The coresight_disable_source_sysfs function should verify the
mode of the coresight device before disabling the source.
However, the mode for the TPDM device is always set to
CS_MODE_DISABLED, resulting in the check consistently failing.
As a result, TPDM cannot be properly disabled.

To fix the issue:
Configure CS_MODE_SYSFS/CS_MODE_PERF during the enablement of TPDM.
Configure CS_MODE_DISABLED during the disablement of TPDM.

Fixes: 1f5149c7751c("coresight: Move all sysfs code to sysfs file")
Signed-off-by: Jie Gan <quic_jiegan@quicinc.com>
---
 drivers/hwtracing/coresight/coresight-tpdm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
index a9708ab0d488..90a5105f6199 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.c
+++ b/drivers/hwtracing/coresight/coresight-tpdm.c
@@ -449,6 +449,11 @@ static int tpdm_enable(struct coresight_device *csdev, struct perf_event *event,
 		return -EBUSY;
 	}
 
+	if (!coresight_take_mode(csdev, mode)) {
+		spin_unlock(&drvdata->spinlock);
+		return -EBUSY;
+	}
+
 	__tpdm_enable(drvdata);
 	drvdata->enable = true;
 	spin_unlock(&drvdata->spinlock);
@@ -506,6 +511,7 @@ static void tpdm_disable(struct coresight_device *csdev,
 	}
 
 	__tpdm_disable(drvdata);
+	coresight_set_mode(csdev, CS_MODE_DISABLED);
 	drvdata->enable = false;
 	spin_unlock(&drvdata->spinlock);
 
-- 
2.34.1

On 25/06/2024 03:12, Jie Gan wrote:
> The coresight_disable_source_sysfs function should verify the
> mode of the coresight device before disabling the source.
> However, the mode for the TPDM device is always set to
> CS_MODE_DISABLED, resulting in the check consistently failing.
> As a result, TPDM cannot be properly disabled.
> 
> To fix the issue:
> Configure CS_MODE_SYSFS/CS_MODE_PERF during the enablement of TPDM.
> Configure CS_MODE_DISABLED during the disablement of TPDM.
> 
> Fixes: 1f5149c7751c("coresight: Move all sysfs code to sysfs file")

That looks like the wrong commit. This was a problem since the original
TPDM driver. I would say :

Fixes: b3c71626a933 ("Coresight: Add coresight TPDM source driver")

> Signed-off-by: Jie Gan <quic_jiegan@quicinc.com>

Otherwise, the patch looks good to me.

Please could you also fixup "dummy" source driver in a separate patch.

Suzuki

On Tue, Jun 25, 2024 at 01:24:11PM +0100, Suzuki K Poulose wrote:
> On 25/06/2024 03:12, Jie Gan wrote:
> > The coresight_disable_source_sysfs function should verify the
> > mode of the coresight device before disabling the source.
> > However, the mode for the TPDM device is always set to
> > CS_MODE_DISABLED, resulting in the check consistently failing.
> > As a result, TPDM cannot be properly disabled.
> > 
> > To fix the issue:
> > Configure CS_MODE_SYSFS/CS_MODE_PERF during the enablement of TPDM.
> > Configure CS_MODE_DISABLED during the disablement of TPDM.
> > 
> > Fixes: 1f5149c7751c("coresight: Move all sysfs code to sysfs file")
> 
> That looks like the wrong commit. This was a problem since the original
> TPDM driver. I would say :
> 
> Fixes: b3c71626a933 ("Coresight: Add coresight TPDM source driver")
I will correct the Fixes tag and re-send the patch.

> 
> > Signed-off-by: Jie Gan <quic_jiegan@quicinc.com>
> 
> Otherwise, the patch looks good to me.
> 
> Please could you also fixup "dummy" source driver in a separate patch.
Sure.

> 
> Suzuki
> 

Thanks,
Jie