On 13/03/2026 09:02, 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 | 108 +++++++++++++++++++++++ drivers/hwtracing/coresight/coresight-tmc.h | 17 ++++ 3 files changed, 126 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..fdf23e1c932f 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1918,6 +1918,114 @@ 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 unused buffers from @drvdata->etr_buf_list and free them.
• */

+void tmc_clean_etr_buf_list(struct tmc_drvdata *drvdata) +{

• struct etr_buf_node *nd, *next;
• unsigned long flags;
• lockdep_assert_held(&drvdata->spinlock);
• list_for_each_entry_safe(nd, next, &drvdata->etr_buf_list, link) {

• if (nd->sysfs_buf == drvdata->sysfs_buf) {
  

• 	if (coresight_get_mode(drvdata->csdev) != CS_MODE_DISABLED) {
  

• 		/*
  

• 		 * Dont free the sysfs_buf, just remove it from list.
  

• 		 * drvdata->sysfs_buf will hold the buffer and free it later.
  

• 		 */
  

• 		nd->sysfs_buf = NULL;
  

• 		list_del(&nd->link);
  

• 		kfree(nd);
  

• 		continue;
  

• 	}
  

• }
  

• /* Free allocated buffers which are not utilized by ETR */
  

• raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
  

This is dangerous ! Restoring the irqflags to an uninitialised value from a different function thant where it was locked. Please clean this up

Suzuki

• tmc_etr_free_sysfs_buf(nd->sysfs_buf);
  

• raw_spin_lock_irqsave(&drvdata->spinlock, flags);
  

• drvdata->sysfs_buf = NULL;
  

• nd->sysfs_buf = NULL;
  

• list_del(&nd->link);
  

• 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;
• unsigned long flags;
• int i = 0, ret = 0;
• lockdep_assert_held(&drvdata->spinlock);
• /* 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) {

• raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
  

• /* 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);
  

• raw_spin_lock_irqsave(&drvdata->spinlock, flags);
  

• new_node->sysfs_buf = drvdata->sysfs_buf;
  

• new_node->is_free = false;
  

• list_add(&new_node->link, &drvdata->etr_buf_list);
  

• i++;
  

• }
• raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
• 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->link, &drvdata->etr_buf_list);
  

• i++;
  

• }
• /* Clean the list if there is an error */
• if (ret)

• tmc_clean_etr_buf_list(drvdata);
  

• raw_spin_lock_irqsave(&drvdata->spinlock, flags);
• 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..81237944b986 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.
• • @link: list_head of the node.
• */

+struct etr_buf_node {

• struct etr_buf *sysfs_buf;
• bool is_free;
• loff_t pos;
• struct list_head link;

+};

• /**
  • 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