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  3. [PATCH v14 0/7] coresight: ctcu: Enable byte-cntr function for TMC ETR
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[PATCH v14 2/7] coresight: tmc: add create/clean functions for etr_buf_list

Jie Gan posted 7 patches 1 month ago
There is a newer version of this series
[PATCH v14 2/7] coresight: tmc: add create/clean functions for etr_buf_list
Posted by Jie Gan 1 month ago 
Introduce functions for creating and inserting or removing the
etr_buf_node to/from the etr_buf_list.

The byte-cntr functionality requires two etr_buf to receive trace data.
The active etr_buf collects the trace data from source device, while the
byte-cntr reading function accesses the deactivated etr_buf after is
has been filled and synced, transferring data to the userspace.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-core.c |  1 +
 drivers/hwtracing/coresight/coresight-tmc-etr.c  | 94 ++++++++++++++++++++++++
 drivers/hwtracing/coresight/coresight-tmc.h      | 17 +++++
 3 files changed, 112 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index c89fe996af23..bac3278ef4dd 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -835,6 +835,7 @@ static int __tmc_probe(struct device *dev, struct resource *res)
 		idr_init(&drvdata->idr);
 		mutex_init(&drvdata->idr_mutex);
 		dev_list = "tmc_etr";
+		INIT_LIST_HEAD(&drvdata->etr_buf_list);
 		break;
 	case TMC_CONFIG_TYPE_ETF:
 		desc.groups = coresight_etf_groups;
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 4dc1defe27a5..15c0874ff641 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1918,6 +1918,100 @@ const struct coresight_ops tmc_etr_cs_ops = {
 	.panic_ops	= &tmc_etr_sync_ops,
 };
 
+/**
+ * tmc_clean_etr_buf_list - clean the etr_buf_list.
+ * @drvdata:	driver data of the TMC device.
+ *
+ * Remove the allocated node from the list and free the extra buffer.
+ */
+void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata)
+{
+	struct etr_buf_node *nd, *next;
+
+	list_for_each_entry_safe(nd, next, &drvdata->etr_buf_list, node) {
+		if (nd->sysfs_buf == drvdata->sysfs_buf) {
+			if (coresight_get_mode(drvdata->csdev) == CS_MODE_DISABLED) {
+				drvdata->sysfs_buf = NULL;
+				tmc_free_etr_buf(nd->sysfs_buf);
+				nd->sysfs_buf = NULL;
+			}
+			list_del(&nd->node);
+			kfree(nd);
+		} else {
+			/* Free allocated buffers which are not utilized by ETR */
+			list_del(&nd->node);
+			tmc_free_etr_buf(nd->sysfs_buf);
+			nd->sysfs_buf = NULL;
+			kfree(nd);
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(tmc_clean_etr_buf_list);
+
+/**
+ * tmc_create_etr_buf_list - create a list to manage the etr_buf_node.
+ * @drvdata:	driver data of the TMC device.
+ * @num_nodes:	number of nodes want to create with the list.
+ *
+ * Return 0 upon success and return the error number if fail.
+ */
+int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes)
+{
+	struct etr_buf_node *new_node;
+	struct etr_buf *sysfs_buf;
+	int i = 0, ret = 0;
+
+	/* We dont need a list if there is only one node */
+	if (num_nodes < 2)
+		return -EINVAL;
+
+	/* We expect that sysfs_buf in drvdata has already been allocated. */
+	if (drvdata->sysfs_buf) {
+		/* Directly insert the allocated sysfs_buf into the list first */
+		new_node = kzalloc_obj(*new_node, GFP_KERNEL);
+		if (IS_ERR(new_node))
+			return PTR_ERR(new_node);
+
+		new_node->sysfs_buf = drvdata->sysfs_buf;
+		new_node->is_free = false;
+		list_add(&new_node->node, &drvdata->etr_buf_list);
+		i++;
+	}
+
+	while (i < num_nodes) {
+		new_node = kzalloc_obj(*new_node, GFP_KERNEL);
+		if (IS_ERR(new_node)) {
+			ret = PTR_ERR(new_node);
+			break;
+		}
+
+		sysfs_buf = tmc_alloc_etr_buf(drvdata, drvdata->size, 0, cpu_to_node(0), NULL);
+		if (IS_ERR(sysfs_buf)) {
+			kfree(new_node);
+			ret = PTR_ERR(sysfs_buf);
+			break;
+		}
+
+		/* We dont have a available sysfs_buf in drvdata, setup one */
+		if (!drvdata->sysfs_buf) {
+			drvdata->sysfs_buf = sysfs_buf;
+			new_node->is_free = false;
+		} else
+			new_node->is_free = true;
+
+		new_node->sysfs_buf = sysfs_buf;
+		list_add(&new_node->node, &drvdata->etr_buf_list);
+		i++;
+	}
+
+	/* Clean the list if there is an error */
+	if (ret)
+		tmc_clean_etr_buf_list(drvdata);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tmc_create_etr_buf_list);
+
 int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
 {
 	int ret = 0;
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 319a354ede9f..5ac07e8dd5ff 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -208,6 +208,19 @@ struct tmc_resrv_buf {
 	s64		len;
 };
 
+/**
+ * @sysfs_buf:	Allocated sysfs_buf.
+ * @is_free:	Indicates whether the buffer is free to choose.
+ * @pos:	Position of the buffer.
+ * @node:	Node in etr_buf_list.
+ */
+struct etr_buf_node {
+	struct etr_buf		*sysfs_buf;
+	bool			is_free;
+	loff_t			pos;
+	struct list_head	node;
+};
+
 /**
  * struct tmc_drvdata - specifics associated to an TMC component
  * @atclk:	optional clock for the core parts of the TMC.
@@ -245,6 +258,7 @@ struct tmc_resrv_buf {
  *		(after crash) by default.
  * @crash_mdata: Reserved memory for storing tmc crash metadata.
  *		 Used by ETR/ETF.
+ * @etr_buf_list: List that is used to manage allocated etr_buf.
  */
 struct tmc_drvdata {
 	struct clk		*atclk;
@@ -275,6 +289,7 @@ struct tmc_drvdata {
 	struct etr_buf		*perf_buf;
 	struct tmc_resrv_buf	resrv_buf;
 	struct tmc_resrv_buf	crash_mdata;
+	struct list_head        etr_buf_list;
 };
 
 struct etr_buf_operations {
@@ -447,5 +462,7 @@ struct etr_buf *tmc_etr_get_buffer(struct coresight_device *csdev,
 				   enum cs_mode mode,
 				   struct coresight_path *path);
 extern const struct attribute_group coresight_etr_group;
+void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata);
+int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes);
 
 #endif

-- 
2.34.1
Re: [PATCH v14 2/7] coresight: tmc: add create/clean functions for etr_buf_list
Posted by Suzuki K Poulose 1 month ago 
On 09/03/2026 09:47, Jie Gan wrote:
> Introduce functions for creating and inserting or removing the
> etr_buf_node to/from the etr_buf_list.
> 
> The byte-cntr functionality requires two etr_buf to receive trace data.
> The active etr_buf collects the trace data from source device, while the
> byte-cntr reading function accesses the deactivated etr_buf after is
> has been filled and synced, transferring data to the userspace.
> 
> Reviewed-by: Mike Leach <mike.leach@linaro.org>
> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
> ---
>   drivers/hwtracing/coresight/coresight-tmc-core.c |  1 +
>   drivers/hwtracing/coresight/coresight-tmc-etr.c  | 94 ++++++++++++++++++++++++
>   drivers/hwtracing/coresight/coresight-tmc.h      | 17 +++++
>   3 files changed, 112 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> index c89fe996af23..bac3278ef4dd 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
> @@ -835,6 +835,7 @@ static int __tmc_probe(struct device *dev, struct resource *res)
>   		idr_init(&drvdata->idr);
>   		mutex_init(&drvdata->idr_mutex);
>   		dev_list = "tmc_etr";
> +		INIT_LIST_HEAD(&drvdata->etr_buf_list);
>   		break;
>   	case TMC_CONFIG_TYPE_ETF:
>   		desc.groups = coresight_etf_groups;
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> index 4dc1defe27a5..15c0874ff641 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> @@ -1918,6 +1918,100 @@ const struct coresight_ops tmc_etr_cs_ops = {
>   	.panic_ops	= &tmc_etr_sync_ops,
>   };
>   
> +/**
> + * tmc_clean_etr_buf_list - clean the etr_buf_list.
> + * @drvdata:	driver data of the TMC device.
> + *
> + * Remove the allocated node from the list and free the extra buffer.
> + */
> +void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata)
> +{
...

> +}
> +EXPORT_SYMBOL_GPL(tmc_clean_etr_buf_list);
> +
> +/**
> + * tmc_create_etr_buf_list - create a list to manage the etr_buf_node.
> + * @drvdata:	driver data of the TMC device.
> + * @num_nodes:	number of nodes want to create with the list.
> + *
> + * Return 0 upon success and return the error number if fail.
> + */
> +int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes)
> +{

...


> +EXPORT_SYMBOL_GPL(tmc_create_etr_buf_list);

Given the above functions are "EXPORTED" please could you make sure that
the locking requirements are documented and asserted (lockdep_assert)
in the functions ?


Suzuki


> +
>   int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
>   {
>   	int ret = 0;
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
> index 319a354ede9f..5ac07e8dd5ff 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.h
> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
> @@ -208,6 +208,19 @@ struct tmc_resrv_buf {
>   	s64		len;
>   };
>   
> +/**
> + * @sysfs_buf:	Allocated sysfs_buf.
> + * @is_free:	Indicates whether the buffer is free to choose.
> + * @pos:	Position of the buffer.
> + * @node:	Node in etr_buf_list.
> + */
> +struct etr_buf_node {
> +	struct etr_buf		*sysfs_buf;
> +	bool			is_free;
> +	loff_t			pos;
> +	struct list_head	node;
> +};
> +
>   /**
>    * struct tmc_drvdata - specifics associated to an TMC component
>    * @atclk:	optional clock for the core parts of the TMC.
> @@ -245,6 +258,7 @@ struct tmc_resrv_buf {
>    *		(after crash) by default.
>    * @crash_mdata: Reserved memory for storing tmc crash metadata.
>    *		 Used by ETR/ETF.
> + * @etr_buf_list: List that is used to manage allocated etr_buf.
>    */
>   struct tmc_drvdata {
>   	struct clk		*atclk;
> @@ -275,6 +289,7 @@ struct tmc_drvdata {
>   	struct etr_buf		*perf_buf;
>   	struct tmc_resrv_buf	resrv_buf;
>   	struct tmc_resrv_buf	crash_mdata;
> +	struct list_head        etr_buf_list;
>   };
>   
>   struct etr_buf_operations {
> @@ -447,5 +462,7 @@ struct etr_buf *tmc_etr_get_buffer(struct coresight_device *csdev,
>   				   enum cs_mode mode,
>   				   struct coresight_path *path);
>   extern const struct attribute_group coresight_etr_group;
> +void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata);
> +int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes);
>   
>   #endif
>
Re: [PATCH v14 2/7] coresight: tmc: add create/clean functions for etr_buf_list
Posted by Jie Gan 1 month ago 

On 3/9/2026 6:02 PM, Suzuki K Poulose wrote:
> On 09/03/2026 09:47, Jie Gan wrote:
>> Introduce functions for creating and inserting or removing the
>> etr_buf_node to/from the etr_buf_list.
>>
>> The byte-cntr functionality requires two etr_buf to receive trace data.
>> The active etr_buf collects the trace data from source device, while the
>> byte-cntr reading function accesses the deactivated etr_buf after is
>> has been filled and synced, transferring data to the userspace.
>>
>> Reviewed-by: Mike Leach <mike.leach@linaro.org>
>> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-tmc-core.c |  1 +
>>   drivers/hwtracing/coresight/coresight-tmc-etr.c  | 94 ++++++++++++++ 
>> ++++++++++
>>   drivers/hwtracing/coresight/coresight-tmc.h      | 17 +++++
>>   3 files changed, 112 insertions(+)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/ 
>> drivers/hwtracing/coresight/coresight-tmc-core.c
>> index c89fe996af23..bac3278ef4dd 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
>> @@ -835,6 +835,7 @@ static int __tmc_probe(struct device *dev, struct 
>> resource *res)
>>           idr_init(&drvdata->idr);
>>           mutex_init(&drvdata->idr_mutex);
>>           dev_list = "tmc_etr";
>> +        INIT_LIST_HEAD(&drvdata->etr_buf_list);
>>           break;
>>       case TMC_CONFIG_TYPE_ETF:
>>           desc.groups = coresight_etf_groups;
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/ 
>> drivers/hwtracing/coresight/coresight-tmc-etr.c
>> index 4dc1defe27a5..15c0874ff641 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
>> @@ -1918,6 +1918,100 @@ const struct coresight_ops tmc_etr_cs_ops = {
>>       .panic_ops    = &tmc_etr_sync_ops,
>>   };
>> +/**
>> + * tmc_clean_etr_buf_list - clean the etr_buf_list.
>> + * @drvdata:    driver data of the TMC device.
>> + *
>> + * Remove the allocated node from the list and free the extra buffer.
>> + */
>> +void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata)
>> +{
> ...
> 
>> +}
>> +EXPORT_SYMBOL_GPL(tmc_clean_etr_buf_list);
>> +
>> +/**
>> + * tmc_create_etr_buf_list - create a list to manage the etr_buf_node.
>> + * @drvdata:    driver data of the TMC device.
>> + * @num_nodes:    number of nodes want to create with the list.
>> + *
>> + * Return 0 upon success and return the error number if fail.
>> + */
>> +int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes)
>> +{
> 
> ...
> 
> 
>> +EXPORT_SYMBOL_GPL(tmc_create_etr_buf_list);
> 
> Given the above functions are "EXPORTED" please could you make sure that
> the locking requirements are documented and asserted (lockdep_assert)
> in the functions ?
> 

Will checking the locking scenario here and asserted with 
lockdep_assert_held.

These two functions should be protected with tmc_drvdata->spinlock.

Thanks,
Jie

> 
> Suzuki
> 
> 
>> +
>>   int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
>>   {
>>       int ret = 0;
>> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/ 
>> hwtracing/coresight/coresight-tmc.h
>> index 319a354ede9f..5ac07e8dd5ff 100644
>> --- a/drivers/hwtracing/coresight/coresight-tmc.h
>> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
>> @@ -208,6 +208,19 @@ struct tmc_resrv_buf {
>>       s64        len;
>>   };
>> +/**
>> + * @sysfs_buf:    Allocated sysfs_buf.
>> + * @is_free:    Indicates whether the buffer is free to choose.
>> + * @pos:    Position of the buffer.
>> + * @node:    Node in etr_buf_list.
>> + */
>> +struct etr_buf_node {
>> +    struct etr_buf        *sysfs_buf;
>> +    bool            is_free;
>> +    loff_t            pos;
>> +    struct list_head    node;
>> +};
>> +
>>   /**
>>    * struct tmc_drvdata - specifics associated to an TMC component
>>    * @atclk:    optional clock for the core parts of the TMC.
>> @@ -245,6 +258,7 @@ struct tmc_resrv_buf {
>>    *        (after crash) by default.
>>    * @crash_mdata: Reserved memory for storing tmc crash metadata.
>>    *         Used by ETR/ETF.
>> + * @etr_buf_list: List that is used to manage allocated etr_buf.
>>    */
>>   struct tmc_drvdata {
>>       struct clk        *atclk;
>> @@ -275,6 +289,7 @@ struct tmc_drvdata {
>>       struct etr_buf        *perf_buf;
>>       struct tmc_resrv_buf    resrv_buf;
>>       struct tmc_resrv_buf    crash_mdata;
>> +    struct list_head        etr_buf_list;
>>   };
>>   struct etr_buf_operations {
>> @@ -447,5 +462,7 @@ struct etr_buf *tmc_etr_get_buffer(struct 
>> coresight_device *csdev,
>>                      enum cs_mode mode,
>>                      struct coresight_path *path);
>>   extern const struct attribute_group coresight_etr_group;
>> +void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata);
>> +int tmc_create_etr_buf_list(struct tmc_drvdata *drvdata, int num_nodes);
>>   #endif
>>
> 
>

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