Re: [PATCH v4 11/18] PCI: rcar-gen4: Take over the iMSI-RX interrupt

[Marek Vasut <marek.vasut@mailbox.org>]

On 10/15/26 5:30 AM, Koichiro Den wrote:
> On R-Car Gen4 SoCs, intreq_pcim_sub ("msi") carries more than the
> integrated MSI receiver: the controller's reset requests and the Root
> Port's PME and bandwidth notifications are signalled on the same line,
> and the following patches need to handle them. With the DesignWare core
> owning the line through its chained handler, the driver would have to
> hook into that handler when iMSI-RX is used and request the line itself
> otherwise.
> 
> Instead, request the interrupt in the driver in all configurations and
> set pp->msi_irq[0] to -ENODEV so the core does not install its chained
> handler, as spear13xx, keembay and dra7xx do. The handler demultiplexes
> the MSIs through dw_handle_msi_irq() when the APP block reports
> msi_ctrl_int, in hard IRQ context like the chained handler did. With an
> external MSI controller or pci=nomsi the iMSI-RX is not set up, so keep
> msi_ctrl_int masked, and the handler has nothing to do there yet.
> 
> Request the interrupt in probe with IRQF_NO_AUTOEN and enable it at the
> end of .init(), before endpoint drivers can use MSIs from their probe.
> Disable it in .deinit(), before the controller is powered down, and
> around a Root Port reset, as the handler reads the controller registers.
> Suspend and resume go through the same two callbacks.
> 
> The DT routes downstream INTx to the same line, but the driver has never
> supported INTx (no INTx domain, INTx enables never set), so requesting
> the line exclusively takes nothing away.
> 
> Signed-off-by: Koichiro Den <den@valinux.co.jp>
Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>