linux-kernel - [PATCH AUTOSEL 4.18 034/131] iwlwifi: pcie: don't access periphery registers when not available

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Message-ID: <20180902064601.183036-34-alexander.levin@microsoft.com>
Date:   Sun, 2 Sep 2018 13:03:40 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
        Luca Coelho <luciano.coelho@...el.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.18 034/131] iwlwifi: pcie: don't access periphery
 registers when not available

From: Emmanuel Grumbach <emmanuel.grumbach@...el.com>

[ Upstream commit f98ad635c097c29339b7a7d6947173000485893d ]

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@...el.com>
Signed-off-by: Luca Coelho <luciano.coelho@...el.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/net/wireless/intel/iwlwifi/pcie/drv.c |  4 ++++
 .../net/wireless/intel/iwlwifi/pcie/trans.c   | 24 +++++++++----------
 2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/drv.c b/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
index 8520523b91b4..d8d8443c1c93 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
@@ -1003,6 +1003,10 @@ static int iwl_pci_resume(struct device *device)
 	if (!trans->op_mode)
 		return 0;
 
+	/* 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);
 
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
index 7229991ae70d..a2a98087eb41 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -1539,18 +1539,6 @@ static int iwl_trans_pcie_d3_resume(struct iwl_trans *trans,
 
 	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,
@@ -1568,6 +1556,18 @@ static int iwl_trans_pcie_d3_resume(struct iwl_trans *trans,
 		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) {
-- 
2.17.1