Hi Pantelis,
coming back to this topic:
On 2016-06-09 08:03, Jan Kiszka wrote:
> OK, trial and error, and some interesting insights: I've played with DT
> fragments and the overlay configfs patch of Pantelis [1] to have a
> convenient start. Interestingly, I wasn't able to load a fragment that
> followed the format specification for overlays ("Failed to resolve
> tree"). By chance, I got this one working:
>
> /dts-v1/;
> / {
> fragment {
> target-path = "/soc@01c00000";
> __overlay__ {
> #address-cells = <2>;
> #size-cells = <2>;
>
> vpci@0x2000000 {
> compatible = "pci-host-cam-generic";
> device_type = "pci";
> #address-cells = <3>;
> #size-cells = <2>;
> reg = <0 0x2000000 0 0x1000000>;
> ranges =
> <0x02000000 0x00 0x10000000 0x00
> 0x10000000 0x00 0x30000000>;
> };
> };
> };
> };
>
> It successfully makes a BananaPi kernel add a pci host with the
> specified config space and MMIO window.
>
> [ 81.619583] PCI host bridge /soc@01c00000/vpci@0x2000000 ranges:
> [ 81.619610] No bus range found for /soc@01c00000/vpci@0x2000000, using
> [bus 00-ff]
> [ 81.619634] MEM 0x10000000..0x3fffffff -> 0x10000000
> [ 81.620482] pci-host-generic 2000000.vpci: ECAM at [mem
> 0x02000000-0x02ffffff] for [bus 00-ff]
> [ 81.620779] pci-host-generic 2000000.vpci: PCI host bridge to bus 0000:00
> [ 81.620801] pci_bus 0000:00: root bus resource [bus 00-ff]
> [ 81.620814] pci_bus 0000:00: root bus resource [mem 0x10000000-0x3fffffff]
> [ 81.620851] PCI: bus0: Fast back to back transfers enabled
>
> So, no /plugin/ statement, no phandles resolution. This format even
> builds with the in-kernel dtc. Any explanations? Does the code make
> sense (at least it builds without warnings)?
>
> Now I need to back this with some code in Jailhouse.
Meanwhile I got a virtual PCI device recognized by Linux when running
over Jailhouse. However, my hack above doesn't get me to proper
interrupt mapping yet. This is what I was trying with upstream dtc:
/dts-v1/;
/ {
compatible = "lemaker,bananapi", "allwinner,sun7i-a20";
fragment@0 {
target-path = "/soc@01c00000";
__overlay__ {
#address-cells = <2>;
#size-cells = <2>;
vpci@2000000 {
compatible = "pci-host-ecam-generic";
device_type = "pci";
bus-range = <0 0>;
#address-cells = <3>;
#size-cells = <2>;
#interrupt-cells = <1>;
interrupt-map-mask = <0 0 0 7>;
interrupt-map = <0 0 0 1 &gic 0 0 0 123 4>,
<0 0 0 2 &gic 0 0 0 124 4>,
<0 0 0 3 &gic 0 0 0 125 4>,
<0 0 0 4 &gic 0 0 0 126 4>;
reg = <0 0x2000000 0 0x100000>;
ranges =
<0x02000000 0x00 0x10000000 0x00
0x10000000 0x00 0x30000000>;
};
};
};
gic: fragment@1 {
target-path = "/soc@01c00000/interrupt-controller@01c81000";
__overlay__ {
};
};
};
And this is what Linux detects on that PCI bus:
00:0f.0 RAM memory: Red Hat, Inc Inter-VM shared memory
Subsystem: Red Hat, Inc Inter-VM shared memory
Control: I/O- Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
<MAbort- >SERR- <PERR- INTx-
Interrupt: pin A routed to IRQ 17
Region 0: Memory at 10000000 (64-bit, non-prefetchable) [size=256]
Region 4: Memory at 10000100 (64-bit, non-prefetchable) [size=32]
Kernel modules: ivshmem_net
However, registering a handler on IRQ 17 fails (-EINVAL).
With your dtc [2] (dtc -@ -I dts -O dtb -o vpci-bpi.dtb vpci-bpi.dts)
and this fragment, I'm still not able to load the blob:
/dts-v1/;
/plugin/;
/ {
compatible = "lemaker,bananapi", "allwinner,sun7i-a20";
fragment@0 {
target-path = "/soc@01c00000";
__overlay__ {
#address-cells = <2>;
#size-cells = <2>;
vpci@2000000 {
compatible = "pci-host-ecam-generic";
device_type = "pci";
bus-range = <0 0>;
#address-cells = <3>;
#size-cells = <2>;
#interrupt-cells = <1>;
interrupt-map-mask = <0 0 0 7>;
interrupt-map = <0 0 0 1 &gic 0 0 0 123 4>,
<0 0 0 2 &gic 0 0 0 124 4>,
<0 0 0 3 &gic 0 0 0 125 4>,
<0 0 0 4 &gic 0 0 0 126 4>;
reg = <0 0x2000000 0 0x100000>;
ranges =
<0x02000000 0x00 0x10000000 0x00
0x10000000 0x00 0x30000000>;
};
};
};
};
Any suggestions? Any patches I'm missing in upstream to make that work?
Jan
[1]
https://github.com/pantoniou/linux-beagle-track-mainline/commit/160e68ec89eca33e8ed0abb13d52c07c54d7fc10
[2] https://github.com/pantoniou/dtc/tree/dgibson-overlay-panto
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