Re: [PATCH RFC v6 2/9] PM / devfreq: Add generic imx bus scaling driver

From: Marco Felsch <m.felsch@pengutronix.de>
To: Leonard Crestez <leonard.crestez@nxp.com>
Cc: "Angus Ainslie" <angus@akkea.ca>, "Jacky Bai" <ping.bai@nxp.com>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Artur Świgoń" <a.swigon@partner.samsung.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	"Viresh Kumar" <viresh.kumar@linaro.org>,
	"Michael Turquette" <mturquette@baylibre.com>,
	"Alexandre Bailon" <abailon@baylibre.com>,
	"Matthias Kaehlcke" <mka@chromium.org>,
	"Abel Vesa" <abel.vesa@nxp.com>,
	"Anson Huang" <anson.huang@nxp.com>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Chanwoo Choi" <cw00.choi@samsung.com>,
	"MyungJoo Ham" <myungjoo.ham@samsung.com>,
	dl-linux-imx <linux-imx@nxp.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Martin Kepplinger" <martink@posteo.de>,
	"Silvano Di Ninno" <silvano.dininno@nxp.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"Aisheng Dong" <aisheng.dong@nxp.com>,
	"Saravana Kannan" <saravanak@google.com>,
	"Stephen Boyd" <sboyd@kernel.org>,
	"Kyungmin Park" <kyungmin.park@samsung.com>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	"Fabio Estevam" <fabio.estevam@nxp.com>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Georgi Djakov" <georgi.djakov@linaro.org>
Subject: Re: [PATCH RFC v6 2/9] PM / devfreq: Add generic imx bus scaling driver
Date: Wed, 20 Nov 2019 16:29:22 +0100	[thread overview]
Message-ID: <20191120152922.vaisxxyizqgjsnld@pengutronix.de> (raw)
In-Reply-To: <VI1PR04MB70233920AC838AD88E1ECC26EE4F0@VI1PR04MB7023.eurprd04.prod.outlook.com>

Hi Leonard,

On 19-11-20 15:04, Leonard Crestez wrote:
> On 20.11.2019 16:08, Angus Ainslie wrote:
> > Hi Leonard,
> > 
> > On 2019-11-14 12:09, Leonard Crestez wrote:
> >> Add initial support for dynamic frequency switching on pieces of the
> >> imx
> >> interconnect fabric.
> >>
> >> All this driver does is set a clk rate based on an opp table, it does
> >> not map register areas.
> >>
> > 
> > Is this working with mainline ATF or does it still need to be used with
> > your modified ATF code ?
> 
> This series doesn't perform SMC calls, that's done by the imx8m-ddrc 
> driver: https://patchwork.kernel.org/cover/11244283/
> 
> This particular patch allows switching NOC frequency but that's just 
> clk_set_rate.
> 
> DDRC frequency switching requires the imx branch of ATF (v2.0 + ~200 
> patches) otherwise you will get probe failures. Source for imx atf is 
> published here: https://source.codeaurora.org/external/imx/imx-atf/
> 
> For your particular 8mq B0 case slightly different setpoints are used 
> and the fix is not in any public release yet so you need this:
> 
> https://github.com/cdleonard/arm-trusted-firmware/commits/imx_2.0.y_busfreq
> 
> Is "mainline ATF" an important criteria for Purism?

Sorry for jumping in here. Just asking myself if the nxp-atf is required
for a mainline kernel for the imx8mq devices?

Thanks,
Marco

> --
> Regards,
> Leonard
> 
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> 

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