Re: [PATCH v6 1/4] PCI: dwc: Add support for vendor specific capability search

[Manivannan Sadhasivam]

On Fri, Feb 14, 2025 at 04:20:04PM +0530, Shradha Todi wrote:
> Add vendor specific extended configuration space capability search API
> using struct dw_pcie pointer for DW controllers.
> 
> Signed-off-by: Shradha Todi <shradha.t@xxxxxxxxxxx>

I took this patch and modified to pass the 'struct dwc_pcie_vsec_id' to the API
to simplify the callers:
https://lore.kernel.org/linux-pci/20250218-pcie-qcom-ptm-v1-2-16d7e480d73e@xxxxxxxxxx

- Mani

> ---
>  drivers/pci/controller/dwc/pcie-designware.c | 19 +++++++++++++++++++
>  drivers/pci/controller/dwc/pcie-designware.h |  1 +
>  2 files changed, 20 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> index 6d6cbc8b5b2c..3588197ba2d7 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.c
> +++ b/drivers/pci/controller/dwc/pcie-designware.c
> @@ -277,6 +277,25 @@ static u16 dw_pcie_find_next_ext_capability(struct dw_pcie *pci, u16 start,
>  	return 0;
>  }
>  
> +u16 dw_pcie_find_vsec_capability(struct dw_pcie *pci, u16 vendor_id, u16 vsec_cap)
> +{
> +	u16 vsec = 0;
> +	u32 header;
> +
> +	if (vendor_id != dw_pcie_readw_dbi(pci, PCI_VENDOR_ID))
> +		return 0;
> +
> +	while ((vsec = dw_pcie_find_next_ext_capability(pci, vsec,
> +					PCI_EXT_CAP_ID_VNDR))) {
> +		header = dw_pcie_readl_dbi(pci, vsec + PCI_VNDR_HEADER);
> +		if (PCI_VNDR_HEADER_ID(header) == vsec_cap)
> +			return vsec;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(dw_pcie_find_vsec_capability);
> +
>  u16 dw_pcie_find_ext_capability(struct dw_pcie *pci, u8 cap)
>  {
>  	return dw_pcie_find_next_ext_capability(pci, 0, cap);
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 347ab74ac35a..02e94bd9b042 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -476,6 +476,7 @@ void dw_pcie_version_detect(struct dw_pcie *pci);
>  
>  u8 dw_pcie_find_capability(struct dw_pcie *pci, u8 cap);
>  u16 dw_pcie_find_ext_capability(struct dw_pcie *pci, u8 cap);
> +u16 dw_pcie_find_vsec_capability(struct dw_pcie *pci, u16 vendor_id, u16 vsec_cap);
>  
>  int dw_pcie_read(void __iomem *addr, int size, u32 *val);
>  int dw_pcie_write(void __iomem *addr, int size, u32 val);
> -- 
> 2.17.1
> 

-- 
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