drm/i915: add basic Haswell DP link train bits

Previously, the DP register was used for everything. On Haswell, it
was split into DDI_BUF_CTL (which is the new intel_dp->DP register)
and DP_TP_CTL.

The logic behind this patch is based on a patch written by Shobhit
Kumar, but the way the code was written is very different.

Credits-to: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
[danvet: Fixup the logic error spotted by Jani Nikula.]
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_reg.h

@@ -4435,12 +4435,16 @@
 #define  DP_TP_CTL_LINK_TRAIN_MASK		(7<<8)
 #define  DP_TP_CTL_LINK_TRAIN_PAT1		(0<<8)
 #define  DP_TP_CTL_LINK_TRAIN_PAT2		(1<<8)
+#define  DP_TP_CTL_LINK_TRAIN_PAT3		(4<<8)
+#define  DP_TP_CTL_LINK_TRAIN_IDLE		(2<<8)
 #define  DP_TP_CTL_LINK_TRAIN_NORMAL		(3<<8)
+#define  DP_TP_CTL_SCRAMBLE_DISABLE		(1<<7)
 
 /* DisplayPort Transport Status */
 #define DP_TP_STATUS_A			0x64044
 #define DP_TP_STATUS_B			0x64144
 #define DP_TP_STATUS(port) _PORT(port, DP_TP_STATUS_A, DP_TP_STATUS_B)
+#define  DP_TP_STATUS_IDLE_DONE		(1<<25)
 #define  DP_TP_STATUS_AUTOTRAIN_DONE	(1<<12)
 
 /* DDI Buffer Control */

drivers/gpu/drm/i915/intel_dp.c

@@ -1470,7 +1470,19 @@ intel_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing)
 {
 	struct drm_device *dev = intel_dp->base.base.dev;
 
-	if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
+	if (IS_HASWELL(dev)) {
+		switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
+		case DP_TRAIN_VOLTAGE_SWING_400:
+			return DP_TRAIN_PRE_EMPHASIS_9_5;
+		case DP_TRAIN_VOLTAGE_SWING_600:
+			return DP_TRAIN_PRE_EMPHASIS_6;
+		case DP_TRAIN_VOLTAGE_SWING_800:
+			return DP_TRAIN_PRE_EMPHASIS_3_5;
+		case DP_TRAIN_VOLTAGE_SWING_1200:
+		default:
+			return DP_TRAIN_PRE_EMPHASIS_0;
+		}
+	} else if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
 		switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
 		case DP_TRAIN_VOLTAGE_SWING_400:
 			return DP_TRAIN_PRE_EMPHASIS_6;
@@ -1624,6 +1636,40 @@ intel_gen7_edp_signal_levels(uint8_t train_set)
 	}
 }
 
+/* Gen7.5's (HSW) DP voltage swing and pre-emphasis control */
+static uint32_t
+intel_dp_signal_levels_hsw(uint8_t train_set)
+{
+	int signal_levels = train_set & (DP_TRAIN_VOLTAGE_SWING_MASK |
+					 DP_TRAIN_PRE_EMPHASIS_MASK);
+	switch (signal_levels) {
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_0:
+		return DDI_BUF_EMP_400MV_0DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return DDI_BUF_EMP_400MV_3_5DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_6:
+		return DDI_BUF_EMP_400MV_6DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_9_5:
+		return DDI_BUF_EMP_400MV_9_5DB_HSW;
+
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_0:
+		return DDI_BUF_EMP_600MV_0DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return DDI_BUF_EMP_600MV_3_5DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_6:
+		return DDI_BUF_EMP_600MV_6DB_HSW;
+
+	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_0:
+		return DDI_BUF_EMP_800MV_0DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return DDI_BUF_EMP_800MV_3_5DB_HSW;
+	default:
+		DRM_DEBUG_KMS("Unsupported voltage swing/pre-emphasis level:"
+			      "0x%x\n", signal_levels);
+		return DDI_BUF_EMP_400MV_0DB_HSW;
+	}
+}
+
 static uint8_t
 intel_get_lane_status(uint8_t link_status[DP_LINK_STATUS_SIZE],
 		      int lane)
@@ -1680,8 +1726,44 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
 	struct drm_device *dev = intel_dp->base.base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret;
+	uint32_t temp;
 
-	if (HAS_PCH_CPT(dev) && (IS_GEN7(dev) || !is_cpu_edp(intel_dp))) {
+	if (IS_HASWELL(dev)) {
+		temp = I915_READ(DP_TP_CTL(intel_dp->port));
+
+		if (dp_train_pat & DP_LINK_SCRAMBLING_DISABLE)
+			temp |= DP_TP_CTL_SCRAMBLE_DISABLE;
+		else
+			temp &= ~DP_TP_CTL_SCRAMBLE_DISABLE;
+
+		temp &= ~DP_TP_CTL_LINK_TRAIN_MASK;
+		switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
+		case DP_TRAINING_PATTERN_DISABLE:
+			temp |= DP_TP_CTL_LINK_TRAIN_IDLE;
+			I915_WRITE(DP_TP_CTL(intel_dp->port), temp);
+
+			if (wait_for((I915_READ(DP_TP_STATUS(intel_dp->port)) &
+				      DP_TP_STATUS_IDLE_DONE), 1))
+				DRM_ERROR("Timed out waiting for DP idle patterns\n");
+
+			temp &= ~DP_TP_CTL_LINK_TRAIN_MASK;
+			temp |= DP_TP_CTL_LINK_TRAIN_NORMAL;
+
+			break;
+		case DP_TRAINING_PATTERN_1:
+			temp |= DP_TP_CTL_LINK_TRAIN_PAT1;
+			break;
+		case DP_TRAINING_PATTERN_2:
+			temp |= DP_TP_CTL_LINK_TRAIN_PAT2;
+			break;
+		case DP_TRAINING_PATTERN_3:
+			temp |= DP_TP_CTL_LINK_TRAIN_PAT3;
+			break;
+		}
+		I915_WRITE(DP_TP_CTL(intel_dp->port), temp);
+
+	} else if (HAS_PCH_CPT(dev) &&
+		   (IS_GEN7(dev) || !is_cpu_edp(intel_dp))) {
 		dp_reg_value &= ~DP_LINK_TRAIN_MASK_CPT;
 
 		switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
@@ -1768,8 +1850,11 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
 		uint8_t	    link_status[DP_LINK_STATUS_SIZE];
 		uint32_t    signal_levels;
 
-
-		if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
+		if (IS_HASWELL(dev)) {
+			signal_levels = intel_dp_signal_levels_hsw(
+							intel_dp->train_set[0]);
+			DP = (DP & ~DDI_BUF_EMP_MASK) | signal_levels;
+		} else if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
 			signal_levels = intel_gen7_edp_signal_levels(intel_dp->train_set[0]);
 			DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_IVB) | signal_levels;
 		} else if (IS_GEN6(dev) && is_cpu_edp(intel_dp)) {
@@ -1777,9 +1862,10 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
 			DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_SNB) | signal_levels;
 		} else {
 			signal_levels = intel_dp_signal_levels(intel_dp->train_set[0]);
-			DRM_DEBUG_KMS("training pattern 1 signal levels %08x\n", signal_levels);
 			DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
 		}
+		DRM_DEBUG_KMS("training pattern 1 signal levels %08x\n",
+			      signal_levels);
 
 		if (!intel_dp_set_link_train(intel_dp, DP,
 					     DP_TRAINING_PATTERN_1 |
@@ -1855,7 +1941,10 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
 			break;
 		}
 
-		if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
+		if (IS_HASWELL(dev)) {
+			signal_levels = intel_dp_signal_levels_hsw(intel_dp->train_set[0]);
+			DP = (DP & ~DDI_BUF_EMP_MASK) | signal_levels;
+		} else if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
 			signal_levels = intel_gen7_edp_signal_levels(intel_dp->train_set[0]);
 			DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_IVB) | signal_levels;
 		} else if (IS_GEN6(dev) && is_cpu_edp(intel_dp)) {
@@ -1902,6 +1991,9 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
 		++tries;
 	}
 
+	if (channel_eq)
+		DRM_DEBUG_KMS("Channel EQ done. DP Training successfull\n");
+
 	intel_dp_set_link_train(intel_dp, DP, DP_TRAINING_PATTERN_DISABLE);
 }