Hi Mathieu,
On 06/03/2019 22:57, Mathieu Poirier wrote:
In preparation to handle device reference counting inside of the sink drivers, add a return code to the sink::disable() operation so that proper action can be taken if a sink has not been disabled.
Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org
drivers/hwtracing/coresight/coresight-etb10.c | 3 ++- drivers/hwtracing/coresight/coresight-tmc-etf.c | 5 +++-- drivers/hwtracing/coresight/coresight-tmc-etr.c | 5 +++-- drivers/hwtracing/coresight/coresight-tpiu.c | 3 ++- drivers/hwtracing/coresight/coresight.c | 6 +++++- include/linux/coresight.h | 2 +- 6 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c index 105782ea64c7..71c2a3cdb866 100644 --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -325,7 +325,7 @@ static void etb_disable_hw(struct etb_drvdata *drvdata) coresight_disclaim_device(drvdata->base); } -static void etb_disable(struct coresight_device *csdev) +static int etb_disable(struct coresight_device *csdev) { struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); unsigned long flags; @@ -340,6 +340,7 @@ static void etb_disable(struct coresight_device *csdev) spin_unlock_irqrestore(&drvdata->spinlock, flags); dev_dbg(drvdata->dev, "ETB disabled\n");
- return 0; }
static void *etb_alloc_buffer(struct coresight_device *csdev, int cpu, diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index a5f053f2db2c..d4213e7c2c45 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -273,7 +273,7 @@ static int tmc_enable_etf_sink(struct coresight_device *csdev, return 0; } -static void tmc_disable_etf_sink(struct coresight_device *csdev) +static int tmc_disable_etf_sink(struct coresight_device *csdev) { unsigned long flags; struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); @@ -281,7 +281,7 @@ static void tmc_disable_etf_sink(struct coresight_device *csdev) spin_lock_irqsave(&drvdata->spinlock, flags); if (drvdata->reading) { spin_unlock_irqrestore(&drvdata->spinlock, flags);
return;
return -EBUSY;
...
-static void tmc_disable_etr_sink(struct coresight_device *csdev) +static int tmc_disable_etr_sink(struct coresight_device *csdev) { unsigned long flags; struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); @@ -1400,7 +1400,7 @@ static void tmc_disable_etr_sink(struct coresight_device *csdev) spin_lock_irqsave(&drvdata->spinlock, flags); if (drvdata->reading) { spin_unlock_irqrestore(&drvdata->spinlock, flags);
return;
return -EBUSY;
This patch as such is fine. But I think we can improve the handling here.
I agree that these error codes are appropriate. However, I think we should still modify the mode to disabled for both the etf/etr to make sure the device is kept disabled after we finished reading. As the user has disabled it and thinks that it has completed successfully.
So, I think when we find that the sink buffer is being read, we may :
1) Set the mode to disabled, to allow the unprepare routine to keep this disabled.
2) Return 0, to indicate the operation will be acknowledged and no need to redo the operation.
What do you think ?
Suzuki