iwlwifi: mvm: implement driver RX queues sync command

mac80211 will call the driver whenever there is a race between
RSS queues and control path that requires a processing of all
pending frames in RSS queues.
Implement that by utilizing the internal notification mechanism:
queue a message to all queues. When the message is received on
a queue it decrements the atomic counter. This guarantees that
all pending frames in the RX queue were processed since the message
is in order inside the queue.
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/fw-api-rx.h

@@ -437,9 +437,11 @@ struct iwl_rxq_sync_notification {
 /**
 * Internal message identifier
 *
+* @IWL_MVM_RXQ_SYNC: sync RSS queues
 * @IWL_MVM_RXQ_NOTIF_DEL_BA: notify RSS queues of delBA
 */
 enum iwl_mvm_rxq_notif_type {
+	IWL_MVM_RXQ_SYNC,
 	IWL_MVM_RXQ_NOTIF_DEL_BA,
 };
 
@@ -448,10 +450,12 @@ enum iwl_mvm_rxq_notif_type {
 * in &iwl_rxq_sync_cmd. Should be DWORD aligned.
 *
 * @type: value from &iwl_mvm_rxq_notif_type
+* @cookie: internal cookie to identify old notifications
 * @data: payload
 */
 struct iwl_mvm_internal_rxq_notif {
 	u32 type;
+	u32 cookie;
 	u8 data[];
 } __packed;
 

drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c

@@ -4037,6 +4037,47 @@ static void iwl_mvm_mac_event_callback(struct ieee80211_hw *hw,
 	}
 }
 
+static void iwl_mvm_sync_rx_queues_internal(struct iwl_mvm *mvm)
+{
+	struct iwl_mvm_internal_rxq_notif data = {
+		.type = IWL_MVM_RXQ_SYNC,
+		.cookie = mvm->queue_sync_cookie,
+	};
+	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(notif_waitq);
+	u32 qmask = BIT(mvm->trans->num_rx_queues) - 1;
+	int ret;
+
+	lockdep_assert_held(&mvm->mutex);
+
+	if (!iwl_mvm_has_new_rx_api(mvm))
+		return;
+
+	atomic_set(&mvm->queue_sync_counter, mvm->trans->num_rx_queues);
+
+	ret = iwl_mvm_notify_rx_queue(mvm, qmask, (u8 *)&data, sizeof(data));
+	if (ret) {
+		IWL_ERR(mvm, "Failed to trigger RX queues sync (%d)\n", ret);
+		goto out;
+	}
+	ret = wait_event_timeout(notif_waitq,
+				 atomic_read(&mvm->queue_sync_counter) == 0,
+				 HZ);
+	WARN_ON_ONCE(!ret);
+
+out:
+	atomic_set(&mvm->queue_sync_counter, 0);
+	mvm->queue_sync_cookie++;
+}
+
+static void iwl_mvm_sync_rx_queues(struct ieee80211_hw *hw)
+{
+	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
+
+	mutex_lock(&mvm->mutex);
+	iwl_mvm_sync_rx_queues_internal(mvm);
+	mutex_unlock(&mvm->mutex);
+}
+
 const struct ieee80211_ops iwl_mvm_hw_ops = {
 	.tx = iwl_mvm_mac_tx,
 	.ampdu_action = iwl_mvm_mac_ampdu_action,
@@ -4093,6 +4134,8 @@ const struct ieee80211_ops iwl_mvm_hw_ops = {
 
 	.event_callback = iwl_mvm_mac_event_callback,
 
+	.sync_rx_queues = iwl_mvm_sync_rx_queues,
+
 	CFG80211_TESTMODE_CMD(iwl_mvm_mac_testmode_cmd)
 
 #ifdef CONFIG_PM_SLEEP

drivers/net/wireless/intel/iwlwifi/mvm/mvm.h

@@ -633,6 +633,8 @@ struct iwl_mvm {
 
 	unsigned long status;
 
+	u32 queue_sync_cookie;
+	atomic_t queue_sync_counter;
 	/*
 	 * for beacon filtering -
 	 * currently only one interface can be supported

drivers/net/wireless/intel/iwlwifi/mvm/ops.c

@@ -586,6 +586,8 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
 	skb_queue_head_init(&mvm->d0i3_tx);
 	init_waitqueue_head(&mvm->d0i3_exit_waitq);
 
+	atomic_set(&mvm->queue_sync_counter, 0);
+
 	SET_IEEE80211_DEV(mvm->hw, mvm->trans->dev);
 
 	/*

drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c

@@ -406,6 +406,13 @@ void iwl_mvm_rx_queue_notif(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
 	internal_notif = (void *)notif->payload;
 
 	switch (internal_notif->type) {
+	case IWL_MVM_RXQ_SYNC:
+		if (mvm->queue_sync_cookie == internal_notif->cookie)
+			atomic_dec(&mvm->queue_sync_counter);
+		else
+			WARN_ONCE(1,
+				  "Received expired RX queue sync message\n");
+		break;
 	case IWL_MVM_RXQ_NOTIF_DEL_BA:
 		/* TODO */
 		break;