[v4,16/18] PCI: dwc-plat: Simplify the probe method return value handling

Commit Message

Serge Semin June 10, 2022, 8:25 a.m. UTC

The whole switch-case-logic implemented in the DWC PCIe RC/EP probe
procedure doesn't seem well thought through. First of all the ret variable
is unused in the EP-case and is only partly involved in the RC-case of the
switch-case statement, which unnecessary complicates the code. Secondly
the probe method will return zero if an unknown mode is detected. That is
improbable situation since the OF-device data is initialized only with
valid modes, but such code is still wrong at least from maintainability
point of view. So let's convert the switch-case part of the probe function
to being more coherent. We suggest to use the local ret variable to
preserve the status of the case-clauses and return its value from the
probe procedure after the work is done.

Signed-off-by: Serge Semin <[e-mail]>
Reviewed-by: Manivannan Sadhasivam <[e-mail]>
Tested-by: Manivannan Sadhasivam <[e-mail]>
---
 drivers/pci/controller/dwc/pcie-designware-plat.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Comments

Rob Herring (Arm) June 13, 2022, 8:44 p.m. UTC | #1

On Fri, Jun 10, 2022 at 11:25:32AM +0300, Serge Semin wrote:
> The whole switch-case-logic implemented in the DWC PCIe RC/EP probe
> procedure doesn't seem well thought through. First of all the ret variable
> is unused in the EP-case and is only partly involved in the RC-case of the
> switch-case statement, which unnecessary complicates the code. Secondly
> the probe method will return zero if an unknown mode is detected. That is
> improbable situation since the OF-device data is initialized only with
> valid modes, but such code is still wrong at least from maintainability
> point of view. So let's convert the switch-case part of the probe function
> to being more coherent. We suggest to use the local ret variable to
> preserve the status of the case-clauses and return its value from the
> probe procedure after the work is done.
> 
> Signed-off-by: Serge Semin <[e-mail]>
> Reviewed-by: Manivannan Sadhasivam <[e-mail]>
> Tested-by: Manivannan Sadhasivam <[e-mail]>
> ---
>  drivers/pci/controller/dwc/pcie-designware-plat.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)

Reviewed-by: Rob Herring <[e-mail]>

Patch

diff --git a/drivers/pci/controller/dwc/pcie-designware-plat.c b/drivers/pci/controller/dwc/pcie-designware-plat.c
index 97de6ad7f9db..c6871bebf3fe 100644
--- a/drivers/pci/controller/dwc/pcie-designware-plat.c
+++ b/drivers/pci/controller/dwc/pcie-designware-plat.c
@@ -143,20 +143,21 @@  static int dw_plat_pcie_probe(struct platform_device *pdev)
 			return -ENODEV;
 
 		ret = dw_plat_add_pcie_port(dw_plat_pcie, pdev);
-		if (ret < 0)
-			return ret;
 		break;
 	case DW_PCIE_EP_TYPE:
 		if (!IS_ENABLED(CONFIG_PCIE_DW_PLAT_EP))
 			return -ENODEV;
 
 		pci->ep.ops = &pcie_ep_ops;
-		return dw_pcie_ep_init(&pci->ep);
+		ret = dw_pcie_ep_init(&pci->ep);
+		break;
 	default:
 		dev_err(dev, "INVALID device type %d\n", dw_plat_pcie->mode);
+		ret = -EINVAL;
+		break;
 	}
 
-	return 0;
+	return ret;
 }
 
 static const struct dw_plat_pcie_of_data dw_plat_pcie_rc_of_data = {