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

[Julien Grall <julien.grall@xxxxxxx>]

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
>
>
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> https://lists.xen.org/xen-users
--
Julien Grall

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