On 07/08/2016 11:39 AM, Arnd Bergmann wrote: > On Friday, July 8, 2016 1:28:10 AM CEST Niklas Cassel wrote: >> From: Niklas Cassel <[email protected]> >> >> - Increase config size. When using a PCIe switch, >> the previous config size only had room for one device. >> - Add bus range. Inherited optional property. >> - Map downstream I/O to PCI address 0. We can map it to any >> address, but let's be consistent with other drivers. >> >> Signed-off-by: Niklas Cassel <[email protected]> >> --- >> Documentation/devicetree/bindings/pci/axis,artpec6-pcie.txt | 7 ++++--- >> 1 file changed, 4 insertions(+), 3 deletions(-) >> >> diff --git a/Documentation/devicetree/bindings/pci/axis,artpec6-pcie.txt >> b/Documentation/devicetree/bindings/pci/axis,artpec6-pcie.txt >> index 330a45b..5ecaea1 100644 >> --- a/Documentation/devicetree/bindings/pci/axis,artpec6-pcie.txt >> +++ b/Documentation/devicetree/bindings/pci/axis,artpec6-pcie.txt >> @@ -24,16 +24,17 @@ Example: >> compatible = "axis,artpec6-pcie", "snps,dw-pcie"; >> reg = <0xf8050000 0x2000 >> 0xf8040000 0x1000 >> - 0xc0000000 0x1000>; >> + 0xc0000000 0x2000>; > If this is your config space size > >> num-lanes = <2>; >> + bus-range = <0x00 0xff>; > then the bus range looks too large. These two are typically connected. > I couldn't immediately see which config space access function is > used, but if you have 0x1000 bytes per bus, then the bus range matching > a 0x2000 byte config space would be either <0x00 0x01> or <0x00 0x02> > depending whether the root bus is part of that range.
I see your point, a config space size of 0x2000 is only enough to hold two configuration space headers. However, all other PCIe controllers based on Synopsys DesignWare IP with a config space size of 0x2000, uses a bus-range of 0x0-0xff. (Except hisilicon which for some reason uses 0x0-0xf). Isn't it better to be consistent with the other DesignWare based controllers? Also, isn't is possible to have a device behind bus 1, then nothing behind bus 2, and then a device behind bus 3? Not sure if this could actually happen though, since Linux appears to assign the bus numbers, unless already defined by BIOS.
