Hi Jan,
> On Jun 21, 2016, at 14:22 , Jan Kiszka <jan.kiszka@xxxxxxxxxxx> wrote:
>
> On 2016-06-21 12:24, Pantelis Antoniou wrote:
>> Hi Jan,
>>
>>> On Jun 21, 2016, at 13:13 , Jan Kiszka <jan.kiszka@xxxxxxxxxxx> wrote:
>>>
>>> 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__ {
>>> };
>>> };
>>> };
>>>
>>
>> ^ This is not going to work: You need the reference to the real gic not the empty fragment
>> here that has a target there.
>>
>> You need to compile with the correct dtc, and you also need to compile the base dts
>> with dtc too, using the -@ flag. You can hack around it by adding something like
>>
>> __symbols__ {
>> gic = "/soc@01c00000/interrupt-controller@01c81000”;
>> };
>>
>> But you really need the __symbols__ node of the base dts generated by the dtc proper cause
>> the above is a dirty hack.
>>
>
> OK, re-building the kernel with DTC="/your/dtc -@", thus building the
> base dtb with symbols, fixes proper overlay format loading.
>
> However, no luck yet with the interrupt topic - maybe a different issue.
> Digging deeper…
>
Remove the gic: fragment and build both the kernel and the overlay with the -@ option.
That’s what makes it not to work.
> Thanks,
> Jan
>
> --
> Siemens AG, Corporate Technology, CT RDA ITP SES-DE
> Corporate Competence Center Embedded Linux
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