Raspberry Pi booting and free software

[Danny Milosavljevic]

Hi,

I thought I'd give some summary of the Raspberry Pi situation.

The Raspberry Pi is basically a GPU, the BCM2709 (BCM2836 is BCM2709 with
DRAM on top).

It turned out that there was space for an ARM CPU on the Die, so they put
one there.

The Raspberry Pi boots from the GPU.

The GPU will set up pinmux and system MMU and then eventually release the
ARM CPU from reset.

There's a free software firmware for the GPU in order to enable booting
the CPU, available at https://github.com/christinaa/rpi-open-firmware .

However, it supports only very few things and is not really ready for
normal person use (for example USB *does not work* and neither does
graphics).

I've packaged the required build tools gcc-vc4 and binutils-vc4 some
years back, but it seems that I get the following now:

$ guix build gcc-vc4
guix build: error: gcc-vc4: unknown package

But the following does work:

$ guix build binutils-vc4
/gnu/store/aihynmhjrpbzrh4l2lsjjal95hh038ic-binutils-vc4-2.23.51-0.708acc8

pgpTS1YGX3xnn.pgp
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