iwlwifi: make TX seqno validation more efficient

Accessing the device in Tx path is not a good idea.
Mirror the data in DRAM.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/pcie/internal.h

@@ -217,6 +217,7 @@ struct iwl_pcie_txq_scratch_buf {
  * @trans_pcie: pointer back to transport (for timer)
  * @need_update: indicates need to update read/write index
  * @active: stores if queue is active
+ * @ampdu: true if this queue is an ampdu queue for an specific RA/TID
  *
  * A Tx queue consists of circular buffer of BDs (a.k.a. TFDs, transmit frame
  * descriptors) and required locking structures.
@@ -232,6 +233,7 @@ struct iwl_txq {
 	struct iwl_trans_pcie *trans_pcie;
 	u8 need_update;
 	u8 active;
+	bool ampdu;
 };
 
 static inline dma_addr_t

drivers/net/wireless/iwlwifi/pcie/tx.c

@@ -1073,6 +1073,7 @@ void iwl_trans_pcie_txq_enable(struct iwl_trans *trans, int txq_id, int fifo,
 
 		/* enable aggregations for the queue */
 		iwl_set_bits_prph(trans, SCD_AGGR_SEL, BIT(txq_id));
+		trans_pcie->txq[txq_id].ampdu = true;
 	} else {
 		/*
 		 * disable aggregations for the queue, this will also make the
@@ -1129,6 +1130,7 @@ void iwl_trans_pcie_txq_disable(struct iwl_trans *trans, int txq_id)
 			    ARRAY_SIZE(zero_val));
 
 	iwl_pcie_txq_unmap(trans, txq_id);
+	trans_pcie->txq[txq_id].ampdu = false;
 
 	IWL_DEBUG_TX_QUEUES(trans, "Deactivate queue %d\n", txq_id);
 }
@@ -1599,7 +1601,7 @@ int iwl_trans_pcie_tx(struct iwl_trans *trans, struct sk_buff *skb,
 	u8 wait_write_ptr = 0;
 	__le16 fc = hdr->frame_control;
 	u8 hdr_len = ieee80211_hdrlen(fc);
-	u16 __maybe_unused wifi_seq;
+	u16 wifi_seq;
 
 	txq = &trans_pcie->txq[txq_id];
 	q = &txq->q;
@@ -1616,13 +1618,11 @@ int iwl_trans_pcie_tx(struct iwl_trans *trans, struct sk_buff *skb,
 	 * the BA.
 	 * Check here that the packets are in the right place on the ring.
 	 */
-#ifdef CONFIG_IWLWIFI_DEBUG
 	wifi_seq = IEEE80211_SEQ_TO_SN(le16_to_cpu(hdr->seq_ctrl));
-	WARN_ONCE((iwl_read_prph(trans, SCD_AGGR_SEL) & BIT(txq_id)) &&
-		  ((wifi_seq & 0xff) != q->write_ptr),
+	WARN_ONCE(trans_pcie->txq[txq_id].ampdu &&
+		  (wifi_seq & 0xff) != q->write_ptr,
 		  "Q: %d WiFi Seq %d tfdNum %d",
 		  txq_id, wifi_seq, q->write_ptr);
-#endif
 
 	/* Set up driver data for this TFD */
 	txq->entries[q->write_ptr].skb = skb;