On Wed, Jan 31, 2018 at 1:41 AM, Ryder Lee <ryder.lee@xxxxxxxxxxxx> wrote:
> A root complex usually consist of a host bridge and multiple P2P bridges,
> and someone may express that in the form of a root node with many subnodes
> and list all four interrupts for each slot (child node) in the root node
> like this:
>
> pcie-controller {
> ...
> interrupt-map-mask = <0xf800 0 0 7>;
> interrupt-map = <0x0000 0 0 {INTx} &{interrupt parent} ...>
> 0x0800 0 0 {INTx} &{interrupt parent} ...>;
>
> pcie@0,0 {
> reg = <0x0000 0 0 0 0>;
> ...
> };
>
> pcie@1,0 {
> reg = <0x0800 0 0 0 0>;
> ...
> };
> };
>
> As shown above, we'd like to propagate IRQs from a root port to the devices
> in the hierarchy below it in this way. However, it seems that the current
> parser couldn't handle such cases and will get something unexpected below:
>
> pcieport 0000:00:01.0: assign IRQ: got 213
> igb 0000:01:00.0: assign IRQ: got 212
>
> There is a device which is connected to 2nd slot, but the port doesn't share
> the same IRQ with its downstream devices. The problem here is that, if the
> loop found a P2P bridge, it wouldn't check whether the reg property exists
> in ppnode or not but just pass the subordinate devfn to of_irq_parse_raw(),
> thus the subsequent flow couldn't correctly resolve them.
>
> Fix this by adding a check to fallback to standard device tree parsing.
>
> Signed-off-by: Ryder Lee <ryder.lee@xxxxxxxxxxxx>
> ---
> Please refer to the previous discussion thread: https://patchwork.ozlabs.org/patch/829108/
> ---
> drivers/of/of_pci_irq.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/of/of_pci_irq.c b/drivers/of/of_pci_irq.c
> index 3a05568..e445866 100644
> --- a/drivers/of/of_pci_irq.c
> +++ b/drivers/of/of_pci_irq.c
> @@ -86,8 +86,18 @@ int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq
> out_irq->np = ppnode;
> out_irq->args_count = 1;
> out_irq->args[0] = pin;
> - laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
> - laddr[1] = laddr[2] = cpu_to_be32(0);
> +
> + if (!dn && ppnode) {
I would think whether you have a child device in DT or not is
irrelevant. If it's the bridge address you need to look at for
resolving interrupts, that would be true regardless.
> + const __be32 *addr;
> +
> + addr = of_get_property(ppnode, "reg", NULL);
> + if (addr)
> + memcpy(laddr, addr, 3);
Can't you just adjust pdev to be ppdev in this case and then use the
existing code to set laddr?
Please copy the powerpc list on this. I worry that touching this
function will break something.
BTW, this code is moving to drivers/pci/ in 4.16.
> + } else {
> + laddr[0] = cpu_to_be32((pdev->bus->number << 16) | (pdev->devfn << 8));
> + laddr[1] = laddr[2] = cpu_to_be32(0);
> + }
> +
> rc = of_irq_parse_raw(laddr, out_irq);
> if (rc)
> goto err;
> --
> 1.9.1
>
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