Hi Suzuki,
I have starte to review this - comments will be scattered over a few days.
On Wed, Jul 22, 2020 at 06:20:27PM +0100, Suzuki K Poulose wrote:
Skip cpu save/restore before the coresight device is registered.
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
drivers/hwtracing/coresight/coresight-etm4x.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 6d7d2169bfb2..cb83fb77ded6 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -1135,7 +1135,13 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
{
int i, ret = 0;
struct etmv4_save_state *state;
- struct device *etm_dev = &drvdata->csdev->dev;
+ struct coresight_device *csdev = drvdata->csdev;
+ struct device *etm_dev;
+
+ if (WARN_ON(!csdev))
+ return -ENODEV;
+
+ etm_dev = &csdev->dev;
/*
* As recommended by 3.4.1 ("The procedure when powering down the PE")
@@ -1261,6 +1267,10 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
{
int i;
struct etmv4_save_state *state = drvdata->save_state;
+ struct coresight_device *csdev = drvdata->csdev;
+
+ if (WARN_ON(!csdev))
+ return;
Restore and save operations are only called from etm4_cpu_pm_notify() where the
check for a valid drvdata->csdev is already done.
CS_UNLOCK(drvdata->base);
@@ -1368,6 +1378,10 @@ static int etm4_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd,
drvdata = etmdrvdata[cpu];
+ /* If we have not registered the device there is nothing to do */
+ if (!drvdata->csdev)
+ return NOTIFY_OK;
Can you describe the scenario you've seen this happening in? Probably best to
add it to the changelog.