[Intel-gfx] [PATCH 3/4] drm/i915/display: Implement HOBL

["José Roberto de Souza" <jose.souza@intel.com>]

Hours Of Battery Life is a new GEN12+ power-saving feature that allows
supported motherboards to use a special voltage swing table for eDP
panels that uses less power.

So here if supported by HW, OEM will set it in VBT and i915 will try
to train link with HOBL vswing table if link training fails it fall
back to the original table.

Just not sure if DP compliance should also use this new voltage swing
table too, cced some folks that worked in DP compliance.

BSpec: 49291
BSpec: 49399
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
---
 drivers/gpu/drm/i915/display/intel_ddi.c      | 48 +++++++++++++++++--
 .../drm/i915/display/intel_display_types.h    |  2 +
 .../drm/i915/display/intel_dp_link_training.c | 20 +++++++-
 drivers/gpu/drm/i915/i915_drv.h               |  2 +
 drivers/gpu/drm/i915/i915_reg.h               |  2 +
 5 files changed, 69 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index c100efc6a2c4..a44e190de79f 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -692,6 +692,10 @@ static const struct cnl_ddi_buf_trans tgl_combo_phy_ddi_translations_dp_hbr2[] =
 	{ 0x6, 0x7F, 0x3F, 0x00, 0x00 },	/* 900   900      0.0   */
 };
 
+static const struct cnl_ddi_buf_trans tgl_combo_phy_ddi_translations_edp_hbr2_hobl[] = {
+	{ 0x6, 0x7F, 0x3F, 0x00, 0x00 }
+};
+
 static const struct ddi_buf_trans *
 bdw_get_buf_trans_edp(struct drm_i915_private *dev_priv, int *n_entries)
 {
@@ -2297,14 +2301,51 @@ static void cnl_ddi_vswing_sequence(struct intel_encoder *encoder,
 	intel_de_write(dev_priv, CNL_PORT_TX_DW5_GRP(port), val);
 }
 
+/*
+ * If supported return HOBL vswing table and set registers to enable HOBL
+ * otherwise returns NULL and unset registers to enable HOBL.
+ */
+static const struct cnl_ddi_buf_trans *
+hobl_get_combo_buf_trans(struct drm_i915_private *dev_priv,
+			 struct intel_encoder *encoder, int type, int rate,
+			 u32 level, int *n_entries)
+{
+	const u32 hobl_en = EDP4K2K_MODE_OVRD_EN | EDP4K2K_MODE_OVRD_OPTIMIZED;
+	enum phy phy = intel_port_to_phy(dev_priv, encoder->port);
+	struct intel_dp *intel_dp;
+
+	if (!HAS_HOBL(dev_priv) || type != INTEL_OUTPUT_EDP)
+		return NULL;
+
+	intel_dp = enc_to_intel_dp(encoder);
+	if (!intel_dp->try_hobl || rate > 540000) {
+		intel_de_rmw(dev_priv, ICL_PORT_CL_DW10(phy), hobl_en, 0);
+		return NULL;
+	}
+
+	drm_dbg_kms(&dev_priv->drm, "Enabling HOBL in PHY %c\n", phy_name(phy));
+	drm_WARN_ON_ONCE(&dev_priv->drm, level > 0);
+
+	intel_de_rmw(dev_priv, ICL_PORT_CL_DW10(phy), hobl_en, hobl_en);
+	/* Same table applies to TGL, RKL and DG1 */
+	*n_entries = ARRAY_SIZE(tgl_combo_phy_ddi_translations_edp_hbr2_hobl);
+	return tgl_combo_phy_ddi_translations_edp_hbr2_hobl;
+}
+
 static void icl_ddi_combo_vswing_program(struct drm_i915_private *dev_priv,
-					u32 level, enum phy phy, int type,
-					int rate)
+					 struct intel_encoder *encoder,
+					 u32 level, enum phy phy, int type,
+					 int rate)
 {
 	const struct cnl_ddi_buf_trans *ddi_translations = NULL;
 	u32 n_entries, val;
 	int ln;
 
+	ddi_translations = hobl_get_combo_buf_trans(dev_priv, encoder, type,
+						    rate, level, &n_entries);
+	if (ddi_translations)
+		goto hobl_found;
+
 	if (INTEL_GEN(dev_priv) >= 12)
 		ddi_translations = tgl_get_combo_buf_trans(dev_priv, type, rate,
 							   &n_entries);
@@ -2317,6 +2358,7 @@ static void icl_ddi_combo_vswing_program(struct drm_i915_private *dev_priv,
 	if (!ddi_translations)
 		return;
 
+hobl_found:
 	if (level >= n_entries) {
 		drm_dbg_kms(&dev_priv->drm,
 			    "DDI translation not found for level %d. Using %d instead.",
@@ -2424,7 +2466,7 @@ static void icl_combo_phy_ddi_vswing_sequence(struct intel_encoder *encoder,
 	intel_de_write(dev_priv, ICL_PORT_TX_DW5_GRP(phy), val);
 
 	/* 5. Program swing and de-emphasis */
-	icl_ddi_combo_vswing_program(dev_priv, level, phy, type, rate);
+	icl_ddi_combo_vswing_program(dev_priv, encoder, level, phy, type, rate);
 
 	/* 6. Set training enable to trigger update */
 	val = intel_de_read(dev_priv, ICL_PORT_TX_DW5_LN0(phy));
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 30b2767578dc..9e7dbff7dd43 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1365,6 +1365,8 @@ struct intel_dp {
 
 	/* Display stream compression testing */
 	bool force_dsc_en;
+
+	bool try_hobl;
 };
 
 enum lspcon_vendor {
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index e4f1843170b7..db078780542f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -37,12 +37,24 @@ intel_dp_dump_link_status(const u8 link_status[DP_LINK_STATUS_SIZE])
 void intel_dp_get_adjust_train(struct intel_dp *intel_dp,
 			       const u8 link_status[DP_LINK_STATUS_SIZE])
 {
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
 	u8 v = 0;
 	u8 p = 0;
 	int lane;
 	u8 voltage_max;
 	u8 preemph_max;
 
+	if (intel_dp->try_hobl) {
+		/*
+		 * Do not adjust, try now with the regular table using VSwing 0
+		 * and pre-emp 0
+		 */
+		intel_dp->try_hobl = false;
+		drm_dbg_kms(&dev_priv->drm, "HOBL vswing table failed link "
+			    "training, switching back to regular table\n");
+		return;
+	}
+
 	for (lane = 0; lane < intel_dp->lane_count; lane++) {
 		u8 this_v = drm_dp_get_adjust_request_voltage(link_status, lane);
 		u8 this_p = drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
@@ -92,9 +104,13 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
 }
 
 static bool
-intel_dp_reset_link_train(struct intel_dp *intel_dp,
-			u8 dp_train_pat)
+intel_dp_reset_link_train(struct intel_dp *intel_dp, u8 dp_train_pat)
 {
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+
+	if (intel_dp_is_edp(intel_dp) && dev_priv->vbt.edp.hobl)
+		intel_dp->try_hobl = true;
+
 	memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set));
 	intel_dp_set_signal_levels(intel_dp);
 	return intel_dp_set_link_train(intel_dp, dp_train_pat);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1e060de3edc4..8c2fb4da70fd 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1678,6 +1678,8 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
 #define INTEL_DISPLAY_ENABLED(dev_priv) \
 		(drm_WARN_ON(&(dev_priv)->drm, !HAS_DISPLAY(dev_priv)), !i915_modparams.disable_display)
 
+#define HAS_HOBL(dev_priv) (INTEL_GEN(dev_priv) >= 12)
+
 static inline bool intel_vtd_active(void)
 {
 #ifdef CONFIG_INTEL_IOMMU
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index e9d50fe0f375..a7a8d12fa49d 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1896,6 +1896,8 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define  PWR_DOWN_LN_3_1_0		(0xb << 4)
 #define  PWR_DOWN_LN_MASK		(0xf << 4)
 #define  PWR_DOWN_LN_SHIFT		4
+#define  EDP4K2K_MODE_OVRD_EN		(1 << 3)
+#define  EDP4K2K_MODE_OVRD_OPTIMIZED	(1 << 2)
 
 #define ICL_PORT_CL_DW12(phy)		_MMIO(_ICL_PORT_CL_DW(12, phy))
 #define   ICL_LANE_ENABLE_AUX		(1 << 0)
-- 
2.26.2

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx