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...
Thanks,
Jan
--
Siemens AG, Corporate Technology, CT RDA ITP SES-DE
Corporate Competence Center Embedded Linux
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
