[PATCH v2] PCI: xilinx-xdma: Enable INTx interrupts

[Bjorn Helgaas]

[+cc Stefan, Sean]

On Sat, Sep 20, 2025 at 10:52:32PM +0000, Ravi Kumar Bandi wrote:
> The pcie-xilinx-dma-pl driver does not enable INTx interrupts
> after initializing the port, preventing INTx interrupts from
> PCIe endpoints from flowing through the Xilinx XDMA root port
> bridge. This issue affects kernel 6.6.0 and later versions.
> 
> This patch allows INTx interrupts generated by PCIe endpoints
> to flow through the root port. Tested the fix on a board with
> two endpoints generating INTx interrupts. Interrupts are
> properly detected and serviced. The /proc/interrupts output
> shows:
> 
> [...]
> 32:        320          0  pl_dma:RC-Event  16 Level     400000000.axi-pcie, azdrv
> 52:        470          0  pl_dma:RC-Event  16 Level     500000000.axi-pcie, azdrv
> [...]
> 
> Changes since v1::
> - Fixed commit message per reviewer's comments
> 
> Fixes: 8d786149d78c ("PCI: xilinx-xdma: Add Xilinx XDMA Root Port driver")
> Cc: stable at vger.kernel.org
> Signed-off-by: Ravi Kumar Bandi <ravib at amazon.com>

Hi Ravi, obviously you tested this, but I don't know how to reconcile
this with Stefan's INTx fix at
https://lore.kernel.org/r/20251021154322.973640-1-stefan.roese@mailbox.org

Does Stefan's fix need to be squashed into this patch?

> ---
>  drivers/pci/controller/pcie-xilinx-dma-pl.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/pci/controller/pcie-xilinx-dma-pl.c b/drivers/pci/controller/pcie-xilinx-dma-pl.c
> index b037c8f315e4..cc539292d10a 100644
> --- a/drivers/pci/controller/pcie-xilinx-dma-pl.c
> +++ b/drivers/pci/controller/pcie-xilinx-dma-pl.c
> @@ -659,6 +659,12 @@ static int xilinx_pl_dma_pcie_setup_irq(struct pl_dma_pcie *port)
>  		return err;
>  	}
>  
> +	/* Enable interrupts */
> +	pcie_write(port, XILINX_PCIE_DMA_IMR_ALL_MASK,
> +		   XILINX_PCIE_DMA_REG_IMR);
> +	pcie_write(port, XILINX_PCIE_DMA_IDRN_MASK,
> +		   XILINX_PCIE_DMA_REG_IDRN_MASK);
> +
>  	return 0;
>  }
>  
> -- 
> 2.47.3
>