Report: FreeBSD on Rpi4 8 GB model

[Robert Crowston]

What works:
- FreeBSD SMP (see below)
- All 8 GB of memory (less video RAM).

What does not work on the 8 GB model (but does work on the 4 GB model):
- xhci (with my driver, there has been a change in the way the firmware is loaded)
- ethernet (genet0 is detected fine, appears to be up, but no packets go over the interface)
- JTAG debugging (urgh)

dmesg: https://dmesgd.nycbug.org/index.cgi?do=view&id=5534

You will need the latest u-boot. The one in pkg doesn't work. I compiled from head: https://github.com/u-boot/u-boot.git

For SMP, you need also need to tell u-boot not to clobber over our processor start up function set up by armstub8-gic.bin.

Edit board/raspberrypi/rpi/Kconfig, set RPI_EFI_NR_SPIN_PAGES to a larger number (I picked 10, probably too big, but it was easier than doing the arithmetic).

$ CROSS_COMPILE=aarch64-none-elf- gmake rpi_4_defconfig
$ CROSS_COMPILE=aarch64-none-elf- gmake

Overwrite the u-boot.bin file on your sdcard with the one just built.

You will also need the latest versions of the pi4 firmware files on your MSDOS partition, bcm2711-rpi-4-b.dtb, fixup4.dat, start4.elf, and the overlays/ directory.