[PATCH] PCI: xilinx-xdma: Enable legacy interrupts

[Manivannan Sadhasivam]

On Fri, Sep 19, 2025 at 11:13:30PM +0000, Ravi Kumar Bandi wrote:

+ Thippeswamy (author or 8d786149d78c)

> Starting with kernel 6.6.0, legacy interrupts from PCIe endpoints
> do not flow through the Xilinx XDMA root port bridge because
> interrupts are not enabled after initializing the port.
> 
> This issue is seen after XDMA driver received support for QDMA and
> underwent relevant code restructuring of old xdma-pl driver to
> xilinx-dma-pl (ref commit: 8d786149d78c).
> 

The above mentioned commmit added a new driver. So I don't see when the driver
restructuring happened.

> This patch re-enables legacy interrupts to use with PCIe endpoints
> with legacy interrupts.

s/legacy/INTx, here and everywhere.

> Tested the fix on a board with two endpoints
> generating legacy 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
> [...]
> 
> Signed-off-by: Ravi Kumar Bandi <ravib at amazon.com>

Missing Fixes tag and you should CC stable list for backporting.

- Mani

> ---
>  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
> 

-- 
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