Re: [PATCH v3 3/4] PCI: dwc: Reduce DT reads by allocating host bridge via DWC glue driver

Manivannan Sadhasivam
2025-01-24T06:18:42Z

On Tue, Jan 21, 2025 at 02:32:21PM +0530, Krishna Chaitanya Chundru wrote:
> Allow DWC glue drivers to allocate the host bridge, avoiding redundant
> device tree reads primarily in dw_pcie_ecam_supported().
>

I don't understand what you mean by 'redundant device tree reads'. Please
explain.

- Mani

> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
> ---
> drivers/pci/controller/dwc/pcie-designware-host.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 3888f9fe5af1..0acf9db44f2c 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -484,8 +484,8 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
> struct device *dev = pci->dev;
> struct device_node *np = dev->of_node;
> struct platform_device *pdev = to_platform_device(dev);
> + struct pci_host_bridge *bridge = pp->bridge;
> struct resource_entry *win;
> - struct pci_host_bridge *bridge;
> struct resource *res;
> int ret;
>
> @@ -497,11 +497,12 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
> return -ENODEV;
> }
>
> - bridge = devm_pci_alloc_host_bridge(dev, 0);
> - if (!bridge)
> - return -ENOMEM;
> -
> - pp->bridge = bridge;
> + if (!pp->bridge) {
> + bridge = devm_pci_alloc_host_bridge(dev, 0);
> + if (!bridge)
> + return -ENOMEM;
> + pp->bridge = bridge;
> + }
>
> pp->cfg0_size = resource_size(res);
> pp->cfg0_base = res->start;
>
> --
> 2.34.1
>

--
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