On Wed, 2018-01-31 at 10:02 -0600, Rob Herring wrote:

On Wed, Jan 31, 2018 at 1:41 AM, Ryder Lee [off-list ref] wrote:

quoted

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@mediatek.com>
---
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.

quoted

+               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?

Okay, I will try it out and and see if the code gets better or worse.
 

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.

Sure. I will loop more people in next version.

Thanks

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek