Re: [PATCH v8 2/5] PCI: dwc: Add support for ELBI resource mapping

[Manivannan Sadhasivam <mani@kernel.org>]

On Thu, Aug 28, 2025 at 01:04:23PM GMT, Krishna Chaitanya Chundru wrote:
> External Local Bus Interface(ELBI) registers are optional registers in
> DWC IPs having vendor specific registers.
> 
> Since ELBI register space is applicable for all DWC based controllers,
> move the resource get code to DWC core and make it optional.
> 

As discussed offline, this changes also warrants switching the glue drivers to
use 'dw_pci::elbi' base instead of their own. So I've ammended this commit to
include those changes also while applying (which was straightforward).

- Mani

> Suggested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware.c | 9 +++++++++
>  drivers/pci/controller/dwc/pcie-designware.h | 1 +
>  2 files changed, 10 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> index 89aad5a08928cc29870ab258d33bee9ff8f83143..4684c671a81bee468f686a83cc992433b38af59d 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.c
> +++ b/drivers/pci/controller/dwc/pcie-designware.c
> @@ -167,6 +167,15 @@ int dw_pcie_get_resources(struct dw_pcie *pci)
>  		}
>  	}
>  
> +	if (!pci->elbi_base) {
> +		res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "elbi");
> +		if (res) {
> +			pci->elbi_base = devm_ioremap_resource(pci->dev, res);
> +			if (IS_ERR(pci->elbi_base))
> +				return PTR_ERR(pci->elbi_base);
> +		}
> +	}
> +
>  	/* LLDD is supposed to manually switch the clocks and resets state */
>  	if (dw_pcie_cap_is(pci, REQ_RES)) {
>  		ret = dw_pcie_get_clocks(pci);
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 00f52d472dcdd794013a865ad6c4c7cc251edb48..ceb022506c3191cd8fe580411526e20cc3758fed 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -492,6 +492,7 @@ struct dw_pcie {
>  	resource_size_t		dbi_phys_addr;
>  	void __iomem		*dbi_base2;
>  	void __iomem		*atu_base;
> +	void __iomem		*elbi_base;
>  	resource_size_t		atu_phys_addr;
>  	size_t			atu_size;
>  	resource_size_t		parent_bus_offset;
> 
> -- 
> 2.34.1
> 

-- 
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