Re: [Xen-users] i2c pass-through in mpsoc

[Jesús Lázaro <jesus.lazaro@xxxxxxx>]

Hi,

Avoiding the dtdev property avoids any error. Now the issue is that, 
although in the devicetree/passthrough section the i2c appears, the 
kernel fails to load any drivers and does not create the /dev/i2c device.
The dom0 kernel has XEN support following 
https://wiki.xenproject.org/wiki/Mainline_Linux_Kernel_Configs
dmesg does not offer any messages regarding issues with the i2c.

What else should I do in order to pass-through the device?

Regards,

Jesús

On 11/10/17 14:20, Julien Grall wrote:
> On 09/10/17 10:33, Jesús Lázaro wrote:
> > Hi,
> Hello,
>
> > I am trying to pass the I2C peripherial in an mpsoc. I have been 
> > following the example to pass the mac but I keep getting the following 
> > error:
> > ----
> > (XEN) XEN_DOMCTL_assign_dt_device: assign "/amba/i2c@ff030000" to dom1 
> > failed (-22)
> > libxl: error: libxl_create.c:1424:libxl__add_dtdevs: 
> > xc_assign_dtdevice failed: -1
> > libxl: error: libxl_create.c:1461:domcreate_attach_devices: unable to 
> > add dtdev devices
> > ----
> This is normal. dtdev will fail when the device passthrough-ed is not 
> behind an SMMU.
> dtdev is only necessary when your device is behind an SMMU. If you know 
> your device will not do DMA, then you can safely drop dtdev=... and 
> continue.
> You might also be interested by the discussion [1] which happened on 
> xen-devel recently regarding the same problem.
> Cheers,
>
> [1] 
> https://lists.xenproject.org/archives/html/xen-devel/2017-10/msg00386.html
> > Attached I send the config file as well as the pass-through device tree.
> >
> > In the main device tree I have modified the I2C to:
> >
> > i2c@ff030000 {
> >    compatible = "cdns,i2c-r1p14", "cdns,i2c-r1p10";
> >    status = "disabled";
> >    xen,passthrough = "1";
> >    interrupt-parent = <0x4>;
> >    interrupts = <0x0 0x12 0x4>;
> >    reg = <0x0 0xff030000 0x0 0x1000>;
> >    #address-cells = <0x1>;
> >    #size-cells = <0x0>;
> >    power-domains = <0x12>;
> >    clocks = <0x3 0x3e>;
> >    clock-frequency = <0x61a80>;
> > };
> >
> > Any hints on where the problem is?
> >
> > Regards,
> >
> > Jesús
> >
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxx
> > https://lists.xen.org/xen-users
--
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Jesús Lázaro Arrotegui Universidad del País Vasco
Tecnología Electrónica
Departamento de Tecnología Electrónica
Escuela de Ingeniería de Bilbao
Email: jesus.lazaro@xxxxxxx
WWW:   det.bi.ehu.eus/~apert
Pl. Ingeniero Torres Quevedo 1     Tel.: 34 - 94 - 601 73 44
48013 BILBAO (SPAIN)                   Fax.: 34 - 94 - 601 39 07
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