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>

drivers/gpu/drm/i915/i915_gem.c

@@ -3908,7 +3908,9 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
 	 * (e.g. libkms for the bootup splash), we have to ensure that we
 	 * always use map_and_fenceable for all scanout buffers.
 	 */
-	ret = i915_gem_object_ggtt_pin(obj, view, alignment, PIN_MAPPABLE);
+	ret = i915_gem_object_ggtt_pin(obj, view, alignment,
+				       view->type == I915_GGTT_VIEW_NORMAL ?
+				       PIN_MAPPABLE : 0);
 	if (ret)
 		goto err_unpin_display;
 

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;
 }
 
 /**

drivers/gpu/drm/i915/i915_gem_gtt.h

@@ -117,12 +117,24 @@ typedef uint64_t gen8_pde_t;
 
 enum i915_ggtt_view_type {
 	I915_GGTT_VIEW_NORMAL = 0,
+	I915_GGTT_VIEW_ROTATED
+};
+
+struct intel_rotation_info {
+	unsigned int height;
+	unsigned int pitch;
+	uint32_t pixel_format;
+	uint64_t fb_modifier;
 };
 
 struct i915_ggtt_view {
 	enum i915_ggtt_view_type type;
 
 	struct sg_table *pages;
+
+	union {
+		struct intel_rotation_info rotation_info;
+	};
 };
 
 extern const struct i915_ggtt_view i915_ggtt_view_normal;

drivers/gpu/drm/i915/intel_display.c

@@ -2233,7 +2233,7 @@ static bool need_vtd_wa(struct drm_device *dev)
 	return false;
 }
 
-static unsigned int
+unsigned int
 intel_tile_height(struct drm_device *dev, uint32_t pixel_format,
 		  uint64_t fb_format_modifier)
 {
@@ -2292,8 +2292,33 @@ static int
 intel_fill_fb_ggtt_view(struct i915_ggtt_view *view, struct drm_framebuffer *fb,
 			const struct drm_plane_state *plane_state)
 {
+	struct intel_rotation_info *info = &view->rotation_info;
+	static const struct i915_ggtt_view rotated_view =
+				{ .type = I915_GGTT_VIEW_ROTATED };
+
 	*view = i915_ggtt_view_normal;
 
+	if (!plane_state)
+		return 0;
+
+	if (!(plane_state->rotation &
+	    (BIT(DRM_ROTATE_90) | BIT(DRM_ROTATE_270))))
+		return 0;
+
+	*view = rotated_view;
+
+	info->height = fb->height;
+	info->pixel_format = fb->pixel_format;
+	info->pitch = fb->pitches[0];
+	info->fb_modifier = fb->modifier[0];
+
+	if (!(info->fb_modifier == I915_FORMAT_MOD_Y_TILED ||
+	      info->fb_modifier == I915_FORMAT_MOD_Yf_TILED)) {
+		DRM_DEBUG_KMS(
+			      "Y or Yf tiling is needed for 90/270 rotation!\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }
 

drivers/gpu/drm/i915/intel_drv.h

@@ -984,6 +984,10 @@ int intel_plane_atomic_set_property(struct drm_plane *plane,
 				    struct drm_property *property,
 				    uint64_t val);
 
+unsigned int
+intel_tile_height(struct drm_device *dev, uint32_t pixel_format,
+		  uint64_t fb_format_modifier);
+
 /* shared dpll functions */
 struct intel_shared_dpll *intel_crtc_to_shared_dpll(struct intel_crtc *crtc);
 void assert_shared_dpll(struct drm_i915_private *dev_priv,