Re: [PATCH v1] arm64: dts: imx8mm: fix missing pgc_vpu_* power domain parent

[Vitor Soares <ivitro@gmail.com>]

Hi Lucas,

Thanks for your feedback.

On Tue, 2024-04-09 at 11:13 +0200, Lucas Stach wrote:
> Hi Vitor,
> 
> Am Dienstag, dem 09.04.2024 um 09:58 +0100 schrieb Vitor Soares:
> > From: Vitor Soares <vitor.soares@toradex.com>
> > 
> > The pgc_vpu_* nodes miss the reference to the power domain parent,
> > leading the system to hang during the resume.
> > 
> This change is not correct. The vpumix domain is controlled through
> the
> imx8mm-vpu-blk-ctrl and must not be directly triggered by the child
> domains in order to guarantee proper power sequencing.
> 
> If the sequencing is incorrect for resume, it needs to be fixed in
> the
> blk-ctrl driver. I'll happily assist if you have any questions about
> this intricate mix between GPC and blk-ctrl hardware/drivers.
 
I'm new into the topic, so I tried to follow same approach as in imx8mp
DT. I also checked the imx8mq DT and it only have one domain for the
VPU in the GPC. It seem blk-ctrl also dependes on pgc_vpu_* to work
properly.

The blk-ctrl driver hangs on imx8m_blk_ctrl_power_on() when access the
ip registers for the soft reset. I tried to power-up the before the
soft reset, but it didn't work.

Do you have an idea how we can address this within blk-ctrl?

Best regards,
Vitor

> 
> Regards,
> Lucas
> 
> > As these PU domains are nested inside the vpumix domain, let's
> > reference
> > it accordingly. After this change, the suspend/resume is working.
> > 
> > Cc: Lucas Stach <l.stach@pengutronix.de>
> > Cc: <stable@vger.kernel.org>
> > Closes:
> > https://lore.kernel.org/all/fccbb040330a706a4f7b34875db1d896a0bf81c8.camel@gmail.com/
> > Fixes: d39d4bb15310 ("arm64: dts: imx8mm: add GPC node")
> > Signed-off-by: Vitor Soares <vitor.soares@toradex.com>
> > ---
> >  arch/arm64/boot/dts/freescale/imx8mm.dtsi | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/freescale/imx8mm.dtsi
> > b/arch/arm64/boot/dts/freescale/imx8mm.dtsi
> > index 8a1b42b94dce..97d0c6d23ad8 100644
> > --- a/arch/arm64/boot/dts/freescale/imx8mm.dtsi
> > +++ b/arch/arm64/boot/dts/freescale/imx8mm.dtsi
> > @@ -739,16 +739,19 @@ pgc_vpumix: power-domain@6 {
> >                                         pgc_vpu_g1: power-domain@7
> > {
> >                                                 #power-domain-cells
> > = <0>;
> >                                                 reg =
> > <IMX8MM_POWER_DOMAIN_VPUG1>;
> > +                                               power-domains =
> > <&pgc_vpumix>;
> >                                         };
> >  
> >                                         pgc_vpu_g2: power-domain@8
> > {
> >                                                 #power-domain-cells
> > = <0>;
> >                                                 reg =
> > <IMX8MM_POWER_DOMAIN_VPUG2>;
> > +                                               power-domains =
> > <&pgc_vpumix>;
> >                                         };
> >  
> >                                         pgc_vpu_h1: power-domain@9
> > {
> >                                                 #power-domain-cells
> > = <0>;
> >                                                 reg =
> > <IMX8MM_POWER_DOMAIN_VPUH1>;
> > +                                               power-domains =
> > <&pgc_vpumix>;
> >                                         };
> >  
> >                                         pgc_dispmix:
> > power-domain@10 {
>