iwlwifi: mvm: support dqa-mode scd queue redirection

Make sure that in DQA mode, the SCD's configuration of a
queue is redirected to the lower AC of the streams of the
queue.

Make sure that this queue is redirected to the lowest AC
when adding a new RA/TID to an existing queue. If it isn't -
redirect the queue.

Also, as redirection revealed a bug in the marking of a
shared queue, this patch contains a small fix to make
sure a shared queue maintains the appropriate "shared queue
marking".

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
index 1617de7..a6d6df9 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/sta.c
@@ -513,6 +513,101 @@ static int iwl_mvm_get_shared_queue(struct iwl_mvm *mvm,
        return queue;
 }
 
+/*
+ * If a given queue has a higher AC than the TID stream that is being added to
+ * it, the queue needs to be redirected to the lower AC. This function does that
+ * in such a case, otherwise - if no redirection required - it does nothing,
+ * unless the %force param is true.
+ */
+static int iwl_mvm_scd_queue_redirect(struct iwl_mvm *mvm, int queue, int tid,
+                                     int ac, int ssn, unsigned int wdg_timeout,
+                                     bool force)
+{
+       struct iwl_scd_txq_cfg_cmd cmd = {
+               .scd_queue = queue,
+               .enable = 0,
+       };
+       bool shared_queue;
+       unsigned long mq;
+       int ret;
+
+       /*
+        * If the AC is lower than current one - FIFO needs to be redirected to
+        * the lowest one of the streams in the queue. Check if this is needed
+        * here.
+        * Notice that the enum ieee80211_ac_numbers is "flipped", so BK is with
+        * value 3 and VO with value 0, so to check if ac X is lower than ac Y
+        * we need to check if the numerical value of X is LARGER than of Y.
+        */
+       spin_lock_bh(&mvm->queue_info_lock);
+       if (ac <= mvm->queue_info[queue].mac80211_ac && !force) {
+               spin_unlock_bh(&mvm->queue_info_lock);
+
+               IWL_DEBUG_TX_QUEUES(mvm,
+                                   "No redirection needed on TXQ #%d\n",
+                                   queue);
+               return 0;
+       }
+
+       cmd.sta_id = mvm->queue_info[queue].ra_sta_id;
+       cmd.tx_fifo = iwl_mvm_ac_to_tx_fifo[mvm->queue_info[queue].mac80211_ac];
+       mq = mvm->queue_info[queue].hw_queue_to_mac80211;
+       shared_queue = (mvm->queue_info[queue].hw_queue_refcount > 1);
+       spin_unlock_bh(&mvm->queue_info_lock);
+
+       IWL_DEBUG_TX_QUEUES(mvm, "Redirecting shared TXQ #%d to FIFO #%d\n",
+                           queue, iwl_mvm_ac_to_tx_fifo[ac]);
+
+       /* Stop MAC queues and wait for this queue to empty */
+       iwl_mvm_stop_mac_queues(mvm, mq);
+       ret = iwl_trans_wait_tx_queue_empty(mvm->trans, BIT(queue));
+       if (ret) {
+               IWL_ERR(mvm, "Error draining queue %d before reconfig\n",
+                       queue);
+               ret = -EIO;
+               goto out;
+       }
+
+       /* Before redirecting the queue we need to de-activate it */
+       iwl_trans_txq_disable(mvm->trans, queue, false);
+       ret = iwl_mvm_send_cmd_pdu(mvm, SCD_QUEUE_CFG, 0, sizeof(cmd), &cmd);
+       if (ret)
+               IWL_ERR(mvm, "Failed SCD disable TXQ %d (ret=%d)\n", queue,
+                       ret);
+
+       /* Make sure the SCD wrptr is correctly set before reconfiguring */
+       iwl_trans_txq_enable(mvm->trans, queue, iwl_mvm_ac_to_tx_fifo[ac],
+                            cmd.sta_id, tid, LINK_QUAL_AGG_FRAME_LIMIT_DEF,
+                            ssn, wdg_timeout);
+
+       /* TODO: Work-around SCD bug when moving back by multiples of 0x40 */
+
+       /* Redirect to lower AC */
+       iwl_mvm_reconfig_scd(mvm, queue, iwl_mvm_ac_to_tx_fifo[ac],
+                            cmd.sta_id, tid, LINK_QUAL_AGG_FRAME_LIMIT_DEF,
+                            ssn);
+
+       /* Update AC marking of the queue */
+       spin_lock_bh(&mvm->queue_info_lock);
+       mvm->queue_info[queue].mac80211_ac = ac;
+       spin_unlock_bh(&mvm->queue_info_lock);
+
+       /*
+        * Mark queue as shared in transport if shared
+        * Note this has to be done after queue enablement because enablement
+        * can also set this value, and there is no indication there to shared
+        * queues
+        */
+       if (shared_queue)
+               iwl_trans_txq_set_shared_mode(mvm->trans, queue, true);
+
+out:
+       /* Continue using the MAC queues */
+       iwl_mvm_start_mac_queues(mvm, mq);
+
+       return ret;
+}
+
 static int iwl_mvm_sta_alloc_queue(struct iwl_mvm *mvm,
                                   struct ieee80211_sta *sta, u8 ac, int tid,
                                   struct ieee80211_hdr *hdr)
@@ -680,17 +775,21 @@ static int iwl_mvm_sta_alloc_queue(struct iwl_mvm *mvm,
                        iwl_mvm_invalidate_sta_queue(mvm, queue,
                                                     disable_agg_tids, false);
                }
-
-               /* Mark queue as shared in transport */
-               iwl_trans_txq_set_shared_mode(mvm->trans, queue, true);
-
-               /* TODO: a redirection may be required - DQA phase 2 */
        }
 
        ssn = IEEE80211_SEQ_TO_SN(le16_to_cpu(hdr->seq_ctrl));
        iwl_mvm_enable_txq(mvm, queue, mac_queue, ssn, &cfg,
                           wdg_timeout);
 
+       /*
+        * Mark queue as shared in transport if shared
+        * Note this has to be done after queue enablement because enablement
+        * can also set this value, and there is no indication there to shared
+        * queues
+        */
+       if (shared_queue)
+               iwl_trans_txq_set_shared_mode(mvm->trans, queue, true);
+
        spin_lock_bh(&mvmsta->lock);
        mvmsta->tid_data[tid].txq_id = queue;
        mvmsta->tid_data[tid].is_tid_active = true;
@@ -712,6 +811,12 @@ static int iwl_mvm_sta_alloc_queue(struct iwl_mvm *mvm,
                        if (ret)
                                goto out_err;
                }
+       } else {
+               /* Redirect queue, if needed */
+               ret = iwl_mvm_scd_queue_redirect(mvm, queue, tid, ac, ssn,
+                                                wdg_timeout, false);
+               if (ret)
+                       goto out_err;
        }
 
        return 0;