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.
Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 30 ++++++++++++++++++++
drivers/hwtracing/coresight/coresight-priv.h | 2 ++
2 files changed, 32 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 5297a5ff7921..76e10c36a8a1 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -580,6 +580,36 @@ 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,
+ int type)
+{
+ int i;
+ struct coresight_device *helper;
+
+ 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 == type)
+ return helper;
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(coresight_get_helper);
+
/**
* coresight_get_port_helper: get the in-port number of the helper device
* that is connected to the csdev.
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index 07a5f03de81d..5b912eb60401 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -158,6 +158,8 @@ void coresight_path_assign_trace_id(struct coresight_path *path,
enum cs_mode mode);
int coresight_get_port_helper(struct coresight_device *csdev,
struct coresight_device *helper);
+struct coresight_device *coresight_get_helper(struct coresight_device *csdev,
+ int type);
#if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM3X)
int etm_readl_cp14(u32 off, unsigned int *val);
--
2.34.1Hi,
On Mon, 14 Jul 2025 at 07:31, Jie Gan <jie.gan@oss.qualcomm.com> 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.
>
> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
> ---
> drivers/hwtracing/coresight/coresight-core.c | 30 ++++++++++++++++++++
> drivers/hwtracing/coresight/coresight-priv.h | 2 ++
> 2 files changed, 32 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index 5297a5ff7921..76e10c36a8a1 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -580,6 +580,36 @@ 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,
> + int type)
> +{
> + int i;
> + struct coresight_device *helper;
> +
> + for (i = 0; i < csdev->pdata->nr_outconns; ++i) {
> + helper = csdev->pdata->out_conns[i]->dest_dev;
> + if (!helper || !coresight_is_helper(helper))
> + continue;
> +
Manipulating the connections list almost certainly requires some
locking. See other functions in this file
Mike
> + if (helper->subtype.helper_subtype == type)
> + return helper;
> + }
> +
> + return NULL;
> +}
> +EXPORT_SYMBOL_GPL(coresight_get_helper);
> +
> /**
> * coresight_get_port_helper: get the in-port number of the helper device
> * that is connected to the csdev.
> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> index 07a5f03de81d..5b912eb60401 100644
> --- a/drivers/hwtracing/coresight/coresight-priv.h
> +++ b/drivers/hwtracing/coresight/coresight-priv.h
> @@ -158,6 +158,8 @@ void coresight_path_assign_trace_id(struct coresight_path *path,
> enum cs_mode mode);
> int coresight_get_port_helper(struct coresight_device *csdev,
> struct coresight_device *helper);
> +struct coresight_device *coresight_get_helper(struct coresight_device *csdev,
> + int type);
>
> #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM3X)
> int etm_readl_cp14(u32 off, unsigned int *val);
> --
> 2.34.1
>
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
On 7/18/2025 4:37 PM, Mike Leach wrote:
> Hi,
>
> On Mon, 14 Jul 2025 at 07:31, Jie Gan <jie.gan@oss.qualcomm.com> 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.
>>
>> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
>> ---
>> drivers/hwtracing/coresight/coresight-core.c | 30 ++++++++++++++++++++
>> drivers/hwtracing/coresight/coresight-priv.h | 2 ++
>> 2 files changed, 32 insertions(+)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
>> index 5297a5ff7921..76e10c36a8a1 100644
>> --- a/drivers/hwtracing/coresight/coresight-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>> @@ -580,6 +580,36 @@ 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,
>> + int type)
>> +{
>> + int i;
>> + struct coresight_device *helper;
>> +
>> + for (i = 0; i < csdev->pdata->nr_outconns; ++i) {
>> + helper = csdev->pdata->out_conns[i]->dest_dev;
>> + if (!helper || !coresight_is_helper(helper))
>> + continue;
>> +
>
> Manipulating the connections list almost certainly requires some
> locking. See other functions in this file
>
Thanks for pointing out. I will fix it in next version.
Thanks,
Jie
> Mike
>
>
>> + if (helper->subtype.helper_subtype == type)
>> + return helper;
>> + }
>> +
>> + return NULL;
>> +}
>> +EXPORT_SYMBOL_GPL(coresight_get_helper);
>> +
>> /**
>> * coresight_get_port_helper: get the in-port number of the helper device
>> * that is connected to the csdev.
>> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
>> index 07a5f03de81d..5b912eb60401 100644
>> --- a/drivers/hwtracing/coresight/coresight-priv.h
>> +++ b/drivers/hwtracing/coresight/coresight-priv.h
>> @@ -158,6 +158,8 @@ void coresight_path_assign_trace_id(struct coresight_path *path,
>> enum cs_mode mode);
>> int coresight_get_port_helper(struct coresight_device *csdev,
>> struct coresight_device *helper);
>> +struct coresight_device *coresight_get_helper(struct coresight_device *csdev,
>> + int type);
>>
>> #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM3X)
>> int etm_readl_cp14(u32 off, unsigned int *val);
>> --
>> 2.34.1
>>
>
>
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