linux-kernel - Re: [PATCH v5 12/14] cpufreq: Add Kryo CPU scaling driver

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Date:   Fri, 4 May 2018 12:27:09 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     ilialin@...eaurora.org
Cc:     mturquette@...libre.com, sboyd@...nel.org, robh@...nel.org,
        mark.rutland@....com, rjw@...ysocki.net, lgirdwood@...il.com,
        broonie@...nel.org, andy.gross@...aro.org, david.brown@...aro.org,
        catalin.marinas@....com, will.deacon@....com,
        linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, rnayak@...eaurora.org,
        amit.kucheria@...aro.org, nicolas.dechesne@...aro.org,
        celster@...eaurora.org, tfinkel@...eaurora.org
Subject: Re: [PATCH v5 12/14] cpufreq: Add Kryo CPU scaling driver

On 04-05-18, 09:44, ilialin@...eaurora.org wrote:
> 
> 
> > -----Original Message-----
> > From: Viresh Kumar <viresh.kumar@...aro.org>
> > Sent: Friday, May 4, 2018 09:08
> > To: Ilia Lin <ilialin@...eaurora.org>
> > Cc: mturquette@...libre.com; sboyd@...nel.org; robh@...nel.org;
> > mark.rutland@....com; rjw@...ysocki.net; lgirdwood@...il.com;
> > broonie@...nel.org; andy.gross@...aro.org; david.brown@...aro.org;
> > catalin.marinas@....com; will.deacon@....com; linux-clk@...r.kernel.org;
> > devicetree@...r.kernel.org; linux-kernel@...r.kernel.org; linux-
> > pm@...r.kernel.org; linux-arm-msm@...r.kernel.org; linux-
> > soc@...r.kernel.org; linux-arm-kernel@...ts.infradead.org;
> > rnayak@...eaurora.org; amit.kucheria@...aro.org;
> > nicolas.dechesne@...aro.org; celster@...eaurora.org;
> > tfinkel@...eaurora.org
> > Subject: Re: [PATCH v5 12/14] cpufreq: Add Kryo CPU scaling driver
> > 
> > On 03-05-18, 14:52, Ilia Lin wrote:
> > > In Certain QCOM SoCs like apq8096 and msm8996 that have KRYO
> > > processors, the CPU ferequencies subset and voltage value of each OPP
> > > varies based on the silicon variant in use. Qualcomm Process Voltage
> > > Scaling Tables defines the voltage and frequency value based on the
> > > msm-id in SMEM and speedbin blown in the efuse combination.
> > > The qcom-cpufreq-kryo driver reads the msm-id and efuse value from the
> > > SoC to provide the OPP framework with required information.
> > > This is used to determine the voltage and frequency value for each OPP
> > > of
> > > operating-points-v2 table when it is parsed by the OPP framework.
> > >
> > > Signed-off-by: Ilia Lin <ilialin@...eaurora.org>
> > > ---
> > >  drivers/cpufreq/Kconfig.arm          |  11 +++
> > >  drivers/cpufreq/Makefile             |   1 +
> > >  drivers/cpufreq/cpufreq-dt-platdev.c |   3 +
> > >  drivers/cpufreq/qcom-cpufreq-kryo.c  | 153
> > > +++++++++++++++++++++++++++++++++++
> > >  4 files changed, 168 insertions(+)
> > >  create mode 100644 drivers/cpufreq/qcom-cpufreq-kryo.c
> > >
> > > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> > > index de55c7d..f9da18c 100644
> > > --- a/drivers/cpufreq/Kconfig.arm
> > > +++ b/drivers/cpufreq/Kconfig.arm
> > > @@ -124,6 +124,17 @@ config ARM_OMAP2PLUS_CPUFREQ
> > >  	depends on ARCH_OMAP2PLUS
> > >  	default ARCH_OMAP2PLUS
> > >
> > > +config ARM_QCOM_CPUFREQ_KRYO
> > > +	tristate "Qualcomm Technologies, Inc. Kryo based CPUFreq"
> > 
> > I don't see any reply to Sricharan's query on this being tristate.
> 
> Why shouldn't we leave possibility to compile the cpufreq-dt built-in, and
> the qcom-cpufreq-kryo module?

I was not saying this is incorrect, all I am saying is that you never
replied to a comment from one of the reviewers.

And I don't see a reason why this should be a tristate really.
cpufreq-dt is already capable of being a module, all your driver does
is that it creates the cpufreq-dt platform device after setting the
OPP hw properties..

Over that, have you ever tried inserting, then removing and inserting
the driver module again? I feel it will fail.

The reason is that you never provided an exit routine which can get
rid of the platform device created in the first place.

> > > +	depends on QCOM_QFPROM
> > > +	depends on QCOM_SMEM
> > > +	select PM_OPP
> > > +	help
> > > +	  This adds the CPUFreq driver for
> > > +	  Qualcomm Technologies, Inc. Kryo SoC based boards.
> > > +
> > > +	  If in doubt, say N.
> > > +
> > >  config ARM_S3C_CPUFREQ
> > >  	bool
> > >  	help
> > > diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index
> > > 8d24ade..fb4a2ec 100644
> > > --- a/drivers/cpufreq/Makefile
> > > +++ b/drivers/cpufreq/Makefile
> > > @@ -65,6 +65,7 @@ obj-$(CONFIG_MACH_MVEBU_V7)		+=
> > mvebu-cpufreq.o
> > >  obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ)	+= omap-cpufreq.o
> > >  obj-$(CONFIG_ARM_PXA2xx_CPUFREQ)	+= pxa2xx-cpufreq.o
> > >  obj-$(CONFIG_PXA3xx)			+= pxa3xx-cpufreq.o
> > > +obj-$(CONFIG_ARM_QCOM_CPUFREQ_KRYO)	+= qcom-cpufreq-
> > kryo.o
> > >  obj-$(CONFIG_ARM_S3C2410_CPUFREQ)	+= s3c2410-cpufreq.o
> > >  obj-$(CONFIG_ARM_S3C2412_CPUFREQ)	+= s3c2412-cpufreq.o
> > >  obj-$(CONFIG_ARM_S3C2416_CPUFREQ)	+= s3c2416-cpufreq.o
> > > diff --git a/drivers/cpufreq/cpufreq-dt-platdev.c
> > > b/drivers/cpufreq/cpufreq-dt-platdev.c
> > > index 3b585e4..77d6ab8 100644
> > > --- a/drivers/cpufreq/cpufreq-dt-platdev.c
> > > +++ b/drivers/cpufreq/cpufreq-dt-platdev.c
> > > @@ -118,6 +118,9 @@
> > >
> > >  	{ .compatible = "nvidia,tegra124", },
> > >
> > > +	{ .compatible = "qcom,apq8096", },
> > > +	{ .compatible = "qcom,msm8996", },
> > > +
> > >  	{ .compatible = "st,stih407", },
> > >  	{ .compatible = "st,stih410", },
> > >
> > > diff --git a/drivers/cpufreq/qcom-cpufreq-kryo.c
> > > b/drivers/cpufreq/qcom-cpufreq-kryo.c
> > > new file mode 100644
> > > index 0000000..32371cc
> > > --- /dev/null
> > > +++ b/drivers/cpufreq/qcom-cpufreq-kryo.c
> > > @@ -0,0 +1,153 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/* Copyright (c) 2018, The Linux Foundation. All rights reserved.
> > 
> > Incorrect multi line comment.
> 
> This was done as per Bjorn's instruction.

You haven't followed him correctly.

What he asked for is:

// SPDX...
/*
 * XXXX
 */

What you have done is:

// SPDX...
/* XXXX
 */
 
-- 
viresh