Re: [Freedreno] [PATCH 5/5] drm/msm/mdp5: Use the interconnect API

From: Rob Clark <robdclark@chromium.org>
To: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>,
	"open list:DRM PANEL DRIVERS" <dri-devel@lists.freedesktop.org>,
	freedreno <freedreno@lists.freedesktop.org>,
	Rajesh Yadav <ryadav@codeaurora.org>,
	Boris Brezillon <bbrezillon@kernel.org>,
	David Airlie <airlied@linux.ie>,
	MSM <linux-arm-msm@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Mamta Shukla <mamtashukla555@gmail.com>,
	Sean Paul <seanpaul@chromium.org>,
	Daniel Vetter <daniel@ffwll.ch>, Sean Paul <sean@poorly.run>,
	Georgi Djakov <georgi.djakov@linaro.org>
Subject: Re: [Freedreno] [PATCH 5/5] drm/msm/mdp5: Use the interconnect API
Date: Tue, 18 Jun 2019 14:17:16 -0700	[thread overview]
Message-ID: <CAJs_Fx4ys6CsgfrLHsU_8DKmgNAB6DbF+AQaHOJzwfzMFKj-Tw@mail.gmail.com> (raw)
In-Reply-To: <CAOCk7NoTN6JEo7B=8P=T4C3t_Xr8eQUX=KG9j4N+jXZ8Pw2f4g@mail.gmail.com>

On Tue, Jun 18, 2019 at 1:44 PM Jeffrey Hugo <jeffrey.l.hugo@gmail.com> wrote:
>
> On Tue, Jun 18, 2019 at 2:25 PM Rob Clark <robdclark@gmail.com> wrote:
> >
> > From: Georgi Djakov <georgi.djakov@linaro.org>
> >
> > The interconnect API provides an interface for consumer drivers to
> > express their bandwidth needs in the SoC. This data is aggregated
> > and the on-chip interconnect hardware is configured to the most
> > appropriate power/performance profile.
> >
> > Use the API to configure the interconnects and request bandwidth
> > between DDR and the display hardware (MDP port(s) and rotator
> > downscaler).
> >
> > v2: update the path names to be consistent with dpu, handle the NULL
> >     path case, updated commit msg from Georgi.
> >
> > Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > ---
> >  drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> > index 97179bec8902..eeac429acf40 100644
> > --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> > +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> > @@ -16,6 +16,7 @@
> >   * this program.  If not, see <http://www.gnu.org/licenses/>.
> >   */
> >
> > +#include <linux/interconnect.h>
> >  #include <linux/of_irq.h>
> >
> >  #include "msm_drv.h"
> > @@ -1050,6 +1051,19 @@ static const struct component_ops mdp5_ops = {
> >
> >  static int mdp5_dev_probe(struct platform_device *pdev)
> >  {
> > +       struct icc_path *path0 = of_icc_get(&pdev->dev, "mdp0-mem");
> > +       struct icc_path *path1 = of_icc_get(&pdev->dev, "mdp1-mem");
> > +       struct icc_path *path_rot = of_icc_get(&pdev->dev, "rotator-mem");
> > +
> > +       if (IS_ERR_OR_NULL(path0))
> > +               return PTR_ERR_OR_ZERO(path0);
>
> Umm, am I misunderstanding something?  It seems like of_icc_get()
> returns NULL if the property doesn't exist.  Won't this be backwards
> incompatible?  Existing DTs won't specify the property, and I don't
> believe the property is supported on all targets.  Seems like we'll
> break things by not calling the below component_add() if the
> interconnect is not supported, specified, or the interconnect driver
> is not compiled.

hmm, right, I guess I should test this w/out the dts patch.. probably
should just revert back to the previous logic..

BR,
-R

> > +       icc_set_bw(path0, 0, MBps_to_icc(6400));
> > +
> > +       if (!IS_ERR_OR_NULL(path1))
> > +               icc_set_bw(path1, 0, MBps_to_icc(6400));
> > +       if (!IS_ERR_OR_NULL(path_rot))
> > +               icc_set_bw(path_rot, 0, MBps_to_icc(6400));
> > +
> >         DBG("");
> >         return component_add(&pdev->dev, &mdp5_ops);
> >  }
> > --
> > 2.20.1
> >
> > _______________________________________________
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> > Freedreno@lists.freedesktop.org
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