The registers and process differ from other platforms. If the hardware
was programmed incorrectly, this will return invalid cdclk values, which
should then cause reprogramming of the hardware.
v2(Matt): Return 19.2 MHz when DE PLL is disabled (Ville)
v3: Make less assumptions about the hardware state (Ville)
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Cc: Imre Deak <imre.d...@intel.com>
Cc: Matt Roper <matthew.d.ro...@intel.com>
Signed-off-by: Bob Paauwe <bob.j.paa...@intel.com>
Signed-off-by: Matt Roper <matthew.d.ro...@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 c38c297..201826e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6687,6 +6687,34 @@ 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;
@@ -14649,6 +14677,9 @@ 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;
--
2.1.0
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