On Tue, Aug 14, 2012 at 1:12 PM, Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx> wrote: > On Thu, Jul 26, 2012 at 09:55:12PM +0200, Thierry Reding wrote: >> diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra20.dtsi >> index a094c97..c886dff 100644 >> --- a/arch/arm/boot/dts/tegra20.dtsi >> +++ b/arch/arm/boot/dts/tegra20.dtsi >> @@ -199,6 +199,68 @@ >> #size-cells = <0>; >> }; >> >> + pcie-controller { >> + compatible = "nvidia,tegra20-pcie"; >> + reg = <0x80003000 0x00000800 /* PADS registers */ >> + 0x80003800 0x00000200 /* AFI registers */ >> + 0x81000000 0x01000000 /* configuration space */ >> + 0x90000000 0x10000000>; /* extended configuration space */ >> + interrupts = <0 98 0x04 /* controller interrupt */ >> + 0 99 0x04>; /* MSI interrupt */ >> + status = "disabled"; >> + >> + ranges = <0 0 0 0x80000000 0x00001000 /* root port 0 */ >> + 0 1 0 0x81000000 0x00800000 /* port 0 config space */ >> + 0 2 0 0x90000000 0x08000000 /* port 0 ext config space */ >> + 0 3 0 0x82000000 0x00010000 /* port 0 downstream I/O */ >> + 0 4 0 0xa0000000 0x08000000 /* port 0 non-prefetchable memory */ >> + 0 5 0 0xb0000000 0x08000000 /* port 0 prefetchable memory */ >> + >> + 1 0 0 0x80001000 0x00001000 /* root port 1 */ >> + 1 1 0 0x81800000 0x00800000 /* port 1 config space */ >> + 1 2 0 0x98000000 0x08000000 /* port 1 ext config space */ >> + 1 3 0 0x82010000 0x00010000 /* port 1 downstream I/O */ >> + 1 4 0 0xa8000000 0x08000000 /* port 1 non-prefetchable memory */ >> + 1 5 0 0xb8000000 0x08000000>; /* port 1 prefetchable memory */ > > I've been thinking about this some more. The translations for both the > regular and extended configuration spaces are configured in the top- > level PCIe controller. It is therefore wrong how they are passed to the > PCI host bridges via the ranges property. > > I remember Mitch saying that it should be passed down to the children > because it is partitioned among them, but since the layout is compatible > with ECAM, the partitioning isn't as simple as what's in the tree. In > fact the partitions will be dependent on the number of devices attached > to the host bridges. I don't understand this last bit about the number of devices attached to the host bridges. Logically, the host bridge has a bus number aperture that you can know up front, even before you know anything about what devices are below it. On x86, for example, the ACPI _CRS method has something like "[bus 00-7f]" in it, which means that any buses in that range are below this bridge. That doesn't tell us anything about which buses actually have devices on them, of course; it's just analogous to the secondary and subordinate bus number registers in a P2P bridge. >> + >> + #address-cells = <3>; >> + #size-cells = <1>; >> + >> + pci@0 { >> + device_type = "pciex"; >> + reg = <0 0 0 0x1000>; >> + status = "disabled"; >> + >> + #address-cells = <3>; >> + #size-cells = <2>; >> + >> + ranges = <0x80000000 0 0 0 1 0 0 0x00800000 /* config space */ >> + 0x90000000 0 0 0 2 0 0 0x08000000 /* ext config space */ >> + 0x81000000 0 0 0 3 0 0 0x00010000 /* I/O */ >> + 0x82000000 0 0 0 4 0 0 0x08000000 /* non-prefetchable memory */ >> + 0xc2000000 0 0 0 5 0 0 0x08000000>; /* prefetchable memory */ >> + >> + nvidia,num-lanes = <2>; >> + }; >> + >> + pci@1 { >> + device_type = "pciex"; >> + reg = <1 0 0 0x1000>; >> + status = "disabled"; >> + >> + #address-cells = <3>; >> + #size-cells = <2>; >> + >> + ranges = <0x80000000 0 0 1 1 0 0 0x00800000 /* config space */ >> + 0x90000000 0 0 1 2 0 0 0x08000000 /* ext config space */ >> + 0x81000000 0 0 1 3 0 0 0x00010000 /* I/O */ >> + 0x82000000 0 0 1 4 0 0 0x08000000 /* non-prefetchable memory */ >> + 0xc2000000 0 0 1 5 0 0 0x08000000>; /* prefetchable memory */ >> + >> + nvidia,num-lanes = <2>; >> + }; >> + }; > > The same is true for the ranges properties of the PCI host bridge nodes. > Which part of the configuration spaces maps to the children of the > respective host bridge depends on the actual device hierarchy. > > Would it be possible to alternatively pass the complete range to the > children without further partitioning? > > The driver doesn't actually care about the ranges property and only uses > the values specified in the reg property of the pcie-controller node. > > Thierry -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html