On Wed, Oct 25, 2023 at 06:30:29PM +0530, Manivannan Sadhasivam wrote:
> DWC core driver exposes the write_dbi2() callback for writing to the DBI2
> registers in a vendor specific way. On the Qcom EP plaforms, DBI_CS2 bit in
> the ELBI region needs to be asserted before writing to any DBI2 registers
> and deasserted once done. So let's implement the callback for the Qcom PCIe
> EP driver so that the DBI2 writes are handled properly in the hardware.
>
> Without this callback, DBI2 register writes like BAR size won't go through
> and as a result, the default BAR size is set for all BARs.
>
> Cc: stable@xxxxxxxxxxxxxxx # 5.16+
> Fixes: f55fee56a631 ("PCI: qcom-ep: Add Qualcomm PCIe Endpoint controller driver")
> Suggested-by: Serge Semin <fancer.lancer@xxxxxxxxx>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Reviewed-by: Serge Semin <fancer.lancer@xxxxxxxxx>
+1 tiny note below
> ---
> drivers/pci/controller/dwc/pcie-qcom-ep.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> index 32c8d9e37876..7da0599f70e7 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> @@ -124,6 +124,7 @@
>
> /* ELBI registers */
> #define ELBI_SYS_STTS 0x08
> +#define ELBI_CS2_ENABLE 0xa4
>
> /* DBI registers */
> #define DBI_CON_STATUS 0x44
> @@ -262,6 +263,21 @@ static void qcom_pcie_dw_stop_link(struct dw_pcie *pci)
> disable_irq(pcie_ep->perst_irq);
> }
>
> +static void qcom_pcie_write_dbi2(struct dw_pcie *pci, void __iomem *base,
Just a general observation. I am not sure whether it's a local
convention or not, but it looks like the rest of the Qcom dw_pcie_ops
callbacks have the "qcom_pcie_dw_" prefix.
-Serge(y)
> + u32 reg, size_t size, u32 val)
> +{
> + struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
> + int ret;
> +
> + writel(1, pcie_ep->elbi + ELBI_CS2_ENABLE);
> +
> + ret = dw_pcie_write(pci->dbi_base2 + reg, size, val);
> + if (ret)
> + dev_err(pci->dev, "Failed to write DBI2 register (0x%x): %d\n", reg, ret);
> +
> + writel(0, pcie_ep->elbi + ELBI_CS2_ENABLE);
> +}
> +
> static void qcom_pcie_ep_icc_update(struct qcom_pcie_ep *pcie_ep)
> {
> struct dw_pcie *pci = &pcie_ep->pci;
> @@ -500,6 +516,7 @@ static const struct dw_pcie_ops pci_ops = {
> .link_up = qcom_pcie_dw_link_up,
> .start_link = qcom_pcie_dw_start_link,
> .stop_link = qcom_pcie_dw_stop_link,
> + .write_dbi2 = qcom_pcie_write_dbi2,
> };
>
> static int qcom_pcie_ep_get_io_resources(struct platform_device *pdev,
> --
> 2.25.1
>
