diff mbox series

arm64: dts: renesas: rzg2ul-smarc-som: Drop enabling wdt2

Message ID 20220914134211.199631-1-prabhakar.mahadev-lad.rj@bp.renesas.com (mailing list archive)
State Mainlined
Commit 31989ece707adc453eb9f4f019fdac118f8fee72
Delegated to: Geert Uytterhoeven
Headers show
Series arm64: dts: renesas: rzg2ul-smarc-som: Drop enabling wdt2 | expand

Commit Message

Lad, Prabhakar Sept. 14, 2022, 1:42 p.m. UTC
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

WDT CH2 is specifically to check the operation of Cortex-M33 CPU so
don't enable WDT2 by default.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 arch/arm64/boot/dts/renesas/rzg2ul-smarc-som.dtsi | 5 -----
 1 file changed, 5 deletions(-)

Comments

Geert Uytterhoeven Sept. 18, 2022, 9:04 a.m. UTC | #1
On Wed, Sep 14, 2022 at 3:43 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> WDT CH2 is specifically to check the operation of Cortex-M33 CPU so
> don't enable WDT2 by default.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
i.e. will queue in renesas-devel for v6.1.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Lad, Prabhakar Sept. 19, 2022, 9:47 a.m. UTC | #2
Hi Geert,

Thank you for the review.

On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
>
> On Wed, Sep 14, 2022 at 3:43 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > WDT CH2 is specifically to check the operation of Cortex-M33 CPU so
> > don't enable WDT2 by default.
> >
For consistency I'll drop enabling WDT2 from the RZ/G2L{C} too.

Cheers,
Prabhakar
Biju Das Sept. 19, 2022, 10:06 a.m. UTC | #3
Hi Prabhakar,

> -----Original Message-----
> From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> Sent: 19 September 2022 10:48
> To: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: Magnus Damm <magnus.damm@gmail.com>; Rob Herring
> <robh+dt@kernel.org>; Krzysztof Kozlowski
> <krzysztof.kozlowski+dt@linaro.org>; linux-renesas-
> soc@vger.kernel.org; devicetree@vger.kernel.org; linux-
> kernel@vger.kernel.org; Biju Das <biju.das.jz@bp.renesas.com>;
> Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> enabling wdt2
> 
> Hi Geert,
> 
> Thank you for the review.
> 
> On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven <geert@linux-
> m68k.org> wrote:
> >
> > On Wed, Sep 14, 2022 at 3:43 PM Prabhakar
> <prabhakar.csengg@gmail.com> wrote:
> > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > >
> > > WDT CH2 is specifically to check the operation of Cortex-M33 CPU
> so
> > > don't enable WDT2 by default.
> > >
> For consistency I'll drop enabling WDT2 from the RZ/G2L{C} too.

Does remove unused clocks turn off WDT2 clock during late init??

If that is the case, we should remove entries from clock table as well?

Cheers,
Biju
Geert Uytterhoeven Sept. 19, 2022, 10:10 a.m. UTC | #4
Hi Biju,

On Mon, Sep 19, 2022 at 12:06 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven <geert@linux-
> > m68k.org> wrote:
> > > On Wed, Sep 14, 2022 at 3:43 PM Prabhakar
> > <prabhakar.csengg@gmail.com> wrote:
> > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > >
> > > > WDT CH2 is specifically to check the operation of Cortex-M33 CPU
> > so
> > > > don't enable WDT2 by default.
> > > >
> > For consistency I'll drop enabling WDT2 from the RZ/G2L{C} too.
>
> Does remove unused clocks turn off WDT2 clock during late init??
>
> If that is the case, we should remove entries from clock table as well?

Or add it to *_crit_mod_clks[]?

Note that drivers/clk/renesas/r9a07g043-cpg.c creates wdt2 clocks
and resets, so that should probably be moved inside the #ifdef
CONFIG_ARM64 section.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Biju Das Sept. 19, 2022, 10:15 a.m. UTC | #5
Hi Geert,

Prabhakar Mahadev Lad <prabhakar.mahadev-
> lad.rj@bp.renesas.com>
> Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> enabling wdt2
> 
> Hi Biju,
> 
> On Mon, Sep 19, 2022 at 12:06 PM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> > > On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven <geert@linux-
> > > m68k.org> wrote:
> > > > On Wed, Sep 14, 2022 at 3:43 PM Prabhakar
> > > <prabhakar.csengg@gmail.com> wrote:
> > > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > >
> > > > > WDT CH2 is specifically to check the operation of Cortex-M33
> CPU
> > > so
> > > > > don't enable WDT2 by default.
> > > > >
> > > For consistency I'll drop enabling WDT2 from the RZ/G2L{C} too.
> >
> > Does remove unused clocks turn off WDT2 clock during late init??
> >
> > If that is the case, we should remove entries from clock table as
> well?
> 
> Or add it to *_crit_mod_clks[]?
> 
> Note that drivers/clk/renesas/r9a07g043-cpg.c creates wdt2 clocks and
> resets, so that should probably be moved inside the #ifdef
> CONFIG_ARM64 section.

Yes, both will do, I guess otherwise WDT enabled by Cortex-M33 will be disabled by
CORTEX-A55 during boot.

Cheers,
Biju
Lad, Prabhakar Sept. 19, 2022, 10:44 a.m. UTC | #6
On Mon, Sep 19, 2022 at 11:15 AM Biju Das <biju.das.jz@bp.renesas.com> wrote:
>
> Hi Geert,
>
> Prabhakar Mahadev Lad <prabhakar.mahadev-
> > lad.rj@bp.renesas.com>
> > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> > enabling wdt2
> >
> > Hi Biju,
> >
> > On Mon, Sep 19, 2022 at 12:06 PM Biju Das <biju.das.jz@bp.renesas.com>
> > wrote:
> > > > On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven <geert@linux-
> > > > m68k.org> wrote:
> > > > > On Wed, Sep 14, 2022 at 3:43 PM Prabhakar
> > > > <prabhakar.csengg@gmail.com> wrote:
> > > > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > > >
> > > > > > WDT CH2 is specifically to check the operation of Cortex-M33
> > CPU
> > > > so
> > > > > > don't enable WDT2 by default.
> > > > > >
> > > > For consistency I'll drop enabling WDT2 from the RZ/G2L{C} too.
> > >
> > > Does remove unused clocks turn off WDT2 clock during late init??
> > >
> > > If that is the case, we should remove entries from clock table as
> > well?
> >
> > Or add it to *_crit_mod_clks[]?
> >
> > Note that drivers/clk/renesas/r9a07g043-cpg.c creates wdt2 clocks and
> > resets, so that should probably be moved inside the #ifdef
> > CONFIG_ARM64 section.
>
Yes we dont want it to be listed on RZ/Five.

> Yes, both will do, I guess otherwise WDT enabled by Cortex-M33 will be disabled by
> CORTEX-A55 during boot.
>
Agreed.

Cheers,
Prabhakar
Biju Das Sept. 19, 2022, 10:55 a.m. UTC | #7
> -----Original Message-----
> From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> Sent: 19 September 2022 11:44
> To: Biju Das <biju.das.jz@bp.renesas.com>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>; Magnus Damm
> <magnus.damm@gmail.com>; Rob Herring <robh+dt@kernel.org>; Krzysztof
> Kozlowski <krzysztof.kozlowski+dt@linaro.org>; linux-renesas-
> soc@vger.kernel.org; devicetree@vger.kernel.org; linux-
> kernel@vger.kernel.org; Prabhakar Mahadev Lad <prabhakar.mahadev-
> lad.rj@bp.renesas.com>
> Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> enabling wdt2
> 
> On Mon, Sep 19, 2022 at 11:15 AM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> >
> > Hi Geert,
> >
> > Prabhakar Mahadev Lad <prabhakar.mahadev-
> > > lad.rj@bp.renesas.com>
> > > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> > > enabling wdt2
> > >
> > > Hi Biju,
> > >
> > > On Mon, Sep 19, 2022 at 12:06 PM Biju Das
> > > <biju.das.jz@bp.renesas.com>
> > > wrote:
> > > > > On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven
> > > > > <geert@linux- m68k.org> wrote:
> > > > > > On Wed, Sep 14, 2022 at 3:43 PM Prabhakar
> > > > > <prabhakar.csengg@gmail.com> wrote:
> > > > > > > From: Lad Prabhakar
> > > > > > > <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > > > >
> > > > > > > WDT CH2 is specifically to check the operation of Cortex-
> M33
> > > CPU
> > > > > so
> > > > > > > don't enable WDT2 by default.
> > > > > > >
> > > > > For consistency I'll drop enabling WDT2 from the RZ/G2L{C}
> too.
> > > >
> > > > Does remove unused clocks turn off WDT2 clock during late init??
> > > >
> > > > If that is the case, we should remove entries from clock table
> as
> > > well?
> > >
> > > Or add it to *_crit_mod_clks[]?
> > >
> > > Note that drivers/clk/renesas/r9a07g043-cpg.c creates wdt2 clocks
> > > and resets, so that should probably be moved inside the #ifdef
> > > CONFIG_ARM64 section.
> >
> Yes we dont want it to be listed on RZ/Five.

OK, So this patch [1] will break existing RZ/G2UL till we have clk changes suggested by Geert.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20220919&id=31989ece707adc453eb9f4f019fdac118f8fee72

> 
> > Yes, both will do, I guess otherwise WDT enabled by Cortex-M33 will
> be
> > disabled by
> > CORTEX-A55 during boot.
> >
> Agreed.
> 
> Cheers,
> Prabhakar
Lad, Prabhakar Sept. 19, 2022, 11:04 a.m. UTC | #8
On Mon, Sep 19, 2022 at 11:55 AM Biju Das <biju.das.jz@bp.renesas.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> > Sent: 19 September 2022 11:44
> > To: Biju Das <biju.das.jz@bp.renesas.com>
> > Cc: Geert Uytterhoeven <geert@linux-m68k.org>; Magnus Damm
> > <magnus.damm@gmail.com>; Rob Herring <robh+dt@kernel.org>; Krzysztof
> > Kozlowski <krzysztof.kozlowski+dt@linaro.org>; linux-renesas-
> > soc@vger.kernel.org; devicetree@vger.kernel.org; linux-
> > kernel@vger.kernel.org; Prabhakar Mahadev Lad <prabhakar.mahadev-
> > lad.rj@bp.renesas.com>
> > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> > enabling wdt2
> >
> > On Mon, Sep 19, 2022 at 11:15 AM Biju Das <biju.das.jz@bp.renesas.com>
> > wrote:
> > >
> > > Hi Geert,
> > >
> > > Prabhakar Mahadev Lad <prabhakar.mahadev-
> > > > lad.rj@bp.renesas.com>
> > > > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> > > > enabling wdt2
> > > >
> > > > Hi Biju,
> > > >
> > > > On Mon, Sep 19, 2022 at 12:06 PM Biju Das
> > > > <biju.das.jz@bp.renesas.com>
> > > > wrote:
> > > > > > On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven
> > > > > > <geert@linux- m68k.org> wrote:
> > > > > > > On Wed, Sep 14, 2022 at 3:43 PM Prabhakar
> > > > > > <prabhakar.csengg@gmail.com> wrote:
> > > > > > > > From: Lad Prabhakar
> > > > > > > > <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > > > > >
> > > > > > > > WDT CH2 is specifically to check the operation of Cortex-
> > M33
> > > > CPU
> > > > > > so
> > > > > > > > don't enable WDT2 by default.
> > > > > > > >
> > > > > > For consistency I'll drop enabling WDT2 from the RZ/G2L{C}
> > too.
> > > > >
> > > > > Does remove unused clocks turn off WDT2 clock during late init??
> > > > >
> > > > > If that is the case, we should remove entries from clock table
> > as
> > > > well?
> > > >
> > > > Or add it to *_crit_mod_clks[]?
> > > >
> > > > Note that drivers/clk/renesas/r9a07g043-cpg.c creates wdt2 clocks
> > > > and resets, so that should probably be moved inside the #ifdef
> > > > CONFIG_ARM64 section.
> > >
> > Yes we dont want it to be listed on RZ/Five.
>
> OK, So this patch [1] will break existing RZ/G2UL till we have clk changes suggested by Geert.
>
No it won't, patch [1] just disables enabling wdt2 on A55. Whereas
Geert is suggesting adding wdt2 clk R9A07G043_WDT2_PCLK (and also
R9A07G043_WDT2_CLK?)  to crit_mod_clks so that we dont disable them in
A55 (currently we dont have any scenario where M33 is up with WDT2 and
patch [1] is breaking it). Also Geert's other suggestion was to add
the WDT2 clocks under ARM64 as we dont want them to be visible under
RZ/Five (where wdt2 is not present).

Or is it that I am missing something?

[1] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20220919&id=31989ece707adc453eb9f4f019fdac118f8fee72

Cheers,
Prabhakar
>
> >
> > > Yes, both will do, I guess otherwise WDT enabled by Cortex-M33 will
> > be
> > > disabled by
> > > CORTEX-A55 during boot.
> > >
> > Agreed.
> >
> > Cheers,
> > Prabhakar
Biju Das Sept. 19, 2022, 11:10 a.m. UTC | #9
Hi Prabhakar,

Mahadev Lad <prabhakar.mahadev-
> lad.rj@bp.renesas.com>
> Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> enabling wdt2
> 
> On Mon, Sep 19, 2022 at 11:55 AM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> >
> >
> >
> > > -----Original Message-----
> > > From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> > > Sent: 19 September 2022 11:44
> > > To: Biju Das <biju.das.jz@bp.renesas.com>
> > > Cc: Geert Uytterhoeven <geert@linux-m68k.org>; Magnus Damm
> > > <magnus.damm@gmail.com>; Rob Herring <robh+dt@kernel.org>;
> Krzysztof
> > > Kozlowski <krzysztof.kozlowski+dt@linaro.org>; linux-renesas-
> > > soc@vger.kernel.org; devicetree@vger.kernel.org; linux-
> > > kernel@vger.kernel.org; Prabhakar Mahadev Lad <prabhakar.mahadev-
> > > lad.rj@bp.renesas.com>
> > > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> > > enabling wdt2
> > >
> > > On Mon, Sep 19, 2022 at 11:15 AM Biju Das
> > > <biju.das.jz@bp.renesas.com>
> > > wrote:
> > > >
> > > > Hi Geert,
> > > >
> > > > Prabhakar Mahadev Lad <prabhakar.mahadev-
> > > > > lad.rj@bp.renesas.com>
> > > > > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som:
> Drop
> > > > > enabling wdt2
> > > > >
> > > > > Hi Biju,
> > > > >
> > > > > On Mon, Sep 19, 2022 at 12:06 PM Biju Das
> > > > > <biju.das.jz@bp.renesas.com>
> > > > > wrote:
> > > > > > > On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven
> > > > > > > <geert@linux- m68k.org> wrote:
> > > > > > > > On Wed, Sep 14, 2022 at 3:43 PM Prabhakar
> > > > > > > <prabhakar.csengg@gmail.com> wrote:
> > > > > > > > > From: Lad Prabhakar
> > > > > > > > > <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > > > > > >
> > > > > > > > > WDT CH2 is specifically to check the operation of
> > > > > > > > > Cortex-
> > > M33
> > > > > CPU
> > > > > > > so
> > > > > > > > > don't enable WDT2 by default.
> > > > > > > > >
> > > > > > > For consistency I'll drop enabling WDT2 from the RZ/G2L{C}
> > > too.
> > > > > >
> > > > > > Does remove unused clocks turn off WDT2 clock during late
> init??
> > > > > >
> > > > > > If that is the case, we should remove entries from clock
> table
> > > as
> > > > > well?
> > > > >
> > > > > Or add it to *_crit_mod_clks[]?
> > > > >
> > > > > Note that drivers/clk/renesas/r9a07g043-cpg.c creates wdt2
> > > > > clocks and resets, so that should probably be moved inside the
> > > > > #ifdef
> > > > > CONFIG_ARM64 section.
> > > >
> > > Yes we dont want it to be listed on RZ/Five.
> >
> > OK, So this patch [1] will break existing RZ/G2UL till we have clk
> changes suggested by Geert.
> >
> No it won't, patch [1] just disables enabling wdt2 on A55. Whereas
> Geert is suggesting adding wdt2 clk R9A07G043_WDT2_PCLK (and also
> R9A07G043_WDT2_CLK?)  to crit_mod_clks so that we dont disable them in
> A55 (currently we dont have any scenario where M33 is up with WDT2 and
> patch [1] is breaking it). Also Geert's other suggestion was to add
> the WDT2 clocks under ARM64 as we dont want them to be visible under
> RZ/Five (where wdt2 is not present).
> 
> Or is it that I am missing something?

It all depends upon whether remove unused clocks turn off WDT2 clock during
late boot process. 

I guess, since we have wdt2 entries in clock table, it will turn off WDT clock,
since you have disable it from DT( it becomes unused).

By adding critical clocks, it won't turn off the WDT clock.

Cheers,
Biju

> 
> [1]
> https://jpn01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.
> kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fnext%2Flinux-
> next.git%2Fcommit%2F%3Fh%3Dnext-
> 20220919%26id%3D31989ece707adc453eb9f4f019fdac118f8fee72&amp;data=05%7
> C01%7Cbiju.das.jz%40bp.renesas.com%7C55f37d25d74646611de908da9a2ecfac%
> 7C53d82571da1947e49cb4625a166a4a2a%7C0%7C0%7C637991823087385873%7CUnkn
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwi
> LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=hP2u5NwutD8AhhrOrY6dPvlWW8PkB
> g3skyTMXBJQaWc%3D&amp;reserved=0
> 
> Cheers,
> Prabhakar
> >
> > >
> > > > Yes, both will do, I guess otherwise WDT enabled by Cortex-M33
> > > > will
> > > be
> > > > disabled by
> > > > CORTEX-A55 during boot.
> > > >
> > > Agreed.
> > >
> > > Cheers,
> > > Prabhakar
Geert Uytterhoeven Sept. 19, 2022, 11:37 a.m. UTC | #10
Hi Biju,

On Mon, Sep 19, 2022 at 1:10 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> Mahadev Lad <prabhakar.mahadev-
> > lad.rj@bp.renesas.com>
> > On Mon, Sep 19, 2022 at 11:55 AM Biju Das <biju.das.jz@bp.renesas.com>
> > wrote:
> > > > -----Original Message-----
> > > > From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> > > > Sent: 19 September 2022 11:44
> > > > To: Biju Das <biju.das.jz@bp.renesas.com>
> > > > Cc: Geert Uytterhoeven <geert@linux-m68k.org>; Magnus Damm
> > > > <magnus.damm@gmail.com>; Rob Herring <robh+dt@kernel.org>;
> > Krzysztof
> > > > Kozlowski <krzysztof.kozlowski+dt@linaro.org>; linux-renesas-
> > > > soc@vger.kernel.org; devicetree@vger.kernel.org; linux-
> > > > kernel@vger.kernel.org; Prabhakar Mahadev Lad <prabhakar.mahadev-
> > > > lad.rj@bp.renesas.com>
> > > > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> > > > enabling wdt2
> > > >
> > > > On Mon, Sep 19, 2022 at 11:15 AM Biju Das
> > > > <biju.das.jz@bp.renesas.com>
> > > > wrote:
> > > > > Prabhakar Mahadev Lad <prabhakar.mahadev-
> > > > > > lad.rj@bp.renesas.com>
> > > > > > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som:
> > Drop
> > > > > > enabling wdt2
> > > > > >
> > > > > > Hi Biju,
> > > > > >
> > > > > > On Mon, Sep 19, 2022 at 12:06 PM Biju Das
> > > > > > <biju.das.jz@bp.renesas.com>
> > > > > > wrote:
> > > > > > > > On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven
> > > > > > > > <geert@linux- m68k.org> wrote:
> > > > > > > > > On Wed, Sep 14, 2022 at 3:43 PM Prabhakar
> > > > > > > > <prabhakar.csengg@gmail.com> wrote:
> > > > > > > > > > From: Lad Prabhakar
> > > > > > > > > > <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > > > > > > >
> > > > > > > > > > WDT CH2 is specifically to check the operation of
> > > > > > > > > > Cortex-
> > > > M33
> > > > > > CPU
> > > > > > > > so
> > > > > > > > > > don't enable WDT2 by default.
> > > > > > > > > >
> > > > > > > > For consistency I'll drop enabling WDT2 from the RZ/G2L{C}
> > > > too.
> > > > > > >
> > > > > > > Does remove unused clocks turn off WDT2 clock during late
> > init??
> > > > > > >
> > > > > > > If that is the case, we should remove entries from clock
> > table
> > > > as
> > > > > > well?
> > > > > >
> > > > > > Or add it to *_crit_mod_clks[]?
> > > > > >
> > > > > > Note that drivers/clk/renesas/r9a07g043-cpg.c creates wdt2
> > > > > > clocks and resets, so that should probably be moved inside the
> > > > > > #ifdef
> > > > > > CONFIG_ARM64 section.
> > > > >
> > > > Yes we dont want it to be listed on RZ/Five.
> > >
> > > OK, So this patch [1] will break existing RZ/G2UL till we have clk
> > changes suggested by Geert.
> > >
> > No it won't, patch [1] just disables enabling wdt2 on A55. Whereas
> > Geert is suggesting adding wdt2 clk R9A07G043_WDT2_PCLK (and also
> > R9A07G043_WDT2_CLK?)  to crit_mod_clks so that we dont disable them in
> > A55 (currently we dont have any scenario where M33 is up with WDT2 and
> > patch [1] is breaking it). Also Geert's other suggestion was to add
> > the WDT2 clocks under ARM64 as we dont want them to be visible under
> > RZ/Five (where wdt2 is not present).
> >
> > Or is it that I am missing something?
>
> It all depends upon whether remove unused clocks turn off WDT2 clock during
> late boot process.
>
> I guess, since we have wdt2 entries in clock table, it will turn off WDT clock,
> since you have disable it from DT( it becomes unused).

AFAIU, the WDT cannot trigger when the clock is stopped, so RZ/G2UL
should be fine?

> By adding critical clocks, it won't turn off the WDT clock.

> > [1]
> > https://jpn01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.
> > kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fnext%2Flinux-
> > next.git%2Fcommit%2F%3Fh%3Dnext-
> > 20220919%26id%3D31989ece707adc453eb9f4f019fdac118f8fee72&amp;data=05%7
> > C01%7Cbiju.das.jz%40bp.renesas.com%7C55f37d25d74646611de908da9a2ecfac%
> > 7C53d82571da1947e49cb4625a166a4a2a%7C0%7C0%7C637991823087385873%7CUnkn
> > own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwi
> > LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=hP2u5NwutD8AhhrOrY6dPvlWW8PkB
> > g3skyTMXBJQaWc%3D&amp;reserved=0

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Biju Das Sept. 19, 2022, 11:43 a.m. UTC | #11
Hi Geert,

> Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som: Drop
> enabling wdt2
> 
> Hi Biju,
> 
> On Mon, Sep 19, 2022 at 1:10 PM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> > Mahadev Lad <prabhakar.mahadev-
> > > lad.rj@bp.renesas.com>
> > > On Mon, Sep 19, 2022 at 11:55 AM Biju Das
> > > <biju.das.jz@bp.renesas.com>
> > > wrote:
> > > > > -----Original Message-----
> > > > > From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> > > > > Sent: 19 September 2022 11:44
> > > > > To: Biju Das <biju.das.jz@bp.renesas.com>
> > > > > Cc: Geert Uytterhoeven <geert@linux-m68k.org>; Magnus Damm
> > > > > <magnus.damm@gmail.com>; Rob Herring <robh+dt@kernel.org>;
> > > Krzysztof
> > > > > Kozlowski <krzysztof.kozlowski+dt@linaro.org>; linux-renesas-
> > > > > soc@vger.kernel.org; devicetree@vger.kernel.org; linux-
> > > > > kernel@vger.kernel.org; Prabhakar Mahadev Lad
> > > > > <prabhakar.mahadev- lad.rj@bp.renesas.com>
> > > > > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-som:
> Drop
> > > > > enabling wdt2
> > > > >
> > > > > On Mon, Sep 19, 2022 at 11:15 AM Biju Das
> > > > > <biju.das.jz@bp.renesas.com>
> > > > > wrote:
> > > > > > Prabhakar Mahadev Lad <prabhakar.mahadev-
> > > > > > > lad.rj@bp.renesas.com>
> > > > > > > Subject: Re: [PATCH] arm64: dts: renesas: rzg2ul-smarc-
> som:
> > > Drop
> > > > > > > enabling wdt2
> > > > > > >
> > > > > > > Hi Biju,
> > > > > > >
> > > > > > > On Mon, Sep 19, 2022 at 12:06 PM Biju Das
> > > > > > > <biju.das.jz@bp.renesas.com>
> > > > > > > wrote:
> > > > > > > > > On Sun, Sep 18, 2022 at 10:04 AM Geert Uytterhoeven
> > > > > > > > > <geert@linux- m68k.org> wrote:
> > > > > > > > > > On Wed, Sep 14, 2022 at 3:43 PM Prabhakar
> > > > > > > > > <prabhakar.csengg@gmail.com> wrote:
> > > > > > > > > > > From: Lad Prabhakar
> > > > > > > > > > > <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > > > > > > > >
> > > > > > > > > > > WDT CH2 is specifically to check the operation of
> > > > > > > > > > > Cortex-
> > > > > M33
> > > > > > > CPU
> > > > > > > > > so
> > > > > > > > > > > don't enable WDT2 by default.
> > > > > > > > > > >
> > > > > > > > > For consistency I'll drop enabling WDT2 from the
> > > > > > > > > RZ/G2L{C}
> > > > > too.
> > > > > > > >
> > > > > > > > Does remove unused clocks turn off WDT2 clock during
> late
> > > init??
> > > > > > > >
> > > > > > > > If that is the case, we should remove entries from clock
> > > table
> > > > > as
> > > > > > > well?
> > > > > > >
> > > > > > > Or add it to *_crit_mod_clks[]?
> > > > > > >
> > > > > > > Note that drivers/clk/renesas/r9a07g043-cpg.c creates wdt2
> > > > > > > clocks and resets, so that should probably be moved inside
> > > > > > > the #ifdef
> > > > > > > CONFIG_ARM64 section.
> > > > > >
> > > > > Yes we dont want it to be listed on RZ/Five.
> > > >
> > > > OK, So this patch [1] will break existing RZ/G2UL till we have
> clk
> > > changes suggested by Geert.
> > > >
> > > No it won't, patch [1] just disables enabling wdt2 on A55. Whereas
> > > Geert is suggesting adding wdt2 clk R9A07G043_WDT2_PCLK (and also
> > > R9A07G043_WDT2_CLK?)  to crit_mod_clks so that we dont disable
> them
> > > in
> > > A55 (currently we dont have any scenario where M33 is up with WDT2
> > > and patch [1] is breaking it). Also Geert's other suggestion was
> to
> > > add the WDT2 clocks under ARM64 as we dont want them to be visible
> > > under RZ/Five (where wdt2 is not present).
> > >
> > > Or is it that I am missing something?
> >
> > It all depends upon whether remove unused clocks turn off WDT2 clock
> > during late boot process.
> >
> > I guess, since we have wdt2 entries in clock table, it will turn off
> > WDT clock, since you have disable it from DT( it becomes unused).
> 
> AFAIU, the WDT cannot trigger when the clock is stopped, so RZ/G2UL
> should be fine?

If CA-33 turning on WDT clock (eg:- u-boot loading and booting CA-33) and
Later it will be disabled by CA-55 during late boot, then we will have problem.
Then WDT on CA-33 won't work.

Currently as far as I know, no one is using CA-33 with mainline code, So it is ok.

Cheers,
Biju

> 
> > By adding critical clocks, it won't turn off the WDT clock.
> 
> > > [1]
> > >
> https://jpn01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.
> > > kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fnext%2Flinux-
> > > next.git%2Fcommit%2F%3Fh%3Dnext-
> > >
> 20220919%26id%3D31989ece707adc453eb9f4f019fdac118f8fee72&amp;data=05
> > > %7
> > >
> C01%7Cbiju.das.jz%40bp.renesas.com%7C55f37d25d74646611de908da9a2ecfa
> > > c%
> > >
> 7C53d82571da1947e49cb4625a166a4a2a%7C0%7C0%7C637991823087385873%7CUn
> > > kn
> > >
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haW
> > > wi
> > >
> LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=hP2u5NwutD8AhhrOrY6dPvlWW8P
> > > kB
> > > g3skyTMXBJQaWc%3D&amp;reserved=0
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a
> hacker. But when I'm talking to journalists I just say "programmer" or
> something like that.
>                                 -- Linus Torvalds
diff mbox series

Patch

diff --git a/arch/arm64/boot/dts/renesas/rzg2ul-smarc-som.dtsi b/arch/arm64/boot/dts/renesas/rzg2ul-smarc-som.dtsi
index cf3b3d118ef1..2a0feb53f0dc 100644
--- a/arch/arm64/boot/dts/renesas/rzg2ul-smarc-som.dtsi
+++ b/arch/arm64/boot/dts/renesas/rzg2ul-smarc-som.dtsi
@@ -263,8 +263,3 @@  &wdt0 {
 	status = "okay";
 	timeout-sec = <60>;
 };
-
-&wdt2 {
-	status = "okay";
-	timeout-sec = <60>;
-};