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.poir...@linaro.org>
> Cc: Mike Leach <mike.le...@linaro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com>
> ---
> 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.
> +
> if (!drvdata->save_state)
> return NOTIFY_OK;
>
> --
> 2.24.1
>
