drm/i915: Program DPLL P1 dividers consistently

On g4x and pch the DPLL has two P1 dividers (for refresh rate
switching). Program the FPx1 P1 divider consistently to the reduced
clock P1 divider if available, otherwise just program it to the
same value as the FPx0 P1 divider.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210715093530.31711-9-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -779,42 +779,34 @@ static u32 pnv_dpll_compute_fp(const struct dpll *dpll)
 }
 
 static void i9xx_update_pll_dividers(struct intel_crtc_state *crtc_state,
+				     const struct dpll *clock,
 				     const struct dpll *reduced_clock)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	const struct dpll *clock = &crtc_state->dpll;
-	u32 fp, fp2 = 0;
+	u32 fp, fp2;
 
 	if (IS_PINEVIEW(dev_priv)) {
 		fp = pnv_dpll_compute_fp(clock);
-		if (reduced_clock)
 		fp2 = pnv_dpll_compute_fp(reduced_clock);
 	} else {
 		fp = i9xx_dpll_compute_fp(clock);
-		if (reduced_clock)
 		fp2 = i9xx_dpll_compute_fp(reduced_clock);
 	}
 
 	crtc_state->dpll_hw_state.fp0 = fp;
-
-	if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_LVDS) &&
-	    reduced_clock) {
 	crtc_state->dpll_hw_state.fp1 = fp2;
-	} else {
-		crtc_state->dpll_hw_state.fp1 = fp;
-	}
 }
 
 static void i9xx_compute_dpll(struct intel_crtc_state *crtc_state,
+			      const struct dpll *clock,
 			      const struct dpll *reduced_clock)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	const struct dpll *clock = &crtc_state->dpll;
 	u32 dpll;
 
-	i9xx_update_pll_dividers(crtc_state, reduced_clock);
+	i9xx_update_pll_dividers(crtc_state, clock, reduced_clock);
 
 	dpll = DPLL_VGA_MODE_DIS;
 
@@ -837,13 +829,17 @@ static void i9xx_compute_dpll(struct intel_crtc_state *crtc_state,
 		dpll |= DPLL_SDVO_HIGH_SPEED;
 
 	/* compute bitmask from p1 value */
-	if (IS_PINEVIEW(dev_priv))
-		dpll |= (1 << (clock->p1 - 1)) << DPLL_FPA01_P1_POST_DIV_SHIFT_PINEVIEW;
-	else {
+	if (IS_G4X(dev_priv)) {
 		dpll |= (1 << (clock->p1 - 1)) << DPLL_FPA01_P1_POST_DIV_SHIFT;
-		if (IS_G4X(dev_priv) && reduced_clock)
 		dpll |= (1 << (reduced_clock->p1 - 1)) << DPLL_FPA1_P1_POST_DIV_SHIFT;
+	} else if (IS_PINEVIEW(dev_priv)) {
+		dpll |= (1 << (clock->p1 - 1)) << DPLL_FPA01_P1_POST_DIV_SHIFT_PINEVIEW;
+		WARN_ON(reduced_clock->p1 != clock->p1);
+	} else {
+		dpll |= (1 << (clock->p1 - 1)) << DPLL_FPA01_P1_POST_DIV_SHIFT;
+		WARN_ON(reduced_clock->p1 != clock->p1);
 	}
+
 	switch (clock->p2) {
 	case 5:
 		dpll |= DPLL_DAC_SERIAL_P2_CLOCK_DIV_5;
@@ -858,6 +854,8 @@ static void i9xx_compute_dpll(struct intel_crtc_state *crtc_state,
 		dpll |= DPLLB_LVDS_P2_CLOCK_DIV_14;
 		break;
 	}
+	WARN_ON(reduced_clock->p2 != clock->p2);
+
 	if (DISPLAY_VER(dev_priv) >= 4)
 		dpll |= (6 << PLL_LOAD_PULSE_PHASE_SHIFT);
 
@@ -880,14 +878,14 @@ static void i9xx_compute_dpll(struct intel_crtc_state *crtc_state,
 }
 
 static void i8xx_compute_dpll(struct intel_crtc_state *crtc_state,
+			      const struct dpll *clock,
 			      const struct dpll *reduced_clock)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	const struct dpll *clock = &crtc_state->dpll;
 	u32 dpll;
 
-	i9xx_update_pll_dividers(crtc_state, reduced_clock);
+	i9xx_update_pll_dividers(crtc_state, clock, reduced_clock);
 
 	dpll = DPLL_VGA_MODE_DIS;
 
@@ -901,6 +899,8 @@ static void i8xx_compute_dpll(struct intel_crtc_state *crtc_state,
 		if (clock->p2 == 4)
 			dpll |= PLL_P2_DIVIDE_BY_4;
 	}
+	WARN_ON(reduced_clock->p1 != clock->p1);
+	WARN_ON(reduced_clock->p2 != clock->p2);
 
 	/*
 	 * Bspec:
@@ -958,12 +958,12 @@ static bool ilk_needs_fb_cb_tune(const struct dpll *dpll, int factor)
 }
 
 static void ilk_update_pll_dividers(struct intel_crtc_state *crtc_state,
+				    const struct dpll *clock,
 				    const struct dpll *reduced_clock)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	const struct dpll *clock = &crtc_state->dpll;
-	u32 fp, fp2 = 0;
+	u32 fp, fp2;
 	int factor;
 
 	/* Enable autotuning of the PLL clock (if permissible) */
@@ -979,30 +979,26 @@ static void ilk_update_pll_dividers(struct intel_crtc_state *crtc_state,
 	}
 
 	fp = i9xx_dpll_compute_fp(clock);
-
 	if (ilk_needs_fb_cb_tune(clock, factor))
 		fp |= FP_CB_TUNE;
 
-	if (reduced_clock) {
 	fp2 = i9xx_dpll_compute_fp(reduced_clock);
-
 	if (reduced_clock->m < factor * reduced_clock->n)
 		fp2 |= FP_CB_TUNE;
-	}
 
 	crtc_state->dpll_hw_state.fp0 = fp;
-	crtc_state->dpll_hw_state.fp1 = reduced_clock ? fp2 : fp;
+	crtc_state->dpll_hw_state.fp1 = fp2;
 }
 
 static void ilk_compute_dpll(struct intel_crtc_state *crtc_state,
+			     const struct dpll *clock,
 			     const struct dpll *reduced_clock)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	const struct dpll *clock = &crtc_state->dpll;
 	u32 dpll;
 
-	ilk_update_pll_dividers(crtc_state, reduced_clock);
+	ilk_update_pll_dividers(crtc_state, clock, reduced_clock);
 
 	dpll = 0;
 
@@ -1042,7 +1038,7 @@ static void ilk_compute_dpll(struct intel_crtc_state *crtc_state,
 	/* compute bitmask from p1 value */
 	dpll |= (1 << (clock->p1 - 1)) << DPLL_FPA01_P1_POST_DIV_SHIFT;
 	/* also FPA1 */
-	dpll |= (1 << (clock->p1 - 1)) << DPLL_FPA1_P1_POST_DIV_SHIFT;
+	dpll |= (1 << (reduced_clock->p1 - 1)) << DPLL_FPA1_P1_POST_DIV_SHIFT;
 
 	switch (clock->p2) {
 	case 5:
@@ -1058,6 +1054,7 @@ static void ilk_compute_dpll(struct intel_crtc_state *crtc_state,
 		dpll |= DPLLB_LVDS_P2_CLOCK_DIV_14;
 		break;
 	}
+	WARN_ON(reduced_clock->p2 != clock->p2);
 
 	if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_LVDS) &&
 	    intel_panel_use_ssc(dev_priv))
@@ -1117,7 +1114,8 @@ static int ilk_crtc_compute_clock(struct intel_crtc_state *crtc_state)
 		return -EINVAL;
 	}
 
-	ilk_compute_dpll(crtc_state, NULL);
+	ilk_compute_dpll(crtc_state, &crtc_state->dpll,
+			 &crtc_state->dpll);
 
 	if (!intel_reserve_shared_dplls(state, crtc, NULL)) {
 		drm_dbg_kms(&dev_priv->drm,
@@ -1246,7 +1244,8 @@ static int g4x_crtc_compute_clock(struct intel_crtc_state *crtc_state)
 		return -EINVAL;
 	}
 
-	i9xx_compute_dpll(crtc_state, NULL);
+	i9xx_compute_dpll(crtc_state, &crtc_state->dpll,
+			  &crtc_state->dpll);
 
 	return 0;
 }
@@ -1282,7 +1281,8 @@ static int pnv_crtc_compute_clock(struct intel_crtc_state *crtc_state)
 		return -EINVAL;
 	}
 
-	i9xx_compute_dpll(crtc_state, NULL);
+	i9xx_compute_dpll(crtc_state, &crtc_state->dpll,
+			  &crtc_state->dpll);
 
 	return 0;
 }
@@ -1318,7 +1318,8 @@ static int i9xx_crtc_compute_clock(struct intel_crtc_state *crtc_state)
 		return -EINVAL;
 	}
 
-	i9xx_compute_dpll(crtc_state, NULL);
+	i9xx_compute_dpll(crtc_state, &crtc_state->dpll,
+			  &crtc_state->dpll);
 
 	return 0;
 }
@@ -1356,7 +1357,8 @@ static int i8xx_crtc_compute_clock(struct intel_crtc_state *crtc_state)
 		return -EINVAL;
 	}
 
-	i8xx_compute_dpll(crtc_state, NULL);
+	i8xx_compute_dpll(crtc_state, &crtc_state->dpll,
+			  &crtc_state->dpll);
 
 	return 0;
 }