[RFC PATCH 6/7] drm/i915: add range busy check for ttm region

[Robert Beckett <bob.beckett@collabora.com>]

RFC: should this become a generic interface in intel_memory_region_ops?

RFC: would we prefer an different interface? e.g. for_each_obj_in_range

Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
---
 drivers/gpu/drm/i915/intel_region_ttm.c | 19 +++++++++++++++++++
 drivers/gpu/drm/i915/intel_region_ttm.h |  3 +++
 2 files changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_region_ttm.c b/drivers/gpu/drm/i915/intel_region_ttm.c
index bb564b830c96..2ccefa76348f 100644
--- a/drivers/gpu/drm/i915/intel_region_ttm.c
+++ b/drivers/gpu/drm/i915/intel_region_ttm.c
@@ -256,3 +256,22 @@ void intel_region_ttm_resource_free(struct intel_memory_region *mem,
 
 	man->func->free(man, res);
 }
+
+/**
+ * intel_region_ttm_range_busy - check whether range has any allocations
+ * @mem: The region to check
+ * @start: the start of the range to check
+ * @end: the end of the range to check
+ *
+ * Return: true if something is alloceted within the region, false otherwise.
+ */
+bool intel_region_ttm_range_busy(struct intel_memory_region *mem,
+				 u64 start, u64 end)
+{
+	struct ttm_resource_manager *man = mem->region_private;
+
+	/* currently only supported for range allocator */
+	GEM_BUG_ON(!mem->is_range_manager);
+
+	return ttm_range_man_range_busy(man, PFN_DOWN(start), PFN_UP(end));
+}
diff --git a/drivers/gpu/drm/i915/intel_region_ttm.h b/drivers/gpu/drm/i915/intel_region_ttm.h
index fdee5e7bd46c..670ba9b618f7 100644
--- a/drivers/gpu/drm/i915/intel_region_ttm.h
+++ b/drivers/gpu/drm/i915/intel_region_ttm.h
@@ -29,6 +29,9 @@ intel_region_ttm_resource_to_rsgt(struct intel_memory_region *mem,
 void intel_region_ttm_resource_free(struct intel_memory_region *mem,
 				    struct ttm_resource *res);
 
+bool intel_region_ttm_range_busy(struct intel_memory_region *mem,
+				 u64 start, u64 end);
+
 int intel_region_to_ttm_type(const struct intel_memory_region *mem);
 
 struct ttm_device_funcs *i915_ttm_driver(void);
-- 
2.25.1