From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: Using DT overlays for adding virtual hardware Date: Tue, 21 Jun 2016 13:22:32 +0200 Message-ID: <57692378.8010909@siemens.com> References: <575828C0.5000008@siemens.com> <20160608151745.GB13355@leverpostej> <28BC1AEC-6A7D-4A97-82F4-5670E884C41D@konsulko.com> <20160608162343.GD13355@leverpostej> <999B1CFF-C204-4C19-AE76-AF9DB54E51E4@konsulko.com> <57584A2C.4030507@siemens.com> <5759069B.4080800@siemens.com> <57691342.2020502@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Return-path: Sender: jailhouse-dev@googlegroups.com In-Reply-To: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Pantelis Antoniou Cc: Mark Rutland , devicetree , Linux Kernel Mailing List , Jailhouse , =?UTF-8?B?TcOlbnMgUnVsbGfDpXJk?= , Antonios Motakis List-Id: devicetree@vger.kernel.org On 2016-06-21 12:24, Pantelis Antoniou wrote: > Hi Jan, >=20 >> On Jun 21, 2016, at 13:13 , Jan Kiszka 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 =3D "/soc@01c00000"; >>> __overlay__ { >>> #address-cells =3D <2>; >>> #size-cells =3D <2>; >>> >>> vpci@0x2000000 { >>> compatible =3D "pci-host-cam-generic"; >>> device_type =3D "pci"; >>> #address-cells =3D <3>; >>> #size-cells =3D <2>; >>> reg =3D <0 0x2000000 0 0x1000000>; >>> ranges =3D >>> <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, u= sing [bus 00-ff] >>> [ 81.619634] MEM 0x10000000..0x3fffffff -> 0x10000000 >>> [ 81.620482] pci-host-generic 2000000.vpci: ECAM at [mem 0x02000000-0= x02ffffff] for [bus 00-ff] >>> [ 81.620779] pci-host-generic 2000000.vpci: PCI host bridge to bus 00= 00:00 >>> [ 81.620801] pci_bus 0000:00: root bus resource [bus 00-ff] >>> [ 81.620814] pci_bus 0000:00: root bus resource [mem 0x10000000-0x3ff= fffff] >>> [ 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 =3D "lemaker,bananapi", "allwinner,sun7i-a20"; >> >> fragment@0 { >> target-path =3D "/soc@01c00000"; >> __overlay__ { >> #address-cells =3D <2>; >> #size-cells =3D <2>; >> >> vpci@2000000 { >> compatible =3D "pci-host-ecam-generic"; >> device_type =3D "pci"; >> bus-range =3D <0 0>; >> #address-cells =3D <3>; >> #size-cells =3D <2>; >> #interrupt-cells =3D <1>; >> interrupt-map-mask =3D <0 0 0 7>; >> interrupt-map =3D <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 =3D <0 0x2000000 0 0x100000>; >> ranges =3D >> <0x02000000 0x00 0x10000000 0x00 0x10000000 0x00 0x30000000>; >> }; >> }; >> }; >> >> gic: fragment@1 { >> target-path =3D "/soc@01c00000/interrupt-controller@01c81000"; >> __overlay__ { >> }; >> }; >> }; >> >=20 > ^ This is not going to work: You need the reference to the real gic not t= he empty fragment > here that has a target there. >=20 > You need to compile with the correct dtc, and you also need to compile th= e base dts > with dtc too, using the -@ flag. You can hack around it by adding somethi= ng like >=20 > __symbols__ { > gic =3D "/soc@01c00000/interrupt-controller@01c81000=E2=80=9D; > }; >=20 > But you really need the __symbols__ node of the base dts generated by the= dtc proper cause > the above is a dirty hack. >=20 OK, re-building the kernel with DTC=3D"/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 --=20 Siemens AG, Corporate Technology, CT RDA ITP SES-DE Corporate Competence Center Embedded Linux --=20 You received this message because you are subscribed to the Google Groups "= Jailhouse" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to jailhouse-dev+unsubscribe@googlegroups.com. For more options, visit https://groups.google.com/d/optout.