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>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index ad975c58080d..decfd52b5dc3 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 +43,11 @@ static ssize_t name##_show(struct device *_dev,				\
                            struct device_attribute *attr, char *buf)    \
 {                                                                       \
         type *drvdata = dev_get_drvdata(_dev->parent);                  \
-        return scnprintf(buf, PAGE_SIZE, "0x%x\n",                      \
-                         readl_relaxed(drvdata->base + offset));        \
+        u32 val;                                                        \
+        pm_runtime_get_sync(_dev->parent);                              \
+        val = readl_relaxed(drvdata->base + offset);                    \
+        pm_runtime_put_sync(_dev->parent);                              \
+        return scnprintf(buf, PAGE_SIZE, "0x%x\n", val);                \
 }                                                                       \
 static DEVICE_ATTR_RO(name)