[throwaway2048]

It is a mischaracterization to say they have issues with the firmware, they clearly say they don't have the same objections to firmware running on the peripherals themselves.

The issue here is that the rPI requires driver code running inside OpenBSD that is a closed source blob.

[Bluerise]

I'm sorry, but that is wrong.

The main blobs are being run on the GPU, as bootloaders, even before the actual operating system is loaded. OpenBSD does not need to run _any_ blob itself.

There used to be a 3d graphics driver blob, but afaik that got open sourced. Also, if you don't do 3d, you wouldn't even need it.

[tedunangst]

So, to summarize, if somebody makes a port that doesn't use a blob, all is good. The question seems to be not so much if the blob runs before or after OpenBSD, but whether we would need to distribute it. If it's in the ROM, then this isn't even a question. But if it's something we are expected to write to the flash drive, that's a potential problem. Anyway, the question isn't very interesting given that the magic porting elves haven't yet gifted us with an OpenBSD RPi port.

I don't know exactly what the situation is. Don't care. I have a BeagleboneBlack if I wanted to watch the paint dry doing a build. :)

[LukeShu]

What's OpenBSD's policy on when something needs to be included?

The rPi boot process requires several files to be on a FAT partition on an sd-card: bootcode.bin, fixup.dat, start.elf, config.txt and the OS kernel; the first 3 of which are blobs.

Would those blobs need to be included, or would OpenBSD be fine saying "use your existing boot card, just drop in our kernel", or "go grab these files from https://github.com/raspberrypi/firmware/tree/master/boot when formatting the sd-card."?

[tedunangst]

If the blobs are preexisting that's less of a problem. But it also makes the hardware less interesting.

[Narishma]

The blob runs on a different processor (the GPU), not inside OpenBSD.

[wolfgke]

But the GPU has access to the RAM.

[GauntletWizard]

So does the Hard Disk; see https://en.wikipedia.org/wiki/Direct_memory_access

[zurn]

Depends on how your firmware or OS sets up the memory protection hardware; see https://en.wikipedia.org/wiki/IOMMU

[throwaway7767]

The same applies to the GPU. The rPi does not have an IOMMU, but most platforms OpenBSD supports do not have one either.

That said, based on other discussion here it seems this whole thread is a red-herring and there is no problem with the blobs, it's just that noone has written support for it.

[wolfgke]

If OpenBSD delivers the blob as part of their OS, they take moral responsibility for it (which, for good reasons, they don't want to take). On the other hand, you don't have to deliver a blob to support, say, a hard disk.

[duaneb]

To my understanding, no distribution of a binary blob would be necessary. It is already flashed onto the raspberry pi. The original drivers are open source but not free, but it would be easy to at least get vga working.

[LukeShu]

My knowledge is based on the rPi1, but cursory investigation suggests that this is also true on the rPi2:

There are several blobs that are necessary to be on the sd-card for boot: bootcode.bin, fixup.dat, and start.elf. Any bootable sd-card image for the Pi has them.

What's kind of interesting is that most of what start.elf is is actually an entire OS (ThreadX, I believe), that is running on the VC4 GPU in parallel to the OS on the ARM CPU; and that most of the Linux GPU drivers for it are just shims that send messages saying "hey, ThreadX, would you mind doing this for me?"

[david-given]

My understanding of the boot process is that:

- the VC4 starts up and a ROM starts executing - the ROM loads bootcode.bin into the SRAM - bootcode.bin sets up the DRAM and loads the start.elf and fixup.dat - the start.elf sets up the ARM core and loads the Linux kernel

ARM code only starts executing at the last stage.

The only bit that's actually necessary on the SD card is the bootcode.bin --- everything else is under the control of whatever's in there.

[sklogic]

The open source driver does not run on the VPU.

And the bootloader had been reverse engineered (quite accurately, btw., although all the ISA mnemonics are totally made up). It should be possible now to rebuild it from assembly source.