iwlwifi: mvm: don't keep an mvm ref when the interface is down

There is no reason to keep a reference when the interface is down,
since we are not really doing anything.  The reference is only needed
when the mac80211 start op (or a hw restart) is running, to prevent
going into runtime or system supend in the meantime.  This will allow
us to support runtime PM when the interface is down (in another
patch).
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

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

@@ -1004,10 +1004,18 @@ int __iwl_mvm_mac_start(struct iwl_mvm *mvm)
 
 	lockdep_assert_held(&mvm->mutex);
 
-	/* Clean up some internal and mac80211 state on restart */
-	if (test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status))
+	if (test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status)) {
+		/* Clean up some internal and mac80211 state on restart */
 		iwl_mvm_restart_cleanup(mvm);
-
+	} else {
+		/* Hold the reference to prevent runtime suspend while
+		 * the start procedure runs.  It's a bit confusing
+		 * that the UCODE_DOWN reference is taken, but it just
+		 * means "UCODE is not UP yet". ( TODO: rename this
+		 * reference).
+		 */
+		iwl_mvm_ref(mvm, IWL_MVM_REF_UCODE_DOWN);
+	}
 	ret = iwl_mvm_up(mvm);
 
 	if (ret && test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status)) {
@@ -1110,14 +1118,6 @@ void __iwl_mvm_mac_stop(struct iwl_mvm *mvm)
 	 */
 	memset(&mvm->accu_radio_stats, 0, sizeof(mvm->accu_radio_stats));
 
-	/*
-	 * Disallow low power states when the FW is down by taking
-	 * the UCODE_DOWN ref. in case of ongoing hw restart the
-	 * ref is already taken, so don't take it again.
-	 */
-	if (!test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status))
-		iwl_mvm_ref(mvm, IWL_MVM_REF_UCODE_DOWN);
-
 	/* async_handlers_wk is now blocked */
 
 	/*

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

@@ -607,8 +607,8 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
 
 	memset(&mvm->rx_stats, 0, sizeof(struct mvm_statistics_rx));
 
-	/* rpm starts with a taken ref. only set the appropriate bit here. */
-	mvm->refs[IWL_MVM_REF_UCODE_DOWN] = 1;
+	/* rpm starts with a taken reference, we can release it now */
+	iwl_trans_unref(mvm->trans);
 
 	iwl_mvm_tof_init(mvm);