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Linux OS with Custom Programmable Logic

Former Member

Hi,

I have modified the BOOT.bin file on the SD card to use my own FSBL, .bit file, and the u-boot.elf.  The problem with this is that when the default Linux image boots it looks for GPIO which isn't there and as a result it fails.  Is this a problem with the ramdisk or device tree, and if so how could I fix it?  If it's not a problem with these how can I get a Linux OS running on the ARM cores with my own logic design?

Thanks,
Matthew

  • 0

    Hi m.russell,

    I think you will want to look at the device tree first since that offers a description of the platform hardware to the kernel at boot time.

    Reverse compile the device tree back to source and look for something like this for the GPIO hardware:

    gpio@e000a000 {
    compatible = "xlnx,ps7-gpio-1.00.a";
    #gpio-cells = <0x2>;
    reg = <0xe000a000 0x1000>;
    interrupts = <0x0 0x14 0x0>;
    interrupt-parent = <0x1>;
    gpio-controller;
    linux,phandle = <0x8>;
    phandle = <0x8>;
    };

    You may also want to remove other device listings (that are no longer in your Programmable Logic design) while you are exiting the device tree.

    Regards,

    -Kevin

  • 0

    Thanks for your response, I managed to get it working eventually.

    Turns out it wasn't the GPIO itself, the processor was trying to reset an AXI connector which I had replaced.  There seems to be very little documentation from Xilinx about the device tree, which is annoying since it looks quite important.  Fortunately the Tree Generator (http://wiki.xilinx.com/device-tree-generator), whilst not perfect [the Ethernet connection needed fixing], gave me a start.  Do you have any links which would be useful to learn more about how these work?