Re: [PATCH 1/2] clk: mediatek: mt8365: fix the clock indexes

[Alexandre Mergnat]

On 17/05/2023 10:40, Krzysztof Kozlowski wrote:
> On 17/05/2023 10:28, Alexandre Mergnat wrote:
> > Before the patch [1], the clock probe was done directly in the
> > clk-mt8365 driver. In this probe function, the array which stores the
> > data clocks is sized using the higher defined numbers (*_NR_CLOCK) in
> > the clock lists [2]. Currently, with the patch [1], the specific
> > clk-mt8365 probe function is replaced by the mtk generic one [3], which
> > size the clock data array by adding all the clock descriptor array size
> > provided by the clk-mt8365 driver.
> >
> > Actually, all clock indexes come from the header file [2], that mean, if
> > there are more clock (then more index) in the header file [2] than the
> > number of clock declared in the clock descriptor arrays (which is the
> > case currently), the clock data array will be undersized and then the
> > generic probe function will overflow when it will try to write in
> > "clk_data[CLK_INDEX]". Actually, instead of crashing at boot, the probe
> > function returns an error in the log which looks like:
> > "of_clk_hw_onecell_get: invalid index 135", then this clock isn't
> > enabled.
>
> Please use subject prefixes matching the subsystem. You can get them for
> example with `git log --oneline -- DIRECTORY_OR_FILE` on the directory
> your patch is touching.

I will.

> This is huge ABI break and I don't understand why it is needed. Entire
> description above did not explain me that.

Briefly, clocks with the higher index than the data clock array can't be 
used. I've this issue:
[    0.427054] of_clk_hw_onecell_get: invalid index 135
[    0.429525] of_clk_hw_onecell_get: invalid index 69
[    0.442998] of_clk_hw_onecell_get: invalid index 70

That means CLK_TOP_SSUSB_PHY_CK_EN, CLK_IFR_SSUSB_REF and 
CLK_IFR_SSUSB_XHCI aren't working when I need them. So my USB doesn't work.

> > The simplest way to fix the regression is to remove from the header file
> > [2] the unused clocks.
>
> ??? The simples is to revert the patch, so you won't break the ABI.
>
> > [1]: Commit ffe91cb28f6a ("clk: mediatek: mt8365: Convert to
> >       mtk_clk_simple_{probe,remove}()")
> > [2]: include/dt-bindings/clock/mediatek,mt8365-clk.h
> > [3]: drivers/clk/mediatek/clk-mtk.c
> >
> > Fixes: ffe91cb28f6a ("clk: mediatek: mt8365: Convert to mtk_clk_simple_{probe,remove}()")
> >
> > Signed-off-by: Alexandre Mergnat <amergnat@xxxxxxxxxxxx>
> > ---
> >   include/dt-bindings/clock/mediatek,mt8365-clk.h | 361 ++++++++++++------------
> >   1 file changed, 177 insertions(+), 184 deletions(-)
> >
> > diff --git a/include/dt-bindings/clock/mediatek,mt8365-clk.h b/include/dt-bindings/clock/mediatek,mt8365-clk.h
> > index f9aff1775810..fd59c8bdeb24 100644
> > --- a/include/dt-bindings/clock/mediatek,mt8365-clk.h
> > +++ b/include/dt-bindings/clock/mediatek,mt8365-clk.h
> > @@ -7,147 +7,142 @@
> >   #define _DT_BINDINGS_CLK_MT8365_H
> >   
> >   /* TOPCKGEN */
> > -#define CLK_TOP_CLK_NULL		0> -#define CLK_TOP_I2S0_BCK		1
>
> ...
>
> > +#define CLK_TOP_I2S0_BCK		0
>
> Why? This is really broken. You can remove the defines, but re-shuffling
> everything?!?

I've under-estimated the impact of modifying the defines, I will try to 
find another way to fix the regression in the drivers directly.

Thanks for your review.

> Best regards,
> Krzysztof

--
Regards,
Alexandre