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[PATCH v8 2/8] coresight: core: add a new API to retrieve the helper device

Jie Gan posted 8 patches 2 months ago
There is a newer version of this series
[PATCH v8 2/8] coresight: core: add a new API to retrieve the helper device
Posted by Jie Gan 2 months ago 
Retrieving the helper device of the specific coresight device based on
its helper_subtype because a single coresight device may has multiple types
of the helper devices.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
---
 drivers/hwtracing/coresight/coresight-core.c | 35 ++++++++++++++++++++++++++++
 drivers/hwtracing/coresight/coresight-priv.h |  2 ++
 2 files changed, 37 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 0e8448784c62..667883ccb4b7 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -585,6 +585,41 @@ struct coresight_device *coresight_get_sink(struct coresight_path *path)
 }
 EXPORT_SYMBOL_GPL(coresight_get_sink);
 
+/**
+ * coresight_get_helper: find the helper device of the assigned csdev.
+ *
+ * @csdev: The csdev the helper device is conntected to.
+ * @type:  helper_subtype of the expected helper device.
+ *
+ * Retrieve the helper device for the specific csdev based on its
+ * helper_subtype.
+ *
+ * Return: the helper's csdev upon success or NULL for fail.
+ */
+struct coresight_device *coresight_get_helper(struct coresight_device *csdev,
+					      enum coresight_dev_subtype_helper subtype)
+{
+	int i;
+	struct coresight_device *helper;
+
+	/* protect the connections */
+	mutex_lock(&coresight_mutex);
+	for (i = 0; i < csdev->pdata->nr_outconns; ++i) {
+		helper = csdev->pdata->out_conns[i]->dest_dev;
+		if (!helper || !coresight_is_helper(helper))
+			continue;
+
+		if (helper->subtype.helper_subtype == subtype) {
+			mutex_unlock(&coresight_mutex);
+			return helper;
+		}
+	}
+	mutex_unlock(&coresight_mutex);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(coresight_get_helper);
+
 /**
  * coresight_get_in_port: Find the input port number at @csdev where a @remote
  * device is connected to.
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index cbf80b83e5ce..8e39a4dc7256 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -157,6 +157,8 @@ void coresight_path_assign_trace_id(struct coresight_path *path,
 				   enum cs_mode mode);
 int coresight_get_in_port(struct coresight_device *csdev,
 			  struct coresight_device *remote);
+struct coresight_device *coresight_get_helper(struct coresight_device *csdev,
+					      enum coresight_dev_subtype_helper subtype);
 
 #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM3X)
 int etm_readl_cp14(u32 off, unsigned int *val);

-- 
2.34.1
Re: [PATCH v8 2/8] coresight: core: add a new API to retrieve the helper device
Posted by Suzuki K Poulose 1 month, 3 weeks ago 
On 11/12/2025 06:10, Jie Gan wrote:
> Retrieving the helper device of the specific coresight device based on
> its helper_subtype because a single coresight device may has multiple types
> of the helper devices.
> 
> Reviewed-by: Mike Leach <mike.leach@linaro.org>
> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
> ---
>   drivers/hwtracing/coresight/coresight-core.c | 35 ++++++++++++++++++++++++++++
>   drivers/hwtracing/coresight/coresight-priv.h |  2 ++
>   2 files changed, 37 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index 0e8448784c62..667883ccb4b7 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -585,6 +585,41 @@ struct coresight_device *coresight_get_sink(struct coresight_path *path)
>   }
>   EXPORT_SYMBOL_GPL(coresight_get_sink);
>   
> +/**
> + * coresight_get_helper: find the helper device of the assigned csdev.
> + *
> + * @csdev: The csdev the helper device is conntected to.
> + * @type:  helper_subtype of the expected helper device.
> + *
> + * Retrieve the helper device for the specific csdev based on its
> + * helper_subtype.
> + *
> + * Return: the helper's csdev upon success or NULL for fail.
> + */
> +struct coresight_device *coresight_get_helper(struct coresight_device *csdev,
> +					      enum coresight_dev_subtype_helper subtype)

We have almost a similar function in coresight-core.c :

coresight_find_output_type(pdata, type, subtype).

Please could we reuse that, instead of adding similar funcitons ?

Please be careful about the mutex.

Suzuki

> +{
> +	int i;
> +	struct coresight_device *helper;
> +
> +	/* protect the connections */
> +	mutex_lock(&coresight_mutex);
> +	for (i = 0; i < csdev->pdata->nr_outconns; ++i) {
> +		helper = csdev->pdata->out_conns[i]->dest_dev;
> +		if (!helper || !coresight_is_helper(helper))
> +			continue;
> +
> +		if (helper->subtype.helper_subtype == subtype) {
> +			mutex_unlock(&coresight_mutex);
> +			return helper;
> +		}
> +	}
> +	mutex_unlock(&coresight_mutex);
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(coresight_get_helper);
> +
>   /**
>    * coresight_get_in_port: Find the input port number at @csdev where a @remote
>    * device is connected to.
> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> index cbf80b83e5ce..8e39a4dc7256 100644
> --- a/drivers/hwtracing/coresight/coresight-priv.h
> +++ b/drivers/hwtracing/coresight/coresight-priv.h
> @@ -157,6 +157,8 @@ void coresight_path_assign_trace_id(struct coresight_path *path,
>   				   enum cs_mode mode);
>   int coresight_get_in_port(struct coresight_device *csdev,
>   			  struct coresight_device *remote);
> +struct coresight_device *coresight_get_helper(struct coresight_device *csdev,
> +					      enum coresight_dev_subtype_helper subtype);
>   
>   #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM3X)
>   int etm_readl_cp14(u32 off, unsigned int *val);
>
Re: [PATCH v8 2/8] coresight: core: add a new API to retrieve the helper device
Posted by Jie Gan 1 month, 3 weeks ago 

On 12/19/2025 1:50 AM, Suzuki K Poulose wrote:
> On 11/12/2025 06:10, Jie Gan wrote:
>> Retrieving the helper device of the specific coresight device based on
>> its helper_subtype because a single coresight device may has multiple 
>> types
>> of the helper devices.
>>
>> Reviewed-by: Mike Leach <mike.leach@linaro.org>
>> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-core.c | 35 ++++++++++++++++++ 
>> ++++++++++
>>   drivers/hwtracing/coresight/coresight-priv.h |  2 ++
>>   2 files changed, 37 insertions(+)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/ 
>> hwtracing/coresight/coresight-core.c
>> index 0e8448784c62..667883ccb4b7 100644
>> --- a/drivers/hwtracing/coresight/coresight-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>> @@ -585,6 +585,41 @@ struct coresight_device 
>> *coresight_get_sink(struct coresight_path *path)
>>   }
>>   EXPORT_SYMBOL_GPL(coresight_get_sink);
>> +/**
>> + * coresight_get_helper: find the helper device of the assigned csdev.
>> + *
>> + * @csdev: The csdev the helper device is conntected to.
>> + * @type:  helper_subtype of the expected helper device.
>> + *
>> + * Retrieve the helper device for the specific csdev based on its
>> + * helper_subtype.
>> + *
>> + * Return: the helper's csdev upon success or NULL for fail.
>> + */
>> +struct coresight_device *coresight_get_helper(struct coresight_device 
>> *csdev,
>> +                          enum coresight_dev_subtype_helper subtype)
> 
> We have almost a similar function in coresight-core.c :
> 
> coresight_find_output_type(pdata, type, subtype).
> 
> Please could we reuse that, instead of adding similar funcitons ?
> 
> Please be careful about the mutex.
> 

Thanks for the suggestion. I reviewed coresight_find_output_type, and I 
believe we can reuse it to retrieve the CTCU device.

Thanks,
Jie

> Suzuki
> 
>> +{
>> +    int i;
>> +    struct coresight_device *helper;
>> +
>> +    /* protect the connections */
>> +    mutex_lock(&coresight_mutex);
>> +    for (i = 0; i < csdev->pdata->nr_outconns; ++i) {
>> +        helper = csdev->pdata->out_conns[i]->dest_dev;
>> +        if (!helper || !coresight_is_helper(helper))
>> +            continue;
>> +
>> +        if (helper->subtype.helper_subtype == subtype) {
>> +            mutex_unlock(&coresight_mutex);
>> +            return helper;
>> +        }
>> +    }
>> +    mutex_unlock(&coresight_mutex);
>> +
>> +    return NULL;
>> +}
>> +EXPORT_SYMBOL_GPL(coresight_get_helper);
>> +
>>   /**
>>    * coresight_get_in_port: Find the input port number at @csdev where 
>> a @remote
>>    * device is connected to.
>> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/ 
>> hwtracing/coresight/coresight-priv.h
>> index cbf80b83e5ce..8e39a4dc7256 100644
>> --- a/drivers/hwtracing/coresight/coresight-priv.h
>> +++ b/drivers/hwtracing/coresight/coresight-priv.h
>> @@ -157,6 +157,8 @@ void coresight_path_assign_trace_id(struct 
>> coresight_path *path,
>>                      enum cs_mode mode);
>>   int coresight_get_in_port(struct coresight_device *csdev,
>>                 struct coresight_device *remote);
>> +struct coresight_device *coresight_get_helper(struct coresight_device 
>> *csdev,
>> +                          enum coresight_dev_subtype_helper subtype);
>>   #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM3X)
>>   int etm_readl_cp14(u32 off, unsigned int *val);
>>
>
Re: [PATCH v8 2/8] coresight: core: add a new API to retrieve the helper device
Posted by kernel test robot 1 month, 4 weeks ago 
Hi Jie,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 47b7b5e32bb7264b51b89186043e1ada4090b558]

url:    https://github.com/intel-lab-lkp/linux/commits/Jie-Gan/coresight-core-Refactoring-ctcu_get_active_port-and-make-it-generic/20251211-142430
base:   47b7b5e32bb7264b51b89186043e1ada4090b558
patch link:    https://lore.kernel.org/r/20251211-enable-byte-cntr-for-ctcu-v8-2-3e12ff313191%40oss.qualcomm.com
patch subject: [PATCH v8 2/8] coresight: core: add a new API to retrieve the helper device
config: arm64-randconfig-001-20251213 (https://download.01.org/0day-ci/archive/20251213/202512132024.rsZaNtbp-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 1335a05ab8bc8339ce24be3a9da89d8c3f4e0571)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251213/202512132024.rsZaNtbp-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512132024.rsZaNtbp-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> Warning: drivers/hwtracing/coresight/coresight-core.c:600 function parameter 'subtype' not described in 'coresight_get_helper'
>> Warning: drivers/hwtracing/coresight/coresight-core.c:600 function parameter 'subtype' not described in 'coresight_get_helper'

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

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