> [+cc Frank, who asked the same question about DT] > > On Thu, Feb 20, 2025 at 08:54:06PM +0100, Lorenzo Bianconi wrote: > > On Feb 20, Bjorn Helgaas wrote: > > > On Sun, Feb 02, 2025 at 08:34:24PM +0100, Lorenzo Bianconi wrote: > > > > Configure PBus base address and address mask to allow the hw > > > > to detect if a given address is on PCIE0, PCIE1 or PCIE2. > > > > > +#define PCIE_EN7581_PBUS_ADDR(_n) (0x00 + ((_n) << 3)) > > > > +#define PCIE_EN7581_PBUS_ADDR_MASK(_n) (0x04 + ((_n) << 3)) > > > > +#define PCIE_EN7581_PBUS_BASE_ADDR(_n) \ > > > > + ((_n) == 2 ? 0x28000000 : \ > > > > + (_n) == 1 ? 0x24000000 : 0x20000000) > > > > > > Are these addresses something that should be expressed in devicetree? > > > > Do you have any example/pointer for it? > > > > > It seems unusual to encode addresses directly in a driver. > > > > AFAIK they are fixed for EN7581 SoC. > > So this is used to detect if a given address is on PCIE0, PCIE1 or > PCIE2. What does that mean? There are no other mentions of PCIE0 etc > in the driver, but maybe they match up to "pcie0/1/2" in > arch/arm64/boot/dts/mediatek/mt7988a.dtsi? > > It looks like you use PCIE_EN7581_PBUS_ADDR(slot), where "slot" came > from of_get_pci_domain_nr(), which suggests that these might be three > separate Root Ports? I was using pci_domain to detect the specific PCIe controller (something similar to what is done here [0]) but I agree with Frank, it does not seem completely correct. [0] https://github.com/torvalds/linux/blob/master/drivers/pci/controller/pcie-mediatek.c#L1048 > > Are we talking about an MMIO address that an endpoint driver uses for > readw() etc, and this code configures the hardware apertures through > the host bridge? Seems like that would be related to the "ranges" > properties in DT. I guess so, but I do not have any documentation about pbus-csr (adding Hui in the loop). As pointed out by Frank, do you agree to add these info in the dts? Something like: pcie0: pcie@1fc00000 { .... mediatek,pbus-csr = <&pbus_csr 0x0 0x20000000 0x4 0xfc000000>; .... }; pcie1: pcie@1fc20000 { .... mediatek,pbus-csr = <&pbus_csr 0x8 0x24000000 0xc 0xfc000000>; .... }; @Hui: can you please provide a better explanation about pbus-csr usage? Regards, Lorenzo > > Bjorn
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