net/mlx5: Use RMW accessors for changing LNKCTL

[ Upstream commit 30de872537bda526664d7a20b646adfb3e7ce6e6 ]

Don't assume that only the driver would be accessing LNKCTL of the upstream
bridge. ASPM policy changes can trigger write to LNKCTL outside of driver's
control.

Use RMW capability accessors which do proper locking to avoid losing
concurrent updates to the register value.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Fixes: eabe8e5e88f5 ("net/mlx5: Handle sync reset now event")
Link: https://lore.kernel.org/r/20230717120503.15276-8-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
index 50022e7565f14303937672f33332677e359dde14..f202150a5093c6899a4cb7a1d7c0adf04b1d7e68 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
@@ -332,16 +332,11 @@ static int mlx5_pci_link_toggle(struct mlx5_core_dev *dev)
                pci_cfg_access_lock(sdev);
        }
        /* PCI link toggle */
-       err = pci_read_config_word(bridge, cap + PCI_EXP_LNKCTL, &reg16);
-       if (err)
-               return err;
-       reg16 |= PCI_EXP_LNKCTL_LD;
-       err = pci_write_config_word(bridge, cap + PCI_EXP_LNKCTL, reg16);
+       err = pcie_capability_set_word(bridge, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_LD);
        if (err)
                return err;
        msleep(500);
-       reg16 &= ~PCI_EXP_LNKCTL_LD;
-       err = pci_write_config_word(bridge, cap + PCI_EXP_LNKCTL, reg16);
+       err = pcie_capability_clear_word(bridge, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_LD);
        if (err)
                return err;