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

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Date:   Wed, 23 Mar 2022 10:15:51 -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 15/15] coresight: etm4x: Cleanup TRCRSCTLRn register
 accesses

On Fri, Mar 04, 2022 at 05:19:12PM +0000, James Clark 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 | 7 +++++--
>  drivers/hwtracing/coresight/coresight-etm4x.h       | 7 +++++++
>  2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> index 3ae6f4432646..6ea8181816fc 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> @@ -1726,8 +1726,11 @@ static ssize_t res_ctrl_store(struct device *dev,
>  	/* For odd idx pair inversal bit is RES0 */
>  	if (idx % 2 != 0)
>  		/* PAIRINV, bit[21] */
> -		val &= ~BIT(21);
> -	config->res_ctrl[idx] = val & GENMASK(21, 0);
> +		val &= ~TRCRSCTLRn_PAIRINV;
> +	config->res_ctrl[idx] = val & (TRCRSCTLRn_PAIRINV |
> +				       TRCRSCTLRn_INV |
> +				       TRCRSCTLRn_GROUP_MASK |
> +				       TRCRSCTLRn_SELECT_MASK);
>  	spin_unlock(&drvdata->spinlock);
>  	return size;
>  }
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> index 15704982357f..2c412841b126 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> @@ -223,6 +223,13 @@
>  #define TRCBBCTLR_MODE				BIT(8)
>  #define TRCBBCTLR_RANGE_MASK			GENMASK(7, 0)
>  
> +#define TRCRSCTLRn_PAIRINV			BIT(21)
> +#define TRCRSCTLRn_INV				BIT(20)
> +#define TRCRSCTLRn_GROUP_MASK			GENMASK(19, 16)
> +#define TRCRSCTLRn_SELECT_MASK			GENMASK(15, 0)
> +
> +
> +

Two extra lines.

>  /*
>   * System instructions to access ETM registers.
>   * See ETMv4.4 spec ARM IHI0064F section 4.3.6 System instructions
> -- 
> 2.28.0
>