[Intel-gfx] [PATCH] drm/i915: Add the ddi get cdclk code for BXT (v2)

[Matt Roper]

From: Bob Paauwe <bob.j.paauwe at intel.com>

The registers and process differ from other platforms.

v2(Matt): Return 19.2 MHz when DE PLL is disabled (Ville)

Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Imre Deak <imre.deak at intel.com>
Signed-off-by: Bob Paauwe <bob.j.paauwe at intel.com>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3ee7dbc..294c4e4 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6689,6 +6689,34 @@ static int skylake_get_display_clock_speed(struct drm_device *dev)
 	return 24000;
 }
 
+static int broxton_get_display_clock_speed(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	uint32_t cdctl = I915_READ(CDCLK_CTL);
+	uint32_t pll_freq = I915_READ(BXT_DE_PLL_CTL) & BXT_DE_PLL_RATIO_MASK;
+	uint32_t pll_enab = I915_READ(BXT_DE_PLL_ENABLE);
+
+	if (!(pll_enab & BXT_DE_PLL_PLL_ENABLE))
+		return 19200;
+
+	switch (cdctl & BXT_CDCLK_CD2X_DIV_SEL_MASK) {
+	case BXT_CDCLK_CD2X_DIV_SEL_1:
+		if (pll_freq == BXT_DE_PLL_RATIO(60)) /* PLL freq = 1152MHz */
+			return 576000;
+		else /* PLL freq = 1248MHz */
+			return 624000;
+	case BXT_CDCLK_CD2X_DIV_SEL_1_5:
+		return 384000;
+	case BXT_CDCLK_CD2X_DIV_SEL_2:
+		return 288000;
+	case BXT_CDCLK_CD2X_DIV_SEL_4:
+		return 144000;
+	}
+
+	/* error case, assume higer PLL freq. */
+	return 624000;
+}
+
 static int broadwell_get_display_clock_speed(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -14715,6 +14743,9 @@ static void intel_init_display(struct drm_device *dev)
 	if (IS_SKYLAKE(dev))
 		dev_priv->display.get_display_clock_speed =
 			skylake_get_display_clock_speed;
+	else if (IS_BROXTON(dev))
+		dev_priv->display.get_display_clock_speed =
+			broxton_get_display_clock_speed;
 	else if (IS_BROADWELL(dev))
 		dev_priv->display.get_display_clock_speed =
 			broadwell_get_display_clock_speed;
-- 
1.8.5.1