drm/i915: Use a common function for computing the fb height alignment

If we need to change the fb height constraints, it sounds like a good
idea to have to do it in one place only.

v2: v2: Rebase on top of Ander's "Make intel_crtc->config a pointer"

Reviewed-By: Tvrtko Ursulin <tvrtko.ursulin@intel.com> (v1)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 98cd20a..91954ff 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2188,11 +2188,12 @@
 	return false;
 }
 
-static int intel_align_height(struct drm_device *dev, int height, bool tiled)
+int
+intel_fb_align_height(struct drm_device *dev, int height, unsigned int tiling)
 {
 	int tile_height;
 
-	tile_height = tiled ? (IS_GEN2(dev) ? 16 : 8) : 1;
+	tile_height = tiling ? (IS_GEN2(dev) ? 16 : 8) : 1;
 	return ALIGN(height, tile_height);
 }
 
@@ -6590,8 +6591,9 @@
 	val = I915_READ(DSPSTRIDE(pipe));
 	crtc->base.primary->fb->pitches[0] = val & 0xffffffc0;
 
-	aligned_height = intel_align_height(dev, crtc->base.primary->fb->height,
-					    plane_config->tiling);
+	aligned_height = intel_fb_align_height(dev,
+					       crtc->base.primary->fb->height,
+					       plane_config->tiling);
 
 	plane_config->size = PAGE_ALIGN(crtc->base.primary->fb->pitches[0] *
 					aligned_height);
@@ -7644,8 +7646,9 @@
 	val = I915_READ(DSPSTRIDE(pipe));
 	crtc->base.primary->fb->pitches[0] = val & 0xffffffc0;
 
-	aligned_height = intel_align_height(dev, crtc->base.primary->fb->height,
-					    plane_config->tiling);
+	aligned_height = intel_fb_align_height(dev,
+					       crtc->base.primary->fb->height,
+					       plane_config->tiling);
 
 	plane_config->size = PAGE_ALIGN(crtc->base.primary->fb->pitches[0] *
 					aligned_height);
@@ -12609,8 +12612,8 @@
 	if (mode_cmd->offsets[0] != 0)
 		return -EINVAL;
 
-	aligned_height = intel_align_height(dev, mode_cmd->height,
-					    obj->tiling_mode);
+	aligned_height = intel_fb_align_height(dev, mode_cmd->height,
+					       obj->tiling_mode);
 	/* FIXME drm helper for size checks (especially planar formats)? */
 	if (obj->base.size < aligned_height * mode_cmd->pitches[0])
 		return -EINVAL;