linux-kernel - Re: [PATCH v4 08/10] coresight: add a new function in helper

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Message-ID: <CAJ9a7Vi8qpHH2SjmKNjgeY4gdRXY9wnQXhkjN71EcbYSKqayuw@mail.gmail.com>
Date: Tue, 5 Aug 2025 13:30:14 +0100
From: Mike Leach <mike.leach@...aro.org>
To: Jie Gan <jie.gan@....qualcomm.com>
Cc: Suzuki K Poulose <suzuki.poulose@....com>, James Clark <james.clark@...aro.org>, 
	Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Bjorn Andersson <andersson@...nel.org>, Konrad Dybcio <konradybcio@...nel.org>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
	Tingwei Zhang <tingwei.zhang@....qualcomm.com>, Jinlong Mao <jinlong.mao@....qualcomm.com>, 
	coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
	devicetree@...r.kernel.org, Jie Gan <quic_jiegan@...cinc.com>
Subject: Re: [PATCH v4 08/10] coresight: add a new function in helper_ops

Hi,

On Fri, 25 Jul 2025 at 11:08, Jie Gan <jie.gan@....qualcomm.com> wrote:
>
> Add a new function to identifiy whether the byte-cntr function is
> enabled or not in helper_ops.
>
> The byte-cntr's read_ops is expected if the byte-cntr is enabled when
> the user try to read trace data via sysfs node.
>
> Signed-off-by: Jie Gan <jie.gan@....qualcomm.com>
> ---
>  .../hwtracing/coresight/coresight-ctcu-core.c | 35 +++++++++++++++++++
>  include/linux/coresight.h                     |  3 ++
>  2 files changed, 38 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-ctcu-core.c b/drivers/hwtracing/coresight/coresight-ctcu-core.c
> index 8fc08e42187e..dec911980939 100644
> --- a/drivers/hwtracing/coresight/coresight-ctcu-core.c
> +++ b/drivers/hwtracing/coresight/coresight-ctcu-core.c
> @@ -234,9 +234,44 @@ static int ctcu_disable(struct coresight_device *csdev, void *data)
>         return ctcu_set_etr_traceid(csdev, path, false);
>  }
>
> +static bool ctcu_qcom_byte_cntr_in_use(struct coresight_device *csdev,
> +                                      void **data)
> +{
> +       struct ctcu_byte_cntr *byte_cntr_data;
> +       struct coresight_device *helper;
> +       struct ctcu_drvdata *drvdata;
> +       int port;
> +
> +       if (!csdev)
> +               return false;
> +
> +       helper = coresight_get_helper(csdev, CORESIGHT_DEV_SUBTYPE_HELPER_CTCU);
> +       if (!helper)
> +               return false;
> +
> +       port = coresight_get_in_port_dest(csdev, helper);
> +       if (port < 0)
> +               return false;
> +
> +       drvdata = dev_get_drvdata(helper->dev.parent);
> +       /* Something wrong when initialize byte_cntr_read_ops */
> +       if (!drvdata->byte_cntr_read_ops)
> +               return false;
> +
> +       byte_cntr_data = &drvdata->byte_cntr_data[port];
> +       /* Return the pointer of the ctcu_drvdata if byte-cntr has enabled */
> +       if (byte_cntr_data && byte_cntr_data->thresh_val) {
> +               *data = (void *)drvdata->byte_cntr_read_ops;
> +               return true;
> +       }
> +
> +       return false;
> +}
> +
>  static const struct coresight_ops_helper ctcu_helper_ops = {
>         .enable = ctcu_enable,
>         .disable = ctcu_disable,
> +       .qcom_byte_cntr_in_use = ctcu_qcom_byte_cntr_in_use,

These ops structures are for generic functions used throughout the
devices. Do not put this function here.

This is a specific ctcu helper. Make it external to the file and
declare it in coresight-ctcu.h

Mike

>  };
>
>  static const struct coresight_ops ctcu_ops = {
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index 4ac65c68bbf4..b5f052854b08 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -419,11 +419,14 @@ struct coresight_ops_source {
>   *
>   * @enable     : Enable the device
>   * @disable    : Disable the device
> + * @qcom_byte_cntr_in_use:     check whether the byte-cntr is enabled.
>   */
>  struct coresight_ops_helper {
>         int (*enable)(struct coresight_device *csdev, enum cs_mode mode,
>                       void *data);
>         int (*disable)(struct coresight_device *csdev, void *data);
> +       bool (*qcom_byte_cntr_in_use)(struct coresight_device *csdev,
> +                                     void **data);
>  };
>
>
> --
> 2.34.1
>


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