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

From: Vitor Soares <ivitro@gmail.com>
To: Lucas Stach <l.stach@pengutronix.de>,
	Rob Herring <robh@kernel.org>,
	 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Shawn Guo <shawnguo@kernel.org>,
	 Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>
Cc: Vitor Soares <vitor.soares@toradex.com>,
	devicetree@vger.kernel.org,  imx@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org,
	 linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v1] arm64: dts: imx8mm: fix missing pgc_vpu_* power domain parent
Date: Tue, 09 Apr 2024 17:44:37 +0100	[thread overview]
Message-ID: <bd4d7198e58bd89b46a4c721546f6975b287a5fc.camel@gmail.com> (raw)
In-Reply-To: <fcd6acc268b8642371cf289149b2b1c3e90c7f45.camel@pengutronix.de>

On Tue, 2024-04-09 at 16:36 +0200, Lucas Stach wrote:
> Am Dienstag, dem 09.04.2024 um 14:22 +0100 schrieb Vitor Soares:
> > 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.
> > 
> That's a good hint, the 8MP VPU GPC node additions missed my radar.
> The
> direct dependency there between the GPC domains is equally wrong.
> 
> > 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.
> > 
> The runtime_pm_get_sync() at the start of that function should ensure
> that bus GPC domain aka vpumix is powered up. Can you check if that
> is
> happening?

I checked bc->bus_power_dev->power.runtime_status and it is RPM_ACTIVE.

Am I looking to on the right thing? It is RPM_ACTIVE event before
runtime_pm_get_sync().

> 
> Regards,
> Lucas
> 
> > Do you have an idea how we can address this within blk-ctrl?
> > 
> > Best regards,
> > Vitor