Smatch issues reported for Marvell a38x DDR4

[Tony Dinh]

Hi Andrew,

On Mon, Jul 28, 2025 at 9:25 PM Andrew Goodbody
<andrew.goodbody at linaro.org> wrote:
>
> On 25/07/2025 14:02, Stefan Roese wrote:
> > Hi Andrew,
> >
> > On 24.07.25 18:01, Andrew Goodbody wrote:
> >> Hi Stefan,
> >>
> >> Smatch reports the following issues
> >>
> >> drivers/ddr/marvell/a38x/mv_ddr4_training_calibration.c:1029
> >> mv_ddr4_center_of_mass_calc() warn: unsigned 'd_min' is never less
> >> than zero.
> >> drivers/ddr/marvell/a38x/mv_ddr4_training_calibration.c:2192
> >> mv_ddr4_dm_tuning() warn: unsigned 'reg_val' is never less than zero.
> >> drivers/ddr/marvell/a38x/mv_ddr4_training_calibration.c:2270
> >> mv_ddr4_dm_tuning() warn: unsigned 'reg_val' is never less than zero.
> >> drivers/ddr/marvell/a38x/mv_ddr4_training_calibration.c:662
> >> mv_ddr4_centralization() warn: unsigned 'if_id' is never less than zero.
> >> drivers/ddr/marvell/a38x/mv_ddr4_training_calibration.c:662
> >> mv_ddr4_centralization() warn: we never enter this loop
> >> drivers/ddr/marvell/a38x/mv_ddr4_training_calibration.c:911
> >> mv_ddr4_dqs_reposition() warn: always true condition '(delta >= 0) =>
> >> (0-255 >= 0)'
> >> drivers/ddr/marvell/a38x/mv_ddr4_training_calibration.c:924
> >> mv_ddr4_dqs_reposition() warn: unsigned 'delta' is never less than zero.
> >>
> >> As I have no way to validate the correctness of the code I am not
> >> confident enough to attempt to make the appropriate fixes in this case
> >> as it could affect its operation. Perhaps you would like to take a look?
> >
> > Sure, thanks for all your work on these smatch issues. Really
> > appreciated.
> >
> > But frankly, it's not easy to test anything in this area. I still have
> > access to one board (AFAIK), but minor changes usually don't really
> > make a notable difference in the DDR controller configuration here.
> >
> > My suggestion is to send the patches (or one patch) "as best as you can"
> > to the list for official review. I'll try to review and perhaps someone
> > else with access to such a board will take a look.
> >
> > Thanks,
> > Stefan
>
> OK, patch coming. It was not as invasive as I feared.
>

Please add me to the CC list of your patches. I'll be available (in a
couple weeks) to run regression tests for this Armada 38x DDR4 area.

All the best,
Tony

> Andrew