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Commit 341be1cd authored by Chris Wilson's avatar Chris Wilson Committed by Tvrtko Ursulin
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drm/i915: Introduce i915_gem_object_get_dma_address() 



This utility function is a companion to i915_gem_object_get_page() that
uses the same cached iterator for the scatterlist to perform fast
sequential lookup of the dma address associated with any page within the
object.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarAnkitprasad Sharma <ankitprasad.r.sharma@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
parent d6473f56

drivers/gpu/drm/i915/i915_drv.h

+17 −0
Original line number Diff line number Diff line
@@ -3118,6 +3118,23 @@ static inline int __sg_page_count(struct scatterlist *sg) 
struct page *

i915_gem_object_get_dirty_page(struct drm_i915_gem_object *obj, int n);



static inline dma_addr_t

i915_gem_object_get_dma_address(struct drm_i915_gem_object *obj, int n)

{

	if (n < obj->get_page.last) {

		obj->get_page.sg = obj->pages->sgl;

		obj->get_page.last = 0;

	}



	while (obj->get_page.last + __sg_page_count(obj->get_page.sg) <= n) {

		obj->get_page.last += __sg_page_count(obj->get_page.sg++);

		if (unlikely(sg_is_chain(obj->get_page.sg)))

			obj->get_page.sg = sg_chain_ptr(obj->get_page.sg);

	}



	return sg_dma_address(obj->get_page.sg) + ((n - obj->get_page.last) << PAGE_SHIFT);

}



static inline struct page *

i915_gem_object_get_page(struct drm_i915_gem_object *obj, int n)

{