Re: [PATCH v14 06/10] Coresight: Change to read the trace ID from coresight_path

[Jie Gan <quic_jiegan@xxxxxxxxxxx>]

On 2/26/2025 12:13 PM, Jie Gan wrote:
> The source device can directly read the trace ID from the coresight_path
> which result in etm_read_alloc_trace_id and etm4_read_alloc_trace_id being
> deleted.
>
> Signed-off-by: Jie Gan <quic_jiegan@xxxxxxxxxxx>

Correct tags:
Co-developed-by: James Clark <james.clark@xxxxxxxxxx>
Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
Signed-off-by: Jie Gan <quic_jiegan@xxxxxxxxxxx>

> ---
>   drivers/hwtracing/coresight/coresight-dummy.c |  2 +-
>   .../hwtracing/coresight/coresight-etm-perf.c  |  8 +--
>   drivers/hwtracing/coresight/coresight-etm.h   |  1 -
>   .../coresight/coresight-etm3x-core.c          | 54 +++----------------
>   .../coresight/coresight-etm4x-core.c          | 54 +++----------------
>   drivers/hwtracing/coresight/coresight-etm4x.h |  1 -
>   drivers/hwtracing/coresight/coresight-stm.c   |  2 +-
>   drivers/hwtracing/coresight/coresight-sysfs.c |  7 +--
>   drivers/hwtracing/coresight/coresight-tpdm.c  |  2 +-
>   include/linux/coresight.h                     |  2 +-
>   10 files changed, 25 insertions(+), 108 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-dummy.c b/drivers/hwtracing/coresight/coresight-dummy.c
> index b5692ba358c1..aaa92b5081e3 100644
> --- a/drivers/hwtracing/coresight/coresight-dummy.c
> +++ b/drivers/hwtracing/coresight/coresight-dummy.c
> @@ -24,7 +24,7 @@ DEFINE_CORESIGHT_DEVLIST(sink_devs, "dummy_sink");
>   
>   static int dummy_source_enable(struct coresight_device *csdev,
>   			       struct perf_event *event, enum cs_mode mode,
> -			       __maybe_unused struct coresight_trace_id_map *id_map)
> +			       __maybe_unused struct coresight_path *path)
>   {
>   	if (!coresight_take_mode(csdev, mode))
>   		return -EBUSY;
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
> index 134290ab622e..300305d67a1d 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.c
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
> @@ -461,7 +461,6 @@ static void etm_event_start(struct perf_event *event, int flags)
>   	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
>   	struct coresight_path *path;
>   	u64 hw_id;
> -	u8 trace_id;
>   
>   	if (!csdev)
>   		goto fail;
> @@ -504,8 +503,7 @@ static void etm_event_start(struct perf_event *event, int flags)
>   		goto fail_end_stop;
>   
>   	/* Finally enable the tracer */
> -	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF,
> -				      &sink->perf_sink_id_map))
> +	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF, path))
>   		goto fail_disable_path;
>   
>   	/*
> @@ -515,13 +513,11 @@ static void etm_event_start(struct perf_event *event, int flags)
>   	if (!cpumask_test_cpu(cpu, &event_data->aux_hwid_done)) {
>   		cpumask_set_cpu(cpu, &event_data->aux_hwid_done);
>   
> -		trace_id = coresight_trace_id_read_cpu_id_map(cpu, &sink->perf_sink_id_map);
> -
>   		hw_id = FIELD_PREP(CS_AUX_HW_ID_MAJOR_VERSION_MASK,
>   				CS_AUX_HW_ID_MAJOR_VERSION);
>   		hw_id |= FIELD_PREP(CS_AUX_HW_ID_MINOR_VERSION_MASK,
>   				CS_AUX_HW_ID_MINOR_VERSION);
> -		hw_id |= FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK, trace_id);
> +		hw_id |= FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK, path->trace_id);
>   		hw_id |= FIELD_PREP(CS_AUX_HW_ID_SINK_ID_MASK, coresight_get_sink_id(sink));
>   
>   		perf_report_aux_output_id(event, hw_id);
> diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
> index e02c3ea972c9..171f1384f7c0 100644
> --- a/drivers/hwtracing/coresight/coresight-etm.h
> +++ b/drivers/hwtracing/coresight/coresight-etm.h
> @@ -284,6 +284,5 @@ extern const struct attribute_group *coresight_etm_groups[];
>   void etm_set_default(struct etm_config *config);
>   void etm_config_trace_mode(struct etm_config *config);
>   struct etm_config *get_etm_config(struct etm_drvdata *drvdata);
> -int etm_read_alloc_trace_id(struct etm_drvdata *drvdata);
>   void etm_release_trace_id(struct etm_drvdata *drvdata);
>   #endif
> diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> index c1dda4bc4a2f..8927bfaf3af2 100644
> --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> @@ -455,26 +455,6 @@ static int etm_cpu_id(struct coresight_device *csdev)
>   	return drvdata->cpu;
>   }
>   
> -int etm_read_alloc_trace_id(struct etm_drvdata *drvdata)
> -{
> -	int trace_id;
> -
> -	/*
> -	 * This will allocate a trace ID to the cpu,
> -	 * or return the one currently allocated.
> -	 *
> -	 * trace id function has its own lock
> -	 */
> -	trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu);
> -	if (IS_VALID_CS_TRACE_ID(trace_id))
> -		drvdata->traceid = (u8)trace_id;
> -	else
> -		dev_err(&drvdata->csdev->dev,
> -			"Failed to allocate trace ID for %s on CPU%d\n",
> -			dev_name(&drvdata->csdev->dev), drvdata->cpu);
> -	return trace_id;
> -}
> -
>   void etm_release_trace_id(struct etm_drvdata *drvdata)
>   {
>   	coresight_trace_id_put_cpu_id(drvdata->cpu);
> @@ -482,38 +462,22 @@ void etm_release_trace_id(struct etm_drvdata *drvdata)
>   
>   static int etm_enable_perf(struct coresight_device *csdev,
>   			   struct perf_event *event,
> -			   struct coresight_trace_id_map *id_map)
> +			   struct coresight_path *path)
>   {
>   	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> -	int trace_id;
>   
>   	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
>   		return -EINVAL;
>   
>   	/* Configure the tracer based on the session's specifics */
>   	etm_parse_event_config(drvdata, event);
> -
> -	/*
> -	 * perf allocates cpu ids as part of _setup_aux() - device needs to use
> -	 * the allocated ID. This reads the current version without allocation.
> -	 *
> -	 * This does not use the trace id lock to prevent lock_dep issues
> -	 * with perf locks - we know the ID cannot change until perf shuts down
> -	 * the session
> -	 */
> -	trace_id = coresight_trace_id_read_cpu_id_map(drvdata->cpu, id_map);
> -	if (!IS_VALID_CS_TRACE_ID(trace_id)) {
> -		dev_err(&drvdata->csdev->dev, "Failed to set trace ID for %s on CPU%d\n",
> -			dev_name(&drvdata->csdev->dev), drvdata->cpu);
> -		return -EINVAL;
> -	}
> -	drvdata->traceid = (u8)trace_id;
> +	drvdata->traceid = path->trace_id;
>   
>   	/* And enable it */
>   	return etm_enable_hw(drvdata);
>   }
>   
> -static int etm_enable_sysfs(struct coresight_device *csdev)
> +static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path)
>   {
>   	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>   	struct etm_enable_arg arg = { };
> @@ -521,10 +485,7 @@ static int etm_enable_sysfs(struct coresight_device *csdev)
>   
>   	spin_lock(&drvdata->spinlock);
>   
> -	/* sysfs needs to allocate and set a trace ID */
> -	ret = etm_read_alloc_trace_id(drvdata);
> -	if (ret < 0)
> -		goto unlock_enable_sysfs;
> +	drvdata->traceid = path->trace_id;
>   
>   	/*
>   	 * Configure the ETM only if the CPU is online.  If it isn't online
> @@ -545,7 +506,6 @@ static int etm_enable_sysfs(struct coresight_device *csdev)
>   	if (ret)
>   		etm_release_trace_id(drvdata);
>   
> -unlock_enable_sysfs:
>   	spin_unlock(&drvdata->spinlock);
>   
>   	if (!ret)
> @@ -554,7 +514,7 @@ static int etm_enable_sysfs(struct coresight_device *csdev)
>   }
>   
>   static int etm_enable(struct coresight_device *csdev, struct perf_event *event,
> -		      enum cs_mode mode, struct coresight_trace_id_map *id_map)
> +		      enum cs_mode mode, struct coresight_path *path)
>   {
>   	int ret;
>   	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> @@ -566,10 +526,10 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event,
>   
>   	switch (mode) {
>   	case CS_MODE_SYSFS:
> -		ret = etm_enable_sysfs(csdev);
> +		ret = etm_enable_sysfs(csdev, path);
>   		break;
>   	case CS_MODE_PERF:
> -		ret = etm_enable_perf(csdev, event, id_map);
> +		ret = etm_enable_perf(csdev, event, path);
>   		break;
>   	default:
>   		ret = -EINVAL;
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index cfd116b87460..1ed957f5df61 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -233,25 +233,6 @@ static int etm4_cpu_id(struct coresight_device *csdev)
>   	return drvdata->cpu;
>   }
>   
> -int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata)
> -{
> -	int trace_id;
> -
> -	/*
> -	 * This will allocate a trace ID to the cpu,
> -	 * or return the one currently allocated.
> -	 * The trace id function has its own lock
> -	 */
> -	trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu);
> -	if (IS_VALID_CS_TRACE_ID(trace_id))
> -		drvdata->trcid = (u8)trace_id;
> -	else
> -		dev_err(&drvdata->csdev->dev,
> -			"Failed to allocate trace ID for %s on CPU%d\n",
> -			dev_name(&drvdata->csdev->dev), drvdata->cpu);
> -	return trace_id;
> -}
> -
>   void etm4_release_trace_id(struct etmv4_drvdata *drvdata)
>   {
>   	coresight_trace_id_put_cpu_id(drvdata->cpu);
> @@ -788,9 +769,9 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
>   
>   static int etm4_enable_perf(struct coresight_device *csdev,
>   			    struct perf_event *event,
> -			    struct coresight_trace_id_map *id_map)
> +			    struct coresight_path *path)
>   {
> -	int ret = 0, trace_id;
> +	int ret = 0;
>   	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>   
>   	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id())) {
> @@ -803,22 +784,7 @@ static int etm4_enable_perf(struct coresight_device *csdev,
>   	if (ret)
>   		goto out;
>   
> -	/*
> -	 * perf allocates cpu ids as part of _setup_aux() - device needs to use
> -	 * the allocated ID. This reads the current version without allocation.
> -	 *
> -	 * This does not use the trace id lock to prevent lock_dep issues
> -	 * with perf locks - we know the ID cannot change until perf shuts down
> -	 * the session
> -	 */
> -	trace_id = coresight_trace_id_read_cpu_id_map(drvdata->cpu, id_map);
> -	if (!IS_VALID_CS_TRACE_ID(trace_id)) {
> -		dev_err(&drvdata->csdev->dev, "Failed to set trace ID for %s on CPU%d\n",
> -			dev_name(&drvdata->csdev->dev), drvdata->cpu);
> -		ret = -EINVAL;
> -		goto out;
> -	}
> -	drvdata->trcid = (u8)trace_id;
> +	drvdata->trcid = path->trace_id;
>   
>   	/* And enable it */
>   	ret = etm4_enable_hw(drvdata);
> @@ -827,7 +793,7 @@ static int etm4_enable_perf(struct coresight_device *csdev,
>   	return ret;
>   }
>   
> -static int etm4_enable_sysfs(struct coresight_device *csdev)
> +static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path)
>   {
>   	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>   	struct etm4_enable_arg arg = { };
> @@ -844,10 +810,7 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
>   
>   	spin_lock(&drvdata->spinlock);
>   
> -	/* sysfs needs to read and allocate a trace ID */
> -	ret = etm4_read_alloc_trace_id(drvdata);
> -	if (ret < 0)
> -		goto unlock_sysfs_enable;
> +	drvdata->trcid = path->trace_id;
>   
>   	/*
>   	 * Executing etm4_enable_hw on the cpu whose ETM is being enabled
> @@ -864,7 +827,6 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
>   	if (ret)
>   		etm4_release_trace_id(drvdata);
>   
> -unlock_sysfs_enable:
>   	spin_unlock(&drvdata->spinlock);
>   
>   	if (!ret)
> @@ -873,7 +835,7 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
>   }
>   
>   static int etm4_enable(struct coresight_device *csdev, struct perf_event *event,
> -		       enum cs_mode mode, struct coresight_trace_id_map *id_map)
> +		       enum cs_mode mode, struct coresight_path *path)
>   {
>   	int ret;
>   
> @@ -884,10 +846,10 @@ static int etm4_enable(struct coresight_device *csdev, struct perf_event *event,
>   
>   	switch (mode) {
>   	case CS_MODE_SYSFS:
> -		ret = etm4_enable_sysfs(csdev);
> +		ret = etm4_enable_sysfs(csdev, path);
>   		break;
>   	case CS_MODE_PERF:
> -		ret = etm4_enable_perf(csdev, event, id_map);
> +		ret = etm4_enable_perf(csdev, event, path);
>   		break;
>   	default:
>   		ret = -EINVAL;
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
> index 1119762b5cec..2b92de17b5a2 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.h
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.h
> @@ -1066,6 +1066,5 @@ static inline bool etm4x_is_ete(struct etmv4_drvdata *drvdata)
>   	return drvdata->arch >= ETM_ARCH_ETE;
>   }
>   
> -int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata);
>   void etm4_release_trace_id(struct etmv4_drvdata *drvdata);
>   #endif
> diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
> index aca25b5e3be2..26f9339f38b9 100644
> --- a/drivers/hwtracing/coresight/coresight-stm.c
> +++ b/drivers/hwtracing/coresight/coresight-stm.c
> @@ -195,7 +195,7 @@ static void stm_enable_hw(struct stm_drvdata *drvdata)
>   
>   static int stm_enable(struct coresight_device *csdev, struct perf_event *event,
>   		      enum cs_mode mode,
> -		      __maybe_unused struct coresight_trace_id_map *trace_id)
> +		      __maybe_unused struct coresight_path *path)
>   {
>   	struct stm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>   
> diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
> index d03751bf3d8a..3ac5b52413a6 100644
> --- a/drivers/hwtracing/coresight/coresight-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
> @@ -53,7 +53,8 @@ ssize_t coresight_simple_show32(struct device *_dev,
>   EXPORT_SYMBOL_GPL(coresight_simple_show32);
>   
>   static int coresight_enable_source_sysfs(struct coresight_device *csdev,
> -					 enum cs_mode mode, void *data)
> +					 enum cs_mode mode,
> +					 struct coresight_path *path)
>   {
>   	int ret;
>   
> @@ -64,7 +65,7 @@ static int coresight_enable_source_sysfs(struct coresight_device *csdev,
>   	 */
>   	lockdep_assert_held(&coresight_mutex);
>   	if (coresight_get_mode(csdev) != CS_MODE_SYSFS) {
> -		ret = source_ops(csdev)->enable(csdev, data, mode, NULL);
> +		ret = source_ops(csdev)->enable(csdev, NULL, mode, path);
>   		if (ret)
>   			return ret;
>   	}
> @@ -217,7 +218,7 @@ int coresight_enable_sysfs(struct coresight_device *csdev)
>   	if (ret)
>   		goto err_path;
>   
> -	ret = coresight_enable_source_sysfs(csdev, CS_MODE_SYSFS, NULL);
> +	ret = coresight_enable_source_sysfs(csdev, CS_MODE_SYSFS, path);
>   	if (ret)
>   		goto err_source;
>   
> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
> index c38f9701665e..fec49a537658 100644
> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
> @@ -440,7 +440,7 @@ static void __tpdm_enable(struct tpdm_drvdata *drvdata)
>   
>   static int tpdm_enable(struct coresight_device *csdev, struct perf_event *event,
>   		       enum cs_mode mode,
> -		       __maybe_unused struct coresight_trace_id_map *id_map)
> +		       __maybe_unused struct coresight_path *path)
>   {
>   	struct tpdm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>   
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index 00404ba19352..8f76e7c45b38 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -400,7 +400,7 @@ struct coresight_ops_link {
>   struct coresight_ops_source {
>   	int (*cpu_id)(struct coresight_device *csdev);
>   	int (*enable)(struct coresight_device *csdev, struct perf_event *event,
> -		      enum cs_mode mode, struct coresight_trace_id_map *id_map);
> +		      enum cs_mode mode, struct coresight_path *path);
>   	void (*disable)(struct coresight_device *csdev,
>   			struct perf_event *event);
>   };