[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 16:22 schrieb Tomi Valkeinen <tomi.valkeinen at ti.com>:
> 
> On 23/01/18 16:30, Adam Ford wrote:
>> On Tue, Jan 23, 2018 at 7:48 AM, Tomi Valkeinen <tomi.valkeinen at ti.com> wrote:
>>> 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. 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.
>>> 
>> 
>> TI maintains some sort of SGX library on their git repo if I am not
>> mistaken.  If we as a community can get the kernel setup enough and
>> provide TI with patches to make the SGX library work again with omap36
>> and OMAP35 processors, would TI accept patches to their library?  With
>> the changes so far, we're pretty close to getting the kernel the
>> necessary infrastructure to setup/configure the hardware and provide
>> the closed source blobs the necessary hooks to operate.
> 
> TI has SGX kernel driver sources available and SGX library binary blobs
> available for the SoCs TI supports currently (I think that's
> AM5/DRA7/AM4/AM335x).
> 
> git://git.ti.com/graphics/omap5-sgx-ddk-linux.git
> ti-img-sgx/1.14.3699939/k4.9
> 
> git://git.ti.com/graphics/omap5-sgx-ddk-um-linux.git ti-img-sgx/1.14.3699939

Yes, that is what I want this work be based on.

> 
> The community cannot provide patches for the libraries as they are
> closed source.

That is not the goal of the project.

> 
>> Secondly, Nikolaus and Tony have done a great job in trying to get the
>> hwmods and reset stuff working (mostly) for the omap36 and to some
>> extent the am33x.    Would it be possible to get some TI assistance in
>> determining what work is left to re-integrate compatibility into
>> either the DRM of FB drivers?  The SGX drivers appear to have been
>> broken for years and mostly abandoned by TI. I know the OMAP3, OMAP4
>> and AM33 are older architectures, but having TI provide the remaining
>> assistance would go a long way in showing they still care about their
>> products.
> 
> My guess is that the old SGX driver and libraries are quite incompatible
> with the latest ones, so (in my personal opinion) I doubt TI can give
> any support for the old ones.

The key problem is that it is more broken that it needs to be as the
demonstrator patch set shows. There is only one piece missing to make
blobs + kernel driver work on 4.15-rc9 again.

And if we don't do the first step, we will never be able to improve it.

BR,
Nikolaus