From 52bf130b7e842a7eef61ef09e4193c5af6bd9c74 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Fri, 19 Nov 2021 15:13:48 +0200
Subject: drm/i915: Allow cdclk squasher to be reconfigured live
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: d4a23930490df39fd076a82649ddba6b3a6c8216
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Supposedly we should be able to change the cdclk squasher waveform
even when many pipes are active. Make it so.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211119131348.725220-6-mika.kahola@intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/display/intel_cdclk.c | 40 ++++++++++++++++++++--
 1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
index 728263cf40e3..a5569f21811c 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -1951,6 +1951,25 @@ static bool intel_cdclk_can_crawl(struct drm_i915_private *dev_priv,
 		a->ref == b->ref;
 }
 
+static bool intel_cdclk_can_squash(struct drm_i915_private *dev_priv,
+				   const struct intel_cdclk_config *a,
+				   const struct intel_cdclk_config *b)
+{
+	/*
+	 * FIXME should store a bit more state in intel_cdclk_config
+	 * to differentiate squasher vs. cd2x divider properly. For
+	 * the moment all platforms with squasher use a fixed cd2x
+	 * divider.
+	 */
+	if (!has_cdclk_squasher(dev_priv))
+		return false;
+
+	return a->cdclk != b->cdclk &&
+		a->vco != 0 &&
+		a->vco == b->vco &&
+		a->ref == b->ref;
+}
+
 /**
  * intel_cdclk_needs_modeset - Determine if changong between the CDCLK
  *                             configurations requires a modeset on all pipes
@@ -1988,7 +2007,17 @@ static bool intel_cdclk_can_cd2x_update(struct drm_i915_private *dev_priv,
 	if (DISPLAY_VER(dev_priv) < 10 && !IS_BROXTON(dev_priv))
 		return false;
 
+	/*
+	 * FIXME should store a bit more state in intel_cdclk_config
+	 * to differentiate squasher vs. cd2x divider properly. For
+	 * the moment all platforms with squasher use a fixed cd2x
+	 * divider.
+	 */
+	if (has_cdclk_squasher(dev_priv))
+		return false;
+
 	return a->cdclk != b->cdclk &&
+		a->vco != 0 &&
 		a->vco == b->vco &&
 		a->ref == b->ref;
 }
@@ -2672,9 +2701,14 @@ int intel_modeset_calc_cdclk(struct intel_atomic_state *state)
 			pipe = INVALID_PIPE;
 	}
 
-	if (intel_cdclk_can_crawl(dev_priv,
-				  &old_cdclk_state->actual,
-				  &new_cdclk_state->actual)) {
+	if (intel_cdclk_can_squash(dev_priv,
+				   &old_cdclk_state->actual,
+				   &new_cdclk_state->actual)) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "Can change cdclk via squasher\n");
+	} else if (intel_cdclk_can_crawl(dev_priv,
+					 &old_cdclk_state->actual,
+					 &new_cdclk_state->actual)) {
 		drm_dbg_kms(&dev_priv->drm,
 			    "Can change cdclk via crawl\n");
 	} else if (pipe != INVALID_PIPE) {
-- 
2.38.1