On Mon, Sep 26, 2022 at 09:31:34PM +0800, Shuai Xue wrote: > 在 2022/9/23 PM11:54, Jonathan Cameron 写道: > >> I found a similar definition in arch/ia64/pci/pci.c . > >> > >> #define PCI_SAL_ADDRESS(seg, bus, devfn, reg) \ > >> (((u64) seg << 24) | (bus << 16) | (devfn << 8) | (reg)) > >> > >> Should we move it into a common header first? > > > > Maybe. The bus, devfn, reg part is standard bdf, but I don't think > > the PCI 6.0 spec defined a version with the seg in the upper bits. > > I'm not sure if we want to adopt that in LInux. > > I found lots of code use seg,bus,devfn,reg with format "%04x:%02x:%02x.%x", > I am not quite familiar with PCIe spec. What do you think about it, Bjorn? The PCIe spec defines an address encoding for bus/device/function/reg for the purposes of ECAM (PCIe r6.0, sec 7.2.2), but as far as I know, it doesn't define anything similar that includes the segment. The segment is really outside the scope of PCIe because each segment is a completely separate PCIe hierarchy. So I probably wouldn't make this a generic definition. But if/when you print things like this out, please do use the format spec you mentioned above so it matches the style used elsewhere. Bjorn
