iwlwifi: fix send hcmd timeout recovery flow

Both iwl_trans_fw_error and iwl_force_nmi initiate async recovery flow.
Calling them both is redundant and causing a race.

Solve this by removing the call to iwl_trans_fw_error.
Signed-off-by: Shahar S Matityahu <shahar.s.matityahu@intel.com>
Fixes: cfadc3ff ("iwlwifi: pcie: stop the firmware when we restart it")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

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

@@ -688,6 +688,9 @@ enum iwl_plat_pm_mode {
  */
 #define IWL_TRANS_IDLE_TIMEOUT 2000
 
+/* Max time to wait for nmi interrupt */
+#define IWL_TRANS_NMI_TIMEOUT (HZ / 4)
+
 /**
  * struct iwl_dram_data
  * @physical: page phy pointer

drivers/net/wireless/intel/iwlwifi/pcie/internal.h

@@ -1036,6 +1036,7 @@ static inline bool iwl_pcie_dbg_on(struct iwl_trans *trans)
 
 void iwl_trans_pcie_rf_kill(struct iwl_trans *trans, bool state);
 void iwl_trans_pcie_dump_regs(struct iwl_trans *trans);
+void iwl_trans_sync_nmi(struct iwl_trans *trans);
 
 #ifdef CONFIG_IWLWIFI_DEBUGFS
 int iwl_trans_pcie_dbgfs_register(struct iwl_trans *trans);

drivers/net/wireless/intel/iwlwifi/pcie/trans.c

@@ -3650,3 +3650,28 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
 	iwl_trans_free(trans);
 	return ERR_PTR(ret);
 }
+
+void iwl_trans_sync_nmi(struct iwl_trans *trans)
+{
+	unsigned long timeout = jiffies + IWL_TRANS_NMI_TIMEOUT;
+
+	iwl_disable_interrupts(trans);
+	iwl_force_nmi(trans);
+	while (time_after(timeout, jiffies)) {
+		u32 inta_hw = iwl_read32(trans,
+					 CSR_MSIX_HW_INT_CAUSES_AD);
+
+		/* Error detected by uCode */
+		if (inta_hw & MSIX_HW_INT_CAUSES_REG_SW_ERR) {
+			/* Clear causes register */
+			iwl_write32(trans, CSR_MSIX_HW_INT_CAUSES_AD,
+				    inta_hw &
+				    MSIX_HW_INT_CAUSES_REG_SW_ERR);
+			break;
+		}
+
+		mdelay(1);
+	}
+	iwl_enable_interrupts(trans);
+	iwl_trans_fw_error(trans);
+}

drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c

@@ -6,7 +6,7 @@
  * GPL LICENSE SUMMARY
  *
  * Copyright(c) 2017 Intel Deutschland GmbH
- * Copyright(c) 2018        Intel Corporation
+ * Copyright(c) 2018 - 2019 Intel Corporation
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
@@ -20,7 +20,7 @@
  * BSD LICENSE
  *
  * Copyright(c) 2017 Intel Deutschland GmbH
- * Copyright(c) 2018        Intel Corporation
+ * Copyright(c) 2018 - 2019 Intel Corporation
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -965,9 +965,7 @@ static int iwl_pcie_gen2_send_hcmd_sync(struct iwl_trans *trans,
 			       cmd_str);
 		ret = -ETIMEDOUT;
 
-		iwl_force_nmi(trans);
-		iwl_trans_fw_error(trans);
-
+		iwl_trans_sync_nmi(trans);
 		goto cancel;
 	}
 

drivers/net/wireless/intel/iwlwifi/pcie/tx.c

@@ -8,7 +8,7 @@
  * Copyright(c) 2003 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
  * Copyright(c) 2016 - 2017 Intel Deutschland GmbH
- * Copyright(c) 2018 Intel Corporation
+ * Copyright(c) 2018 - 2019 Intel Corporation
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of version 2 of the GNU General Public License as
@@ -31,7 +31,7 @@
  * Copyright(c) 2003 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
  * Copyright(c) 2016 - 2017 Intel Deutschland GmbH
- * Copyright(c) 2018 Intel Corporation
+ * Copyright(c) 2018 - 2019 Intel Corporation
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -1942,9 +1942,7 @@ static int iwl_pcie_send_hcmd_sync(struct iwl_trans *trans,
 			       iwl_get_cmd_string(trans, cmd->id));
 		ret = -ETIMEDOUT;
 
-		iwl_force_nmi(trans);
-		iwl_trans_fw_error(trans);
-
+		iwl_trans_sync_nmi(trans);
 		goto cancel;
 	}