onboard wireless on rpi4

[greg at unrelenting.technology]

September 6, 2020 9:20 PM, "Mark Millard via freebsd-arm" <freebsd-arm at freebsd.org> wrote:

> On 2020-Sep-6, at 08:20, Robert Crowston via freebsd-arm <freebsd-arm at freebsd.org> wrote:
> 
>> That's interesting: OpenBSD is allowing only the lowest 1 GB of memory for DMA; the documentation I
>> obtained suggests the first 3 GB should be accessible. I am experimenting with this new lower
>> bound.
> 
> https://rpi4-uefi.dev/tag/netbsd reports:
> 
> QUOTE
> NetBSD also is the only OS today to fully support ACPI _DMA descriptors for describing DMA
> translations/constraints. This is very important for supporting Pi and Pi-like platforms via
> straight-up ACPI and without platform DMA quirks.
> END QUOTE

That would be https://reviews.freebsd.org/D25219 for us.. not "full support" though because our bus dma tags are way too weak and inflexible, much worse than NetBSD's :(

The RPi ACPI tables declare a 3GB limit for XHCI, and a 1GB limit for some other devices.

Namely, devices described by
https://github.com/tianocore/edk2-platforms/blob/master/Platform/RaspberryPi/AcpiTables/GpuDevs.asl