[PATCH v2] coresight: tpda: fix the logic to setup the element size

[PATCH v2] coresight: tpda: fix the logic to setup the element size

[Jie Gan]

Some TPDM devices support both CMB and DSB datasets, requiring
the system to enable the port with both corresponding element sizes.

Currently, the logic treats tpdm_read_element_size as successful if
the CMB element size is retrieved correctly, regardless of whether
the DSB element size is obtained. This behavior causes issues
when parsing data from TPDM devices that depend on both element sizes.

To address this, the function should explicitly fail if the DSB
element size cannot be read correctly.

Fixes: e6d7f5252f73 ("coresight-tpda: Add support to configure CMB element")
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
---
Changes in V2:
1. rebased the patch.
2. Add James's reviewed-by tag.
Link to V1 - https://lore.kernel.org/all/20250806080931.14322-1-jie.gan@oss.qualcomm.com/
---
 drivers/hwtracing/coresight/coresight-tpda.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
index 0633f04beb24..333b3cb23685 100644
--- a/drivers/hwtracing/coresight/coresight-tpda.c
+++ b/drivers/hwtracing/coresight/coresight-tpda.c
@@ -71,6 +71,8 @@ static int tpdm_read_element_size(struct tpda_drvdata *drvdata,
 	if (tpdm_data->dsb) {
 		rc = fwnode_property_read_u32(dev_fwnode(csdev->dev.parent),
 				"qcom,dsb-element-bits", &drvdata->dsb_esize);
+		if (rc)
+			goto out;
 	}
 
 	if (tpdm_data->cmb) {
@@ -78,6 +80,7 @@ static int tpdm_read_element_size(struct tpda_drvdata *drvdata,
 				"qcom,cmb-element-bits", &drvdata->cmb_esize);
 	}
 
+out:
 	if (rc)
 		dev_warn_once(&csdev->dev,
 			"Failed to read TPDM Element size: %d\n", rc);

---
base-commit: 5d50cf9f7cf20a17ac469c20a2e07c29c1f6aab7
change-id: 20250906-fix_element_size_issue-e740086291fa

Best regards,
-- 
Jie Gan <jie.gan@oss.qualcomm.com>

Re: [PATCH v2] coresight: tpda: fix the logic to setup the element size

[Suzuki K Poulose]

On Sat, 06 Sep 2025 07:53:04 +0800, Jie Gan wrote:
> Some TPDM devices support both CMB and DSB datasets, requiring
> the system to enable the port with both corresponding element sizes.
> 
> Currently, the logic treats tpdm_read_element_size as successful if
> the CMB element size is retrieved correctly, regardless of whether
> the DSB element size is obtained. This behavior causes issues
> when parsing data from TPDM devices that depend on both element sizes.
> 
> [...]

Applied, thanks!

[1/1] coresight: tpda: fix the logic to setup the element size
      https://git.kernel.org/coresight/c/fd6974c19eb3

Best regards,
-- 
Suzuki K Poulose <suzuki.poulose@arm.com>