[PATCH v2 0/4] coresight: Fix miscellaneous problems with CLAIM tags

[PATCH v2 0/4] coresight: Fix miscellaneous problems with CLAIM tags

[Mathieu Poirier]

This set addresses problems observed with the CLAIM tag feature.  The first
patch adds support for CLAIM tags to the ETB10 drivers.  The remaining 3 
patches deal with properly handling the tags on ETF and ETM3x devices.

Regards,
Mathieu

Changes since V1:
* Added Suzuki's review tags to patch 1 and 2.
* Addressed ordering issued in ETM3x enable/disable functions (Leo Yan)
 

Mathieu Poirier (4):
  coresight: etb10: Add support for CLAIM tag
  coresight: etf: Release CLAIM tag after disabling the HW
  coresight: etm3x: Deal with CLAIM tag before and after accessing HW
  coresight: etm3x: Release CLAIM tag when operated from perf

 drivers/hwtracing/coresight/coresight-etb10.c   | 23 +++++++++++++++++------
 drivers/hwtracing/coresight/coresight-etm3x.c   | 17 +++++++++--------
 drivers/hwtracing/coresight/coresight-tmc-etf.c |  2 +-
 3 files changed, 27 insertions(+), 15 deletions(-)

-- 
2.7.4

[PATCH v2 1/4] coresight: etb10: Add support for CLAIM tag

[Mathieu Poirier]

Following in the footstep of what was done for other CoreSight devices,
add CLAIM tag support to ETB10 in order to synchronise access to the
HW between the kernel and an external agent.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-etb10.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 824be0c5f592..105782ea64c7 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -136,6 +136,11 @@ static void __etb_enable_hw(struct etb_drvdata *drvdata)
 
 static int etb_enable_hw(struct etb_drvdata *drvdata)
 {
+	int rc = coresight_claim_device(drvdata->base);
+
+	if (rc)
+		return rc;
+
 	__etb_enable_hw(drvdata);
 	return 0;
 }
@@ -223,7 +228,7 @@ static int etb_enable(struct coresight_device *csdev, u32 mode, void *data)
 	return 0;
 }
 
-static void etb_disable_hw(struct etb_drvdata *drvdata)
+static void __etb_disable_hw(struct etb_drvdata *drvdata)
 {
 	u32 ffcr;
 
@@ -313,6 +318,13 @@ static void etb_dump_hw(struct etb_drvdata *drvdata)
 	CS_LOCK(drvdata->base);
 }
 
+static void etb_disable_hw(struct etb_drvdata *drvdata)
+{
+	__etb_disable_hw(drvdata);
+	etb_dump_hw(drvdata);
+	coresight_disclaim_device(drvdata->base);
+}
+
 static void etb_disable(struct coresight_device *csdev)
 {
 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -323,7 +335,6 @@ static void etb_disable(struct coresight_device *csdev)
 	/* Disable the ETB only if it needs to */
 	if (drvdata->mode != CS_MODE_DISABLED) {
 		etb_disable_hw(drvdata);
-		etb_dump_hw(drvdata);
 		drvdata->mode = CS_MODE_DISABLED;
 	}
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -402,7 +413,7 @@ static unsigned long etb_update_buffer(struct coresight_device *csdev,
 
 	capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS;
 
-	etb_disable_hw(drvdata);
+	__etb_disable_hw(drvdata);
 	CS_UNLOCK(drvdata->base);
 
 	/* unit is in words, not bytes */
@@ -510,7 +521,7 @@ static unsigned long etb_update_buffer(struct coresight_device *csdev,
 		handle->head = (cur * PAGE_SIZE) + offset;
 		to_read = buf->nr_pages << PAGE_SHIFT;
 	}
-	etb_enable_hw(drvdata);
+	__etb_enable_hw(drvdata);
 	CS_LOCK(drvdata->base);
 
 	return to_read;
@@ -534,9 +545,9 @@ static void etb_dump(struct etb_drvdata *drvdata)
 
 	spin_lock_irqsave(&drvdata->spinlock, flags);
 	if (drvdata->mode == CS_MODE_SYSFS) {
-		etb_disable_hw(drvdata);
+		__etb_disable_hw(drvdata);
 		etb_dump_hw(drvdata);
-		etb_enable_hw(drvdata);
+		__etb_enable_hw(drvdata);
 	}
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
-- 
2.7.4

[PATCH v2 2/4] coresight: etf: Release CLAIM tag after disabling the HW

[Mathieu Poirier]

This patch rectifies the sequence of events in function
tmc_etb_disable_hw() by disabling the HW first and then releasing the
CLAIM tag.  Otherwise we could be corrupting the configuration done by an
external agent that would have claimed the device after we have released
it.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 5864ac55e275..a5f053f2db2c 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -86,8 +86,8 @@ static void __tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
 
 static void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
 {
-	coresight_disclaim_device(drvdata->base);
 	__tmc_etb_disable_hw(drvdata);
+	coresight_disclaim_device(drvdata->base);
 }
 
 static void __tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
-- 
2.7.4

[PATCH v2 3/4] coresight: etm3x: Deal with CLAIM tag before and after accessing HW

[Mathieu Poirier]

This patch moves access to the CLAIM tag so that no modification to the HW
happens before and after the CLAIM operation has been carried.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/hwtracing/coresight/coresight-etm3x.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index fd5c4cca7db5..4f638d81a66a 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -363,15 +363,16 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
 
 	CS_UNLOCK(drvdata->base);
 
+	rc = coresight_claim_device_unlocked(drvdata->base);
+	if (rc)
+		goto done;
+
 	/* Turn engine on */
 	etm_clr_pwrdwn(drvdata);
 	/* Apply power to trace registers */
 	etm_set_pwrup(drvdata);
 	/* Make sure all registers are accessible */
 	etm_os_unlock(drvdata);
-	rc = coresight_claim_device_unlocked(drvdata->base);
-	if (rc)
-		goto done;
 
 	etm_set_prog(drvdata);
 
@@ -422,12 +423,11 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
 	etm_clr_prog(drvdata);
 
 done:
-	if (rc)
-		etm_set_pwrdwn(drvdata);
 	CS_LOCK(drvdata->base);
 
-	dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
-		drvdata->cpu, rc);
+	if (!rc)
+		dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
+			drvdata->cpu, rc);
 	return rc;
 }
 
@@ -577,9 +577,9 @@ static void etm_disable_hw(void *info)
 	for (i = 0; i < drvdata->nr_cntr; i++)
 		config->cntr_val[i] = etm_readl(drvdata, ETMCNTVRn(i));
 
+	etm_set_pwrdwn(drvdata);
 	coresight_disclaim_device_unlocked(drvdata->base);
 
-	etm_set_pwrdwn(drvdata);
 	CS_LOCK(drvdata->base);
 
 	dev_dbg(drvdata->dev, "cpu: %d disable smp call done\n", drvdata->cpu);
-- 
2.7.4

[PATCH v2 4/4] coresight: etm3x: Release CLAIM tag when operated from perf

[Mathieu Poirier]

This patch deals with the release of the CLAIM tag when the ETM is
operated from perf.  Otherwise the tag is left asserted and subsequent
requests to use the device fail.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/hwtracing/coresight/coresight-etm3x.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index 4f638d81a66a..d7f452e62193 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -602,6 +602,7 @@ static void etm_disable_perf(struct coresight_device *csdev)
 	 * power down the tracer.
 	 */
 	etm_set_pwrdwn(drvdata);
+	coresight_disclaim_device_unlocked(drvdata->base);
 
 	CS_LOCK(drvdata->base);
 }
-- 
2.7.4

Re: [PATCH v2 3/4] coresight: etm3x: Deal with CLAIM tag before and after accessing HW

[Suzuki K Poulose]

Hi,

On 07/11/2018 23:08, Mathieu Poirier wrote:
> This patch moves access to the CLAIM tag so that no modification to the HW
> happens before and after the CLAIM operation has been carried.
> 
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> ---
>   drivers/hwtracing/coresight/coresight-etm3x.c | 16 ++++++++--------
>   1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
> index fd5c4cca7db5..4f638d81a66a 100644
> --- a/drivers/hwtracing/coresight/coresight-etm3x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x.c
> @@ -363,15 +363,16 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
>   
>   	CS_UNLOCK(drvdata->base);
>   
> +	rc = coresight_claim_device_unlocked(drvdata->base);
> +	if (rc)
> +		goto done;
> +
>   	/* Turn engine on */
>   	etm_clr_pwrdwn(drvdata);
>   	/* Apply power to trace registers */
>   	etm_set_pwrup(drvdata);
>   	/* Make sure all registers are accessible */
>   	etm_os_unlock(drvdata);
> -	rc = coresight_claim_device_unlocked(drvdata->base);
> -	if (rc)
> -		goto done;
>   
>   	etm_set_prog(drvdata);
>   
> @@ -422,12 +423,11 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
>   	etm_clr_prog(drvdata);
>   
>   done:
> -	if (rc)
> -		etm_set_pwrdwn(drvdata);
>   	CS_LOCK(drvdata->base);
>   
> -	dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
> -		drvdata->cpu, rc);
> +	if (!rc)
> +		dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
> +			drvdata->cpu, rc);

Isn't it good to report the failure case too ? Anyway it is dev_dbg and
will be a useful info when we debug issues. Otherwise,

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>

>   	return rc;
>   }
>   
> @@ -577,9 +577,9 @@ static void etm_disable_hw(void *info)
>   	for (i = 0; i < drvdata->nr_cntr; i++)
>   		config->cntr_val[i] = etm_readl(drvdata, ETMCNTVRn(i));
>   
> +	etm_set_pwrdwn(drvdata);
>   	coresight_disclaim_device_unlocked(drvdata->base);
>   
> -	etm_set_pwrdwn(drvdata);
>   	CS_LOCK(drvdata->base);
>   
>   	dev_dbg(drvdata->dev, "cpu: %d disable smp call done\n", drvdata->cpu);
> 

Re: [PATCH v2 4/4] coresight: etm3x: Release CLAIM tag when operated from perf

[Suzuki K Poulose]

On 07/11/2018 23:08, Mathieu Poirier wrote:
> This patch deals with the release of the CLAIM tag when the ETM is
> operated from perf.  Otherwise the tag is left asserted and subsequent
> requests to use the device fail.
> 
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> ---
>   drivers/hwtracing/coresight/coresight-etm3x.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
> index 4f638d81a66a..d7f452e62193 100644
> --- a/drivers/hwtracing/coresight/coresight-etm3x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x.c
> @@ -602,6 +602,7 @@ static void etm_disable_perf(struct coresight_device *csdev)
>   	 * power down the tracer.
>   	 */
>   	etm_set_pwrdwn(drvdata);
> +	coresight_disclaim_device_unlocked(drvdata->base);

Thanks for fixing this. IIUC, I think we have a problem in general with
mixing perf vs sysfs. Once a perf session uses the etm3x, we overwrite
the drvdata->config with the perf event specific controls and the sysfs
user may not be aware of that. We may have to do something similar we do
for ETR buf for sysfs/perf sessions. And then we may be able to merge
the enable/disable routines.

For this patch:

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Re: [PATCH v2 3/4] coresight: etm3x: Deal with CLAIM tag before and after accessing HW

[Mathieu Poirier]

On Thu, 8 Nov 2018 at 10:13, Suzuki K Poulose <suzuki.poulose@arm.com> wrote:
>
> Hi,
>
> On 07/11/2018 23:08, Mathieu Poirier wrote:
> > This patch moves access to the CLAIM tag so that no modification to the HW
> > happens before and after the CLAIM operation has been carried.
> >
> > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> > ---
> >   drivers/hwtracing/coresight/coresight-etm3x.c | 16 ++++++++--------
> >   1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
> > index fd5c4cca7db5..4f638d81a66a 100644
> > --- a/drivers/hwtracing/coresight/coresight-etm3x.c
> > +++ b/drivers/hwtracing/coresight/coresight-etm3x.c
> > @@ -363,15 +363,16 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
> >
> >       CS_UNLOCK(drvdata->base);
> >
> > +     rc = coresight_claim_device_unlocked(drvdata->base);
> > +     if (rc)
> > +             goto done;
> > +
> >       /* Turn engine on */
> >       etm_clr_pwrdwn(drvdata);
> >       /* Apply power to trace registers */
> >       etm_set_pwrup(drvdata);
> >       /* Make sure all registers are accessible */
> >       etm_os_unlock(drvdata);
> > -     rc = coresight_claim_device_unlocked(drvdata->base);
> > -     if (rc)
> > -             goto done;
> >
> >       etm_set_prog(drvdata);
> >
> > @@ -422,12 +423,11 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
> >       etm_clr_prog(drvdata);
> >
> >   done:
> > -     if (rc)
> > -             etm_set_pwrdwn(drvdata);
> >       CS_LOCK(drvdata->base);
> >
> > -     dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
> > -             drvdata->cpu, rc);
> > +     if (!rc)
> > +             dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
> > +                     drvdata->cpu, rc);
>
> Isn't it good to report the failure case too ? Anyway it is dev_dbg and
> will be a useful info when we debug issues. Otherwise,

Simply removing the "if (!rc)" will do the trick.  Can I do the
modification and add your tag or you prefer to see another revision?

>
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>
> >       return rc;
> >   }
> >
> > @@ -577,9 +577,9 @@ static void etm_disable_hw(void *info)
> >       for (i = 0; i < drvdata->nr_cntr; i++)
> >               config->cntr_val[i] = etm_readl(drvdata, ETMCNTVRn(i));
> >
> > +     etm_set_pwrdwn(drvdata);
> >       coresight_disclaim_device_unlocked(drvdata->base);
> >
> > -     etm_set_pwrdwn(drvdata);
> >       CS_LOCK(drvdata->base);
> >
> >       dev_dbg(drvdata->dev, "cpu: %d disable smp call done\n", drvdata->cpu);
> >
>

Re: [PATCH v2 3/4] coresight: etm3x: Deal with CLAIM tag before and after accessing HW

[Suzuki K Poulose]

On 11/09/2018 05:59 PM, Mathieu Poirier wrote:
> On Thu, 8 Nov 2018 at 10:13, Suzuki K Poulose <suzuki.poulose@arm.com> wrote:
>>
>> Hi,
>>
>> On 07/11/2018 23:08, Mathieu Poirier wrote:
>>> This patch moves access to the CLAIM tag so that no modification to the HW
>>> happens before and after the CLAIM operation has been carried.
>>>
>>> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>>> ---
>>>    drivers/hwtracing/coresight/coresight-etm3x.c | 16 ++++++++--------
>>>    1 file changed, 8 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
>>> index fd5c4cca7db5..4f638d81a66a 100644
>>> --- a/drivers/hwtracing/coresight/coresight-etm3x.c
>>> +++ b/drivers/hwtracing/coresight/coresight-etm3x.c
>>> @@ -363,15 +363,16 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
>>>
>>>        CS_UNLOCK(drvdata->base);
>>>
>>> +     rc = coresight_claim_device_unlocked(drvdata->base);
>>> +     if (rc)
>>> +             goto done;
>>> +
>>>        /* Turn engine on */
>>>        etm_clr_pwrdwn(drvdata);
>>>        /* Apply power to trace registers */
>>>        etm_set_pwrup(drvdata);
>>>        /* Make sure all registers are accessible */
>>>        etm_os_unlock(drvdata);
>>> -     rc = coresight_claim_device_unlocked(drvdata->base);
>>> -     if (rc)
>>> -             goto done;
>>>
>>>        etm_set_prog(drvdata);
>>>
>>> @@ -422,12 +423,11 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
>>>        etm_clr_prog(drvdata);
>>>
>>>    done:
>>> -     if (rc)
>>> -             etm_set_pwrdwn(drvdata);
>>>        CS_LOCK(drvdata->base);
>>>
>>> -     dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
>>> -             drvdata->cpu, rc);
>>> +     if (!rc)
>>> +             dev_dbg(drvdata->dev, "cpu: %d enable smp call done: %d\n",
>>> +                     drvdata->cpu, rc);
>>
>> Isn't it good to report the failure case too ? Anyway it is dev_dbg and
>> will be a useful info when we debug issues. Otherwise,
> 
> Simply removing the "if (!rc)" will do the trick.  Can I do the
> modification and add your tag or you prefer to see another revision?

I am fine with that change folded in, no need to respin it.

> 
>>
>> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>


Cheers
Suzuki


>>
>>>        return rc;
>>>    }
>>>
>>> @@ -577,9 +577,9 @@ static void etm_disable_hw(void *info)
>>>        for (i = 0; i < drvdata->nr_cntr; i++)
>>>                config->cntr_val[i] = etm_readl(drvdata, ETMCNTVRn(i));
>>>
>>> +     etm_set_pwrdwn(drvdata);
>>>        coresight_disclaim_device_unlocked(drvdata->base);
>>>
>>> -     etm_set_pwrdwn(drvdata);
>>>        CS_LOCK(drvdata->base);
>>>
>>>        dev_dbg(drvdata->dev, "cpu: %d disable smp call done\n", drvdata->cpu);
>>>
>>