Re: [PATCH V1 2/2] PCI: designware-ep: Disable PTM capabilities for EP mode

From: Han Jingoo
Date: Fri Sep 23 2022 - 17:40:53 EST


On Mon, Sep 19, 2022, Vidya Sagar <vidyas@xxxxxxxxxx> wrote:
>
> Dual mode DesignWare PCIe IP has PTM capability enabled (if supported) even
> in the EP mode. The PCIe compliance for the EP mode expects PTM
> capabilities (ROOT_CAPABLE, RES_CAPABLE, CLK_GRAN) be disabled.
> Hence disable PTM for the EP mode.
>
> Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> ---
> .../pci/controller/dwc/pcie-designware-ep.c | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 7e9529ae3824..dc3057b18f36 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -646,7 +646,7 @@ int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
> struct dw_pcie_ep_func *ep_func;
> struct device *dev = pci->dev;
> struct pci_epc *epc = ep->epc;
> - unsigned int offset;
> + unsigned int offset, ptm_cap_base;

Is there any reason to mix these 2 variables into 1 line?
If not, please add a new line for ptm_cap_base.

unsigned int offset;
unsigned int ptm_cap_base;

Also, it looks ok. When you send a new patch, just add my Acked-by.
Acked-by: Jingoo Han <jingoohan1@xxxxxxxxx>

Best regards,
Jingoo Han

> unsigned int nbars;
> u8 hdr_type;
> u8 func_no;
> @@ -698,6 +698,7 @@ int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
> }
>
> offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
> + ptm_cap_base = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_PTM);
>
> dw_pcie_dbi_ro_wr_en(pci);
>
> @@ -710,6 +711,22 @@ int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
> dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0);
> }
>
> + /*
> + * PTM responder capability can be disabled only after disabling
> + * PTM root capability.
> + */
> + if (ptm_cap_base) {
> + dw_pcie_dbi_ro_wr_en(pci);
> + reg = dw_pcie_readl_dbi(pci, ptm_cap_base + PCI_PTM_CAP);
> + reg &= ~PCI_PTM_CAP_ROOT;
> + dw_pcie_writel_dbi(pci, ptm_cap_base + PCI_PTM_CAP, reg);
> +
> + reg = dw_pcie_readl_dbi(pci, ptm_cap_base + PCI_PTM_CAP);
> + reg &= ~(PCI_PTM_CAP_RES | PCI_PTM_GRANULARITY_MASK);
> + dw_pcie_writel_dbi(pci, ptm_cap_base + PCI_PTM_CAP, reg);
> + dw_pcie_dbi_ro_wr_dis(pci);
> + }
> +
> dw_pcie_setup(pci);
> dw_pcie_dbi_ro_wr_dis(pci);
>
> --
> 2.17.1
>