Hi

On Fri, 25 Jul 2025 at 11:08, Jie Gan jie.gan@oss.qualcomm.com wrote:

Add a list to store allocated etr_buf.

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.

Signed-off-by: Jie Gan jie.gan@oss.qualcomm.com

.../hwtracing/coresight/coresight-tmc-core.c | 1 + drivers/hwtracing/coresight/coresight-tmc.h | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index be964656be93..4d249af93097 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -830,6 +830,7 @@ static int __tmc_probe(struct device *dev, struct resource *res) idr_init(&drvdata->idr); mutex_init(&drvdata->idr_mutex); dev_list = &etr_devs;

•           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.h b/drivers/hwtracing/coresight/coresight-tmc.h index 6541a27a018e..52ee5f8efe8c 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -208,6 +208,21 @@ struct tmc_resrv_buf { s64 len; };

+/**

• • @sysfs_buf: Allocated sysfs_buf.
• • @is_free: Indicates whether the buffer is free to choose.
• • @reading: Indicates whether the buffer is reading.
• • @pos: Position of the buffer.
• • @node: Node in etr_buf_list.
• */

+struct etr_buf_node {

•   struct etr_buf          *sysfs_buf;
  

•   bool                    is_free;
  

•   bool                    reading;
  

•   loff_t                  pos;
  

•   struct list_head        node;
  

+};

/**

• struct tmc_drvdata - specifics associated to an TMC component
• @pclk: APB clock if present, otherwise NULL

@@ -242,6 +257,8 @@ 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.
• • @reading_node: Available buffer for byte-cntr reading.
  */

struct tmc_drvdata { struct clk *pclk; @@ -271,6 +288,8 @@ 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_node     *reading_node;
  

Potential simplification:- do you need both reading_node here and reading in the etr_buf_node? reading_node handles the logic for which buffer is being read, while is_free handles the empty/full logic - reading seems unneeded?

};

struct etr_buf_operations {

2.34.1

regards

Mike