transmit queue %ld\n", time_left);
+	if (time_left == 0) {
+		ath12k_warn(ar->ab,
+			    "failed to flush transmit queue, data pkts pending %d\n",
+			    atomic_read(&ar->dp.num_tx_pending));
+		ret = -ETIMEDOUT;
+	}
 
 	time_left = wait_event_timeout(ar->txmgmt_empty_waitq,
 				       (atomic_read(&ar->num_pending_mgmt_tx) == 0),
 				       ATH12K_FLUSH_TIMEOUT);
-	if (time_left == 0)
-		ath12k_warn(ar->ab, "failed to flush mgmt transmit queue %ld\n",
-			    time_left);
+	if (time_left == 0) {
+		ath12k_warn(ar->ab,
+			    "failed to flush mgmt transmit queue, mgmt pkts pending %d\n",
+			    atomic_read(&ar->num_pending_mgmt_tx));
+		ret = -ETIMEDOUT;
+	}
+
+	return ret;
+}
+
+int ath12k_mac_wait_tx_complete(struct ath12k *ar)
+{
+	ath12k_mac_drain_tx(ar);
+	return ath12k_mac_flush_tx_complete(ar);
+}
+
+static void ath12k_mac_op_flush(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
+				u32 queues, bool drop)
+{
+	struct ath12k *ar = hw->priv;
+
+	if (drop)
+		return;
+
+	ath12k_mac_flush_tx_complete(ar);
 }
 
 static int
diff --git a/drivers/net/wireless/ath/ath12k/mac.h b/drivers/net/wireless/ath/ath12k/mac.h
index 57f4295420bb..d0d48133e926 100644
--- a/drivers/net/wireless/ath/ath12k/mac.h
+++ b/drivers/net/wireless/ath/ath12k/mac.h
@@ -73,4 +73,5 @@ int ath12k_mac_tx_mgmt_pending_free(int buf_id, void *skb, void *ctx);
 enum rate_info_bw ath12k_mac_bw_to_mac80211_bw(enum ath12k_supported_bw bw);
 enum ath12k_supported_bw ath12k_mac_mac80211_bw_to_ath12k_bw(enum rate_info_bw bw);
 enum hal_encrypt_type ath12k_dp_tx_get_encrypt_type(u32 cipher);
+int ath12k_mac_wait_tx_complete(struct ath12k *ar);
 #endif
-- 
2.25.1