linux-kernel - Re: [PATCH RFC 1/3] coresight: tmc: add the handle of the event to the path

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Message-ID: <20250922082920.GB516577@e132581.arm.com>
Date: Mon, 22 Sep 2025 09:29:20 +0100
From: Leo Yan <leo.yan@....com>
To: Jie Gan <jie.gan@....qualcomm.com>
Cc: Carl Worth <carl@...amperecomputing.com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Mike Leach <mike.leach@...aro.org>,
	James Clark <james.clark@...aro.org>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Tingwei Zhang <tingwei.zhang@....qualcomm.com>,
	coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC 1/3] coresight: tmc: add the handle of the event to
 the path

On Mon, Sep 22, 2025 at 03:31:39PM +0800, Jie Gan wrote:
> From: Carl Worth <carl@...amperecomputing.com>
> 
> The handle is essential for retrieving the AUX_EVENT of each CPU and is
> required in perf mode. It has been added to the coresight_path so that
> dependent devices can access it from the path when needed.
> 
> Fixes: 080ee83cc361 ("Coresight: Change functions to accept the coresight_path")
> Signed-off-by: Carl Worth <carl@...amperecomputing.com>
> Co-developed-by: Jie Gan <jie.gan@....qualcomm.com>
> Signed-off-by: Jie Gan <jie.gan@....qualcomm.com>
> ---
>  drivers/hwtracing/coresight/coresight-etm-perf.c |  1 +
>  drivers/hwtracing/coresight/coresight-tmc-etr.c  |  3 ++-
>  include/linux/coresight.h                        | 10 ++++++----
>  3 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
> index f677c08233ba..5c256af6e54a 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.c
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
> @@ -520,6 +520,7 @@ static void etm_event_start(struct perf_event *event, int flags)
>  		goto out;
>  
>  	path = etm_event_cpu_path(event_data, cpu);
> +	path->handle = handle;
>  	/* We need a sink, no need to continue without one */
>  	sink = coresight_get_sink(path);
>  	if (WARN_ON_ONCE(!sink))
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> index b07fcdb3fe1a..1040f73f0537 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> @@ -1327,7 +1327,8 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
>  struct etr_buf *tmc_etr_get_buffer(struct coresight_device *csdev,
>  				   enum cs_mode mode, void *data)
>  {
> -	struct perf_output_handle *handle = data;
> +	struct coresight_path *path = data;
> +	struct perf_output_handle *handle = path->handle;
>  	struct etr_perf_buffer *etr_perf;
>  
>  	switch (mode) {
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index 6de59ce8ef8c..4591121ae1d4 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -332,12 +332,14 @@ static struct coresight_dev_list (var) = {				\
>  
>  /**
>   * struct coresight_path - data needed by enable/disable path
> - * @path_list:              path from source to sink.
> - * @trace_id:          trace_id of the whole path.
> + * @path_list:			path from source to sink.
> + * @trace_id:			trace_id of the whole path.
> + * struct perf_output_handle:	handle of the aux_event.

s/struct perf_output_handle/@...dle/

Otherwise, LGTM:

Reviewed-by: Leo Yan <leo.yan@....com>

>   */
>  struct coresight_path {
> -	struct list_head	path_list;
> -	u8			trace_id;
> +	struct list_head		path_list;
> +	u8				trace_id;
> +	struct perf_output_handle	*handle;
>  };
>  
>  enum cs_mode {
> 
> -- 
> 2.34.1
> 
>