iwlwifi: mvm: Allow P2P Device to use an existing PHY context

The patch is an optimization, that eliminates unnecessary binding
context switching and allows the P2P Device MAC to use the same channel
as an existing netdev interface.

For each ROC call, check if there is already a channel/phy context that
can be used for the P2P Device. If such channel is found, unbind
the P2P Device from its current phy context, and bind it to the already
used channel/phy context. In case that the phy context is shared,
and there is a need to change it, create a new phy context, unbind and
create a new binding.
Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

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

@@ -1194,28 +1194,105 @@ static int iwl_mvm_roc(struct ieee80211_hw *hw,
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
 	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
 	struct cfg80211_chan_def chandef;
-	int ret;
+	struct iwl_mvm_phy_ctxt *phy_ctxt;
+	int ret, i;
+
+	IWL_DEBUG_MAC80211(mvm, "enter (%d, %d, %d)\n", channel->hw_value,
+			   duration, type);
 
 	if (vif->type != NL80211_IFTYPE_P2P_DEVICE) {
 		IWL_ERR(mvm, "vif isn't a P2P_DEVICE: %d\n", vif->type);
 		return -EINVAL;
 	}
 
-	IWL_DEBUG_MAC80211(mvm, "enter (%d, %d, %d)\n", channel->hw_value,
-			   duration, type);
-
 	mutex_lock(&mvm->mutex);
 
+	for (i = 0; i < NUM_PHY_CTX; i++) {
+		phy_ctxt = &mvm->phy_ctxts[i];
+		if (phy_ctxt->ref == 0 || mvmvif->phy_ctxt == phy_ctxt)
+			continue;
+
+		if (phy_ctxt->ref && channel == phy_ctxt->channel) {
+			/*
+			 * Unbind the P2P_DEVICE from the current PHY context,
+			 * and if the PHY context is not used remove it.
+			 */
+			ret = iwl_mvm_binding_remove_vif(mvm, vif);
+			if (WARN(ret, "Failed unbinding P2P_DEVICE\n"))
+				goto out_unlock;
+
+			iwl_mvm_phy_ctxt_unref(mvm, mvmvif->phy_ctxt);
+
+			/* Bind the P2P_DEVICE to the current PHY Context */
+			mvmvif->phy_ctxt = phy_ctxt;
+
+			ret = iwl_mvm_binding_add_vif(mvm, vif);
+			if (WARN(ret, "Failed binding P2P_DEVICE\n"))
+				goto out_unlock;
+
+			iwl_mvm_phy_ctxt_ref(mvm, mvmvif->phy_ctxt);
+			goto schedule_time_event;
+		}
+	}
+
+	/* Need to update the PHY context only if the ROC channel changed */
+	if (channel == mvmvif->phy_ctxt->channel)
+		goto schedule_time_event;
+
 	cfg80211_chandef_create(&chandef, channel, NL80211_CHAN_NO_HT);
-	ret = iwl_mvm_phy_ctxt_changed(mvm, mvmvif->phy_ctxt,
-				       &chandef, 1, 1);
 
+	/*
+	 * Change the PHY context configuration as it is currently referenced
+	 * only by the P2P Device MAC
+	 */
+	if (mvmvif->phy_ctxt->ref == 1) {
+		ret = iwl_mvm_phy_ctxt_changed(mvm, mvmvif->phy_ctxt,
+					       &chandef, 1, 1);
+		if (ret)
+			goto out_unlock;
+	} else {
+		/*
+		 * The PHY context is shared with other MACs. Need to remove the
+		 * P2P Device from the binding, allocate an new PHY context and
+		 * create a new binding
+		 */
+		phy_ctxt = iwl_mvm_get_free_phy_ctxt(mvm);
+		if (!phy_ctxt) {
+			ret = -ENOSPC;
+			goto out_unlock;
+		}
+
+		ret = iwl_mvm_phy_ctxt_changed(mvm, phy_ctxt, &chandef,
+					       1, 1);
+		if (ret) {
+			IWL_ERR(mvm, "Failed to change PHY context\n");
+			goto out_unlock;
+		}
+
+		/* Unbind the P2P_DEVICE from the current PHY context */
+		ret = iwl_mvm_binding_remove_vif(mvm, vif);
+		if (WARN(ret, "Failed unbinding P2P_DEVICE\n"))
+			goto out_unlock;
+
+		iwl_mvm_phy_ctxt_unref(mvm, mvmvif->phy_ctxt);
+
+		/* Bind the P2P_DEVICE to the new allocated PHY context */
+		mvmvif->phy_ctxt = phy_ctxt;
+
+		ret = iwl_mvm_binding_add_vif(mvm, vif);
+		if (WARN(ret, "Failed binding P2P_DEVICE\n"))
+			goto out_unlock;
+
+		iwl_mvm_phy_ctxt_ref(mvm, mvmvif->phy_ctxt);
+	}
+
+schedule_time_event:
 	/* Schedule the time events */
 	ret = iwl_mvm_start_p2p_roc(mvm, vif, duration, type);
 
+out_unlock:
 	mutex_unlock(&mvm->mutex);
 	IWL_DEBUG_MAC80211(mvm, "leave\n");
-
 	return ret;
 }
 
@@ -1285,6 +1362,14 @@ static void iwl_mvm_change_chanctx(struct ieee80211_hw *hw,
 	u16 *phy_ctxt_id = (u16 *)ctx->drv_priv;
 	struct iwl_mvm_phy_ctxt *phy_ctxt = &mvm->phy_ctxts[*phy_ctxt_id];
 
+	if (WARN_ONCE((phy_ctxt->ref > 1) &&
+		      (changed & ~(IEEE80211_CHANCTX_CHANGE_WIDTH |
+				   IEEE80211_CHANCTX_CHANGE_RX_CHAINS |
+				   IEEE80211_CHANCTX_CHANGE_RADAR)),
+		      "Cannot change PHY. Ref=%d, changed=0x%X\n",
+		      phy_ctxt->ref, changed))
+		return;
+
 	mutex_lock(&mvm->mutex);
 	iwl_mvm_phy_ctxt_changed(mvm, phy_ctxt, &ctx->def,
 				 ctx->rx_chains_static,