Re: [PATCH v4] PCI: dw-rockchip: Move the INTx irq setup to probe

[Shawn Lin <shawn.lin@rock-chips.com>]

Hi Mani, Bjorn

在 2026/09/24 星期四 12:06, Shawn Lin 写道:
> Since commit b376b3ff9cb0 ("PCI: dw-rockchip: Implement .reset_root_port()
> and use for link down"), .reset_root_port() re-runs the host ops .init()
> callback to reprogram the Root Complex after a controller reset. That
> works for the register programming, but .init() is not re-entrant: it
> also creates the INTx irq domain and installs the chained INTx handler.
> Every root port reset therefore ends up with a second irq domain
> registered for the same fwnode: the previous one is leaked, as it is
> never removed, and worse, the INTx virqs of the downstream PCI devices
> were allocated in the previous irq domain and are never re-mapped, while
> the chained handler now looks up virqs in the new, empty domain. After a
> link down recovery, INTx interrupts are silently lost.
> 
> Fix it by moving the of_irq_get_byname() lookup, the INTx irq domain
> creation and the chained handler installation out of .init() and into
> rockchip_pcie_configure_rc(), just before dw_pcie_host_init(). The
> lookup has to happen before the host is initialized, because
> dw_pcie_host_init() enumerates the bus and probes the downstream
> devices, and pci_assign_irq() maps their INTx interrupts at that point:
> if the domain does not exist yet, the mapping fails and the devices end
> up without a usable INTx. This also mirrors how the qcom driver requests
> its global IRQ, and leaves .init() with nothing but idempotent register
> programming, so both .reset_root_port() and dw_pcie_resume_noirq() can
> safely re-run it. Re-running of_irq_get_byname() on every resume is also
> gone.
> 

The offending commit was introduced in this cycle. Is there an
opportunity to merge this fix into 7.3?

> Fixes: b376b3ff9cb0 ("PCI: dw-rockchip: Implement .reset_root_port() and use for link down")
> Suggested-by: Niklas Cassel <cassel@kernel.org>
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> ---
> 
> Changes in v4:
> - drop the code comment (Niklas)
> - create the INTx irq domain before dw_pcie_host_init() instead of
>    after it. dw_pcie_host_init() enumerates the bus and probes the
>    downstream devices, and their INTx interrupts get mapped at that
>    point, so registering the domain afterwards left every downstream
>    device without a usable INTx (flagged by the Sashiko review).
> - this also removes the failing steps behind dw_pcie_host_init(), so
>    there is no error path left that would return with the root bus
>    registered and the rockchip structure about to be freed (flagged by
>    the Sashiko review).
> 
> Changes in v3:
> - split devm-managed part into a seperate patch
> 
> Changes in v2:
> - Moved the of_irq_get_byname() lookup, the INTx irq domain creation
>    and the chained handler installation out of the host ops .init()
>    callback into rockchip_pcie_configure_rc(), right after
>    dw_pcie_host_init(), as suggested by Niklas Cassel. This supersedes
>    v1 patch 1/2, as .init() no longer creates the irq domain, and
>    removes the rockchip_pcie_host_hw_init() helper from v1.
> - Made the INTx irq domain devm-managed with
>    devm_irq_domain_instantiate() and uninstall the chained handler
>    through a devres action, addressing the probe failure leak and
>    use-after-free flagged by the Sashiko review.
> 
>   drivers/pci/controller/dwc/pcie-dw-rockchip.c | 27 +++++++++++++--------------
>   1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index 1497686..bd86e32c 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -422,23 +422,9 @@ static void rockchip_pcie_stop_link(struct dw_pcie *pci)
>   static int rockchip_pcie_host_init(struct dw_pcie_rp *pp)
>   {
>   	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> -	struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
> -	struct device *dev = rockchip->pci.dev;
> -	int irq, ret;
> -
> -	irq = of_irq_get_byname(dev->of_node, "legacy");
> -	if (irq < 0)
> -		return irq;
>   
>   	pci->dbi_base2 = pci->dbi_base + PCIE_TYPE0_HDR_DBI2_OFFSET;
>   
> -	ret = rockchip_pcie_init_irq_domain(rockchip);
> -	if (ret < 0)
> -		dev_err(dev, "failed to init irq domain\n");
> -
> -	irq_set_chained_handler_and_data(irq, rockchip_pcie_intx_handler,
> -					 rockchip);
> -
>   	rockchip_pcie_configure_l1ss(pci);
>   	rockchip_pcie_enable_l0s(pci);
>   	pp->bridge->reset_root_port = rockchip_pcie_rc_reset_root_port;
> @@ -731,6 +717,19 @@ static int rockchip_pcie_configure_rc(struct platform_device *pdev,
>   				 PCIE_CLIENT_SET_MODE(PCIE_CLIENT_MODE_RC),
>   				 PCIE_CLIENT_GENERAL_CON);
>   
> +	irq = of_irq_get_byname(dev->of_node, "legacy");
> +	if (irq < 0)
> +		return irq;
> +
> +	ret = rockchip_pcie_init_irq_domain(rockchip);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to init irq domain\n");
> +		return ret;
> +	}
> +
> +	irq_set_chained_handler_and_data(irq, rockchip_pcie_intx_handler,
> +					 rockchip);
> +
>   	pp = &rockchip->pci.pp;
>   	pp->ops = &rockchip_pcie_host_ops;
>   


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