RE: [PATCH v13 7/8] coresight: tmc: integrate byte-cntr's sysfs_ops with tmc sysfs file_ops

Hi,

-----Original Message----- From: Jie Gan jie.gan@oss.qualcomm.com Sent: Monday, February 23, 2026 6:56 AM To: Suzuki Poulose Suzuki.Poulose@arm.com; Mike Leach Mike.Leach@arm.com; James Clark james.clark@linaro.org; Alexander Shishkin alexander.shishkin@linux.intel.com; Rob Herring robh@kernel.org; Krzysztof Kozlowski krzk+dt@kernel.org; Conor Dooley conor+dt@kernel.org; Tingwei Zhang tingwei.zhang@oss.qualcomm.com; Mao Jinlong jinlong.mao@oss.qualcomm.com; Bjorn Andersson andersson@kernel.org; Konrad Dybcio konradybcio@kernel.org Cc: coresight@lists.linaro.org; linux-arm-kernel@lists.infradead.org; linux- kernel@vger.kernel.org; linux-arm-msm@vger.kernel.org; devicetree@vger.kernel.org; Jie Gan jie.gan@oss.qualcomm.com Subject: [PATCH v13 7/8] coresight: tmc: integrate byte-cntr's sysfs_ops with tmc sysfs file_ops

Add code logic to invoke byte-cntr's tmc_sysfs_ops if the byte-cntr is enabled.

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

drivers/hwtracing/coresight/coresight-tmc-core.c | 53 +++++++++++++++++++++++- 1 file changed, 52 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index 32ca2ec994de..6486bdafdddc 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -31,6 +31,7 @@

#include "coresight-priv.h" #include "coresight-tmc.h" +#include "coresight-ctcu.h"

DEFINE_CORESIGHT_DEVLIST(etb_devs, "tmc_etb"); DEFINE_CORESIGHT_DEVLIST(etf_devs, "tmc_etf"); @@ -228,15 +229,47 @@ static int tmc_prepare_crashdata(struct tmc_drvdata *drvdata) return 0; }

+/* Return the byte-cntr's tmc_sysfs_ops if in using */ +static const struct tmc_sysfs_ops *tmc_get_byte_cntr_sysfs_ops(struct tmc_drvdata *drvdata) +{

• struct ctcu_byte_cntr *byte_cntr_data;
• struct ctcu_drvdata *ctcu_drvdata;
• struct coresight_device *ctcu;
• int port;
• ctcu = tmc_etr_get_ctcu_device(drvdata);
• if (!ctcu)

• return NULL;
  

• port = coresight_get_in_port(drvdata->csdev, ctcu);
• if (port < 0)

• return NULL;
  

• ctcu_drvdata = dev_get_drvdata(ctcu->dev.parent);
• byte_cntr_data = &ctcu_drvdata->byte_cntr_data[port];
• if (byte_cntr_data && byte_cntr_data->thresh_val)

• return ctcu_drvdata->byte_cntr_sysfs_ops;
  

• return NULL;

+}

Should be in a CTCU source file, not part of the common tmc code

static int tmc_read_prepare(struct tmc_drvdata *drvdata) {

• const struct tmc_sysfs_ops *byte_cntr_sysfs_ops; int ret = 0;

• byte_cntr_sysfs_ops = tmc_get_byte_cntr_sysfs_ops(drvdata);

• if (byte_cntr_sysfs_ops) {

• ret = byte_cntr_sysfs_ops->read_prepare(drvdata);
  

• goto out;
  

• }

• if (drvdata->sysfs_ops) ret = drvdata->sysfs_ops->read_prepare(drvdata); else ret = -EINVAL;

I understand ctcu usage is per session & per device, but at the start of the session would it not be better to have a function in the ctcu code that takes the drvdata->sysfs_ops and substitutes the callback directly, restoring it at the end.

+out: if (!ret) dev_dbg(&drvdata->csdev->dev, "TMC read start\n");

@@ -245,13 +278,21 @@ static int tmc_read_prepare(struct tmc_drvdata *drvdata)

static int tmc_read_unprepare(struct tmc_drvdata *drvdata) {

• const struct tmc_sysfs_ops *byte_cntr_sysfs_ops; int ret = 0;

• byte_cntr_sysfs_ops = tmc_get_byte_cntr_sysfs_ops(drvdata);

• if (byte_cntr_sysfs_ops) {

• ret = byte_cntr_sysfs_ops->read_unprepare(drvdata);
  

• goto out;
  

• }

• if (drvdata->sysfs_ops) ret = drvdata->sysfs_ops->read_unprepare(drvdata); else ret = -EINVAL;

Again override / restore over the session.

Regards

Mike

+out: if (!ret) dev_dbg(&drvdata->csdev->dev, "TMC read end\n");

@@ -277,6 +318,12 @@ static int tmc_open(struct inode *inode, struct file *file) static ssize_t tmc_get_sysfs_trace(struct tmc_drvdata *drvdata, loff_t pos, size_t len, char **bufpp) {

• const struct tmc_sysfs_ops *byte_cntr_sysfs_ops;
• byte_cntr_sysfs_ops = tmc_get_byte_cntr_sysfs_ops(drvdata);
• if (byte_cntr_sysfs_ops)

• return byte_cntr_sysfs_ops->get_trace_data(drvdata, pos,
  

len, bufpp);

• return drvdata->sysfs_ops->get_trace_data(drvdata, pos, len, bufpp);

}

@@ -297,7 +344,11 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len, return -EFAULT; }

• *ppos += actual;

• if (drvdata->reading_node)

• drvdata->reading_node->pos += actual;
  

• else

• *ppos += actual;
  

• dev_dbg(&drvdata->csdev->dev, "%zu bytes copied\n", actual);

  return actual;

-- 2.34.1