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We're removing .cpu_addr_fixup() because > > > > it's a workaround for defects in the DT description. See these > > > > commits, for example: > > > > > > > > befc86a0b354 ("PCI: dwc: Use parent_bus_offset to remove need for .cpu_addr_fixup()") > > > > b9812179f601 ("PCI: imx6: Remove imx_pcie_cpu_addr_fixup()") > > > > 07ae413e169d ("PCI: intel-gw: Remove intel_pcie_cpu_addr()") > > > > > > I’m a bit confused about the following question: > > > After removing cpu_addr_fixup, should we use pci->parent_bus_offset > > > to store the offset value, or should pci->parent_bus_offset remain > > > 0? > > > > If you needed qilai_pcie_cpu_addr_fixup(), I would expect your > > dw_pcie.parent_bus_offset to be non-zero because parent_bus_offset is > > used instead of ->cpu_addr_fixup(). > > > > In this SoC, the dw_pcie.parent_bus_offset should be set to the value of the > config register base address. Setting the dw_pcie.parent_bus_offset to a > non-zero value seems to occur only in the path that uses ->cpu_addr_fixup(). > > The parent_bus_offset is generally used instead of ->cpu_addr_fixup() throughout > most of the code, but its assignment still seems to rely on ->cpu_addr_fixup() > when it needs to be set to a non-zero value. > If no other method exists to set up dw_pcie.parent_bus_offset, can we keep using > ->cpu_addr_fixup() for the assignment? Correct your dts file. See below > > > > In the commit message: > > > befc86a0b354 ("PCI: dwc: Use parent_bus_offset to remove need for .cpu_addr_fixup()") > > > We know the parent_bus_offset, either computed from a DT reg > > > property (the offset is the CPU physical addr - the > > > 'config'/'addr_space' address on the parent bus) or from a > > > .cpu_addr_fixup() (which may have used a host bridge window > > > offset). > > > > > > We know that "the offset is the CPU physical addr - the > > > 'config'/'addr_space' address on the parent bus". > > > > > > However, in dw_pcie_host_get_resources(), it passes pp->cfg0_base, > > > which is parsed from the device tree using "config", as the > > > cpu_phys_addr parameter to dw_pcie_parent_bus_offset(). It also > > > passes "config" as the 2nd parameter to dw_pcie_parent_bus_offset(). > > > > > > In dw_pcie_parent_bus_offset(), the 2nd parameter is used to get the > > > index from the devicetree "reg-names" field, and the result is used > > > as the 'config'/'addr_space' address. > > > > > > It seems that the same value is being obtained through a different > > > method, and the return value appears to be 0. Could I be > > > misunderstanding something? I missed prevous discussion. Actually address convert happen at PCIe's parent bus fabric. If your DTS correct reflect this address convert, you needn't cpu_addr_fixup() at all. bus { ranges = (0x2000_00000, 0x1000_0000, 0x1000_0000) ^^^^^ pcie@xxxx { reg = <0x2000_00000, 0x1000>; reg-names = ; } } 0x2000_0000 is actaully address input to your PCI controller although CPU use 0x1000_0000. "bus" fabric convert 0x1000_0000 to 0x2000_0000 So dwc common code already can handle this to auto calucate parent_bus_offset base on ranges of bus. Frank > > > > Sincerely, > Randolph