drm/xe: Get GT clock to nanosecs

Helper to convert GT clock cycles to nanoseconds.

v2: Use DIV_ROUND_CLOSEST_ULL helper(Ashutosh)
v3: rename xe_gt_clock_interval_to_ns to xe_gt_clock_cycles_to_ns
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_gt_clock.c

@@ -78,3 +78,8 @@ int xe_gt_clock_init(struct xe_gt *gt)
 	gt->info.clock_freq = freq;
 	return 0;
 }
+
+u64 xe_gt_clock_cycles_to_ns(const struct xe_gt *gt, u64 count)
+{
+	return DIV_ROUND_CLOSEST_ULL(count * NSEC_PER_SEC, gt->info.clock_freq);
+}

drivers/gpu/drm/xe/xe_gt_clock.h

@@ -6,8 +6,10 @@
 #ifndef _XE_GT_CLOCK_H_
 #define _XE_GT_CLOCK_H_
 
+#include <linux/types.h>
+
 struct xe_gt;
 
 int xe_gt_clock_init(struct xe_gt *gt);
-
+u64 xe_gt_clock_cycles_to_ns(const struct xe_gt *gt, u64 count);
 #endif