drm/i915/dg2: Add MPLLB programming for HDMI

At the moment we don't have a proper algorithm that can be used to
calculate PHY settings for arbitrary HDMI link rates.  The PHY tables
here should support the regular modes of real-world HDMI monitors.

Bspec: 54032
Cc: Matt Atwood <matthew.s.atwood@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
Reviewed-by: Matt Atwood <matthew.s.atwood@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210723174239.1551352-25-matthew.d.roper@intel.com

6 files changed, 355 insertions, 13 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 061a663f43b8..f48bc9786329 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -51,6 +51,7 @@
 #include "intel_panel.h"
 #include "intel_pps.h"
 #include "intel_psr.h"
+#include "intel_snps_phy.h"
 #include "intel_sprite.h"
 #include "intel_tc.h"
 #include "intel_vdsc.h"
@@ -3754,6 +3755,15 @@ void intel_ddi_get_clock(struct intel_encoder *encoder,
 						     &crtc_state->dpll_hw_state);
 }
 
+static void dg2_ddi_get_config(struct intel_encoder *encoder,
+				struct intel_crtc_state *crtc_state)
+{
+	intel_mpllb_readout_hw_state(encoder, &crtc_state->mpllb_state);
+	crtc_state->port_clock = intel_mpllb_calc_port_clock(encoder, &crtc_state->mpllb_state);
+
+	intel_ddi_get_config(encoder, crtc_state);
+}
+
 static void adls_ddi_get_config(struct intel_encoder *encoder,
 				struct intel_crtc_state *crtc_state)
 {
@@ -4616,7 +4626,9 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 	encoder->cloneable = 0;
 	encoder->pipe_mask = ~0;
 
-	if (IS_ALDERLAKE_S(dev_priv)) {
+	if (IS_DG2(dev_priv)) {
+		encoder->get_config = dg2_ddi_get_config;
+	} else if (IS_ALDERLAKE_S(dev_priv)) {
 		encoder->enable_clock = adls_ddi_enable_clock;
 		encoder->disable_clock = adls_ddi_disable_clock;
 		encoder->is_clock_enabled = adls_ddi_is_clock_enabled;
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 82298b073b36..378c05b52e37 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -9183,6 +9183,52 @@ verify_shared_dpll_state(struct intel_crtc *crtc,
 }
 
 static void
+verify_mpllb_state(struct intel_atomic_state *state,
+		   struct intel_crtc_state *new_crtc_state)
+{
+	struct drm_i915_private *i915 = to_i915(state->base.dev);
+	struct intel_mpllb_state mpllb_hw_state = { 0 };
+	struct intel_mpllb_state *mpllb_sw_state = &new_crtc_state->mpllb_state;
+	struct intel_crtc *crtc = to_intel_crtc(new_crtc_state->uapi.crtc);
+	struct intel_encoder *encoder;
+
+	if (!IS_DG2(i915))
+		return;
+
+	if (!new_crtc_state->hw.active)
+		return;
+
+	encoder = intel_get_crtc_new_encoder(state, new_crtc_state);
+	intel_mpllb_readout_hw_state(encoder, &mpllb_hw_state);
+
+#define MPLLB_CHECK(name) do { \
+	if (mpllb_sw_state->name != mpllb_hw_state.name) { \
+		pipe_config_mismatch(false, crtc, "MPLLB:" __stringify(name), \
+				     "(expected 0x%08x, found 0x%08x)", \
+				     mpllb_sw_state->name, \
+				     mpllb_hw_state.name); \
+	} \
+} while (0)
+
+	MPLLB_CHECK(mpllb_cp);
+	MPLLB_CHECK(mpllb_div);
+	MPLLB_CHECK(mpllb_div2);
+	MPLLB_CHECK(mpllb_fracn1);
+	MPLLB_CHECK(mpllb_fracn2);
+	MPLLB_CHECK(mpllb_sscen);
+	MPLLB_CHECK(mpllb_sscstep);
+
+	/*
+	 * ref_control is handled by the hardware/firemware and never
+	 * programmed by the software, but the proper values are supplied
+	 * in the bspec for verification purposes.
+	 */
+	MPLLB_CHECK(ref_control);
+
+#undef MPLLB_CHECK
+}
+
+static void
 intel_modeset_verify_crtc(struct intel_crtc *crtc,
 			  struct intel_atomic_state *state,
 			  struct intel_crtc_state *old_crtc_state,
@@ -9195,6 +9241,7 @@ intel_modeset_verify_crtc(struct intel_crtc *crtc,
 	verify_connector_state(state, crtc);
 	verify_crtc_state(crtc, old_crtc_state, new_crtc_state);
 	verify_shared_dpll_state(crtc, old_crtc_state, new_crtc_state);
+	verify_mpllb_state(state, new_crtc_state);
 }
 
 static void
diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 852af2b23540..b04685bb6439 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -51,6 +51,7 @@
 #include "intel_hdmi.h"
 #include "intel_lspcon.h"
 #include "intel_panel.h"
+#include "intel_snps_phy.h"
 
 static struct drm_device *intel_hdmi_to_dev(struct intel_hdmi *intel_hdmi)
 {
@@ -1850,6 +1851,16 @@ hdmi_port_clock_valid(struct intel_hdmi *hdmi,
 	if (IS_CHERRYVIEW(dev_priv) && clock > 216000 && clock < 240000)
 		return MODE_CLOCK_RANGE;
 
+	/*
+	 * SNPS PHYs' MPLLB table-based programming can only handle a fixed
+	 * set of link rates.
+	 *
+	 * FIXME: We will hopefully get an algorithmic way of programming
+	 * the MPLLB for HDMI in the future.
+	 */
+	if (IS_DG2(dev_priv))
+		return intel_snps_phy_check_hdmi_link_rate(clock);
+
 	return MODE_OK;
 }
 
diff --git a/drivers/gpu/drm/i915/display/intel_snps_phy.c b/drivers/gpu/drm/i915/display/intel_snps_phy.c
index 6d9205906595..1317b4e94b50 100644
--- a/drivers/gpu/drm/i915/display/intel_snps_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_snps_phy.c
@@ -3,6 +3,8 @@
  * Copyright © 2019 Intel Corporation
  */
 
+#include <linux/util_macros.h>
+
 #include "intel_de.h"
 #include "intel_display_types.h"
 #include "intel_snps_phy.h"
@@ -375,14 +377,172 @@ static const struct intel_mpllb_state *dg2_edp_tables[] = {
 	NULL,
 };
 
-int intel_mpllb_calc_state(struct intel_crtc_state *crtc_state,
-			   struct intel_encoder *encoder)
-{
-	const struct intel_mpllb_state **tables;
-	int i;
+/*
+ * HDMI link rates with 100 MHz reference clock.
+ */
+
+static const struct intel_mpllb_state dg2_hdmi_25_175 = {
+	.clock = 25175,
+	.ref_control =
+		REG_FIELD_PREP(SNPS_PHY_REF_CONTROL_REF_RANGE, 3),
+	.mpllb_cp =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT, 5) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP, 15) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT_GS, 64) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP_GS, 124),
+	.mpllb_div =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_DIV5_CLK_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_TX_CLK_DIV, 5) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_PMIX_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_V2I, 2),
+	.mpllb_div2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_REF_CLK_DIV, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_MULTIPLIER, 128) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_HDMI_DIV, 1),
+	.mpllb_fracn1 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_CGG_UPDATE_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_DEN, 143),
+	.mpllb_fracn2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_QUOT, 36663) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_REM, 71),
+	.mpllb_sscen =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_SSC_UP_SPREAD, 1),
+};
+
+static const struct intel_mpllb_state dg2_hdmi_27_0 = {
+	.clock = 27000,
+	.ref_control =
+		REG_FIELD_PREP(SNPS_PHY_REF_CONTROL_REF_RANGE, 3),
+	.mpllb_cp =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT, 5) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP, 15) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT_GS, 64) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP_GS, 124),
+	.mpllb_div =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_DIV5_CLK_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_TX_CLK_DIV, 5) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_PMIX_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_V2I, 2),
+	.mpllb_div2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_REF_CLK_DIV, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_MULTIPLIER, 140) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_HDMI_DIV, 1),
+	.mpllb_fracn1 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_CGG_UPDATE_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_DEN, 5),
+	.mpllb_fracn2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_QUOT, 26214) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_REM, 2),
+	.mpllb_sscen =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_SSC_UP_SPREAD, 1),
+};
+
+static const struct intel_mpllb_state dg2_hdmi_74_25 = {
+	.clock = 74250,
+	.ref_control =
+		REG_FIELD_PREP(SNPS_PHY_REF_CONTROL_REF_RANGE, 3),
+	.mpllb_cp =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT, 4) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP, 15) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT_GS, 64) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP_GS, 124),
+	.mpllb_div =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_DIV5_CLK_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_TX_CLK_DIV, 3) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_PMIX_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_V2I, 2) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FREQ_VCO, 3),
+	.mpllb_div2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_REF_CLK_DIV, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_MULTIPLIER, 86) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_HDMI_DIV, 1),
+	.mpllb_fracn1 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_CGG_UPDATE_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_DEN, 5),
+	.mpllb_fracn2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_QUOT, 26214) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_REM, 2),
+	.mpllb_sscen =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_SSC_UP_SPREAD, 1),
+};
+
+static const struct intel_mpllb_state dg2_hdmi_148_5 = {
+	.clock = 148500,
+	.ref_control =
+		REG_FIELD_PREP(SNPS_PHY_REF_CONTROL_REF_RANGE, 3),
+	.mpllb_cp =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT, 4) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP, 15) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT_GS, 64) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP_GS, 124),
+	.mpllb_div =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_DIV5_CLK_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_TX_CLK_DIV, 2) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_PMIX_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_V2I, 2) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FREQ_VCO, 3),
+	.mpllb_div2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_REF_CLK_DIV, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_MULTIPLIER, 86) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_HDMI_DIV, 1),
+	.mpllb_fracn1 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_CGG_UPDATE_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_DEN, 5),
+	.mpllb_fracn2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_QUOT, 26214) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_REM, 2),
+	.mpllb_sscen =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_SSC_UP_SPREAD, 1),
+};
+
+static const struct intel_mpllb_state dg2_hdmi_594 = {
+	.clock = 594000,
+	.ref_control =
+		REG_FIELD_PREP(SNPS_PHY_REF_CONTROL_REF_RANGE, 3),
+	.mpllb_cp =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT, 4) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP, 15) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_INT_GS, 64) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_CP_PROP_GS, 124),
+	.mpllb_div =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_DIV5_CLK_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_PMIX_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_V2I, 2) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FREQ_VCO, 3),
+	.mpllb_div2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_REF_CLK_DIV, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_MULTIPLIER, 86) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_HDMI_DIV, 1),
+	.mpllb_fracn1 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_CGG_UPDATE_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_EN, 1) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_DEN, 5),
+	.mpllb_fracn2 =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_QUOT, 26214) |
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_FRACN_REM, 2),
+	.mpllb_sscen =
+		REG_FIELD_PREP(SNPS_PHY_MPLLB_SSC_UP_SPREAD, 1),
+};
 
+static const struct intel_mpllb_state *dg2_hdmi_tables[] = {
+	&dg2_hdmi_25_175,
+	&dg2_hdmi_27_0,
+	&dg2_hdmi_74_25,
+	&dg2_hdmi_148_5,
+	&dg2_hdmi_594,
+	NULL,
+};
+
+static const struct intel_mpllb_state **
+intel_mpllb_tables_get(struct intel_crtc_state *crtc_state,
+		       struct intel_encoder *encoder)
+{
 	if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_EDP)) {
-		tables = dg2_edp_tables;
+		return dg2_edp_tables;
 	} else if (intel_crtc_has_dp_encoder(crtc_state)) {
 		/*
 		 * FIXME: Initially we're just enabling the "combo" outputs on
@@ -397,15 +557,41 @@ int intel_mpllb_calc_state(struct intel_crtc_state *crtc_state,
 		 * that to determine which table to use.
 		 */
 		if (0)
-			tables = dg2_dp_38_4_tables;
+			return dg2_dp_38_4_tables;
 		else
-			tables = dg2_dp_100_tables;
-	} else {
-		/* TODO: Add HDMI support */
-		MISSING_CASE(encoder->type);
-		return -EINVAL;
+			return dg2_dp_100_tables;
+	} else if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI)) {
+		return dg2_hdmi_tables;
 	}
 
+	MISSING_CASE(encoder->type);
+	return NULL;
+}
+
+int intel_mpllb_calc_state(struct intel_crtc_state *crtc_state,
+			   struct intel_encoder *encoder)
+{
+	const struct intel_mpllb_state **tables;
+	int i;
+
+	if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI)) {
+		if (intel_snps_phy_check_hdmi_link_rate(crtc_state->port_clock)
+		    != MODE_OK) {
+			/*
+			 * FIXME: Can only support fixed HDMI frequencies
+			 * until we have a proper algorithm under a valid
+			 * license.
+			 */
+			DRM_DEBUG_KMS("Can't support HDMI link rate %d\n",
+				      crtc_state->port_clock);
+			return -EINVAL;
+		}
+	}
+
+	tables = intel_mpllb_tables_get(crtc_state, encoder);
+	if (!tables)
+		return -EINVAL;
+
 	for (i = 0; tables[i]; i++) {
 		if (crtc_state->port_clock <= tables[i]->clock) {
 			crtc_state->mpllb_state = *tables[i];
@@ -515,3 +701,79 @@ void intel_mpllb_disable(struct intel_encoder *encoder)
 	 * We handle this step in bxt_set_cdclk().
 	 */
 }
+
+int intel_mpllb_calc_port_clock(struct intel_encoder *encoder,
+				const struct intel_mpllb_state *pll_state)
+{
+	unsigned int frac_quot = 0, frac_rem = 0, frac_den = 1;
+	unsigned int multiplier, tx_clk_div, refclk;
+	bool frac_en;
+
+	if (0)
+		refclk = 38400;
+	else
+		refclk = 100000;
+
+	refclk >>= REG_FIELD_GET(SNPS_PHY_MPLLB_REF_CLK_DIV, pll_state->mpllb_div2) - 1;
+
+	frac_en = REG_FIELD_GET(SNPS_PHY_MPLLB_FRACN_EN, pll_state->mpllb_fracn1);
+
+	if (frac_en) {
+		frac_quot = REG_FIELD_GET(SNPS_PHY_MPLLB_FRACN_QUOT, pll_state->mpllb_fracn2);
+		frac_rem = REG_FIELD_GET(SNPS_PHY_MPLLB_FRACN_REM, pll_state->mpllb_fracn2);
+		frac_den = REG_FIELD_GET(SNPS_PHY_MPLLB_FRACN_DEN, pll_state->mpllb_fracn1);
+	}
+
+	multiplier = REG_FIELD_GET(SNPS_PHY_MPLLB_MULTIPLIER, pll_state->mpllb_div2) / 2 + 16;
+
+	tx_clk_div = REG_FIELD_GET(SNPS_PHY_MPLLB_TX_CLK_DIV, pll_state->mpllb_div);
+
+	return DIV_ROUND_CLOSEST_ULL(mul_u32_u32(refclk, (multiplier << 16) + frac_quot) +
+				     DIV_ROUND_CLOSEST(refclk * frac_rem, frac_den),
+				     10 << (tx_clk_div + 16));
+}
+
+void intel_mpllb_readout_hw_state(struct intel_encoder *encoder,
+				  struct intel_mpllb_state *pll_state)
+{
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	enum phy phy = intel_port_to_phy(dev_priv, encoder->port);
+
+	pll_state->mpllb_cp = intel_de_read(dev_priv, SNPS_PHY_MPLLB_CP(phy));
+	pll_state->mpllb_div = intel_de_read(dev_priv, SNPS_PHY_MPLLB_DIV(phy));
+	pll_state->mpllb_div2 = intel_de_read(dev_priv, SNPS_PHY_MPLLB_DIV2(phy));
+	pll_state->mpllb_sscen = intel_de_read(dev_priv, SNPS_PHY_MPLLB_SSCEN(phy));
+	pll_state->mpllb_sscstep = intel_de_read(dev_priv, SNPS_PHY_MPLLB_SSCSTEP(phy));
+	pll_state->mpllb_fracn1 = intel_de_read(dev_priv, SNPS_PHY_MPLLB_FRACN1(phy));
+	pll_state->mpllb_fracn2 = intel_de_read(dev_priv, SNPS_PHY_MPLLB_FRACN2(phy));
+
+	/*
+	 * REF_CONTROL is under firmware control and never programmed by the
+	 * driver; we read it only for sanity checking purposes.  The bspec
+	 * only tells us the expected value for one field in this register,
+	 * so we'll only read out those specific bits here.
+	 */
+	pll_state->ref_control = intel_de_read(dev_priv, SNPS_PHY_REF_CONTROL(phy)) &
+		SNPS_PHY_REF_CONTROL_REF_RANGE;
+
+	/*
+	 * MPLLB_DIV is programmed twice, once with the software-computed
+	 * state, then again with the MPLLB_FORCE_EN bit added.  Drop that
+	 * extra bit during readout so that we return the actual expected
+	 * software state.
+	 */
+	pll_state->mpllb_div &= ~SNPS_PHY_MPLLB_FORCE_EN;
+}
+
+int intel_snps_phy_check_hdmi_link_rate(int clock)
+{
+	const struct intel_mpllb_state **tables = dg2_hdmi_tables;
+	int i;
+
+	for (i = 0; tables[i]; i++) {
+		if (clock == tables[i]->clock)
+			return MODE_OK;
+	}
+
+	return MODE_CLOCK_RANGE;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_snps_phy.h b/drivers/gpu/drm/i915/display/intel_snps_phy.h
index 205ab46f0b67..ca4c2a25182b 100644
--- a/drivers/gpu/drm/i915/display/intel_snps_phy.h
+++ b/drivers/gpu/drm/i915/display/intel_snps_phy.h
@@ -8,11 +8,18 @@
 
 struct intel_encoder;
 struct intel_crtc_state;
+struct intel_mpllb_state;
 
 int intel_mpllb_calc_state(struct intel_crtc_state *crtc_state,
 			   struct intel_encoder *encoder);
 void intel_mpllb_enable(struct intel_encoder *encoder,
 			const struct intel_crtc_state *crtc_state);
 void intel_mpllb_disable(struct intel_encoder *encoder);
+void intel_mpllb_readout_hw_state(struct intel_encoder *encoder,
+				  struct intel_mpllb_state *pll_state);
+int intel_mpllb_calc_port_clock(struct intel_encoder *encoder,
+				const struct intel_mpllb_state *pll_state);
+
+int intel_snps_phy_check_hdmi_link_rate(int clock);
 
 #endif /* __INTEL_SNPS_PHY_H__ */
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index bf4a816995dc..f82a7e24b5cc 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2317,12 +2317,15 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 
 #define SNPS_PHY_MPLLB_SSCEN(phy)		_MMIO_SNPS(phy, 0x168014)
 #define   SNPS_PHY_MPLLB_SSC_EN			REG_BIT(31)
+#define   SNPS_PHY_MPLLB_SSC_UP_SPREAD		REG_BIT(30)
 #define   SNPS_PHY_MPLLB_SSC_PEAK		REG_GENMASK(29, 10)
 
 #define SNPS_PHY_MPLLB_SSCSTEP(phy)		_MMIO_SNPS(phy, 0x168018)
 #define   SNPS_PHY_MPLLB_SSC_STEPSIZE		REG_GENMASK(31, 11)
 
 #define SNPS_PHY_MPLLB_DIV2(phy)		_MMIO_SNPS(phy, 0x16801C)
+#define   SNPS_PHY_MPLLB_HDMI_PIXEL_CLK_DIV	REG_GENMASK(19, 18)
+#define   SNPS_PHY_MPLLB_HDMI_DIV		REG_GENMASK(17, 15)
 #define   SNPS_PHY_MPLLB_REF_CLK_DIV		REG_GENMASK(14, 12)
 #define   SNPS_PHY_MPLLB_MULTIPLIER		REG_GENMASK(11, 0)