drm/i915/skl: Support secondary (rotated) frame buffer mapping

90/270 rotated scanout needs a rotated GTT view of the framebuffer.

This is put in a separate VMA with a dedicated ggtt view and wired such that
it is created when a framebuffer is pinned to a 90/270 rotated plane.

Rotation is only possible with Yb/Yf buffers and error is propagated to
user space in case of a mismatch.

Special rotated page view is constructed at the VMA creation time by
borrowing the DMA addresses from obj->pages.

v2:
    * Do not bother with pages for rotated sg list, just populate the DMA
      addresses. (Daniel Vetter)
    * Checkpatch cleanup.

v3:
    * Rebased on top of new plane handling (create rotated mapping when
      setting the rotation property).
    * Unpin rotated VMA on unpinning from display plane.
    * Simplify rotation check using bitwise AND. (Chris Wilson)

v4:
    * Fix unpinning of optional rotated mapping so it is really considered
      to be optional.

v5:
   * Rebased for fb modifier changes.
   * Rebased for atomic commit.
   * Only pin needed view for display. (Ville Syrjälä, Daniel Vetter)

v6:
   * Rebased after preparatory work has been extracted out. (Daniel Vetter)

v7:
   * Slightly simplified tiling geometry calculation.
   * Moved rotated GGTT view implementation into i915_gem_gtt.c (Daniel Vetter)

v8:
   * Do not use i915_gem_obj_size to get object size since that actually
     returns the size of an VMA which may not exist.
   * Rebased for ggtt view changes.

v9:
   * Rebased after code review changes on the preceding patches.
   * Tidy function definitions. (Joonas Lahtinen)

For: VIZ-4726
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com> (v4)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 113 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 645c3636c571..fc56c112a7de 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2500,15 +2500,119 @@ 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)
+{
+        unsigned int column, row;
+        unsigned int src_idx;
+        struct scatterlist *sg = st->sgl;
+
+        st->nents = 0;
+
+        for (column = 0; column < width; column++) {
+                src_idx = width * (height - 1) + column;
+                for (row = 0; row < height; row++) {
+                        st->nents++;
+                        /* We don't need the pages, but need to initialize
+                         * the entries so the sg list can be happily traversed.
+                         * 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_len(sg) = PAGE_SIZE;
+                        sg = sg_next(sg);
+                        src_idx -= width;
+                }
+        }
+}
+
+static struct sg_table *
+intel_rotate_fb_obj_pages(struct i915_ggtt_view *ggtt_view,
+                          struct drm_i915_gem_object *obj)
+{
+        struct drm_device *dev = obj->base.dev;
+        struct intel_rotation_info *rot_info = &ggtt_view->rotation_info;
+        unsigned long size, pages, rot_pages;
+        struct sg_page_iter sg_iter;
+        unsigned long i;
+        dma_addr_t *page_addr_list;
+        struct sg_table *st;
+        unsigned int tile_pitch, tile_height;
+        unsigned int width_pages, height_pages;
+        int ret = ENOMEM;
+
+        pages = obj->base.size / PAGE_SIZE;
+
+        /* Calculate tiling geometry. */
+        tile_height = intel_tile_height(dev, rot_info->pixel_format,
+                                        rot_info->fb_modifier);
+        tile_pitch = PAGE_SIZE / tile_height;
+        width_pages = DIV_ROUND_UP(rot_info->pitch, tile_pitch);
+        height_pages = DIV_ROUND_UP(rot_info->height, tile_height);
+        rot_pages = width_pages * height_pages;
+        size = rot_pages * PAGE_SIZE;
+
+        /* Allocate a temporary list of source pages for random access. */
+        page_addr_list = drm_malloc_ab(pages, sizeof(dma_addr_t));
+        if (!page_addr_list)
+                return ERR_PTR(ret);
+
+        /* Allocate target SG list. */
+        st = kmalloc(sizeof(*st), GFP_KERNEL);
+        if (!st)
+                goto err_st_alloc;
+
+        ret = sg_alloc_table(st, rot_pages, GFP_KERNEL);
+        if (ret)
+                goto err_sg_alloc;
+
+        /* Populate source page list from the object. */
+        i = 0;
+        for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) {
+                page_addr_list[i] = sg_page_iter_dma_address(&sg_iter);
+                i++;
+        }
+
+        /* Rotate the pages. */
+        rotate_pages(page_addr_list, width_pages, height_pages, st);
+
+        DRM_DEBUG_KMS(
+                      "Created rotated page mapping for object size %lu (pitch=%u, height=%u, pixel_format=0x%x, %ux%u tiles, %lu pages).\n",
+                      size, rot_info->pitch, rot_info->height,
+                      rot_info->pixel_format, width_pages, height_pages,
+                      rot_pages);
+
+        drm_free_large(page_addr_list);
+
+        return st;
+
+err_sg_alloc:
+        kfree(st);
+err_st_alloc:
+        drm_free_large(page_addr_list);
+
+        DRM_DEBUG_KMS(
+                      "Failed to create rotated mapping for object size %lu! (%d) (pitch=%u, height=%u, pixel_format=0x%x, %ux%u tiles, %lu pages)\n",
+                      size, ret, rot_info->pitch, rot_info->height,
+                      rot_info->pixel_format, width_pages, height_pages,
+                      rot_pages);
+        return ERR_PTR(ret);
+}
 
-static inline
-int i915_get_ggtt_vma_pages(struct i915_vma *vma)
+static inline int
+i915_get_ggtt_vma_pages(struct i915_vma *vma)
 {
+        int ret = 0;
+
         if (vma->ggtt_view.pages)
                 return 0;
 
         if (vma->ggtt_view.type == I915_GGTT_VIEW_NORMAL)
                 vma->ggtt_view.pages = vma->obj->pages;
+        else if (vma->ggtt_view.type == I915_GGTT_VIEW_ROTATED)
+                vma->ggtt_view.pages =
+                        intel_rotate_fb_obj_pages(&vma->ggtt_view, vma->obj);
         else
                 WARN_ONCE(1, "GGTT view %u not implemented!\n",
                           vma->ggtt_view.type);
@@ -2516,10 +2620,15 @@ int i915_get_ggtt_vma_pages(struct i915_vma *vma)
         if (!vma->ggtt_view.pages) {
                 DRM_ERROR("Failed to get pages for GGTT view type %u!\n",
                           vma->ggtt_view.type);
-                return -EINVAL;
+                ret = -EINVAL;
+        } else if (IS_ERR(vma->ggtt_view.pages)) {
+                ret = PTR_ERR(vma->ggtt_view.pages);
+                vma->ggtt_view.pages = NULL;
+                DRM_ERROR("Failed to get pages for VMA view type %u (%d)!\n",
+                          vma->ggtt_view.type, ret);
         }
 
-        return 0;
+        return ret;
 }
 
 /**