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    Subject[PATCH 15/17] pci: of_property: Add the interrupt-controller property in PCI device nodes
    Date
    PCI devices and bridges DT nodes created during the PCI scan are created
    with the interrupt-map property set to handle interrupts.

    In order to set this interrupt-map property at a specific level, a
    phandle to the parent interrupt controller is needed.
    On systems that are not fully described by a device-tree, the parent
    interrupt controller may be unavailable (i.e. not described by the
    device-tree).

    As mentioned in the [1], avoiding the use of the interrupt-map property
    and considering a PCI device as an interrupt controller itself avoid the
    use of a parent interrupt phandle.

    In that case, the PCI device itself as an interrupt controller is
    responsible for routing the interrupts described in the device-tree
    world (DT overlay) to the PCI interrupts.

    Add the 'interrupt-controller' property in the PCI device DT node.

    [1]: https://lore.kernel.org/lkml/CAL_Jsq+je7+9ATR=B6jXHjEJHjn24vQFs4Tvi9=vhDeK9n42Aw@mail.gmail.com/

    Signed-off-by: Herve Codina <herve.codina@bootlin.com>
    ---
    drivers/pci/of_property.c | 24 ++++++++++++++++++++++++
    1 file changed, 24 insertions(+)

    diff --git a/drivers/pci/of_property.c b/drivers/pci/of_property.c
    index c2c7334152bc..9f8b940029ed 100644
    --- a/drivers/pci/of_property.c
    +++ b/drivers/pci/of_property.c
    @@ -183,6 +183,26 @@ static int of_pci_prop_interrupts(struct pci_dev *pdev,
    return of_changeset_add_prop_u32(ocs, np, "interrupts", (u32)pin);
    }

    +static int of_pci_prop_intr_ctrl(struct pci_dev *pdev, struct of_changeset *ocs,
    + struct device_node *np)
    +{
    + int ret;
    + u8 pin;
    +
    + ret = pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &pin);
    + if (ret != 0)
    + return ret;
    +
    + if (!pin)
    + return 0;
    +
    + ret = of_changeset_add_prop_u32(ocs, np, "#interrupt-cells", 1);
    + if (ret)
    + return ret;
    +
    + return of_changeset_add_prop_bool(ocs, np, "interrupt-controller");
    +}
    +
    static int of_pci_prop_intr_map(struct pci_dev *pdev, struct of_changeset *ocs,
    struct device_node *np)
    {
    @@ -334,6 +354,10 @@ int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs,
    ret = of_pci_prop_intr_map(pdev, ocs, np);
    if (ret)
    return ret;
    + } else {
    + ret = of_pci_prop_intr_ctrl(pdev, ocs, np);
    + if (ret)
    + return ret;
    }

    ret = of_pci_prop_ranges(pdev, ocs, np);
    --
    2.44.0

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