[Intel-gfx] [PATCH 1/2] drm/i915/gen9: Assume CDCLK PLL is off if it's not locked

[Imre Deak]

If the CDCLK PLL isn't locked we can just assume that it's off resulting
in fully re-initializing both CDCLK PLL and CDCLK dividers. This way the
CDCLK PLL sanitization added in the following patch can be done on BXT
the same way as it's done on SKL.

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c1e666b..b8e5995 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5461,14 +5461,14 @@ skl_dpll0_update(struct drm_i915_private *dev_priv)
 	u32 val;
 
 	dev_priv->cdclk_pll.ref = 24000;
+	dev_priv->cdclk_pll.vco = 0;
 
 	val = I915_READ(LCPLL1_CTL);
-	if ((val & LCPLL_PLL_ENABLE) == 0) {
-		dev_priv->cdclk_pll.vco = 0;
+	if ((val & LCPLL_PLL_ENABLE) == 0)
 		return;
-	}
 
-	WARN_ON((val & LCPLL_PLL_LOCK) == 0);
+	if (WARN_ON((val & LCPLL_PLL_LOCK) == 0))
+		return;
 
 	val = I915_READ(DPLL_CTRL1);
 
@@ -5690,9 +5690,10 @@ static void skl_sanitize_cdclk(struct drm_i915_private *dev_priv)
 	if ((I915_READ(SWF_ILK(0x18)) & 0x00FFFFFF) == 0)
 		goto sanitize;
 
+	intel_update_cdclk(dev_priv->dev);
 	/* Is PLL enabled and locked ? */
-	if ((I915_READ(LCPLL1_CTL) & (LCPLL_PLL_ENABLE | LCPLL_PLL_LOCK)) !=
-	    (LCPLL_PLL_ENABLE | LCPLL_PLL_LOCK))
+	if (!dev_priv->cdclk_pll.vco ||
+	    dev_priv->cdclk_freq == dev_priv->cdclk_pll.ref)
 		goto sanitize;
 
 	if ((I915_READ(DPLL_CTRL1) & (DPLL_CTRL1_HDMI_MODE(SKL_DPLL0) |
@@ -5701,8 +5702,6 @@ static void skl_sanitize_cdclk(struct drm_i915_private *dev_priv)
 	    DPLL_CTRL1_OVERRIDE(SKL_DPLL0))
 		goto sanitize;
 
-	intel_update_cdclk(dev_priv->dev);
-
 	/* DPLL okay; verify the cdclock
 	 *
 	 * Noticed in some instances that the freq selection is correct but
@@ -6608,14 +6607,14 @@ static void bxt_de_pll_update(struct drm_i915_private *dev_priv)
 	u32 val;
 
 	dev_priv->cdclk_pll.ref = 19200;
+	dev_priv->cdclk_pll.vco = 0;
 
 	val = I915_READ(BXT_DE_PLL_ENABLE);
-	if ((val & BXT_DE_PLL_PLL_ENABLE) == 0) {
-		dev_priv->cdclk_pll.vco = 0;
+	if ((val & BXT_DE_PLL_PLL_ENABLE) == 0)
 		return;
-	}
 
-	WARN_ON((val & BXT_DE_PLL_LOCK) == 0);
+	if (WARN_ON((val & BXT_DE_PLL_LOCK) == 0))
+		return;
 
 	val = I915_READ(BXT_DE_PLL_CTL);
 	dev_priv->cdclk_pll.vco = (val & BXT_DE_PLL_RATIO_MASK) *
-- 
2.5.0