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

["Bandi, Ravi Kumar" <ravib@amazon.com>]

Hello Mani,

Thanks for reviewing the patch.

> On Sep 20, 2025, at 8:51 AM, Manivannan Sadhasivam <mani@kernel.org> wrote:
> 
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe.
> 
> 
> 
> On Fri, Sep 19, 2025 at 11:13:30PM +0000, Ravi Kumar Bandi wrote:
> 
> + Thippeswamy (author or 8d786149d78c)

Thanks for adding.

> 
>> 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.

Ack. I’ve updated the commit message in the v2.

> 
>> This patch re-enables legacy interrupts to use with PCIe endpoints
>> with legacy interrupts.
> 
> s/legacy/INTx, here and everywhere.

Ack. Taken care in v2.

> 
>> 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@amazon.com>
> 
> Missing Fixes tag and you should CC stable list for backporting.

Ack. Added the tag and CC’ed stable list in v2.

I’ll submit v2 with the comments incorporated, please review.

Thanks,
Ravi

> 
> - 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
>> 
> 
> --
> மணிவண்ணன் சதாசிவம்