From f98ad635c097c29339b7a7d6947173000485893d Mon Sep 17 00:00:00 2001
From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Date: Tue, 13 Mar 2018 14:12:40 +0200
Subject: [PATCH] iwlwifi: pcie: don't access periphery registers when not available
Git-commit: f98ad635c097c29339b7a7d6947173000485893d
Patch-mainline: v4.19-rc1
References: bsc#1051510

The periphery can't be accessed before we set the
INIT_DONE bit which initializes the device.

A previous patch added a reconfiguration of the MSI-X
tables upon resume, but at that point in the flow,
INIT_DONE wasn't set. Since the reconfiguration of the
MSI-X tables require periphery access, it failed.

The difference between WoWLAN and without WoWLAN is that
in WoWLAN, iwl_trans_pcie_d3_suspend clears the INIT_DONE
without clearing the STATUS_DEVICE_ENABLED bit in the
software status. Because of that, the resume code thinks
that the device is enabled, but the INIT_DONE bit has been
cleared.

To fix this, don't reconfigure the MSI-X tables in case
WoWLAN is enabled. It will be done in
iwl_trans_pcie_d3_resume anyway.

Fixes: 52848a79b9d2 ("iwlwifi: pcie: reconfigure MSI-X HW on resume")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/wireless/intel/iwlwifi/pcie/drv.c   |    4 ++++
 drivers/net/wireless/intel/iwlwifi/pcie/trans.c |   24 ++++++++++++------------
 2 files changed, 16 insertions(+), 12 deletions(-)

--- a/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
@@ -990,6 +990,10 @@ static int iwl_pci_resume(struct device
 	 * WoWLAN is enabled - the NIC may be alive.
 	 */
 
+	/* In WOWLAN, let iwl_trans_pcie_d3_resume do the rest of the work */
+	if (test_bit(STATUS_DEVICE_ENABLED, &trans->status))
+		return 0;
+
 	/* reconfigure the MSI-X mapping to get the correct IRQ for rfkill */
 	iwl_pcie_conf_msix_hw(trans_pcie);
 
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -1538,18 +1538,6 @@ static int iwl_trans_pcie_d3_resume(stru
 
 	iwl_pcie_enable_rx_wake(trans, true);
 
-	/*
-	 * Reconfigure IVAR table in case of MSIX or reset ict table in
-	 * MSI mode since HW reset erased it.
-	 * Also enables interrupts - none will happen as
-	 * the device doesn't know we're waking it up, only when
-	 * the opmode actually tells it after this call.
-	 */
-	iwl_pcie_conf_msix_hw(trans_pcie);
-	if (!trans_pcie->msix_enabled)
-		iwl_pcie_reset_ict(trans);
-	iwl_enable_interrupts(trans);
-
 	iwl_set_bit(trans, CSR_GP_CNTRL,
 		    BIT(trans->cfg->csr->flag_mac_access_req));
 	iwl_set_bit(trans, CSR_GP_CNTRL,
@@ -1567,6 +1555,18 @@ static int iwl_trans_pcie_d3_resume(stru
 		return ret;
 	}
 
+	/*
+	 * Reconfigure IVAR table in case of MSIX or reset ict table in
+	 * MSI mode since HW reset erased it.
+	 * Also enables interrupts - none will happen as
+	 * the device doesn't know we're waking it up, only when
+	 * the opmode actually tells it after this call.
+	 */
+	iwl_pcie_conf_msix_hw(trans_pcie);
+	if (!trans_pcie->msix_enabled)
+		iwl_pcie_reset_ict(trans);
+	iwl_enable_interrupts(trans);
+
 	iwl_pcie_set_pwr(trans, false);
 
 	if (!reset) {