| Message ID | 1466185307-19539-1-git-send-email-mathieu.poirier@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
On 17/06/16 18:41, Mathieu Poirier wrote: > It is mandatory to enable a coresight block's power domain before > trying to access management registers. Otherwise the transaction > simply stalls, leading to a system hang. > > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> > --- > drivers/hwtracing/coresight/coresight-priv.h | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h > index ad975c58080d..b047241e7496 100644 > --- a/drivers/hwtracing/coresight/coresight-priv.h > +++ b/drivers/hwtracing/coresight/coresight-priv.h > @@ -16,6 +16,7 @@ > #include <linux/bitops.h> > #include <linux/io.h> > #include <linux/coresight.h> > +#include <linux/pm_runtime.h> > > /* > * Coresight management registers (0xf00-0xfcc) > @@ -42,8 +43,10 @@ static ssize_t name##_show(struct device *_dev, \ > struct device_attribute *attr, char *buf) \ > { \ > type *drvdata = dev_get_drvdata(_dev->parent); \ > + pm_runtime_get_sync(_dev->parent); \ > return scnprintf(buf, PAGE_SIZE, "0x%x\n", \ > readl_relaxed(drvdata->base + offset)); \ > + pm_runtime_put_sync(_dev->parent); \ This is wrong, I just noticed when I was playing around this. Perhaps you meant to do this before returning ? I wonder why compiler doesn't throw any error. -- Regards, Sudeep
On 23 June 2016 at 10:37, Sudeep Holla <sudeep.holla@arm.com> wrote: > > > On 17/06/16 18:41, Mathieu Poirier wrote: >> >> It is mandatory to enable a coresight block's power domain before >> trying to access management registers. Otherwise the transaction >> simply stalls, leading to a system hang. >> >> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> >> --- >> drivers/hwtracing/coresight/coresight-priv.h | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/hwtracing/coresight/coresight-priv.h >> b/drivers/hwtracing/coresight/coresight-priv.h >> index ad975c58080d..b047241e7496 100644 >> --- a/drivers/hwtracing/coresight/coresight-priv.h >> +++ b/drivers/hwtracing/coresight/coresight-priv.h >> @@ -16,6 +16,7 @@ >> #include <linux/bitops.h> >> #include <linux/io.h> >> #include <linux/coresight.h> >> +#include <linux/pm_runtime.h> >> >> /* >> * Coresight management registers (0xf00-0xfcc) >> @@ -42,8 +43,10 @@ static ssize_t name##_show(struct device *_dev, >> \ >> struct device_attribute *attr, char *buf) \ >> { \ >> type *drvdata = dev_get_drvdata(_dev->parent); \ >> + pm_runtime_get_sync(_dev->parent); \ >> return scnprintf(buf, PAGE_SIZE, "0x%x\n", \ >> readl_relaxed(drvdata->base + offset)); \ >> + pm_runtime_put_sync(_dev->parent); \ > > > This is wrong, I just noticed when I was playing around this. > Perhaps you meant to do this before returning ? I wonder why compiler > doesn't throw any error. Yes of course - I'll respin. > > -- > Regards, > Sudeep
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index ad975c58080d..b047241e7496 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -16,6 +16,7 @@ #include <linux/bitops.h> #include <linux/io.h> #include <linux/coresight.h> +#include <linux/pm_runtime.h> /* * Coresight management registers (0xf00-0xfcc) @@ -42,8 +43,10 @@ static ssize_t name##_show(struct device *_dev, \ struct device_attribute *attr, char *buf) \ { \ type *drvdata = dev_get_drvdata(_dev->parent); \ + pm_runtime_get_sync(_dev->parent); \ return scnprintf(buf, PAGE_SIZE, "0x%x\n", \ readl_relaxed(drvdata->base + offset)); \ + pm_runtime_put_sync(_dev->parent); \ } \ static DEVICE_ATTR_RO(name)
It is mandatory to enable a coresight block's power domain before trying to access management registers. Otherwise the transaction simply stalls, leading to a system hang. Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> --- drivers/hwtracing/coresight/coresight-priv.h | 3 +++ 1 file changed, 3 insertions(+) -- 2.5.0