[v4,7/8] drm/i915: Enhance cdclk sanitization
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Message ID 20190910154252.30503-8-matthew.d.roper@intel.com
State New
Headers show
Series
  • cdclk consolidation and rework for BXT-TGL
Related show

Commit Message

Matt Roper Sept. 10, 2019, 3:42 p.m. UTC
When reading out the BIOS-programmed cdclk state, let's make sure that
the cdclk value is on the valid list for the platform, ensure that the
VCO matches the cdclk, and ensure that the CD2X divider was set
properly.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_cdclk.c | 34 ++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

Patch
diff mbox series

diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
index cb2fc68c9335..686c1e6100f0 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -1598,6 +1598,7 @@  static void bxt_set_cdclk(struct drm_i915_private *dev_priv,
 static void bxt_sanitize_cdclk(struct drm_i915_private *dev_priv)
 {
 	u32 cdctl, expected;
+	int cdclk, vco;
 
 	intel_update_cdclk(dev_priv);
 	intel_dump_cdclk_state(&dev_priv->cdclk.hw, "Current CDCLK");
@@ -1620,8 +1621,37 @@  static void bxt_sanitize_cdclk(struct drm_i915_private *dev_priv)
 	 */
 	cdctl &= ~BXT_CDCLK_CD2X_PIPE_NONE;
 
-	expected = (cdctl & BXT_CDCLK_CD2X_DIV_SEL_MASK) |
-		skl_cdclk_decimal(dev_priv->cdclk.hw.cdclk);
+	/* Make sure this is a legal cdclk value for the platform */
+	cdclk = bxt_calc_cdclk(dev_priv, dev_priv->cdclk.hw.cdclk);
+	if (cdclk != dev_priv->cdclk.hw.cdclk)
+		goto sanitize;
+
+	/* Make sure the VCO is correct for the cdclk */
+	vco = bxt_calc_cdclk_pll_vco(dev_priv, cdclk);
+	if (vco != dev_priv->cdclk.hw.vco)
+		goto sanitize;
+
+	expected = skl_cdclk_decimal(cdclk);
+
+	/* Figure out what CD2X divider we should be using for this cdclk */
+	switch (DIV_ROUND_CLOSEST(dev_priv->cdclk.hw.vco,
+				  dev_priv->cdclk.hw.cdclk)) {
+	case 2:
+		expected |= BXT_CDCLK_CD2X_DIV_SEL_1;
+		break;
+	case 3:
+		expected |= BXT_CDCLK_CD2X_DIV_SEL_1_5;
+		break;
+	case 4:
+		expected |= BXT_CDCLK_CD2X_DIV_SEL_2;
+		break;
+	case 8:
+		expected |= BXT_CDCLK_CD2X_DIV_SEL_4;
+		break;
+	default:
+		goto sanitize;
+	}
+
 	/*
 	 * Disable SSA Precharge when CD clock frequency < 500 MHz,
 	 * enable otherwise.