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From:   Wen Gong <quic_wgong@quicinc.com>
To:     <ath12k@lists.infradead.org>
CC:     <linux-wireless@vger.kernel.org>, <quic_wgong@quicinc.com>
Subject: [PATCH v2] wifi: ath12k: trigger station disconnect on hardware restart
Date:   Fri, 14 Jul 2023 05:25:55 -0400
Message-ID: <20230714092555.2018-1-quic_wgong@quicinc.com>
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Currently after the hardware restart triggered from the driver, the
station interface connection remains intact, since a disconnect
trigger is not sent to userspace. This can lead to a problem in
targets where the wifi mac sequence is added by the firmware.

After the target restart, its wifi mac sequence number gets reset to
zero. Hence AP to which our device is connected will receive frames
with a wifi mac sequence number jump to the past, thereby resulting
in the AP dropping all these frames, until the frame arrives with a
wifi mac sequence number which AP was expecting.

To avoid such frame drops, its better to trigger a station disconnect
upon target hardware restart which can be done with API
ieee80211_reconfig_disconnect exposed to mac80211.

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

Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
---
v2: add code comment explaining why disconnect needs to be done.

 drivers/net/wireless/ath/ath12k/mac.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index ee792822b411..044a5901a2a0 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -6364,6 +6364,7 @@ ath12k_mac_op_reconfig_complete(struct ieee80211_hw *hw,
 {
 	struct ath12k *ar = hw->priv;
 	struct ath12k_base *ab = ar->ab;
+	struct ath12k_vif *arvif;
 	int recovery_count;
 
 	if (reconfig_type != IEEE80211_RECONFIG_TYPE_RESTART)
@@ -6392,6 +6393,27 @@ ath12k_mac_op_reconfig_complete(struct ieee80211_hw *hw,
 				ath12k_dbg(ab, ATH12K_DBG_BOOT, "reset success\n");
 			}
 		}
+
+		list_for_each_entry(arvif, &ar->arvifs, list) {
+			ath12k_dbg(ab, ATH12K_DBG_BOOT,
+				   "reconfig cipher %d up %d vdev type %d\n",
+				   arvif->key_cipher,
+				   arvif->is_up,
+				   arvif->vdev_type);
+			/*
+			 * After trigger disconnect, then upper layer will
+			 * trigger connect again, then the PN number of
+			 * upper layer will be reset to keep up with AP
+			 * side, hence PN number mis-match will not happened.
+			 */
+			if (arvif->is_up &&
+			    arvif->vdev_type == WMI_VDEV_TYPE_STA &&
+			    arvif->vdev_subtype == WMI_VDEV_SUBTYPE_NONE) {
+				ieee80211_hw_restart_disconnect(arvif->vif);
+				ath12k_dbg(ab, ATH12K_DBG_BOOT,
+					   "restart disconnect\n");
+			}
+		}
 	}
 
 	mutex_unlock(&ar->conf_mutex);

base-commit: 0a00db612b6df1fad80485e3642529d1f28ea084
-- 
2.40.1