mlxsw: pci: Implement PCI reset handlers

Implement reset_prepare() and reset_done() handlers that are invoked by
the PCI core before and after issuing a PCI reset, respectively.

Specifically, implement reset_prepare() by calling
mlxsw_core_bus_device_unregister() and reset_done() by calling
mlxsw_core_bus_device_register(). This is the same implementation as the
reload_{down,up}() devlink operations with the following differences:

1. The devlink instance is unregistered and then registered again after
   the reset.

2. A reset via the device's command interface (using MRSR register) is
   not issued during reset_done() as PCI core already issued a PCI
   reset.

Tested:

 # for i in $(seq 1 10); do echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/reset; done

Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci.c b/drivers/net/ethernet/mellanox/mlxsw/pci.c
index 726ed707e27b9140f8f503db4902625bf91b9403..5b1f2483a3ccf3f009339d672e92c0aa602ff1d1 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/pci.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/pci.c
@@ -130,6 +130,7 @@ struct mlxsw_pci {
        const struct pci_device_id *id;
        enum mlxsw_pci_cqe_v max_cqe_ver; /* Maximal supported CQE version */
        u8 num_sdq_cqs; /* Number of CQs used for SDQs */
+       bool skip_reset;
 };
 
 static void mlxsw_pci_queue_tasklet_schedule(struct mlxsw_pci_queue *q)
@@ -1527,6 +1528,10 @@ mlxsw_pci_reset(struct mlxsw_pci *mlxsw_pci, const struct pci_device_id *id)
                return err;
        }
 
+       /* PCI core already issued a PCI reset, do not issue another reset. */
+       if (mlxsw_pci->skip_reset)
+               return 0;
+
        mlxsw_reg_mcam_pack(mcam_pl,
                            MLXSW_REG_MCAM_FEATURE_GROUP_ENHANCED_FEATURES);
        err = mlxsw_reg_query(mlxsw_pci->core, MLXSW_REG(mcam), mcam_pl);
@@ -2107,11 +2112,34 @@ static void mlxsw_pci_remove(struct pci_dev *pdev)
        kfree(mlxsw_pci);
 }
 
+static void mlxsw_pci_reset_prepare(struct pci_dev *pdev)
+{
+       struct mlxsw_pci *mlxsw_pci = pci_get_drvdata(pdev);
+
+       mlxsw_core_bus_device_unregister(mlxsw_pci->core, false);
+}
+
+static void mlxsw_pci_reset_done(struct pci_dev *pdev)
+{
+       struct mlxsw_pci *mlxsw_pci = pci_get_drvdata(pdev);
+
+       mlxsw_pci->skip_reset = true;
+       mlxsw_core_bus_device_register(&mlxsw_pci->bus_info, &mlxsw_pci_bus,
+                                      mlxsw_pci, false, NULL, NULL);
+       mlxsw_pci->skip_reset = false;
+}
+
+static const struct pci_error_handlers mlxsw_pci_err_handler = {
+       .reset_prepare = mlxsw_pci_reset_prepare,
+       .reset_done = mlxsw_pci_reset_done,
+};
+
 int mlxsw_pci_driver_register(struct pci_driver *pci_driver)
 {
        pci_driver->probe = mlxsw_pci_probe;
        pci_driver->remove = mlxsw_pci_remove;
        pci_driver->shutdown = mlxsw_pci_remove;
+       pci_driver->err_handler = &mlxsw_pci_err_handler;
        return pci_register_driver(pci_driver);
 }
 EXPORT_SYMBOL(mlxsw_pci_driver_register);