wifi: ath12k: Add lock to protect the hardware state

Currently, hardware state is not protected across the reconfigure
operations. However, in single wiphy models, multiple radio/links is
exposed as a MAC hardware (ieee80211_hw) through the driver hardware
abstraction (ath12k_hw) layer. In such scenario, we need to protect
hardware state across the multiple radio/link at the driver hardware
abstraction (ath12k_hw) layer. Therefore, introduce a new mutex in
the ath12k_hw layer.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
Signed-off-by: Karthikeyan Periyasamy <quic_periyasa@quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240425090307.3233434-4-quic_periyasa@quicinc.com

drivers/net/wireless/ath/ath12k/core.c

@@ -1048,6 +1048,8 @@ static void ath12k_core_post_reconfigure_recovery(struct ath12k_base *ab)
 		if (!ah || ah->state == ATH12K_HW_STATE_OFF)
 			continue;
 
+		mutex_lock(&ah->hw_mutex);
+
 		switch (ah->state) {
 		case ATH12K_HW_STATE_ON:
 			ah->state = ATH12K_HW_STATE_RESTARTING;
@@ -1078,6 +1080,8 @@ static void ath12k_core_post_reconfigure_recovery(struct ath12k_base *ab)
 				    "device is wedged, will not restart hw %d\n", i);
 			break;
 		}
+
+		mutex_unlock(&ah->hw_mutex);
 	}
 
 	complete(&ab->driver_recovery);

drivers/net/wireless/ath/ath12k/core.h

@@ -636,11 +636,17 @@ struct ath12k {
 struct ath12k_hw {
 	struct ieee80211_hw *hw;
 	struct ath12k_base *ab;
+
+	/* Protect the write operation of the hardware state ath12k_hw::state
+	 * between hardware start<=>reconfigure<=>stop transitions.
+	 */
+	struct mutex hw_mutex;
 	enum ath12k_hw_state state;
 	bool regd_updated;
 	bool use_6ghz_regd;
 	u8 num_radio;
 
+	/* Keep last */
 	struct ath12k radio[] __aligned(sizeof(void *));
 };
 

drivers/net/wireless/ath/ath12k/mac.c

@@ -5615,10 +5615,13 @@ static void ath12k_mac_wait_reconfigure(struct ath12k_base *ab)
 
 static int ath12k_mac_start(struct ath12k *ar)
 {
+	struct ath12k_hw *ah = ar->ah;
 	struct ath12k_base *ab = ar->ab;
 	struct ath12k_pdev *pdev = ar->pdev;
 	int ret;
 
+	lockdep_assert_held(&ah->hw_mutex);
+
 	mutex_lock(&ar->conf_mutex);
 
 	ret = ath12k_wmi_pdev_set_param(ar, WMI_PDEV_PARAM_PMF_QOS,
@@ -5733,6 +5736,8 @@ static int ath12k_mac_op_start(struct ieee80211_hw *hw)
 
 	ath12k_drain_tx(ah);
 
+	guard(mutex)(&ah->hw_mutex);
+
 	switch (ah->state) {
 	case ATH12K_HW_STATE_OFF:
 		ah->state = ATH12K_HW_STATE_ON;
@@ -5831,9 +5836,12 @@ int ath12k_mac_rfkill_enable_radio(struct ath12k *ar, bool enable)
 
 static void ath12k_mac_stop(struct ath12k *ar)
 {
+	struct ath12k_hw *ah = ar->ah;
 	struct htt_ppdu_stats_info *ppdu_stats, *tmp;
 	int ret;
 
+	lockdep_assert_held(&ah->hw_mutex);
+
 	mutex_lock(&ar->conf_mutex);
 	ret = ath12k_mac_config_mon_status_default(ar, false);
 	if (ret && (ret != -EOPNOTSUPP))
@@ -5869,10 +5877,14 @@ static void ath12k_mac_op_stop(struct ieee80211_hw *hw)
 
 	ath12k_drain_tx(ah);
 
+	mutex_lock(&ah->hw_mutex);
+
 	ah->state = ATH12K_HW_STATE_OFF;
 
 	for_each_ar(ah, ar, i)
 		ath12k_mac_stop(ar);
+
+	mutex_unlock(&ah->hw_mutex);
 }
 
 static u8
@@ -7931,6 +7943,8 @@ ath12k_mac_op_reconfig_complete(struct ieee80211_hw *hw,
 	if (reconfig_type != IEEE80211_RECONFIG_TYPE_RESTART)
 		return;
 
+	guard(mutex)(&ah->hw_mutex);
+
 	if (ah->state != ATH12K_HW_STATE_RESTARTED)
 		return;
 
@@ -8933,6 +8947,8 @@ static struct ath12k_hw *ath12k_mac_hw_allocate(struct ath12k_base *ab,
 	ah->ab = ab;
 	ah->num_radio = num_pdev_map;
 
+	mutex_init(&ah->hw_mutex);
+
 	for (i = 0; i < num_pdev_map; i++) {
 		ab = pdev_map[i].ab;
 		pdev_idx = pdev_map[i].pdev_idx;