Hi Richard,

Thanks for debugging this issue. One question below.

Richard Zhu writes:
> MSI_EN of iMX PCIe RC would be asserted when
> PCIEPORTBUS driver is selected.
> Thus, the MSI works fine on iMX PCIe before.
> Make a double check on this bit, and assert it
> when it is not set and MSI is supported.
> Otherwise, the MSI wouldn't be triggered although
> the EP is present and the MSIs are assigned.
>
> Signed-off-by: Richard Zhu <hongxing....@nxp.com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c 
> b/drivers/pci/controller/dwc/pci-imx6.c
> index 26087b3..6c3e56b 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -74,6 +74,7 @@ struct imx6_pcie {
>  #define PHY_PLL_LOCK_WAIT_USLEEP_MAX 200
>  
>  /* PCIe Root Complex registers (memory-mapped) */
> +#define PCI_MSI_CAP                          0x50
>  #define PCIE_RC_LCR                          0x7c
>  #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN1     0x1
>  #define PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2     0x2
> @@ -926,6 +927,7 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>       struct resource *dbi_base;
>       struct device_node *node = dev->of_node;
>       int ret;
> +     u16 val;
>  
>       imx6_pcie = devm_kzalloc(dev, sizeof(*imx6_pcie), GFP_KERNEL);
>       if (!imx6_pcie)
> @@ -1070,6 +1072,14 @@ static int imx6_pcie_probe(struct platform_device 
> *pdev)
>       ret = imx6_add_pcie_port(imx6_pcie, pdev);
>       if (ret < 0)
>               return ret;
> +     if (IS_ENABLED(CONFIG_PCI_MSI)) {
> +             val = dw_pcie_readw_dbi(pci, PCI_MSI_CAP + PCI_MSI_FLAGS);
> +             if ((val & PCI_MSI_FLAGS_ENABLE) == 0) {
> +                     val |= PCI_MSI_FLAGS_ENABLE;

Why not assert the PCI_MSI_FLAGS_ENABLE flag unconditionally here?

> +                     dw_pcie_writew_dbi(pci, PCI_MSI_CAP +
> +                                     PCI_MSI_FLAGS, val);
> +             }
> +     }
>  
>       return 0;
>  }

baruch

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