[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: Question on PCIe Device Tree bindings, Was: [PATCH] xen/arm: domain_build: Ignore device nodes with invalid addresses
On Thu, Feb 4, 2021 at 2:36 PM Stefano Stabellini <sstabellini@xxxxxxxxxx> wrote: > > On Thu, 4 Feb 2021, Rob Herring wrote: > > On Thu, Feb 4, 2021 at 11:56 AM Stefano Stabellini > > <sstabellini@xxxxxxxxxx> wrote: > > > > > > Hi Rob, > > > > > > We have a question on the PCIe device tree bindings. In summary, we have > > > come across the Raspberry Pi 4 PCIe description below: > > > > > > > > > pcie0: pcie@7d500000 { > > > compatible = "brcm,bcm2711-pcie"; > > > reg = <0x0 0x7d500000 0x0 0x9310>; > > > device_type = "pci"; > > > #address-cells = <3>; > > > #interrupt-cells = <1>; > > > #size-cells = <2>; > > > interrupts = <GIC_SPI 148 IRQ_TYPE_LEVEL_HIGH>, > > > <GIC_SPI 148 IRQ_TYPE_LEVEL_HIGH>; > > > interrupt-names = "pcie", "msi"; > > > interrupt-map-mask = <0x0 0x0 0x0 0x7>; > > > interrupt-map = <0 0 0 1 &gicv2 GIC_SPI 143 > > > IRQ_TYPE_LEVEL_HIGH>; > > > msi-controller; > > > msi-parent = <&pcie0>; > > > > > > ranges = <0x02000000 0x0 0xc0000000 0x6 0x00000000 > > > 0x0 0x40000000>; > > > /* > > > * The wrapper around the PCIe block has a bug > > > * preventing it from accessing beyond the first 3GB of > > > * memory. > > > */ > > > dma-ranges = <0x02000000 0x0 0x00000000 0x0 0x00000000 > > > 0x0 0xc0000000>; > > > brcm,enable-ssc; > > > > > > pci@1,0 { > > > #address-cells = <3>; > > > #size-cells = <2>; > > > ranges; > > > > > > reg = <0 0 0 0 0>; > > > > > > usb@1,0 { > > > reg = <0x10000 0 0 0 0>; > > > resets = <&reset RASPBERRYPI_FIRMWARE_RESET_ID_USB>; > > > }; > > > }; > > > }; > > > > > > > > > Xen fails to parse it with an error because it tries to remap reg = > > > <0x10000 0 0 0 0> as if it was a CPU address and of course it fails. > > > > > > Reading the device tree description in details, I cannot tell if Xen has > > > a bug: the ranges property under pci@1,0 means that pci@1,0 is treated > > > like a default bus (not a PCI bus), hence, the children regs are > > > translated using the ranges property of the parent (pcie@7d500000). > > > > > > Is it possible that the device tree is missing device_type = > > > "pci" under pci@1,0? Or is it just implied because pci@1,0 is a child of > > > pcie@7d500000? > > > > Indeed, it should have device_type. Linux (only recently due to > > another missing device_type case) will also look at node name, but > > only 'pcie'. > > > > We should be able to create (or extend pci-bus.yaml) a schema to catch > > this case. > > Ah, that is what I needed to know, thank you! Is Linux considering a > node named "pcie" as if it has device_type = "pci"? Yes, it was added for Rockchip RK3399 to avoid a DT update and regression. > In Xen, also to cover the RPi4 case, maybe I could add a check for the > node name to be "pci" or "pcie" and if so Xen could assume device_type = > "pci". I assume this never worked for RPi4 (and Linux will have the same issue), so can't we just update the DT in this case? Rob
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |