linux-kernel - Re: [PATCH v3 00/15] Make ETM register accesses consistent with sysreg.h

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Date:   Wed, 23 Mar 2022 10:22:57 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     James Clark <james.clark@....com>
Cc:     suzuki.poulose@....com, coresight@...ts.linaro.org,
        mike.leach@...aro.org, anshuman.khandual@....com,
        leo.yan@...aro.com, Leo Yan <leo.yan@...aro.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 00/15] Make ETM register accesses consistent with
 sysreg.h

On Fri, Mar 04, 2022 at 05:18:57PM +0000, James Clark wrote:
> Changes since v2:
>  * Implement Mike's suggestion of not having _SHIFT and using the existing
>    FIELD_GET and FIELD_PREP methods.
>  * Dropped the change to add the new REG_VAL macro because of the above.
>  * FIELD_PREP could be used in some trivial cases, but in some cases the
>    shift is still required but can be calculated with __bf_shf
>  * Improved the commit messages.
>  * The change is still binary equivalent, but requires an extra step 
>    mentioned at the end of this cover letter.
> 
> Applies to coresight/next 3619ee28488
> Also available at https://gitlab.arm.com/linux-arm/linux-jc/-/tree/james-cs-register-refactor-v3
> 
> To check for binary equivalence follow the same steps in the cover letter
> of v2, but apply the following change to coresight-priv.h. This is because
> the existing version of the macros wrap the expression in a new scope {}
> that flips something in the compiler:
> 
>   #undef FIELD_GET
>   #define FIELD_GET(_mask, _reg) (((_reg) & (_mask)) >> __bf_shf(_mask))
>   #undef FIELD_PREP
>   #define FIELD_PREP(_mask, _val) (((_val) << __bf_shf(_mask)) & (_mask))
> 
> Thanks
> James
> 
> James Clark (15):
>   coresight: etm4x: Cleanup TRCIDR0 register accesses
>   coresight: etm4x: Cleanup TRCIDR2 register accesses
>   coresight: etm4x: Cleanup TRCIDR3 register accesses
>   coresight: etm4x: Cleanup TRCIDR4 register accesses
>   coresight: etm4x: Cleanup TRCIDR5 register accesses
>   coresight: etm4x: Cleanup TRCCONFIGR register accesses
>   coresight: etm4x: Cleanup TRCEVENTCTL1R register accesses
>   coresight: etm4x: Cleanup TRCSTALLCTLR register accesses
>   coresight: etm4x: Cleanup TRCVICTLR register accesses
>   coresight: etm3x: Cleanup ETMTECR1 register accesses
>   coresight: etm4x: Cleanup TRCACATRn register accesses
>   coresight: etm4x: Cleanup TRCSSCCRn and TRCSSCSRn register accesses
>   coresight: etm4x: Cleanup TRCSSPCICRn register accesses
>   coresight: etm4x: Cleanup TRCBBCTLR register accesses
>   coresight: etm4x: Cleanup TRCRSCTLRn register accesses
> 
>  .../coresight/coresight-etm3x-core.c          |   2 +-
>  .../coresight/coresight-etm3x-sysfs.c         |   2 +-
>  .../coresight/coresight-etm4x-core.c          | 136 +++++--------
>  .../coresight/coresight-etm4x-sysfs.c         | 180 +++++++++---------
>  drivers/hwtracing/coresight/coresight-etm4x.h | 122 ++++++++++--
>  5 files changed, 244 insertions(+), 198 deletions(-)

I am done reviewing this set.  I will wait until rc1 or rc2 before moving
forward.  If there are other comments needing a respin then I will wait for the
next revision.  Otherwise I will apply this one after correcting the extra lines
at the end of patch 15.
 
Thanks,
Mathieu

> 
> -- 
> 2.28.0
>