[PATCH v4 3/8] drm/i915/display: Add a disable_tiling() for skl planes

[Jocelyn Falempe <jfalempe@redhat.com>]

drm_panic draws in linear framebuffer, so it's easier to re-use the
current framebuffer, and disable tiling in the panic handler, to show
the panic screen.

Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
---
 .../drm/i915/display/skl_universal_plane.c    | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
index ff9764cac1e71..7cc5f8e700e7e 100644
--- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
+++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
@@ -2603,6 +2603,25 @@ static u8 skl_get_plane_caps(struct drm_i915_private *i915,
 	return caps;
 }
 
+static void skl_disable_tiling(struct intel_plane *plane)
+{
+	u32 plane_ctl;
+	struct intel_plane_state *state = to_intel_plane_state(plane->base.state);
+	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
+	u32 stride = state->view.color_plane[0].scanout_stride / 64;
+
+	plane_ctl = intel_de_read(dev_priv, PLANE_CTL(plane->pipe, plane->id));
+	plane_ctl &= ~PLANE_CTL_TILED_MASK;
+
+	intel_de_write_fw(dev_priv, PLANE_STRIDE(plane->pipe, plane->id),
+			  PLANE_STRIDE_(stride));
+
+	intel_de_write_fw(dev_priv, PLANE_CTL(plane->pipe, plane->id), plane_ctl);
+
+	intel_de_write_fw(dev_priv, PLANE_SURF(plane->pipe, plane->id),
+			  skl_plane_surf(state, 0));
+}
+
 struct intel_plane *
 skl_universal_plane_create(struct drm_i915_private *dev_priv,
 			   enum pipe pipe, enum plane_id plane_id)
@@ -2648,6 +2667,7 @@ skl_universal_plane_create(struct drm_i915_private *dev_priv,
 		plane->max_height = skl_plane_max_height;
 		plane->min_cdclk = skl_plane_min_cdclk;
 	}
+	plane->disable_tiling = skl_disable_tiling;
 
 	if (DISPLAY_VER(dev_priv) >= 13)
 		plane->max_stride = adl_plane_max_stride;
-- 
2.47.1