drm/i915/glk: Reuse broxton's cdclk code for GLK

Geminilake has the same register layout, reference clock and programming
sequence as broxton. The difference is that it doesn't support the 1.5
divider and has different ratios, but a lot of code can be shared
between the two platforms.

v2: Rebase (s/broxton/bxt).

v3: Fix vco calculation in glk_de_pll_vco().
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1480667037-11215-7-git-send-email-ander.conselvan.de.oliveira@intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -124,6 +124,7 @@ static void ironlake_pfit_enable(struct intel_crtc *crtc);
 static void intel_modeset_setup_hw_state(struct drm_device *dev);
 static void intel_pre_disable_primary_noatomic(struct drm_crtc *crtc);
 static int ilk_max_pixel_rate(struct drm_atomic_state *state);
+static int glk_calc_cdclk(int max_pixclk);
 static int bxt_calc_cdclk(int max_pixclk);
 
 struct intel_limit {
@@ -5841,6 +5842,8 @@ static void intel_update_max_cdclk(struct drm_i915_private *dev_priv)
 			max_cdclk = 308571;
 
 		dev_priv->max_cdclk_freq = skl_calc_cdclk(max_cdclk, vco);
+	} else if (IS_GEMINILAKE(dev_priv)) {
+		dev_priv->max_cdclk_freq = 316800;
 	} else if (IS_BROXTON(dev_priv)) {
 		dev_priv->max_cdclk_freq = 624000;
 	} else if (IS_BROADWELL(dev_priv))  {
@@ -5928,6 +5931,26 @@ static int bxt_de_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
 	return dev_priv->cdclk_pll.ref * ratio;
 }
 
+static int glk_de_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
+{
+	int ratio;
+
+	if (cdclk == dev_priv->cdclk_pll.ref)
+		return 0;
+
+	switch (cdclk) {
+	default:
+		MISSING_CASE(cdclk);
+	case  79200:
+	case 158400:
+	case 316800:
+		ratio = 33;
+		break;
+	}
+
+	return dev_priv->cdclk_pll.ref * ratio;
+}
+
 static void bxt_de_pll_disable(struct drm_i915_private *dev_priv)
 {
 	I915_WRITE(BXT_DE_PLL_ENABLE, 0);
@@ -5969,6 +5992,9 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv, int cdclk)
 	u32 val, divider;
 	int vco, ret;
 
+	if (IS_GEMINILAKE(dev_priv))
+		vco = glk_de_pll_vco(dev_priv, cdclk);
+	else
 		vco = bxt_de_pll_vco(dev_priv, cdclk);
 
 	DRM_DEBUG_DRIVER("Changing CDCLK to %d kHz (VCO %d kHz)\n", cdclk, vco);
@@ -5982,6 +6008,7 @@ static void bxt_set_cdclk(struct drm_i915_private *dev_priv, int cdclk)
 		divider = BXT_CDCLK_CD2X_DIV_SEL_2;
 		break;
 	case 3:
+		WARN(IS_GEMINILAKE(dev_priv), "Unsupported divider\n");
 		divider = BXT_CDCLK_CD2X_DIV_SEL_1_5;
 		break;
 	case 2:
@@ -6091,6 +6118,8 @@ static void bxt_sanitize_cdclk(struct drm_i915_private *dev_priv)
 
 void bxt_init_cdclk(struct drm_i915_private *dev_priv)
 {
+	int cdclk;
+
 	bxt_sanitize_cdclk(dev_priv);
 
 	if (dev_priv->cdclk_freq != 0 && dev_priv->cdclk_pll.vco != 0)
@@ -6101,7 +6130,12 @@ void bxt_init_cdclk(struct drm_i915_private *dev_priv)
 	 * - The initial CDCLK needs to be read from VBT.
 	 *   Need to make this change after VBT has changes for BXT.
 	 */
-	bxt_set_cdclk(dev_priv, bxt_calc_cdclk(0));
+	if (IS_GEMINILAKE(dev_priv))
+		cdclk = glk_calc_cdclk(0);
+	else
+		cdclk = bxt_calc_cdclk(0);
+
+	bxt_set_cdclk(dev_priv, cdclk);
 }
 
 void bxt_uninit_cdclk(struct drm_i915_private *dev_priv)
@@ -6527,6 +6561,16 @@ static int valleyview_calc_cdclk(struct drm_i915_private *dev_priv,
 		return 200000;
 }
 
+static int glk_calc_cdclk(int max_pixclk)
+{
+	if (max_pixclk > 158400)
+		return 316800;
+	else if (max_pixclk > 79200)
+		return 158400;
+	else
+		return 79200;
+}
+
 static int bxt_calc_cdclk(int max_pixclk)
 {
 	if (max_pixclk > 576000)
@@ -6589,15 +6633,27 @@ static int valleyview_modeset_calc_cdclk(struct drm_atomic_state *state)
 
 static int bxt_modeset_calc_cdclk(struct drm_atomic_state *state)
 {
+	struct drm_i915_private *dev_priv = to_i915(state->dev);
 	int max_pixclk = ilk_max_pixel_rate(state);
 	struct intel_atomic_state *intel_state =
 		to_intel_atomic_state(state);
+	int cdclk;
 
-	intel_state->cdclk = intel_state->dev_cdclk =
-		bxt_calc_cdclk(max_pixclk);
+	if (IS_GEMINILAKE(dev_priv))
+		cdclk = glk_calc_cdclk(max_pixclk);
+	else
+		cdclk = bxt_calc_cdclk(max_pixclk);
 
-	if (!intel_state->active_crtcs)
-		intel_state->dev_cdclk = bxt_calc_cdclk(0);
+	intel_state->cdclk = intel_state->dev_cdclk = cdclk;
+
+	if (!intel_state->active_crtcs) {
+		if (IS_GEMINILAKE(dev_priv))
+			cdclk = glk_calc_cdclk(0);
+		else
+			cdclk = bxt_calc_cdclk(0);
+
+		intel_state->dev_cdclk = cdclk;
+	}
 
 	return 0;
 }
@@ -7299,6 +7355,7 @@ static int broxton_get_display_clock_speed(struct drm_i915_private *dev_priv)
 		div = 2;
 		break;
 	case BXT_CDCLK_CD2X_DIV_SEL_1_5:
+		WARN(IS_GEMINILAKE(dev_priv), "Unsupported divider\n");
 		div = 3;
 		break;
 	case BXT_CDCLK_CD2X_DIV_SEL_2:
@@ -16031,7 +16088,7 @@ void intel_init_display_hooks(struct drm_i915_private *dev_priv)
 	if (IS_SKYLAKE(dev_priv) || IS_KABYLAKE(dev_priv))
 		dev_priv->display.get_display_clock_speed =
 			skylake_get_display_clock_speed;
-	else if (IS_BROXTON(dev_priv))
+	else if (IS_GEN9_LP(dev_priv))
 		dev_priv->display.get_display_clock_speed =
 			broxton_get_display_clock_speed;
 	else if (IS_BROADWELL(dev_priv))
@@ -16104,7 +16161,7 @@ void intel_init_display_hooks(struct drm_i915_private *dev_priv)
 			valleyview_modeset_commit_cdclk;
 		dev_priv->display.modeset_calc_cdclk =
 			valleyview_modeset_calc_cdclk;
-	} else if (IS_BROXTON(dev_priv)) {
+	} else if (IS_GEN9_LP(dev_priv)) {
 		dev_priv->display.modeset_commit_cdclk =
 			bxt_modeset_commit_cdclk;
 		dev_priv->display.modeset_calc_cdclk =