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Subject[PATCH AUTOSEL 4.18 034/131] iwlwifi: pcie: don't access periphery registers when not available
Date
From: Emmanuel Grumbach <emmanuel.grumbach@intel.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@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.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
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