Devicetree with no slcr

[doddi76]

Hi,

I am using the latest Vivado2013.2 and trying to build a custom linux image.

I can get the kernel to boot if I use the dts provided in the xilinx github branch but not when I use a dts file generated from the SDK. The SDK doesnt include a slcr section within the devicetree so no clocks are found.

Is this something I have to configure when creating a zynq block within Vivado? Or is it missing from the generation of the devicetree?

Thanks

Doddi

[sorenb]

Which version of the device tree generator are you using. I just did a quick check creating a dts with the latest one (HEAD@a6e440e5a34df51cc5febb4177955bfeb3150bf9) and it does create an SLCR node for me (I used the pre-defined zc706 HW-platform).

[doddi76]

Hi 

Thanks for the response. I am not sure what happened when it didnt generate the SLCR.

Now it seems to be stuck at "Calibrating delay loop..."

I have read that this can bbe due to a mismatch in kernel and device tree but I am using the latest for each HEAD kernel (at the time no differences between tag xilinx-v14.6.02) and Vivado 2013.2.

I am using predefined zc702 hw platform.

[sorenb]

Right, most of the time the reason for this is that the TTC does not find its clock input. Do you see any message indicating something like that during boot?

We did change the clock bindings etc a bit and that causes some trouble if things don't match up. And just to warn you in advance, there are some patches in flight to change them again - hopefully for the last time though.

Anyway, back to your problem: Can you compare the SLCR and TTC nodes in your dts to the ones in zc702/zc706 dts files in the kernel tree you're using?

If you paste/upload your dts I can take a look at it too.

[doddi76]

HI,

the zynq-zc702.dts file is the one provided as part of the kernel which works. The xilinx_vivado.dts is from my Vivado 2013.2 build. I dont see a TTC in the device tree of the vivado build but I am using the preset hardware build.

Many thanks

[sorenb · Accepted solution]

The TTC is currently the only usable clocksource for Zynq. With it missing there is no chance to boot, I think. If the generated dts does not have a TTC node, it's a bug. Please copy the TTC node from one of the kernel dts files into yours and check whether that fixes the issue.

[doddi76]

Thanks for the reply, that seemed to do the trick.

Do I need to raise this as a bug somewhere? and if so how.

Thanks

[sorenb]

We just ran into the same issue independently. The dt-generator will be fixed soon. No action required on your side.