Re: [PATCH v7 2/5] PCI: dwc: Add helper to find the Vendor Specific Extended Capability (VSEC)

[Fan Ni <nifan.cxl@gmail.com>]

On Fri, Feb 21, 2025 at 06:45:45PM +0530, Shradha Todi wrote:
> dw_pcie_find_vsec_capability() is used by upcoming DWC APIs to find the
How are about "Add dw_pcie_find_ext_capability(), which will be used by
..."

Other than that,


Reviewed-by: Fan Ni <fan.ni@samsung.com>

> VSEC capabilities like PTM, RAS etc.
> 
> Co-developed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Signed-off-by: Shradha Todi <shradha.t@samsung.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware.c | 40 ++++++++++++++++++++
>  1 file changed, 40 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> index 145e7f579072..a7c0671c6715 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.c
> +++ b/drivers/pci/controller/dwc/pcie-designware.c
> @@ -16,6 +16,7 @@
>  #include <linux/gpio/consumer.h>
>  #include <linux/ioport.h>
>  #include <linux/of.h>
> +#include <linux/pcie-dwc.h>
>  #include <linux/platform_device.h>
>  #include <linux/sizes.h>
>  #include <linux/types.h>
> @@ -283,6 +284,45 @@ u16 dw_pcie_find_ext_capability(struct dw_pcie *pci, u8 cap)
>  }
>  EXPORT_SYMBOL_GPL(dw_pcie_find_ext_capability);
>  
> +static u16 __dw_pcie_find_vsec_capability(struct dw_pcie *pci, u16 vendor_id,
> +					  u16 vsec_id)
> +{
> +	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_id)
> +			return vsec;
> +	}
> +
> +	return 0;
> +}
> +
> +static u16 dw_pcie_find_vsec_capability(struct dw_pcie *pci,
> +					const struct dwc_pcie_vsec_id *vsec_ids)
> +{
> +	const struct dwc_pcie_vsec_id *vid;
> +	u16 vsec;
> +	u32 header;
> +
> +	for (vid = vsec_ids; vid->vendor_id; vid++) {
> +		vsec = __dw_pcie_find_vsec_capability(pci, vid->vendor_id,
> +						      vid->vsec_id);
> +		if (vsec) {
> +			header = dw_pcie_readl_dbi(pci, vsec + PCI_VNDR_HEADER);
> +			if (PCI_VNDR_HEADER_REV(header) == vid->vsec_rev)
> +				return vsec;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  int dw_pcie_read(void __iomem *addr, int size, u32 *val)
>  {
>  	if (!IS_ALIGNED((uintptr_t)addr, size)) {
> -- 
> 2.17.1
>