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 12:13:22 +0200 Message-ID: <57691342.2020502@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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Sender: jailhouse-dev@googlegroups.com In-Reply-To: <5759069B.4080800@siemens.com> 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 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- SERR- ; #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 -- Siemens AG, Corporate Technology, CT RDA ITP SES-DE Corporate Competence Center Embedded Linux