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

Fan Ni
2025-03-03T17:24:48Z

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
>