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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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