Bug#1012881: linux: ti soc cpufreq not working
Yu-Tung Chang <mtwget@gmail.com> 于2022年6月23日周四 16:08写道：
>
> Diederik de Haas <didi.debian@cknow.org> 于2022年6月22日周三 22:17写道：
> >
> > Control: tag -1 help
> >
> > On Monday, 20 June 2022 10:09:45 CEST Yu-Tung Chang wrote:
> > > https://lore.kernel.org/linux-arm-kernel/51433693.2@ti.com/T/
> > > https://www.spinics.net/lists/linux-omap/msg138794.html
> > >
> > > Read the link above, ARM_OMAP2PLUS_CPUFREQ is not available for DT
> > > Boot Systems and has been deprecated
> >
> > The 1st link is from 2013 and is quite inconclusive. It talks about changes
> > which should be implemented in a v2 of the patch set.
> > And a *plan* to convert all boards to use DT.
> >
> > The reply to the 2nd link is this:
> > "Hmm I thought we should be only using CONFIG_ARM_TI_CPUFREQ
> > with device tree only booting? What's missing from that to
> > be able to drop ARM_OMAP2PLUS_CPUFREQ?"
> >
> > And then it stops.
> > So while it seems to (somewhat) agree with you, it's still inconclusive.
> >
> > The fact that ARM_OMAP2PLUS_CPUFREQ is still present in 5.19-rc3 shows that
> > the 'conversion process' has not been implemented or at least finished.
> >
> > If you're right and ARM_OMAP2PLUS_CPUFREQ should be deleted, then that should
> > (first) happen upstream.
> >
> > > > Yu-Tung Chang <mtwget@gmail.com> 于2022年6月20日周一 16:02写道：
> > > >
> > > > I am doing further testing, It is now certain that ARM_OMAP2PLUS_CPUFREQ
> > > > is not set in arch/arm/configs/omap2plus_defconfig.
> >
> > That is true. That file has the following line:
> > # CONFIG_ARM_OMAP2PLUS_CPUFREQ is not set
> >
> > It doesn't have ARM_TI_CPUFREQ at all though.
> >
> > > > > On Thursday, 16 June 2022 12:16:46 CEST Yu-Tung Chang wrote:
> > > > > > Package: linux-image-armmp
> > > > > > Version: 5.18.0-1
> > > > > >
> > > > > > enable omap2plus_cpufreq causes ti_cpufreq to not work, and
> > > > > > omap2plus_cpufreq is no longer used in linux.
> >
> > It may be deprecated, according to you, but it is still present in the
> > 5.19-rc3 source code, so "is no longer used in linux" seems to be false.
> >
> > > > > I went looking in (upstream)'s code and what I could find was this:
> > > > >
> > > > > ~/dev/kernel.org/linux$ grep -A4 "config ARM_OMAP2PLUS_CPUFREQ"
> > > > > drivers/cpufreq/Kconfig.arm
> > > > > config ARM_OMAP2PLUS_CPUFREQ
> > > > >
> > > > > bool "TI OMAP2+"
> > > > > depends on ARCH_OMAP2PLUS
> > > > > default ARCH_OMAP2PLUS
> > > > >
> > > > > ~/dev/kernel.org/linux$ grep -A11 "config ARM_TI_CPUFREQ"
> > > > > drivers/cpufreq/Kconfig.arm
> > > > > config ARM_TI_CPUFREQ
> > > > >
> > > > > bool "Texas Instruments CPUFreq support"
> > > > > depends on ARCH_OMAP2PLUS
> > > > > default ARCH_OMAP2PLUS
> > > > > help
> > > > >
> > > > > This driver enables valid OPPs on the running platform
> > > > > based on values contained within the SoC in use.
> > > > > Enable this in order to use the cpufreq-dt driver on all
> > > > > Texas Instruments platforms that provide dt based
> > > > > operating-points-v2 tables with opp-supported-hw
> > > > > data provided. Required for cpufreq support on AM335x,
> > > > > AM437x, DRA7x, and AM57x platforms.
> > > > >
> > > > > I interpreted your bug report as they would be mutually exclusive,
> > > > > but that's far from what _I_ understand of the above Kconfig options.
> >
> > Both modules 'depend on' and 'default to the value of' ARCH_OMAP2PLUS.
> > If those modules indeed prevent each others working, then it would help if
> > those symbols weren't 'bool', but 'tristate' so that they can be build as
> > module and then one can load one and blacklist the other.
> > That is also something that upstream should decide.
> >
> But after "make omap2plus_defconfig", ARM_TI_CPUFREQ in .config will
> be enabled, while ARM_OMAP2PLUS_CPUFREQ will not.
Although I found no explicit dependencies in the source tree.
> > While what you said about omap2plus_defconfig is true, Debian doesn't use that
> > file but has ~ 1 config file for all armhf boards.
> >
> > From ``debian/config/armhf/config`` the ``arch/arm/mach-omap2/Kconfig`` section:
> > # CONFIG_ARCH_OMAP2 is not set
> > CONFIG_ARCH_OMAP3=y
> > CONFIG_ARCH_OMAP4=y
> > CONFIG_SOC_OMAP5=y
> >
> > (salsa commit 12d6bf86b56d72f1f6f7765aa5174c63879ab1f5 may be relevant too)
> >
> > I don't know if it's *possible* to disable ARM_OMAP2PLUS_CPUFREQ in Debian and
> > if so, whether it is *desirable* as it may break other boards (then you have).
> >
> > Furthermore, it seems to me that various upstream work is needed if
> > ARM_OMAP2PLUS_CPUFREQ is indeed deprecated and should be removed.
> >
> > I don't know what's possible and/or desirable (or how to go further from here,
> > so I'm tagging it 'help' so that hopefully one of the actual maintainers takes
> > a look at this and decides how to progress (if so).
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