On 2015/10/13 23:00, Arnd Bergmann wrote: > On Tuesday 13 October 2015 14:49:07 Gabriele Paoloni wrote: >>> On Monday 12 October 2015 16:35:45 Bjorn Helgaas wrote: >>>> >>>>> +{ >>>>> + u64 addr; >>>>> + struct device_node *msi_node; >>>>> + struct resource res; >>>>> + struct device_node *np = pp->dev->of_node; >>>>> + struct hisi_pcie *pcie = to_hisi_pcie(pp); >>>>> + >>>>> + msi_node = of_parse_phandle(np, "msi-parent", 0); >>>>> + if (!msi_node) { >>>>> + dev_err(pp->dev, "failed to find msi-parent\n"); >>>>> + return -EINVAL; >>>>> + } >>>>> + of_address_to_resource(msi_node, 0, &res); >>>> >>>> Does this use the "msi-parent" node in the same way as other drivers >>>> do? I'm sure there must be other places where we extract struct >>>> resource information from an "msi-parent" node, but I don't see them. >>>> >>>> I'm trying to verify that this isn't some kind of incompatible >>>> extension of the "msi-parent" property. I cc'd Arnd and Rob (DT >>>> experts). >>> >>> This is not ok, what this does is that it relies on a particular >>> implementation of the MSI controller and directly accesses its >>> registers. >> >> Hi Arnd, thanks for reviewing. >> >> What we do is to retrieve the msi-parent physical address and we store it >> in our internal PCIe register locations... > > Ah, thanks for the clarification, I missed that part. > >> So we do not operate directly on the msi controller registers... >> >> So I wonder if the current implementation is Ok to retrieve the >> msi-parent address.... > > Not sure. Why do you do this? Normally the PCI host does not know > or care about the address of the MSI controller, because the messages > are just passed up to the parent bus as DMA transfers. > Hi Arnd, In Hip05 PCIe host, it uses GITS_TRANSLATER's address to get TLP package which contains MSI address and MSI data, and then combine BDF and MSI data to a 32 bit data which will be writen to GITS_TRANSLATER register of ITS. I think maybe this is a defect of our PCIe controller. > I don't think what you do here is safe because the 'reg' property > of the MSI controller might point to the address that is used for > the message directly. I see your point, however we must get address of GITS_TRANSLATER and set it to PCIe host. How about adding necessary comments here? Best Regards, Zhou > > Arnd > > . > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html