prebuit bitstreams: include dtb files into distribution

[frantony]

Hi @enjoy-digital !

I'm trying to use barebox for booting Linux.
I use prebuilt arty_2020_12_30.zip bitstream for Arty from #164.

I need dtb file for booting linux and barebox. There is neither dtb-file nor even csr.json file attached to the issue #164.

The issue #164 recommends dtb regeneration, but at the moment dtb regeneration for Arty does not work (e.g. 'switches_interrupt' KeyError, see #239).

I used quick-and-dirty hack for litex_json2dts.py to suppress the 'switches_interrupt' KeyError, the generated file linux-on-litex-vexriscv/build/arty/arty.dts contains

  mac0: mac@f0006800 {
        compatible = "litex,liteeth";
        reg = <0xf0006800 0x7c>,
              <0xf0007000 0x0a>,
              <0xb0000000 0x2000>;
        ...
  };

these liteetch base addresses are inapplicable for arty_2020_12_30.zip bitstream. More appropriate addresses are:

  mac0: mac@f0004800 {
          compatible = "litex,liteeth";
          reg = <0xf0004800 0x7c /* base */
                 0xf0004000 0x0a /* mdio_base */
                 0xb0000000 0x2000>; /* buf_base */
        ...
  };

It is not obvious how to regenerate correct dtb for the prebuilt bitstream.

Could you please regenerate prebuit bitstreams, linux stuff and include dtb files into distribution?

[frantony]

I used quick-and-dirty hack for litex_json2dts.py to suppress the 'switches_interrupt' KeyError

Thanks to @MateuszKosmala I can drop quick-and-dirty hack and just use #242

[frantony]

@enjoy-digital

I have just published my version of pre-built images for booting linux with barebox on Arty:
https://github.com/frantony/arty-linux-on-litex-vexriscv-prebuilt

• git lfs is used;
• dtb files are included.

[zoro269]

@frantony
Dear sir
I took a look about your prebuilt image version. Can you show me the steps to build it? Especially the file fw_jump.bin in the folder opensbi.
https://github.com/frantony/arty-linux-on-litex-vexriscv-prebuilt/tree/main/opensbi
Thank you

[enjoy-digital]

The DTB needs to match the exact bitstream/CSR map it was generated with. Regenerating a DTB later from current sources for an older prebuilt bitstream is not reliable, since CSR/peripheral addresses can change between builds.

For current builds:

./make.py --board=arty

generates:

build/arty/arty.dts
build/arty/arty.dtb
images/rv32.dtb

and the Buildroot flow builds the Linux/OpenSBI/rootfs images:

git clone https://github.com/buildroot/buildroot
cd buildroot
make BR2_EXTERNAL=../linux-on-litex-vexriscv/buildroot/ litex_vexriscv_defconfig
make

fw_jump.bin is built by Buildroot/OpenSBI and exposed as images/opensbi.bin by the post-image step.

For future prebuilt bitstream archives, we should indeed include the matching DTB/DTS and CSR files with the bitstream. This is also part of the broader release artifact work discussed in #233.