RE: [PATCH 2/2] PCI: imx6: Add imx_pcie_perst_found() to inspect the parsed result

[Hongxing Zhu]

> -----Original Message-----
> From: Sherry Sun (OSS) <sherry.sun@xxxxxxxxxxx>
> Sent: Friday, May 22, 2026 11:44 AM
> To: Hongxing Zhu <hongxing.zhu@xxxxxxx>; l.stach@xxxxxxxxxxxxxx; Frank Li
> <frank.li@xxxxxxx>; bhelgaas@xxxxxxxxxx; lpieralisi@xxxxxxxxxx;
> kwilczynski@xxxxxxxxxx; mani@xxxxxxxxxx; robh@xxxxxxxxxx;
> s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx;
> will@xxxxxxxxxx
> Cc: imx@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Sherry Sun
> <sherry.sun@xxxxxxx>
> Subject: [PATCH 2/2] PCI: imx6: Add imx_pcie_perst_found() to inspect the
> parsed result
> 
> From: Sherry Sun <sherry.sun@xxxxxxx>
> 
> Since pci_host_common_parse_port() doesn't return failure for "property not
> found"(-ENODEV), the caller should inspect the parsed result and decide whether
One space should be placed before (-ENODEV).

> to fall back to the legacy binding.
> Add imx_pcie_perst_found() to inspect the parsed result.
> 
> Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
Reviewed-by: Richard Zhu <hongxing.zhu@xxxxxxx>

Best Regards
Richard Zhu

> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 25 +++++++++++++++++--------
>  1 file changed, 17 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> b/drivers/pci/controller/dwc/pci-imx6.c
> index b137551871fc..34756f28fcc6 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1287,6 +1287,18 @@ static void imx_pcie_assert_perst(struct imx_pcie
> *imx_pcie, bool assert)
>  	}
>  }
> 
> +static bool imx_pcie_perst_found(struct pci_host_bridge *bridge) {
> +	struct pci_host_port *port;
> +
> +	list_for_each_entry(port, &bridge->ports, list) {
> +		if (!list_empty(&port->perst))
> +			return true;
> +	}
> +
> +	return false;
> +}
> +
>  static int imx_pcie_host_init(struct dw_pcie_rp *pp)  {
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp); @@ -1299,15 +1311,12
> @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
>  		/* Parse Root Port nodes if present */
>  		ret = pci_host_common_parse_ports(dev, bridge);
>  		if (ret) {
> -			if (ret != -ENODEV) {
> -				dev_err(dev, "Failed to parse Root Port
> nodes: %d\n", ret);
> -				return ret;
> -			}
> +			dev_err(dev, "Failed to parse Root Port nodes: %d\n",
> ret);
> +			return ret;
> +		}
> 
> -			/*
> -			 * Fall back to legacy binding for DT backwards
> -			 * compatibility
> -			 */
> +		/* Fallback to legacy binding for DT backwards compatibility. */
> +		if (!imx_pcie_perst_found(bridge)) {
>  			ret = imx_pcie_parse_legacy_binding(imx_pcie);
>  			if (ret)
>  				return ret;
> --
> 2.37.1