iwlwifi: mvm: flush all used TX queues before suspending

There is a potential race condition when entering suspend with d0i3 in
PCIe.  If there is a frame queued just before we suspend, it won't
complete and we will never clear the queue stuck timer.  To solve
this, call TX_PATH_FLUSH to flush all queues (except the command
queue) as part of the d0i3 entry process.  Add a new function that
returns all the flushable queues.
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

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

@@ -1380,6 +1380,15 @@ void iwl_mvm_disable_txq(struct iwl_mvm *mvm, int queue, int mac80211_queue,
 			 u8 tid, u8 flags);
 int iwl_mvm_find_free_queue(struct iwl_mvm *mvm, u8 minq, u8 maxq);
 
+/* Return a bitmask with all the hw supported queues, except for the
+ * command queue, which can't be flushed.
+ */
+static inline u32 iwl_mvm_flushable_queues(struct iwl_mvm *mvm)
+{
+	return ((BIT(mvm->cfg->base_params->num_of_queues) - 1) &
+		~BIT(IWL_MVM_CMD_QUEUE));
+}
+
 static inline
 void iwl_mvm_enable_ac_txq(struct iwl_mvm *mvm, int queue, int mac80211_queue,
 			   u8 fifo, u16 ssn, unsigned int wdg_timeout)

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

@@ -1203,6 +1203,11 @@ int iwl_mvm_enter_d0i3(struct iwl_op_mode *op_mode)
 	/* make sure we have no running tx while configuring the seqno */
 	synchronize_net();
 
+	/* Flush the hw queues, in case something got queued during entry */
+	ret = iwl_mvm_flush_tx_path(mvm, iwl_mvm_flushable_queues(mvm), flags);
+	if (ret)
+		return ret;
+
 	/* configure wowlan configuration only if needed */
 	if (mvm->d0i3_ap_sta_id != IWL_MVM_STATION_COUNT) {
 		iwl_mvm_set_wowlan_data(mvm, &wowlan_config_cmd,