On Tue, 27 Sep 2022 13:13:29 +0800 Shuai Xue <xueshuai@xxxxxxxxxxxxxxxxx> wrote: > 在 2022/9/27 AM1:18, Bjorn Helgaas 写道: > > 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. > > Thank you for your explanation. > > > > > 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. > > > > Agree. The print format of bus/device/function/reg is "%04x:%02x:%02x.%x", > so I named the PMU as the same format. Then the usage flow would be: > > - lspci to get the device root port in format seg/bus/device/function/reg. > 10:00.0 PCI bridge: Device 1ded:8000 (rev 01) > - select its PMU name pcie_bdf_100000. > - monitor with perf: > perf stat -a -e pcie_bdf_200/Rx_PCIe_TLP_Data_Payload/ I think you probably want something in there to indicate it's an RP and the bdf part may be redundant... Jonathan > > Bjorn and Jonathan, are you happy with this flow? > > Thank you. > > Best Regards, > Shuai >
