mlxsw: spectrum: Reset FW after flash

Recent FW fixes a bug and allows to load newly flashed FW image after
reset. So make sure the reset happens after flash. Indicate the need
down to PCI layer by -EAGAIN.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core.h

@@ -362,6 +362,7 @@ struct mlxsw_fw_rev {
 	u16 major;
 	u16 minor;
 	u16 subminor;
+	u16 can_reset_minor;
 };
 
 struct mlxsw_bus_info {

drivers/net/ethernet/mellanox/mlxsw/pci.c

@@ -1750,6 +1750,7 @@ static int mlxsw_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	const char *driver_name = pdev->driver->name;
 	struct mlxsw_pci *mlxsw_pci;
+	bool called_again = false;
 	int err;
 
 	mlxsw_pci = kzalloc(sizeof(*mlxsw_pci), GFP_KERNEL);
@@ -1806,10 +1807,18 @@ static int mlxsw_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	mlxsw_pci->bus_info.dev = &pdev->dev;
 	mlxsw_pci->id = id;
 
+again:
 	err = mlxsw_core_bus_device_register(&mlxsw_pci->bus_info,
 					     &mlxsw_pci_bus, mlxsw_pci, false,
 					     NULL);
-	if (err) {
+	/* -EAGAIN is returned in case the FW was updated. FW needs
+	 * a reset, so lets try to call mlxsw_core_bus_device_register()
+	 * again.
+	 */
+	if (err == -EAGAIN && !called_again) {
+		called_again = true;
+		goto again;
+	} else if (err) {
 		dev_err(&pdev->dev, "cannot register bus device\n");
 		goto err_bus_device_register;
 	}

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -79,11 +79,13 @@
 #define MLXSW_SP1_FWREV_MAJOR 13
 #define MLXSW_SP1_FWREV_MINOR 1702
 #define MLXSW_SP1_FWREV_SUBMINOR 6
+#define MLXSW_SP1_FWREV_CAN_RESET_MINOR 1702
 
 static const struct mlxsw_fw_rev mlxsw_sp1_fw_rev = {
 	.major = MLXSW_SP1_FWREV_MAJOR,
 	.minor = MLXSW_SP1_FWREV_MINOR,
 	.subminor = MLXSW_SP1_FWREV_SUBMINOR,
+	.can_reset_minor = MLXSW_SP1_FWREV_CAN_RESET_MINOR,
 };
 
 #define MLXSW_SP1_FW_FILENAME \
@@ -380,7 +382,16 @@ static int mlxsw_sp_fw_rev_validate(struct mlxsw_sp *mlxsw_sp)
 
 	err = mlxsw_sp_firmware_flash(mlxsw_sp, firmware);
 	release_firmware(firmware);
-	return err;
+	if (err)
+		dev_err(mlxsw_sp->bus_info->dev, "Could not upgrade firmware\n");
+
+	/* On FW flash success, tell the caller FW reset is needed
+	 * if current FW supports it.
+	 */
+	if (rev->minor >= req_rev->can_reset_minor)
+		return err ? err : -EAGAIN;
+	else
+		return 0;
 }
 
 int mlxsw_sp_flow_counter_get(struct mlxsw_sp *mlxsw_sp,
@@ -3734,10 +3745,8 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 	mlxsw_sp->bus_info = mlxsw_bus_info;
 
 	err = mlxsw_sp_fw_rev_validate(mlxsw_sp);
-	if (err) {
-		dev_err(mlxsw_sp->bus_info->dev, "Could not upgrade firmware\n");
+	if (err)
 		return err;
-	}
 
 	err = mlxsw_sp_base_mac_get(mlxsw_sp);
 	if (err) {