[PATCH v9 00/23] drm/rockchip: RK356x VOP2 support

[Sascha Hauer]

On Wed, Apr 06, 2022 at 10:02:59AM +0800, Andy Yan wrote:
> Hi:
> 
> On 4/5/22 17:37, Sascha Hauer wrote:
> > On Sat, Apr 02, 2022 at 09:37:17AM +0800, Andy Yan wrote:
> > > Hi Sacha:
> > > 
> > > On 4/1/22 20:52, Sascha Hauer wrote:
> > > > -- 
> > > > >From cbc03073623a7180243331ac24c3afaf9dec7522 Mon Sep 17 00:00:00 2001
> > > > From: Sascha Hauer<s.hauer at pengutronix.de>
> > > > Date: Fri, 1 Apr 2022 14:48:49 +0200
> > > > Subject: [PATCH] fixup! drm: rockchip: Add VOP2 driver
> > > > 
> > > > ---
> > > >    drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 14 ++++++++++++++
> > > >    1 file changed, 14 insertions(+)
> > > > 
> > > > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> > > > index 7dba7b9b63dc6..1421bf2f133f1 100644
> > > > --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> > > > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> > > > @@ -2287,6 +2287,20 @@ static int vop2_create_crtc(struct vop2 *vop2)
> > > >    			}
> > > >    		}
> > > > +		if (vop2->data->soc_id == 3566) {
> > > > +			/*
> > > > +			 * On RK3566 these windows don't have an independent
> > > > +			 * framebuffer. They share the framebuffer with smart0,
> > > > +			 * esmart0 and cluster0 respectively.
> > > > +			 */
> > > > +			switch (win->data->phys_id) {
> > > > +			case ROCKCHIP_VOP2_SMART1:
> > > > +			case ROCKCHIP_VOP2_ESMART1:
> > > > +			case ROCKCHIP_VOP2_CLUSTER1:
> > > > +				continue;
> > > > +			}
> > > 
> > > Think about this , there maybe other upcoming vop2 base soc, they may only
> > > have
> > > 
> > > mirror window Smart1 Esmart1, or Smart1, Esmart1, Esmart2, Cluster1.
> > > 
> > > I think this should add WIN_FEATURE at the platform description file
> > > rockchip_vop2_reg.c, then
> > > 
> > > check the FEATURE to decide whether the driver should give this window a
> > > special treatment.
> > > 
> > > this can make one code run for different soc with different platform
> > > description. or we should add
> > > 
> > > the same code logic for different soc again and again.
> > You mean like done in the downstream Kernel? Here indeed we have a
> > WIN_FEATURE_MIRROR flag added to the platform description. This is then
> > evaluated with:
> > 
> > static bool vop2_is_mirror_win(struct vop2_win *win)
> > {
> >          return soc_is_rk3566() && (win->feature & WIN_FEATURE_MIRROR);
> > }
> > 
> > So a flag is added and afterwards its evaluation is SoC specific. That
> > doesn't help at all and only obfuscates things.
> > 
> > Besides, experience shows that you can't predict a good abstraction for
> 
> This is not a  predict,  this is an IP feature, so it will appeared on
> upcoming SOC.
> 
> We have rk3588 with 8 windows(4 Cluster + 4 Esmart, no Smart window), and
> 
> also have a entry level soc which only have 4 windows, they both have this
> feature.

Same as with the other discussion: Please let's solve this once we are
there.
For now my addition is the easiest way out. Once other SoCs shall be
supported we can re-evaluate that and find better suitable ways for SoC
abstractions. This may result in just your suggestion (in which case you
can say told-you-so) or completely different.

Sascha

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