On Wed, May 09, 2018 at 02:01:34PM +0200, Niklas Cassel wrote: > For PCI, the second and third cell in ranges specifies the upper and > lower target address for address translation. This target address will > be used to program the internal address translation unit (iATU). > > The current device tree configuration will program the iATU to translate > CPU accesses to 0x08000000 to PCI address 0x0 (with TLP type MEM). > The device tree configuration also specifies that CPU acesses to > 0x0fe00000 will be translated to PCI address 0x0 (with TLP type I/O). > > We cannot have both I/O space and memory space at PCI address 0x0. > > The PCI code already uses the CPU address when assigning addresses to > memory BARs, so for memory space the PCI address should be the same as > the CPU address. This also matches how all other device trees using > snps,dw-pcie are configured. > > The existing configuration appears to work, even if it is incorrect. > For some reason the iATU doesn't obey the existing configuration, > and doesn't translate CPU accesses from 0x08000000 to PCI address 0x0. > > The reason why the existing configuration works at all is probably > because the default behavior, when there is no match, is to use the > untranslated address. This happens to work for memory space, since > it's a 1:1 mapping. However, instead of relying on this behavior, > let's configure the iATU correctly. > > Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxxxxx> > --- > arch/arm/boot/dts/qcom-apq8064.dtsi | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Hi Niklas, what's this patch status ? Please let me know if I have to keep it in the PCI tree queue, I think, if ACKed, it should probably go via the arm-soc tree. Thanks, Lorenzo > diff --git a/arch/arm/boot/dts/qcom-apq8064.dtsi b/arch/arm/boot/dts/qcom-apq8064.dtsi > index 5341a39c0392..148cf7e565f6 100644 > --- a/arch/arm/boot/dts/qcom-apq8064.dtsi > +++ b/arch/arm/boot/dts/qcom-apq8064.dtsi > @@ -1417,7 +1417,7 @@ > #address-cells = <3>; > #size-cells = <2>; > ranges = <0x81000000 0 0 0x0fe00000 0 0x00100000 /* I/O */ > - 0x82000000 0 0 0x08000000 0 0x07e00000>; /* memory */ > + 0x82000000 0 0x08000000 0x08000000 0 0x07e00000>; /* memory */ > interrupts = <GIC_SPI 238 IRQ_TYPE_NONE>; > interrupt-names = "msi"; > #interrupt-cells = <1>; > -- > 2.17.0 >
