drm/i915: Support appending to the rotated pages mapping

By providing a start offset into the source array of pages, and returning the
end position in the scatter-gather table, we will be able to append the UV
plane to the rotated mapping in later patches.

v2: Rebase.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 01f3521e77d35bb0d7e5b390a250225b4cb3f8be..2a8f64dc509678a5b9c89201aa0174392ab47c9a 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3244,15 +3244,18 @@ i915_gem_obj_lookup_or_create_ggtt_vma(struct drm_i915_gem_object *obj,
 
 }
 
-static void
-rotate_pages(dma_addr_t *in, unsigned int width, unsigned int height,
-            struct sg_table *st)
+static struct scatterlist *
+rotate_pages(dma_addr_t *in, unsigned int offset,
+            unsigned int width, unsigned int height,
+            struct sg_table *st, struct scatterlist *sg)
 {
        unsigned int column, row;
        unsigned int src_idx;
-       struct scatterlist *sg = st->sgl;
 
-       st->nents = 0;
+       if (!sg) {
+               st->nents = 0;
+               sg = st->sgl;
+       }
 
        for (column = 0; column < width; column++) {
                src_idx = width * (height - 1) + column;
@@ -3263,12 +3266,14 @@ rotate_pages(dma_addr_t *in, unsigned int width, unsigned int height,
                         * The only thing we need are DMA addresses.
                         */
                        sg_set_page(sg, NULL, PAGE_SIZE, 0);
-                       sg_dma_address(sg) = in[src_idx];
+                       sg_dma_address(sg) = in[offset + src_idx];
                        sg_dma_len(sg) = PAGE_SIZE;
                        sg = sg_next(sg);
                        src_idx -= width;
                }
        }
+
+       return sg;
 }
 
 static struct sg_table *
@@ -3306,9 +3311,9 @@ intel_rotate_fb_obj_pages(struct i915_ggtt_view *ggtt_view,
        }
 
        /* Rotate the pages. */
-       rotate_pages(page_addr_list,
+       rotate_pages(page_addr_list, 0,
                     rot_info->width_pages, rot_info->height_pages,
-                    st);
+                    st, NULL);
 
        DRM_DEBUG_KMS(
                      "Created rotated page mapping for object size %zu (pitch=%u, height=%u, pixel_format=0x%x, %ux%u tiles, %u pages).\n",