linux-kernel - Re: [PATCH v3 01/15] coresight: etm4x: Cleanup TRCIDR0 register accesses

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Message-ID: <CAJ9a7Vi+XpJhn8dCWNMNHSoH=rrHc17GdTnGpKjKaFOB9K8AWQ@mail.gmail.com>
Date:   Tue, 12 Apr 2022 09:28:54 +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, leo.yan@...aro.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 01/15] coresight: etm4x: Cleanup TRCIDR0 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>
> ---
>  .../coresight/coresight-etm4x-core.c          | 36 +++++--------------
>  drivers/hwtracing/coresight/coresight-etm4x.h | 13 +++++++
>  2 files changed, 21 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 7f416a12000e..9120390a7613 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -1097,41 +1097,21 @@ static void etm4_init_arch_data(void *info)
>         etmidr0 = etm4x_relaxed_read32(csa, TRCIDR0);
>
>         /* INSTP0, bits[2:1] P0 tracing support field */
> -       if (BMVAL(etmidr0, 1, 2) == 0b11)
> -               drvdata->instrp0 = true;
> -       else
> -               drvdata->instrp0 = false;
> -
> +       drvdata->instrp0 = !!(FIELD_GET(TRCIDR0_INSTP0_MASK, etmidr0) == 0b11);
>         /* TRCBB, bit[5] Branch broadcast tracing support bit */
> -       if (BMVAL(etmidr0, 5, 5))
> -               drvdata->trcbb = true;
> -       else
> -               drvdata->trcbb = false;
> -
> +       drvdata->trcbb = !!(etmidr0 & TRCIDR0_TRCBB);
>         /* TRCCOND, bit[6] Conditional instruction tracing support bit */
> -       if (BMVAL(etmidr0, 6, 6))
> -               drvdata->trccond = true;
> -       else
> -               drvdata->trccond = false;
> -
> +       drvdata->trccond = !!(etmidr0 & TRCIDR0_TRCCOND);
>         /* TRCCCI, bit[7] Cycle counting instruction bit */
> -       if (BMVAL(etmidr0, 7, 7))
> -               drvdata->trccci = true;
> -       else
> -               drvdata->trccci = false;
> -
> +       drvdata->trccci = !!(etmidr0 & TRCIDR0_TRCCCI);
>         /* RETSTACK, bit[9] Return stack bit */
> -       if (BMVAL(etmidr0, 9, 9))
> -               drvdata->retstack = true;
> -       else
> -               drvdata->retstack = false;
> -
> +       drvdata->retstack = !!(etmidr0 & TRCIDR0_RETSTACK);
>         /* NUMEVENT, bits[11:10] Number of events field */
> -       drvdata->nr_event = BMVAL(etmidr0, 10, 11);
> +       drvdata->nr_event = FIELD_GET(TRCIDR0_NUMEVENT_MASK, etmidr0);
>         /* QSUPP, bits[16:15] Q element support field */
> -       drvdata->q_support = BMVAL(etmidr0, 15, 16);
> +       drvdata->q_support = FIELD_GET(TRCIDR0_QSUPP_MASK, etmidr0);
>         /* TSSIZE, bits[28:24] Global timestamp size field */
> -       drvdata->ts_size = BMVAL(etmidr0, 24, 28);
> +       drvdata->ts_size = FIELD_GET(TRCIDR0_TSSIZE_MASK, etmidr0);
>
>         /* maximum size of resources */
>         etmidr2 = etm4x_relaxed_read32(csa, TRCIDR2);
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> index 3c4d69b096ca..300741fbc0de 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> @@ -130,6 +130,19 @@
>
>  #define TRCRSR_TA                      BIT(12)
>
> +/*
> + * Bit positions of registers that are defined above, in the sysreg.h style
> + * of _MASK for multi bit fields and BIT() for single bits.
> + */
> +#define TRCIDR0_INSTP0_MASK                    GENMASK(2, 1)
> +#define TRCIDR0_TRCBB                          BIT(5)
> +#define TRCIDR0_TRCCOND                                BIT(6)
> +#define TRCIDR0_TRCCCI                         BIT(7)
> +#define TRCIDR0_RETSTACK                       BIT(9)
> +#define TRCIDR0_NUMEVENT_MASK                  GENMASK(11, 10)
> +#define TRCIDR0_QSUPP_MASK                     GENMASK(16, 15)
> +#define TRCIDR0_TSSIZE_MASK                    GENMASK(28, 24)
> +
>  /*
>   * System instructions to access ETM registers.
>   * See ETMv4.4 spec ARM IHI0064F section 4.3.6 System instructions
> --
> 2.28.0
>
> _______________________________________________
> CoreSight mailing list -- coresight@...ts.linaro.org
> To unsubscribe send an email to coresight-leave@...ts.linaro.org

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

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