drm/i915: Consolidate bxt/cnl/icl cdclk readout

Aside from a few minor register changes and some different clock values,
cdclk design hasn't changed much since gen9lp.  Let's consolidate the
handlers for bxt, cnl, and icl to keep the codeflow consistent.

Also, while we're at it, s/bxt_de_pll_update/bxt_de_pll_readout/ since
"update" makes me think we should be writing to hardware rather than
reading from it.

v2:
 - Fix icl_calc_voltage_level() limits.  (Ville)
 - Use CNL_CDCLK_PLL_RATIO_MASK rather than BXT_DE_PLL_RATIO_MASK on
   gen10+ to avoid confusion.  (Ville)

v3:
 - Also fix ehl_calc_voltage_level() limits.  (Ville)

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190910160520.6587-1-matthew.d.roper@intel.com

drivers/gpu/drm/i915/display/intel_cdclk.c

@@ -1190,6 +1190,36 @@ static u8 bxt_calc_voltage_level(int cdclk)
 	return DIV_ROUND_UP(cdclk, 25000);
 }
 
+static u8 cnl_calc_voltage_level(int cdclk)
+{
+	if (cdclk > 336000)
+		return 2;
+	else if (cdclk > 168000)
+		return 1;
+	else
+		return 0;
+}
+
+static u8 icl_calc_voltage_level(int cdclk)
+{
+	if (cdclk > 556800)
+		return 2;
+	else if (cdclk > 312000)
+		return 1;
+	else
+		return 0;
+}
+
+static u8 ehl_calc_voltage_level(int cdclk)
+{
+	if (cdclk > 312000)
+		return 2;
+	else if (cdclk > 180000)
+		return 1;
+	else
+		return 0;
+}
+
 static int bxt_de_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
 {
 	int ratio;
@@ -1236,23 +1266,69 @@ static int glk_de_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
 	return dev_priv->cdclk.hw.ref * ratio;
 }
 
-static void bxt_de_pll_update(struct drm_i915_private *dev_priv,
-			      struct intel_cdclk_state *cdclk_state)
+static void cnl_readout_refclk(struct drm_i915_private *dev_priv,
+			       struct intel_cdclk_state *cdclk_state)
 {
-	u32 val;
+	if (I915_READ(SKL_DSSM) & CNL_DSSM_CDCLK_PLL_REFCLK_24MHz)
+		cdclk_state->ref = 24000;
+	else
+		cdclk_state->ref = 19200;
+}
 
-	cdclk_state->ref = 19200;
-	cdclk_state->vco = 0;
+static void icl_readout_refclk(struct drm_i915_private *dev_priv,
+			       struct intel_cdclk_state *cdclk_state)
+{
+	u32 dssm = I915_READ(SKL_DSSM) & ICL_DSSM_CDCLK_PLL_REFCLK_MASK;
+
+	switch (dssm) {
+	default:
+		MISSING_CASE(dssm);
+		/* fall through */
+	case ICL_DSSM_CDCLK_PLL_REFCLK_24MHz:
+		cdclk_state->ref = 24000;
+		break;
+	case ICL_DSSM_CDCLK_PLL_REFCLK_19_2MHz:
+		cdclk_state->ref = 19200;
+		break;
+	case ICL_DSSM_CDCLK_PLL_REFCLK_38_4MHz:
+		cdclk_state->ref = 38400;
+		break;
+	}
+}
+
+static void bxt_de_pll_readout(struct drm_i915_private *dev_priv,
+			       struct intel_cdclk_state *cdclk_state)
+{
+	u32 val, ratio;
+
+	if (INTEL_GEN(dev_priv) >= 11)
+		icl_readout_refclk(dev_priv, cdclk_state);
+	else if (IS_CANNONLAKE(dev_priv))
+		cnl_readout_refclk(dev_priv, cdclk_state);
+	else
+		cdclk_state->ref = 19200;
 
 	val = I915_READ(BXT_DE_PLL_ENABLE);
-	if ((val & BXT_DE_PLL_PLL_ENABLE) == 0)
+	if ((val & BXT_DE_PLL_PLL_ENABLE) == 0 ||
+	    (val & BXT_DE_PLL_LOCK) == 0) {
+		/*
+		 * CDCLK PLL is disabled, the VCO/ratio doesn't matter, but
+		 * setting it to zero is a way to signal that.
+		 */
+		cdclk_state->vco = 0;
 		return;
+	}
 
-	if (WARN_ON((val & BXT_DE_PLL_LOCK) == 0))
-		return;
+	/*
+	 * CNL+ have the ratio directly in the PLL enable register, gen9lp had
+	 * it in a separate PLL control register.
+	 */
+	if (INTEL_GEN(dev_priv) >= 10)
+		ratio = val & CNL_CDCLK_PLL_RATIO_MASK;
+	else
+		ratio = I915_READ(BXT_DE_PLL_CTL) & BXT_DE_PLL_RATIO_MASK;
 
-	val = I915_READ(BXT_DE_PLL_CTL);
-	cdclk_state->vco = (val & BXT_DE_PLL_RATIO_MASK) * cdclk_state->ref;
+	cdclk_state->vco = ratio * cdclk_state->ref;
 }
 
 static void bxt_get_cdclk(struct drm_i915_private *dev_priv,
@@ -1261,12 +1337,18 @@ static void bxt_get_cdclk(struct drm_i915_private *dev_priv,
 	u32 divider;
 	int div;
 
-	bxt_de_pll_update(dev_priv, cdclk_state);
-
-	cdclk_state->cdclk = cdclk_state->bypass = cdclk_state->ref;
+	if (INTEL_GEN(dev_priv) >= 12)
+		cdclk_state->bypass = cdclk_state->ref / 2;
+	else if (INTEL_GEN(dev_priv) >= 11)
+		cdclk_state->bypass = 50000;
+	else
+		cdclk_state->bypass = cdclk_state->ref;
 
-	if (cdclk_state->vco == 0)
+	bxt_de_pll_readout(dev_priv, cdclk_state);
+	if (cdclk_state->vco == 0) {
+		cdclk_state->cdclk = cdclk_state->bypass;
 		goto out;
+	}
 
 	divider = I915_READ(CDCLK_CTL) & BXT_CDCLK_CD2X_DIV_SEL_MASK;
 
@@ -1275,13 +1357,15 @@ static void bxt_get_cdclk(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");
+		WARN(IS_GEMINILAKE(dev_priv) || INTEL_GEN(dev_priv) >= 10,
+		     "Unsupported divider\n");
 		div = 3;
 		break;
 	case BXT_CDCLK_CD2X_DIV_SEL_2:
 		div = 4;
 		break;
 	case BXT_CDCLK_CD2X_DIV_SEL_4:
+		WARN(INTEL_GEN(dev_priv) >= 10, "Unsupported divider\n");
 		div = 8;
 		break;
 	default:
@@ -1296,8 +1380,18 @@ static void bxt_get_cdclk(struct drm_i915_private *dev_priv,
 	 * Can't read this out :( Let's assume it's
 	 * at least what the CDCLK frequency requires.
 	 */
-	cdclk_state->voltage_level =
-		bxt_calc_voltage_level(cdclk_state->cdclk);
+	if (IS_ELKHARTLAKE(dev_priv))
+		cdclk_state->voltage_level =
+			ehl_calc_voltage_level(cdclk_state->cdclk);
+	else if (INTEL_GEN(dev_priv) >= 11)
+		cdclk_state->voltage_level =
+			icl_calc_voltage_level(cdclk_state->cdclk);
+	else if (INTEL_GEN(dev_priv) >= 10)
+		cdclk_state->voltage_level =
+			cnl_calc_voltage_level(cdclk_state->cdclk);
+	else
+		cdclk_state->voltage_level =
+			bxt_calc_voltage_level(cdclk_state->cdclk);
 }
 
 static void bxt_de_pll_disable(struct drm_i915_private *dev_priv)
@@ -1515,76 +1609,6 @@ static int cnl_calc_cdclk(int min_cdclk)
 		return 168000;
 }
 
-static u8 cnl_calc_voltage_level(int cdclk)
-{
-	if (cdclk > 336000)
-		return 2;
-	else if (cdclk > 168000)
-		return 1;
-	else
-		return 0;
-}
-
-static void cnl_cdclk_pll_update(struct drm_i915_private *dev_priv,
-				 struct intel_cdclk_state *cdclk_state)
-{
-	u32 val;
-
-	if (I915_READ(SKL_DSSM) & CNL_DSSM_CDCLK_PLL_REFCLK_24MHz)
-		cdclk_state->ref = 24000;
-	else
-		cdclk_state->ref = 19200;
-
-	cdclk_state->vco = 0;
-
-	val = I915_READ(BXT_DE_PLL_ENABLE);
-	if ((val & BXT_DE_PLL_PLL_ENABLE) == 0)
-		return;
-
-	if (WARN_ON((val & BXT_DE_PLL_LOCK) == 0))
-		return;
-
-	cdclk_state->vco = (val & CNL_CDCLK_PLL_RATIO_MASK) * cdclk_state->ref;
-}
-
-static void cnl_get_cdclk(struct drm_i915_private *dev_priv,
-			 struct intel_cdclk_state *cdclk_state)
-{
-	u32 divider;
-	int div;
-
-	cnl_cdclk_pll_update(dev_priv, cdclk_state);
-
-	cdclk_state->cdclk = cdclk_state->bypass = cdclk_state->ref;
-
-	if (cdclk_state->vco == 0)
-		goto out;
-
-	divider = I915_READ(CDCLK_CTL) & BXT_CDCLK_CD2X_DIV_SEL_MASK;
-
-	switch (divider) {
-	case BXT_CDCLK_CD2X_DIV_SEL_1:
-		div = 2;
-		break;
-	case BXT_CDCLK_CD2X_DIV_SEL_2:
-		div = 4;
-		break;
-	default:
-		MISSING_CASE(divider);
-		return;
-	}
-
-	cdclk_state->cdclk = DIV_ROUND_CLOSEST(cdclk_state->vco, div);
-
- out:
-	/*
-	 * Can't read this out :( Let's assume it's
-	 * at least what the CDCLK frequency requires.
-	 */
-	cdclk_state->voltage_level =
-		cnl_calc_voltage_level(cdclk_state->cdclk);
-}
-
 static void cnl_cdclk_pll_disable(struct drm_i915_private *dev_priv)
 {
 	u32 val;
@@ -1830,91 +1854,6 @@ static int icl_calc_cdclk_pll_vco(struct drm_i915_private *dev_priv, int cdclk)
 	return dev_priv->cdclk.hw.ref * ratio;
 }
 
-static u8 icl_calc_voltage_level(struct drm_i915_private *dev_priv, int cdclk)
-{
-	if (IS_ELKHARTLAKE(dev_priv)) {
-		if (cdclk > 312000)
-			return 2;
-		else if (cdclk > 180000)
-			return 1;
-		else
-			return 0;
-	} else {
-		if (cdclk > 556800)
-			return 2;
-		else if (cdclk > 312000)
-			return 1;
-		else
-			return 0;
-	}
-}
-
-static void icl_get_cdclk(struct drm_i915_private *dev_priv,
-			  struct intel_cdclk_state *cdclk_state)
-{
-	u32 val;
-	int div;
-
-	val = I915_READ(SKL_DSSM);
-	switch (val & ICL_DSSM_CDCLK_PLL_REFCLK_MASK) {
-	default:
-		MISSING_CASE(val);
-		/* fall through */
-	case ICL_DSSM_CDCLK_PLL_REFCLK_24MHz:
-		cdclk_state->ref = 24000;
-		break;
-	case ICL_DSSM_CDCLK_PLL_REFCLK_19_2MHz:
-		cdclk_state->ref = 19200;
-		break;
-	case ICL_DSSM_CDCLK_PLL_REFCLK_38_4MHz:
-		cdclk_state->ref = 38400;
-		break;
-	}
-
-	if (INTEL_GEN(dev_priv) >= 12)
-		cdclk_state->bypass = cdclk_state->ref / 2;
-	else
-		cdclk_state->bypass = 50000;
-
-	val = I915_READ(BXT_DE_PLL_ENABLE);
-	if ((val & BXT_DE_PLL_PLL_ENABLE) == 0 ||
-	    (val & BXT_DE_PLL_LOCK) == 0) {
-		/*
-		 * CDCLK PLL is disabled, the VCO/ratio doesn't matter, but
-		 * setting it to zero is a way to signal that.
-		 */
-		cdclk_state->vco = 0;
-		cdclk_state->cdclk = cdclk_state->bypass;
-		goto out;
-	}
-
-	cdclk_state->vco = (val & BXT_DE_PLL_RATIO_MASK) * cdclk_state->ref;
-
-	val = I915_READ(CDCLK_CTL) & BXT_CDCLK_CD2X_DIV_SEL_MASK;
-	switch (val) {
-	case BXT_CDCLK_CD2X_DIV_SEL_1:
-		div = 2;
-		break;
-	case BXT_CDCLK_CD2X_DIV_SEL_2:
-		div = 4;
-		break;
-	default:
-		MISSING_CASE(val);
-		div = 2;
-		break;
-	}
-
-	cdclk_state->cdclk = DIV_ROUND_CLOSEST(cdclk_state->vco, div);
-
-out:
-	/*
-	 * Can't read this out :( Let's assume it's
-	 * at least what the CDCLK frequency requires.
-	 */
-	cdclk_state->voltage_level =
-		icl_calc_voltage_level(dev_priv, cdclk_state->cdclk);
-}
-
 static void icl_init_cdclk(struct drm_i915_private *dev_priv)
 {
 	struct intel_cdclk_state sanitized_state;
@@ -1946,9 +1885,12 @@ static void icl_init_cdclk(struct drm_i915_private *dev_priv)
 	sanitized_state.cdclk = icl_calc_cdclk(0, sanitized_state.ref);
 	sanitized_state.vco = icl_calc_cdclk_pll_vco(dev_priv,
 						     sanitized_state.cdclk);
-	sanitized_state.voltage_level =
-				icl_calc_voltage_level(dev_priv,
-						       sanitized_state.cdclk);
+	if (IS_ELKHARTLAKE(dev_priv))
+		sanitized_state.voltage_level =
+			ehl_calc_voltage_level(sanitized_state.cdclk);
+	else
+		sanitized_state.voltage_level =
+			icl_calc_voltage_level(sanitized_state.cdclk);
 
 	cnl_set_cdclk(dev_priv, &sanitized_state, INVALID_PIPE);
 }
@@ -1959,8 +1901,12 @@ static void icl_uninit_cdclk(struct drm_i915_private *dev_priv)
 
 	cdclk_state.cdclk = cdclk_state.bypass;
 	cdclk_state.vco = 0;
-	cdclk_state.voltage_level = icl_calc_voltage_level(dev_priv,
-							   cdclk_state.cdclk);
+	if (IS_ELKHARTLAKE(dev_priv))
+		cdclk_state.voltage_level =
+			ehl_calc_voltage_level(cdclk_state.cdclk);
+	else
+		cdclk_state.voltage_level =
+			icl_calc_voltage_level(cdclk_state.cdclk);
 
 	cnl_set_cdclk(dev_priv, &cdclk_state, INVALID_PIPE);
 }
@@ -2561,9 +2507,14 @@ static int icl_modeset_calc_cdclk(struct intel_atomic_state *state)
 
 	state->cdclk.logical.vco = vco;
 	state->cdclk.logical.cdclk = cdclk;
-	state->cdclk.logical.voltage_level =
-		max(icl_calc_voltage_level(dev_priv, cdclk),
-		    cnl_compute_min_voltage_level(state));
+	if (IS_ELKHARTLAKE(dev_priv))
+		state->cdclk.logical.voltage_level =
+			max(ehl_calc_voltage_level(cdclk),
+			    cnl_compute_min_voltage_level(state));
+	else
+		state->cdclk.logical.voltage_level =
+			max(icl_calc_voltage_level(cdclk),
+			    cnl_compute_min_voltage_level(state));
 
 	if (!state->active_pipes) {
 		cdclk = icl_calc_cdclk(state->cdclk.force_min_cdclk, ref);
@@ -2571,8 +2522,12 @@ static int icl_modeset_calc_cdclk(struct intel_atomic_state *state)
 
 		state->cdclk.actual.vco = vco;
 		state->cdclk.actual.cdclk = cdclk;
-		state->cdclk.actual.voltage_level =
-			icl_calc_voltage_level(dev_priv, cdclk);
+		if (IS_ELKHARTLAKE(dev_priv))
+			state->cdclk.actual.voltage_level =
+				ehl_calc_voltage_level(cdclk);
+		else
+			state->cdclk.actual.voltage_level =
+				icl_calc_voltage_level(cdclk);
 	} else {
 		state->cdclk.actual = state->cdclk.logical;
 	}
@@ -2819,11 +2774,7 @@ void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv)
 		dev_priv->display.modeset_calc_cdclk = vlv_modeset_calc_cdclk;
 	}
 
-	if (INTEL_GEN(dev_priv) >= 11)
-		dev_priv->display.get_cdclk = icl_get_cdclk;
-	else if (IS_CANNONLAKE(dev_priv))
-		dev_priv->display.get_cdclk = cnl_get_cdclk;
-	else if (IS_GEN9_LP(dev_priv))
+	if (INTEL_GEN(dev_priv) >= 10 || IS_GEN9_LP(dev_priv))
 		dev_priv->display.get_cdclk = bxt_get_cdclk;
 	else if (IS_GEN9_BC(dev_priv))
 		dev_priv->display.get_cdclk = skl_get_cdclk;