linux-kernel - Re: [PATCH v3 14/15] coresight: etm4x: Cleanup TRCBBCTLR register accesses

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Message-ID: <CAJ9a7VgJ-Z0u=u9NwnA_3cxftyXzhTa3QsJVhRUTYfGxiXzaQQ@mail.gmail.com>
Date:   Tue, 12 Apr 2022 11:41:10 +0100
From:   Mike Leach <mike.leach@...aro.org>
To:     James Clark <James.Clark@....com>
Cc:     suzuki.poulose@....com, coresight@...ts.linaro.org,
        Anshuman.Khandual@....com, mathieu.poirier@...aro.org,
        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 14/15] coresight: etm4x: Cleanup TRCBBCTLR register accesses

On Fri, 4 Mar 2022 at 17:19, James Clark <james.clark@....com> wrote:
>
> This is a no-op change for style and consistency and has no effect on
> the binary output by the compiler. In sysreg.h fields are defined as
> the register name followed by the field name and then _MASK. This
> allows for grepping for fields by name rather than using magic numbers.
>
> Signed-off-by: James Clark <james.clark@....com>
> ---
>  drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 4 ++--
>  drivers/hwtracing/coresight/coresight-etm4x.h       | 3 +++
>  2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> index 25f76a656308..3ae6f4432646 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> @@ -707,10 +707,10 @@ static ssize_t bb_ctrl_store(struct device *dev,
>          * individual range comparators. If include then at least 1
>          * range must be selected.
>          */
> -       if ((val & BIT(8)) && (BMVAL(val, 0, 7) == 0))
> +       if ((val & TRCBBCTLR_MODE) && (FIELD_GET(TRCBBCTLR_RANGE_MASK, val) == 0))
>                 return -EINVAL;
>
> -       config->bb_ctrl = val & GENMASK(8, 0);
> +       config->bb_ctrl = val & (TRCBBCTLR_MODE | TRCBBCTLR_RANGE_MASK);
>         return size;
>  }
>  static DEVICE_ATTR_RW(bb_ctrl);
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> index 3b81c104a44b..15704982357f 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> @@ -220,6 +220,9 @@
>
>  #define TRCSSPCICRn_PC_MASK                    GENMASK(7, 0)
>
> +#define TRCBBCTLR_MODE                         BIT(8)
> +#define TRCBBCTLR_RANGE_MASK                   GENMASK(7, 0)
> +
>  /*
>   * System instructions to access ETM registers.
>   * See ETMv4.4 spec ARM IHI0064F section 4.3.6 System instructions
> --
> 2.28.0
>

Reviewed-by: Mike Leach <mike.leach@...aro.org>

-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK