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

[Tony Lindgren]

* H. Nikolaus Schaller <hns at goldelico.com> [190212 20:00]:
> > Am 11.02.2019 um 16:18 schrieb Tony Lindgren <tony at atomide.com>:
> > And just to add some notes I've already mentioned before, there's nothing
> > stopping us from having a generic mainline kernel module for slow 2d
> > acceleration based on what we already have for sgx540 in
> > drivers/gpu/drm/gma500/psb_drv.c.
> > 
> > If anybody is interested in that, grep for PSB_RSGX32 and PSB_WSGX32
> > in the mainline kernel tree. That way at least the generic parts for
> > regulators, clocking, and interrupt handling could be upstreamed. I
> > think only the SoC specific wrapper hardware is different, the SGX
> > code should be generic.
> 
> Interesting. But to me it seems to be completely orthogonal to the
> SGX DDK. And since it is an Intel GMA, there is probably much different
> clock and register integration into an Intel processor than for OMAP or
> other SoC.

To me it seems just the wrapper IP is different. If you look at
drivers/gpu/drm/gma500/accel_2d.c it seems to be only accessing
the sgx registers based on a quick glance. So it's already quite
generic.

Also there's the rule of thumb requirement Tomi mentioned earlier.
That is the driver must provide actual hardware acceleration and
not just a way of enabling out-of-tree binary blobs if I recall.

So from that point of view a generic sgx 2d acceleration driver
to drivers/gpu is probably a better place to start upstreaming
rather than try to stuff vendor specific hacks on top of
imagination hacks into drivers staging :)

Sure it won't help with the 3d parts except we then have the
clocks and interrupts etc handled in a generic way. And then
the 3d parts in theory should become generic too and with much
less of a diffstat..

Regards,

Tony