1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 292d69e52cc5..cc68e4179a5a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6624,6 +6624,34 @@ 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_ratio = I915_READ(BXT_DE_PLL_CTL) & BXT_DE_PLL_RATIO_MASK;
+        uint32_t pll_enab = I915_READ(BXT_DE_PLL_ENABLE);
+        int cdclk;
+
+        if (!(pll_enab & BXT_DE_PLL_PLL_ENABLE))
+                return 19200;
+
+        cdclk = 19200 * pll_ratio / 2;
+
+        switch (cdctl & BXT_CDCLK_CD2X_DIV_SEL_MASK) {
+        case BXT_CDCLK_CD2X_DIV_SEL_1:
+                return cdclk;  /* 576MHz or 624MHz */
+        case BXT_CDCLK_CD2X_DIV_SEL_1_5:
+                return cdclk * 2 / 3; /* 384MHz */
+        case BXT_CDCLK_CD2X_DIV_SEL_2:
+                return cdclk / 2; /* 288MHz */
+        case BXT_CDCLK_CD2X_DIV_SEL_4:
+                return cdclk / 4; /* 144MHz */
+        }
+
+        /* error case, do as if DE PLL isn't enabled */
+        return 19200;
+}
+
 static int broadwell_get_display_clock_speed(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
@@ -14615,6 +14643,9 @@ 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;