drm/i915/gen11: Link nv12 Y and UV planes in the atomic state, v5.

To make NV12 working on icl, we need to update 2 planes simultaneously.
I've chosen to do this in the CRTC step after plane validation is done,
so we know what planes are (in)visible. The linked Y plane will get
updated in intel_plane_update_planes_on_crtc(), by the call to
update_slave, which gets the master's plane_state as argument.

The link requires both planes for atomic_update to work,
so make sure skl_ddb_add_affected_planes() adds both states.

Changes since v1:
- Introduce icl_is_nv12_y_plane(), instead of hardcoding sprite numbers.
- Put all the state updating login in intel_plane_atomic_check_with_state().
- Clean up changes in intel_plane_atomic_check().
Changes since v2:
- Fix intel_atomic_get_old_plane_state() to actually return old state.
- Move visibility changes to preparation patch.
- Only try to find a Y plane on gen11, earlier platforms only require
  a single plane.
Changes since v3:
- Fix checkpatch warning about to_intel_crtc() usage.
- Add affected planes from icl_add_linked_planes() before check_planes(),
  it's a cleaner way to do this. (Ville)
Changes since v4:
- Clear plane links in icl_check_nv12_planes() for clarity.
- Only pass crtc_state to icl_check_nv12_planes().
- Use for_each_new_intel_plane_in_state() in icl_check_nv12_planes.
- Rename aux to linked. (Ville)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181022135152.15324-1-maarten.lankhorst@linux.intel.com
[mlankhorst: Change bool slave to u32, to satisfy checkpatch]
[mlankhorst: Add WARN_ON's based on Ville's suggestion]

drivers/gpu/drm/i915/intel_drv.h

@@ -539,6 +539,26 @@ struct intel_plane_state {
 	 */
 	int scaler_id;
 
+	/*
+	 * linked_plane:
+	 *
+	 * ICL planar formats require 2 planes that are updated as pairs.
+	 * This member is used to make sure the other plane is also updated
+	 * when required, and for update_slave() to find the correct
+	 * plane_state to pass as argument.
+	 */
+	struct intel_plane *linked_plane;
+
+	/*
+	 * slave:
+	 * If set don't update use the linked plane's state for updating
+	 * this plane during atomic commit with the update_slave() callback.
+	 *
+	 * It's also used by the watermark code to ignore wm calculations on
+	 * this plane. They're calculated by the linked plane's wm code.
+	 */
+	u32 slave;
+
 	struct drm_intel_sprite_colorkey ckey;
 };
 
@@ -983,6 +1003,9 @@ struct intel_plane {
 	void (*update_plane)(struct intel_plane *plane,
 			     const struct intel_crtc_state *crtc_state,
 			     const struct intel_plane_state *plane_state);
+	void (*update_slave)(struct intel_plane *plane,
+			     const struct intel_crtc_state *crtc_state,
+			     const struct intel_plane_state *plane_state);
 	void (*disable_plane)(struct intel_plane *plane,
 			      struct intel_crtc *crtc);
 	bool (*get_hw_state)(struct intel_plane *plane, enum pipe *pipe);
@@ -1357,6 +1380,27 @@ hdmi_to_dig_port(struct intel_hdmi *intel_hdmi)
 	return container_of(intel_hdmi, struct intel_digital_port, hdmi);
 }
 
+static inline struct intel_plane_state *
+intel_atomic_get_plane_state(struct intel_atomic_state *state,
+				 struct intel_plane *plane)
+{
+	struct drm_plane_state *ret =
+		drm_atomic_get_plane_state(&state->base, &plane->base);
+
+	if (IS_ERR(ret))
+		return ERR_CAST(ret);
+
+	return to_intel_plane_state(ret);
+}
+
+static inline struct intel_plane_state *
+intel_atomic_get_old_plane_state(struct intel_atomic_state *state,
+				 struct intel_plane *plane)
+{
+	return to_intel_plane_state(drm_atomic_get_old_plane_state(&state->base,
+								   &plane->base));
+}
+
 static inline struct intel_plane_state *
 intel_atomic_get_new_plane_state(struct intel_atomic_state *state,
 				 struct intel_plane *plane)
@@ -2165,6 +2209,15 @@ struct intel_plane *
 skl_universal_plane_create(struct drm_i915_private *dev_priv,
 			   enum pipe pipe, enum plane_id plane_id);
 
+static inline bool icl_is_nv12_y_plane(enum plane_id id)
+{
+	/* Don't need to do a gen check, these planes are only available on gen11 */
+	if (id == PLANE_SPRITE4 || id == PLANE_SPRITE5)
+		return true;
+
+	return false;
+}
+
 /* intel_tv.c */
 void intel_tv_init(struct drm_i915_private *dev_priv);