iwlwifi: use sync nmi in case of init flow failure

In case of alive interrupt timeout or any failure in the init flow
the driver generates FW nmi. The driver assumes that the nmi will
generate SW interrupt. This assumption does not hold and leads to faulty
behavior in the recovery flow.

Solve this by using sync nmi, this way, even if the driver does not
receive SW interrupt, it still starts the recovery flow.

Also remove the wait queue from iwl_fwrt_stop_device since the driver is
handling the SW interrupt synchronously.
Signed-off-by: Shahar S Matityahu <shahar.s.matityahu@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/fw/dbg.c

@@ -1944,14 +1944,10 @@ int iwl_fw_dbg_error_collect(struct iwl_fw_runtime *fwrt,
 	iwl_dump_error_desc->len = 0;
 
 	ret = iwl_fw_dbg_collect_desc(fwrt, iwl_dump_error_desc, false, 0);
-	if (ret) {
+	if (ret)
 		kfree(iwl_dump_error_desc);
-	} else {
-		set_bit(STATUS_FW_WAIT_DUMP, &fwrt->trans->status);
-
-		/* trigger nmi to halt the fw */
-		iwl_force_nmi(fwrt->trans);
-	}
+	else
+		iwl_trans_sync_nmi(fwrt->trans);
 
 	return ret;
 }
@@ -2491,22 +2487,6 @@ IWL_EXPORT_SYMBOL(iwl_fw_dbg_apply_point);
 
 void iwl_fwrt_stop_device(struct iwl_fw_runtime *fwrt)
 {
-	/* if the wait event timeout elapses instead of wake up then
-	 * the driver did not receive NMI interrupt and can not assume the FW
-	 * is halted
-	 */
-	int ret = wait_event_timeout(fwrt->trans->fw_halt_waitq,
-				     !test_bit(STATUS_FW_WAIT_DUMP,
-					       &fwrt->trans->status),
-				     msecs_to_jiffies(2000));
-	if (!ret) {
-		/* failed to receive NMI interrupt, assuming the FW is stuck */
-		set_bit(STATUS_FW_ERROR, &fwrt->trans->status);
-
-		clear_bit(STATUS_FW_WAIT_DUMP, &fwrt->trans->status);
-	}
-
-	/* Assuming the op mode mutex is held at this point */
 	iwl_fw_dbg_collect_sync(fwrt);
 
 	iwl_trans_stop_device(fwrt->trans);

drivers/net/wireless/intel/iwlwifi/fw/init.c

@@ -76,7 +76,6 @@ void iwl_fw_runtime_init(struct iwl_fw_runtime *fwrt, struct iwl_trans *trans,
 	fwrt->ops_ctx = ops_ctx;
 	INIT_DELAYED_WORK(&fwrt->dump.wk, iwl_fw_error_dump_wk);
 	iwl_fwrt_dbgfs_register(fwrt, dbgfs_dir);
-	init_waitqueue_head(&fwrt->trans->fw_halt_waitq);
 }
 IWL_EXPORT_SYMBOL(iwl_fw_runtime_init);
 

drivers/net/wireless/intel/iwlwifi/iwl-trans.h

@@ -338,7 +338,6 @@ enum iwl_d3_status {
  *	are sent
  * @STATUS_TRANS_IDLE: the trans is idle - general commands are not to be sent
  * @STATUS_TRANS_DEAD: trans is dead - avoid any read/write operation
- * @STATUS_FW_WAIT_DUMP: if set, wait until cleared before collecting dump
  */
 enum iwl_trans_status {
 	STATUS_SYNC_HCMD_ACTIVE,
@@ -351,7 +350,6 @@ enum iwl_trans_status {
 	STATUS_TRANS_GOING_IDLE,
 	STATUS_TRANS_IDLE,
 	STATUS_TRANS_DEAD,
-	STATUS_FW_WAIT_DUMP,
 };
 
 static inline int
@@ -832,7 +830,6 @@ struct iwl_trans {
 	u32 lmac_error_event_table[2];
 	u32 umac_error_event_table;
 	unsigned int error_event_table_tlv_status;
-	wait_queue_head_t fw_halt_waitq;
 
 	/* pointer to trans specific struct */
 	/*Ensure that this pointer will always be aligned to sizeof pointer */
@@ -1240,10 +1237,6 @@ static inline void iwl_trans_fw_error(struct iwl_trans *trans)
 	/* prevent double restarts due to the same erroneous FW */
 	if (!test_and_set_bit(STATUS_FW_ERROR, &trans->status))
 		iwl_op_mode_nic_error(trans->op_mode);
-
-	if (test_and_clear_bit(STATUS_FW_WAIT_DUMP, &trans->status))
-		wake_up(&trans->fw_halt_waitq);
-
 }
 
 static inline void iwl_trans_sync_nmi(struct iwl_trans *trans)