drm/i915: Reorganize WM structs/unions in CRTC state

Reorganize the nested structures and unions we have for pipe watermark
data in intel_crtc_state so that platform-specific data can be added in
a more sensible manner (and save a bit of memory at the same time).

The change basically changes the organization from:

        union {
                struct intel_pipe_wm ilk;
                struct intel_pipe_wm skl;
        } optimal;

        struct intel_pipe_wm intermediate /* ILK-only */

to

        union {
                struct {
                        struct intel_pipe_wm intermediate;
                        struct intel_pipe_wm optimal;
                } ilk;

                struct {
                        struct intel_pipe_wm optimal;
                } skl;
        }

There should be no functional change here, but it will allow us to add
more platform-specific fields going forward (and more easily extend to
other platform types like VLV).

While we're at it, let's move the entire watermark substructure out to
its own structure definition to make the code slightly more readable.
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-2-git-send-email-matthew.d.roper@intel.com

drivers/gpu/drm/i915/intel_drv.h

@@ -405,6 +405,40 @@ struct skl_pipe_wm {
 	uint32_t linetime;
 };
 
+struct intel_crtc_wm_state {
+	union {
+		struct {
+			/*
+			 * Intermediate watermarks; these can be
+			 * programmed immediately since they satisfy
+			 * both the current configuration we're
+			 * switching away from and the new
+			 * configuration we're switching to.
+			 */
+			struct intel_pipe_wm intermediate;
+
+			/*
+			 * Optimal watermarks, programmed post-vblank
+			 * when this state is committed.
+			 */
+			struct intel_pipe_wm optimal;
+		} ilk;
+
+		struct {
+			/* gen9+ only needs 1-step wm programming */
+			struct skl_pipe_wm optimal;
+		} skl;
+	};
+
+	/*
+	 * Platforms with two-step watermark programming will need to
+	 * update watermark programming post-vblank to switch from the
+	 * safe intermediate watermarks to the optimal final
+	 * watermarks.
+	 */
+	bool need_postvbl_update;
+};
+
 struct intel_crtc_state {
 	struct drm_crtc_state base;
 
@@ -558,32 +592,7 @@ struct intel_crtc_state {
 	/* IVB sprite scaling w/a (WaCxSRDisabledForSpriteScaling:ivb) */
 	bool disable_lp_wm;
 
-	struct {
-		/*
-		 * Optimal watermarks, programmed post-vblank when this state
-		 * is committed.
-		 */
-		union {
-			struct intel_pipe_wm ilk;
-			struct skl_pipe_wm skl;
-		} optimal;
-
-		/*
-		 * Intermediate watermarks; these can be programmed immediately
-		 * since they satisfy both the current configuration we're
-		 * switching away from and the new configuration we're switching
-		 * to.
-		 */
-		struct intel_pipe_wm intermediate;
-
-		/*
-		 * Platforms with two-step watermark programming will need to
-		 * update watermark programming post-vblank to switch from the
-		 * safe intermediate watermarks to the optimal final
-		 * watermarks.
-		 */
-		bool need_postvbl_update;
-	} wm;
+	struct intel_crtc_wm_state wm;
 
 	/* Gamma mode programmed on the pipe */
 	uint32_t gamma_mode;

drivers/gpu/drm/i915/intel_pm.c

@@ -2309,7 +2309,7 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
 	int level, max_level = ilk_wm_max_level(dev), usable_level;
 	struct ilk_wm_maximums max;
 
-	pipe_wm = &cstate->wm.optimal.ilk;
+	pipe_wm = &cstate->wm.ilk.optimal;
 
 	for_each_intel_plane_on_crtc(dev, intel_crtc, intel_plane) {
 		struct intel_plane_state *ps;
@@ -2391,7 +2391,7 @@ static int ilk_compute_intermediate_wm(struct drm_device *dev,
 				       struct intel_crtc *intel_crtc,
 				       struct intel_crtc_state *newstate)
 {
-	struct intel_pipe_wm *a = &newstate->wm.intermediate;
+	struct intel_pipe_wm *a = &newstate->wm.ilk.intermediate;
 	struct intel_pipe_wm *b = &intel_crtc->wm.active.ilk;
 	int level, max_level = ilk_wm_max_level(dev);
 
@@ -2400,7 +2400,7 @@ static int ilk_compute_intermediate_wm(struct drm_device *dev,
 	 * currently active watermarks to get values that are safe both before
 	 * and after the vblank.
 	 */
-	*a = newstate->wm.optimal.ilk;
+	*a = newstate->wm.ilk.optimal;
 	a->pipe_enabled |= b->pipe_enabled;
 	a->sprites_enabled |= b->sprites_enabled;
 	a->sprites_scaled |= b->sprites_scaled;
@@ -2429,7 +2429,7 @@ static int ilk_compute_intermediate_wm(struct drm_device *dev,
 	 * If our intermediate WM are identical to the final WM, then we can
 	 * omit the post-vblank programming; only update if it's different.
 	 */
-	if (memcmp(a, &newstate->wm.optimal.ilk, sizeof(*a)) == 0)
+	if (memcmp(a, &newstate->wm.ilk.optimal, sizeof(*a)) == 0)
 		newstate->wm.need_postvbl_update = false;
 
 	return 0;
@@ -3678,7 +3678,7 @@ static void skl_update_wm(struct drm_crtc *crtc)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct skl_wm_values *results = &dev_priv->wm.skl_results;
 	struct intel_crtc_state *cstate = to_intel_crtc_state(crtc->state);
-	struct skl_pipe_wm *pipe_wm = &cstate->wm.optimal.skl;
+	struct skl_pipe_wm *pipe_wm = &cstate->wm.skl.optimal;
 
 
 	/* Clear all dirty flags */
@@ -3757,7 +3757,7 @@ static void ilk_initial_watermarks(struct intel_crtc_state *cstate)
 	struct intel_crtc *intel_crtc = to_intel_crtc(cstate->base.crtc);
 
 	mutex_lock(&dev_priv->wm.wm_mutex);
-	intel_crtc->wm.active.ilk = cstate->wm.intermediate;
+	intel_crtc->wm.active.ilk = cstate->wm.ilk.intermediate;
 	ilk_program_watermarks(dev_priv);
 	mutex_unlock(&dev_priv->wm.wm_mutex);
 }
@@ -3769,7 +3769,7 @@ static void ilk_optimize_watermarks(struct intel_crtc_state *cstate)
 
 	mutex_lock(&dev_priv->wm.wm_mutex);
 	if (cstate->wm.need_postvbl_update) {
-		intel_crtc->wm.active.ilk = cstate->wm.optimal.ilk;
+		intel_crtc->wm.active.ilk = cstate->wm.ilk.optimal;
 		ilk_program_watermarks(dev_priv);
 	}
 	mutex_unlock(&dev_priv->wm.wm_mutex);
@@ -3826,7 +3826,7 @@ static void skl_pipe_wm_get_hw_state(struct drm_crtc *crtc)
 	struct skl_wm_values *hw = &dev_priv->wm.skl_hw;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct intel_crtc_state *cstate = to_intel_crtc_state(crtc->state);
-	struct skl_pipe_wm *active = &cstate->wm.optimal.skl;
+	struct skl_pipe_wm *active = &cstate->wm.skl.optimal;
 	enum pipe pipe = intel_crtc->pipe;
 	int level, i, max_level;
 	uint32_t temp;
@@ -3892,7 +3892,7 @@ static void ilk_pipe_wm_get_hw_state(struct drm_crtc *crtc)
 	struct ilk_wm_values *hw = &dev_priv->wm.hw;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct intel_crtc_state *cstate = to_intel_crtc_state(crtc->state);
-	struct intel_pipe_wm *active = &cstate->wm.optimal.ilk;
+	struct intel_pipe_wm *active = &cstate->wm.ilk.optimal;
 	enum pipe pipe = intel_crtc->pipe;
 	static const i915_reg_t wm0_pipe_reg[] = {
 		[PIPE_A] = WM0_PIPEA_ILK,