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