Re: [PATCH v2 2/2] PCI: starfive: Simplify event doorbell bitmap initialization in pcie-starfive

Manivannan Sadhasivam
2025-04-19T10:32:08Z

On Sun, Mar 16, 2025 at 10:42:46PM +0530, Anand Moon wrote:
> The events_bitmap initialization in starfive_pcie_probe() previously
> masked out the PLDA_AXI_DOORBELL and PLDA_PCIE_DOORBELL events.
>
> These masking has been removed, allowing these events to be included
> in the bitmap. With this change ensures that all interrupt events are
> properly accounted for and may be necessary for handling doorbell
> events in certain use cases.
>
> PCIe Doorbell Events: These are typically used to notify a device about
> an event or to trigger an action. For example, a host system can write
> to a doorbell register on a PCIe device to signal that new data is
> available or that an operation should start12.
>
> AXI-PCIe Bridge: This bridge acts as a protocol converter between AXI
> (Advanced eXtensible Interface) and PCIe (Peripheral Component Interconnect
> Express) domains. It allows transactions to be converted and communicated
> between these two different protocols3.
>

Are these events used in the driver for any purpose? Others have mentioned a
potential irq storm issue with these interrupts also. So unless you want to
enable these events for a specific purpose/usecase, it is better to keep them
masked out.

- Mani

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