[Letux-kernel] Lay common foundation to make PVR/SGX work without hacks on OMAP34xx, OMAP36xx, AM335x and potentially OMAP4, OMAP5

[H. Nikolaus Schaller]

Hi Tomi,

> Am 23.01.2018 um 14:48 schrieb Tomi Valkeinen <tomi.valkeinen at ti.com>:
> 
> Hi,
> 
> On 23/01/18 15:38, H. Nikolaus Schaller wrote:
>> In the end we should have a single, generic SGX driver for all OMAP SoC variants
>> sitting in mainline drivers/gpu/pvr. So the goal is to end the era of out-of
>> tree SGX drivers for a significant portion of OMAP processors.
> 
> I don't think that will ever happen, because there is no open source
> userspace library for SGX. That library is the "real" driver here.

Yes and no... It can be seen as application software for the SGX
and consists of a microkernel and user-space libs to communicate
with it. Both are unfortunately closed source but no kernel components
and need no integration. Just data sent back and forth through open source
drivers.

> At
> least the policy has been (I believe it still is) that you can't have a
> driver in the kernel which can only be used with a closed source
> userspace component.

I see counter-examples, mainly in the WiFi area. There are drivers for
Realtek, Marvell, TI WiFI chips and firmware is separate and required
to make it useful.

Other examples may also exist.

A big question is if we want to wait forever until user-space becomes
open of if we lay a foundation to make it easier to become open (reverse
engineered open-source user-space for example).

BR,
Nikolaus