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Device Tree fo Zynq 2014.4 (Linux 3.17)

Former Member

Is there a "known good" device tree compatible with the current Zynq release?  As of 2014.4 they are using Linux 3.17.  The device tree needed for this is very different than the device tree for Linux 3.8 that ships with my MicroZed.

I have things mostly working, but I do have odd issues like my clock seeming to drift a lot.  This makes me wonder if there are settings that I'm missing or have slightly wrong.  Unfortunately, the device tree generator is not good enough to create a fully working tree, and I'm not confident where I need to tweak.

For example, the generator gives lines like:

     operating-points = <666667 1000000 333334 1000000 222223 1000000>;

and the factory provided device tree has lines like:

     xlnx,cpu-1x-clk-freq-hz = <0x69f6bcb>;
     xlnx,cpu-clk-freq-hz = <0x27bc86bf>;

These seem related, yet different.  There are lots of other differences and it hard to sort out which ones matter and which ones are correct.

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    Hi asigint,

    I suggest using the ZedBoard devicetree from the Xilinx 2014.4 release as the starting point.

    http://www.wiki.xilinx.com/Zynq+2014.4+Release

    I tried this on my end and so far this is working well for me.  There were two entries that I found which needed to be modified.

    The first is the memory entry which needs to be expanded to cover the 1GB RAM available on MicroZed:

    memory@0 {
      device_type = "memory";
      reg = < 0x0 0x40000000 >;
    };

    The second entry which needs some attention is the Ethernet phy entry which needs the reg-init string added:

    phy@0 {
      reg = <0x0>;
      marvel,reg-init = <3 16 0xff00 0x1e 3 17 0xfff0 0x00>;
      linux,phandle = <0x4>;
      phandle = <0x4>;
    };

    <EDIT>Although now that I look at it closer, that reg-init string does not appear to have any affect on the Linux kernel that is part of the official Xilinx 2014.4 release so you can probably safely ignore that.</EDIT>

    As for those entry differences that are hard to sort out, I agree that they are confusing but if you focus on the other device entries that are known to be different between boards then that should get you moving forward.

    Regards,

    -Kevin

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    Hi asigint,

    I suggest using the ZedBoard devicetree from the Xilinx 2014.4 release as the starting point.

    http://www.wiki.xilinx.com/Zynq+2014.4+Release

    I tried this on my end and so far this is working well for me.  There were two entries that I found which needed to be modified.

    The first is the memory entry which needs to be expanded to cover the 1GB RAM available on MicroZed:

    memory@0 {
      device_type = "memory";
      reg = < 0x0 0x40000000 >;
    };

    The second entry which needs some attention is the Ethernet phy entry which needs the reg-init string added:

    phy@0 {
      reg = <0x0>;
      marvel,reg-init = <3 16 0xff00 0x1e 3 17 0xfff0 0x00>;
      linux,phandle = <0x4>;
      phandle = <0x4>;
    };

    <EDIT>Although now that I look at it closer, that reg-init string does not appear to have any affect on the Linux kernel that is part of the official Xilinx 2014.4 release so you can probably safely ignore that.</EDIT>

    As for those entry differences that are hard to sort out, I agree that they are confusing but if you focus on the other device entries that are known to be different between boards then that should get you moving forward.

    Regards,

    -Kevin

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