linux-kernel - Re: [PATCH 1/2] coresight: tmc: Add enable flag to indicate the status of ETR/ETF

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Date:   Mon, 1 Jun 2020 14:27:36 +0100
From:   Mike Leach <mike.leach@...aro.org>
To:     Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
Cc:     Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-msm@...r.kernel.org,
        Coresight ML <coresight@...ts.linaro.org>,
        Stephen Boyd <swboyd@...omium.org>
Subject: Re: [PATCH 1/2] coresight: tmc: Add enable flag to indicate the
 status of ETR/ETF

Hi,

On Mon, 1 Jun 2020 at 09:02, Sai Prakash Ranjan
<saiprakash.ranjan@...eaurora.org> wrote:
>
> Add a flag to check whether TMC ETR/ETF is enabled or not.
> This is later used in shutdown callback to determine if
> we require to disable ETR/ETF.
>
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
> ---
>  drivers/hwtracing/coresight/coresight-tmc.c | 2 ++
>  drivers/hwtracing/coresight/coresight-tmc.h | 2 ++
>  2 files changed, 4 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
> index 39fba1d16e6e..5a271ebc4585 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc.c
> @@ -62,11 +62,13 @@ void tmc_flush_and_stop(struct tmc_drvdata *drvdata)
>
>  void tmc_enable_hw(struct tmc_drvdata *drvdata)
>  {
> +       drvdata->enable = true;
>         writel_relaxed(TMC_CTL_CAPT_EN, drvdata->base + TMC_CTL);
>  }
>
>  void tmc_disable_hw(struct tmc_drvdata *drvdata)
>  {
> +       drvdata->enable = false;
>         writel_relaxed(0x0, drvdata->base + TMC_CTL);
>  }
>
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
> index 71de978575f3..d156860495c7 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.h
> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
> @@ -184,6 +184,7 @@ struct etr_buf {
>   * @idr_mutex: Access serialisation for idr.
>   * @sysfs_buf: SYSFS buffer for ETR.
>   * @perf_buf:  PERF buffer for ETR.
> + * @enable:    Indicates whether ETR/ETF is enabled.
>   */
>  struct tmc_drvdata {
>         void __iomem            *base;
> @@ -207,6 +208,7 @@ struct tmc_drvdata {
>         struct mutex            idr_mutex;
>         struct etr_buf          *sysfs_buf;
>         struct etr_buf          *perf_buf;
> +       bool                    enable;

Is this flag needed?
For TMC, drvdata->mode indicates if the device is in use.

Regards

Mike
>  };
>
>  struct etr_buf_operations {
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>


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