drm/radeon/kms: implement timestamp userspace query (v2)

Returns a snapshot of the GPU clock counter.  Needed
for certain OpenGL extensions.

v2: agd5f
- address Jerome's comments
- add function documentation

Signed-off-by: Marek Olšák <maraeo@gmail.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_asic.h b/drivers/gpu/drm/radeon/radeon_asic.h
index 0d445e7..18c38d1 100644
--- a/drivers/gpu/drm/radeon/radeon_asic.h
+++ b/drivers/gpu/drm/radeon/radeon_asic.h
@@ -368,6 +368,7 @@
 			unsigned num_gpu_pages,
 			struct radeon_sa_bo *vb);
 int r600_mc_wait_for_idle(struct radeon_device *rdev);
+uint64_t r600_get_gpu_clock(struct radeon_device *rdev);
 
 /*
  * rv770,rv730,rv710,rv740
@@ -468,5 +469,6 @@
 void si_vm_unbind(struct radeon_device *rdev, struct radeon_vm *vm);
 void si_vm_tlb_flush(struct radeon_device *rdev, struct radeon_vm *vm);
 int si_ib_parse(struct radeon_device *rdev, struct radeon_ib *ib);
+uint64_t si_get_gpu_clock(struct radeon_device *rdev);
 
 #endif