drm/i915: Calculate ILK-style watermarks during atomic check (v3)

Calculate pipe watermarks during atomic calculation phase, based on the
contents of the atomic transaction's state structure.  We still program
the watermarks at the same time we did before, but the computation now
happens much earlier.

While this patch isn't too exciting by itself, it paves the way for
future patches.  The eventual goal (which will be realized in future
patches in this series) is to calculate multiple sets up watermark
values up front, and then program them at different times (pre- vs
post-vblank) on the platforms that need a two-step watermark update.

While we're at it, s/intel_compute_pipe_wm/ilk_compute_pipe_wm/ since
this function only applies to ILK-style watermarks and we have a
completely different function for SKL-style watermarks.

Note that the original code had a memcmp() in ilk_update_wm() to avoid
calling ilk_program_watermarks() if the watermarks hadn't changed.  This
memcmp vanishes here, which means we may do some unnecessary result
generation and merging in cases where watermarks didn't change, but the
lower-level function ilk_write_wm_values already makes sure that we
don't actually try to program the watermark registers again.

v2: Squash a few commits from the original series together; no longer
    leave pre-calculated wm's in a separate temporary structure since
    it's easier to follow the logic if we just cut over to using the
    pre-calculated values directly.

v3:
 - Pass intel_crtc instead of drm_crtc to .compute_pipe_wm() entrypoint
   and use intel_atomic_get_crtc_state() to avoid need for extra
   casting.  (Ander)
 - Drop unused intel_check_crtc() function prototype.  (Ander)

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Smoke-tested-by: Paulo Zanoni <przanoni@gmail.com>
Link: http://patchwork.freedesktop.org/patch/60363/

drivers/gpu/drm/i915/i915_drv.h

@@ -627,6 +627,8 @@ struct drm_i915_display_funcs {
 			  int target, int refclk,
 			  struct dpll *match_clock,
 			  struct dpll *best_clock);
+	int (*compute_pipe_wm)(struct intel_crtc *crtc,
+			       struct drm_atomic_state *state);
 	void (*update_wm)(struct drm_crtc *crtc);
 	int (*modeset_calc_cdclk)(struct drm_atomic_state *state);
 	void (*modeset_commit_cdclk)(struct drm_atomic_state *state);

drivers/gpu/drm/i915/intel_display.c

@@ -11827,6 +11827,12 @@ static int intel_crtc_atomic_check(struct drm_crtc *crtc,
 	}
 
 	ret = 0;
+	if (dev_priv->display.compute_pipe_wm) {
+		ret = dev_priv->display.compute_pipe_wm(intel_crtc, state);
+		if (ret)
+			return ret;
+	}
+
 	if (INTEL_INFO(dev)->gen >= 9) {
 		if (mode_changed)
 			ret = skl_update_scaler_crtc(pipe_config);

drivers/gpu/drm/i915/intel_pm.c

@@ -1972,9 +1972,11 @@ static void ilk_compute_wm_level(const struct drm_i915_private *dev_priv,
 				 const struct intel_crtc *intel_crtc,
 				 int level,
 				 struct intel_crtc_state *cstate,
+				 struct intel_plane_state *pristate,
+				 struct intel_plane_state *sprstate,
+				 struct intel_plane_state *curstate,
 				 struct intel_wm_level *result)
 {
-	struct intel_plane *intel_plane;
 	uint16_t pri_latency = dev_priv->wm.pri_latency[level];
 	uint16_t spr_latency = dev_priv->wm.spr_latency[level];
 	uint16_t cur_latency = dev_priv->wm.cur_latency[level];
@@ -1986,29 +1988,11 @@ static void ilk_compute_wm_level(const struct drm_i915_private *dev_priv,
 		cur_latency *= 5;
 	}
 
-	for_each_intel_plane_on_crtc(dev_priv->dev, intel_crtc, intel_plane) {
-		struct intel_plane_state *pstate =
-			to_intel_plane_state(intel_plane->base.state);
-
-		switch (intel_plane->base.type) {
-		case DRM_PLANE_TYPE_PRIMARY:
-			result->pri_val = ilk_compute_pri_wm(cstate, pstate,
-							     pri_latency,
-							     level);
-			result->fbc_val = ilk_compute_fbc_wm(cstate, pstate,
-							     result->pri_val);
-			break;
-		case DRM_PLANE_TYPE_OVERLAY:
-			result->spr_val = ilk_compute_spr_wm(cstate, pstate,
-							     spr_latency);
-			break;
-		case DRM_PLANE_TYPE_CURSOR:
-			result->cur_val = ilk_compute_cur_wm(cstate, pstate,
-							     cur_latency);
-			break;
-		}
-	}
-
+	result->pri_val = ilk_compute_pri_wm(cstate, pristate,
+					     pri_latency, level);
+	result->spr_val = ilk_compute_spr_wm(cstate, sprstate, spr_latency);
+	result->cur_val = ilk_compute_cur_wm(cstate, curstate, cur_latency);
+	result->fbc_val = ilk_compute_fbc_wm(cstate, pristate, result->pri_val);
 	result->enable = true;
 }
 
@@ -2286,15 +2270,18 @@ static void ilk_compute_wm_config(struct drm_device *dev,
 }
 
 /* Compute new watermarks for the pipe */
-static bool intel_compute_pipe_wm(struct intel_crtc_state *cstate,
-				  struct intel_pipe_wm *pipe_wm)
+static int ilk_compute_pipe_wm(struct intel_crtc *intel_crtc,
+			       struct drm_atomic_state *state)
 {
-	struct drm_crtc *crtc = cstate->base.crtc;
-	struct drm_device *dev = crtc->dev;
+	struct intel_pipe_wm *pipe_wm;
+	struct drm_device *dev = intel_crtc->base.dev;
 	const struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	struct intel_crtc_state *cstate = NULL;
 	struct intel_plane *intel_plane;
+	struct drm_plane_state *ps;
+	struct intel_plane_state *pristate = NULL;
 	struct intel_plane_state *sprstate = NULL;
+	struct intel_plane_state *curstate = NULL;
 	int level, max_level = ilk_wm_max_level(dev);
 	/* LP0 watermark maximums depend on this pipe alone */
 	struct intel_wm_config config = {
@@ -2302,11 +2289,24 @@ static bool intel_compute_pipe_wm(struct intel_crtc_state *cstate,
 	};
 	struct ilk_wm_maximums max;
 
+	cstate = intel_atomic_get_crtc_state(state, intel_crtc);
+	if (IS_ERR(cstate))
+		return PTR_ERR(cstate);
+
+	pipe_wm = &cstate->wm.optimal.ilk;
+
 	for_each_intel_plane_on_crtc(dev, intel_crtc, intel_plane) {
-		if (intel_plane->base.type == DRM_PLANE_TYPE_OVERLAY) {
-			sprstate = to_intel_plane_state(intel_plane->base.state);
-			break;
-		}
+		ps = drm_atomic_get_plane_state(state,
+						&intel_plane->base);
+		if (IS_ERR(ps))
+			return PTR_ERR(ps);
+
+		if (intel_plane->base.type == DRM_PLANE_TYPE_PRIMARY)
+			pristate = to_intel_plane_state(ps);
+		else if (intel_plane->base.type == DRM_PLANE_TYPE_OVERLAY)
+			sprstate = to_intel_plane_state(ps);
+		else if (intel_plane->base.type == DRM_PLANE_TYPE_CURSOR)
+			curstate = to_intel_plane_state(ps);
 	}
 
 	config.sprites_enabled = sprstate->visible;
@@ -2315,7 +2315,7 @@ static bool intel_compute_pipe_wm(struct intel_crtc_state *cstate,
 		drm_rect_height(&sprstate->dst) != drm_rect_height(&sprstate->src) >> 16);
 
 	pipe_wm->pipe_enabled = cstate->base.active;
-	pipe_wm->sprites_enabled = sprstate->visible;
+	pipe_wm->sprites_enabled = config.sprites_enabled;
 	pipe_wm->sprites_scaled = config.sprites_scaled;
 
 	/* ILK/SNB: LP2+ watermarks only w/o sprites */
@@ -2326,24 +2326,27 @@ static bool intel_compute_pipe_wm(struct intel_crtc_state *cstate,
 	if (config.sprites_scaled)
 		max_level = 0;
 
-	ilk_compute_wm_level(dev_priv, intel_crtc, 0, cstate, &pipe_wm->wm[0]);
+	ilk_compute_wm_level(dev_priv, intel_crtc, 0, cstate,
+			     pristate, sprstate, curstate, &pipe_wm->wm[0]);
 
 	if (IS_HASWELL(dev) || IS_BROADWELL(dev))
-		pipe_wm->linetime = hsw_compute_linetime_wm(dev, crtc);
+		pipe_wm->linetime = hsw_compute_linetime_wm(dev,
+							    &intel_crtc->base);
 
 	/* LP0 watermarks always use 1/2 DDB partitioning */
 	ilk_compute_wm_maximums(dev, 0, &config, INTEL_DDB_PART_1_2, &max);
 
 	/* At least LP0 must be valid */
 	if (!ilk_validate_wm_level(0, &max, &pipe_wm->wm[0]))
-		return false;
+		return -EINVAL;
 
 	ilk_compute_wm_reg_maximums(dev, 1, &max);
 
 	for (level = 1; level <= max_level; level++) {
 		struct intel_wm_level wm = {};
 
-		ilk_compute_wm_level(dev_priv, intel_crtc, level, cstate, &wm);
+		ilk_compute_wm_level(dev_priv, intel_crtc, level, cstate,
+				     pristate, sprstate, curstate, &wm);
 
 		/*
 		 * Disable any watermark level that exceeds the
@@ -2356,7 +2359,7 @@ static bool intel_compute_pipe_wm(struct intel_crtc_state *cstate,
 		pipe_wm->wm[level] = wm;
 	}
 
-	return true;
+	return 0;
 }
 
 /*
@@ -3674,12 +3677,6 @@ static void ilk_update_wm(struct drm_crtc *crtc)
 		intel_wait_for_vblank(crtc->dev, intel_crtc->pipe);
 	}
 
-	intel_compute_pipe_wm(cstate, &cstate->wm.optimal.ilk);
-
-	if (!memcmp(&intel_crtc->wm.active.ilk,
-		    &cstate->wm.optimal.ilk,
-		    sizeof(cstate->wm.optimal.ilk)));
-
 	intel_crtc->wm.active.ilk = cstate->wm.optimal.ilk;
 
 	ilk_program_watermarks(dev_priv);
@@ -6988,6 +6985,7 @@ void intel_init_pm(struct drm_device *dev)
 		    (!IS_GEN5(dev) && dev_priv->wm.pri_latency[0] &&
 		     dev_priv->wm.spr_latency[0] && dev_priv->wm.cur_latency[0])) {
 			dev_priv->display.update_wm = ilk_update_wm;
+			dev_priv->display.compute_pipe_wm = ilk_compute_pipe_wm;
 		} else {
 			DRM_DEBUG_KMS("Failed to read display plane latency. "
 				      "Disable CxSR\n");