[PATCH] coresight: add PM runtime calls to coresight_simple_func()

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);				\